Imaging of Acute Appendicitis in Adults: Current Practices in Pregnant Women

Abstract

Appendicitis is the most common non-obstetric surgical diagnosis made during pregnancy and is the most frequent indication for emergency surgical intervention. Swift and accurate diagnosis of appendicitis greatly impacts these pregnancy outcomes. For these reasons, imaging has become central to the diagnosis of appendicitis in the pregnant patient. Current recommendations for evaluation of appendicitis in pregnant women involve initial imaging with ultrasound. Ultrasound is known to be safe in pregnancy and is routinely used as the first line imaging modality to identify the source of abdominal pain in the pregnant patient. If the diagnosis remains inconclusive, a thoughtful conference with referring clinicians should help guide the radiologist’s next imaging modality of choice. MRI is preferable to CT given radiation concerns. The MR findings of appendicitis include a dilated, thick walled blind-ending tubular structure measuring >7 mm with periappendiceal stranding and inflammation. Periappendiceal inflammatory changes, best seen on T2-weighted imaging, correspond to edema surrounding the inflamed appendix. The use of gadolinium should be avoided in pregnancy. If MRI is unavailable, CT may be used although radiologists should make all efforts to reduce dose during this examination. Dose reduction recommendations include reduction of kilovoltage for smaller patients, decreasing milliamperage, increasing allowable noise, and taking care to limit the field of view and avoid multiple phases.