February 1, 2026

@michaelokun

MRI assessment of the nigrosome in Parkinson’s disease: Is it ready for everyday clinical practice? Spoiler alert: It is not ready for prime time. What is a nigrosome? A nigrosome is a small cluster of dopamine producing nerve cells in the substantia nigra that can sometimes be seen on special MRI sequences and it is frequently lost in Parkinson’s disease. Yanzi and colleagues describe in a new paper that just dropped in Movement Disorders Clinical Practice how well the nigrosome assessment on routine MRI works in real world clinical practice. They looked at its use by movement disorder related health care providers. Key Points: - Nigrosome assessment on routine 3T MRI showed moderate sensitivity, but relatively low specificity when distinguishing Parkinson’s disease from essential tremor. - Performance did not differ meaningfully between trained and untrained raters, suggesting brief instruction alone was not enough. - Specificity and overall accuracy improved w/ experience, pointing to a possible learning effect over time. My take: This paper brings some ‘realism’ to the nigrosome conversation. What works well in expert hands w/ optimized MRI protocols does not automatically translate into everyday clinical practice. Imaging biomarkers must perform reliably across settings, scanners and readers if they are to help folks in routine care. Here are 5 points that resonated w/ me: 1- Clinical diagnosis still matters most, and MRI signs should support, not replace, careful bedside evaluation. 2- Nigrosome imaging is sensitive, however false positives limit its standalone value in day to day practice. 3- Experience improves accuracy, suggesting repetition and feedback may matter more than short training sessions. 4- MRI protocol details such as slice thickness and sequence choice likely drive much of the variability. 5- For now, nigrosome assessment may be a helpful adjunct in select cases, however it is not yet ready as a routine diagnostic tool for all folks w/ tremor. https://movementdisorders.onlinelibrary.wiley.com/doi/10.1002/mdc3.70530 #michaelokun #fixelinstitute #parkinson #neuroradiology