Glossary of Terms for Thoracic Radiology: Recommendations of the Nomenclature Committee of the Fleischner Society1

509 .. , . . . . Glossary of Terms for Thoracic Radiology: Recommendations of the Nomenclature Committee Fleischner Society1 The Fleischner Soc...
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Glossary of Terms for Thoracic Radiology: Recommendations of the Nomenclature Committee Fleischner Society1 The Fleischner Society was founded in 1969 by a group of radiologists to honor the memory of Felix Fleischner and to promote the exchange of information between basic scientists and clinical investigators interested in chest disease. Today this multidisciplinary group is best known for the Symposia on Chest Disease that it conducts annually, but it has sought, in the words of its motto, “to advance knowledge of the normal and diseased chest” in various other ways. The Glossary presented here represents one such effort. The Glossary was originally proposed at the first general meeting of the Society of 1 971 in the belief that standardization

of terms

with

respect

to the

description

of radiographic

findings would facilitate the exchange of information. Various members of the Society have contributed to its development over the intervening years, and though such an undertaking is never truly completed, the Glossary is now judged to be sufficiently inclusive to be of general interest. The Society, therefore, authorized its publication as a report of the Nomenclature Committee in May 1983. The development of a glossary is a process that casts light on both the meaning of words and on the basics of human behavior. The use of words, it appears, is a highly personal attribute of the individual, and any disagreement with that usage is instinctively viewed as a personal assault: A nomenclature committee does not need a chairman; it needs a “peace-keeping force”! It is, therefore, a great tribute to those who participated that they were ultimately able to put personal bias and national linguistic differences aside and to agree on the definitions presented here. The Committee, comprising more “splitters” than “lumpers,” has sought to identify nuances of meaning that distinguish words of similar connotation and has systematically rejected the argument that “everyone says it that way” as a justification for the misuse of a word. It has also attempted to indicate whether specific terms are truly descriptors or are, in fact, diagnostic conclusions; and if the latter, whether or not they can appropriately be based solely on radiographic evidence. It is hoped that publication of this Glossary will stimulate interest in the standardization of descriptive terminology in chest radiology, that some will adhere to the definitions pre-

1

Address reprint requests to W. J. Tuddenham,

AJR

143:509-517,

September

Department

1984 0361-803X/84/1433-0509

of Radiology. 0 American

of the

sented here, and that those who do not will, at least, become more thoughtful in their choice of words. Thanks are due to those members of the Society who launched this effort: Gordon Cumming (Midhurst, England) and E. Robert Heitzman (Syracuse, NY); to those who sustamed it: John J. Fennessy (Chicago, IL), Paul J. Friedman (San Diego, CA), Ronald Grainger(Sheffield, England), William H. Northway, Jr. (Palo Alto, CA), and the late George Jacobson (Los Angeles, CA); and most particularly to those on whom fell the burden of bringing it to fruition: John H. M. Austin (New York, NY), Robert G. Fraser (Birmingham, AL), David H. Trapnell (London, England) and Morris Simon (Boston, MA). William J. Tuddenham Chairman,

Editor’s

Nomenclature Committee The Fleischner Society

Note

At its recent meeting in Santa Fe, the Fleischner Society reaffirmed its hope this Glossary will prove helpful in refining the radiographic vocabulary for describing and thinking about thoracic disease. The Society also realizes these definitions and comments on their usage (evaluations) may not satisfy all readers. A certain dogmatism has been required to reach final statements about terms that may be used differently by others. To achieve a wider consensus on the acceptance of controversial terms, the Society invites comments, criticisms, and suggested additions. These may be directed to the AJR Editorial Office or to Dr. Robert Fraser (Department of Radiology, University of Alabama Medical Center, 619 5. 19th St., Birmingham, AL 35233). Dr. Fraser is the new chairman of the Nomenclature Committee; the committee will synthesize constructive suggestions into revisions in the Glossary. Readers are urged to respond to this invitation and to help the Society reduce imprecision in our vocabulary so the complexities of thoracic disease may be better understood and communicated. MMF

Pennsylvania Roentgen

Hospital, 8th and Spruce Sts., Philadelphia, Ray Society

PA 19107.

510

FLEISCHNER

A abscess,

but including

n, -es. 1. Pathol. An inflammatory mass lung parenchyma, the central part of which

within

has undergone purulent liquefaction necrosis. It may communicate with the bronchial tree. 2. Radio!. A mass within lung parenchyma which, if it communicates with the bronchial tree, contains a cavity. Otherwise, a pulmonary mass can be considered to represent an abscess in the morphologic sense only by inference. -Qualifiers: Expressing clinical course: acute, chronic. Expressing etiology: bacterial, fungal, etc. Expressing site of involvement: lung, mediastinal, etc. Evaluation: An inferred conclusion, the use of which as a radiobogic diagnosis is appropriate only with reference

to masses

of presumed

infec-

tious origin; cf. cavity. absorber,

n, -s. Radio!phys.

Any object that atten-

uates an x-ray beam. pattern, n, -a. Radio!. A collection of round, poorly defined, discrete or partly confluent opacities in the lung, each 4-8 mm in diameter and together producing an extended, inhomogeneous shadow. -Synonyms: rosette pattem, acinonodose pattem (used specifically with reference to

acinar

endobronchial spread of tuberculosis), alveolar pattem (inaccurate descriptor; not recommended). -Evaluation: An inferred conclusion usually used as a descriptor. An acceptable term. acinar shadow, n, -a. Radio!. A round or ovoid, poorly defined pulmonary opacity 4-8 mm in

diameter,

presumed

to represent

an anatomic

acinus renderedopaque by consolidation. Usually used only in the presence ofmany such opacities; cf. acinar pattern. -Evaluation: An inferred conclusion

applicable as a radiobogic de-

sometimes

scriptor. acinus,

n, -I. Anat. The part of the lung distal to a

terminal

bronchiole.

It consists

of respiratory

bronchioles, alveolar ducts, alveolar sacs, alveoli, and their blood vessels, lymphatics, and supporting tissues. aerate, v. 1. To fill with air. 2. To expose to air. 3. To oxygenate. aerated, adj. 1. Inflated, filled wtih air (lungs). 2. Air-containing (paranasal sinuses). 3. Exposed to air (blood). aeration, n. Physiol/radiol. 1. The state of containing air. 2. The state or process of admitting or of being filled or inflated with air. 3. The state or process of being exposed to air. -Qualifiers:

over- (preferred) or hyper- ; under- (preferred) or hypo-. -Synonyms: inflation. See also vanillaoxygenation. -Evaluation: Acceptable term with reference to inspiratory phase of respiration. Inflation is preferred in sense 2. air, n. Radio!. Gas within the body, regardless of its composition or site. -Synonym: gas. -Evaluation: The word air should be used to refer only to inspired atmospheric gas. With reference to hen,

pneumothoraces,

subcutaneous

emphysema

or etc., gas is

the content of the stomach, colon, the preferred term. air bronchogram, n, -a. Radio!. The radiographic shadow of an air-filled bronchus peripheral to the hilum and surrounded by airless lung (whether by virtue of absorption of air, replacement of air or both);

a finding

generally

regarded

as evidence

of the patency

of the more proximal airway; hence, any bandlike tapering and/or branching lucency within opacafled lung corresponding in size and distribution to a bronchus or bronchi and presumed to represent an air-filled segment of the bronchial tree. -Evaluation: A specific feature of radiobogic anatomy whose identity is often

inferred. A useful and recommended term. level, n, -s. Radio!. See fluid level. airspace, n. Anat. The gas-containing part of the

air-fluid

lung exclusive of the

purely

conducting

airways,

SOCIETY

the respiratory

GLOSSARY

bronchioles.

monic window.

-adj. Pathol/Physiol/Radiol. Of or pertaining to any process believed to be confined to the anatomic airspace or to a part thereof(e.g., airspace consolidation). -Synonyms: acinar, alveolar. Evaluation: Inferred conclusion appropriately based

on radiologic

evidence

and an acceptable

descriptor.

air trapping, n. 1. Pathophysiol. The retention of excess air in all or part of the lung as a result of airway closure during the expiratory maneuver; classically implies an increasing amount of retamed air at equivalent expiratory positions in successive expiratory maneuvers. 2. Radio!. The retention of excess air in all or in some part of the lung at any stage of expiration. -Evaluation: 2. A specific radiologic statement to be used only if excess air retention is demonstrated by a dynamic study (e.g. , inspiration-expiration radiography or fluoroscopy). Not to be used with reference to ovennflation

of the lung at full inspiration

(total lung capacity). airway, n. Anat. 1. A collective term for the airconducting passages from the larynx to and induding the terminal bronchioles. 2. Any air-conducting tube or passage. -adj. Pathol/Physiol/Radiol. Of or pertaining to the anatomic airway or a part thereof (e.g.. dostructive airway disease). -Evaluation: Inferred conclusion appropriately based on radiobogic cvidance. An acceptable descriptor. alveolarizatlon, n. Radio!. The opacification of clusters of minute airways (presumed to be alveoli) by a contrast agent. -Evaluation: Excessive fill-

ing of peripheral airways by a contrast agent usually used for bronchography may opacity respiratory bronchioles, but seldom alveoli. Thus, the correct term is bronchiolar filling orbronchiolar opacification. alveolar pore, n, -s. Anat/Physiol. A microscopic communication between alveoli. Together with the canals of Lambert and direct airway anastomoses, the alveolar pores provide for the collateral passage of gas or liquid from one pulmonary unit to another; of. collateral ventilation. -Synonym: pore of Kohn. anterior junction line, n. Radio!. A vertically oriented linear or curvilinear opacity about 1 mm wide and commonly projected on the tracheal air shadow. It is produced by the shadows of the

right and left pleurae in intimate contact between the aerated lungs anterior to the great vessels and sometimes the heart; hence, it never extends above the suprastemal notch. -Synonyms: anterior mediastinal septum, anterior mediastinal line. -Evaluation: A specific feature of radiologic anatomy; preferred to cited synonyms. sortie knob, n. RadiO!. That part of the aortic arch that is seen end-on in a frontal radiograph. In the normal, it is characterized by a sharply defined, arcuate superolateral border and lies to the left of the trachea above the main pulmonary artery. -Synonyms: aortic knuckle. -Evaluation: A specific feature of radiobogic anatomy. An ac-

ceptable term. window, n. 1. Anat. A mediastirtal space bounded anteriorly by the ascending aorta; posteriorly by the descending aorta; superiorly by the aortic arch; inferiorly by the left pulmonary artery; medially by the left side of the trachea, left main bronchus, and esophagus; and laterally by the left lung. Within it are situated the ductus ligament. the left recurrent laryngeal nerve, lymph nodes, and fat. 2. Radio!. A zone of relative lucency in the mediastinal shadow, which is best seen in the left anterior oblique projection and which correspondstothe anatomic space defined above. On a frontal chest radiograph, the lateral

aortopulmonary

margin

of this

monary window

space constitutes the interface. -Synonym:

AJR:143,

aortopulaortopul-

of radiologic arterlovenous

September

1984

-Evaluation: 2. A specific feature anatomy. An acceptable term. flstUla, n, -ae. 1. Pathol anat. A

direct communication between an artery and a vein that bypasses the capillary bed. 2. Radio!. A shadow complex, comprising a nodular pulmonary opacity associated with dilated vascular shadows, that is presumed to represent an arteriovenous fistula in the anatomic sense. (Such lesions are often multiple.) -Synonyms: arteriovenous aneurysm, arteriovenous malformation. Arteriovenous fistula or aneurysm refers to a lesion of congenital or traumatic origin; arteriovenous

malformation

should be reserved for le-

sions ofcongenital origin. -Qualifiers: traumatic, congenital. -Evaluation: In conventional radiographs, an inferred conclusion sometimes justifled by the radiographic evidence alone. In pubmonary arteriography, an explicit radiographic diagnosis. atelectasis, n. 1. Pathol phys. Less than normal kiflation ofall or part ofthe lung with corresponding diminution in lung volume. 2. Radio!. Radiologic evidence of diminished volume affecting all or part of a lung, which may or may not include bss ofnormal lucency in the affected part of lung. (This finding is not to be confused with diminished volume produced by resection of pulmonary tissue.) -Qualifiers: Expressing mechanism: resorption (obstructive), secondary to airway obstruction; relaxation (passive, compression), secondary to the effect of an adjacent space-occupying process; surfactant deficit; cicatrization (scar), secondary to fibrotic contraction. Expressing distribution: total pulmonary, bobar, segmental, subsegmental, platelike, discoid, platter, bin-

ear. Expressing severity: minor (mild), moderate, marked (severe), total (complete). -Synonyms: anectasis, loss of volume, collapse. Anectasis is usually used in reference to failure of lung expan. sion ume and can

in the newborn;

atelectasis

and loss of vol-

refer to acquired diminution in lung volume do not connote severity. Collapse, in Ameri-

usage, refers to total atelectasis; in British collapse has the more general meaning of atelectasis (2, above). -Evaluation: A conclusion conceming pathophysiobogy that is appropriately based on radiographic evidence alone. attenuate, v. Radio!phys. To reduce the energy of an x-ray beam. attenuation, n. Radio! phys. A collective term for the processes (absorption and scattering) by which the energy of an x-ray beam is diminished In its passage through matter. azygoesophageal recess, n. 1. Anat. A space or recess in the right side of the mediastinum into which the medial edge of the right bower lobe (crista pulmonis) extends. It is limited superiorly by the arch of the azygos vein, posteriorly by the azygos vein in front of the vertebral column, and

usage,

medially by the esophagus and its adjacent structures. (The exact relation between the medial edge of the lung and the mediastinal structures varies.) 2. Radio!. In a frontal chest radiograph, a vertically oriented interface between air in the right lower lung and the adjacent mediastinum that represents the medial limit of the anatomic azygoesophageal recess. -Evaluation: 2. A spacific feature of radiologic anatomy. The use of the term recess to identify a linear shadow is mappropriate; medial boundary or limit or azygoesophageal recess is preferred. azygos vein, n. Radio!. A slight, ovoid prominence of the mediastinal shadow commonly seen in frontal chest radiographs in the angle formed by the right main bronchus and the trachea. The shadow is produced principally by the azygos veln projected end-on, but azygos lymph nodes may contribute to it. -Evaluation: A feature of

radiobogic anatomy of some descriptive value rel-

MR:143,

FLEISCHNER

September1984

ative to the status of the systemic venous volume and pressure and azygos vain flow volume; an term.

B

cated, thin-walled lucency contiguous with the pleura, usually at the lung apex. -Synonyms: type I bubla(Reid), bulla, air cyst. -Evaluation: 2. conclusion,

seldom

justified

by the

radiograph alone. Bulla or air cyst is preferred. belle, n, -as. 1. Patho! anat. a. A sharply demarcated region of emphysema 1 cm or more in diameter. b. An abnormal space within the lung 1 cm or more in diameter that may contain only gas (type II of Reid), or may contain, in addition, blood

vessels

and ruptured

alveolar

walls

(type

Ill of Reid). Aform ofpulmonary

aircyst. 2. Radio!. lucency 1 cm or more in

Any sharply demarcated diameter within the lung, the wall of which is less than 1 mm thick. -Qualifiers: small, medium, large. -Synonyms: blab, air cyst; pneumatocele is not a proper synonym. -Evaluation: 2. An inferred conclusion. usually justified by the radiographic findings. An acceptable term. butterfly distribution, n. Radio!. See batwing disthbutlon. (To be distinguished from the use of this term in general medicine to describe the distribution of certain cutaneous lesions.)

C calcific, adj. 1. Of or pertaining to deposits of insoluble calcium salts. 2. Radio! [said of a shadow). a. Significantly moreopaquethan shad-

ows of soft tissues of comparable therefore,

thickness and,

presumed to represent a calcified tissue. b. Similar in opacity to shadows of structures of comparable thickness that are known to be calcified. calcification, n, -S. 1. The state or process of being rendered calcareous by the deposition of calcium salts. 2. A calcified structure. Specifically: pulmonary calcification, n. 1. Pathophysiol. a. The process by which one or more deposits of calcsum salts are formed within lung tissue or within a pulmonary lesion. b. Such a deposit of calcium salts. 2. Radio!. A calcific opacity within the lung that may be organized in the sense of concentric lamination, for example, but which does not display the trabecular organization of true bone. Qualifiers: eggshell, popcorn, etc. (q.v.) -Evaluation: An explicit statement; may be used as a descriptor. A useful term. To be distinguished from pulmonary ossification (q.v.). calcified, adj. 1. Having undergone calcification; containing calcium safts. 2. Radio!. Containing calcific shadows. calcify, v. To make or to become stony or calcareous by the deposition or secretion of calcium salts. cardiac rncisura, n. Radio!. The concavity in the

511

GLOSSARY

left heart border seen in the frontal (or right anterior oblique) chest radiograph just below the

left hilum and representing the junction between the main pulmonary artery and the left ventricular myocardium. The tip of the left atilal appendage may underlie the rncisura. -Evaluation: A feature of radiobogic anatomy. An acceptable

band shadow, n, -s. Radio!. See linear opacity. batwlng distribution, n. RadiO!. A spatial arrangement of radiographic opacities in a frontal radiograph that bears a vague resemblance to the shape of a bat in flight; said of coalescent, poorly defined opacities that are nearly bilaterally symmetric and that are confined to the central oneto two-thirds of the lungs. (Lesions that produce such shadows are not necessarily peripheral or central in location.) -Synonym: butterfly distribution. -Evaluation: A radiologic descriptor of limited usefulness. blab, n, -a. 1. Patho! anat. A gas-containing space within the visceral pleura of the lung. A form of pulmonary air cyst. 2. RadiO!. A sharply demar-

An inferred

SOCIETY

term.

sa#{241}nslangle, n. Anal/Radio!. The angle formed between the right and left main bronchi in a frontal chest radiograph. -Synonyms: bifurcation angb, angle of tracheal bifurcation. -Evaluation: A definitive anatomic and radiologic measurement. cavIty, n, -lea. 1. PatPiol ens!. A gas-filled space within a zone ofpulmonary consolidation or within a mass or nodule, produced by the expulsion of a necrotic part of the lesion via the brOnchial tree. 2. RadiO!. A lucency within a zone of pulmonary consolidation, a mass. or a nodule; hence, a lucent area within the lung that may or may not contain a fluid level and that is surrounded by a wall, usually of varied thickness. -Evaluation: 2. An inferred conclusion often used as a descriptor. The term expresses pathologic anatomy without causative connotation. It is a useful radiobogic descriptor; it is not synonymous with abscess, which may exist without cavitation. circumscribed, adj. Radio!. Possessing a cornpletely or nearly completely visible border. Evaluation: An acceptable descriptor: cf. defined. coalescent, adj. Radio!. Joined together; said of multiple opacities joined to form a single opacity, but stlH individually identifiable; cf. confluent, composite. -Evaluation: An acceptable descrip-

with or without evidence of enlargeheart chambers occurring in association with evidence of chronic lung disease. -Qualifiers: acute, chronic. -Evaluation: 2. An inferred radiologic conclusion that depends on radiographic signs that are usually, but not invariably, reliable; an acceptable descriptor. Dcspite pathology def. 1, radiologic evidence of cardiornegaly need not be present. cyst, n, -S. 1. Patho! anat. A circumscribed space, 1 cm ormore in diameter, containing gas or liquid, whose wall is generally thin, weN defined. and composed of a variety of ceflular elements. 2. Radio!. A circumscribed lucency or opacity within the lung or mediastinurn, 1 cm or more in diameter, that is presumed to represent a cyst in the pathologic sense. -Qualifiers: 1. foregut (bronchogenic. esophageal duplication); postinfection. 2. air. -Evaluation: 2. This term is appropriate for the description of any thin-walled, gas-contaming pulmonary space of uncertain cause whose wall is more than 1 mm thick. The term is entirely nonspecific and, if possible, a more spacific term(bleb, bul!a,pneumatocele) is preferred. hypertension mont

of the right

D

condemned. The term coin may be descriptive of the shadow, but certainly not of the lesion producing it. composite, adj. Radio!. Comprising more than one element; said of a shadow complex made up of multiple contiguous or superimposed elements that may or may not be separately identifiable. consolidate, V. 1. To become firm or hard (as by solidifying). 2. To cause to become firm or hard. consolidated, adj. Having become firm or solid; having undergone consolidation. consolidation, n, -S. 1. Pathophysiol. a. The proness by which air in the lung is replaced by the products of disease rendering the lung solid (as in pneumonia). b. The state of pulmonary tissue so Solidified. 2. Radio!. An essentially homogefocus opacity in the lung characterized by little or no loss of volume, effacement of blood vessel shadows, and sometimes by the presence of an air bronchogram (q.v.). Applicable only in an appropriate clinical setting when the opacity can with reasonablecertainty beattributed to replacement of alveolar air by exudate, transudate, or tissue. -Evaluation: 2. An inferred conclusion. A useful term when used in strict accord with the definitiOn above. Not to be used with reference to any homogeneous opacity. contrast medium, n, -Ia. RadiO!. An agent administered to render the lumen of a hollow structure, vessel. or viscus more or less opaque than its surroundforthe purposeof radiographic imaging. -Synonyms: contrast agent, opaque medium, opaque. -Evaluation: The use of contrast or dye

adj. Radio!. Possessing density (q.v.). Usually used in describing or comparing radiographs or radiographic shadows with respect to their light transmission. -Synonyms: black, heavily exposed. -Evaluation: A recommended term ,ri the context defined. Should not be used in referring to the opacity of an absorber to x-radiation. See opaque, opacity. density, n, -Isa. 1. Photom/Radiol. a. The property of an exposedand processed photographic emulsion thatdetermines itslight absorptlon/transmissiori characteristics; hence: b. The opacity of a radiographic shadow to visible bight; film blackening. 2. RadiO!. A qualitative expression of the degree of film blackening usually expressed in terms of the blackening of one film or shadow relative to another. 3. Photom. A quantitative expression of the degree of film blackening defined as: density = bogio X intensity (incident light)[intensity (transmitted light); optical density. 4. RadiO!. The shadow of an absorber more opaque to x-rays than its surround; an opacity or radiopacity: 5. The degree of opacity of an absorber to x-rays, usually expressed in terms of the nature of the absorber (e.g., bone density). 6. Phys. The mass of a substance per unit volume. -Synonyms: 1. light absorption. film blackening. 4. opacity. radiopacity. -Qualifiers: 2. increased, decreased. 3. increased, decreased, maximum. 5. air, water, metal, soft tissue, bone, fat; increased, decreased, etc. -Evaluation: In dots. 1-3, the term refers to a fundamental characteristic of the radiograph. This use is recornmended. In dots. 4 and 5, the term refers to the character of an absorber and has an exactly opposite connotation with respect to film blackening. Because of this potential confusion, the term should never be used to mean an opacity (radiopacity). diffuse, adj. 1. Widespread. 2. Pathophysioi. Widely distributed through an organ or type of tissue. 3. Radio!. Widespread and continuous Lsaid of shadows and, by inference, of the states or processes producing them). -Synonyms: dis-

to refer to a contrast medium is to be condemned, as is the use of the plural form, contrast media, to refer to a single contrast agent. cor pulmonale, n. 1. Patho! anat/Clin. Right ventricular hypertrophy and/or dilatation occurring as a result of an abnormality of lung structure or function. 2. Radio!. Evidence of pulmonary arterial

the context of chest radiology, diffuse connotes widespread, anatomically continuous, but not necessarily complete involvement of the lung or other thoracic structure or tissue; disseminated connotes widespread but anatomically discontinuous involvement; generalized connotes corn-

tor. coin lesion, n. Radio!. A sharply defined, circular opacity within the lung. suggestive of the appearance of a coin and usually representing a spherical or nodular lesion. -Synonyms: pulmonary nodule, pulmonary mass. -Evaluation:

A radiologic descriptor,

the use of which is to be

dense,

seminated, generalized,

systemic, widespread.

In

FLEISCHNER

512

plete or nearly complete

involvement,

whereas

systemic connotes involvement of a thoracic structure or tissue as part of a process involving the entire body. -Evaluation: 3. A useful and acceptable term. -v. To spread, to extend in continuity in all

directions. dirty chest, n. Radio!. An appearance of the lungs characterized by acompbex ofabnormal shadows of wide distribution and varying form and character. -Synonym: dirty lung. -Evaluation: A colloquial

descriptor

so indefinite

as to defy

ac-

curate definition. To be rejected in favor of more precise descriptors. disseminate, v. To spread, as seed. dissemInated, adj. 1. Widespread; sown as seed. 2. Pathophysiol. Widely but discontinuously distributed through an organ or type of tissue. 3. Radio!. Widespread but anatomically discontinuous

[said of shadows

and, by inference,

of the

states or processes producing them]. -Eva!uation: 3. A useful and acceptable term. doubling time, n, -a. Radio!. The time in which a pulmonary nodule or mass doubles in volume (increases in diameter by a factor of 1 .25): a semiquantitative expression of the growth rate of a lesion. -Evaluation: An acceptable term. The concept of growth rate is of very limited value as a criterion for distinguishing benign from malignant nodules.

E eggshell calcification, n. Radio!. Thin, sharply dofined, curvilinear, calcific opacities occurring in the periphery of a lesion or anatomic structure such as a lymph node. -Synonym: curvilinear calcification. -Evaluation: An acceptable radiologic descriptor. embolism, n. 1. Pathol. The complete or partial destruction ofthe lumen ofa blood vessel, usually an artery, by the sudden impaction of foreign material carried in the blood stream; cf. infarclion. 2. Radio!. A complex of radiographic and/or scintigraphic abnormalities presumed to represent embolism in the pathologic sense. -Evaluation: An inferred conclusion that in some cases can be based on radiographic or scintigraphic evidence alone. embolizatlon, n. Pathol. The pathologic process by which the lumen of a blood vessel is suddenly obstructed by blood clot or foreign material carried out in the bloodstream. -Qualifiers: thera-

peutic, referring to the technique by which the lumen of a blood vessel is deliberately occluded by the introduction offoreign objects or materials. embolus, n. -i. 1. Patho!. A blood clot or mass of foreign material that has been carried in the bloodstream and that partly or completely ccciudes the lumen of a blood vessel; Cf. thrombus. 2. Radio!. A lucent defect or obstruction within an opacifled vessel presumed to represent an embolus

in the pathologic

Expressing

sense.

clinical course:

-Qualifiers:

acute, chronic.

Ex-

pressing nature of embolic material: air, fat, amniotic fluid, parasitic, neoplastic. tissue, foreign materials (e.g., iodized oil, mercury, talc). Miscellaneous: septic, therapeutic, paradoxic. -Eva!uation: 2. A radiologic conclusion that may appro-

priately

be based

on arteriographic

evidence

alone. emphysema, n. 1. Pathol anat. a. A morbid condition of the lung characterized by abnormally cxpanded air spaces distal to the terminal bronchicle with or without destruction of the air-space

walls (per Ciba Conference, 1959). b. As above, but “with destruction of the walls of involved air spaces specified tion, 1961 , and

(per World American

Health OrganizaThoracic Society

SOCIETY

GLOSSARY

[ATS], 1962). 2. Radio!. Hyperinflatlon (q.v.) of all or part of one or both lungs. with or without associated alteration in pulmonary vascular pattem, presumed to represent morphologic emphyserna; applicable only in an appropriate clinical

sethng

and,

in the sense

not applicable to spasmodic

of

the

ATS

definition,

asthma or cornpen-

satory hyperinflation. -Qualifiers: Morpho!. contribobular, panlobular, paraseptal, focal-dust, alveolar duct, paracicatricial, etc.; Clin. local, genoral, bobar, segmental, senile, compensatory, surgical; mild, moderate, severe, etc. -Synonyms: None; overinflation and hyperaeration are not strictly synonymous with emphysema; emphysematous lungs are invariably overinflated, but overmnflated lungs are not invariably emphysematous. -Evaluation: 2. An inferred conclusion acceptable only if used in strict accordance with the definition above. exudate, n, -S. 1. Pathophysiol. a. Highly protelna000us fluid that may or may not contain inflam-

matory cells, is derived from the blood, is elaborated as part of the inflammatory response of the lung. pleura, or other tissues, and is deposited in extravascular tissue spaces and on tissue surfaces. b. An accumulation ofsuch fluid. 2. Radio!. A poorly defined opacity in the lung that neither destroys nor displaces its gross architecture; applicable only to an opacity that, on the basis of clinical or other evidence, can be attributed with reasonable certainty to a pulmonary infection or other inflammatory process. -Evaluation: 2. An inferred conclusion usually used as a descriptor. A useful and acceptable term when used in accordance with the definition above. To be distinguished from transudate. exudation, n. The process by which exudate (vs.) is formed. exudative, adj. Of or pertaining

to an exudate.

F fibrocalcific, adj. Radio!. Of or pertaining to sharply defined, linear, and/or nodular opacities containing cabclficalion(s)(q.v.), usually occurring in the upper lobes and presumed to represent old granubornatous lesions-Evaluation: A widely used and acceptable radiobogic descriptor. flbronodular,adj. Radio!. Oforpertainingto sharply defined, approximately circular opacities, occurring singly or in dusters, usually in the upper lobes of the lungs and associated with linear opacities and distortion (retraction) of adjacent structures. A finding usually presumed to represent old granubomatous disease, but no inference concerning the activity of such a lesion is justified on the basis of a single radiograph-Evaluation: An inferred conclusion usually used as a radiologic descriptor. Its use is not recommended. fibrosis, n. 1. PotPie!. a. Cellular fibrous tissue or dense acellular collagenous tissue. b. The

process of proliferation

of fibroblasts

leading to

the formation of fibrous or collagenous tissue. 2. Radio!. Any opacity presumed to represent fibrous or collagenous tissue; applicable to linear, nodular, or stellate opacities that are sharply defined, that are associated with evidence of loss of volume in the affected part of the lung and/or with deformity of adjacent structures, and that show no change over a period of months or years. Also applicable with caution to a diffuse pattem of opacity if there is evidence of progressiveboss oflung volumeor ifthe pattern of opacity is unchanged over time, with or without compensatory overmnflation.-Evaluation: 2. An inferred conclusion often used as a radiobogic descriptor. An acceptable term if used in strict accordance with the criteria cited. fIbrotic, adj. 1. Pathol. Of or pertaining to fIbrosis

AJR:143,

September 1984

(vs.). 2. Radio!.

Of or pertaining to any opacity or pattern of opacities presumed to represent fibrous tissue-Evaluation: 2. An inferred conclusion usually used as a radiobogic descriptor. Acceptable if used in strict accordance with the criteria cited under fibrosis (vs.). fIlm, n, -a. RSdiOL 1. The generic term for a radiahon-recording medium consisting of a photonsensitive emulsion coated on a flexible cellulose acetate or Mylar support. 2. A specific radiationrecording medium coated with an identified emulsion and having particular, predictable imaging properties. (This film is more sensitive than that.”) 3. A unit or sheet of such a radiation recording medium. 4. A processed radiograph (col!oq).-Evaluation: Film properly refers to the

unexposed,

unprocessed

raw material

of radi-

ographic

recordings; radiograph properly refers to the exposed, processed product of radiographic recording. The use of film as a synonym for radiograph in referring to an exposed and processed diagnostic recording is not recoinmended. -v, -ad, -ing. Radio!. To record or examine radiographically; to expose a radlograph.-Syn-

onyms: to x-ray, to radiograph, to expose a radiograph, to record a radiograph-Evaluation: Film in this sense is usually used in contradistinction to screen, to distinguish a radiographic from a fluoroscopic procedure. Its use is acceptable (particularly in British usage), but to expose a radiograph is preferred. film contrast factor, n. Radio! phys. The slope of the film characteristic curve (a plot of density vs. bog relative exposure); hence, the rate of change of film blackening (optical density) as a function of exposure-Synonyms: film gamma, film gradent; these terms are not strictly synonymous with film contrast factor, but are closely related to it in meaning-Evaluation: A fundamental characteristic of a radiographic emulsion. filter, n, -s. 1. Radiolphys. A device (usually sheet aluminum or copper) placed in the primary x-ray beam for the purpose of preferentially absorbing low-energy photons that otherwise would be absorbed by the patient. 2. A shaped metallic absorber placed in the primary x-ray beam to attenuate certain areas of the beam preferentially. See trough filter-Qualifiers: 1. primary, secondary, mherent, added; 2. trough, wedge. filtration, n. RadiO! phys. The process of attenuatrng the x-ray beam preferentially with respect to photon energy and/or spatial distribution-Qua!ifiers: inherent, added, total-Evaluation: A fundamental concept of radiation physics of clinical iniportance in radiation protection. fissure, n, -S. 1. Mat. Any cleft or infolding of the surface of a structure; hence, in the lungs, the

mfolding of visceral pleura that separates

one

lobe or part of a lobe from another. a. Interlobar fissures are produced by two layers of visceral pleura. b. Anomalous fissures may be complete or incomplete, usually separate segments rather than lobes and, in the case of the azygos fissure, may be formed by two layers of visceral and parietal pleura. 2. Radio!. A linear opacity normally 1 mm or less in width that corresponds in position and extent to the anatomic separation of pulmonary lobes or segments-Qualifiers: minor, major, horizontal, oblique, accessory, anomalous, azygos, inferior accessory-Synonym: la. interlobar septa.-Eva!uation: 2. A specific feature of radiobogic anatomy; an appropriate and useful term. Flelschner line, n, -a. Radio!. A straight, curved, or rregular linear opacity that is Visible in multiple projections; is usually situated in the lower half of the lung; is usually approximately horizontal, but may be oriented in any direction; and may or may not appear to extend to the pleural surface.

AJR:143,

FLEISCHNER

September1984

Such lines vary markedly in length and width; their exact pathologic significance is unknown.Qualifiers: In radiologic description, the location, length. width, and orientation of such a line should be specified-Synonyms: None; platelike, discoid, and platter atelectasis should not be used as synonyms. In the absence of clear histologic evidence of the significance of F. lines, this inferred identification of such lines with a

form of atelectasis is unwarranted-Evaluation: An acceptable term. The term linearopacity properlyqualified with respectto location, dimensions, and orientation is to be preferred, however. fluffy, adj. Radio![said of opacities]. Poorly defined, lacking clear-cut margins; resembling down or fluff. -Synonyms: shaggy, poorly defined. Evaluation: An imprecisedescriptoroflimited usefulness. fluid bevel, n. Radio!. The shadow complex produced by a horizontal x-ray beam traversing a space containing both gas and liquid or, less

often, two liquids of different

attenuation

char-

acteristics. Hence, a horizontal interface between zones of relative lucency above and opacity be-

low. -Synonyms: air-fluid level (fluid level is proferred), gas-fluid level, gas-liquid level. -Evaluation: A useful and acceptable descriptor.

G gas shadow, n. 1. Pathophysiol/Clin. A shadow of such exceptional lucency relative to adjacent anatomic shadows and to the inferred thickness of the absorber as to exclude the possibility of its representing a solid or liquid absorber. -Evaluation: An inferred conclusion appropriately based

on radiographic descriptor. ground-glass,

evidence alone and useful as a

adj.

Radio!

ance]. Any extended,

[usually

with

appear-

finely granular pattem

of

pulmonary opacity within which normal anatomic details are partly obscured; from a fancied resemblance to etched or abraded glass. -Evaluation: A nonspecific radiologic descriptor oflimited usefulness.

H heart failure, n. 1. Pathophysio!/Cin. Inability of the heart to satisfy the circulatory needs of the tissues of the body without raising ventricular enddiastolic pressure above 1 2 mm Hg, even though filling pressures may be adequate. 2. Radio!. The presence within the thorax of a complex of signs

of pulmonary

or systemic

venous hypertension pul-

including, but not limited to, cardiomegaly, monary bboodflow redistribution, interstitial

and/

or alveolar edema, generalized decrease in pubmonary volume, and, in the case of right ventricular failure only, generalized systemic venous distension. -Qualifiers: Expressing course of development: acute, chronic. Expressing nature of involvement: left, right, biventricular. -Synonyms: cardiac decompensation, cardiac failure, congestive heart failure. -Evaluation: 1. An acceptabbe term used in the clinical and pathophysiobogic sense. 2. An inferred conclusion justified by the presence of cited radiographic findings in an appropriate clinical setting. Cardiac decompensation or congestive heart failure are the proferred terms. hernia, herniation, n. Clin/Patho! anat/Radio!. The

protrusion

of all or part of an organ or tissue

through an abnormal opening. -Evaluation: An inferred conclusion to be used only within the precise terms of the definition. Thus, the word is appropriate in relation to a diaphragmatic hernia,

SOCIETY

513

GLOSSARY

but should not be used with reference to pulmonary overinflation with mediastinal displacement. hilum, n, -a. 1. Anat. A depression or pit in that part of an organ where the vessels and nerves enter. 2. Radio!. The composite shadow at the root of each lung produced by bronchi, arteries and

veins, lymph nodes, nerves, brOnChial vessels, and associated areolar tissue. -Synonyms: hilus, -I, lung root. -Evaluation: 2. A specific element ofradiologic anatomy. Hilum and hila are preferred to hilus and hili. -adj. hilar. homogeneous, adj. Radio!. Of uniform opacity and texture throughout. -Antonyms: inhornogeneous, nonhomogeneous, heterogeneous. Evaluation: An acceptable radiologic descriptor. lnhomogeneous is the preferred antonym as a descriptor of radiographic shadows. -n. homey. honeycomb pattern. n. 1. Patho!. A multitude of irregular cystic spaces in pulmonary tissue that are generally lined with bronchiolar epithelium and have thickened walls composed of dense fibrous tissue, with or without areas of chronic inflammation. 2. Radio!. A number of closely ap-

proximated ring shadows representing air spaces 5-10 mm in diameter with walls 2-3 mm thick that resemble a true honeycomb; a finding whose occurrence implies “end-stage lung. -Synonyms: None; coarse reticular pattern and coarse reticulonodular pattem are sometimes used as synonyms, but are inaccurate descriptors in this context and are not recommended. -Evaluation: A radiobogic desctiptorthat has been loosely used in the past and, therefore, with imprecise meaning. It is recommended that it be used strictly in accordance with the dimensional limits cited above, in which case it will have specific significanoe. Hounsfield unit, n, -a. Radio!phys. The unit (‘/ooo) of an arbitrary scale on which the x-ray attenuahon of air, water, and compact bone are defined to be -1000, 0, and +1000, respectively. Each such unit represents 0.1% difference in attenuation with respect to that of water. Abbr: H. hyperemia, n. 1. Patho!. An excess of blood in a part of the body; engorgement. 2. Physiol. Increased blood flow as part of the inflammatory response. 3. Radio!. Apparent increase in number or caliber of small vessels secondary to an inflammatory process. ynonym: pleonemia. -Eva!uation: An inferred conclusion appropriately used as a descriptor only in arteriography. adj. hyperemic. hypertension, n. Clin. Greater than normal systolic and/or diastolic pressure within the systemic or pulmonary vascular bed. Generally accepted empirical boundary levels are as follows: systemic arterial h., >1 40 mm Hg systolic, >90 mm Hg diastolic; systemic venous h., >12 mm Hg; pul-

monary arterial h., >30 mm Hg systolic, >15 mm Hg diastolic; pulmonary venous h., >1 2 mm Hg. -Evaluation: An inferred conclusion, but oxcept in the case of systemic arterial hypertension, it can be approximated the basis of radiologic

with

useful

accuracy

on

evidence.

infarct, n, -S. 1. Patholanat. a. A region of ischemic necrosis surrounded by hyperemic tissue resultmeg from occlusion of the region’s feeding vessel, usually by an embolus; a complete infarct. b. A region of tissue injury and hemorrhage resulting

from occlusion usually Radio!.

of the region’s

temporal development sidered

feeding vessel,

by an embolus; an incomplete infarct. 2. A pulmonary opacity that by virtue of its to result

and clinical setting is con-

from thromboembolic

occlusion

of a feeding vessel. Such an opacity is commonly, but not exclusively, hump-shaped and pleuralbased when seen in profile; poorly defined and round when viewed en face. (Subsequent events may establish that the opacity was the result of either hemorrhage or tissue necrosis.) -Synonym: infarction. -Evaluation: 1. Infarct is proferred to infarction in this sense. 2. An inferred conclusion, which, in the proper clinical sethng,

may be based

on the radiograph.

The word

should not be used in the absenceof a pulmonary opacity. -V. -ad. Pathol. To produce an infarct, def. 1 above. infarction, n, -a. 1. Pathol physiol. The process of infarct formation. 2. Patho! anat. An infarct. bnflhtrate, n, -a. 1. Pathophysiol. a. Any substance or type of cell that occurs within or spreads through the interstices (interstitium and/or alveoli)

of the lung, that is foreign to the lung, or that accumulates in greater than normal quantity within it. b. An accumulation of such a substance or type of cell. 2. Radio!. a. A poorly defined opacity in the lung that neither destroys nor displaces the gross morphology of the lung and is presumed to represent an infiltrate in the pathophysiologic sense. b. Any poorly defined opacity in the lung. -Evaluation: Majority: An inferred and often unwarranted conclusion used as a descriptor. The term is almost invariably used in sense 2b, in which it serves no useful purpose, and lacking a specific connotation is so variably used as to cause great confusion. Its use as a

descriptor

is to be condemned.

Minority:

Were

the term to be used in strict accordance with definition 2a, it would be a useful descriptor to distinguish processes that do not distort lung architecture from expanding processes that do. -v. 1. To penetrate the interstices of. 2. To

spread or cause to spread by infiltration. infiltrated, adj. 1. Having entered or spread by penetration of the interstices of a tissue. 2. Hayrng undergone infiltration. infiltration, n. 1. The process by which substances and/or cells spread through lung tissue via its mterstices without destroying or displacing its normal architecture. 2. See infiltrate. def. lb. inflate, v. To expand, to swell with gas. inflated, adj. Expanded or filled with gas. -Qualitiers: See below. inflation, n. Ptiysio!/Radio!. The state or process of being expanded or filled with gas; used specifically with reference to the expansion of the lungs with air. -Qualifiers: over- (preferred) or hyper-; under- (preferred) or hypo-. ynonyms: aeraton, inhalation, inspiration, ventilation. Inflation connotes expansion with gas or air. Aeration connotes the admission of air, exposure to air. Inhalation refers specifically to the act of drawing

air into the lungs in the process of breathing (as opposed to exhalation); and inspiration with reference to breathing, is similar in connotation. Ventilation connotes both the intake and expubsin of air from the lungs. -Evaluation: The word inflation avoids the confusion that surrounds the meanings of aeration and ventilation as a result of common misusage. It is the preferred term. interface, n. Radio!. The boundary between the shadows of two juxtaposed structures or tissues of different texture or opacity. -Synonyms: edge. border, silhouette, junction. -Evaluation: A useful radiologic descriptor. interstitlum, n. l.Anat/Radio!. Acontinuum of loose connective tissue throughout the lung comprising three subdivisions: (i) the bronchovascular (ax-

lab), surrounding

the bronchi, arteries, and veins

from the lung root to the level of the respiratory bronchiole; (2) the parenchymal (acinar). situated between alveolar and capillary basement mombranes; and (3) the subpleural, situated beneath

514

FLEISCHNER

the pleura as well as in the interlobar septa. Synonym: interstitial space. -Evaluation: A useful anatomic term. The interstitium of the lung is not normally visible radiographically; it becomes visible only when disease(e.g., edema) increases its volume and attenuation. -adj. Interstitial.

K Kerley

line,

A septal depending

n, -5 [usually in the plural]. Radio!. a. line (q.v.). b. A linear opacity, which, on its location,

extent,

and orientation,

may be further classified as follows: K. A line: An essentially straight linear opacity 2-6 cm long and 1 -3 mm wide, usually situated in an upper lung zone, that points toward the hilum centrally and is directed toward, but does not extend to, the pleural surface peripherally. K. B line: A straight linear opacity 1 .5-2 cm long and 1-2mm wide, usually situated at the lung base and orb-

ented at right angles to the pleural surface with which it is usually in contact peripherally. K. C lines [always in the plural]: linear opacities producing

A group

of branching,

the appearance of a fine net, situated at the lung base and representing K. B lines seen en face. -Synonyms: septal lines, lymphatic

lines.

Except

when

it is essential

to distinguish A, B, and C lines, the term seota! line is to be preferred. Lymphatic line is anatomically inaccurate and should never be used. Evaluation: A specific feature of pathologic/radiologic anatomy. An acceptable but not preferred term.

L line, n. Radio!. An extended longitudinal shadow (in the lung or mediastinum, an opacity) no greater than 2 mm in width; cf. stripe. -Evaluation: A useful term appropriately used in the description of radiographic shadows within the mediastinum (e.g., anteriorjunction line)orlung(e.g., interlobar fissures). linear opacIty, bling a line;

Radio!. A shadow resemany elongated opacity of approximately uniform width. -Qualifiers: The length, width, anatomic location, and orientation of such a shadow should be specified. -Synonyms: line, line shadow, linear shadow, band shadow. Band shadow and line shadow have been used by some to identity elongated shadows more than 5 mm wide and less than 5 mm wide, respectively. Linear opacity qualified by a statement of specific dimensions is to be proferred. -Evaluation: Ageneric radiologicdescnptor of great usefulness. The term includes a variety of linear shadows whose anatomic location, orientation, and dimensions imply their specific anatomic or pathologic significance (e.g., septal lines). Unear opacity is to be preferred to more specific anatomic or pathologic terms (e.g., discold atelectasis), unless the true nature of the

SOCIETY

GLOSSARY

The terminal unit of an acinus; the part of the lung distal to the terminal respiratory bronchiole. It comprises alveolar ducts, alveolar sacs, Primary:

alveoli, and their accompanying blood vessels, lymphatics, and supporting tissues. 2. Secondary: A variable number of acini (usually 3-5) bounded, in mostcases, bythin connective tissue septa. -Evaluation: 1. Acinus is the preferred anatomic/physiologic unit of lung structure. 2. The word lobule when unmodified refers to a secondary lobule. The concept of the primary lobule as defined has been largely abandoned. bocal, adj. Radio!. Occupying orconfined toa limited space within a defined structure; cf. circumscribed. -Synonyms: localized, focal. -Mtonyms: generalized, general, widespread. -Evaluation: An acceptable descriptor. lucency. n, -lee. Radio!. 1. The capacity to transmit light (translucency); hence, by extension, the capacity to transmit x-radiation. 2. The degree of x-

AJR:143,

discrete pulmonary opacities that are generally uniform in size and widespread in distribution and each of which is 2 mm or less in diameter. Synonym: micronodular pattern. -Evaluation: An acceptable descriptor without causative connotation. mucold impaction, n. Pathol/Radiol. A broad linear and/or branching opacity (I-, Y-, or V-shaped) caused by the presence of thick, tenacious mucus within a proximal airway (bobar, segmental, or subsegmental bronchus) and usually associated with airway dilatation. -Evaluation: An inferred conclusion without precise causative connotation. A useful descriptor. MiiIer maneuver, n. Physiol. Inspiration against a closed glottis, usually, but not necessarily, from

a position of residual volume, for the purpose of producing transient decrease in intrathoracic pressure.

ray transmission of an object, usually expressed in terms of transmission of one object relative to another. 3. The shadow of an absorber that attenuates the primary x-ray beam less effectively than do surrounding absorbers. Hence, in a radiograph, any circumscribed area that appears more nearly black (of greater photometric density) than its surround. Usually applied to the shadows of air or fat when surrounded by more effective absorbers such as muscle, exudate, etc. ynonyms: translucency, transradiancy. Evaluation: This term, used by analogywith opecity, is acceptable in American usage, although it is etymobogically indefensible. In British usage, transradiancy is preferred. lucent, adj. Radio!. Capable of transmitting radiant energy; specifically, x-radiation. lymphadenopathy, n. Clin/Patho! anat/Radiol. Any abnormality of lymph nodes; by common usage, usually restricted to enlargement oflymph nodes. -Synonyms: lymph node enlargement (proferred), adenopathy. -Evaluation: Lymph nodes are not glands. Lymphadenopathy and adonopathy are, therefore, inappropriate terms and any reference to lymph glands is to be condamned.

N nodular pattern, n. Radio!. A cOllection of innumerable, small, roughly circular, discrete pulmonary opacities ranging in diameter from 2 to 10 mm, generally uniform in size, widespread in distribution, and without marginal spiculation; cf. reticubonodular pattern. -Evaluation: An acceptable radiologic descriptor without specific pathologic or causative implications. The size of the nodules should be specified, either as a range or as an average. nodule, n, -s. 1. Morphol/Gen’l med. Any small, nearly spherical collections of differentiated tis-

sue. 2. Radio!. Any pulmonary

is incomplete. 2. Radio!. One of the principal divisions of the lungs (usually three on the right, two on the left) that are separated in whole or in part by pleural fissures. lobular, adj. Anat. Of or pertaining to a pulmonary lobule. lobule, n, -a. Mat. A unit of lung structure. 1.

or pleural lesion

represented in a radiograph by a sharply defined, discrete, nearly circular opacity 2-30 mm in diameter. - Qualifiers: Should always be qualified with respect to size, location, border characteristics, number, and opacity. -Synonym: coin lesion (q.v.); cf. mass. -Evaluation: A useful and recommended descriptor to be used in preference to coin lesion.

n, -*5. hence,

shadow is known or can be inferred with reasonable certainty. bobar, adj. Anat/Radiol. Of or pertaining to a lobe. lobe, n, -5. 1. Mat/Radio!. One of the principal divisions of the lungs (usually three on the right, two on the left) each of which is enveloped by visceral pleura except at the lung root and in any area of developmental deficiency where a fissure

September1984

0

M

n. 1. Physio!. Less than normal blood flow to the lungs or a part thereof. 2. Radio!. General or local decrease in the apparent width of visible pulmonary vessels, suggesting less than normal blood flow. -Qualifiers: acute, chronic, local, general. -Synonym: reduced blood flow. Evaluation: An inferred conclusion appropriately based on the radiographic appearance and usually used as a descriptor. An acceptable term. adj.OligemiC. opacIty. n. -bee. Radio!. 1. ImpervIousness to raoligemia,

n, -S [usually in the plural]. Radio!. A descriptor variously used with reference to: (1) the shadows produced by normal pulmonary blood vessels; (2) the shadows produced by a combination of normal pulmonary structures (blood vessels, bronchi, etc.), or (3) abnormal pulmonary shadows of no specific characteristics of significance. -Synonyms: opacity, [usually] linear opacity. Qualifiers: The type, dimensions, and anatomicdistribut,on of such shadows should be specified (e.g., bronchovascular, trabecular). The term should not be used without qualification. -Evaluation: When used alone, a vague descriptor of no value; not recommended. With proper qualifIcation, the term is acceptable, but opacity or shadow is usually to be preferred. mass, n, -es. 1. Morpho!/Gen’lmed. Any cOllection of tissue differentiated from surrounding tissues. 2. Radio!. Any pulmonary or pleural lesion reprosented in a radiograph by a discrete opacity greater than 30 mm in diameter (without regard marking, vague

to contour, border characteristics,

or homogeneity). but explicitly shown or presumed to be cxtended in all three dimensions. -Qualifiers: Should always be qualified with respect to size, location, contour, definition, homogeneity, opacity, and number. -Synonyms: None; of. nodule. -Evaluation: 2. A useful and recommended doscriptor. mlliary pattern, n, -a. Radio!. A collection of tiny

dent energy; specifically,

x-rays; the capacity to

attenuate

an x-ray beam. 2. The degree of x-ray attenuation produced by an absorber, usually expressed in terms of the attenuation of one absorber relative to another. 3. The shadow of an absorber that attenuates the x-ray beam more

effectively than do surrounding absorbers. Hence, in a radiograph, any circumscribed area that appears more nearly white (of lesser photometric density) than its surround. Usually applied to the shadows of nonspecific pulmonary colbections of fluid, tissue, etc., whose attenuation cxcoeds that of the surrounding aerated lung. Synonym: 3. radiopacity; cf. density. -Evaluation: 3. An essential and recommended radiobogic descriptor. In the context of radiologic reporting, radiopaque is acceptable but appears redundant, particularly since radio- does not serve to distinguish between the opacity of an absorber to xrays and opacity of a radiographic shadow to

AJR:143,

September

FLEISCHNER

1984

visible light rays. Radiopaque is preferred in Butish usage, nevertheless. Density (q.v.) should never be used in this context. opaque, n, -S. Radio!. That which is opaque (Webster). Specifically, a contrast medium that is opaque to x-rays. -Synonyms: contrast mediem, contrast agent, contrast material. -Evaluation: A concise and acceptable term. Contrast medium, agent, and material are preferred, however. NB.: The terms contrast and contrast media (when referring to a single agent) are colboquial, grammatically incorrect, and should not be used. -adj. Radio!. Impervious to x-rays. Synonym: radlopaque. -Evaluation: Opaque and radiopaque are both acceptable terms; opaque is preferred. See opacity. ossific, adj. Of or pertaining to bone. ossification, n, -5. The state or process of being ossified. Specifically: pulmonary ossification, n. 1. Pathophysiol. a. The process by which trabecubar bone is formed within lung tissue. b. The state in which trabeCUlar bone exists within the lung tissue. c. A mass orfocus of trabecular bone occurring in lung tissue. 2. Radio!. Cabciflc opac. ities within the lung that represent trabecular bone; applicable to disseminated calcific opacities that (1) display morphologic characteristics of frabectiar bone (i.e., trabeculation and a defined cortex) or, more often, (2) occur in association with a lesion known histologically to produce trabectilar bone within lung (e.g., mitral stenosis). -Synonyms: ossific nodulation, ossific nodube(s). -Evaluation: 2(i). A primary radiobogic diagnosis. 2(2). An inferred conclusion. In either case, a useful radiobogic term; to be distinguished from pulmonary calcification. ossified, adj. Having been changed into bone. ossify, v. To change into or form bone.

p parasplnal

line, n, -s. Radio!. A vertically oriented interface usually seen in a frontal chest radiograph to the left and rarely to the right of the thoracic vertebral column. It extends from the aortic arch to the diaphragm and represents contact between aerated lung (of a lower lobe) and adjacent mediastinal tissues. On the left, the

anatomic interface is situated posterior to the descending aorta, and its radiographic shadow is usually seen between the left lateral margins of the aorta and spine. -Synonyms: left paraspinal pleural reflection, left paraspinal interface. Evaluation: A specific feature in radiobogic anat-

omy. Either of the synonyms cited is preferred to paraspinalline, inasmuch as the shadow, in fact, represents an interface, not a line. parenchyma, n. 1. Anat. The gas-exchanging part

of the lung consisting

of the alveoli and their

capillaries, estimated to constitute about 90% of total lung volume. 2. Radio!. The lung exclusive

of visible pulmonary vessels and airways. Evaluation: A useful anatomic concept. An acceptable radiologic descriptor. -adj. parenchymatous. phantom tumor, n, -s. Radio!. The shadow produced by a local COlleCtiOn of fluid in one of the interbobarfissures, usually possessing an elliptical

configuration

in one projection

(e.g.. the lateral)

and a round configuration in the other (e.g.. the frontal view). It is commonly caused by cardiac decompensation and usually disappears after appropriate therapy. -Synonyms: vanishing tumor, pseudotumor. -Evaluation: A diagnostic conclusion that can only be inferred from a single radiograph, but may be explicit by the presence of serial radiographs. In the latter case, it is an acceptable radiobogic descriptor. plateilke atelectasls, n. Radio!. A linear or planar

SOCIETY

GLOSSARY

opacity of uncertain significance, presumed to represent diminished volume in part of the lung seen end-on. -Synonyms: platter, linear, or discold atelectasis. -Evaluation: An inferred conclusion, usually not subject to proof and often unwarranted. Its use as a descriptor is not recommended. Linear opacity, planar opacity, etc. are preferred. pleonemla, n. 1. Physiol. Increased blood flow to the lungs or a part thereof. 2. Radio!. General or local increase in the apparent width of visible

pulmonary vessels, suggesting

greater than nor-

mel blood flow. -Synonyms: hyperemia, increased blood flow. -Evaluation: An inferred conclusion appropriately based on the radiographic findings alone. Because pleonemia serves to distinguish increased blood flow of other causes from increased blood flow resulting from inflammation (hyperemia), it is the preferred term in this sense. -adj. pbeon.mlc. pneumatocele, n, -s. 1. Pathol anat. a. A thinwalled. gas-filled space within the lung, usually occurring in association with acute pneumonia (most commonly of staphybococcal origin) and almost invariably transient. b. A form of pulmonary air cyst. 2. Radio!. An approximately round, transient lucency within the lung that is usually associated with, arid adjacent to, a zone of resolving pulmonary consolidation that is presumed to represent a pneumatocele in the pathologic sense. -Evaluation: 2. An inferred conclusion. An acceptable descriptor only if used in accordance with the precise definition. pneumomedlastlnum, n. 1. Patho!. A state characterized by the presence of gas in mediastinal tissues outside the esophagus and tracheobronchial tree. 2. Radio!. The presence ofone or more gas shadows within the mediastinum that do not correspond in position and contour with gas in the esophagus or tracheobronchial tree. -Qua!ifiers: spontaneous, traumatic, diagnostic. Synonym: mediastinal emphysema. -Evaluation: A diagnostic conclusion appropriately based on radiologic findings alone. Pneumomediastinum is preferred to mediastinal emphysema. pneumonia. n, -s. 1. Pathol. Infection of lung parenchyma and/or interstitium. 2. Radio!. COnSOIidation or any ofvarious otherforms of pulmonary opacification presumed to represent pneumonia in the pathologic sense. -Synonym: pneumonitis. -Qualifiers: Expressing temporal course:

acute, chronic. Expressing type of pulmonary involvement: airspace, bobar, interstitial, broncho(pneumonia plus bronchitis). Expressing cause: bacterial, viral, fungal. mycoplasma. -Evaluation: An inferred conclusion; pneumonia is the preferredgeneric term. pneumoperlcardium, ni. Pathol. A state characterized by the presence of gas within the pericardial space. 2. Radio!. The presence of gas within the pericardium; visible only where the gas shadow is seen in profile: laterally in the frontal view, anteriorly or posteriorly in the lateral projection. -Evaluation: A diagnostic conclusion appropriately based on radiobogic findings alone. pneumothorax, n, -aces. 1. Pathol. A state characterized by the presence of gas within the pleural space. 2. Radio!. The presence of a gas shadow between the peripheral margin of the lung (visceral pleura) and the chest wall, ciaphragm, or mediastinum(parietal pleura). -Qualifiers: spontaneous, traumatic, diagnostic, tension. -Evaluation: A diagnostic conclusion appropriately based on radiobogic evidence alone. popcorn calcification, n. Radio!. A cluster of sharply defined, irregularly lobulated, calcific opacities suggesting the appearance of popcorn. -Evaluation: An acceptable descriptor. posterior junction line, n. Radio!. A vertically oilented, linear or curvilinear opacity about 2 mm

515

wide, commonly projected shadow and usuaNy slightly

on the concave

tracheal air to the right. it is produced by the shadows of the right and left pleurae in intimate contact between the aeratod lungs. It represents the plane of contact between the lungs posterior to the esophagus and anterior to the spine; hence, in contrast to the anterior junction line, it may extend both above and below the suprastemal notch and may be seen above and/or below the azygos and aortic arches. -Synonyms: posterior mediastinal septum, posterior mediastinal line. -Evaluation: A specific feature of radlologic anatomy. to be preferred to the synonyms. posterior tracheal stripe, n. Radio!. A vertically oriented, linear opacity ranging in width from 2 to 5 mm, extending from the thoracic inlet to the bifurcation ofthetrachea and visible only in lateral radiographs of the chest. It is situated between the air shadows of the trachea and the right lung and is formed by the posterior tracheal wall and contiguous mediastinal interstitial tissue. -Synonym: posterior tracheal band. -Evaluation: A specific feature of radiologic anatomy. Posterior tracheal stripe is preferred to posterior tracheal band. primary complex, n. 1. Pathol. The combination of

a focus of pneumonia produced by a primary mfection (e.g., tuberculosis or histoplasmosis) with granubomas in the dralnrng hilar or mediastinal lymph nodes. 2. Radio!. a. The combination of one or more irregular pulmonary parenchymal opacities of variable extent and location assumed to represent consolidation with enlargement of the draining hilar or mediastinal lymph nodes; an appearance assumed to represent an active infection. b. The combination of a small, sharply defined parenchymal opacity(often calcified) with calcification of the &alning hilar or mediastinal lymph nodes; an appearance usually regarded as evidence of an inactive process. -Synonyms: Rankecomplex. Ghon complex. Primary complex is to be preferred to Ranke complex, which is acceptable but rarely used, and Ghon complex, which represents an inappropriate use of the eponym and is unacceptable. -Evaluation: A

useful inferred conclusion. profusion, n. Radio!. I. A qualitative expression of the number of small opacities per unit area or zone of lung. 2. In the ILO/1980 classification of radiographs of the pneumoconioses. the quaIlflora 0 through 3 subdIvide the profusion of small rounded and small irregular opacities into four major categories. These may be further subdivided to provide a 12 point scale: -/0,0/0,0/1; 1/0,1/1,1/2;2/1, 2/2, 2/3; 3/2, 3/3, 3/k. pseudocavlty, n, -lee. Radio!. Any shadow cornplex that has the appearance of a gas-containing spacewithin a zoneofconsolidation, a pulmonary mass, or a nodule when, in fact, no such space

exists; hence: 1. A central lucency within a nodule or mass that is proved by computed tomography or pathologic examination to represent lipid. 2. An apparently circumscribed lucency created by the confluence of shadows of normal anatomic structures, most commonly ribs and pulmonary vessels, that does not, in fact, represent a cavity. -Synonyms: 2. composite shadow, spurious cavity. -Evaluation: 1. An inferred conclusion, sometimes used as a descriptor. The term is

without causative connotation.

Its use is not rec-

ommended. pulmonary blood flow resthbution, n. 1. Physiol. Any departure from the normal distribution of blood flow in the lungs, whether physiologic or pathologic. 2. RadiO!. Narrowing and reduction in the number of visible pulmonary vascular shadows in one or more lung regions associated with corresponding widening and increase in the numbar of Visible pulmonary vascular shadows in the

516

FLEISCHNER

remaining lung regions. -Evaluation: An inferred conclusion, often used as a descriptor and appropriately based on radiographic evidence alone. pulmonary edema, n. 1. Pathophysiol. The accumulation of fluid in the interstitial compartment of the lung with or without associated alveolar filling. Specifically, the accumulation of water, protein, and solutes (transudate) usually due to (1) ricreased pressure in the microvascular bed; (2) increased microvascular permeability; or (3) impaired lymphatic drainage. Also, the accumulation of water, protein, solutes, and inflammatory cells(exudate)in response to inflammation of any type (e.g., infection, hypersensitivity, trauma. or circulating toxins). 2. Radio!. An inferred conclusion applicable to a pattern of opacity (often bilaterally symmetric and perihibar in distribution) believed to represent alveolar filling and/or interstitial thickening when associated findings and/ or history suggest one of the processes enumerated above. ualifiers: I. Interstitial edema: pulmonary edema confined to the interstitial cornpartments of the lung; initially the bronchovascuber interstitial space and its continuum, subsequently the alveolar wall interstitial space. Alveolar edema: pulmonary edema involving the alveoli as well as the interstitial space. Synonyms: 2. Wet lung, boggy lung. moist lung. drowned lung. -Evaluation: An inferred conclusion often used as a descriptor. A useful and acceptable term when used in an appropriate clinical setting. The synonymous terms are colloquialisms to be avoided. pulmonary perfusion, n. 1. Physiol. The passage of blood through the vessels of the lung or a part thereof. 2. Radio!. Any radiologic evidence of pulmonary blood flow in the physiologic sense. It

may be explicit (in the case of pulmonary angiography) or inferred (in the case of conventional radiography). -Synonym: pulmonary blood flow. -Evaluation: a physiologic conclusion that can properly be based on, or inferred from, radiobogic evidence

alone.

A useful and recommended

term.

R radiographic contrast, n. Radio! phys. 1. The difference in optical density between two specified shadows (usually adjacent) in a processed radiograph. 2. The resultant of film contrast and subject contrast. -Evaluation: A fundamental concept of radiologic physics, useful in a clinical context as one determinant of radiographic qualIty.

radiographic quality, n. 1. Radio!. An expression of the acceptability of a diagnostic radiograph to the interpreter; a subjective evaluation. 2. Radio! phys. An expression of the correspondence between the physical characteristics of a radiograph and some predefined standards, usually with respect to contrast, resolution, and density; an objective evaluation. -Synonym: film quality. Evaluation: A useful concept, but only in a loose, qualitative sense. The term defies precise quantitative definition and is not in either sense an

expression diograph.

of the diagnostic

usefulness

of a ra-

radlologic sign, n, -s. Radio!. A shadow or shadow complex said to be reliable evidence of a specific pathologic state, process, or relation. A list (in-

complete) of specific signs, their reputed significance, and their reliability is as follows: broken bough 5.: peripheral bronchial occlusion (highly unreliable). camabote 5.: echinococcus cy5t (reliabbe). continuous diaphragm s.: pneumomediastinum (usually reliable). crescent 5.: intracavitary

mass; hydatid cyst, fungus ball, etc. (reliable cvidence of an intracavitary mass but not specific with respect to cause). gloved finger s.: bron-

SOCIETY

GLOSSARY

chiectasis (usually reliable). hibar bifurcation 5.: vascular vs. extravascubar hilar enlargement (urnited usefulness). hllum overlay 5.: cardiomegaly vs. antenormediastinal mass(limited usefulness). melting Ice s.: pulmonary infarction (limited usefulness). moon 5.: see crescent a. 1-2-3 s.: pulmonary sarcoidosis (unreliable; misleading). rabbit ear s.: bronchioboalveolar cell carcinoma (unreliable). scimitar s.: partial anomalous pubmonary venous return (reliable). sIlhouette s.: presence and localization of intrathoracic lesion (reliable). tall 5.: see rabbit ear s. (unreliable). water lily 5.: see camabote s. (reliable). Westermark s.: pulmonary embolus(usually reliable). Evaluation: Signs are seldom as specific as their authors believe, and their meanings are often confused through frequent misuse. Many are unreliable(e.g., rabbit ear)or totally erroneous (e.g.,

1-2-3 sign of sarcoidosis). With the exception of a few generally recognized and usually reliable signs (scimitar, silhouette, Westermark), the use

of signs as

descriptors is not recommended. description of the individual finding

Specific is preferred. residual, n. Radio!. Any nonspecific opacity of uncertain cause believed to represent an inactive process. -Synonym: scar. -Evaluation: An intermed conclusion. The term is vague, grammatically incorrect (residuum is the noun), and should be rejected in favor of more precise diagnostic statements. -adj. Of or pertaining to a residue or remainder. resolution, n. 1. Radio.! phys. a. A quantitative expression of the number of punctate or linear absorbers that can be recorded as perceptibly discrete shadows per unit distance across a radiographic receptor; usually expressed in line pairs per millimeter. (Metallic wires are usually used as test objects for such measurements.) b. The characteristic of a radiographic receptor systern that expresses its ability to record closely approximated absorbers as discrete shadows. c. The spatial frequency response of a radiographic system, usually expressed in terms of its moduladen transfer function (MTF). d. A measure of the “fidelity of the imaging system. -Synonym: resolving power. -Evaluation: Resolving power is technically the correct term, but by virtue of bong usage, resolution is acceptable in this sense. 2. Pathol/Radiol. The process by which a lesion, specifically aconsolidation, clears. It may becomplete or partial. -Evaluation: An explicit diagnostic statement appropriately based on serial radiographs. respiratory failure, n. Physic!. A pathologic state resulting from impaired respiratory function and characterized by an arterial Po below 60 mm Hg or an arterial Pco above 49 mm Hg, in a subject at rest at sea level. -Qualifiers: acute, chronic. -Synonym: pulmonary insufficiency. -Evaluation: A useful term in its clinical and physiologic usage that should never be used as a radiobogic descriptor. It is preferred to pulmonary insufficiency. retbcular pattern, n, -s [usually in the singular]. Radio!. A collection of innumerable small linear opacities that together produce an appearance resembling a net. -Qualifiers: fine, medium, coarse. -Synonym: Small irregular opacities (in the lLO/1980 classification of pneumoconioses). -Evaluation: A recommended descriptor. It has no pathologic connotation and should not be used as a synonym for interstitial disease of the lung. The synonymous term smallirregular opecities should be restricted to the radiographic characterization of pneumoconiosis. reticubonodular pattern. n, -s [usually in singular]. Radio!. A collection of innumerable small, linear and micronodularopacities that together produce a composite appearance resembling a net with

AJR:143,

September

1984

small superimposed the reticular and sionally of similar

nodules. In common usage, nodular elements are dimenmagnitude. -Qualifiers: fine,

medium,

-Evaluation:

coarse.

An acceptable

radiobogic descriptor without specific pathologic wnplications. righttracheal stripe. n. Radio!. A vertically oriented linear opacity 2-3 mm wide that extends from the thoracic inlet to the right tracheobronchial angle in the frontal radiograph. It is situated between the air shadow of the trachea and the right lung and is formed by the right tracheal wall and contiguous mediastinal interstitial tissue and adjacent pleura. -Synonyms: right paratracheal stripe or band. -Evaluation: A specific feature of radiographic anatomy.

S segment, n, -s. Anat/Radiol. One of the Principal anatomic subdivisions of the lobes of the lung (usually 10 on the right and 9 on the left); a lobar subdivision served by a major branch of the bobar bronchus. -Qualifier: bronchopulmonary. segmental, adj. Mat/Radio!. Of or pertaining to a segment. septal line, n, -s [usually in the plural]. Radio!. A generic term for fine, linear opacities of varied distribution produced by the interstitium between pulmonary lobules when the interstitium is thickened by fluid, dust deposition, cellular material, etc. -Synonyms: Kerley lines (q.v.), lymphatic lines; of. interlobar septum. Septa! lines is the preferred term; Kerley lines is acceptable, particularly when one seeks to identity a particular type of septal line (e.g., Kerley B lines). Lymphatic lines is anatomically an inaccurate term and should not be used in this context. -Evaluation:

A specific feature of pathologic radiobogic anatomy. often inferred. A recommended term. shadow, n, -s. Radio!. 1. In clinical radiography, any perceptible discontinuity in film blackening ascribable to the attenuation of the x-ray beam by a specific anatomic absorber or lesion on or within the body of the patient. An opacity or bucency. 2. A similar discontinuity in any other diagnostic visual representation of the remnant energy in an x-ray beam after its passage through the body of the patient (e.g.. a fluoroscopic image, a CAT display, etc). -Qualifiers: The term should always be qualified as precisely as possible with respect to size, contour, location, opacity (lucency), etc. -Evaluation: A useful and recommended descriptorto be used only when more specific identifiCatiOn is not possible. shaggy heart, n. Radio!. A heart whose border is partially effaced by multiple small, irregularly distributed opacities produced by any of several pathologic processes affecting the paracardiac parts of the lungs and/or pleura. -Evaluation: This term is an imprecise radiologic descriptor, to be used with caution. sIlhouette sign, n. Radio!. 1. The effacement of an anatomic soft-tissue border by consolidation of the adjacent lung or accumulation of fluid in the contiguous pleural space. 2. A sign of the conformity and, hence, of the probable adjacency of

a pathologic opacity to a known structure; useful in detecting and localizing a consolidation along the axisofthe x-ray beam. -Evaluation: A widely accepted and useful radiologic descriptor. It should be noted that the finding, in fact, involves the loss of a silhouette. small irregular opacity, n, -lee [usually used in the plural]. Radio!. 1. Small pulmonary opacities that defy classification in terms of simple geometric descriptors, that are often poorly defined, and that in large numbers produce an appearance

AJA:143,

FLEISCHNER

September1984

resembling

a

net. 2. In the ILO/1980 classification

of radiographs

of the pneumoconioses,

the qualiflers s, t, and u subdivide such opacities into three categories on the basis of their greatest thickness: s, up to 1.5 mm; t, I .5-3 mm; and u, 3-10 mm. -Synonym: reticular pattern. -Evaluation: A term to be used specifically to describe radiographic manifestations of the pneumoconioses. Reticular pattern is preferred when referring to nonpneumoconiotic disease. small rounded opacity, n, -lee [usually used in the plural]. Radio!. 1. Innumerable small pulmonary nodules ranging in diameter from bare visibllity

up to 10 mm. 2. In the lLO/1980

classification

of

radiographs of the pneumoconioses. the quailflersp, q, and r subdivide the predominant opacIties into three diameter ranges: p. up to 1 .5 mm; q, 1 .5-3 mm; and r, 3-1 0 mm. -Synonym: nodular pattern. -Evaluation: A term to be used specifically to describe radiographic manifestotions of the pneumoconioses. Nodular pattern is preferred when referring to nonpneumoconiotic disease. stripe, n, -S. Radio!. An extended longitudinal, cornposite opacity 2-5 mm wide; cf. line, band shadow, linear opacity. -Evaluation: An acceptable descriptor when used with reference to radiographic shadows within the mediastinum. subject contrast, n. Radio! phys. 1. Quantitative: The ratio of the intensities of the remnant radia-

(q.v.). -Evaluation:

differences

in

lesser order than a segmental bronchus, but which islarger than a lobule. subsegmental, adj. 1. Anat/Radiol. Of or pertaining to a subsegment. 2. Radio!. Of or pertaining to any pulmonary shadow, smaller than a segment and larger than a lobule, presumed to represent a subsegment in the anatomic sense. -Evaluation: An acceptable radiologic descriptor.

the

beam that will traverse the lungs of the patient in

ically unless thickened;

arterial walls, unless cal-

These qualifiers are, therefore, sential to their description. -Synonyms:

A common

from

descriptor,

the exposure of a frontal chest radiograph. tubular shadow, n, -s. Radio!. 1. Paired, parallel or slightly convergent linear opacities presumed to represent the walls of a tubular structure or dovice (e.g., a bronchus, vessel. or chest tube, seen in profile). 2. An approximately circular opacity presumed to represent the wall of a tubular structure or device seen en face. -Qualifiers: Bronchial walls are usually not identifiable radiograph-

ferent

resulting

A radiologic

use of which is not recommended. Linear opacities properly qualified with respect to size, location, and Orientation 5 tO be preferred. trough filter, n. 1. Radio! phys. Any x-ray filter traversed by a longitudinal zone of diminished thickness. 2. Radio!. An x-ray filter designed to attenuate preferentially those parts ofthe primary

cified.

absorbers

517

GLOSSARY

tramline shadow, n, -s [usually in plural]. Radio!. Parallel or slightly convergent linear opacities that suggest the planar projections of tubular structures and that correspond in location and oriontation to elements of the brOnchial tree. They are generally assumed to represent thickened bronchial walls. (Such shadows are of possible pathobogic significance only when they occur outside the limits of the hilar shadows where bronchial walls may be seen in the normaL) -Synonyms: thickened bronchial wails, tubular shadows

ben, including scatter, emerging from two spoolfled absorbers in the path of an x-ray beam. 2. Qualitative: The difference in attenuation of diftheir physical densities, effective atomic numbars, and path lengths. -Evaluation: A fundamental concept of radiologic physics. subse9ment, n, -s. Anat/Radiol. A unit of pulmonary tissue that is supplied by a bronchus of

SOCIETY

shadow, thickened

almost es-

tramline bronchial wall. -Evaluation:

radiobogic descriptor, but dearly a misnomer to be avoided. Shadow of a tubular structure is acceptable if the anatornic significance of a shadow is truly obscure; otherwise, thickened bronchial wail or Calcified arterial wail is to be preferred. turner. n, -s. 1. A swelling or morbid enlargement. 2. Pathol anat/Radio!. Literally, a mass. -.Synonym: mass. -Evaluation: A useful descriptor. Mass is preferred. The term does not differentiate between a neoplastic and a nonneoplastic mass; its use as a synonym for neoplasm is to be condemned.

T

V

tension, adj. 1. The state of being stretched or strained. 2. Physiol/Med. A state characterized by cardiorespiratory functional impairment caused by pneumoor hydrothorax. 3. Radio!. The accumulation of gas or fluid in a pleural space in an amount sufficient to cause compression of the ipsilateral lung, markedly enlarge the hernithorax, depress the hemidiaphragm, and displace the medistinum to the opposite side; applicable only in the presence of clinical cardiorespiratory embarrassment. -Evaluation: An inferred conclusion to be used only as specified in the definition. In fact, tension in relation to pneumothorax

Valsalva maneuver, n. Physiol. Forced expiration against a closed glottis, usually but not necessarily from a position of total lung capacity. A maneuver used to produce transient increase in intrathoracic pressure. vascular prominence, n. Radio!. Real or apparent increase in the caliber and/or number of pubmonary vessels beyond the expected range, which, in view of the wide range of normal, does not necessarily imply a pathologic departure from normal. ynonyms: increased vascularity, vascular engorgement, pulmonary hyperemia, putmonary plethora, pulmonary pleonemia. These terms all represent inferred conclusions and are not, therefore, strictly synonymous with vascular prominence. Each is applicable only in specified circumstances and each must be used with care. -Evaluation: The term vascular prominence is

exists only during the expiratory phase of the respiratory cycle, since pleural pressure on inspiration is usually subatmospheric. The word should not be used in the term tension cyst, which does not satisfy the criteria cited above.

an acceptable radiologic descriptor. vasoconstrictlon, n. 1. Physio!. The narrowing of a muscular blood vessel by contraction of its musole layer. 2. Radio!. Local or general reduction in the caliber of visible pulmonary vessels that is presumed to result from decreased blood flow produced by contraction of muscular pulmonary arteries. -Qualifiers: hypoxic, reflex. -Antonym: vasodilation. -Evaluation: In the interprotation of conventional radiographs, an inferred conclusion appropriately based on radiographic signs that are usually reliable. In the interpretation of angiograms, an explicit radiographic conclusion. The term is not synonymous with oligernia. Oligerniais a sign ofvasoconstriction, a functional and potentially reversible process; it also applies to wreversible vessel narrowing. as in emphysome. vasodllatatbon, n. 1. Physiol. The widening of the lumen of a muscular blood vessel by relaxation of its muscle layer. 2. Radio!. The local or general increase in the width ofvisibbe pulmonary vessels resulting from increased pulmonary blood flow -Synonym: vasodilation. -Evaluation: In the interpretation of conventional radiographs, an inferred conclusion to be expressed with caution, since apparent widening of pulmonary vascular shadows may. in fact, be due to perivascular edema, neoplasm, etc. In the interpretation of angiograms, an explicit conclusion. ventilate, v. Physiol. I. To circulate air into and out of any closed space. 2. Specifically, to introduce fresh air and expel stale air from the lungs by physiologic or mechanical means. 3. To provide with a patubous opernng for the circulation of air. -Qualifiers: hyper-; hypo-. ventilated, adj. 1. Having had fresh air admitted and stale air expelled by physiologic or mechanical means. -Qualifiers: hyper-; hype-. ventilation, n. Physio!/Radio!. 1. The dynamic acts of inhaling fresh air and exhaling stale air. 2. The movement of air into and out of the lungs. 3. Inspiration and expiration. -Qualifiers: hyper(preferred) or over- ; hype. (preferred) or under-. -Synonyms: breathing. respiration; cf. aeration, inflation. 4. Physic!. Oxygenation of the blood, specifically in the act ofrespiration. -Evaluation: A useful term if properly used. The term always wnplies a blphasic dynamic process of admission and expulsion; hence, cannot be assessed from a single static image. Not to be used synonyrnously with aeration and inflation.

x x-ray quality, n. Radio! phys. The effective energy or spectral distribution of an x-ray beam. 1. Usually expressed in terms of half-value layer (HVL) in mm of aluminum. 2. Often implied, but not explicitly defined, by a statement of the peak voltage applied to the x-ray tube. -Synonym: xray beam quality. -Evaluation: A fundamental

physical measurement

useful clinically in spool-

lying and comparing radiographic systems and techniques. The practice of expressing x-ray quality in terms of beam hardness is to be avoided.