Pregnancy-Associated Renal Cortical Necrosis and Nonenhanced Functional Magnetic Resonance Imaging: A Case Series

RATIONALE & OBJECTIVE: Pregnancy-associated renal cortical necrosis is a critical illness with a poor prognosis. We aimed to describe the clinical and magnetic resonance imaging (MRI) characteristics of a case series of patients with acute kidney injury in the setting of pregnancy-associated renal cortical necrosis. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Seventeen patients from a single center diagnosed by nonenhanced functional MRI and/or kidney pathology. RESULTS: All patients presented with postpartum acute kidney injury stage 3. Of the 17 patients, 15 (88%) had pregnancy-associated atypical hemolytic uremic syndrome, 11 (65%) had postpartum hemorrhage, 7 (41%) had preeclampsia/hemolysis elevated liver enzymes low platelet count syndrome, and 4 (24%) had disseminated intravascular coagulation. On T2-weighted MRI, the diffuse phenotype showed outer cortex swelling in the early phase, with a dark signal rim involving the inner cortex and Bertin column, which became more apparent over time along with cortical thinning, substantially decreasing T2 signal intensity. The focal phenotype showed focally distributed hypointense signals in the cortex. After 8-101 (median: 60) months of follow-up, 4 individuals had estimated glomerular filtration rates ≥60 mL/min/1.73 m(2), 6 had estimated glomerular filtration rates of 15-60 mL/min/1.73 m(2), and 7 had kidney failure requiring kidney replacement therapy. The diffuse phenotype was present in all of the individuals who remained kidney replacement therapy dependent. LIMITATIONS: Retrospective study; small sample size. CONCLUSIONS: Different forms of pregnancy-associated thrombotic microangiopathy were the major causative diseases in our pregnancy-associated renal cortical necrosis case series. Nonenhanced functional MRI may provide valuable data for establishing diagnosis and kidney prognosis.