肝癌冷冻消融治疗中CT和MRI引导效果对照研究

目的 探讨CT和MR两种影像技术在肝癌冷冻消融治疗中的价值.方法 121例肝癌患者共131个病灶行氩氦刀治疗,其中男73例、女48例,平均年龄(60±8)岁,61例行CT引导下冷冻消融、60例行MR引导下冷冻消融.CT引导采用大孔径16层扫描仪,带有CT透视功能;MR引导采用0.35 T开放式扫描仪,辅助红外导航仪,应用快速梯度回波和快速自旋回波扫描序列.氩氦刀采用MR兼容冷冻系统,冷冻探针为17 G、外径1.47 mm.根据病灶位置、形态、毗邻结构,采用多针组合,适形冷冻.冷冻消融模式为2次冻-融循环消融法,术中间断扫描监测病灶消融情况.以平均扫描时间、病灶显示及冰球监测、肿瘤消融有效率、并发症、生存时间为评价指标,肿瘤消融有效率的比较采用x2检验.结果 CT引导平均扫描时间为(5.6±1.8)min,MR引导平均扫描时间(22.0±2.6)min.CT在病灶精细程度及肋骨等结构的显示方面优于MR;CT扫描中金属探针可以产生伪影,难于显示碘油栓塞后病灶的冰球形成情况.MR在显示、导引和监测邻近膈肌、肝门、胆囊区等特殊部位病灶方面优于CT;而且MR不受高密度栓塞剂及金属探针的影响,在显示病灶、监测冰球形成和病灶消融情况等方面优于CT.但是,MR扫描时间长,低场强开放式MR图像质量不及CT.两组病例随访12个月,CT引导组和MR引导组1年生存率分别为90.2%(55/61)、90.0%(54/60),术后1个月两组病例肿瘤消融有效率分别为75.4%(46/61)、83.4%(50/60).(x2检验=4.4056,P＜0.05).结论 CT引导快速直接,尤其对穿刺路径中的肋骨等结构显示优于MR.MR具有多平面成像对显示病灶与肿瘤的关系,监测治疗效果方面优于CT,尤其在显示、导引和监测邻近膈肌、肝门、胆囊区等特殊部位病灶的穿刺消融优于CT引导.

Comparative study of CT and MR guided cryoablation for hepatic tumors

Objective To compare CT and MR imaging in guiding and monitoring cryoablation of hepatic tumors. Methods A total of 131 lesions in 121 patients with malignant tumors of liver were treated with imaging-guided percutaneous cryotherapy. There were 73 males and 48 females, mean age 60 years. Of the 121 patients, 61 patients had cryoablation under CT guidance and 60 patients under the guidance of MRI. CT-guidance was performed with the Philips big-bore CT in spiral mode, with 5 mm slice thickness.The MR guidance was performed with GE 0.35 T scanner assisted with infrared navigator (Xinaomdt), and both fast gradient echo sequence and fast spin-echo sequence were used. The cryoablation system is a magnetic resonance compatible system (Galil, Israel), equipped with 17 G cryoprobes that are 1.47 mm in outside diameter. A combination of multiple eryo-probes and conformal cryoablation were adopted in accordance with the location, the shape and the adjacent structure of each lesion. Each cryoablation included two freezing-thawing cycles. Scanning was performed intermittently during the operation to monitor the degree of ablation. The mean scanning time, the lesion depiction and ablation process monitoring, the efficacies of lesion ablation, complications,and survival time were analyzed with x2 test Results The mean scanning time was (5.6±1.8)min for CT and (22.0±2.6)min for MR. CT provideda good depiction of the lesion and the ribs which were poorly displayed on MR images. The metal probe could create artifacts on the CT images and it was difficult for CT to show the formation of ice ball of the lesion formed after embolization with lipiodol. MR was superior to CT in displaying, guiding and monitoring of ablation of lesions near such special ragions as the diaphragm dome, the hepatic hilum, and the gallbladder. MR was not affected by high-density embolization material and the metal probes, and thus was superior to CT in depicting the lesion,and monitoring the formation of ice ball and the process of lesion ablation, etc.However, MR scan was time consuming, and image quality of low-field open MR was less desirable than that of CT. The 12-month overall survival rates were 90.2%(55/61) and 90.0%(54/60), respectively. The overall efficacies of lesion ablation were 75.4%(46/61) and 83.4%(50/60), respectively. Conclusion CT has advantages of fast scanning and good display of such structures as ribs in the path of puncture as compared with MR. MR can display a lesion with multi-planar imaging, and is superior to CT in monitoring the procedure of ablation,especially in displaying, guiding and monitoring ablation of lesions near such special regions as the diaphragm dome, the hepatic hilum, and the gallbladder.