High resolution probabilistic in-vivo atlas of Nigrosome 1

Iron accumulation in Nigrosome 1 (N1) may represent an important biomarker in neurodegenerative disorders but its small dimension and the vanishing swallow tail sign in patients make the segmentation of this region challenging. We propose a probabilistic atlas of N1 created on a multimodal (T1-w and T2*-w) template using ROIs that were manually drawn on 0.6mm-isotropic T2*-weighted images of twenty healthy subjects. Its usability and accuracy were tested on four additional subjects by comparing the mean N1 susceptibility and T2* obtained using the atlas to those obtained from manual ROIs and by measuring their geometrical proximity.