High-resolution ultrahigh-field MRI of stroke.
BACKGROUND
Ultrahigh-field MRI at 8 T offers unprecedented resolution for imaging brain structures and microvasculature.


OBJECTIVE
The aim of this study is to apply high-resolution MRI for stroke imaging and to characterize findings at 1.5 and 8 T.


METHODS
Seventeen subjects with minor ischemic infarcts were studied using T2-weighted gradient echo (GE) and rapid acquisition with relaxation enhancement (RARE) images at 8 T with resolution up to 200 microm. In 10 subjects, T1- and T2-weighted fast spin echo (FSE) and fluid-attenuated inversion recovery (FLAIR) images were also acquired at 1.5-T MRI.


RESULTS
The 8-T images showed infarcts as sharply demarcated areas of high-signal intensity (n=21) and revealed more infarctions than 1.5-T images (n=14) (P<.003). The low-signal intensity areas that surrounded infarctions were suggestive of hemosiderin deposits. The 8-T characteristics of microvessels terminating within the infractions were distinct from normal vasculature. The 8-T images revealed an angioma at the site of a second stroke, not apparent on 1.5-T images.


CONCLUSIONS
Ultrahigh-field MRI at 8 T is feasible for stroke imaging. The 8-T MRI visualized infarcts and microvasculature with high resolution, revealing infarcts and vascular pathologies that were not apparent at 1.5 T.
Novak
Vera
V
Department of Medicine/Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. vnovak@caregroup.harvard.edu
Abduljalil
A M
AM
Novak
P
P
Robitaille
P M
PM
D000328:Adult; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D020521:Stroke / Q000473:pathology*
D003287:Contrast Media