Regional cerebral blood flow distributions in normal volunteers:: Dynamic susceptibility contrast MRI compared with 99mTc-HMPAO SPECT

Purpose: Relative regional cerebral blood flow (rCBF) at rest was measured in 44 volunteers using both dynamic susceptibility contrast (DSC) MRI and Tc-99m-HMPAO SPECT on the same day. Method: In MRI, a Gd-DTPA-BMA contrast agent bolus (0.3 mmol/kg body wt) was monitored with a simultaneous dual FLASH pulse sequence (time resolution 1.5 s). MRI-based rCBF images were calculated by singular value decomposition-based deconvolution of the measured tissue concentration-time curve with an arterial input function from a small artery within the imaging slice. In the SPECT investigation, 900 MBq of Tc-99m-HMPAO was injected intravenously. Relative rCBF in gray matter in the thalamus and in frontal white matter was determined. Results: The ratio of relative rCBF in gray matter to relative rCBF in white matter was 2.21 +/- 0.57 using MRI and 2.24 +/- 0.54 using SPECT (mean +/- SD). Conclusion: Relative rCBF maps from DSC MRI and Tc-99m-HMPAO SPECT showed good agreement, and the MRI-based rCBF ratio correlated with the corresponding SPECT-based ratio (r = 0.79, p < 0.0000006).