Ultrasonographic diagnosis of acute appendicitis

Original papers Medical Ultrasonography 2009, Vol. 11, no. 3, 7–18 Ultrasonographic diagnosis of acute appendicitis Călin Moş1, Teodor Ile2, Monica ...
Author: Bertha Lewis
52 downloads 1 Views 2MB Size
Original papers

Medical Ultrasonography 2009, Vol. 11, no. 3, 7–18

Ultrasonographic diagnosis of acute appendicitis Călin Moş1, Teodor Ile2, Monica Hălbac2, Laura Chiş2, Sorin Vesa2, Ştefan Andor2 1 2

University of Oradea, Faculty of Medicine and Pharmacy, Romania County Hospital, Beiuş, Romania

Abstract Introduction. Appendectomy, the most frequent surgical intervention, has 20-30% rate of negative appendectomy mostly because of 30-45% cases with unspecific clinical examination. The objective of this study was to determine the contribution of ultrasonography in acute appendicitis (AA) diagnosis in patients with abdominal pain in the right lower quadrant. Material and method. A number of 262 patients with clinical suspicion of AA were investigated. The positive diagnosis criteria were considered to be the appendix external diameter >6 mm, appendix wall thickness >3 mm, partial or total absence of wall stratification, coprolites or/and liquid in excess in the appendix lumen, hypervascularization of appendix wall, echogenicity enhanced and hyperemia in periappendicular mesenteric fat, periappendicular collection (abscess) or peritoneal collection (peritonitis). Results. Appendix was identified by ultrasonography in 199 out of 262 of patients (75.9%). Normal appendix was less visualized (in 61.9%) comparing to pathologic appendix (91.3%). Ultrasonography demonstrated an 89.4% sensibility, 95.2% specificity, positive predictable value 95.5% and negative predictable value 88.9% in the detection of AA. Preoperative ultrasonographic examination in patients with abdominal pain of the right lower quadrant leads to 9.9% negative rate of appendectomies. Conclusions. In cases of abdominal pain located in the right lower quadrant, ultrasonography is a quick non-invasive and low cost method which can contribute to an early positive diagnosis and also a decrease in the number of unnecessary appendectomies. Key-words: acute appendicitis, ultrasound, diagnosis

Rezumat Introducere. Apendicectomia, cea mai frecventă intervenţie chirurgicală, are o rată de 20-30% de apendicectomii negative, in primul rind deoarece in aproximativ 30-45% cazuri examenul clinic este nespecific. Scopul studiului este de a determina contribuţia ecografiei în diagnosticul apendicitei acute la cazurile cu sindrom dureros de fosă iliacă dreaptă. Material şi metodă. S-au evaluat ecografic 262 de pacienţi cu suspiciunea clinică de apendicită acută. Criteriile ecografice de diagnostic pozitiv au fost: diametrul extern al apendicelui peste 6 mm, grosimea a peretelui peste 3 mm, dispariţia parcelară sau totală a stratificării pereţilor, prezenţa în lumen a coproliţilor şi/sau a lichidului în exces, hipervascularizaţia peretelui apendicular, creşterea ecogenităţii şi hiperemia grăsimii mezenterice periapendiculare, prezenţa unei colecţii periapendiculare (abces) sau peritoneale (peritonită). Rezultate. Apendicele a fost identificat ecografic la 199 dintre cei 262 de pacienţi (75,9%). Apendicele normal a fost mai rar vizualizat (61,9%) comparativ cu cel patologic (91,3%). Ecografia are sensibilitate de 89,4%, specificitate de 95,2%, acurateţe de 94,3%, valoare predictivă pozitivă de 95,5% şi valoare predictivă negativă de 88,9% în detectarea apendicitei acute. Examinarea ecografică preoperatorie a pacienţilor cu suspiciunea clinică de apendicită acută a dus la o rata de apendicectomii negative de doar 9,9%. Concluzii. În cazul unei simptomatologii dureroase de fosă iliacă dreaptă, ecografia este o metodă neinvazivă, rapidă şi cu preţ de cost scăzut care poate să contribuie la un diagnostic pozitiv precoce, la diminuarea ratei de apendicectomii cu apendice normal şi la clarificarea diagnosticului diferenţial. Cuvinte cheie: apendicită acută, ecografie, diagnostic

Address for correspondence: Dr. Călin Moş Str. Andrei Şaguna nr.1 415200, Beiuş, jud. Bihor, România e-mail: [email protected]

Acute appendicitis (AA) is the most common acute surgical condition [1], about 7% of the population having an appendectomy during their lifetime [2]. Maximum incidence is between 6 and 30 years [3,4]. In about 30-45% of cases the clinical evaluation is unspecific [5].

2

Călin Moş et al

The appendix is a worm-shaped pouch originating from the lowest part of cecum. It usually has an intraperitoneal position (anterior or retrocecal) in contact with the anterior parietal peritoneum. A wide mesentary permits the appendix rotation in several positions. So in 30% of cases the appendix is placed in the pelvis, retrocecal or retroperitoneal. These positions can modify clinical signs and symptoms of AA [6]. AA are caused by obstruction of the appendix lumen through several causes: lymph hyperplasia (especially in children and young adults in viral infections, mononucleosis, gastroenteritis or ileocolitis), coprolites, parasites, foreign body, Crohn’s disease or neoplasm [5,7,8,9]. If the diagnosis of AA is based only on clinical and laboratory findings, about 20-30% of appendectomies are not confirmed at pathologic examination [9,10,11]. In AA an early diagnosis is crucial to reduce the risk of complications (perforation, occlusion, sepsis) which can increase the mortality especially at extreme ages [1]. In a small number of patients with AA (between 1-10%) the appendix inflammation is discrete, clinical signs are blurred and rapidly subsided, and the clinical evolution is rapidly to spontaneous remission. These are called abortive appendicitis, limited appendicitis or spontaneous healing appendicitis [12,13]. In atypical cases of AA, the surgeon have to choose between instant and delayed surgery. The ultrasonography (US) of abdomen and appendix region can help the surgeon to take the proper decision. The advantages of US in AA diagnosis are the low cost, the lack of irradiation, and the possibility to examine carefully and repetitively the maximum sensibility zone. The main disadvantage of the US is the operatordependence and the difficulty in scanning obese patients. [14,15,16]. An experienced operator, with the aid of a modern devices (with high resolution probe), could have a sensitivity, accuracy and specificity around 90% in US diagnostic of AA. Also, in the patients with appendicitislike symptoms, US can reveal the correct diagnosis in almost 70-80% of cases [17]. The aim of our study was to evaluate the contribution of the US for the positive and differential diagnosis of the AA, in patients with abdominal pain localized in the right lower quadrant. Material and method The study comprised 262 patients (136 males, 126 females, aged between 4–73) presenting with right lower quadrant abdominal pain at the Beius County Hospital between December 2007 and July 2009. They all had clinical suspicion of AA. US was performed by a doc-

Ultrasonographic diagnosis of acute appendicitis

tor (CM) with experience in gastrointestinal tract US. A Voluson 730 PRO General Electric Kretz Technik ultrasound machine with multifrequence probe (1.5-18.5 MHz) was used. The examination protocol, based on graded compression describe by Puylaert [18] included: 1. Convex probe use. The US examination started with an abdominal general scanning (to exclude an extraappendicular pathology) using a 1.5-4.5 MHz or 4.08.5 MHz convex probe, depending on body weight. For obese patients the same convex probe was used for appendix region examination. 2. Linear probe use. For the examination of the appendix region we used a 5-18.5 MHz linear probe. According to the Puylaert technique [18,19] a graded compression was exerted with the transducer, to dislocate the air and to identify the most painful region. The landmarks of the region (cecum, last portion of the ileum, iliopsoas muscle, iliac vessels and appendix) were identified. The examination began with sections from the ascending colon to the cecum. After the identification of the cecum base, longitudinal sections from the lateral to the median part of the cecum were made. Usually the appendix was identified in the maximum painful zone. If the appendix was not identified in its normal position, the examination continued to explore the retrocecal, retrocolic, pelvic and retroileal regions using the appendix base as a landmark (always the base was situated in the same position). We used US in gray scale for morphological analysis and Doppler US for the examination of appendix vascularization (with a small velocity scale and 70-120 Hz parietal filter). US exclusion criteria for AA were an US unidentifiable appendix or a compressible appendix, oval shape in transverse section, with external diameter under 6 mm, wall thickness under 3 mm, wall layers and normal periappendicular mesenteric fat. US positive diagnosis criteria for AA were considered the external diameter of the appendix over 6 mm, the appendix wall thickness over 3 mm, total or partial wall layers nonvisualisation, coprolites and/or fluid excess into appendix lumen, hypervascularization of the appendix wall, enhance of echogenicity and hyperemia of the periappendicular mesenteric fat, periappendicular collection (abscess) or peritoneal collection (peritonitis). The histopathological examination of the appendix was performed in all surgical cases. The result was considered true positive when the US diagnosis concurred with the histopathological findings and true negative when the histopathology for AA was negative or there was no relapse in 2 weeks of follow up of the nonsurgical patients.

Medical Ultrasonography 2009; 11(3): 7–18

The result was considered false positive when there was a US diagnosis of AA with normal histopathological findings in the appendix, and false negative when US found a normal or unidentifiable appendix with positive histopathology for AA. A 2x2 table and χ2 test were used for the evaluation of the results. The sensitivity, specificity, accuracy, positive and negative predictive values were determinate (PPV, NPV). The confidence interval was 95%. Results In the majority of the cases the appendix was identi-

fied in about 1-3 minutes. An unidentified US appendix was considered a normal appendix. From 262 examined patients, 141 were submitted to appendicectomy. In 127 patients there was a histological confirmation of AA. In 14 patients the histological examination was negative resulting 9.9% appendicectomies for a normal appendix (tab I, tab II). The clinical situations which led to false positive and false negative results are presented in table III. The statistical data analysis shows 89% sensibility, 95.2% specificity, 94.3% accuracy, 95.5% PPV and 88.9% NPV of the US in diagnosis of AA.

Table I. US identification of the appendix and the therapy of the patients with pain in the right lower quadrant (RLQ); AA – acute appendicitis US findings

Number of patients with pain Patients with appendectomy Patients with conservative therapy US diagnosis of AA RLQ (total 262) (total 141) (total 120) (total 118)

Identified appendix

199 (75,9%)

120 (89,4%)

79 (65,8%)

103 (87,3%)

Unidentified appendix

63 (24.1%)

21 (10,6%)

41 (34,2%)

15 (12,7%)

Table II. US diagnosis and the therapy of the patients with pain in the right lower quadrant (RLQ); AA- acute appendicitis US diagnosis

Number of patients with pain Patients with appendectomy Patients with conservative therapy US diagnosis of AA in RLQ (total 262) (total 141) (total 120) (total 118)

AA

127 (48,5%)

127 (90,1%)

0 (0%)

112 (94,9%)

Without AA

135 (51,5%)

14 (9,9%)

120 (100%)

6 (5,1%)

Table III. The causes of false positive or false negative results at US Outcome type

False positive

The cause of false outcome

Number of cases

• hydrosalpings • mucocele with pseudomyxoma peritonei in small quantity • terminal ileum segmental necrosis • Meckel’s diverticulitis • cecal diverticulitis • ovarian torsion Total

False negative

Appendix lack of identification without real associated pathology • obesity • appendix point position • difficulties in practicing graded compression • pain absence at compression in right lower quadrant Appendix lack of identification with associated pathology • cecum neoplasm • infectious ileitis • hyperplastic cholecystosis with subhepatic abscess produced by appendix perforation • perforated appendix for an appendix and cecum located in left lower quadrant Total

1 1 1 1 1 1 6 5 2 3 1 1 1 1 1 15

3

4

Călin Moş et al

Discussions

Ultrasonographic diagnosis of acute appendicitis

The detection by US of the normal appendix vary in published papers between 0% and 95% [18,20,21,22,23, 24,25,26], depending mostly on the US machines’ performances. For example, Puylaert in 1986 (in a study describing the graded compression technique for appendix examination) mentions the lack of normal appendix visualization [18]. In a recent paper in 2005 [26] the detection rate of the normal appendix increased to 82%. The main examination technique is one of the graded compression [18]. Some authors consider that anterior graded compression combined with posterior compression can increase significantly the rate of appendix detection [24]. The appendix examination must be performed in its entire length because there are situations with focal inflammation, especially on the tip of appendix. The incomplete examination of the appendix can generate false results [27].

On longitudinal scan, the normal appendix is a compressible tubular blind-ending structure, without peristaltic movements, no mucosal stripes and usually without visible hypervascularization. External maximum diameter is considered to be 4.7±1.2 mm [28] but in exceptional cases can increase up to 8-11 mm [28]. Most of the authors considered a diameter of 6 mm as the superior value for a normal appendix (fig 1, fig 2) [29,30]. Normal appendix lumen can occasionally be filled with noninflammatory content (faecals, mucus) achieving an uncompressible appendix and an external diameter over 6 mm (up to 10-11 mm) [30,31,32]. For this reason there are authors who consider that the parietal thickness (the distance from the hyperechoic serosa to the hyperechoic lumen, normal10 mm (fig 11, fig 12, fig 13). Sometimes, there is no significant pain during examination (due to decreased pressure following appendix rupture) [47, 52]. The most specific feature is the presence of the pericecal abscess, with impure fluid content and small echoes inside and mass effect on the nearby intestinal ansae [52]. In small perforations, an emergency appendicectomy is necessary. In cases with periappendicular phlegmons, an initial conservative therapy followed by postponed appendicectomy is preferred. For well defined abscesses a US guided drainage can be performed before appendicectomy [52, 53, 54, 55, 56, 57].

In abortive appendicitis (7-10% of cases) the appendix usually does not contains coprolites, no periappendicular abscess or inflammatory signs are detected, and the average the appendix diameter is 8.5 mm [12, 13]. Recurrence rate after an abortive appendicitis is 38% after 3 months and 70% after 1 year. The recurrence is significantly enhanced if the appendix diameter is >8 mm under compression [13]. The position of the appendix can influence its detection. A retrocecal appendix is better visualized from coronal sections (with the probe direction from lateral to medial). A pelvic appendix can be detecting by using an endovaginal probe. An unidentified appendix is suggestive but not revealing for a normal appendix In the differential diagnosis of AA, miscellaneous abdominal and extrabdominal pathology should be taken into account (tab IV). In the last years, new techniques for the improvement of the US images have been used. In a recent study [58] the use of Spatial Compounding Imaging (cross beam) and Tissue Harmonic Imaging increased the rate of detection of the appendix by 19%. The examiner’s experience in appendix US is very important. During this study the improvement in examiner’s abilities, especially for normal appendix identification, were recorded. The normal appendicular vessels are of small calibres with slow blood velocities. The normal appendix does not usually present distinguishable vascularization at Doppler US. In AA the vascular diameters and blood velocities are increased, being easy to detect in Doppler US (fig 14, fig 15, fig 16) [59, 60]

Table IV. Differential diagnosis of the acute appendicitis Differential diagnosis Obstetrical and gynaecologic diseases

Pelvic inflammatory disease, ovarian cyst rupture, tubular pregnancy, tubular pathology, endometriosis

Gastrointestinal diseases

Ulcer, diverticulitis, Chron’s disease, infectious enteritis, ileocecitis, ileitis, tuberculosis, intestinal occlusion, intestinal infarction, invagination, volvulus, tumors, acute pancreatitis, mesenteric adenitis, mesenteric infarction

Urinary diseases

Renal colic, renal abscess, pyelonephritis, prostatitis testicular torsion

Liver and gallbladder diseases

Hepatic abscess, acute cholecystitis

Muscle diseases

Iliopsoas muscle abscess or haematoma, rectus abdominis muscle sheath haematoma

Epiploon diseases

Infarction, torsion, appendagitis

Pulmonary diseases

Pneumonia, pulmonary infarction

Parasitic infections

Ascaridiosis

7

8

Călin Moş et al

Fig 14. AA: hypervascularization on color Doppler.

Ultrasonographic diagnosis of acute appendicitis

Fig 17. AA vascularization: arterial and venous signal (triplex mode).

In evolution, the vascular signal could become difficult to detect (or only the arterial signal is detected) due to parietal necrosis. The extension of the parietal necrosis in the gangrenous AA leads to the absence of appendix vascularization with periappendicular fat hyperemia (fig 18) [59, 64, 65].

Fig 15. AA: hypervascularization on power Doppler.

Fig 18. AA with discrete appendicular vascularization due of parietal necrosis and periappendicular hyperemia.

Fig 16. AA with high appendicular and periappendicular hypervascularization.

Some authors consider that inflammatory activity is proportional to the quantity of color signal found in the appendix wall [61,62]. The hypervascularization is present from the onset of AA. Both arterial and venous vascular signals could be detected. (fig17) [63].

In abortive appendicitis, at the onset a parietal hypervascularization can be recorded (fig 19), hypervascularization reversible in evolution [59, 62]. The appendix could be hypervascularizated also in ileocecal inflammatory diseases [66] or if the appendix orifice is obstructed by a cecal tumour [67]. A recent study suggests that Power Doppler in combination with contrast agents is the most sensitive method for AA diagnosis (sensitivity 100%) [68]. The role of the 3D/4D US for appendix evaluation has not been evaluated yet. This study does not concern

Medical Ultrasonography 2009; 11(3): 7–18

Fig 19. Abortive appendicitis with parietal hypervascularization. After 24 hours the patient had a quickly spontaneous favourable course and appendectomy was not necessary.

itself with this evaluation but we do confirm that in some cases the 3D reconstruction did improve the US description of the lesions (fig 20, fig 21, fig 22, fig 23 fig 24).

Fig 20. Appendicular and perriappendicular findings in AA evaluated in 3 orthogonal projections

Fig 21. Small periappendicular collection due to appendix perforation. The site of perforation and the extension of collection are better visible on C plane.

Fig 22. Periappendicular abscess view with tomographic ultrasound imaging technique – serial tomographic sections

Fig 23. Tridimensional reconstruction of a periappendicular abscess

Fig 24. Tridimensional reconstruction of the vascularization of inflamed appendix

9

10

Călin Moş et al

Our statistical analysis results are in concordance with those from the literature. The majority of studies showed a sensibility between 64-96%, specificity between 88-99%, accuracy between 82-97%, PPV between 79-99% and NPV between 75-97% of the US in AA diagnosis [18, 25, 40, 60, 69, 70, 71, 72]. Our study confirms that nowadays, with modern devices and an experienced operator, it is possible to achieve the most accurate results. The sensibility of the method was lower than the specificity because of the uncontrolled factors responsible for the majority of the false negative results (obesity, unspecific localization of appendix and associated diseases). It must be mentioned that the US in our study was performed only after clinical examination and laboratory tests. The use of the US as a diagnostic method, together with clinical examination and laboratory tests decreased significantly the rate of unnecessary appendicectomies from 20-30% [9, 10, 11, 70] to 9.9%. Conclusion Ultrasonography is a sensitive and specific method for AA diagnosis. In patients with right lower quadrant abdominal pain the US can identify the source of the painappendicular or non-appendicular. US has an important role in the AA management and also implications in the therapeutic decision. US examination could considerably decrease the number of unnecessary appendicectomies. Acknowledgments Special thanks to Mr. Sebastien Eckert, chairman of Medisys Societe, Paris, France for his priceless help.

References 1. Liu CD, McFadden DW. Acute abdomen and appendix. In: Greenfield LJ, et al., eds. Surgery: scientific principles and practice. 2d ed. Philadelphia: Lippincott-Raven, 1997: 1246-1261. 2. Addiss DG, Shaffer N, Fowler BS, Tauxe RV. The epidemiology of appendicitis and appendectomy in the United States. Am J Epidemiol 1990; 132: 910-925. 3. Schwartz SI. Appendix. In: Schwartz SI, ed. Principles of surgery. 6th ed. New York: McGraw Hill, 1994: 13071318. 4. Puig S, Hormann M, Rebhandl W, Felder-Puig RF, Prokop M, Paya K. US as a primary diagnostic tool in relation to negative appendectomy: six years experience. Radiology 2003; 226: 101–104.

Ultrasonographic diagnosis of acute appendicitis 5. Telford GL, Condon RE. Apendix. In: Zuidema GD, Surgery of the alimentary tract. 3rd ed. Philadelphia: Saunders, 1991: 133-141. 6. Hardin DM Jr. Acute appendicitis: review and update. Am Fam Physician 1999; 60: 2027-2034. 7. Wilcox RT, Traverso LW. Have the evaluation and treatment of acute appendicitis changed with new technology? Surg Clin North Am 1997; 77: 1355-1370. 8. Graffeo CS, Counselman FL. Appendicitis. Emerg Med Clin North Am 1996; 14: 653-671. 9. Deal DR. Acute appendicitis. In: Sleisonger MH, Fordtran JS, eds. Gastrointestinai disease. Pathophysiology, diagnosis, management. Philadelphia:Saunders, 1973: 14941500. 10. Lewis FR, Holcroft JW, Boey J, Dunphy E. Appendicitis. A critical review of diagnosis and treatment in 1,000 cases. Arch Surg 1975; 110: 677-684. 11. Rao PM, Rhea JT, Novelline RA, Mostafavi AA, McCabe CJ. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med 1998; 338: 141-146. 12. Migraine S, Atri M, Bret PM, Lough J0, Hinchey JE. Spontaneously resolving acute appendicitis:clinical and sonographic documentation. Radiology 1997; 205: 55-58. 13. Cobben LP, de Van Otterloo AM, Puylaert JB. Spontaneously resolving appendicitis: frequency and natural history in 60 patients. Radiology 2000; 215: 349–352. 14. Rao PM, Feltmate CM, Rhea JT, Schulick AH, Novelline RA. Helical computed tomography in differentiating appendicitis and acute gynecologic conditions. Obstet Gynecol 1999; 93: 417-421. 15. Rao PM, Rhea JT, Novelline RA, et al. Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination. Radiology 1997; 202: 139-144. 16. Orr RK, Porter D, Hartman D. Ultrasonography to evaluate adults for appendicitis: decision making based on metaanalysis and probabilistic reasoning. Acad Emerg Med 1995; 2: 644-650. 17. Gaensler EH, Jeffrey RB Jr, Laing FC, Townsend RR. Sonography in patients with suspected acute appendicitis: value in establishing alternative diagnoses. AJR Am J Roentgenol 1989; 152: 49-51. 18. Puylaert JB. Acute appendicitis: US evaluation using graded compression. Radiology 1986; 158: 355-360. 19. Puylaert JB, Lalisang RI, van der Werf SD, Doornbos L. Campylobacter ileocolitis mimicking acute appendicitis: differentiation with graded-compression US. Radiology 1988; 166: 737–740. 20. Puylaert JB, Rutgers PH, Lalisang RI, et al. A prospective study of ultrasonography in the diagnosis of appendicitis. N Engl J Med 1987; 317: 666–669. 21. Garcia Pena BM, Mandl KD, Kraus SJ, et al. Ultrasonography and limited computed tomography in the diagnosis and management of appendicitis in children. JAMA 1999; 282: 1041–1046. 22. Schulte B, Beyer D, Kaiser C, Horsch S, Wiater A. Ultra-

Medical Ultrasonography 2009; 11(3): 7–18

23.

24.

25. 26.

27.

28.

29.

30.

31. 32.

33.

34.

35.

36.

37.

38.

39.

sonography in suspected acute appendicitis in childhood: report of 1285 cases. Eur J Ultrasound 1998; 8: 177–182. Baldisserotto M, Marchiori E. Accuracy of noncompressive sonography of children with appendicitis according to the potential positions of the appendix. AJR Am J Roentgenol 2000; 175: 1387–1392. Lee JH, Jeong YK, Hwang JC, Ham SY, Yang SO. Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis. AJR Am J Roentgenol 2002; 178: 863-868. Rioux M. Sonographic detection of the normal and abnormal appendix. AJR Am J Roentgenol 1992; 158: 773–778 Vriesman AB, Puylaert J. Appendix: mimics of appendicitis. Alternative nonsurgical diagnoses at sonography and CT. The Radiology Assistant, 2005. Lim HK, Lee WJ, Lee SJ, Namgung S, Lim JH. Focal appendicitis confined to the tip: diagnosis at US. Radiology 1996; 200: 799–801. Yabunaka K, Katsuda T, Sanada S, Fukutomi T. Sonographic appearance of the normal appendix in adults. J Ultrasound Med 2007; 26: 37-43. Jeffrey RB Jr, Laing FC, Lewis FR. Acute appendicitis: high-resolution real time US findings. Radiology 1987; 163: 11-14. Jeffrey RB Jr, Laing FC, Townsend RR. Acute appendicitis: sonographic criteria based on 250 cases. Radiology 1988; 167: 327–329. Simonovsky V. Sonographic detection of normal and abnormal appendix. Clin Radiol 1999; 54: 533–539. Park NH, Park CS, Lee EJ, et al. Ultrasonographic findings identifying the faecal-impacted appendix: differential findings with acute appendicitis. Br J Radiol 2007; 80: 872-877. Hahn HB, Hoepner FU, Kalle T, et al. Sonography of acute appendicitis in children: 7 years experience. Pediatr Radiol 1998; 28: 147–151. Simonovsky V. Normal appendix: is there any significant difference in the maximal mural thickness at us between pediatric and adult populations? Radiology 2002; 224: 333–337. Rettenbacher T, Hollerweger A, Macheiner P, et al. Presence or absence of gas in the appendix: additional criteria to rule out or confirm acute appendicitis-evaluation with US. Radiology 2000; 214: 183-187. Yabunaka K, Katsuda T, Sanada S, Fukutomi T. Sonographic appearance of the normal appendix in adults. J Ultrasound Med 2007; 26: 37-43. Rettenbacher T, Hollerweger A, Macheiner P, et al. Ovoid shape of the vermiform appendix: a criterion to exclude acute appendicitis – evaluation with US. Radiology 2003; 226: 95-100. Fakhry JR, Berk RN. The “target” pattern: characteristic sonographic feature of stomach and bowel abnormalities. AJR Am J Roentgenol 1981; 137: 969-972. Wiersma F, Sramek A, Holscher HC. US features of the normal appendix and surrounding area in children. Radiology 2005; 235: 1018-1022.

40. Abu-Yousef MM, Bleicher JJ, Maher JW, Urdaneta LF, Franken EA Jr, Metcalf AM. High-resolution sonography of acute appendicitis. AJR Am J Roentgenol 1987; 149: 5358. 41. Deutsch A, Leopold GR. Ultrasonic demonstration of the inflamed appendix. Radiology 1981; 140: 163-164. 42. Himeno S, Yasuda S, Oida Y, et al. Ultrasonography for the diagnosis of acute appendicitis. Tokai J Exp Clin Med 2003; 28: 39-44. 43. Lee JH, Jeong YK, Park KB, Park JK, Jeong AK, Hwang JC. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. AJR Am J Roentgenol 2005; 184: 91–97. 44. Takada T, Yasuda H, Uchiyama K, Hasegawa H, Shikata J. Ultrasonographic diagnosis of acute appendicitis in surgical indication. Int Surg 1986; 71 :9-13. 45. Jeffrey RB Jr, Laing FC, Lewis FR. Acute appendicitis: high-resolution real-time US findings. Radiology 1987; 163: 11-14. 46. Sivit CJ, Siegel MJ, Applegate KE, Newman KD. When appendicitis is suspected in children. Radiographics 2001; 21: 247–262. 47. Borushok KF, Jeffrey RB Jr, Laing FC, Townsend RR. Sonographic diagnosis of perforation in patients with acute appendicitis. AJR Am J Roentgenol 1990; 154: 275-278. 48. Nitecki S, Karmeli R, Sarr MG.. Appendiceal calculi and fecaliths as indications for appendectomy. Surg Gynecol Obstet 1990; 171: 185–188. 49. Jones BA, Demetriades D, Segal I, Burkitt DP. The prevalence of appendiceal fecaliths in patients with and without appendicitis: a comparative study from Canada and South Africa. Ann Surg 1985; 202: 80–82. 50. Shaw RE. Appendix calculi and acute appendicitis. Br J Surg 1965; 52: 451–459. 51. Noguchi T, Yoshimitsu K, Yoshida M. Periappendiceal hyperechoic structure on sonography: a sign of severe appendicitis. J Ultrasound Med 2005; 24: 323–327. 52. Skoubo-Kristensen E, Hvid I. The appendiceal mass: conservative management. Ann Surg 1982; 196: 584-587. 53. Hoffmann J, Lindhard A, Jensen HE. Appendix mass: conservative management without interval appendectomy. Am J Surg 1984; 148: 379-382. 54. Bagi P, Dueholm S. Nonoperative management of the ultrasonically evaluated appendiceal mass. Surgery 1987: 101: 602-605. 55. Paull DL, Bloom GP. Appendiceal abscess. Arch Surg 1982; 117: 1017-1019. 56. Jeffrey RB Jr, Tolentino CS, Federle MP, Laing FC. Percutaneous drainage of periappendiceal abscesses: review of 20 patients. AJR Am J Roentgenol 1987; 149: 59-62. 57. Jeffrey RB Jr, Federle MP, Tolentino CS. Periappendiceal inflammatory masses: CT-directed management and clinical outcome in 70 patients. Radiology 1988; 167: 13-16. 58. Scott T, Swan H, Jurriaans E, Voss M. Sonographic detection of the normal appendix does the combination of realtime spatial compounding and tissue harmonic imaging make a difference? JDMS 2004; 20: 326-334.

11

12

Călin Moş et al 59. Quillin SP, Siegel MJ. Appendicitis in children: color Doppler sonography. Radiology 1992; 184: 745-747. 60. Kessler N, Cyteval C, Gallix B, et al. Appendicitis: evaluation of sensiticity, specificity and predictive values of US, Doppler US and laboratory findings. Radiology 2004; 230: 472-478. 61. Lim HK, Lee WJ, Kim TH, Namgung S, Lee SJ, Lim JH. Appendicitis: usefulness of color Doppler US. Radiology 1996; 201: 221–225. 62. Quillin SP, Siegel MJ. Appendicitis: efficacy of color Doppler sonography. Radiology 1994; 191: 557–560. 63. Patriquin HB, Garcier JM, Lafortune M, et al. Apendicitis in children and young adults: Doppler sonographic-pathologic correlation. AJR Am J Roentgenol 1996; 166: 629-633. 64. Quillin SP, Siegel MJ. Diagnosis of appendiceal abscess in children with acute appendicitis: value of color Doppler sonography. AJR Am J Roentgenol 1995; 164: 1251-1254. 65. Hernanz-Schulman M. Applications of Doppler sonography to diagnosis of extracranial pediatric disease. Radiology 1993; 189: 1-14. 66. Ripollés T, Martínez MJ, Morote V, Errando J. Appendiceal involvement in Crohn’s disease: gray-scale sonography and color Doppler flow features. AJR Am J Roentgenol

Ultrasonographic diagnosis of acute appendicitis 2006; 186: 1071–1078. 67. Hermans JJ, Hermans AL, Risseeuw GA, Verhaar JC, Meradji M. Appendicitis caused by carcinoid tumor. Radiology 1993; 188: 71-72. 68. Incesu L, Yazicioglu AK, Selcuk MB, Ozen N. Contrastenhanced power Doppler US in the diagnosis of acute appendicitis. Eur J Radiol 2004; 50: 201–209. 69. Hale DA, Molloy M, Pearl RH, Schutt DC, Jaques DP. Appendectomy: a contemporary appraisal. Ann Surg 1997; 225: 252–261. 70. Riyad MN, Ouzounov GK, Wafaie IK, Gamal MA, Grover VK. Evaluation of sonography in the diagnosis of suspected acute apendicis. Kuwait Med J 2003; 33: 148-152. 71. Keyzer C, Zalcman M, De Maertelaer V, et al. Comparison of US and unenhanced multi-detector row CT in patients suspected of having acute appendicitis. Radiology 2005; 236: 527–534. 72. Doria AS, Moineddin R, Kellenberger CJ, et al. US or CT for diagnosis of appendicitis in children and adults? A metaanalysis? Radiology 2006; 241: 83-94. 73. Ooms HW, Koumans RK, Ho Kang You PJ, Puylaert JB. Ultrasonography in the diagnosis of acute appendicitis. Br J Surg 1991; 78: 315–318

Suggest Documents