Evaluation of initial diffusion-weighted image findings in acute stroke patients using a semiquantitative score.
OBJECTIVE
We evaluated the usefulness of rating diffusion-weighted images (DWI) using a semiquantitative score modified from the Alberta Stroke Programme Early CT Score (ASPECTS) to predict deterioration of neurological symptoms in patients with hyperacute ischemic stroke who had undergone thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA).


METHODS
We examined 22 patients with acute stroke (14 men, 8 women, mean age 72.5 years) treated with intravenous rt-PA. All were assessed using the National Institutes of Health Stroke Scale (NIHSS) and underwent emergent magnetic resonance (MR) imaging within 3 hours and 24 hours of stroke onset. Patients were divided into a deteriorated group (16 patients), in which NIHSS scores were increased after thrombolysis, and a non-deteriorated group (6 patients). We compared the DWI score, ASPECTS, and volume of hyperintense ischemic lesion on DWI (DWI volume) of the 2 groups and examined correlations between these scores and initial NIHSS score or DWI volume.


RESULTS
The DWI score and ASPECTS tended to be lower in the deteriorated group than the non-deteriorated group. In addition, with a cutoff value<or=7, the DWI score could discriminate the deteriorated group from the non-deteriorated group with a sensitivity of 50% and specificity of 87.5%, whereas for ASPECTS, sensitivity was 50% and specificity, 81.2%. The DWI score, ASPECTS, and DWI volume had no correlation with NIHSS score but weak negative correlations with the DWI volume (P<0.01; Spearman's test). Comparing initial NIHSS score with each DWI score and DWI volume, the non-deteriorated group tended to have higher DWI scores and smaller DWI volumes than the deteriorated group, but there was no statistical difference between initial NIHSS and DWI scores. Though the DWI score was not statistically different, the threshold would be set to 6 points or above. Comparing initial DWI score with volume, patients with low DWI scores tended to show large variation in DWI volume and patients with small DWI volume showed large variation in DWI scores. There was no relation between hemorrhagic change and symptoms in either group.


CONCLUSIONS
The semiquantitative DWI score easily evaluated extent of acute ischemic lesion on DWI and might be used to predict patient outcome after thrombolytic therapy more accurately than ASPECTS or DWI volume.
Morita
Naomi
N
Department of Radiology, School of Medicine, University of Tokushima, Japan. nmorita@clin.med.tokushima-u.ac.jp
Harada
Masafumi
M
Uno
Masaaki
M
Matsubara
Shunji
S
Nagahiro
Shinji
S
Nishitani
Hiromu
H
D000368:Aged; D000369:Aged, 80 and over; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D020521:Stroke / Q000188:drug therapy / Q000473:pathology*; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016896:Treatment Outcome
D010959:Tissue Plasminogen Activator