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Assessment of cerebral blood flow reserve using functional magnetic resonance imaging
Author(s) -
Hedera Peter,
Lai Song,
Lewin Jonathan S.,
Haacke E. Mark,
Wu Dee,
Lerner Alan J.,
Friedland Robert P.
Publication year - 1996
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880060504
Subject(s) - cerebral blood flow , magnetic resonance imaging , acetazolamide , signal (programming language) , nuclear magnetic resonance , blood flow , medicine , blood oxygen level dependent , signal averaging , neuroimaging , nuclear medicine , radiology , cardiology , physics , computer science , signal transfer function , digital signal processing , analog signal , psychiatry , programming language , computer hardware
Imaging of activated brain areas based on changes of blood deoxyhemoglobin levels is now possible with MRI. Acetazolamide (ACZ) increases cerebral blood flow (CBF) without changing cerebral oxygen consumption; this results in signal changes observed in gradient echo MR images from the areas with an increase in CBF. We assessed signal changes after ACZ application in seven healthy subjects with a conventional 1.5‐T MRI scanner. The susceptibility‐sensitized three‐dimensional fast low‐angle shot (FLASH) sequence was used to visualize signal changes induced by ACZ. We analyzed anatomic localization of different ranges of detected signal changes. ACZ caused significant signal changes in the gray matter and at the edge of the cerebral cortex, the latter corresponding to draining surface veins. No significant differences were seen among different brain areas within the same slice. Using the maximum intensity projection technique, we were able to partially separate signal changes originating in draining veins from signal originating in the gray matter microvasculature. Signal changes from the microvessels reflect cerebrovascular reserve. Blood‐oxygen‐level‐dependent (BOLD) based MRI can evaluate CBF reserve with high spatial and temporal resolution. To assess cerebrovascular reserve, it is necessary to separate signal changes originating in large vessels from signal from brain microvasculature.