骨肉瘤侵袭范围的MRI测量与确定合理切除平面的相关研究

目的 探讨MRI判断肢体骨肉瘤局部侵袭范围的准确性及据此确定保肢术中的安全切除平面。方法 冷冻后的骨肉瘤截肢标本19例，按照MRI确定的相应层面，在断层切片机上切取厚度为0＋5cm的水平断层切片，肉眼测量肿瘤的软组织侵袭范围，并以0．5cm的间隔做连续病理切片，确定显微镜下肿瘤软组织侵袭范围。然后按照MRI确定的相应层面，纵向剖开标本，测量肿瘤的髓内肉眼范围，并以0．5cm的间隔做连续病理切片，确定显微镜下肿瘤的髓内侵袭范围。分别将肿瘤X线、MRI的侵袭范围与肉眼范围和病理侵袭范围进行统计学比较。结果 （1）X线、MRI、肉眼和病理测量的骨肉瘤髓内侵袭范围分别为（11.18±8.64）cm、（15.37±9．73）cm、（14.77±9.38）cm、（14．58±9.51）cm，经统计学分析MRI所确定的髓内侵袭范围与病理侵袭范围之间无显著性差异（P〉0．05）。（2）MRI、肉眼和病理测量的骨肉瘤软组织侵袭范围分别为：横径（6．62±2．23）cm、（6.22±2．21）cm、（6．23±2.38）cm；纵径（7.15±2.37）cm，（6．57±1.80）cm、（6.58±1.94）cm，经统计学分析MRI所确定的软组织侵袭范围与病理侵袭范围之间无显著性差异（P〉0.05）。MRI对骨肉瘤髓内和软组织的测量值均不超过病理范围10mm。结论 在确定骨肉瘤手术切除安全界面上，MRI较X线片有更高的准确性。以MRI为依据，在瘤体外2～3cm处截骨，软组织外1．0～1.5cm作为切除界面是安全可靠的。

The margining of osteosarcoma on MRI and its significance in surgical planning

Objective To investigate the accuracy of osteosarcoma marginning on MRI and its significance in surgical planning in salvage operations. Methods Nineteen amputated extremities of osteosarcoma were kept at -20℃ for 48 hours. According to the corresponding plane which was defined on MRI, 0.5cm horizontal slice was made from specimens with microtome. The gross margin of osteosarcoma was defined, then the sequence pathological slice was made at 0.5cm interval. The marging of osteosarcoma was defined by microscopy, Then the specimen was split sagitally, according to the corresponding plane was defined on MRI, The gross margin of intra-medullary invasion of osteosarcoma were determined, then the sequence pathological slice was made with 0,5cm interval, The intra-medullary margin of osteosarcoma was defined by microscopy, Results （1） The margin measure of intra-medullary invasion on plain radiographs was （11.18 ± 8.64）cm, （15.37 ± 9.73）cm on MRI, （14.77 ± 9.38）cm in gross pathology and （14.58 ± 9.51）cm in microscopic pathology, There was not statistically significant difference in intramedullary margin measure between MRI and the pathological scoping （P〉0.05）. （2） The transversal and longitudinal margin of tumor in soft tissue was 6.62 ± 2.23cm and 7.15 ± 2.37cm on MRI, 6.22 ± 2.21cm and 6.57 ± 1.80 cm in gross pathology and 6.23 ± 2.38cm and 6.58 ± 1.94cm in microscopic pathology, respectively, There was not statistically significant difference in soft tissue margin measure between MRI and the pathological scoping （P〉0.05）, Conclusions MRI is more precise than x-ray in determining surgical margin of osteosarcoma, It is reasonable to define safe extra-marginal resection as 2-3cm beyond the intra-medullary margin and 1-1.5cm beyond the soft tissue margin measured by MRI.