Objective: In contrast to their 1.5T counterparts, high field MRI scanners are often unavailable in clinical routine, particularly in primary care facilities and underserved regions. The present study compared the diagnostic performance 1.5 and 3 Tesla (T) MRI regarding the identification of loss of dorsolateral nigral hyperintensity (DNH) in patients with neurodegenerative parkinsonism and healthy controls (HC).

Background: Absent DNH on susceptibility weighted imaging (SWI) sequences on high or ultra-high field MRI (3T or more) is a common finding in patients with neurodegenerative parkinsonism.

Method: The presence of DNH was visually assessed in a blinded fashion in a case-control study involving 86 patients with neurodegenerative parkinsonism and 33 HC who underwent both 1.5T and 3T MRI. Axial SWI 3D sequences were similar at both scanners with a slice thickness of 2.4 mm.

Results: Overall, SWI scans were analyzable in 93 of 119 study participants. DNH was absent unilaterally in all patients with MSA or PSP and most of the patients with PD at 1.5T and 3T, resulting in a sensitivity of 97% and 96%, respectively. While it was absent in one of the HC at 3T, it was absent in 77% of the HC at 1.5T resulting in an insufficient specificity (i.e. 23%) at 1.5T.

Conclusion: While visual assessment of DNH on high field SWI sequences provides a useful diagnostic imaging marker for neurodegenerative parkinsonism, its diagnostic value at 1.5T MRI is limited by poor specificity.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dorsolateral-nigral-hyperintensity-on-1-5-versus-3t-susceptibility-weighted-magnetic-resonance-imaging-in-neurodegenerative-parkinsonism/