Role of Abdominal Ultrasound and Magnetic Resonance Imaging in Pregnant Women Presenting With Acute Abdominal Pain

Background and Purpose: Abdominal pain during pregnancy is quite common; however, surgical pathology such as acute appendicitis as a cause of such pain is not. Diagnostic tests used in addition to history and physical examination (PE) are ultrasound (US) and magnetic resonance imaging (MRI). We elected to find the role of these tests in pregnant patients who presented to our emergency department with acute abdominal pain. Materials And Methods: Retrospective analysis of 136 pregnant women with acute abdominal pain presented to the emergency department (ED). We reviewed PE, US, MRI, gestational age, comorbid conditions, and length of stay. Statistical analysis was done using student's t-test and chi-square test. Institutional review board approval was obtained. Results: Mean age was 26 (+/- 4.6) and the mean gestational age was 24 (+/- 9.9) weeks. Of those patients, there were 81 patients who had an US and MRI performed. The US was positive in 16 patients, while the MRI was positive in 25 patients. Three patients went for appendectomy. The US sensitivity was 0% and specificity 79%. Positive predictive value for US was 0% and negative predictive value was 95%, which was less than 100%. The MRI likelihood ratios were calculated for each test's clinical application and demonstrated that the US test result was indeterminate for ruling in and for ruling out appendicitis while the MRI allowed for high ability to rule out the disease. Conclusion: In pregnant women with acute abdominal pain and a positive PE highly suggestive of surgical pathology, US had limited value and patients should proceed to MRI.