Related Experiment Video
Updated: Aug 19, 2026
Lesion Explorer: A Video-guided, Standardized Protocol for Accurate and Reliable MRI-derived Volumetrics in Alzheimer's Disease and Normal Elderly
Published on: April 14, 2014
Sequential postoperative appearance of radiofrequency pallidotomy lesions on MRI
1Division of Neurosurgery, University of California at Los Angeles, School of Medicine, USA.
Abstract:
We analyzed 10 radiofrequency (RF) lesions over time in 9 patients who had follow-up MRI 1 h to 43 weeks following stereotactic pallidotomies performed for medically intractable idiopathic Parkinson's disease. Pallidotomies were performed under MRI guidance, microelectrode recording, and electrical stimulation with neurological monitoring. We compared the MRI taken within 1 h after surgery for each patient to their respective follow-up MRI to determine the changes in size and signal characteristics of RF lesions over time. The postoperative follow-up MRI of RF lesions roughly fell into 4 time periods: 1 h (n = 10), 2 months (n = 3), 6 months (n = 3), and 10 months (n = 4). The average volume (+/- SD, mm3) of these lesions at each phase were as follows: 1 h = 124.35 +/- 58.48; 2 months = 50.5 +/- 30.71; 6 months = 32.36 +/- 21.07; 10 months = 53.19 +/- 28.91. The steep decline in the size of the lesion stabilizes by the 2-month period. Thereafter, the lesion size at 6 and 10 months remains stable. Eventually, the center of coagulative necrosis completely disappears, and the lesions persists as a cystic cavity. The contrast uptake of these RF lesions appears to resolve by the 6-month period. Immediate postoperative images show strong enhancement with gadolinium. There is a lesser degree of enhancement at 2 months, and no appreciable enhancement by 6 months. Interestingly, the patients with better outcome tended to have larger RF lesions. However, this difference was not statistically significant.
Insights
Radiofrequency (RF) lesions created during stereotactic pallidotomies for Parkinson's disease shrink significantly within two months. These lesions stabilize in size and lose contrast enhancement by six months, eventually becoming cystic cavities.
Area of Science:
- Neurosurgery
- Radiology
- Neurology
Background:
- Stereotactic pallidotomy is a neurosurgical procedure used for medically intractable idiopathic Parkinson's disease.
- Radiofrequency (RF) lesions are created during this procedure to ablate target brain tissue.
- Understanding the evolution of these lesions is crucial for assessing treatment outcomes.
Purpose of the Study:
- To analyze the changes in size and signal characteristics of RF lesions over time after stereotactic pallidotomy.
- To correlate lesion changes with patient outcomes.
Main Methods:
- Analysis of 10 RF lesions in 9 patients with Parkinson's disease.
- Serial MRI scans were performed at 1 hour, 2 months, 6 months, and 10 months post-surgery.
- Comparison of immediate postoperative MRI with follow-up scans to track lesion evolution.
Main Results:
- Average lesion volume decreased from 124.35 mm³ at 1 hour to 50.5 mm³ at 2 months, stabilizing thereafter.
- Lesion size stabilized by the 2-month follow-up, with the center of necrosis disappearing and lesions becoming cystic.
- Contrast enhancement resolved by 6 months post-surgery; immediate scans showed strong enhancement, decreasing by 2 months.
Conclusions:
- RF lesions undergo significant shrinkage and signal changes in the months following stereotactic pallidotomy.
- Lesion size and contrast enhancement patterns evolve predictably over time.
- While larger lesions trended with better outcomes, this association was not statistically significant.
