头颈部癌大体肿瘤体积MRI与CT定义比较研究

目的 采用病理标本验证基于MRI、CT定义的头颈部癌大体肿瘤体积(GTV)准确性差异,为临床评价两种影像方法提供依据。方法 选取10只新西兰大白兔建立VX₂鳞癌细胞系头颈部癌模型,6例成功。每只荷瘤兔在同一体位及固定下行头颈部MR和CT扫描,随后处死并置于明胶溶液－70℃固定72 h。采用可定位曲线锯按照与影像扫描相同位置及层厚切割标本来获取病理解剖图像。分别在MRI、CT、病理解剖图像上勾画GTV,计算GTV_MRI、GTV_CT、GTV_SA和体积差异比(VDR),双向分类方差分析和配对t检验比较差异。结果 GTV_MRI、GTV_CT、GTV_SA平均值分别为(8.20±2.56)、(8.40±2.20)、(8.11±2.88) cm³(F=0.06,P=0.943)。VDR_MRI-SA、VDR_CT-SA平均值分别为0.180±0.060、0.309±0.091(t=7.49,P=0.001)。结论 基于MRI的头颈部癌GTV定义的准确性优于CT。

Validation of MRI-or CT-based gross tumor volume delineation in head and neck cancer:a comparative study

Objective To validate the gross tumor volume (GTV) delineation in head and neck cancer based on magnetic resonance imaging (MRI) or computed tomography (CT) by cross-sectional autopsy, and to provide a basis for clinical evaluation of the two imaging methods. Methods Ten New Zealand rabbits were selected for transplantation of VX₂ carcinoma cells, and a head and neck cancer model was successfully established in six rabbits. Each rabbit was fixed and received MRI scan and CT scan in the same body position. Then, they were sacrificed and fixed in gelatin solution (－70℃) for 72 h;all cryopreserved rabbits underwent cross-sectional autopsy using a jig saw, with the same position and sectional thickness as in MRI scan and CT scan, and cross-sectional autopsy images were obtained using a digital single-lens reflex camera. GTVs were separately delineated based on CT, MRI, and cross-sectional autopsy images. The GTV_MRI, GTV_CT, GTV_SA, and volume difference ratios (VDRs) were calculated;two-way classification ANOVA and paired t-test were used for difference analyses. Results The mean values of GTV_MRI, GTV_CT, and GTV_SA were 8.20±2.56, 8.40±2.20, and 8.11±2.88 cm³, respectively, without significant differences among them (F=0.06,P=0.943). The mean values of VDR_MRI-SA and VDR_CT-SA were 0.180±0.060 and 0.309±0.091, respectively, with a significant difference between them (t=7.49, P=0.001). Conclusion The GTV delineation based on MRI is more accurate than that based on CT in head and neck cancer.