7T imaging in progressive supranuclear palsy and behavioural variant frontotemporal dementia

Abstract

AbstractBackgroundProgressive supranuclear palsy (PSP) and behavioural variant frontotemporal dementia (bvFTD) are clinical syndromes associated with frontotemporal lobar degeneration (FTLD). Although distinct diseases, they have in common cognitive and behavioural changes, including personality, motivation and executive function. This phenotypic overlap between bvFTD and PSP is reflected in the MDS‐2017 criteria for the PSP‐F subtype (Höglinger et al., 2017), and frequent parkinsonism seen in bvFTD (Rowe, 2019). This study uses ultra‐high field MRI to identify the atrophy patterns in bvFTD and PSP, complementing neurochemical insights from spectroscopy (Murley, 2020).Method23 Healthy controls, 23 people with probable PSP, and 16 people with bvFTD underwent structural imaging with MP2RAGE sequence (0.7mm isotropic resolution) at ultra‐high field (7T) on a MAGNETOM Siemens TERRA scanner. Clinical and cognitive assessment was undertaken contemporary with imaging. Grey and white matter volumes were compared between groups using independent two‐sample t‐tests, including age and total intracranial volume as covariates of no interest. Significant effects were identified using cluster‐level statistics (p<0.05, family‐wise error corrected for multiple comparisons) above a height threshold of p<0.001 (uncorrected).ResultCompared to controls, both patients with PSP and bvFTD show significant atrophy of the cingulate gyrus, frontal gyri, and the supplementary motor cortex with the parietal and especially occipital lobe being spared (p <0.05, FWE). Patients with PSP show additional white matter atrophy of the brainstem and basal ganglia (p <0.05, FWE). Compared to PSP, patients with bvFTD show more grey matter atrophy in the inferior frontal gyrus, inferior temporal gyrus, temporal pole, as well as the right insula. Patients with PSP show more white matter atrophy of the basal ganglia, brain stem, and superior cerebellum compared to those with bvFTD (p<0.001, uncorrected).ConclusionThis is the first voxel‐based morphometry study comparing bvFTD and PSP at ultra‐high field, with higher resolution imaging than previous studies at 1.5T or 3.T. Although both classified as syndromes associated with FTLD, patients with bvFTD and PSP show both specific and complementary patterns of atrophy compared to those of healthy controls and each other.