Blitz Sarah E, Chua Melissa M J, Ng Patrick, Segar David J, Jha Rohan, McDannold Nathan J, DeSalvo Matthew N, Rolston John D, Cosgrove G Rees
Harvard Medical School, Boston, MA, United States.
Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
Front Neurol. 2023 Oct 6;14:1272425. doi: 10.3389/fneur.2023.1272425. eCollection 2023.
Magnetic-resonance-guided focused ultrasound (MRgFUS) thalamotomy uses multiple converging high-energy ultrasonic beams to produce thermal lesions in the thalamus. Early postoperative MR imaging demonstrates the location and extent of the lesion, but there is no consensus on the utility or frequency of postoperative imaging. We aimed to evaluate the evolution of MRgFUS lesions and describe the incidence, predictors, and clinical effects of lesion persistence in a large patient cohort.
A total of 215 unilateral MRgFUS thalamotomy procedures for essential tremor (ET) by a single surgeon were retrospectively analyzed. All patients had MR imaging 1 day postoperatively; 106 had imaging at 3 months and 32 had imaging at 1 year. Thin cut (2 mm) axial and coronal T2-weighted MRIs at these timepoints were analyzed visually on a binary scale for lesion presence and when visible, lesion volumes were measured. SWI and DWI sequences were also analyzed when available. Clinical outcomes including tremor scores and side effects were recorded at these same time points. We analyzed if patient characteristics (age, skull density ratio), preoperative tremor score, and sonication parameters influenced lesion evolution and if imaging characteristics correlated with clinical outcomes.
Visible lesions were present in all patients 1 day post- MRgFUS and measured 307.4 ± 128.7 mm. At 3 months, residual lesions (excluding patients where lesions were not visible) were 83.6% smaller and detectable in only 54.7% of patients ( = 58). At 1 year, residual lesions were detected in 50.0% of patients ( = 16) and were 90.7% smaller than 24 h and 46.5% smaller than 3 months. Lesions were more frequently visible on SWI (100%, = 17), DWI ( = 38, 97.4%) and ADC ( = 36, 92.3%). At 3 months, fewer treatment sonications, higher maximum power, and greater distance between individual sonications led to larger lesion volumes. Volume at 24 h did not predict if a lesion was visible later. Lesion visibility at 3 months predicted sensory side effects but was not correlated with tremor outcomes.
Overall, lesions are visible on T2-weighted MRI in about half of patients at both 3 months and 1 year post-MRgFUS thalamotomy. Certain sonication parameters significantly predicted persistent volume, but residual lesions did not correlate with tremor outcomes.
磁共振引导聚焦超声（MRgFUS）丘脑切开术使用多个汇聚的高能超声束在丘脑中产生热损伤。术后早期的磁共振成像可显示损伤的位置和范围，但对于术后成像的效用或频率尚无共识。我们旨在评估MRgFUS损伤的演变，并描述大型患者队列中损伤持续存在的发生率、预测因素和临床效果。
回顾性分析了由一位外科医生进行的215例用于治疗特发性震颤（ET）的单侧MRgFUS丘脑切开术。所有患者在术后1天进行了磁共振成像；106例在3个月时进行了成像，32例在1年时进行了成像。在这些时间点的薄层（2毫米）轴向和冠状T2加权磁共振成像通过二元尺度进行视觉分析，以确定损伤是否存在，如有可见损伤，则测量其体积。如有可用，还对磁敏感加权成像（SWI）和扩散加权成像（DWI）序列进行了分析。在这些相同时间点记录包括震颤评分和副作用在内的临床结果。我们分析了患者特征（年龄、颅骨密度比）、术前震颤评分和超声参数是否影响损伤演变，以及成像特征是否与临床结果相关。
在MRgFUS术后1天，所有患者均可见损伤，平均体积为307.4±128.7立方毫米。在3个月时，残留损伤（不包括损伤不可见的患者）缩小了83.6%，仅在54.7%的患者中可检测到（n=58）。在1年时，50.0%的患者（n=16）检测到残留损伤，比术后24小时缩小了90.7%，比3个月时缩小了46.5%。在SWI（100%，n=17）、DWI（n=38，97.4%）和表观扩散系数图（ADC，n=36，92.3%）上，损伤更常可见。在3个月时，治疗超声次数越少、最大功率越高以及单个超声之间的距离越大，导致损伤体积越大。术后24小时的损伤体积无法预测损伤后期是否可见。3个月时损伤的可见性可预测感觉副作用，但与震颤结果无关。
总体而言，在MRgFUS丘脑切开术后3个月和1年时，约一半的患者在T2加权磁共振成像上可见损伤。某些超声参数显著预测了损伤的持续体积，但残留损伤与震颤结果无关。
