Regional cerebral blood flow and magnetic resonance spectroscopic imaging findings in diaschisis from stroke.
OBJECTIVE
This study evaluated blood flow and metabolite changes in cerebral diaschisis from internal capsule region infarction using regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT) and 1H magnetic resonance spectroscopic imaging (MRSI). We hypothesized that complementary measures of diaschisis effects in white matter (characterized by 1H MRSI) and gray matter (characterized by changes in rCBF) can be measured and exhibit parallel changes.


METHODS
Five stroke patients and 16 normal controls underwent Tc-99m hexamethylpropyleneamine-oxime brain SPECT and 1H MRSI at 4.1 T. The metabolites N-acetyl aspartate (NAA) and creatine (Cr) were measured using 1H MRSI. The tissue content was expressed as the percent of gray or white matter in each MRSI voxel to allow comparison of the differential effects of diaschisis in gray and white matter tissue types. The blood flow and metabolite changes were evaluated at superior cerebral regions distant from the stroke to allow a measure of diaschisis relatively unconfounded by their expected changes in the infarction region.


RESULTS
The rCBF SPECT data in stroke patients showed a perfusion defect, with size ranging from 1.23 cc to 10.23 cc, in the region of cortical diaschisis. 1H MRSI showed increased Cr/NAA ratios in regions of white matter diaschisis. There was a tendency for larger rCBF defect size to be associated with greater increases in Cr/NAA values in the same diaschitic cerebral hemisphere, ipsilateral to the infarction.


CONCLUSIONS
Diaschisis ipsilateral to stroke in white matter can be characterized by 1H MRSI, and diaschisis ipsilateral to stroke in cortical gray matter regions can be characterized by changes in rCBF. The tendency for greater reductions in cortical rCBF values to be associated with increased Cr/NAA values in the same diaschitic cerebral hemisphere implies that a relationship exists between rCBF reductions in gray matter and abnormal changes in white matter subservient to it.
Chu
Wen-Jang
WJ
Division of Nuclear Medicine, Department of Radiology, University of Alabama at Birmingham Medical Center, Birmingham, Ala 35233, USA.
Mason
Graeme F
GF
Pan
Jullie W
JW
Hetherington
Hoby P
HP
Liu
Hong-Gang
HG
San Pedro
Elmer C
EC
Mountz
James M
JM
D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D002544:Cerebral Infarction / Q000175:diagnosis / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D003401:Creatine / Q000378:metabolism; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000209:etiology; D011237:Predictive Value of Tests; D012016:Reference Values; D020521:Stroke / Q000175:diagnosis* / Q000503:physiopathology*; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D001224:Aspartic Acid; D019690:Technetium Tc 99m Exametazime; C000179:N-acetylaspartate; D003401:Creatine