MRI与4DCT联合指导勾画原发性肝癌患者放疗靶区初步研究*

目的 探讨磁共振成像(MRI)与四维计算机断层扫描(4DCT)图像联合用于原发性肝癌(PLC)患者首次放疗靶区勾画的价值。方法 2019年5月～2021年5月我院收治的56例PLC患者,在放射治疗前,分别行MRI和4DCT检查,将获得的图像上传至工作站,在自动配准结束后以Reg Reveal和Reg Refine行配准和图像质量评估,锁定局部感兴趣区。比较配准前后4DCT不同时相图像中的肿瘤靶区体积、大体内靶区体积,观察T2加权像(MR-T2)图像与4DCT图像配准精度。结果 在4DCT配准后, CT₀₀、CT₁₀、CT₂₀、CT₃₀、CT₄₀、CT₅₀、CT₆₀、CT₇₀、CT₈₀和CT₉₀肿瘤靶区体积分别为(389.8±52.5)cm³、(393.4±59.7)cm³、(390.7±50.3)cm³、(388.5±47.8)cm³、(380.4±40.5)cm³、(379.2±40.6)cm³、(383.7±43.3)cm³、(380.2±41.7)cm³、(371.0±38.9)cm³和(381.7±36.6)cm³,均显著大于配准前【分别为(365.7±29.0)cm³、(360.5±29.2)cm³、(347.4±24.9)cm³、(350.2±27.2)cm³、(351.4±28.5)cm³、(358.4±29.3)cm³、(361.5±34.7)cm³、(357.5±28.8)cm³、(350.3±36.6)cm³和(355.0±34.9)cm³,P＜0.05】;56例PLC患者配准后大体内靶区体积为(468.7±226.2)cm³,显著大于配准前【(410.5±192.5)cm³,P＜0.05】;经门静脉或腹腔干Reg Refine配准后,X、Y、Z轴位移分别为(0.3±0.1)mm、(0.6±0.2)mm和(0.5±0.2)mm,或(0.7±0.2)mm、(0.7±0.3)mm和(0.6±0.2)mm,显著小于自动配准移位【分别为(3.3±0.4)mm、(4.9±0.5)mm和(4.2±0.4)mm或(3.4±0.3)mm、(3.7±0.4)mm和(3.2±0.4)mm,P＜0.05】;MR-T2图像显示肝脏体积为(2002.4±843.7)cm³,4DCT图像显示为(2048.7±937.2)cm³,肝脏体积交叠度为(110.2±22.7)%。结论 首次给PLC患者放疗前行MR-T2联合4DCT检查可精确勾画肿瘤靶区,可能提高放疗效果。

A pilot study of MR and 4DCT images in the delineation of target area in patients with primary liver cancer undergoing first radiotherapy

Objective The purpose of this study was o evaluate magnetic resonance imaging (MRI)and 4-d computed tomography (4DCT) images in the delineation of target area in patients with primary liver cancer (PLC) undergoingfirst radiotherapy. Methods 56 patients with PLC were admitted to our hospital between May 2019 and May 2021, and all patients tended to receive radiotherapy. Before treatment, the patients underwent MRI and 4DCT examinations respectively, and the images were up-loaded to the workstation. After the automatic registration,the Reg Reveal and Reg Refine were applied for further preciseregistration, the image quality was assessed and local regionof interest (ROI) was locked. The tumor target volume and large body target volume in differentstage of 4DCT images were compared before and after registration. The registration accuracy of T2 weighted image (MR-T2) and 4DCT image was observed. Results After 4DCT registration, the tumor target volume atCT₀₀, CT₁₀, CT₂₀, CT₃₀, CT₄₀, CT₅₀, CT₆₀, CT₇₀, CT₈₀ and CT₉₀ were (389.8±52.5)cm³,(393.4±59.7)cm³,(390.7±50.3)cm³,(388.5±47.8)cm³,(380.4±40.5)cm³,(379.2±40.6)cm³,(383.7±43.3)cm³,(380.2±41.7)cm³,(371.0±38.9)cm³ and (381.7±36.6)cm³, all significantly larger than (365.7±29.0)cm³,(360.5±29.2)cm³,(347.4±24.9)cm³,(350.2±27.2)cm³,(351.4±28.5)cm³,(358.4±29.3)cm³,(361.5±34.7)cm³,(357.5±28.8)cm³,(350.3±36.6)cm³ and (355.0±34.9)cm³, P＜0.05] before registration; after registration, the large body target volume in the 56 patients with PLC was (468.7±226.2)cm³, significantly larger than (410.5±192.5)cm³, P＜0.05] before registration; after Reg Refine registration by portal vain or byceliac trunk, the shift at X, Y, Z axis were (0.3±0.1)mm, (0.6±0.2)mm and (0.5±0.2)mm, or (0.7±0.2)mm, (0.7±0.3)mm and (0.6±0.2)mm, all significantly smaller than (3.3±0.4)mm, (4.9±0.5)mm and (4.2±0.4)mm or (3.4±0.3)mm, (3.7±0.4)mm and (3.2±0.4)mm, respectively, P＜0.05] by automatic registration; the liver volume in MR-T2 image was (2002.4±843.7) cm³, the liver volume in 4DCT image was (2048.7±937.2) cm³, and the overlap of liver volume was (110.2±22.7)%. Conclusion Thecombination of MT-T2 and 4DCT for precise delineation of tumor target in patients withPLC before first radiotherapy could help get accurate tumor targets, which might improve the therapy efficacy.