Abdominal Emil

J. Balthazar,

Richard

B. Gordon,

MD MD

Closed-Loop Intestinal

Bernard A. Birnbaum, #{149} Charles A. Whelan,

#{149}

and

Gastrointestinal

and MD MD

Alec Donald

#{149}

J. Megibow, H. Hulnick,

#{149}

Radiology

MD MD

Strangulating

Obstruction:

CT Signs’

In 19 patients with closed-loop intestinal obstruction, including 16 patients with strangulating obstruction, the findings

at examination

with (CT) were retrospectively correlated with the surgical and pathologic findings and evaluated by two radiologists. Signs of closed-loop obstruction, present in 15 patients, were associated with the configuration of the incarcerated loop of small bowel, abnormalities detected at the site of obstruction, or both. These abnormalities were the following: a U-shaped, distended, fluid-filled bowel loop; the whirl sign; the beak sign; a triangular loop; two adjacent collapsed loops of bowel at the site of obstruction; or all of these. CT signs of strangulation, seen in 10 of the 16 patients with

computed

ischemic

tomography

or infarcted

bowel,

were

associated with the appearance of the bowel wall (thickening, high attenuation, and the target sign), abnormalities in the attached mesentery, or both. In mechanical obstruction of the small bowel, detection of ischemic changes in the bowel wall or mesentery with CT indicates strangulation. Absence of CT findings of ischemia or infarction does not rule out strangulation. Index terms: Computed tomography (CT), clinical effectiveness #{149} Intestines, CT, 74.1211 Intestines, stenosis or obstruction, 74.723 Radiology

1992;

185:769-775

I From the Department York University-Bellevue

First

AIM.,

Ave.

New

R.B.G.);

Mountainside

of Radiology, New Medical Center, 550 York, NY 10016 (E.J.B., B.A.B., Department of Radiology,

Hospital,

Montclair,

NJ (C.A.W.);

and Department of Radiology, Danbury Hospitab, Danbury, Conn (D.H.H.). Received December 19, 1991; revision requested January 23, 1992; final revision received May 26; accepted June 29. Address reprint requests to E.J.B. C RSNA, 1992 See also the editorial by Wills (pp 635-636) in this

issue.

b.

a. Figure

1.

points

of adjacent

volvulus.

Diagram Twisting

of the incarcerated

of closed-loop

segments

obstruction.

of bowel.

of the closed

loop

(a) Adhesive

(b) Closed-loop (volvulus)

band

obstruction

is a common

causes

obstruction

associated

at two

with small bowel

but not invariable

complication

loop.

T

HE frequency of strangulating obstruction in patients with obstruction of the small bowel varies in

experienced The presence

different studies from 5% to a maximum of 42%, with an average of approximately 10% (1, 2). Early recognition of this abnormality remains crucial in the decision whether to use surgical or medical management in these patients. Although the overall mortality rate in simple obstruction of the small bowel has been reduced to 5%-8% (3-7), it still is markedly higher (20%-37%) in patients with strangulating obstruction (3-9). Extensive clinical experience has shown that differentiation between simple and strangulating obstruction is not feasible with conventional clinical findings, laboratory findings, or

operatively in 50%-85% with surgically proved

struction

(2,8,10-14).

clinical judgment of strangulating

could

Many

not

be

(1-7). ob-

diagnosed

pre-

of patients strangulation

of these

studies

in-

cluded plain abdominal radiographs as part of the preoperative evaluation. While plain abdominal radiographs may be occasionally helpful (15,16), they often exhibit only a pattern of obstruction or may be deceptively normal and misleading (12-14,17,18). A few case reports (19-23) have shown the potential usefulness of computed tomography (CT) in diagnosis of closed-loop obstruction. To our knowledge, a comprehensive analysis of the CT findings in a larger group of patients has not been pub769

lished.

It is the purpose

of this report

to (a) analyze the CT features of closed-loop obstruction, (b) describe the expected CT findings of strangulating obstruction, and (c) determine the potential usefulness and limitations of CT in the evaluation of pa-

tients ing

suspected

of having

strangulat-

obstructions. BACKGROUND

A closed-loop or incarcerated small bowel loop is a form of mechanical intestinal obstruction in which a segment of bowel is occluded at two points along its course (Fig 1). The sites

of obstruction

each

other.

are

They

adjacent

to

are the result

of a

single constrictive lesion that occludes the intestine and affects the attached small bowel mesentery in the process. The length of bowel involved varies from a single loop to longer segments that contain several loops of bowel. The pinching effect of two adjacent

segments

of bowel

mesentery attachment

loop.

This

closed

anatomic

configuration is a setup for the closed loop to rotate (twist) along its long axis and thereby produce a small bowel volvulus (Figs 1, 2). The subsequent impediment to the mesenteric

vascular

supply

causes

bowel

anoxia

and development of ischemia and bowel necrosis. By far the most common causes of strangulating obstruction of the small bowel are adhesive bands (Fig 1) and internal or external hernias. Primary

small

bowel

volvulus,

without

genital midgut malrotation structive lesion, is a common emergency in some African countries but is rarely seen

America (21). Strangulating

obstructive

associated

intestinal

with

During

cular

surgical

is characterized

lack of peristalsis, infarction

severity

and

and

duration

and mesenteric determines the

ment

and

the

bluish dispulsations, hemor-

and

eventual The

of the intestinal

obstructive potential

severity

vas-

by

perforation. process develop-

of complications.

It should be stressed that although incarceration (closed loop) and strangulation (ischemia) are related phenomena, they are separate pathologic

entities.

Many

development 770

Radiology

#{149}

intermediate exist

between

stages

Closed-loop enables

loop,

obstruction detection

incarceration

with

of two

small

distended

of

a partially

(closed

loop) may not be associated with strangulation and may spontaneously resolve. On the basis of these basic anatomic and pathologic considerations, the expected CT findings in this entity can be divided into two distinct categories: those associated with closedloop obstruction and those diagnostic of strangulating obstruction. CT findings in closed-loop obstruction are the following: (a) evidence of small bowel obstruction; (b) a U-shape configuration, radial distribution of fluid-filled dilated loops, and mesenteric vascular structures that converge toward the point of obstruction; and (c) a site of obstruction with a whirl sign, beak sign, triangular loop, or two adjacent collapsed loops at the site of obstruc-

bowel

volvulus.

fluid-filled

A transverse

segments

the loops of bowel (bottom right).

loop obstruction

imaged

collected

findings with

of closed-loop CT appearance tation of the loops, degree

the

CT

diagnosis

obstruction (Fig 2). The depends on the orientwo adjacent compressed of obstruction, presence

strangulating

presented

nausea, of haying intestinal obstructions. CT examinations were performed to either confirm the

clinical

suspicion

suspected

or evaluate

the intraab-

dominal disease. Our study group consisted of 12 women and seven men aged 40-81 years (mean age, 63 years). Surgery was performed 2-40 hours after the CT examination.

gone

Sixteen

patients

laparotomy,

from

this study

examination,

radiologic

examinations

radiographs

and

spectively

reviewed

radiologists

(E.J.B.,

ered characteristic chanical intestinal and

sults

reflects

servers. correlated

The

by means

CT, or both. (plain

CT

scans)

and

were

strangulating

a consensus

retro-

by two

Signs

or suggestive obstruction,

The

abdominal

analyzed

B.A.B.).

The data

consid-

of meclosed-loop obstruction

presented of the

in Retwo

ob-

radiologic abnormalities were with the surgical and patho-

logic findings. All patients contrast

had

because

diagnosed

of clinical

recorded.

under-

trauma with a rent in caused internal hernia. and strangulating by external hernias

are easily

were

had

and one patient

previous abdominal the mesentery that Cases of closed-loop obstruction caused

obstruction,

establishes

6 years

distention,

and were

ness

struction

past

and pathologic

Patients

pain,

and vomiting

excluded

fluid

CT. Our ma-

the

and

obstructions.

cases

or mesenteric

during

abdominal

of closed-

with

of closed-loop

intestinal

evaluation

cases

of the surgical

such

(congestion),

METHODS

proved

were

(hemorrhage) in the attached small bowel mesentery. The appearance of the incarcerated loop and/or specific findings visualized at the site of ob-

AND is a retrospective

was

to each

and thickness (Fig 2).

This study

terial

right).

adjacent

of 19 consecutive

on the basis

of the

(top

are collapsed

MATERIALS

ob-

in strangulating

section

of intestine

of volvulus, and level of the CT cross section

struction are the following: (a) evidence of small bowel obstruction; (b) slight circumferential thickening, high attenuation, a target sign, or pneumatosis in the wall of the incarcerated bowel; and (c) engorged mesentenc structures, mesenteric hazi-

tion. CT findings

ischemia.

signs of anoxia, including coloration, loss of arterial subserosal and mesenteric frank

is defined process

examination,

compromise

rhage,

a conor an obsurgical and Asian in North

obstruction

as an intestinal

loop

closed loop and a complete obstruction, as well as between mild ischemia with viable bowel and frank necrosis. Furthermore, while strangulated obstruction develops secondary to a

at the root of the

intestinal

2.

closed

At the level of the obstruction and volvulus, other or may exhibit a triangular configuration

causes a narrow base of and a long, mobile, ob-

structed

Figure

material,

received and

orally 17 of the

administered 19 patients

examined received intravenously administered contrast material. A bolus of 50 mL of 43% iodinated contrast material was December

1992

Figures

3, 4.

(3) Obstruction

caused

graph is nonspecific, with a few of small bowel (1) with a slightly

a finding

consistent

with

by strangulated

air-filled thickened

mechanical

jejunal wall

intestinal

small

loops (open

bowel

secondary

to adhesions

and air in the stomach arrows) and a U-shape

obstruction.

The attached

and colon. configuration.

mesentery

(solid

in a man

aged

69 years.

(a) Plain

(b) CT scan shows a distended, Distal ileum (arrowhead)

arrow)

has increased

abdominal

fluid-filled is completely

attenuation,

with

radiodistal loop collapsed,

complete

obliteration of the mesenteric vascular markings. Surgery revealed mesenteric hemorrhage and intestinal infarction. (4) Obstruction in strangubated small bowel produced by adhesions in a woman aged 79 years. (a) Plain abdominal radiograph shows a poorly defined soft-tissue mass (pseudotumor) in the left flank (arrows) that is suggestive of strangulation (S ). (b) CT scan obtained at the same level as in a shows distended fluid-filled loops of bowel, seen in the longitudinal plane (b) and cross section (arrow). The attached mesentery (M) has high attenuation, with poor definition of engorged vascular markings. Surgery revealed mesenteric hemorrhage, and 50 cm of infarcted bowel was resected.

given tional

at 1.5 mL/sec, 140 mL at 0.8

15-mm

collimation

tients,

10

mation 5-mm region

end

was

x 12-mm

five patients,

followed mL/sec.

and

by an addiInitial 10 x

used

initial

in seven

collimation

10 x 10-mm

initial

Volume

185

in eight

Number

#{149}

patients.

3

radiographs

were

reviewed

all patients.

was

and RESULTS

colli-

Plain

in

Surgical

diagnosed

infarction

pain

in seven patients. Repeated 5 x or 5 x 8-mm collimation over the of interest was performed at the

of the study

abdominal

Findings

All patients had closed-loop obstruction. Strangulating obstruction

in 16 patients. was

ischemic

patients.

The

found

but causes

Bowel

in 12 patients,

viable

bowel,

in four

of incarcerated

obstruction in this group of 19 patients were as follows: adhesions, 14 patients; internal hernia, four patients; and primary intestinal volvuRadiology

771

#{149}

lus,

one

closed

patient.

loop,

sion

In addition

a variable

(volvulus)

was

similar present

to the

degree found

of tor-

mal

in all 19

degrees of distention were in the loops of bowel proxi-

to the

incarceration.

the closed loop almost completely

patients.

was

were

detected

in seven

patients

(Figs

10, 11).

In all cases,

completely filled with

or fluid

Strangulating

Obstruction

Plain abdominal radiographs revealed a pattern of obstructive small bowel in 10 patients, unremarkable or

while proximal intestinal loops contamed large amounts of air (Figs 4, 6). At the site of obstruction, fusiform tapering in the longitudinal section (the beak sign) was seen in two pa-

present in 10 of the 16 patients with proved ischemic changes at surgery (Table 2). Slight circumferential thickening of the bowel wall with high

nonspecific

findings

tients

attenuation

(Fig

the

Radiographic

Findings

3), and

in eight

sign

suggestive of closed-loop in one patient (Fig 4). In all cases, CT showed

pattern

of small

characterized

filled

bowel

obstruction a typical

obstruction

by distended,

proximal

loops

Loop

(Figs

bowel,

obstruction

or several

signs

of the CT

tients,

sponding section)

point

vessels

small

The incarcerated tended 3-5 cm, but

bowel

6)

Sign =

2)

Shape (n =

Whirl (n

4)

Sign =

Two Collapsed Adjacent Loops

2)

(n = 7)

+ +

+

+

+ +

+

+

-I-

+

+

+ .4+ +

+

12

13 14 15 16 17 18 19

toward

(Fig 5), or loop in most

=

Triangular Beak (n

+ +

9 10 11

(in cross thickened

converging

(n

7 8

distended configuration section), a corre-

of obstruction

both.

(Table one

were not seen 1). In 10 pa-

radial distribution with stretched and

mesenteric the

had

Radial

Distribution (a = 8)

1 2 3 4 5 6

19 patients

the incarcerated

was seen as fluid-filled loops with a U-shape (Fig 3b) (longitudinal

or halo (25)

Obstruction

Configuration

No.

of closed-loop

obstruction, such signs in four patients (Table

target patients

or

of closed-loop

who underwent examination 1). Although most patients sign

pa-

(Fig 6) and intestinal pneumatosis in one patient. Moderate to severe mesenteric congestion and hemorrhage

sign (23) was pres(Fig 9), and two loops of bowel

U-Shape

in 15 of the

in five

(Fig 8). The whirl ent in two patients adjacent collapsed

Table 1 Signs of Closed-Loop

signs

detected

with colon,

evaluation

revealed

was

were

tients (Figs 3b, 7). The sign was seen in three

Obstruction

Retrospective

a corresponding

of strangulation

triangular configuration in cross section was detected in four patients

Patient

findings

6, 7), and

signs

fluid-

associated

collapsed distal small both (24) (Fig 3). Closed

patients

pseudotumor

CT

was dispatients

+ +

+ +

+

+

+

+

+

+

+

6.

5.

Figures

5, 6.

(5) Strangulated

obstruction

produced

by primary

small

bowel

volvulus

in a man

aged

46 years.

This

CT scan

shows

the radial

distribution of several distended and fluid-filled bowel loops (open arrows). Note the slightly engorged and stretched mesenteric vascular structures (solid arrow) converging toward the point of torsion. No mesenteric hemorrhage is present. The closed bowel loop was ischemic but still viable, and resection was not performed. (6) Strangulated obstruction due to adhesions and volvulus in a woman aged 78 years. This CT scan reveals the fluid-filled closed loop (c) and the three concentric rings of high and low attenuation of the bowel wall (target sign) that affect

one intestinal closed (beak

772

loop sign).

segment At surgery,

Radiology

#{149}

(open

(c). The afferent the

arrow). Note the discrepancy between the distended but mainly air-filled proximal and efferent limbs of bowel leading into the site of torsion (solid arrow) are tapered incarcerated

bowel

was

slightly

ischemic

but

intestine and the fluid-filled and adjacent to each other

viable.

December

1992

that

selectively

tion

of the involved

affected

the

closed

detected

gery. Slight wall thickening, the target sign, and engorgement of mesentenc vessels correlated with mild ischemia

distribu-

bowel

loops

were

These ment

findings consist of engorgeof mesenteric vessels with in-

creased normal

haziness mesenteric

or total caused

obliteration

in six patients.

and blurring structures

of mesenteric

by hemorrhage All patients with

gulation

had

of the (Fig 4b)

(Fig

fat

and viable tenuation

bowel, while increased atof the bowel wall, pneuma-

tosis, and mesentery

hemorrhagic were seen

changes

in the

in patients

with

severe ischemia and infarction. In this retrospective analysis of 19 cases, CT enabled detection of signs of closed loop in eight patients, signs

3b).

CT signs of stranischemic changes at sur-

indicative

of closed

mechanical

2 of Strangulating

intestinal

Patient No. 1 2

+

3 4

+

Thickened Bowel Wall (n

=

(n

=

Sign 3)

+ +

Mellins’s Intestinal Pneumatosis (n = l)t

Ascites (n = 9)

+

in the clinical Plain abdominal

+

sometimes

+

only

+

11

+

12 13 14 15

+

+

+ + +

+

16

+

17

+

18 19

+

+

+

+

+ +

radiographs

revealing

one

by

bowel

the

+

+ +

fixed

+

+

of the

fluid-filled

loops

and

attached

with

closed-loop

been

exhibited

which is sug(Fig 4a). In soft-tissue by a grossly

closed

loop

but

of multiple

the congested

mesentery

Maglinte et al (24) scribed and analyzed features of enteroclysis

at surgery.

help

or deceptively In our study,

19 patients

conglomeration

orrhagic

to

but have

the pseudotumor sign, gestive of strangulation

+

article

differential diagnosis. radiographs are

to be nonspecific in most patients.

distended,

+

=

7.

classic

findings in stranintestine (15) usefulness of

this patient, the visualized mass was produced not + +

present, = absent. 4, 9, 13, and 16 had viable 10 had free air.

2).

Rigler’s

abdominal

found normal +

and

scout

-

+

obstruction

(Table

radiographic of the small the potential

+

-

+

on the gulation defined

+ +

-

10

Note.-+ * Patients t Patient

Target

5)

Congestion and Hemorrhage (n = 6)

+

6 7 8 9

strangu-

DISCUSSION

+

5

changes

Obstruction Mesenteric

lschemia at Surgery (n = 16)*

and

were seen (Tables 1, 2). The attenuation values of the intraluminal fluid did not help in the differential diagnosis. Free peritoneal fluid was present in eight of the 16 patients with proved bowel ischemia as well as in one of the three patients without ischemic

Table Signs

loop

lation (ischemia) in seven patients, and strangulation alone in two patients. In two patients, only signs of

and

hem-

(Fig 4b).

recently dethe radiologic in patients

obstruction.

Their

8.

Figures

7, 8. (7) Strangulated obstruction due to adhesions after right hemicobectomy was performed in a man aged 62 years. Examination with CT was performed without intravenous administration of contrast material. A fluid-filled bowel loop shows fusiform tapering (the beak sign) (B). Fluid-fibbed loops of bowel are distended and have a highly attenuated intestinal wall (arrows). Hemorrhagic blood (H) is seen in the mesentery. Hemorrhagic infarct was found at surgery, and 30 cm of bowel was resected. The scale at left indicates centimeters. (8) Closed-loop obstruction and volvulus due to adhesions in a man aged 50 years. CT scan shows the radial distribution in cross section of dilated intestinal loops (i) and a normal attached mesentery (m). At the torsion site, the collapsed afferent limb (arrow) is filled with fluid and has a triangular configuration. The adjacent efferent limb (arrowhead) is filled with residual barium from a barium enema administered before examination with CT. The small bowel was viable at surgery.

Volume

185

Number

#{149}

3

Radiology

S

773

Figure

9.

struction 79 years.

CT scan shows to adhesions

due The

strangulating in a woman

incarcerated

intestinal

obaged loops

a.

b.

(i) are mainly fluid-filled. The whirl sign (arrow) is represented by the tightly twisted

Figure 10. Closed-loop obstruction due to internal hernia through mesentery in a man aged 51 years. (a) CT scan shows the fluid-filled, loops (o in a and b). At the site of obstruction, the collapsed afferent

mesentery

seen

ment.

around

a collapsed bowel segpneumatosis and free air in cavity were also detected. Sur-

Intestinal

the peritoneal gery revealed

bowel,

intestinal

volvulus with perforation,

gangrenous and peritonitis.

study included cases of external hernia and exclusively analyzed findings

in patients

with

partial

small

bowel

obstruction, none of whom had strangulation. The detection of a complete closed-loop obstruction and of strangulation (ischemia) by means of barium studies is at best questionable and remains to be proved. The substantial contribution of CT to the diagnosis and evaluation of patients with bowel obstruction has been recently documented (26). Because it enables detection of bowel obstruction and depicts the bowel wall and the attached mesentery, CT is

best suited

for diagnosis

and

evalu-

ation in patients suspected of having strangulating obstruction. The CT findings are associated with the pres-

ence

of a closed-loop

obstruction

to the development of strangulation (see Background). In addition to the configuration the incarcerated loop previously

scribed

in closed-loop

and

obstruction

(19-21), a careful survey for the site of obstruction can often establish the diagnosis. The collapsed loops leading into the site of torsion can be seen on CT scans. These loops are adjacent to each other and sometimes have a figure 8 configuration. They are located usually at the root of the mesentery close to the fluid-filled, distended

incarcerated

loop

and

are isolated

without other adjacent collapsed loops of bowel (Figs 10, 11). Depending on the site and thickness of the section and the orientation of the collapsed loops, CT can enable detection of a whirl configuration (Fig 9); the 774

Radiology

#{149}

seen

proximal

(arrow). to the

(b) Adjacent

torsion

beak sign in the efferent loop, afferent loop, or both (Figs 6, 7); or a triangular configuration of the collapsed loop (Fig 8). The triangular loop, the crosssection equivalent of the beak sign, is usually seen adjacent to another collapsed loop of bowel (Fig 8). In this study, signs of closed-loop obstruction were seen in 15 of the 19 patients (Table 1).

site

cross

(arrow).

emphasized, spective control reliable ings

should

lar structures was

appeared

blurred, detected,

curred had surgically tion that necessitated

hazy,

the

vascu-

mesenteric or all of these

oc-

proved infarcintestinal resec-

tion (Figs 3, 4). These observations are in agreement with the known limitations of CT in detection of bowel ischemia; on the other hand, they reflect the high specificity of CT in diagnosis of strangulation whenever these signs are present in patients with small bowel obstruction. Our data, like previously reported data on bowel ischemia (27-29), indicate that the long period of time between examination with CT and surgical exploration (2-40 hours) makes precise correlation impossible. Because infarction can develop in only a few hours, CT may be more accurate if examinations are performed just before surgical exploration. Furthermore, the improved

the

with

via-

high-resolution

however,

It is conceivable

signs with

our retro-

bowel

ischemia,

some

of

or intramural

Adequate

cal correlation, dence of small

history,

clini-

and unequivocal bowel obstruction

be present

noses

that

might be present in pasegmental inflammatory

hemorrhage.

intestinal

basis

that

CT evaluation did not have a group. We do not know how or how specific these CT find-

are.

strangulation

mesentery

the two collapsed volvulus

(ie, use of an intravenous 5-mm collimation) now in use have improved our CT accuracy in this group of patients. It should be

lesions,

of isch-

and

defect in the small bowel limbs are

technique bolus and

ischemic changes that affect the bowel wall (27-29) and with abnormalities seen in the attached mesentery. In this study, 10 of the 16 patients with

had CT findings

shows revealed

technology

these tients

emia that affected the bowel wall, attached mesentery, or both (Figs 3,4, 7). All patients in whom the attached

section

Surgery

findings of strangulation are associated with previously described CT

fluid of de-

at the root of the mesentery

loops of bowel, ble bowel.

a congenital obstructed and efferent

before

one

strangulation

evi-

diagon

the

of CT findings.

Most struction clinical

patients with small have characteristic presentations, and

bowel obhistories, plain radio-

graphic findings. In most of these patients, surgery is recommended and examination with CT is not indicated.

In patients suspected of having small bowel obstruction, we recommend the

early

abdominal

nonspecific

use

of CT whenever

radiographs

and,

are

in patients

plain normal

who

or

may

have complete small bowel obstruction, whenever conservative management or delay in surgery is contemplated. In patients in whom examination with CT is indicated, detection of CT signs

of closed-loop

result in close cal symptoms If

signs

present,

obstruction

should

monitoring and, if clinipersist, early surgery.

of strangulation

emergency

are

surgery

already

is recom-

mended. In conclusion, tions, CT appears

despite its limitato be a promising December

1992

with and may not lead to the development of strangulation. If only signs of closed-loop obstruction are detected at examination with CT, the existence and/or development of

14.

strangulation

16.

cannot

be predicted.

Acknowledgment:

The authors

guerite tion.

for manuscript

A. McKnight

thank

#{149} Mar-

15.

17.

prepara-

Figure

11.

adhesions in a woman

nal loops fluid. The the point the site of collapsed by mesentery. with viable

Closed-loop

obstruction

due

to

after hysterectomy was performed aged 65 years. The closed intesti(0) are distended and filled with loops of small intestine distal to of obstruction (i) are collapsed. At obstruction, there are two adjacent limbs of bowel (arrow) surrounded Surgery revealed volvulus bowel.

2.

3.

4.

imaging closed-loop

bowel

modality and

for diagnosis strangulating

obstruction.

enabled

In this study,

establishment

sis of mechanical

tion

of the intestinal

in all patients

tle signs

of small

CT

diagno-

displayed

loop,

sub7.

strangulation,

or both in most patients. We believe that these new observations and signs are relevant and important. The reliability

untested larger study,

findings

of these

and

signs,

must

prospective absence

however,

be evaluated

loop

tion (see Background)

in a

Volume

Number

#{149}

9.

did not rule

mesentery, or both was of bowel ischemia. Finally, loop may not be associated

185

8.

10.

or strangula-

out the diagnosis. However, detection of ischemic changes in the bowel wall, attached nostic closed

Rev Surg

is still

study. In our of characteristic CT

of closed

6.

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