Nigrosome Imaging and Neuromelanin Sensitive MRI in Diagnostic Evaluation of Parkinsonism

Abstract

Background Recent developments in magnetic resonance imaging (MRI) techniques have offered new research opportunities to visualize in vivo substantia nigra pathology in Parkinson's disease (PD). This paper summarizes the main findings of nigrosome imaging and neuromelanin sensitive MRI studies in patients with PD and other parkinsonisms. Methods The PubMed database was searched from 2005 to 2017 using the following keywords: Parkinson's disease and parkinsonism, in combination with MRI, nigrosome, neuromelanin, and iron. Only publications in English were included. Results Nigrosome or dorsal nigral hyperintensity abnormalities are studied using T2* and susceptibility weighted imaging MRI sequences in most studies, whereas Neuromelanin imaging is usually performed using T1‐weighted fast spin echo sequence. Nigrosome abnormalities have been consistently demonstrated in PD patients, and nigrosome imaging has high sensitivity and specificity in distinguishing PD from healthy controls, though it is unable to reliably separate PD from atypical parkinsonisms. Reduced neuromelanin‐related signals and/or volume loss in neuromelanin containing structures have been found in PD patients, and neuromelanin sensitive MRI imaging can also discriminate PD patients from healthy controls with high accuracy, though there is a degree of heterogeneity in the imaging findings. Preliminary findings suggested that longitudinal change of neuromelanin signal could be detected in PD, raising the possibility of using it as a marker of disease progression. Conclusion Nigrosome imaging and neuromelanin sensitive MRI are promising tools to study nigral pathology and to improve the diagnosis of PD. However, further studies are required to standardize analysis approaches, confirm longitudinal changes, and assess their generalizability.

Modern Brainstem MRI Techniques for the Diagnosis of Parkinson's Disease and Parkinsonisms

“…Studies have confirmed that patients with PD have a significantly reduced NM signal in the SN and LC ( 20 , 37 , 37 , 39 – 41 ). These signal changes have been found to be correlated with the absorption values of the nigrostriatal dopamine transporter ( 42 ).…”

Parkinson’s Disease: Available Clinical and Promising Omics Tests for Diagnostics, Disease Risk Assessment, and Pharmacotherapy Personalization

“…Thus, the technique of MRI visualization of nigrosome-1 allows differentiating PD patients from health subjects even at the onset of the disease. However, some cases of atypical parkinsonism (MSA, PSP, and CBD) may be characterized by a similar pattern of the disappearance of the nigrosome-1 to PD [57][58][59].…”

“…Used for differentiating PD patients from healthy subjects, but not able to differentiate from some cases of atypical parkinsonism (MSA, PSP, and CBD) [51][52][53][54][55][56][57][58][59][60][61][62].…”

Dopamine transporter imaging in neurodegenerative movement disorders: PET vs. SPECT

“…Martín-Bastida et al [34] found neuromelanin to correlate with disease duration and DAT with UPDRS motor score, concluding neuromelanin might reflect the underlying pathophysiological process, whereas DAT represents the functional state of the dopaminergic system [48]. Nigrosome imaging [49,50] using T2* and susceptibility weighted imaging MRI sequences could be another SN MR-biomarker of interest to combine with DAT imaging. Further validation of the appropriate reference tissue and attenuation correction methods for DAT imaging with the new PET-MRI systems, however, is needed [38,[51][52][53].…”