Characterization and diagnostic potential of R2* in early-stage progressive supranuclear palsy variants

Vincent Beliveau; Christoph Müller; Ruth Steiger; Elke R Gizewski; Werner Poewe; Klaus Seppi; Christoph Scherfler

doi:10.1016/j.parkreldis.2022.06.021

Characterization and diagnostic potential of R₂* in early-stage progressive supranuclear palsy variants

Parkinsonism Relat Disord. 2022 Aug:101:43-48. doi: 10.1016/j.parkreldis.2022.06.021. Epub 2022 Jun 30.

Authors

Vincent Beliveau¹, Christoph Müller², Ruth Steiger³, Elke R Gizewski³, Werner Poewe², Klaus Seppi¹, Christoph Scherfler⁴

Affiliations

¹ Medical University of Innsbruck, Department of Neurology, Innsbruck, Austria; Medical University of Innsbruck, Neuroimaging Research Core Facility, Innsbruck, Austria.
² Medical University of Innsbruck, Department of Neurology, Innsbruck, Austria.
³ Medical University of Innsbruck, Neuroimaging Research Core Facility, Innsbruck, Austria; Medical University of Innsbruck, Department of Neuroradiology, Innsbruck, Austria.
⁴ Medical University of Innsbruck, Department of Neurology, Innsbruck, Austria; Medical University of Innsbruck, Neuroimaging Research Core Facility, Innsbruck, Austria. Electronic address: christoph.scherfler@i-med.ac.at.

PMID: 35792337
DOI: 10.1016/j.parkreldis.2022.06.021

Abstract

Introduction: Iron accumulation in subcortical brain nuclei has been shown to be differentially increased in atypical parkinsonian disorders. It is unclear whether the patterns of iron accumulation are consistent between variants of progressive supranuclear palsy (PSP) and their diagnostic utility in early to moderately advanced stages of the diseases.

Methods: Brain iron content (R₂*) was quantified using magnetic resonance imaging in patients clinically diagnosed as PSP - parkinsonism (PSP-P, n = 15), PSP - Richardson's syndrome (PSP-RS, n = 14), Parkinson's disease (PD, n = 15), or the parkinsonian variant of multiple system atrophy (MSA-P, n = 14) using established criteria, and healthy controls (HC). Disease duration was less than 5 years in all patients. The quantification of regional R₂* was performed using a semi-automatized approach.

Results: Significant group differences in R₂*, primarily within the red nucleus and the substantia nigra, were identified between PSP, PD, MSA-P, and HC, but not between PSP-P and PSP-RS. However, distinct R₂* correlation patterns across brain regions were observed for the different groups. Good classification performances (sensitivity and specificity >80%) were only obtained for PSP vs. HC. For all other comparisons, sensitivity and/or specificity was below <70%.

Conclusion: Iron accumulation in subcortical brain nuclei has distinct correlated patterns in PSP-P and PSP-RS, which could be reflecting different pathophysiological mechanisms. Increased iron content in these nuclei appears to be a predictor for atypical parkinsonian disorders such as PSP and MSA. Further studies are required to reproduce this finding and elucidate the evolution of these patterns over the course of the disease.

Keywords: Brain iron; Convolutional neural network; Diagnostic marker; Progressive supranuclear palsy; R2*.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Iron
Magnetic Resonance Imaging / methods
Multiple System Atrophy* / diagnostic imaging
Multiple System Atrophy* / pathology
Parkinson Disease* / diagnostic imaging
Parkinson Disease* / pathology
Parkinsonian Disorders* / diagnostic imaging
Parkinsonian Disorders* / pathology
Supranuclear Palsy, Progressive* / diagnosis

Substances

Iron