Multimodal MRI of the brain’s visual system can catch Parkinson’s early on

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 - ParkinsonsMRI
Left and right optic radiation image in a representative subject overlaid onto a T1-weighted axial volume image of the same subject. (University Vita-Salute San Raffaele via Radiology journal)

Early-stage Parkinson’s disease shows up on MRI in parts of the brain connected to the eyes, which may help clinicians confirm the diagnosis, follow the disease’s progression and monitor the patient’s response to drug treatments, according to a small Italian study published online July 11 in RSNA’s Radiology.

Led by Alessandro Arrigo, MD, an ophthalmology resident at University Vita-Salute San Raffaele in Milan, the research team recruited 20 patients newly diagnosed with Parkinson’s and 20 control subjects matched by age.

They imaged each with T1-weighted and diffusion-weighted MRI, assessing the status of visual-system white matter, gray matter and the optic chiasm, which is the X-shaped region where the optic nerves partially cross.

In the patients with Parkinson disease, the researchers found significant changes in the connectivity and diffusivity of optic radiation.

Other findings on MRI included significant reductions in visual cortical volumes and in chiasmatic area and volume.

Arrigo et al. conclude that visual-system alterations can be detected in early stages of Parkinson disease and that the entire intracranial visual system may be involved.

They suggest their multimodal structural MR imaging approach could be used for longitudinal studies “to help understand the progression of visual alterations in the course of the disease and to assess positive or negative effects of pharmacologic treatments on visual structures.

“Moreover, our results suggest that the involvement of the visual system could be considered as a marker of Parkinson’s disease along with other nonmotor symptoms that may occur even before the onset of motor symptoms.”

RSNA has posted the full study for free.