MR增强扫描评估HIFU治疗原发骨肉瘤的短期疗效

目的 评估MR平扫和增强扫描在高强度聚焦超声(HIFU)治疗原发骨肉瘤短期疗效随访中的价值。 方法 回顾性分析11例原发骨肉瘤患者HIFU治疗前后的MR平扫和增强图像,观察病灶HIFU治疗前后的信号变化和强化特点。 结果 HIFU治疗前11例原发骨肉瘤T1WI以低信号为主、T2WI以高信号为主的混杂信号,增强扫描呈不同程度强化。HIFU治疗后病灶T1WI信号增高,T2WI信号减低;8例治疗1个月后病灶未见强化,其周围区域见条带样强化,3~4个月后呈线样强化;1例治疗1个月后在病变骨干内见片状强化;1例治疗1个月后在病灶边缘出现结节样强化,再次HIFU治疗后强化消失,病灶周围见条带状强化;1例治疗后与治疗前强化形式相似,再次HIFU治疗后病灶未见强化,周围出现线样强化带。 结论 MR增强扫描能准确评估原发骨肉瘤HIFU治疗后的短期疗效;根据常规MR平扫的信号改变不能准确判断肿瘤完全坏死或残留。

Evaluation on short-term effect of high intensity focused ultrasound ablation for osteosarcoma with enhanced MRI

Objective To observe the value of plain and enhanced MR scan for evaluation on short-term effect of high intensity focused ultrasound (HIFU) for osteosarcoma. Methods Retrospective analysis of plain and enhanced MR images was done in 11 patients with osteosarcoma before and after HIFU treatment, and the signal changes and enhanced features of lesions before and after HIFU treatment were observed. Results Before HIFU treatment, tumors presented as mainly hypointensity on T1WI, heterogeneous hyperintensity on T2WI, and enhanced in different degrees in all 11 patients. The signal increased on T1WI, reduced on T2WI after HIFU treatment. No enhancement in the lesion area was found in 8 patients, strip enhancement around the treated area was noticed 1 month after treatment, then line enhancement was detected 3 to 4 months after treatment. Lamellar enhancement in the affected diaphyses was found in 1 patient. Nodular enhancement at the edge of the affected lesion 1 month after treatment was found in another one, then enhancement disappeared after the second treatment, and bands enhancement appeared instead. Similar enhancement was noticed in 1 patient before and after the treatment in the lesion area, whereas no enhancement was found after the second HIFU treatment, while line enhancement presented around the lesion. Conclusion Contrast-enhanced MRI can be used to accurately evaluate the short-term effect of HIFU for osteosarcoma. Complete necrosis or residual of tumor can not be judged accurately with routine MRI.