基于MRI、CT不同层面和位像形态学依据回顾性分析双侧股骨头坏死塌陷的危险因素

Risk factors for collapse in patients with osteonecrosis of bilateral femoral heads:Retrospective analysis based on MRI and CT

背景：MRI、CT对骨组织形态学变化评估为客观金标准。目的；基于MRI、CT不同位像影像学客观依据分析双侧股骨头坏死塌陷的危险因素。设计、时间及地点：自身对照，分类汇总分析，试验于2003-04／2007-06在北京协和医学院研究生院完成。参试者：选择本科收治的双侧股骨头坏死并有完整塌陷前，未塌陷资料的患者48例，男21例，年龄21～48岁：女27例，年龄23～46岁。均为激素性股骨头坏死。股骨头坏死按照国际骨循环学会（ARCO）标准分期，ARCOA-C4例，ARCOB-C4例，ARCOB-B12例，ARCOC-C28例。方法：对有单/双侧塌陷的双侧股骨头坏死的患者影像资料进行回顾性分析。根据早期MRI T1中低信号带的形态分为开放型和包含型。根据坏死灶的CT变化类型分为：a：坏死灶形成硬化带，并且在软骨下骨下为连续的硬化带；b：在软骨下骨下为不连续的硬化带：c：软骨下骨下硬化带形成不明显；d：没有明显硬化带形成，坏死灶呈均匀中密度影。主要观察指标：坏死灶大小、位置、MRI形态、CT形态及塌陷。结果：单侧塌陷43例（ARCOA-C4髋．ARCOB-C4髋．ARCOB-B12髋，ARCOC-C23髋），双侧塌陷5例（ARCOC-C10髋）。负重面外侧型（64髋）塌陷49髋（ⅡB12髋．ⅡC37髋）．负重面中央型（21髋）塌陷4髋（ⅡC4髋）负重面内侧型（11髋）无塌陷：早期MRI T1中低信号带的形态开放型塌陷51髋，闭合型塌陷2髋。CT示坏死灶形成硬化带，并且在软骨下骨下为连续的硬化带0／23（type-a）：有不连续硬化带形成但没有延伸到软骨下骨下者塌陷19／30髋（type-b）；CT有硬化带形成，并不连续延伸到软骨下骨下者塌陷28／37髋（type-c）：没有硬化带形成．病灶呈均匀中高密度影者塌陷6／6髋（type-d）。结论：以MRI、CT评估，坏死灶上负重面外侧型更易早塌陷；对于双侧股骨头坏死的病例，MRI显示相似的面积，T1低信号带包含型者，预后相对较好；CT显示软骨下骨均匀增厚或明显的“焊接”现象是延迟塌陷的因素：但是软骨下骨没有或有不均匀不连续性硬化是危险因素。

BACKGROUND： MRI and CT assessments are golden standards for bone histomorphological changes. OBJECTIVE： To explore the risk factors for the osteonecrosis and collapse of bilateral femoral heads based on MRI and CT imaging. DESIGN, TIME AND SETTING： The self-control and summary were performed at Department of Graduate, Peking Union Medical College from April 2003 to June 2007. PARTICIPANTS： Forty-eight patients with osteonecrosis of bilateral femoral heads but no collapse before osteonecrosis were selected from Department of Graduate, Peking Union Medical College, including 21 males aged 21-48 years, and 27 females aged 23 46 years. The osteonecrosis was caused by hormone. The patients were classified according to the criteria of Association Research Circulation Osseous （ARCO）： 4 cases of ARCOA-C, 4 of ARCOB-C, 12 of ARCOB-B and 28 of ARCOC-C. METHODS： The data of patients with osteonecrosis of femoral head with unilateral or bilateral collapse were retrospectively analyzed. According to the shape of low signal band on coronal section of procollapse MRIT1, the osteonecrosis of femoral head was classified into open type and contained type; According to the imaging changes on CT, 4 types of osteonecrosis were found in lesions： a. there was sclerotic band around the necrotic lesion, moreover, a continuous sclerotic band formed beneath subchondral bone; b. there was an discontinued sclerotic band beneath subchondral bone; c. there was no obvious sclerotic band beneath subchondral bone, d. there was no sclerotic band around osteonecrotic lesion. MAIN OUTCOME MEASURES： Size, location, MRI and CT appearance of lesions and collapse. RESULTS： In all the patients with osteonecrosis of the femoral head, 43 cases （ARCOA-C 4 hips, ARCOB-C 4 hips, ARCOB-B 12 hips, and ARCOC-C 23 hips） were affected with unilateral collapse and 5 （ARCOC-C 10 hips） were bilateral collapse; 49 femoral heads （ARCO-B 12 hips, ARCO-C 37 hips） had lateral collapse; 4 femoral heads （ARCO-C 4 hips） had centrel type collapse, and 11 hips had no collapse. According to the shape of low signal band on coronal section of procollapse MRIT1, 51 hips had open collapse and 2 hips had contained type collapse. According to the classification on CT, there were 0/23 hips with type-a, 19/30 with type-b, 27/38 with type-c and 6/6 with type-d. CONCLUSION： Lateral collapse is more common based on MRI and CT assessments. For cases of osteonecrosis of the bilateral femoral heads, those of contained type with low signal band on TI show a prognosis if the size of lesions is similar on MRI. Thickness or obvious welding is risk factor for delayed collapse. No or discontinued sclerotic band beneath subchondral bone on CT is other risk factor for collapse.