Inter & Intra Rater Agreement In Assessment Of Nigrosome-1 Hyperintensity on weighted imaging

Absence of Nigrosome-1(N1) hyperintensity on SWI-MRI is a relatively new sign in Parkinson’s disease (PD) with a high diagnostic accuracy on 3T MRI . ➤ Pathology in PD starts in substructures in the dorsolateral substantial nigra (SN) called Nigrosomes, with N1 representing the largest cluster of dopaminergic cells in the pars compacta (SNpc). ➤ N1 appears as an ovoid hyperintensity in the SNpc ventralis, bounded medially by SNpc dorsalis, anteriorly & laterally by SN pars reticulata (SNpr), resembling a Swallow tail. Loss of the hyperintensity reflects loss of SN dopaminergic neurones Aims ➤To assess the feasibility of N-1 detection on departmental 1.5T and 3T SWI-MRI. ➤To measure the inter- and intra-rater agreement, and to compare the values with the literature