骨梗死影像学表现及其病理学基础

目的 探讨骨梗死的影像学表现及其病理学基础。方法 回顾性分析对临床随访及穿刺活检病理证实的11例骨梗死X线平片、CT及MRI征象，并结合骨梗死早、中晚期病理改变，总结其影像学特征。结果 病变主要累及股骨下端和胫骨上端。骨梗死早期X线、CT阴性或仅局部骨小梁模糊，MRI表现为骨梗死灶中心区呈等至短T1、T2信号改变，周边环绕花边状长T1、长T2信号带，示梗死灶内出血肿胀，与正常骨髓间有充血水肿;中晚期X线、CT表现为斑片状、条索状及不规则骨质硬化和钙化;MRI表现为病变中心等或稍长T1、T2信号改变;病灶边缘T1WI呈花边状低信号带，T2WI呈内层为高信号、外层为低信号的双信号带。最后MRI呈长T1、短T2信号影，示坏死组织被肉芽组织和纤维组织替代而发生纤维化和钙化或骨化。结论 骨梗死的各期有不同的影像学表现和相应的病理学基础，MRI发现早期病变较平片和CT敏感，中晚期平片、CT和MRI均具有特征性表现，而MRI是本病最好的检查手段。

Pathological basis and imaging findings of bone infarction

Objective To explore the imaging manifestations and their related pathological basis of bone infarction.. Methods The plain radiography, CT and MRI images of eleven cases of bone infarction which were confirmed by pathological puncture biopsy and clinical follow up visit were analyzed retrospectively. Their image features were summarized with their pathological changes of early, middle and late stages. Results Most of the infarction sites were distal femur and proximal tibia. In early stage, the major image findings of plain radiography and CT were negative or only a slight dim of local bone trabecula, and the major MRI manifestations were iso/short T1/T2 signal changes in the center of the foci and lace-like long T1/T2 signal zone around the foci, reflecting edema and hemorrhage within the infarction, and congestive edema between the foci and normal marrow. In the late stage of the infarction, the major image changes of plain radiography and CT were patching, trabs and irregular shaped punctate calcifications, the major MRI manifestations were iso/long T1/T2 signal changes in the center of the foci and appearance of lace-like low T1WI signal zone around the foci, two layers of T2WI signal zone which was low at out layer and high at inner layer was also observed. Another MRI manifestation was long T1 and short T2 signals, reflecting that the necrotic tissue were replaced by granulation tissue and fibrous tissue, and a fibrosis and calcification/ossification process occurred. Conclusion The imaging features of bone infarction and their related pathological basis are different at different stages. In early stage, MRI is more effective to the diagnosis of bone infarction than plain radiography and CT, in middle and late stage, plain radiography, CT and MRI have their distinctive manifestations respectively, but MRI is the best way to examine and detect bone infarction.