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Published on: April 14, 2014
Tract identification by novel MRI signal changes following stereotactic anterior capsulotomy
T A Hurwitz1, T Mandat, B Forster
1Department of Psychiatry, University of British Columbia, Vancouver, Canada. t.hurwitz@ubc.ca
Background:
Five patients underwent magnetic resonance imaging (MRI) following MRI-guided stereotactic bilateral anterior capsulotomy to detect lesion-related anatomic changes.
Methods:
Five disabled and treatment-resistant patients with major depression (n = 4) and obsessive-compulsive disorder (n = 1) underwent stereotactic bilateral anterior capsulotomy. All patients had postoperative MRI at 2 months and at 1-4 years after surgery. An additional patient who had a pure motor deficit following a spontaneous basal ganglia hemorrhagic stroke was imaged as a comparator.
Results:
The 2-month postcapsulotomy MRI showed a previously undescribed increase in T1-weighted signal within similar neural pathways for each patient. These pathways showed no changes in T2-weighted or fluid-attenuated inversion recovery sequences. The signal changes are different from the expected changes associated with anterograde Wallerian degeneration and identify retrograde changes in the proximal segment of the interrupted axon.
Conclusion:
Previously undescribed T1-weighted signal alterations following stereotactic surgery identify retrograde non-Wallerian changes in interrupted axons and provide a new method in identifying and tracing lesioned pathways.
Insights
Magnetic resonance imaging (MRI) after stereotactic surgery revealed novel T1-weighted signal changes. These findings indicate retrograde, non-Wallerian degeneration in interrupted axons, aiding in tracing lesioned pathways.
Area of Science:
- Neurosurgery
- Neuroradiology
- Neuroscience
Background:
- Stereotactic bilateral anterior capsulotomy is a surgical procedure used for treatment-resistant conditions.
- Magnetic resonance imaging (MRI) is crucial for assessing post-surgical anatomical changes.
Purpose of the Study:
- To investigate anatomic changes following MRI-guided stereotactic bilateral anterior capsulotomy.
- To characterize novel MRI signal alterations in lesioned neural pathways.
Main Methods:
- Five patients with major depression or obsessive-compulsive disorder underwent bilateral anterior capsulotomy.
- Postoperative MRI scans were performed at 2 months and 1-4 years after surgery.
- A comparator case with a stroke-induced motor deficit was included.
Main Results:
- A previously undescribed T1-weighted signal increase was observed in specific neural pathways at 2 months post-surgery.
- These T1 signal alterations were not present in T2-weighted or fluid-attenuated inversion recovery sequences.
- The observed changes differed from anterograde Wallerian degeneration, suggesting retrograde axonal alterations.
Conclusions:
- Novel T1-weighted signal alterations following stereotactic surgery have been identified.
- These findings indicate retrograde, non-Wallerian changes in interrupted axons.
- This provides a new method for identifying and tracing lesioned neural pathways.