Quantitative regional cerebral flow measured by Tc-99M HMPAO SPECT in mood disorder

Depressed (n = 14) and remitted (n = 9) patients with mood disorder, patients with depressive disorder not otherwise specified (NOS; n = 10) and normal subjects (n = 8) underwent non-invasive and quantitative measurement of cerebral blood flow using HMPAO and SPECT in a resting state. The mean and regional cerebral blood flow (CBF) in twelve ROIs were compared among the four groups and correlations between CBF and the depressive symptoms were studies. The CBF was computed using graphical analysis on the SPECT console after a bolus injection of Tc-99m HMPAO and radionuclide angiography. The depressed group had significantly lower mCBF in the bilateral hemisphere and rCBF in all except one of the ROIs than the NOS and normal group. Significant negative correlations were found between the Hamilton scale for depression and rCBF in the bilateral lower frontal cortex after correcting for age in the mood disorder. Parallel analysis using both the quantitative and semiquantitative methods revealed that the former provided more global reduction of CBF in mood disorder. These results indicate that mean and regional CBF measured by this non-invasive method contributes to the objective evaluation of depressive symptoms. Negative correlations between HRSD and rCBF in the frontal regions indicate that frontal hypoactivity is closely related to depressive symptoms.