Quantitative Analysis Versus Visual Assessment of Neuromelanin MR Imaging for the Diagnosis of Parkinson’s disease

Background: Specific MR sequences have been able to identify the loss of neuromelanin in the substantia nigra (SN) of early stage Parkinson's disease (PD) patients. Since this technique may have a significant impact in clinical patient management, easy and widely available imaging analysis is needed for routine use. Objective: In this study we compared a quantitative analysis with a visual assessment of SN neuromelanin-sensitive MR images in early stage PD patients, in terms of pattern changes recognition and diagnostic accuracy. Methods: The inclusion criteria were untreated "de novo" PD patients or a 2-5 year PD duration; in addition, age matched controls were enrolled. These were studied with a high-resolution T1-weighted MR imaging sequence at 3.0 Tesla to visualize neuromelanin. The primary outcome was the comparison of quantitative width measurement with visual assessment by experienced neuroradiologists of SN neuromelanin sensitive MR images for PD diagnosis. Results: A total of 12 "de novo" PD patients, 10 PD patients with 2-5 year disease duration and 10 healthy controls were evaluated. We obtained a good accuracy in discriminating early-stage PD patients from controls using either a quantitative width measurement of the T1 high signal or a simple visual image inspection of the SN region. Conclusions: Visual inspection of neuromelanin-sensitive MR images by experienced neuroradiologists provides comparable results to quantitative width measurement in the detection of early stage PD SN changes and may become a useful tool in clinical practice.