Diffusion-weighted imaging in the setting of diffuse cortical laminar necrosis and hypoxic-ischemic encephalopathy.
OBJECTIVE
As is the case for CT scans, MR images may occasionally appear deceptively normal unless proper windowing is used. We sought to illustrate the necessity for proper windowing and for assessing the gray-white matter differentiation on diffusion-weighted (DW) images in the setting of hypoxic-ischemic encephalopathy.


METHODS
Six comatose patients (age range, 34-56 years) underwent MR imaging in the early phase (range, 1-5 days) after severe anoxic insult. T2-weighted, turbo fluid-attenuated inversion-recovery, and DW images were obtained in all six patients, with contrast-enhanced T1-weighted images obtained in four and apparent diffusion coefficient (ADC) maps in five of the six patients.


RESULTS
At presentation, each of the six patients had symmetric, uniform hyperintensity in the cortex (mean ADC, 0.35 x 10(-3) mm(2)/s) relative to the white matter (mean ADC, 0.91 x 10(-3) mm(2)/s) on DW images. Each also had a poor outcome: brain death in four patients and a permanent vegetative state in two patients.


CONCLUSIONS
The appearance of the MR images in the setting of diffuse cortical laminar necrosis can be deceptive to the unwary radiologist. The key to correct interpretation is proper windowing and the marked gray-white matter differentiation on spin-echo images but best seen on properly windowed DW images in the early subacute phase. This appearance also implies an extremely poor outcome, either a permanent vegetative state or brain death.
McKinney
Alexander M
AM
University of Minnesota Medical School, Department of Radiology, Box 292, 420 Delware St SE, Minneapolis, MN 55455, USA.
Teksam
Mehmet
M
Felice
Ross
R
Casey
Sean O
SO
Cranford
Ronald
R
Truwit
Charles L
CL
Kieffer
Stephen
S
D000328:Adult; D001926:Brain Death; D002540:Cerebral Cortex / Q000473:pathology*; D003128:Coma / Q000175:diagnosis / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D018458:Persistent Vegetative State / Q000209:etiology; D014057:Tomography, X-Ray Computed