Dual-phase 18F-FP-CIT PET in corticobasal syndrome underlying AD pathology

Excerpt

Dual-phase 18F-FP-CIT (early and late phases) and 18F-florbetaben PET images were obtained in a 60-year-old woman who presented with a 6-month history of right involuntary movement (dystonia, myoclonus, apraxia) and cognitive decline, which is compatible with corticobasal syndrome (CBS). A dual-phase 18F-FP-CIT PET study showed hypoperfusion in the bilateral temporo-parietal cortex without involvement of the thalamus and basal ganglia in the early phase (Fig. 1A, B), but preserved dopamine transporter (DAT) binding in the late phase (Fig. 1C). 18F-florbetaben PET showed prominent accumulation of beta-amyloid plaque in frontal, temporo-parietal cortex, suggesting AD pathology (Fig. 1D–F). Brain MRI was unremarkable(Fig. 1G–I). Alzheimer’s disease (AD) is the second-most common pathology in CBS. Our observation of posterior temporoparietal hypoperfusion in the early phase of 18F-FP-CIT PET is in line with the previous FDG-PET studies in patients with CBS with in vivo biomarkers of amyloid deposition or AD pathology [1]. CBS with normal DAT binding might suggest focal cortical variants of other dementia such as AD other than CBD (corticobasal degeneration) [2]. Extranigral pathology at cortical lesion without dopaminergic deficit may contribute to CBS [3]. However, in pathologically proven CBD, some patients may have preserved DAT binding at early stage, although substantia nigral cell loss is characteristic of CBD [4]. …