Prognostic value of brain diffusion-weighted imaging after cardiac arrest.
OBJECTIVE
Outcome prediction is challenging in comatose postcardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion-weighted magnetic resonance imaging (DWI) during the first week.


METHODS
Consecutive comatose postcardiac arrest patients were prospectively enrolled. AWI data of patients who met predefined specific prognostic criteria were used to determine distinguishing apparent diffusion coefficient (ADC) thresholds. Group 1 criteria were death at 6 months and absent motor response or absent pupillary reflexes or bilateral absent cortical responses at 72 hours or vegetative at 1 month. Group 2 criterion was survival at 6 months with a Glasgow Outcome Scale score of 4 or 5 (group 2A) or 3 (group 2B). The percentage of voxels below different ADC thresholds was calculated at 50 x 10(-6) mm(2)/sec intervals.


RESULTS
Overall, 86% of patients underwent DWI. Fifty-one patients with 62 brain DWIs were included. Forty patients met the specific prognostic criteria. The percentage of brain volume with an ADC value less than 650 to 700 x 10(-6)mm(2)/sec best differentiated between Group 1 and Groups 2A and 2B combined (p < 0.001), whereas the 400 to 450 x 10(-6)mm(2)/sec threshold best differentiated between Groups 2A and 2B (p = 0.003). The ideal time window for prognostication using DWI was between 49 and 108 hours after the arrest. When comparing DWI in this time window with the 72-hour neurological examination, DWI improved the sensitivity for predicting poor outcome by 38% while maintaining 100% specificity (p = 0.021).


CONCLUSIONS
Quantitative DWI in comatose postcardiac arrest survivors holds promise as a prognostic adjunct.
Wijman
Christine A C
CA
Stanford Stroke Center, Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA 94304, USA. cwijman@stanford.edu
Mlynash
Michael
M
Caulfield
Anna Finley
AF
Hsia
Amie W
AW
Eyngorn
Irina
I
Bammer
Roland
R
Fischbein
Nancy
N
Albers
Gregory W
GW
Moseley
Michael
M
D000328:Adult; D000368:Aged; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D005240:Feasibility Studies; D005260:Female; D006323:Heart Arrest / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D055815:Young Adult