Incidence of visualization of the normal appendix on different MRI sequences.

The purpose of this paper is to assess the incidence of visualization of the normal appendix on magnetic resonance imaging (MRI) examinations of the pelvis in a large adult population and to compare the yield of commonly used sequences. Pelvic MRI scans of 111 randomly selected patients were retrospectively reviewed by two fellowship-trained body imagers. Thirty-six cases, where the entire cecum and terminal ileum were not included in the field of view, were excluded. A normal appendix was definitively visualized in 55 of 71 patients on T1 spin echo (SE) sequences (78%). The appendix was seen on 25 of 42 (60%) half-Fourier single-shot turbo spin echo T2. Visualization rates were 42% on pre-gadolinium T1 FS GRE, 54% on post-gadolinium T1 fat-suppressed gradient echo, and 17% of short tau inversion recovery sequences. MRI is an effective modality for visualization of the normal appendix. This may have important implications in patients with abdominal or pelvic pain, as visualization of a normal appendix should exclude the possibility of acute appendicitis from the differential diagnosis.