Diagnostic accuracy of MRI for neurodegenerative parkinsonism

The pathophysiology of Parkinson*s disease (PD) is characterized by an
extensive and progressive loss of dopaminergic neurons of the substantia nigra
(SN). Usually, it can be well diagnosed based on its clinical symptoms.
However, particularly in the early stages of the disease, not all symptoms
might be present and the diagnosis remains challenging. Recently, novel MRI
sequences have been developed to assess the SN. More specific, susceptibility
map weighted image (SMWI) is capable of visualizing nigrosome 1 and iron
deposition in the SN. These measures are altered in nigrostriatal
neurodegeneration and therefore have the potential to benefit the diagnostic
process in parkinsonian patients in which the diagnosis remains unclear.
Recently, an automated diagnostic algorithm that utilizes this MRI sequence
showed a high potential to support the diagnosis of Parkinson*s disease within
a small group of patients with a clear clinical diagnosis. It is clinically
relevant yet unclear, how this technique performs in patients with an uncertain
clinical diagnosis.
In recent years more promising diagnostic techniques for neurodegenerative
parkinsonism have been developed. MRI sequences such as neuromelanin sensitive
MRI (nmMRI), quantitative susceptibility mapping (QSM), diffusion tensor
imaging (DTI) and MR STAT are capable to assess differences in the SN between
patients with PD and healthy controls. In addition, recent research has shown a
difference in composition of sebum in patients with PD compared with healthy
controls. However, these novel techniques are not yet applied in medical
practice and diagnostic accuracy has to been further investigated.

The primary objective is to determine the diagnostic accuracy of the automated
diagnostic software (mPDia, Heuron) using SMWI to distinguish neurodegenerative
parkinsonism from patients with non-neurodegenerative parkinsonism compared
with the final diagnosis of a neurologist including the results of DAT SPECT
imaging. Secondary objectives are more exploratory to investigate the
diagnostic characteristics and accuracy of nmMRI, QSM, MR STAT, DTI, and
composition of sebum for neurodegenerative parkinsonism.

Combined retrospective and prospective diagnostic study.

The study does not provide a direct benefit for the participants. However, the
aim of this study is to assess the diagnostic accuracy of MRI for patients with
CUPS. MRI does not expose patients to radiation and is more widely available.
Hence, this study benefit patients with CUPS as a group. There is no known risk
of harm of the procedures of this study. Therefore, disadvantage of
participation is limited.