目的探讨MRI早期动态增强斜 率(Slope)直方图对骨肉瘤新辅助化疗疗 效评价的价值。方法 对14例经病理证实 的四肢骨肉瘤在新辅助化疗前3天内、化 疗后术前3天内进行MRI平扫及动态增强 扫描，采用MR设备自带后处理软件生成 Slope图，将新辅助化疗前、后的整个瘤 体的Slope图导入基于Matlab的直方图分 析软件获得Slope值分布直方图。将14例 肿瘤按手术病理Huvos分级法分为组织学 反应良好组和组织学反应较差组，比较两 组新辅助化疗前、后Slope直方图和平均 Slope值的变化。结果 骨肉瘤新辅助化疗 后组织学反应良好组(6例)Slope直方图 平均值明显左移，而组织学反应较差组 (8例)Slope直方图显示平均值左移不明 显甚至右移；两组间平均Slope值变化率 的差异有统计学意义(P值=0.008)。结论 Slope直方图有助于评价骨肉瘤新辅助化 疗的疗效。

Objective To discuss the value of early dynamic contrast-enhanced MR imaging Slope histogram to evaluate neoadjuvant chemotherapeutic response of osteosarcoma. Methods Conventional and early dynamic contrast-enhanced MR imaging were performed in 14 patients with pathologically confirmed limb osteosarcoma at two time points: within 3 days before neoadjuvant chemotherapy, and within 3 days before surgery after neoadjuvant chemotherapy. Slope maps before and after neoadjuvant chemotherapy were obtained using built-in workstation processing software. Slope histograms were obtained using a Matlab-based customized software. The patients were divided into the good response group and poor response group according to postoperative Huvos grading pathologically. The change of pre- and post- neoadjuvant chemotherapy Slope histogram and mean Slope value between the two groups were compared. Results The mean value of Slope histogram was obviously shifted to the left in good response group (6 patients). However, the mean value of Slope histogram did not obviously shift to the left or even shift to the right in the poor response group (8 patients).The change of the mean Slope value pre- and post-neoadjuvant chemotherapy was statistically different in the two groups (P=0.008). Conclusion The Slope histogram is helpful for evaluation of neoadjuvant chemotherapeutic response of osteosarcoma.