Assessment of whole-brain vasodilatory capacity with acetazolamide challenge at 1.5 T using dynamic contrast imaging with frequency-shifted burst.
OBJECTIVE
To determine whether whole-brain acetazolamide-induced changes in regional cerebral blood volume (rCBV) can be assessed on a conventional gradient 1.5-T MR system using 3-D dynamic susceptibility contrast-enhanced MR imaging.


METHODS
A 3-D frequency-shifted (FS) burst technique was used to assess the intravascular first pass of contrast agent. Changes in rCBV were calculated in 40 volunteers before and after acetazolamide (n = 30) or saline (n = 10) injection using customized analysis software on an independent workstation. A single-section gradient-echo technique with better spatial resolution was used in one additional volunteer to examine the effect of partial volume averaging on calculation of absolute rCBV.


RESULTS
A statistically significant increase in rCBV (gray matter = 23%, white master = 32.5%) was noted after acetazolamide compared with saline. Baseline fractional CBVs were 22% +/- 3% for gray matter and 12% +/- 2% for white matter. Partial volume averaging was probably responsible for a systematic but linear overestimation of absolute rCBV.


CONCLUSIONS
Acetazolamide-induced changes in rCBV can be assessed using 3-D dynamic susceptibility contrast-enhanced MR imaging with FS-burst on a conventional gradient 1.5-T MR system. Values obtained with this technique overestimate absolute rCBV but are systematically biased and can be used for intersubject and intrasubject ratio comparisons.
Petrella
J R
JR
Laboratory of Diagnostic Radiology Research, National Institutes of Health, Bethesda, Md 20892, USA.
DeCarli
C
C
Dagli
M
M
Duyn
J H
JH
Grandin
C B
CB
Frank
J A
JA
Hoffman
E A
EA
Theodore
W H
WH
D000086:Acetazolamide / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000098:blood supply*; D003287:Contrast Media; D004338:Drug Combinations; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D012039:Regional Blood Flow / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D014665:Vasodilator Agents; D008536:Meglumine; D004369:Pentetic Acid; D019786:Gadolinium DTPA; D000086:Acetazolamide