Martin E. O'Malley MD, Presenter: Nothing to Disclose

Fawaz Saud Alharbi MBBS, MD, Abstract Co-Author: Nothing to Disclose

Tanya Punita Chawla MBBS, Abstract Co-Author: Nothing to Disclose

Hadas Moshonov PhD, Abstract Co-Author: Nothing to Disclose

To determine appropriate anatomic coverage for CT following inconclusive or nondiagnostic US for possible appendicitis.

This retrospective study included 99 patients with possible appendicitis with inconclusive or nondiagnostic US followed by CT. Two radiologists reviewed the CT scans and determined superior and inferior anatomic coverage required to diagnose or exclude appendicitis and diagnose alternative causes. This “targeted” coverage was used to estimate potential reduction in anatomic coverage compared to standard abdominal/pelvic CT.

Study group included 99 patients; 83 women, 16 men; mean age 32 (median, 29; range 18-73) years. On CT, each reviewer identified normal appendix, no alternative diagnosis in 47 (48%) and 45 (45%); appendix not seen, no alternative diagnosis in 7 (7%) and 5 (5%); equivocal appendicitis in 5 (5%) and 2 (2%); appendicitis in 19 (19%) and 22 (22%); and alternative diagnosis in 21 (21%) and 25 (25%) patients, respectively (Kappa coefficient 0.675, substantial agreement). To confidently diagnose or exclude appendicitis or identify an alternative diagnosis, anatomic coverage would be from superior border of L2 to superior border of pubic symphysis for both reviewers. If this targeted rather than standard coverage was used, the anatomic coverage would be reduced by 30-55% (mean 39%, median 40%) with a similar reduction in dose.

When CT is performed for appendicitis following inconclusive or nondiagnostic US, targeted anatomic coverage should be from superior border of L2 to superior border of pubic symphysis. Targeted anatomic coverage would result in a significant reduction in exposure to ionizing radiation compared to standard CT.

When CT is performed for appendicitis following inconclusive or nondiagnostic US, targeted anatomic coverage rather than standard anatomic coverage can be used resulting in a significant reduction in exposure to ionizing radiation.

O'Malley, M, Alharbi, F, Chawla, T, Moshonov, H, CT Following US for Possible Appendicitis: Anatomic Coverage.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14004649.html