Chemical Exchange Saturation Transfer MRI Signal Loss of the Substantia Nigra as an Imaging Biomarker to Evaluate the Diagnosis and Severity of Parkinson's Disease.

Chunmei Li,Wen Su,Jintao Zhang,Min Chen,Haibo Chen,Shuhua Li,Rui Wang,Baohui Lou,Guodong Song,Xuna Zhao,Jinyuan Zhou,Shuai Zhang

doi:10.3389/fnins.2017.00489

Abstract

The early diagnosis of Parkinson's disease (PD) and the accurate evaluation of disease severity are crucial for intervention and treatment in PD patients. In this study, we applied chemical exchange saturation transfer (CEST) imaging to patients at different stages of PD and explored the clinical value of the CEST signal loss of the substantia nigra as an imaging biomarker of PD. The measured CEST signal intensities (including amide proton transfer-weighted or APTw, and total CEST or CESTtotal) of the substantia nigra in PD patients showed a significantly decreased tendency with PD progression. Compared to normal controls, the APTw and CESTtotal intensities of PD patients significantly decreased at both the early and advanced or late stages. These APTw and CESTtotal values of the substantia nigra were also significantly lower in advanced or late stage PD patients than in early stage PD patients. For PD patients with unilateral symptoms, the APTw and CESTtotal values in the substantia nigra on the affected side were significantly lower than those in normal controls. Both the APTw and CESTtotal values of PD were significantly correlated with the severity of disease and disease duration. Our findings suggest that the CEST MRI signal of the substantia nigra is a potential imaging biomarker for the diagnosis and monitoring of the severity of PD.

Highlights

Parkinson’s disease (PD) is a common progressive neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (Fearnley and Lees, 1991)
We investigated the potential of chemical exchange saturation transfer (CEST)/amide proton transfer (APT) imaging for the diagnosis of PD and the evaluation of disease severity
Our present results revealed the efficiency of CEST/APT signal intensities in the detection of PD, even at the early stage of the disease

Summary

Introduction

Parkinson’s disease (PD) is a common progressive neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (Fearnley and Lees, 1991). The diagnosis of PD is mainly based on the clinical manifestations. The accuracy of the diagnosis is often unsatisfactory, even for experienced movement-disorder specialists (Hughes et al, 1992; Tolosa et al, 2006). The situation is even worse for patients at the early stage of PD, when the clinical manifestations can be atypical. The early detection of PD would make early intervention possible, which may greatly improve the prognosis for PD patients. In addition to the diagnosis, monitoring disease severity, which plays an important role in disease-modifying

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