Measurement of mean cerebral blood flow using SPECT and dementia rating scales in the memory clinic

We investigated the association between mean cerebral blood flow (mCBF) values using single photon emission computed tomography (SPECT) and cognitive performance scores of three dementia rating scales (ADAS, MMSE, HDS-R). Mean CBF was measured by the 123I-IMP-ARG method in a selected group of 51 out-patients aged 41 to 90 years and by the 99mTc-ECD method in the other group of 57 out-patients aged 51 to 91 years. Simple regressions were calculated for each of the neuropsychological clusters and mCBF values. In 123I-IMP-ARG-SPECT study, there was a significant correlation between the mCBF values and HDS-R scores (R=0.37, p=0.01). 99mTc-ECD-SPECT study revealed statistically significant correlations between the mCBF values and ADAS scores (R=-0.48, p<0.001), MMSE scores (R=0.47, p<0.001), and HDS-R scores (R=0.46, p<0.001). Both 123I-IMP-ARG-SPECT study and 99mTc-ECD-SPECT study showed the progressive declines of mCBF with advancing cognitive dysfunctions. Using the cut-off point study (23/24 scores in MMSE and 20/21 scores in HDS-R), we have found that the patients with cognitive dysfunctions had lower mCBF values than the patients with those in each group of aged 60-69 years, 70-79 years, and 80-89 years. However, the difference of mCBF values between the groups with cognitive dysfunctions and without those had decreased gradually with advancing age. The present study suggests that SPECT can provide important functional informations to assess the cognitive impairment in patients with the memory disturbance. (author)