Characterization of chondroblastic osteosarcoma: gadolinium-enhanced versus diffusion-weighted MR imaging.

Purpose To detect differences in magnetic resonance imaging (MRI) between chondroblastic osteosarcoma and the other types of osteosarcomas or chondrosarcomas using gadolinium-enhanced versus diffusion-weighted sequences. Materials and Methods Contrast-enhanced MRI and diffusion-weighted imaging (DWI) were performed in five chondroblastic osteosarcoma (CO) cases, 17 other types of osteosarcomas (OS), and 18 chondrosarcomas (CS). DWI was obtained with a single-shot echo-planar imaging (EPI) sequence using a 1.5T MR imager. The apparent diffusion coefficients (ADCs) of the minimum and maximum values were also obtained. The contrast-enhancement pattern was evaluated and minimum-maximum ADC value of CO was compared with other types of OS and CS. Results Both CO and CS showed a similar enhancement pattern; both showed septonodular and peripheral rim enhancement. The minimum ADC value of CO (1.24 ± 0.10 × 10−3mm2/sec) was significantly higher than that of other types of OS (0.84 ± 0.15 × 10−3mm2/sec) and was significantly lower than that of CS (1.64 ± 0.20 × 10−3mm2/sec). In addition, the maximum ADC value of CO (2.28 ± 0.20 × 10−3mm2/sec) was significantly higher than that of other types of OS (1.33 ± 0.26 × 10−3mm2/sec). Conclusion DWI appears to be more useful for differentiating between chondroblastic osteosarcoma and chondrosarcoma or other types of osteosarcoma than Gd-enhanced MRI. J. Magn. Reson. Imaging 2009;29:895–900. © 2009 Wiley-Liss, Inc.