[Quantitative measurements of regional cerebral blood flow using technetium-99m-L,L-ECD SPECT activated with acetazolamide: fundamental study of measurement's accuracy, comparison with 123I-IMP ARG method].

We measured regional cerebral blood flow before and after acetazolamide administration using a serial noninvasive method with 99mTc-ECD developed by Matsuda and Takeuchi et al., and compared the accuracy of measured values with those obtained by the conventional 123I-IMP ARG method. When the regional cerebral blood flow was measured for 80 brain regions in 5 subjects without scatter correction, a differential of 0.5 +/- 8.4% was obtained between values measured before and after physiological saline administration as a placebo. A differential of -0.2 +/- 12.6% was obtained when the same regions were measured with scatter correction. These findings indicated that placebo administration did not affect measured values, regardless of whether scatter correction was performed. When 64 regions in 4 subjects at rest were measured on two successive days, a differential of -1.1 +/- 9.0% was obtained between the values measured on the two days. A differential of -4.0 +/- 11.7% was obtained for the same regions following acetazolamide administration. These findings showed that measurements were reproducible both when subjects were at rest and when they were administered acetazolamide. The above two methods were used for measurement of 80 brain regions in the same 5 subjects for comparison. Measurements of subjects at rest and with acetazolamide administration were performed on separate days. The regression line y = 0.99x + 1.47, r = 0.80, was obtained for the subjects at rest, and y = 0.86x + 7.76, with r = 0.76, for the subjects following acetazolamide administration. These findings demonstrated a good correlation between the values obtained using the two methods. The values obtained using the method of Matsuda and Takeuchi et al., before and after acetazolamide administration were thus consistent with those reported previously using the conventional method, and the former method proved to be both simple and reliable.