Abstract
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Objectives Perfusion brain SPECT is currently used in the work-up of patients with cognitive impairments. Although widely available, SPECT has been reported to be significantly less sensitive than 18F-FDG-PET. Optimization of SPECT imaging parameters using nonuniform attenuation correction (NUAC) and scatter correction (SC) might improve the accuracy of the method. The current study assesses the effect of X-ray CT-based NUAC and triple energy window (TEW) SC on brain SPECT imaging analysis compared to widely used Chang uniform (U) AC.
Methods Resting state 99mTc-ECD-SPECT-CT was acquired in 31 consecutive patients with memory complaints. CT-NUAC+TEW-SC and Chang-UAC (coefficient m=0.09cm-1 taking into account the AC and the SC) was successively applied. Images were coregistred and normalized using default SPECT template supplied with statistical parametric mapping (SPM2). A paired-test statistic image for the contrast condition effect was then reconstructed. A voxel-level threshold of T=6.82, (P<0.001) corrected for multiple comparisons and an extent threshold higher than 100 voxels were used.
Results Regional cerebral blood flow (rCBF) obtained with CT-NUAC+TEW-SC method was significantly lower in frontal white matter and fronto-temporal cortex than with Chang-UAC m=0.09 method.
Conclusions Results of former studies suggest that CT-NUAC+TEW-SC is the most accurate method to estimate rCBF. The present study indicates that UAC may underestimate subtle rCBF abnormalities in fronto-temporal regions. Correlations between rCBF measured using CT-NUAC+TEW-SC method and clinical data need to be evaluated