Getting the right diagnosis for Parkinson's disease and similar movement disorders can be tricky, especially early on. But a new analysis of existing research suggests a specialized MRI technique might help doctors tell them apart.
The technique, called quantitative susceptibility mapping (QSM), measures iron levels in different parts of the brain. The study pooled data from 1,218 people, including 626 with Parkinson's disease, 160 with multiple system atrophy (MSA), 176 with progressive supranuclear palsy (PSP), and 256 healthy controls. It found that each condition had a unique pattern of iron buildup.
For example, people with Parkinson's had more iron in the substantia nigra (a key brain area for movement) compared to those with MSA or PSP. Those with MSA showed increased iron in the putamen, while PSP patients had higher iron in the red nucleus. The test was fairly accurate at distinguishing MSA from other conditions (AUC 0.83) and even better at identifying PSP (AUC 0.89).
But there are important caveats. The studies used different MRI machines and settings, which could affect results. Also, some findings might be influenced by small-study effects. This is an observational analysis, so it can't prove cause and effect. More work is needed to standardize the technique before it can be used in clinics.