移植骨肉瘤磁共振弥散加权成像特点及价值

目的探讨大鼠骨肉瘤磁共振弥散加权成像(DWI)特点及其判断骨肉瘤坏死区的价值。方法将UMR-106细胞接种于SD大鼠背部皮下成瘤,对肿瘤行MRI常规扫描及DWI成像并做病理对照。结果活肿瘤细胞区血管横断面积百分比与ADC值无相关性。增强扫描确定肿瘤坏死区的敏感性为86.7%(13/15),特异性为38.5%(15/39),准确性为51.9%(28/54)。ADC值确定肿瘤坏死区的敏感性为93.3%(14/15),特异性为94.9%(37/39),准确性为94.4%(51/54)。结论b值较大时,组织微灌注对大鼠骨肉瘤ADC值影响很小。DWI较传统MRI序列及增强扫描能更早期分辨骨肉瘤坏死区。

A Study of MR Diffusion-Weighted Imaging of Implanted Osteosarcoma

Objective To evaluate the characteristic of DWI of SD rat osteosarcoma and the role of DWI in the identification of the necrosis of the osteosarcoma. Methods The osteosarcomas were developed by transplanting tumor cells(UMR-106) in the back of SD rats by subcutaneous injection. The planted tumors were scanned with MR conventional sequences. EPI-DWI were also performed. The MR images were compared with the pathologic sections. Results The percentage of the total blood vessel areas in the axial sections of the tumors did not correlate to its corresponding ADC values. The necrotic areas of the tumors could be identified by contrast enhanced T_ 1 -SE, and its sensitivity was 86.7% (13/15), specificity was 38.5%(15/39) and veracity was 51.9% (28/54). It was feasible to identify the necrotic regions by ADC values, and its sensitivity was 93.3% (14/15), specificity was 94.9% (37/39) and veracity was 94.4% (51/54).Conclusions The microcirculation of the tumors can hardly affect its corresponding ADC values with high b value. The necrotic areas of the SD rat osteosarcomas could be differentiated by DWI more accurately and earlier than traditional MRI sequences and post contrast scan.