Miller Timothy R, Zhuo Jiachen, Eisenberg Howard M, Fishman Paul S, Melhem Elias R, Gullapalli Rao, Gandhi Dheeraj
Department of Diagnostic Radiology, University of Maryland Medical Center, USA.
Department of Neurosurgery, University of Maryland Medical Center, USA.
Neuroradiol J. 2019 Dec;32(6):401-407. doi: 10.1177/1971400919870180. Epub 2019 Aug 13.
Magnetic resonance-guided focused ultrasound ablation of the thalamic ventral intermediate nucleus is a safe and effective treatment for medically refractory essential tremor. However, indirect targeting of the ventral intermediate nucleus using stereotactic coordinates from normal neuroanatomy can be inefficient. We therefore evaluated the feasibility of supplementing this method with direct targeting of the dentato-rubro-thalamic tract.
We retrospectively identified four patients undergoing magnetic resonance-guided focused ultrasound ablation for essential tremor in which preoperative diffusion tractography imaging of the dentato-rubro-thalamic tract was fused with T2 weighted-imaging and utilized for intra-procedural targeting. The size and location of the dentato-rubro-thalamic tract and 24-hour lesion, as well as the center of the stereotactic coordinates, was evaluated. Finally, the amount of overlap between the dentato-rubro-thalamic tract and the lesion was calculated.
The 24-hour lesion size was homogeneous in the cohort (mean 31.3 mm, range 30-32 mm), while there was substantial variation in the dentato-rubro-thalamic tract area (mean 14.3 mm, range 3-24 mm). The center of the stereotactic coordinates and dentato-rubro-thalamic tract diverged by more than 1 mm in mediolateral and anterposterior directions in all patients, while the dentato-rubro-thalamic tract and lesion centers were in close proximity (mean mediolateral separation 1 mm, range 0.1-2.2 mm; mean anteroposterior separation 0.75 mm, range 0.4-1.2 mm). There was greater than 50% coverage of the dentato-rubro-thalamic tract by the lesion in all patients (mean 82.9%, range 66.7-100%). All patients experienced durable tremor relief.
Direct targeting of the dentato-rubro-thalamic tract using diffusion tractography imaging fused to T2 weighted-imaging may be a useful strategy for focused ultrasound treatment of essential tremor. Further investigation of the technique is warranted.
磁共振引导下聚焦超声丘脑腹中间核消融术是治疗药物难治性特发性震颤的一种安全有效的方法。然而，使用正常神经解剖学的立体定向坐标间接靶向腹中间核可能效率不高。因此，我们评估了用直接靶向齿状红核丘脑束来补充该方法的可行性。
我们回顾性地确定了4例接受磁共振引导下聚焦超声丘脑腹中间核消融术治疗特发性震颤的患者，术中将术前齿状红核丘脑束的弥散张量成像与T2加权成像融合，并用于靶点定位。评估齿状红核丘脑束的大小和位置、24小时后的病灶以及立体定向坐标的中心。最后，计算齿状红核丘脑束与病灶之间的重叠量。
该队列中24小时后的病灶大小均匀（平均31.3mm，范围30 - 32mm），而齿状红核丘脑束面积存在显著差异（平均14.3mm，范围3 - 24mm）。所有患者的立体定向坐标中心与齿状红核丘脑束在内外侧和前后方向上的偏差均超过1mm，而齿状红核丘脑束与病灶中心距离较近（平均内外侧间距1mm，范围0.1 - 2.2mm；平均前后间距0.75mm，范围0.4 - 1.2mm）。所有患者的病灶对齿状红核丘脑束的覆盖均超过50%（平均82.9%，范围66.7 - 100%）。所有患者的震颤均得到持久缓解。
将弥散张量成像与T2加权成像融合后直接靶向齿状红核丘脑束，对于聚焦超声治疗特发性震颤可能是一种有用的策略。有必要对该技术进行进一步研究。
