骨梗死的影像学表现及其病理基础

目的探讨骨梗死的影像学表现及其相应的病理基础. 资料与方法对14例累及29个骨骼的骨梗死患者行X线、CT及MRI检查,分析其影像学表现,并将骨梗死分为急性期、亚急性期和慢性期,观察其病理改变. 结果骨梗死病变急性期X线、CT扫描表现为干骺端骨质疏松,MR T1WI呈等至高信号,T2WI呈高信号,示梗死灶内出血肿胀,周围见规则低信号环,与正常骨髓间有线状T1低信号、T2高信号,示反应性新骨形成和周围充血水肿;亚急性期X线、CT扫描表现为小的虫噬样改变,伴有斑点状硬化,MR T1WI呈等或稍低信号,T2WI呈等或稍高信号,周围见低信号带,与正常骨髓间有线状T1低信号、T2高信号,示脂肪坏死、反应性新骨形成、纤维化和充血水肿;慢性期X线、CT扫描呈不规则状、蜿蜒状硬化斑块,MR T1WI和T2WI均呈低信号,示坏死组织被肉芽组织和纤维组织替代而发生纤维化和营养不良性钙化或骨化. 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,在急性和亚急性期,MRI优于平片和CT,在慢性期,平片、CT和MRI均具有特征性表现.

Imaging Findings and Pathologic Basis of Bone Infarction

Objective To discuss the imaging features of bone infarction and their pathologic basis.Materials and Methods Radiography, CT and MRI were performed in 14 patients with 29 bone infarctions. The imaging findings were analyzed. Based on the imaging findings, the lesions were classified into acute, subacute and chronic stages. The imaging findings were compared with pathologic results.Results In acute stage, osteoporosis could be seen at metaphysis on plain film and CT scans, which presented as iso-/high-signal on T 1WI and high-signal on T 2WI and was separated from the normal bone marrow with linear T 1 low- signal and T 2 high-signal, reflecting the edema and hemorrhage within the infarction. In subacute stage, the infarction displayed as multiple moth-eaten lytic bony lesions with punctate calcifications on plain film and CT scans. The infarction was manifested as iso- or slight low-signal on T 1WI and iso- or slight high-signal on T 2WI with a low-signal zone around and was separated from the normal marrow with linear T 1 low-signal and T 2 high-signal, reflecting, pathologically, fat necrosis, reactive bone formation, fibrosis and congestive edema. In chronic stage, the lesion was characterized by irregular sclerosis and tortuous calcification on plain film and CT scans, and by low-signal on both T 1WI and T 2WI, indicating the formation of fibrosis and dystrophic calcification due to the replacement of necrotic tissue by granulation and fibrous tissue.Conclusion The imaging manifestations of bone infarction in different stage have corresponding pathologic basis. During acute and subacute stages, MRI is superior to plain film and CT. In chronic stage, the lesion shows certain characteristic signs on plain film, CT or MRI.