【摘要】 目的探讨股骨头缺血坏死MRIT2WI上“双线征”与化学位移伪影之间的关系。方法前瞻性研究130例临床及影像学诊断股骨头缺血坏死患者,从中挑选出48例(60髋)MRIT2WI上出现“双线征”的病例,进行不同扫描序列检查。并对其中1髋进行MRI与病理对照研究。结果1.5TMRI机对化学位移伪影敏感性高于0.5TMRI机。20个股骨头T1WI改变频率编码后,单线变为3线;34个T2WI改变频率编码后,双线变为3～4线;所有病例T2WI+STIR图像双线仍然存在。大体以及组织切片上可见死骨、纤维肉芽组织和周围反应性成骨。结论化学位移伪影存在于T1WI及T2WI,且场强越高,越明显。股骨头坏死“双线征”与化学位移伪影无关。更多还原

【Abstract】 Objective To evaluate the features of the double-line sign of femoral head necrosis(FHN)and the chemical shift artifact. Methods MRI images in 130 cases with femoral head necrosis were studied.48 case(s60 hips)with double-line sign in FHN were chosen as the candidates for statistical analysis. TheMR appearance of double line sign was assessed on different sequences to further evaluate the features of thedouble-line sign of osteonecrosis. The MRI of one specimen which was obtained after total replacement of thehip was used to compare with pathological findings. Results 1.5T super conductive imaging unit is moresensitive than 0.5T ones for chemical shift artifact. After performing a reversal of the phase and frequencyencoding directions, the single low signal intensity line turned into three line on T1WI in 20 femoral heads andthe double line turned into three or four high and low signal intensity parallel line on T2WI for 34 ones. Afterperforming suppressive fat images, the double line was remain on T2WI+STIR for 60 hips. ConclusionsChemical shift artifact was existed indeed. It increases proportionally with field strength. Double-line sign inearly FHN is independent of chemical shift artifact.更多还原