Fast susceptibility-weighted imaging using echo planar imaging at 1.5 T for swallow tail sign biomarker detection in Parkinson's disease

Abstract

Introduction

This study evaluated the feasibility and diagnostic accuracy of a fast-imaging technique combining Echo Planar Imaging (EPI) and Susceptibility-Weighted Imaging (SWI) at 1.5 T for visualizing the Swallow Tail Sign (STS) in Parkinson's Disease (PD). The STS, a biomarker linked to PD pathogenesis, offers promise for non-invasive diagnosis. However, conventional SWI often requires high field strengths and lengthy scan times, limiting accessibility. This study aimed to provide a faster, more practical alternative for PD diagnosis.

Methods

A prospective study included 130 participants (22 early-stage PD, 108 healthy controls [HC]) recruited consecutively from a neurology clinic. Eligibility required freedom from MRI contraindications. A fast EPI-SWI sequence was employed as the primary diagnostic tool, with Movement Disorder Society criteria serving as the reference standard. Diagnostic measures, including sensitivity, specificity, predictive values, and the area under the ROC curve (AUC), were calculated.

Results

After excluding participants with motion artifacts or suboptimal image quality, 120 participants (20 PD, 100 HC) were included in the analysis. The fast EPI-SWI technique demonstrated 100 % sensitivity, 96 % specificity, a positive predictive value (PPV) of 83.3 %, and a negative predictive value (NPV) of 100 %. The AUC for diagnostic accuracy was 0.98.

Conclusion

The fast EPI-SWI sequence at 1.5 T achieved high diagnostic accuracy for detecting the STS, offering a practical solution for early PD diagnosis in settings with limited access to high-field MRI.

Implications for practice

The use of EPI SWI for detecting the Swallow Tail Sign could provide a faster and more accessible method for early diagnosis of Parkinson's disease in clinical settings, particularly in resource-limited environments.