Li-tal Pratt MD, Presenter: Nothing to Disclose

Prakash Muthusami MBBS, MD, Abstract Co-Author: Nothing to Disclose

Aideen Moore, Abstract Co-Author: Nothing to Disclose

William Halliday, Abstract Co-Author: Nothing to Disclose

Adrian James, Abstract Co-Author: Nothing to Disclose

Blake Papsin, Abstract Co-Author: Nothing to Disclose

Susan I. Blaser MD, Abstract Co-Author: Nothing to Disclose

Abnormal signal and volume loss within globi pallidi and subthalamic nuclei reflective of neuronal apoptosis are present on MRI studies of chronic bilirubin encephalopathy (BE) patients. Although hippocampal signal changes and atrophy are uncommonly reported, we noted that the hippocampus is frequently abnormal as well. We retrospectively evaluated MRI studies of patients with chronic BE, providing qualitative/quantitative in vivo hippocampus assessment and imaging/pathologic specimens illustrations. We also assessed interval volumetric MRI hippocampal measurements between neonatal and post-neonatal periods.

We reviewed 79 MRI studies of 44 children with a history of neonatal BE. The patients were divided into two groups: (1=acute disorder) Neonates (<1 month old) with increased bilirubin levels or encephalopathy (mean/SD age, 39/3 weeks GA) and (2=chronic disorder) Infants (≥1 month old) and children imaged for movement disorders or auditory neuropathy in whom features of BE were found (mean/SD age, 27 /30 months). Imaging studies were evaluated qualitatively for hippocampal size and signal by two reviewers (consensus for final results); and quantitatively, by performing volumetric measurements of the hippocampi using a computerized segmentation method (Analyze 11.0). Comparison of hippocampal volumetric measurements was performed with 61 age-matched control patients imaged for unrelated skin lesions or headaches. 

Hippocampal atrophy was observed in 34/57 (60%) of group 2 patients. Abnormal T2 hyperintense hippocampal signal was observed in 31/57 (54%), while hippocampal signal was normal in controls. Hippocampal volumes in group 1 neonates were similar to age-matched controls (mean/SD 939/201 and 983/185 respectively, P=0.35). Comparison between group 2 patients and age-matched controls measurements over time demonstrated a decrease in hippocampal volume (mean/SD 1559/446 and 2360/522, respectively, P<0.01).  

Hippocampal involvement in BE is common, leading to sclerosis (chronic volume loss and signal abnormalities) in group 2 patients, suggesting progression of hippocampal atrophy over time in this population. 

Bilirubin encephalopathy (BE) has an impact on learning and memory, quantitative and qualitative hippocampal assessment on MRI studies may provide additional tools for cognitive evaluation in BE survivors.

Pratt, L, Muthusami, P, Moore, A, Halliday, W, James, A, Papsin, B, Blaser, S, Evaluation of the Hippocampus in Survivors of Bilirubin Encephalopathy.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016078.html