Identification by [99mTc]ECD SPECT of anterior cingulate hypoperfusion in progressive supranuclear palsy, in comparison with Parkinson’s disease

Abstract
Progressive supranuclear palsy (PSP) is an akinetic-rigid syndrome that could be difficult to differentiate from Parkinson’s disease (PD), particularly at an early stage. [99mTc]ECD SPET could be a widely available tool to help the differential diagnosis. Purpose. We used voxel-based analysis and Computerised Brain Atlas (CBA) based Principal Component Analysis (PCA) of [99mTc]ECD SPET data to test whether: 1) specific patterns of rCBF abnormalities could differentiate PSP from Controls and PD; 2) networks of dysfunctional brain regions could be found in PSP vs. Controls and PD. Methods. Nine PD, 16 PSP patients and 10 Controls were studied with [99mTc]ECD SPET using a brain-dedicated device (Ceraspect). Voxel-based analysis was performed with Statistical Parametric Mapping (SPM2). PCA was applied to VOI data after spatial normalisation to CBA. Results. The voxel-based analysis showed hypoperfusion of the anterior cingulate and medial frontal cortex in PSP compared with Controls and PD. In PSP patients the rCBF impairment extended to pre-supplementary motor area and prefrontal cortex, areas involved in executive function and motor networks. Compared with PSP, PD patients showed a mild rCBF decrease in associative visual areas which could relate to the known impairment of visuospatial function. The PCA identified 3 principal components differentiating PSP patients from Controls and/or PD patients that included groups of cortical and subcortical brain regions with relatively decreased (anterior and posterior cingulate cortex, prefrontal cortex, and caudate) or increased (parietal cortex) rCBF, representing distinct functional networks in PSP. Conclusions. Anterior cingulate hypoperfusion seems to be an early distinct brain abnormality in PSP as compared with PD.