Quantitative Assessment of Visible Nigrosome‐1 in Patients with Parkinson's Disease

BACKGROUND: The nigrosome-1 (N1) sign on susceptibility-weighted imaging (SWI) typically disappears in Parkinson's disease (PD), though some patients can show uni-/bilaterally preserved N1. OBJECTIVE: Investigating whether visible nigrosomes in PD patients differ from those of healthy subjects (HC). METHODS: Forty-eight PD and 35 HC underwent 3 T-MR-SWI. The N1 was visually assessed, and visible N1 were segmented to calculate volume, area and susceptibility values. These metrics were investigated for distinguishing between visible nigrosomes-1 of PD patients and HC. RESULTS: Among PD patients, 16 had bilateral N1 loss and 32 had unilaterally (n = 27) or bilaterally (n = 5) preserved N1. The visible N1 were significantly smaller in PD than in HC (P < 0.001), while having similar susceptibility values (P = 0.251). N1 area and volume showed high performance (AUC: 0.97-0.98) in distinguishing PD from HC. CONCLUSION: The measurement of volume and area of N1 region may complement visual assessment on SWI to optimize diagnostic performance in PD.