Department of Radiology, Otto von Guericke University, Medical School, Magdeburg, Germany.
Invest Radiol. 2013 Jun;48(6):422-8. doi: 10.1097/RLI.0b013e3182803dae.
The aims of this study were to develop magnetic resonance (MR)-guided freehand radiofrequency ablation (RFA) using a near-real-time interactive MR platform in an open 1.0-T MR scanner and to determine the feasibility and safety of this new approach in the clinical setting.
The study was performed using an open 1.0-T MR system and a low-pass filter to prevent interaction between the RFA generator and the scanner. Artifact size of the radiofrequency needle was measured in 2 perpendicular views (transversal [tra] and coronal [cor]) in vitro and in the tra orientation in vivo for diagnostic (T1 high resolution isotropic volume excitation [THRIVE]/T2 turbo spin-echo [TSE]) and near-real-time (T1 fast-field-echo [FFE]) imaging. A liver-specific contrast medium (gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid) was administered 20 minutes before the intervention to enhance lesion visibility. Visibility was rated and compared for both interventional and diagnostic imaging sequences using a 10-point grading scale. Intervention time and complications were recorded.
The mean diameter of needle artifact size for interventional T1 FFE was 17.4 ± 0.7 mm (tra) and 17.1 ± 1.1 mm (cor) in vitro and 15.2 ± 1.5 mm (tra) in vivo. Artifact size for diagnostic imaging was 12.5 ± 1.8 mm (tra) and 11.2 ± 1.4 mm (cor) in vitro and 10.5 ± 1.7 mm in vivo using THRIVE and 8.1 ± 2.4 mm (tra) and 10.8 ± 1.8 mm (cor) in vitro and 9.7 ± 2.0 mm (tra) in vivo using T2 TSE. A total of 57 patients with liver malignancies (mean tumor size, 17 ± 7 mm) underwent freehand MR-guided RFA. In all patients, the ablative procedure was technically successful. Lesion visibility of the diagnostic T2 TSE sequence (4 ± 2) was significantly decreased compared with both the diagnostic (THRIVE, 7 ± 2) and interventional (T1 FFE, 8 ± 1) T1-weighted sequences. Mean time to position the applicator was 7.5 ± 2 minutes. Procedure times ranged from 30 to 60 minutes. The mean in-room time was 57 ± 22 minutes. No major complications were recorded.
Magnetic resonance-guided freehand RFA using a near-real-time interactive MR platform in an open 1.0-T MR scanner is feasible, safe, and applicable in clinical routine. The administration of a hepatocyte-specific contrast agent enhances lesion visualization and therefore improves targeting. Without the need for additional sophisticated devices, this new approach simplifies and shortens the RFA procedure compared with previously published methods.
本研究旨在开发一种基于近实时交互式磁共振（MR）平台的开放式 1.0-T 磁共振系统下的自由手持射频消融（RFA）技术，并确定该新技术在临床环境中的可行性和安全性。
本研究采用开放式 1.0-T MR 系统和低通滤波器，以防止 RFA 发生器与扫描仪之间的相互作用。在体外测量射频针的伪影大小，在两个垂直视图（横断[tra]和冠状[cor]）和体内的 tra 方向进行诊断（T1 高分辨率各向同性激发容积[THRIVE]/T2 涡轮自旋回波[TSE]）和近实时（T1 快速场回波[FFE]）成像。在干预前 20 分钟，给予肝特异性对比剂（钆乙氧苯甲基二乙三胺五乙酸）以增强病变的可视性。使用 10 分制评分量表对诊断和介入成像序列的可视性进行评分和比较。记录干预时间和并发症。
介入 T1 FFE 的针伪影大小平均直径为体外 17.4 ± 0.7mm（tra）和 17.1 ± 1.1mm（cor），体内 15.2 ± 1.5mm（tra）。体外诊断成像的伪影大小为 THRIVE 时 12.5 ± 1.8mm（tra）和 11.2 ± 1.4mm（cor），T2 TSE 时 10.5 ± 1.7mm，体内时 9.7 ± 2.0mm（tra）。使用 THRIVE 和 T2 TSE 时，分别为 8.1 ± 2.4mm（tra）和 10.8 ± 1.8mm（cor）。共 57 例肝脏恶性肿瘤患者（平均肿瘤大小为 17 ± 7mm）接受了自由手持磁共振引导的 RFA。在所有患者中，消融程序均技术成功。诊断 T2 TSE 序列（4 ± 2）的病变可视性明显低于诊断（THRIVE，7 ± 2）和介入（T1 FFE，8 ± 1）T1 加权序列。将施源器定位的平均时间为 7.5 ± 2 分钟。手术时间从 30 分钟到 60 分钟不等。平均室内时间为 57 ± 22 分钟。无重大并发症记录。
开放式 1.0-T MR 系统中使用近实时交互式磁共振平台的自由手持 RFA 是可行、安全的，并且适用于临床常规。肝特异性对比剂的给药可增强病变的可视化，从而提高靶向性。与以前发表的方法相比，这种新方法无需额外的复杂设备，简化和缩短了 RFA 过程。
