Clinical Utility of Computed Tomography and Magnetic Resonance Imaging for Diagnosis of Posterior Reversible Encephalopathy Syndrome after Stem Cell Transplantation in Children and Adolescents.

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome characterized by vision changes, altered mental status, and seizures, typically caused by an acute rise in blood pressure. PRES has been reported after hematopoietic stem cell transplantation (HSCT) in association with hypertension from calcineurin inhibitors and corticosteroids. The imaging evaluation of PRES after HSCT in children and young adults has not been well described. We performed a retrospective review of all HSCT recipients presenting to the intensive care unit with new neurologic symptoms. A neuroradiologist reviewed all radiologic images and compared computed tomography (CT) versus magnetic resonance imaging (MRI) findings indicative of diagnosis of PRES. Alternative imaging diagnoses explaining the patients' symptoms were also recorded. Fifty-four transplant recipients were admitted to the intensive care unit with new neurologic symptoms. Thirty-nine percent (21 of 54) of subjects had imaging findings consistent with PRES, 24% (13 of 54) had imaging findings consistent with an alternative diagnosis, 9% (5 of 54) had a nonspecific finding, and 28% (15 of 54) had no acute imaging findings. PRES was diagnosed at a median of 49 days (interquartile range, 29 to 94) after HSCT. The presenting symptom for the majority of patients with PRES was seizures (86%), whereas 14% presented with acute encephalopathy. Ninety-five percent of subjects diagnosed with PRES (20 of 21) underwent a head CT as their initial imaging evaluation. CT scan was diagnostic of PRES in 40% (8 of 20). Subsequently, 16 patients underwent brain MRI with 12 additional patients being diagnosed with PRES on MRI. The median time elapsed between negative CT and a positive MRI examination was 20 hours (range, 3.6 hours to 9 days). CT serves as an excellent screening test for acute pathology, such as intracranial hemorrhage; however, it lacks sensitivity for the diagnosis of PRES. Patients with clinical symptoms suggestive of PRES who have a negative CT should be treated appropriately for PRES and should undergo MRI of the brain as soon as clinically stable to confirm the diagnosis.