OBJECTIVE: To evaluate the focused abdominal CT scan [FACT] in clinically equivocal cases of acute appendicitis in paediatric population.
METHODS: A cross-sectional study was conducted at the Radiology Department of Aga Khan Hospital, from August 2007 to November 2008. A total of 84 patients (42 males & 42 females) with clinically equivocal signs and symptoms of acute appendicitis referred to radiology department for CT evaluation were studied. CT findings were compared with histopathology and clinical follow-up.
RESULTS: The sensitivity of focused CT for acute appendicitis was 91%; specificity was 69% and accuracy of 76% while PPV and NPV were 58%, 94% respectively.
CONCLUSION: Focused unenhanced CT is a quick, accurate and non invasive modality for the assessment of clinically equivocal cases of acute appendicitis for ruling out patients and reducing negative appendectomies

Akhtar, Waseem

Ali, Farzana Nawaz

Ali, Sumera

Arshad, Muhammad

Nadeem, Naila

eCommons@AKU

eCommons@AKUDepartment of Radiology Medical College, PakistanMay 2011Focused abdominal CT scan for acute appendicitisin children: can it help in needWaseem AkhtarAga Khan UniversitySumera AliAga Khan UniversityMuhammad ArshadAga Khan UniversityFarzana Nawaz AliAga Khan UniversityNaila NadeemAga Khan UniversityFollow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_radiolPart of the Radiology CommonsRecommended CitationAkhtar, W., Ali, S., Arshad, M., Ali, F., Nadeem, N. (2011). Focused abdominal CT scan for acute appendicitis in children: can it helpin need. Journal of the Pakistan Medical Association, 61(5), 474-6.Available at: http://ecommons.aku.edu/pakistan_fhs_mc_radiol/24IntroductionAcute appendicitis is one of the commonest causesof acute abdomen in children needing surgical intervention.Historically, the diagnosis of appendicitis is primarily basedon clinical evaluation which can lead to a high rate ofnegative appendectomies1,2 due to non-specific signs andsymptoms particularly in children. Acute abdominal pain isa common complaint encountered in paediatrics and theprevalence of acute appendicitis amongst these patientsranges from 1 to 4% only.3,4 The clinical diagnosis of acuteappendicitis in children may be difficult as compared toadults due to their inability to communicate their symptoms.It can be further difficult as approximately one-third ofchildren present with non-specific clinical findings5 thatlead to high missing rate of missed acute appendicitis atinitial clinical examination in children.6 The introduction ofmodern techniques like ultrasound (U/S), computedtomography (CT) and magnetic resonance imaging (MRI)has proven helpful7-12 in the diagnosis of appendicitisespecially in clinically equivocal cases. Ultrasound is anideal imaging modality for initial assessment in patientssuspected with acute appendicitis.13 But it is operatordependent and at times unable to visualize through thebowel gases. Sonographic examination in children can alsobe difficult to perform due to extreme abdominal pain. Focused appendiceal computed tomography (FACT)is a modified form of pelvic CT9 examination taking thinsections, focusing on the right lower quadrant, withoutadministration of contrast media. It has shown furtherincreased in the diagnostic accuracy of CT scan forappendicitis and reduces the appendiceal perforation rates10leads to minimal hospital stay by reducing delay indiagnosis.14 Focused CT also has the advantage of reducedradiation exposure which is even more important inpaediatric population and has a lower cost compared toabdominal CT.15 FACT is a quick procedure and can alsoidentify other intra-abdominal etiologies of pain in patientswith acute abdomen.15FACT is relatively a new technique in our countryfor acute appendicitis and to best of our knowledge nostudy has been done to evaluate its role in paediatricpopulation in our part of the world. Therefore the objectiveof this study was to evaluate the focused abdominal CTscan in clinically equivocal cases of acute appendicitis inchildren.Patients and MethodsThe participants of the study were selected fromthe patients presenting to the Aga Khan UniversityHospital Karachi with acute abdomen and clinicalfindings suggestive of equivocal acute appendicitis fromAugust 2007 to November 2008 and referred to radiologydepartment for FACT examination. Equivocal acuteappendicitis criterion included atypical signs andsymptoms, and difficult clinical examination due toobesity, unco-operative patient or persistent pain in rightilliac fossa without signs of localized peritonism. MostVol. 61, No. 5, May 2011 474Original ArticleFocused abdominal CT scan for acute appendicitisin children: Can it help in need?Waseem Akhtar,1 Sumera Ali,2 Muhammad Arshad,3 Farzana Nawaz Ali,4 Naila Nadeem5Department of Radiology, Medical College,1,2,4 Pediatric Surgery,3,5 Aga Khan University Hospital, Karachi.AbstractObjective: To evaluate the focused abdominal CT scan [FACT] in clinically equivocal cases of acute appendicitisin paediatric population. Methods: A cross-sectional study was conducted at the Radiology Department of Aga Khan Hospital, fromAugust 2007 to November 2008. A total of 84 patients (42 males & 42 females) with clinically equivocal signs and symptoms of acute appendicitisreferred to radiology department for CT evaluation were studied. CT findings were compared with histopathologyand clinical follow-up.Results: The sensitivity of focused CT for acute appendicitis was 91%; specificity was 69% and accuracy of 76%while PPV and NPV were 58%, 94% respectively. Conclusion: Focused unenhanced CT is a quick, accurate and non invasive modality for the assessment ofclinically equivocal cases of acute appendicitis for ruling out patients and reducing negative appendectomies. Keywords: Acute appendicitis, CT, Focused, Radiography (JPMA 61:474; 2011).common presenting symptom was acute abdominal pain.Focused CT scan was done after taking written consentby parents. Purposive sampling was done to achieve theobjectives of the study. An inclusion criterion waspatients from 1-15 years of age with clinical suspicion ofappendicitis. They underwent focused CT abdomen andhad histopathologic results or clinical follow-up.Exclusion criteria were known cases of appendicitis,patients had whole abdomen CT or received oral/rectalcontrast. FACT was performed using a multi detector CTscanner (Toshiba aquiline). Scanning was performedfrom the L3 to pubic symphysis in all patients. Nooral/rectal or IV contrast was given. No bowelpreparation was advised. Collimation and imagereconstruction was done at 5mm. Coronal and sagittalreconstruction was also performed. Images werereviewed on reporting console as well as on hard copies.Interpretation of images for either positive or negativefindings for appendicitis was initially done by seniorradiology resident and final report was made byconsultant radiologist having experience of paediatricabdominal imaging. Appendicitis was diagnosed onCT,5,9,12,15,16 if the appendix did not fill completely withair and exceeded 6 mm in cross-sectional diameter or ifan appendicolith, adjacent fat stranding /extra luminalair, complex fluid collection, or mass was noted. The decision for operative intervention was made bythe paediatric surgeon on clinical, imaging and laboratoryfindings. The final diagnoses were established by surgicaland histologic evaluation of the appendix in patients whounderwent surgery or by clinical follow-up in patientstreated conservatively. Data was entered and analyzed inSPSS version 15. Sensitivity, specificity, accuracy, negativeand positive predictive values of FACT for acuteappendicitis was calculated. ResultsA total of 84 paediatric patients underwent focusedabdominal CT scan for acute appendicitis. Of whom 13(6%) patients were excluded due to non availability offollow-up or histopathologic findings. Finally our samplesize comprises of 71 patients (Mean age 11.8 ± 2.5 years,M: F 1:1). Minimum age of patient with suspectedappendicitis was 4 years while maximum age was 15 years.The prevalence of appendicitis on FACT was 51% (36/71)while over all prevalence in this study was 32% (23/71).There were 21(91%) true-positive diagnoses ofappendicitis. Fifteen false-positive (42%) diagnoses ofappendicitis were identified on FACT. There were 33 (69%)true-negative diagnoses for acute appendicitis. Two false-negative diagnoses (3%) of appendicitis were found inpatients with surgically proved appendicitis. Focusedabdominal CT had a sensitivity of 91%, specificity of 69%,and accuracy of 76% for the diagnosis of appendicitis.Negative and positive predictive values were 94% and 58%respectively. DiscussionThe results of this study clearly showed the utilityof focused CT scan abdomen in clinically equivocal casesof acute appendicitis in children and findings areconsistent with published studies.9,10,14,15 The sensitivityof CT for appendicitis in this study was 91% which iscomparable to published literature with pooled sensitivityof 94% in children.16,17 The specificity of CT scan in thisstudy was 69% which is lower than published pooledspecificity of diagnosing appendicitis in children of95%.16,17 The reason might be due to presence of normalincreased diameter appendix in our population as 6mm ormore appendicular diameter was taken as positive foracute appendicitis on CT.5,9,12,15,16 Another large multicenter study might be helpful for establishing theappendicular size criterion for appendicitis in ourpopulation. The other possibility of low specificity in thisstudy was over reading of images and high level ofsuspicion by radiologists. There were fifteen false positivecases and only two false negative cases, the cause of thesemight be due to difficulty in interpretations of CT imagesin thin patients with absence of natural fat contrast. Therewas only one incidental finding of haemorrhagic ovariancyst on CT scan in the absence of acute appendicitis, thisreflects the best clinical practice and use of CT scan onlyin selective equivocal children. The results of this studyshowed that in selective cases where clinical suspicion isin doubt FACT might be helpful in decision of surgicalintervention by excluding normal appendix or it mayestablish an alternative diagnosis. Ultrasound is another modality that can be used inclinically equivocal cases of acute appendicitis. Incomparison to CT, ultrasound has no risk of radiationexposure however, literature suggest a better accuracy ofCT in diagnosing acute appendicitis.5,9,12,15,16 FACT is afocused exam without contrast and with minimalpossible radiation exposure and its use can be justifiedby its higher diagnostic ability. Ultrasound sometimesmay not give good results because of excessive fat or airfilled bowels. CT is also better at visualizing thecomplications associated with appendicitis like presenceand extent of abscess and inflammation. Since our studyshowed a low specificity for FACT, we need a regionalcomparative study between US and CT to look at theirpre and post test probabilities to prove the superiority ofone over the other. This study has few limitations besides having single475 J Pak Med Assoccentre, selection of patients biased towards only inclusion ofpatients referred to radiology for CT examination.Radiologists were bound to diagnose whether appendicitiswas present or not, no room for intermediate diagnosis wasgiven. Degrees of experience among the radiologists inanalyzing CT for acute appendicitis were not taken intoaccount. Inter observer variability of CT interpretation wasnot assessed. No other investigation was used to support theCT diagnosis. Only one month follow-up of patients isavailable. No cost-effective analysis was performed in thispaper however CT fact reduces negative appendectomy rateand patient hospital stay that is indirectly reflective of costeffectiveness of CT fact.ConclusionFocused unenhanced CT has good sensitivity forruling out appendicitis in children and provides importantancillary information thus reducing negative appendectomyrate resulting in minimal hospital stay of patient and burdenof cost associated with surgical intervention. Since, FACT isa relatively new and underused modality to diagnoseappendicitis, radiologists are being over cautious, which isone of the reasons for the low specificity observed. Otherreasons may include a lack of customized criteria fordiagnosing appendicitis using FACT in our population. Based on the results of this study, in our settingFACT can be used to reduce the number of negativeappendectomy rates.References1. Kaiser S, Mesas-Burgos C, Soderman E, Frenckner B. Appendicitis inchildren--impact of US and CT on the negative appendectomy rate. Eur JPediatr Surg 2004; 14: 260-4.2. Khan JS, Hassan H, Khan JA. Investigations for Acute Appendicitis: Can werely on them? Pak J Surg 2002; 18: 27-30.3. Brewer BJ, Golden GT, Hitch DC, Rudolf LE, Wangensteen SL. Abdominalpain. An analysis of 1,000 consecutive cases in a University Hospitalemergency room. Am J Surg 1976; 131: 219-23.4. Scholer SJ, Pituch K, Orr DP, Dittus RS. Clinical outcomes of children withacute abdominal pain. Paediatrics 1996; 98: 680-5.5. Rao PM, Rhea JT, Rattner DW, Venus LG, Novelline RA. Introduction ofappendiceal CT: impact on negative appendectomy and appendicealperforation rates. Ann Surg 1999; 229: 344-9.6. Rothrock SG, Pagane J. Acute appendicitis in children: emergency departmentdiagnosis and management. Ann Emerg Med 2000; 36: 39-51.7. Franke C, Bohner H, Yang Q, Ohmann C, Roher HD. Ultrasonography fordiagnosis of acute appendicitis: results of a prospective multicenter trial.AcuteAbdominal Pain Study Group. World J Surg 1999; 23: 141-6.8. Hormann M, Paya K, Eibenberger K, Dorffner R, Lang S, Kreuzer S, et al.MR imaging in children with nonperforated acute appendicitis: value ofunenhanced MR imaging in sonographically selected cases. AJR Am JRoentgenol 1998; 171: 467-70.9. Rao PM, Rhea JT, Novelline RA, McCabe CJ, Lawrason JN, Berger DL, et al.Helical CT technique for the diagnosis of appendicitis: prospective evaluationof a focused appendix CT examination. Radiology 1997; 202: 139-44.10. Sivit CJ, Siegel MJ, Applegate KE, Newman KD. When appendicitis issuspected in children. Radiographics 2001; 21: 247-62.11. Teo EL, Tan KP, Lam SL, Ong CL, Wong CS. Ultrasonography and computedtomography in a clinical algorithm for the evaluation of suspected acuteappendicitis in children. Singapore Med J 2000; 41: 387-92.12. Wise SW, Labuski MR, Kasales CJ, Blebea JS, Meilstrup JW, Holley GP, etal. Comparative assessment of CT and sonographic techniques forappendiceal imaging. AJR Am J Roentgenol 2001; 176: 933-41.13. Sohail S, Siddiqui KJ. Doptaus -- A simple criterion for improvingSonographic Diagnosis of acute appendicitis. J Pak Med Assoc 2009;59: 75-9.14. Todd J, Armon C, Griggs A, Poole S, Berman S. Increased rates of morbidity,mortality, and charges for hospitalized children with public or no healthinsurance as compared with children with private insurance in Colorado andthe United States. Paediatrics 2006; 118: 577-85.15. Rhea JT, Rao PM, Novelline RA, McCabe CJ. A focused appendiceal CTtechnique to reduce the cost of caring for patients with clinically suspectedappendicitis. AJR Am J Roentgenol 1997; 169: 113-8.16. Saleem OA, Khasawneh M. Role of CT scan in diagnosis of acuteappendicitis. Rawal Med J 2007; 32: 39-40.17. Doria AS, Moineddin R, Kellenberger CJ, Epelman M, Beyene J, Schuh S, etal. US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta-Analysis. Radiology 2006; 241: 83-94.Vol. 61, No. 5, May 2011 476

Focused abdominal CT scan for acute appendicitis in children: can it help in need

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Focused abdominal CT scan for acute appendicitis in children: can it help in need

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