From the Guidelines
Parkinson's patients should typically get an MRI as part of their diagnostic workup, as it is the optimal imaging modality for evaluating Parkinsonian syndrome due to its soft-tissue characterization and sensitivity to iron deposition. According to the American College of Radiology 1, MRI of the brain without IV contrast is preferred because it can demonstrate increased susceptibility in the substantia nigra and thinning of the pars compacta with deposition. The use of advanced MRI, such as 7-T MRI, may offer more meaningful and earlier diagnostic opportunities for patients with suspected Parkinson's disease (PD) and other Parkinsonian syndromes 1.
Some key benefits of MRI in Parkinson's patients include:
- Soft-tissue characterization
- Sensitivity to iron deposition
- Ability to demonstrate increased susceptibility in the substantia nigra
- Ability to show thinning of the pars compacta with deposition
- Potential to identify the "eye-of-the-tiger sign," a focus of T2 hyperintensity within the anteromedial aspect of the otherwise T2 hypointense globus pallidus
While an MRI cannot definitively diagnose Parkinson's disease itself, as the diagnosis remains primarily clinical, it serves as a valuable tool to exclude alternative explanations for symptoms, such as strokes, tumors, hydrocephalus, or other neurodegenerative disorders 1. Therefore, an MRI is a crucial diagnostic tool for Parkinson's patients, particularly those with atypical features, rapid progression, poor response to medication, or onset at a young age.
From the Research
MRI for Parkinson's Patients
- MRI can aid in improving the accuracy and confidence of a Parkinson's disease diagnosis, especially in early disease courses 2
- The main purpose of brain MRI is to assess cerebrovascular damage and exclude other possible causes of parkinsonism, such as normal pressure hydrocephalus 2
- MRI can support the diagnosis of a specific form of atypical parkinsonism and differentiate it from Parkinson's disease 2, 3, 4
Diagnostic Value of MRI
- MRI has enhanced the diagnostic accuracy in the differential diagnosis of neurodegenerative parkinsonism over the last three decades 3
- Advanced MRI sequences and modern image analysis algorithms can aid in the diagnosis of early, new onset, and even prodromal Parkinson's disease 3
- Multimodal MRI has significantly improved diagnostic accuracy and understanding of the pathophysiology of Parkinsonian disorders 4
MRI Signs of Parkinson's Disease
- High-field MRI and new optimized MRI sequences can define specific MRI signs of Parkinson's disease, enabling differentiated structural image interpretation and consecutive diagnostic workup 5
- Cerebral alterations can be detected in prodromal stages of Parkinson's disease using MRI 5
- The combination of specific MRI signs makes it possible to differentiate between Parkinson's disease and atypical parkinsonism 5
Clinical Application of MRI
- Conventional MRI is a well-established method for the exclusion of symptomatic parkinsonism due to other pathologies such as tumors, cerebral ischemia, or inflammatory diseases 6
- Advanced MRI techniques, such as magnetic resonance volumetry, diffusion-weighted imaging, magnetization transfer imaging, and proton magnetic resonance spectroscopy, can quantitatively illustrate abnormalities in the basal ganglia and infratentorial structures in atypical parkinsonian disorders 6