Külling D, Treiber K, Fried M, Marincek B, Bauerfeind P
Dept. of Internal Medicine, University Hospital of Zurich, Switzerland.
Endoscopy. 2000 Dec;32(12):966-70. doi: 10.1055/s-2000-9630.
Endoscopic laser therapy involves a risk of perforation, mainly because the depth of tissue destruction is not visible. Magnetic resonance (MR) imaging is capable of showing temperature changes, and is therefore suitable for monitoring thermal therapies such as laser. This animal study assessed the feasibility of real-time MR monitoring of endoscopic laser applications in the gastrointestinal tract.
The procedures were carried out using an MR-compatible endoscope in three live pigs in a 0.5-Tesla interventional MR system. Nd:YAG laser applications were performed in the lower gastrointestinal tract (n = 7) and upper gastrointestinal tract (n = 5), and were monitored using real-time color-coded T1-weighted gradient echo sequences. The postmortem macroscopic tissue coagulation sizes were compared with the lesion diameters seen on real-time MR.
The endoscope did not cause any artifacts during continuous MR imaging. Ten of the twelve laser lesions were visible with temperature-sensitive MR imaging, and their sizes correlated well with the diameters of the postmortem macroscopic coagulation zones (r = 0.76, P = 0.009). Two laser lesions were not visible on MR due to technical limitations inherent with the healthy animal model.
The formation of endoscopic laser lesions in the porcine gastrointestinal tract can be accurately visualized using real-time temperature-sensitive MR imaging. This new technique has the potential to spare healthy tissue while ensuring full treatment coverage of the targeted lesion with fewer therapy sessions.
内镜激光治疗存在穿孔风险，主要原因是组织破坏深度不可见。磁共振（MR）成像能够显示温度变化，因此适用于监测激光等热疗法。本动物研究评估了胃肠道内镜激光应用实时MR监测的可行性。
在一台0.5特斯拉介入式MR系统中，对三头活猪使用兼容MR的内镜进行操作。在下消化道（n = 7）和上消化道（n = 5）进行钕钇铝石榴石激光应用，并使用实时彩色编码T1加权梯度回波序列进行监测。将死后大体组织凝固大小与实时MR上看到的病变直径进行比较。
在连续MR成像过程中，内镜未产生任何伪影。12个激光损伤中有10个在温度敏感MR成像中可见，其大小与死后大体凝固区直径相关性良好（r = 0.76，P = 0.009）。由于健康动物模型固有的技术限制，有2个激光损伤在MR上不可见。
使用实时温度敏感MR成像可准确显示猪胃肠道内镜激光损伤的形成。这项新技术有可能在确保用较少治疗次数完全覆盖目标病变的同时，保留健康组织。
