Imaging the Nigrosome 1 in the substantia nigra using susceptibility weighted imaging and quantitative susceptibility mapping: An application to Parkinson's disease

Abstract

HighlightsTo date, there is no standard MR imaging protocol to characterize the nigrosome1 territory of the substantia nigra.Nigrosome 1 can be consistently visualized using true SWI with a resolution of at least 0.67 × 0.67 × 1.34 mm3.Loss of nigrosome 1 on true SWI can differentiate Parkinsonism from healthy controls.Not all 'Parkinson's disease patients show bilateral loss of nigrosome 1.

Increased iron-deposition in lateral-ventral substantia nigra pars compacta: A promising neuroimaging marker for Parkinson's disease

“…Nigrosome-1 can be seen as a hyperintense region embedded in the hypointense SN in T 2 - or T 2 *-weighted images of control subjects ( Blazejewska et al, 2013 ). PD-related iron deposition, associated with neuronal loss, causes a reduction in T 2 - or T 2 *-weighted signal in nigrosome-1 and the marker is not present in PD subjects ( Blazejewska et al, 2013 , Cheng et al, 2020 , Schwarz et al, 2018 ). Intriguingly, nigrosome-1 is located in the lateral and ventral regions of the neuromelanin-defined SNpc ( Huddleston et al, 2018 ) and iron deposition in the lateral-ventral tier of SNpc observed in this work may be imaging similar aspects of PD-pathology.…”

Susceptibility‐Weighted 3T MRI of the Swallow Tail Sign in Multiple Sclerosis: A Case Control Study

“…Furthermore, the in-plane voxel dimensions of the axial SWI used in our study were larger compared to the recommended dimensions. 13 Therefore, the interpretation of our results should be done cautiously. In line with previous studies, 1,2 we found an abnormal swallow tail sign in 17% of control patients, a finding that has been attributed to limited spatial resolution and lower signal-to-noise and contrast-to-noise ratios that are achievable at 3T MRI systems in reasonable scan time.…”

The clinical application of nigrosome 1 detection on high-resolution susceptibility-weighted imaging in the evaluation of suspected Parkinsonism: The real-world performance and pitfalls

“…Based on a previous study regarding normal NG1 on 7T MRI [3], NG1 was evaluated from the level of the inferior colliculi to the red nucleus of midbrain. Asymmetry of NG1 [22] and abnormal shape of the hypersignal intensity varying from the typical oval, linear to loop, cluster, and strip have been reported [12]. Therefore, regardless of the shape, the hypersignal intensity, which was noted in the dorsolateral aspect of substantia nigra, was described as normal NG1.…”

“…However, technically, imaging parameters and protocols for NG1 detection are not standardized [1]. By the definition of the term "high resolution", recent studies suggest a minimum spatial resolution of 0.5 x 0.5 x 1.0mm or 0.67 x 0.67 x 1.34 mm to evaluate NG1 on susceptibility weighted images including SWI or QSM [1,12]. In terms of image contrast, according to Kim et al, the use of susceptibility map-weighted imaging (SMWI) allows for quantitative assessment and enhances the diagnostic performance by increasing the contrast-to-noise ratio (CNR) [1,13].…”