[The temporal changes in the diffusion coefficients in stroke].
OBJECTIVE
Analysis of temporal changes of ADC values at different stages after stroke.


METHODS
The original images of all scans were evaluated and a region of interest analysis was performed on ADC (apparent diffusion coefficient) maps. 92 patients with symptoms of ischemic stroke were examined at 1.5 Tesla (ACS-NT, Philips Medical Systems). The study protocol included a navigated multishot SE-EPI DWI (b = 0, 189, 750 s/mm-2, TE = 120/140 ms, delta/delta = 49/60 ms), a GraSE (TR/TE = 3500/90 ms) and a FLAIR-TSE (TR/TE/TI = 6000/150/2000 ms) sequence. 8 patients had regular follow-ups. All patients had an additional CT scan.


RESULTS
In hyperacute stroke (< 6 h, n = 10) the relative ADC of the infarct core dropped to about 50% and reached a minimum in the acute state (6-48 h, n = 14) during the next few hours. In subacute stroke (< 3 weeks, n = 29) the ADC began to rise significantly (p = 0.001) back to normal values and reached (p < 10(-4)) values similar to cerebrospinal fluid in the chronic state (> 3 weeks, n = 20). The combined use of DWI and conventional MRI improved the diagnostic information in 16% of all MR examination beyond the hyperacute assessment.


CONCLUSIONS
By means of the ADC-values the age of stroke can be determined. Infarcts at different stages can be readily diagnosed with the combined use of DWI, FLAIR-TSE and GraSE. Pitfalls of DWI and conventional imaging can be avoided.
Flacke
S
S
Radiologische Universitätsklinik Bonn. flacke@uni.bonn.de
Urbach
H
H
Keller
E
E
Hartmann
A
A
Block
W
W
Träber
F
F
Gieseke
J
J
Schild
H H
HH
D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000175:diagnosis; D002544:Cerebral Infarction / Q000175:diagnosis; D002561:Cerebrovascular Disorders / Q000175:diagnosis*; D004058:Diffusion; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors