According to a study recently published in the American Journal of Roentgenology (AJR), researchers from Brigham and Women's Hospital in Boston and the Lehigh Valley Health Network in Allentown, Pennsylvania, have found that unilateral nonhemorrhagic adrenal infarction may be uncommon in pregnant women who have experienced acute abdominal or flank pain.  

For pregnant women, the study may reduce the number of invasive tests, surgery or missed diagnoses, the authors wrote.  

"Because of the physiologic changes of pregnancy, such as increased blood volume, decreased production of anticoagulant factors and venous stasis due to mass effect by the gravid uterus, pregnancy itself increase the risk of venous thromboembolism approximately fivefold," said lead author Shahar A. Glomski, MD, from the department of radiology at Brigham and Women's Hospital, and colleagues. "This makes pregnant women a population uniquely susceptible to adrenal infarction." 

Abdominal MRI exams of 379 pregnant women who reported acute pain from May 2005 to April 2015 were reviewed by two radiology residents. Specifically, adrenals were evaluated and compared for abnormal morphologic and signal intensity characteristics. Patient age, gestational age at the time of MRI examination, present symptoms, medical history, physical examination findings, laboratory examinations performed, previous imaging findings, treatment, pregnancy outcome and follow-up imaging findings were included in the final data. 

Researchers found nonhemorrhagic adrenal infarction present in five of 379 MRI exams (1.3 percent). The four women, with an average age of 28 years old and an average gestational age of 26 weeks, still delivered healthy infants. 

"MRI features included lengthening and increased T2 signal intensity of the infarcted adrenal with surrounding edema and without T1 signal intensity suggesting hemorrhage," the researchers wrote. 

Lastly, researchers noted that the diagnosis of adrenal infarction not only be clinically suspected in pregnant women who report having acute abdominal or flank pain, but in pregnant women vulnerable to developing thrombosis or who have had surgery that could lead to such diagnosis. 

"Because the use of MRI in the evaluation of pregnant women continues to increase, radiologists need to increase their awareness of nonhemorrhagic adrenal infarction to be able to recognize it based on increased size and t2 signal intensity of the adrenal with surrounding retroperitoneal edema," the researchers concluded. "An effective MRI examination of a pregnant woman is most likely to lead to eh correct diagnosis if the adrenals are fully included in the FOV and the protocol includes T2-weighted sequences with fat saturation, ideally in more than one imaging plane."