[¹⁸F]-FDopa positron emission tomography imaging in corticobasal syndrome

First, to investigate the patterns of [¹⁸F]-FDOPA positron emission tomography imaging in corticobasal syndrome using visual and semi-quantitative analysis and to compare them with patterns found in Parkinson's disease and progressive supranuclear palsy. Then, to search for correlations with clinical features and [¹⁸F]-FDG positron emission tomography imaging.

27 corticobasal syndrome patients who underwent [¹⁸F]-FDOPA positron emission tomography imaging were retrospectively studied. They were compared to 27 matched Parkinson's disease patients, 12 progressive supranuclear palsy patients and 53 normal controls. Scans were visually assigned to one of the following patterns: normal; unilateral homogeneous striatal uptake reduction; putamen uptake reduction with putamen-caudate gradient. A semi-quantitative analysis of striatal regional uptake and asymmetry was performed and correlated to clinical features and [¹⁸F]-FDG positron emission tomography patterns.

[¹⁸F]-FDOPA positron emission tomography appeared visually abnormal in only 33.5% of corticobasal syndrome patients. However, semi-quantitative analysis found putaminal asymmetry in 63%. Striatal uptake was homogeneously reduced in both putamen and caudate nucleus in corticobasal syndrome patients unlike in Parkinson's disease and progressive supranuclear palsy. No correlation was found between [¹⁸F]-FDOPA positron emission tomography and clinical features. Half of corticobasal syndrome patients presented a corticobasal degeneration pattern on [¹⁸F]-FDG positron emission tomography.  CONCLUSION: [¹⁸F]-FDOPA positron emission tomography can often be normal in corticobasal syndrome patients. Semi-quantitative analysis is useful to unmask a significant asymmetry in many of them. Homogeneous striatal uptake reduction contralateral to the clinical signs is highly suggestive of corticobasal syndrome. This finding can be helpful to better characterize this syndrome with respect to Parkinson's disease and progressive supranuclear palsy.