Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 138-225, Korea.
Radiology. 2012 Nov;265(2):627-37. doi: 10.1148/radiol.12111194. Epub 2012 Sep 25.
To evaluate the accuracy of the size and location of the ablation zone produced by volumetric magnetic resonance (MR) imaging-guided high-intensity focused ultrasound ablation of uterine fibroids on the basis of MR thermometric analysis and to assess the effects of a feedback control technique.
This prospective study was approved by the institutional review board, and written informed consent was obtained. Thirty-three women with 38 uterine fibroids were treated with an MR imaging-guided high-intensity focused ultrasound system capable of volumetric feedback ablation. Size (diameter times length) and location (three-dimensional displacements) of each ablation zone induced by 527 sonications (with [n=471] and without [n=56] feedback) were analyzed according to the thermal dose obtained with MR thermometry. Prospectively defined acceptance ranges of targeting accuracy were ±5 mm in left-right (LR) and craniocaudal (CC) directions and ±12 mm in anteroposterior (AP) direction. Effects of feedback control in 8- and 12-mm treatment cells were evaluated by using a mixed model with repeated observations within patients.
Overall mean sizes of ablation zones produced by 4-, 8-, 12-, and 16-mm treatment cells (with and without feedback) were 4.6 mm±1.4 (standard deviation)×4.4 mm±4.8 (n=13), 8.9 mm±1.9×20.2 mm±6.5 (n=248), 13.0 mm±1.2×29.1 mm±5.6 (n=234), and 18.1 mm±1.4×38.2 mm±7.6 (n=32), respectively. Targeting accuracy values (displacements in absolute values) were 0.9 mm±0.7, 1.2 mm±0.9, and 2.8 mm±2.2 in LR, CC, and AP directions, respectively. Of 527 sonications, 99.8% (526 of 527) were within acceptance ranges. Feedback control had no statistically significant effect on targeting accuracy or ablation zone size. However, variations in ablation zone size were smaller in the feedback control group.
Sonication accuracy of volumetric MR imaging-guided high-intensity focused ultrasound ablation of uterine fibroids appears clinically acceptable and may be further improved by feedback control to produce more consistent ablation zones.
基于磁共振测温分析评估容积磁共振（MR）成像引导高强度聚焦超声消融子宫肌瘤时消融区的大小和位置的准确性，并评估反馈控制技术的效果。
本前瞻性研究经机构审查委员会批准，并获得书面知情同意。33 名患有 38 个子宫肌瘤的女性接受了能够进行容积反馈消融的 MR 成像引导高强度聚焦超声系统治疗。根据 MR 测温获得的热剂量，分析 527 次超声（有[ n = 471]和无[ n = 56]反馈）引起的每个消融区的大小（直径×长度）和位置（三维位移）。根据目标定位准确性的预设接受范围，在左右（LR）和头尾（CC）方向的允许偏差为±5mm，在前后（AP）方向的允许偏差为±12mm。通过对每个患者内的重复观察，采用混合模型评估 8mm 和 12mm 治疗单元的反馈控制效果。
在有和无反馈的情况下，使用 4mm、8mm、12mm 和 16mm 治疗单元治疗后，消融区的平均大小分别为 4.6mm±1.4（标准差）×4.4mm±4.8（ n = 13）、8.9mm±1.9×20.2mm±6.5（ n = 248）、13.0mm±1.2×29.1mm±5.6（ n = 234）和 18.1mm±1.4×38.2mm±7.6（ n = 32）。LR、CC 和 AP 方向的定位精度值（绝对值位移）分别为 0.9mm±0.7、1.2mm±0.9 和 2.8mm±2.2。在 527 次超声中，99.8%（526/527）在接受范围内。反馈控制对定位精度或消融区大小无统计学显著影响。然而，在反馈控制组中，消融区大小的变化更小。
容积 MR 成像引导高强度聚焦超声消融子宫肌瘤的超声准确性在临床上可接受，通过反馈控制可能进一步提高，以产生更一致的消融区。
