含软骨基质型肉瘤的MR钆喷替酸葡甲胺增强和扩散加权成像特点

Characterization of chondroid matrix-forming sarcomas： gadolinium-enhanced and diffusion weighted MR imaging

目的 评价含软骨基质型肉瘤的MR Gd-DTPA增强和DWI特点.方法 在1.5 T MR机上对14例含软骨基质型肉瘤（10例软骨肉瘤和4例成软骨型骨肉瘤）和13例其他类型骨肉瘤行MR Gd-DTPA增强和DWI.DWI采用单次激发平面回波成像（SS-EPI）序列,b值分别取0、700 s/mm^2,在GE Functool后处理软件上测定肿瘤的ADC值.评价肿瘤的MRI对比强化特点,并比较ADC值差异.含软骨基质型肉瘤与其他类型骨肉瘤的ADC值两组间比较采用独立样本t检验;软骨肉瘤与成软骨型骨肉瘤的ADC值两组间采用秩和检验.结果 在14例含软骨基质型肉瘤中,间隔结节状强化者有12例,边缘强化有14例.13例其他类型骨肉瘤均表现为不均匀强化.含软骨基质型肉瘤的平均ADC值[（2.56±0.35）×10^-3mm^2/s]高于其他类型骨肉瘤的平均ADC值[（1.16±0.20）×10^-3 mm^2/s]（t=12.704,P〈0.01）;软骨肉瘤的ADC值与成软骨型骨肉瘤的ADC值的差异无统计学意义（Z=0.507,P=0.959）.结论 Gd-DTPA增强MRI和DWI对区别含软骨基质型肉瘤与其他类型骨肉瘤有一定价值.

Objective To study the Gadolinium-enhanced MRI and diffusion weighted imaging （DWI） characteristics of the chondroid matrix-forming sarcomas.Methods Contrast-enhanced MRI and DWI were performed in 14 eases of chondroid matrix-forming sarcomas （10 chondrosarcomas,4 chondroblastic esteosarcomas） and 13 cases of other types of osteosarcomas.DWI was obtained with a single-shot echo-planar imaging （EPI） sequence using a 1.5 T MR imager with two different b values of 0 and 700 s/mm2.The apparent diffusion coefficient （ADC） values were obtained in GE Functiontool software.The contrast-enhancement pattern was evaluated and the ADC values of ehondroid matrix-forming sarcomas was compared with that of other types of asteosarcoma.Independent sample t-test was performed to evaluate the difference of ADC values between the group of chondroid matrix-forming sarcoma and the group of other types of osteosarcoma.In addition, nonparametrie test was used to assess the difference of ADC values between the chondrosareoma and the chondroblastic osteosarcoma.P value less than 0.05 was considered to represent a statistical significance.Results For 14 eases of ehondroid matrix-forming sarcomas, peripheral enhancement was found in all cases, septonodular enhancement was identified in 12 cases.While 13 eases of other types of osteosarcowas demonstrated heterogeneous enhancement.The mean ADC value of chondroid matrix-forming sarcomas [（2.56 ±0.35） × 10 ^-3 mm^2/s] was significantly higher than that of other types of osteosarcoma [（ 1.16±0.20） × 10^-3 mm^2/s] （t = 12.704,P 〈0.O1 ）.There was no significant difference in the ADC value between the chondrosarcoma and the chondroblastie osteesarcama（Z =0.507 ,P =0.959）.Conclusion Contrast-enhanced MRI and DWI can improve differentiation between chondroid matrix-forming sarcomas and other types of osteosarcomas.