The clinical significance of diffusion-weighted MR imaging in infratentorial strokes.
OBJECTIVE
To study the association between diffusion-weighted imaging (DWI) characteristics and stroke etiology, stroke severity, and functional outcome in patients with infratentorial strokes.


METHODS
The authors prospectively studied 22 consecutive patients with acute infratentorial strokes. They used a blinded comparison of DWI features (number, distribution, and volume of lesions) with clinical characteristics, namely, stroke etiology (Trial of ORG 10172 in Acute Stroke Treatment [TOAST] classification), severity (NIH Stroke Scale [NIHSS]), length of stay (LOS), and functional 3-month outcome using modified Rankin Scale, Barthel Index, and a dichotomized outcome status (living at home vs institutionalization or death).


RESULTS
Acute infratentorial DWI lesions were detected in 95% (21/22) of the patients. The number (p = 0.01) and the distribution (p < 0.001) of DWI lesions were correlated with stroke etiology. Patients with cardioembolic strokes (n = 5) had more DWI lesions (8.0 +/- 6.0) than those with other stroke etiologies (n = 17; 1.3 +/- 0.9; p < 0.001). Their lesion distribution differed from that of patients with noncardioembolic strokes (p < 0.001). Clinically silent, acute DWI lesions in the anterior circulation in addition to their infratentorial lesions were visualized in 3 of 5 patients with cardioembolic stroke and in none of 17 patients without sources of cardioembolism (p < 0.001). Pure infratentorial lesions were present in 15 of 17 patients with noncardioembolic strokes and in none of 5 cardioembolic stroke patients (p < 0.001). DWI lesion volume was not correlated with NIHSS score, LOS, outcome scores, or outcome status.


CONCLUSIONS
In infratentorial strokes, multiple DWI lesions and a distribution of subsidiary, clinically silent DWI lesions in the anterior circulation suggest a cardioembolic stroke etiology. However, DWI lesion volume did not correlate with the NIHSS score and was no predictor of outcome.
Engelter
S T
ST
Neurological Clinic and Stroke Unit, University Hospital Basel, Switzerland. sengelter@uhbs.ch
Wetzel
S G
SG
Radue
E W
EW
Rausch
M
M
Steck
A J
AJ
Lyrer
P A
PA
D000328:Adult; D000368:Aged; D001925:Brain Damage, Chronic / Q000453:epidemiology / Q000209:etiology; D002531:Cerebellum / Q000098:blood supply; D005260:Female; D006331:Heart Diseases / Q000150:complications; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000473:pathology; D020766:Intracranial Embolism / Q000209:etiology / Q000473:pathology; D007902:Length of Stay; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008636:Mesencephalon / Q000098:blood supply; D008875:Middle Aged; D011149:Pons / Q000098:blood supply; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D016037:Single-Blind Method; D020521:Stroke / Q000473:pathology*; D016896:Treatment Outcome