Comparative quantitation of cerebral blood volume: SPECT versus PET

Quantification of cerebral blood volume (CBV) measured by SPECT has been used for evaluation of cerebral hemodynamics in patients with cerebrovascular diseases. The accuracy of such quantification, however, has not been validated with PET. Methods: CBV was assessed using SPECT and in vitro ^99mTc-labeled red blood cells and PET with the ¹⁵O steady-state inhalation method and C¹⁵O. In 23 patients with carotid artery disease, we measured hemispheric (including cortical and subcortical areas) CBV, and in 11 patients, we measured regional CBV in small cortical regions. We further evaluated the interhemispheric and inter-regional asymmetry of CBV with both methods. Results: Quantitative values of both hemispheric and regional CBV measured by SPECT were significantly correlated with those measured by PET in the same patients. There was a significant correlation between the side-to- side asymmetry of CBV for both methods. Conclusion: This study demonstrates usefulness and the accuracy of SPECT for quantitative CBV assessment in comparison with the less widely available PET procedures.