Wijlemans Joost W, de Greef Martijn, Schubert Gerald, Moonen Chrit T W, van den Bosch Maurice A A J, Ries Mario
Department of Radiology, University Medical Center Utrecht, E01.132, P.O. Box 85500, Utrecht 3508 GA, The Netherlands.
Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands.
Acad Radiol. 2014 Dec;21(12):1597-602. doi: 10.1016/j.acra.2014.06.015. Epub 2014 Aug 7.
Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of tumors in the liver dome is challenging because of the presence of air in the costophrenic angle. In this study, we used a porcine liver model and a clinical MR-HIFU system to assess the feasibility and safety of using intrapleural fluid infusion (IPI) to create an acoustic window for MR-HIFU ablation in the liver dome.
Healthy adult Dalland land pigs (n = 6) under general anesthesia were used with animal committee approval. Degassed saline (200-800 mL) was infused into the intrapleural space under ultrasound guidance. A clinical 1.5-T MR-HIFU system was used to perform sonications (4-mm treatment cells, 300-450 W, 20-30 seconds) in the liver dome under real-time MR thermometry. An intercostal firing technique was used to prevent rib heating in one experiment. Technical success was defined as a temperature increase (>10°C) in the target area. After termination, the animal was examined for thermal damage to liver, diaphragm, pleura, lung, or intercostal muscle.
An acoustic window was established in all animals. A temperature increase in the target area was achieved in all animals (max. 47°C-67°C). MR thermometry showed no heating outside the target area. Intercostal firing effectively reduced rib heating (55°C vs. 42°C). Postmortem examination revealed no unwanted thermal damage. One complication occurred, in the first experiment, because of an ill-suited needle (displacement of the needle).
The results indicate that IPI may be used safely to assist MR-HIFU ablation of tumors in the liver dome. For reliable tissue coagulation, IPI must be combined with an intercostal sonication technique. Considering the proportion of patients with tumors in the liver dome, IPI widens the applicability of MR-HIFU ablation for liver tumors considerably.
由于肋膈角存在空气，磁共振引导下高强度聚焦超声（MR-HIFU）消融肝顶部肿瘤具有挑战性。在本研究中，我们使用猪肝模型和临床MR-HIFU系统，评估通过胸腔内液体输注（IPI）为肝顶部MR-HIFU消融创建声窗的可行性和安全性。
在动物委员会批准下，使用健康成年达兰猪（n = 6），并实施全身麻醉。在超声引导下将脱气盐水（200 - 800 mL）注入胸腔。使用临床1.5-T MR-HIFU系统在实时磁共振测温下对肝顶部进行超声照射（治疗单元4 mm，300 - 450 W，20 - 30秒）。在一项实验中采用肋间发射技术以防止肋骨发热。技术成功定义为靶区温度升高（>10°C）。实验结束后，检查动物肝脏、膈肌、胸膜、肺或肋间肌的热损伤情况。
所有动物均成功建立声窗。所有动物靶区均实现温度升高（最高47°C - 67°C）。磁共振测温显示靶区外无发热。肋间发射有效减少了肋骨发热（55°C对42°C）。尸检未发现意外热损伤。在第一个实验中发生了1例并发症，原因是针不合适（针移位）。
结果表明IPI可安全用于辅助MR-HIFU消融肝顶部肿瘤。为实现可靠的组织凝固，IPI必须与肋间超声照射技术相结合。考虑到肝顶部肿瘤患者的比例，IPI显著拓宽了MR-HIFU消融肝肿瘤的适用范围。
