Emergency MRI of acute pelvic pain: MR protocol with no oral contrast

The aim of this study was to evaluate the efficacy of magnetic resonance (MR) without oral contrast in the assessment of suspected acute pathologies of the pelvis in pregnant and non-pregnant patients. Sixty-seven patients who had MR of the lower abdomen and pelvis for acute abdomen were included in the study. The MR examinations were evaluated for indication of the study, type of MR sequences, and sensitivity of MR in diagnosing the disease. T2 single shot fast spin echo (SS-FSE), T2 FSE, short tau inversion recovery, pre-gadolinium T1, and post-gadolinium T1 sequences were utilized. There were 30 pregnant and two postpartum women in the study group. Positive pelvic MR findings were seen in 73% (49/67). Final diagnoses were acute appendicitis (n∈=∈12), ovarian torsion (n∈=∈6), abscess (n∈=∈3), tubo-ovarian abscess (n∈=∈2), ovarian tumor (n∈=∈2), degenerating fibroid (n∈=∈3), and perianal fistula (n∈=∈2). For acute appendicitis, sensitivity was 100% (12/12), and positive predictive value was 92% (12/13). Post-gadolinium T1-weighted sequences and T2 SS-FSE with FS were the sequences, which were most likely to best demonstrate the acute appendicitis. For ovarian torsion, the sensitivity was 86% (6/7), and positive predictive value was 100% (6/6). MR imaging is an efficacious means of diagnosing acute appendicitis, ovarian torsions, and other adnexal diseases in the acute setting. The four sequence protocol without oral contrast offers an excellent means of investigating the cause of acute lower abdominal and pelvic pain. © 2008 Am Soc Emergency Radiol.