Sensitivity and specificity of focused CT for the diagnosis of acute appendicitis


  • Theerarat Manmanee Krabi Hospital


Acute appendicitis, Computed tomography, Focused CT


Background: Contrast-enhanced CT abdomen and pelvis plays the key role in the workup of acute appendicitis. With increasing rates of CT scans, concerns about the risks from radiation exposure are also increased. Focused CT is one of alternative protocols that has been suggested considering to radiation dosage. Therefore, accuracy of focused CT for the diagnosis of acute appendicitis was studied.

Objective: To determine accuracy of focused CT for the diagnosis of acute appendicitis

Method: Retrospective review of 270 patients with CT scans for evaluation of suspected appendicitis in Krabi hospital from April 2023 to September 2023 were included in this study. From those CTs, we reconstructed images with limited scan range from superior border of L3 to superior border of pubic symphysis which served as the focused CT. These focused CTs were reviewed, assessing for appendix visualization and diagnosis of acute appendicitis or other diseases. The reference standard was obtained from medical records, intra-operative findings, and/or histopathology.

Results: The appendix was completely covered by focused CT in 269 cases and partially covered in 1 case. 94 cases (34.81%) showed acute appendicitis, 73 cases (27.04%) showed other diseases, whereas 103 cases (38.15%) showed no relevant findings. The sensitivity, specificity, positive predictive value, and negative predictive value of focused CT were 92.86%, 98.26%, 96.81%, and 96.02%, respectively.

Conclusion: For the diagnosis of acute appendicitis, CT scan range can be limited to cover from superior border of L3 to superior border of pubic symphysis.


Cartwright SL, Knudson MP. Diagnostic imaging of acute abdominal pain in adults. Am Fam Physician. 2015 Apr 1;91(7):452-9.

Guan L, Liu Z, Pan G, Zhang B, Wu Y, Gan T, et al. The global, regional, and national burden of appendicitis in 204 countries and territories, 1990-2019: a systematic analysis from the Global Burden of Disease Study 2019. BMC Gastroenterol. 2023 Feb 22;23(1):44.

Bom WJ, Scheijmans JCG, Salminen P, Boermeester MA. Diagnosis of Uncomplicated and Complicated Appendicitis in Adults. Scand J Surg. 2021 Jun;110(2):170-179.

Kambadakone AR, Santillan CS, Kim DH, Fowler KJ, Birkholz JH, Camacho MA, et al. ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update. J Am Coll Radiol. 2022 Nov;19(11S):S445-S461.

Garcia EM, Camacho MA, Karolyi DR, Kim DH, Cash BD, Chang KJ, et al. ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis. J Am Coll Radiol. 2018 Nov;15(11S):S373-S387.

Aly NE, McAteer D, Aly EH. Low vs. standard dose computed tomography in suspected acute appendicitis: Is it time for a change? Int J Surg. 2016 Jul;31:71-9.

Yun SJ, Ryu CW, Choi NY, Kim HC, Oh JY, Yang DM. Comparison of Low- and Standard-Dose CT for the Diagnosis of Acute Appendicitis: A Meta-Analysis. AJR Am J Roentgenol. 2017 Jun;208(6):W198-W207.

Haijanen J, Sippola S, Tammilehto V, Grönroos J, Mäntyoja S, Löyttyniemi E, et al. Diagnostic accuracy using low-dose versus standard radiation dose CT in suspected acute appendicitis: prospective cohort study. Br J Surg. 2021 Dec 1;108(12):1483-1490.

Corwin MT, Chang M, Fananapazir G, Seibert A, Lamba R. Accuracy and radiation dose reduction of a limited abdominopelvic CT in the diagnosis of acute appendicitis. Abdom Imaging. 2015 Jun;40(5):1177-82.

Zinsser D, Maurer M, Do PL, Weiß J, Notohamiprodjo M, Bamberg F, et al. Reduced scan range abdominopelvic CT in patients with suspected acute appendicitis - impact on diagnostic accuracy and effective radiation dose. BMC Med Imaging. 2019 Jan 11;19(1):4.

Tarulli M, Rezende-Neto J, Vlachou PA. Focused CT for the evaluation of suspected appendicitis. Abdom Radiol (NY). 2019 Jun;44(6):2081-2088.

Dowhanik A, Tonkopi E, Crocker CE, Costa AF. Diagnostic performance and radiation dose of reduced vs. standard scan range abdominopelvic CT for evaluation of appendicitis. Eur Radiol. 2021 Oct;31(10):7817-7826.

Karul M, Berliner C, Keller S, Tsui TY, Yamamura J. Imaging of appendicitis in adults. Rofo. 2014 Jun;186(6):551-8.

Davis J, Roh AT, Petterson MB, Kopelman TR, Matz SL, Gridley DG, et al. Computed tomography localization of the appendix in the pediatric population relative to the lumbar spine. Pediatr Radiol. 2017 Mar;47(3):301-305.




How to Cite

Manmanee, T. (2024). Sensitivity and specificity of focused CT for the diagnosis of acute appendicitis . Region 11 Medical Journal, 38(2). Retrieved from



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