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Published in: Journal of Neurology 10/2023

Open Access 17-06-2023 | Polyneuropathy | Original Communication

Magnetic resonance neurography and diffusion tensor imaging of the sciatic nerve in hereditary transthyretin amyloidosis polyneuropathy

Authors: Roberto Gasparotti, Alessandro Salvalaggio, Daniele Corbo, Giorgio Agazzi, Mario Cacciavillani, Alessandro Lozza, Silvia Fenu, Grazia De Vigili, Matteo Tagliapietra, Gian Maria Fabrizi, Davide Pareyson, Laura Obici, Chiara Briani

Published in: Journal of Neurology | Issue 10/2023

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Abstract

The therapeutic advance in hereditary transthyretin amyloidosis (ATTRv amyloidosis) requires quantitative biomarkers of nerve involvement in order to foster early diagnosis and monitor therapy response. We aimed at quantitatively assessing Magnetic Resonance Neurography (MRN) and Diffusion Tensor Imaging (DTI) properties of the sciatic nerve in subjects with ATTRv-amyloidosis-polyneuropathy (ATTRv-PN) and pre-symptomatic carriers (ATTRv-C). Twenty subjects with pathogenic variants of the TTR gene (mean age 62.20 ± 12.04 years), 13 ATTRv-PN, and 7 ATTRv-C were evaluated and compared with 20 healthy subjects (mean age 60.1 ± 8.27 years). MRN and DTI sequences were performed at the right thigh from the gluteal region to the popliteal fossa. Cross-sectional-area (CSA), normalized signal intensity (NSI), and DTI metrics, including fractional anisotropy (FA), mean (MD), axial (AD), and radial diffusivity (RD) of the right sciatic nerve were measured. Increased CSA, NSI, RD, and reduced FA of sciatic nerve differentiated ATTRv-PN from ATTRv-C and healthy subjects at all levels (p < 0.01). NSI differentiated ATTRv-C from controls at all levels (p < 0.05), RD at proximal and mid-thigh (1.04 ± 0.1 vs 0.86 ± 0.11 p < 0.01), FA at mid-thigh (0.51 ± 0.02 vs 0.58 ± 0.04 p < 0.01). According to receiver operating characteristic (ROC) curve analysis, cutoff values differentiating ATTRv-C from controls (and therefore identifying subclinical sciatic involvement) were defined for FA, RD, and NSI. Significant correlations between MRI measures, clinical involvement and neurophysiology were found. In conclusion, the combination of quantitative MRN and DTI of the sciatic nerve can reliably differentiate ATTRv-PN, ATTRv-C, and healthy controls. More important, MRN and DTI were able to non-invasively identify early subclinical microstructural changes in pre-symptomatic carriers, thus representing a potential tool for early diagnosis and disease monitoring.
Literature
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Metadata
Title
Magnetic resonance neurography and diffusion tensor imaging of the sciatic nerve in hereditary transthyretin amyloidosis polyneuropathy
Authors
Roberto Gasparotti
Alessandro Salvalaggio
Daniele Corbo
Giorgio Agazzi
Mario Cacciavillani
Alessandro Lozza
Silvia Fenu
Grazia De Vigili
Matteo Tagliapietra
Gian Maria Fabrizi
Davide Pareyson
Laura Obici
Chiara Briani
Publication date
17-06-2023
Publisher
Springer Berlin Heidelberg
Published in
Journal of Neurology / Issue 10/2023
Print ISSN: 0340-5354
Electronic ISSN: 1432-1459
DOI
https://doi.org/10.1007/s00415-023-11813-z

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