Tomlinson F H, Jack C R, Kelly P J
Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota.
J Neurosurg. 1991 Apr;74(4):579-84. doi: 10.3171/jns.1991.74.4.0579.
Serial postoperative magnetic resonance (MR) studies were obtained in 21 patients who underwent somatotopically placed stereotactic radiofrequency (rf) ventralis lateralis thalamotomy for the control of movement disorders. The MR studies were reviewed to determine the MR characteristics of early-phase (less than or equal to 7 days) and late-phase (8 days to 5 months) lesions. Surgery was performed for the control of parkinsonian tremor (14 cases), intention tremor (six cases), and essential tremor (one case). Single rf lesions were made with an electrode (1.6 mm in diameter, 3 mm in tip length) heated to 78 degrees C for 60 seconds. On MR images of the lesions, three distinct concentric zones were identified, described as follows (from the center outward). Zone 1 gives increased signal on long-relaxation time (TR) (T2-weighted) MR images in early- and late-phase lesions and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. Zone 2 gives decreased signal on long-TR (T2-weighted) images in early- and late-phase lesions; it gives isointense signal on short-TR (T1-weighted) images in early-phase lesions only. Zone 3 gives increased signal on long-TR (T2-weighted) images in early-phase lesions only and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. It is considered that in early-phase lesions, Zone 2, with a mean diameter of 7.3 mm on axial long-TR (T2-weighted) imaging, represents an area of hemorrhagic coagulation necrosis. In late-phase lesions, Zone 2, with a mean diameter of 5.0 mm on axial long-TR (T2-weighted) imaging, represents hemosiderin deposition. Zone 3 likely represents edema, and this zone disappears between the early and late periods. From regression analysis, lesion size began to stabilize at approximately 7 months with a mature lesion diameter of 3.3 mm. Long-term follow-up monitoring (median 16 months) showed good tremor control. Based on clinical and radiological findings, the authors conclude that forms of hemoglobin are suitable markers to assess the size of rf lesions. Serial MR imaging provides a noninvasive means of studying the evolution of rf thalamotomy lesions.
对21例行躯体定位立体定向射频腹外侧丘脑切开术以控制运动障碍的患者进行了术后系列磁共振（MR）研究。回顾MR研究以确定早期（小于或等于7天）和晚期（8天至5个月）病变的MR特征。手术用于控制帕金森震颤（14例）、意向性震颤（6例）和特发性震颤（1例）。使用直径1.6mm、尖端长度3mm的电极进行单次射频损伤，加热至78摄氏度，持续60秒。在病变的MR图像上，识别出三个不同的同心区，描述如下（从中心向外）。区域1在早期和晚期病变的长弛豫时间（TR）（T2加权）MR图像上信号增强，仅在早期病变的短TR（T1加权）MR图像上信号减弱。区域2在早期和晚期病变的长TR（T2加权）图像上信号减弱；仅在早期病变的短TR（T1加权）图像上呈等信号。区域3仅在早期病变的长TR（T2加权）图像上信号增强，仅在早期病变的短TR（T1加权）MR图像上信号减弱。据认为，在早期病变中，区域2在轴位长TR（T2加权）成像上平均直径为7.3mm，代表出血性凝固性坏死区域。在晚期病变中，区域2在轴位长TR（T2加权）成像上平均直径为5.0mm，代表含铁血黄素沉积。区域3可能代表水肿，该区域在早期和晚期之间消失。通过回归分析，病变大小在约7个月时开始稳定，成熟病变直径为3.3mm。长期随访监测（中位时间16个月）显示震颤控制良好。基于临床和影像学发现，作者得出结论，血红蛋白形式是评估射频损伤大小的合适标志物。系列MR成像提供了一种研究射频丘脑切开术病变演变的非侵入性方法。
