The evaluation of the swallow tail sign in patients with parkinsonism and gait disorders.

Abstract

BACKGROUND:

Swallow tail sign (STS), which represents nigrosome-1 in the substantia nigra on 3 Tesla (T) susceptibility-weighted imaging (SWI), has attracted attention as a promising magnetic resonance imaging (MRI) biomarker for idiopathic Parkinson's disease (iPD). Some reports have shown high sensitivity and specificity-both above 94%-for distinguishing iPD from healthy controls. However, abnormal STS has been observed in many neurodegenerative parkinsonisms and even in multiple sclerosis.

METHODS:

All patients with parkinsonism who had 3 T MRI were included in a retrospective chart review from a single movement disorders clinic. All subjects were evaluated by a single movement disorder specialist, using Movement Disorders Society diagnostic criteria and American Academy of Neurology consensus guidelines for diagnoses. All MRIs were interpreted by a single neuroradiologist who was blinded to the diagnosis.

RESULTS:

Twenty patients were included in the study. Twelve had abnormal STS: iPD (n = 2), probable multiple system atrophy (n = 3), vascular parkinsonism (n = 1), psychogenic gait disorder (n = 1), neuroleptic parkinsonism (n = 2), cervical dystonia (n = 1), static encephalopathy (n = 1) and gait disorder of unknown etiology (n = 1). Eight had normal STS: iPD (n = 1), probable progressive supranuclear palsy (n = 1), vascular parkinsonism (n = 2), transient parkinsonism of unknown etiology (n = 2), valproic acid induced parkinsonism (n = 1), and essential tremor with parkinsonism (n = 1). 123I-Ioflupane SPECT dopamine transporter (DaT) scan results were available on seven subjects; four subjects had incongruency between DaT and MRI.

CONCLUSION:

Our results suggest that the abnormal STS is not, in isolation, a reliable biomarker of idiopathic Parkinson's disease.

• Authors: Duk Soo Kim, Glenn A Tung, Umer Akbar, Joseph H Friedman
• Journal: Journal of the neurological sciences (J Neurol Sci) Vol. 428 Pg. 117581 (09 15 2021) ISSN: 1878-5883 [Electronic] Netherlands
• PMID: 34333378 (Publication Type: Journal Article)
• Copyright: Copyright © 2021. Published by Elsevier B.V.

Topics

• Gait
• Humans
• Magnetic Resonance Imaging
• Parkinson Disease (complications, diagnostic imaging)
• Parkinsonian Disorders (complications, diagnostic imaging)
• Retrospective Studies
• Substantia Nigra