Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, Japan 860-0811.
Skeletal Radiol. 2010 Feb;39(2):141-6. doi: 10.1007/s00256-009-0830-7. Epub 2009 Nov 19.
The objective of this study was to evaluate whether the average apparent diffusion coefficient (ADC) or the minimum ADC is more useful for evaluating the chemotherapeutic response of osteosarcoma.
Twenty-two patients with osteosarcoma were examined in this study. Diffusion-weighted (DW) and magnetic resonance (MR) images were performed for all patients before and after chemotherapy. The pre- and post-chemotherapy values were obtained both in the average and minimum ADC. The pre-chemotherapy values of the average ADC and minimum ADC respectively were compared with the post-chemotherapy values. In addition, the ADC ratios ([ADC(post) - ADC(pre)] / ADC(pre)) were calculated using the average ADC and the minimum ADC. Twenty-two patients with osteosarcomas were divided into two groups, those with a good response to chemotherapy (> or = 90% tumor necrosis, n = 7) and those with a poor response (< 90% tumor necrosis, n = 15). The average ADC ratio and the minimum ADC ratio of the two groups were compared.
With both the average ADC and the minimum ADC, post-chemotherapy values were significantly higher than pre-chemotherapy values (P < 0.05). The patients with a good response had a significantly higher minimum ADC ratio than those with a poor response (1.01 + or - 0.22 and 0.55 + or - 0.29 respectively, P < 0.05). However, with regard to the average ADC ratio, no significant difference was observed between the two groups (0.66 + or - 0.18 and 0.46 + or - 0.31 respectively, P = 0.19).
The minimum ADC is useful for evaluating the chemotherapeutic response of osteosarcoma.
本研究旨在评估平均表观扩散系数（ADC）或最小 ADC 更有助于评估骨肉瘤的化疗反应。
本研究共纳入 22 例骨肉瘤患者。所有患者均在化疗前后行弥散加权（DW）和磁共振（MR）成像。分别获得化疗前后的平均 ADC 和最小 ADC 值。分别比较化疗前平均 ADC 和最小 ADC 值与化疗后值。此外，还分别使用平均 ADC 和最小 ADC 计算 ADC 比值([ADC(post)-ADC(pre)]/ADC(pre))。将 22 例骨肉瘤患者分为化疗反应良好组（>90%肿瘤坏死，n=7）和化疗反应不良组（<90%肿瘤坏死，n=15）。比较两组的平均 ADC 比值和最小 ADC 比值。
平均 ADC 和最小 ADC 的化疗后值均显著高于化疗前值（P<0.05）。化疗反应良好组的最小 ADC 比值显著高于化疗反应不良组（分别为 1.01±0.22 和 0.55±0.29，P<0.05）。然而，两组间平均 ADC 比值无显著差异（分别为 0.66±0.18 和 0.46±0.31，P=0.19）。
最小 ADC 有助于评估骨肉瘤的化疗反应。
