An advanced, noninvasive MRI technique in patients with Parkinson disease and essential tremor was found to potentially lead to better outcomes without surgery and lessen risk of adverse effects, according to study findings published this week.
An advanced, noninvasive MRI technique in patients with Parkinson disease and essential tremor was found to potentially lead to better outcomes without surgery and lessen risk of adverse effects, according to study findings published this week in Brain.
The MRI method, which serves as a magnetic resonance—guided, high-intensity, focused ultrasound, allows neuroradiologists to precisely target pea-sized regions in the brain’s thalamus, which is involved with movement and linked with Parkinson disease and essential tremor. The noninvasive, image-guided procedure burns away, or ablates, the damaged intracranial tissue contributing to the progression of these diseases.
Although this procedure is approved by the FDA, researchers highlight that the current landmark-based targeting techniques have limitations.
“A significant limitation of standard MRI sequences is that the ventral intermediate nucleus, dentatorubrothalamic tract, and other deep brain nuclei cannot be clearly identified,” said the study authors.
Lead study author Bhavya R. Shah, MD, assistant professor of radiology and neurological surgery at UT Southwestern's Peter O'Donnell Jr. Brain Institute, highlighted the adverse impact that imprecise targeting could have on patients as it can cause problems in walking and speaking, with 15% to 20% of those having these effects permanently.
The researchers sought to demonstrate the efficacy of emerging imaging techniques that could be used by neuroradiologists, such as fast grey matter acquisition T1 inversion recovery, quantitative susceptibility mapping (QSM) and susceptibility weighted imaging, and diffusion tensor imaging tractography. They also compared these novel MRI techniques to current targeting techniques.
According to study findings, refined fast grey matter acquisition T1 inversion recovery, diffusion tractography, and QSM were all found to be better at categorizing the target tissue. Shah noted diffusion tractography as possibly the most promising imaging method, which creates precise brain images by accounting for the natural water movement within tissues.
"The benefit for patients is that we will be better able to target the brain structures that we want," said Shah. "And because we're not hitting the wrong target, we'll have fewer adverse effects."
Shah concluded by saying his team plans to collaborate with Mayo Clinic to further test the diffusion tractography method in a multicenter clinical trial.
Shah BR, Lehman VT, Kaufmann TJ, et al. Advanced MRI techniques for transcranial high intensity focused ultrasound targeting. Brain. Published online June 15, 2020. doi:10.1093/brain/awaa107