Acute Nonhemorrhagic Adrenal Infarction in Pregnancy: 10-Year MRI Incidence and Patient Outcomes at a Single Institution.

OBJECTIVE: The purpose of this study was to retrospectively investigate the MRI incidence of nonhemorrhagic adrenal infarction in pregnant women undergoing MRI evaluation of acute abdominal or flank pain, assess the MRI features quantitatively, and report patient outcomes. MATERIALS AND METHODS: All abdominal MRI examinations of pregnant women with acute pain at one institution from May 2005 to April 2015 were reviewed. The adrenals were evaluated for abnormal morphologic and signal intensity characteristics described in the literature characterizing nonhemorrhagic adrenal infarction and were compared with the contralateral adrenal by paired t tests. The findings were correlated with clinical presentation. Patient demographics and outcomes were gathered from the medical record. RESULTS: Findings of nonhemorrhagic adrenal infarction were present in 5 of 379 (1.3%) examinations of four pregnant patients (mean age, 28 years; range, 20.8-33.9 years; mean gestational age, 26 weeks; range, 16-35 weeks). MRI features included lengthening (mean, 39.8 versus 21.2 mm) (p = 0.005) and increased T2 signal intensity (p = 0.001) of the infarcted adrenal with surrounding edema and without T1 signal intensity suggesting hemorrhage. No alternative diagnosis was identified. All patients presented with severe acute abdominal or flank pain on the same side as the MRI findings, tenderness to palpation, and mild leukocytosis. All women delivered healthy infants. CONCLUSION: Unilateral nonhemorrhagic adrenal infarction was identified in 1.3% of abdominal MRI examinations performed for pregnant women with acute abdominal or flank pain. Knowledge of the MRI characteristics of this entity is important for recognizing it and may prevent further potentially invasive tests, procedures, or missed diagnoses.