严重急性呼吸综合征糖皮质激素治疗后膝关节骨坏死的MRI评价

MRI evaluation of osteonecrosis in knee joints after intravenous administration of corticosteroids in patients with severe acute respiratory syndrome

目的分析严重急性呼吸综合征(SARS)糖皮质激素治疗后膝关节骨缺血性坏死的发生和MRI特点。方法4所医院感染SARS并经糖皮质激素治疗的医护人员共18例,均行双侧膝关节和双髋关节MR检查,确定骨坏死发生与否、病变特点及其与糖皮质激素用量的关系。结果18例中,11例出现膝关节骨坏死,3例合并双侧髋关节股骨头坏死。7例为双侧膝关节骨坏死,4例为单侧。膝关节骨坏死病灶共计38个,34个位于股骨内、外侧髁以及相邻的股骨干,4个位于胫骨内或外侧髁。膝关节骨坏死的大、中病灶多为不规则形,周边呈细带状低信号,其中4个在T2WI上可见“双边征”;坏死灶内T1WI多为等或稍低信号,T2WI多为高、等或混杂信号。小病灶在T1WI上为低信号,T2WI上多为低或高信号。髋关节股骨头坏死灶位于其中上部、软骨下,呈类椭圆形异常信号,病灶内T1WI为等信号,T2WI为高或混杂信号;周边有不规则低信号带,其中1例双侧病灶T2WI上可见“双边征”。结论该组SARS病例糖皮质激素治疗后骨缺血性坏死以膝关节为多,对这类病人应注意早期行膝关节MR检查。膝关节坏死以股骨内、外侧髁和相邻的股骨干最多见,胫骨内外、侧髁亦可发生。骨缺血性坏死的发生及严重程度与静脉糖皮质激素用量有关。

Objective To evaluate MRI features of osteonecrosis in knee joints after intravenous administration of exogenous corticosteroids in patients with severe acute respiratory syndrome （SARS）.Methods MRI was done in 18 patients （ medical staff from 4 hospitals ） suffered from SARS and treated with intravenous use of exogenous corticosteroids in hip joints and knee joints to indicate the findings and characteristics of osteonecrosis as well as their relation with hormone amount. Results Eleven patients showed lesions of osteonecrosis in knee joints with bilateral in 7 and unilateral in 4, and 3 patients were complicated with avascular necrosis in bilateral femoral heads. Among the 38 lesions in knee joints,34 lesions were located in medial condylu, lateral condylus and shaft of femur,and 4 in medial condylus or lateral condylus of tibia. Large-middle lesions showed geographic focus of typically heterogeneous signal （ low or intermediate signal intensity on T1WI and high or intermediate signal intensity T2WI） within the marrow that was surrounded by characteristic low signal intensity, serpentine border on T1, T2WI. This border showed a classic double-line sign on T2WI in 4 lesions. Small lesions showed low signal intensity on T1 and low or high signal intensity on T2WI. Subchondral avascular necrosis in middle-upper femoral heads showed intermediate signal intensity on T2 weighted images and high or complicated signal intensity on T2WI encircled with characteristic low signal intensity, serpentine border on T1 and T2WI. This border showed a classic double-line sign on T2 weighted images in avascular necrosis of bilateral femoral heads in 1 case.Conclusion In these cases, osteonecrosis in knee joints was more than in femoral heads in patients with SARS after intravenous use of exogenous corticosteroids, mostly located in medial condylus, lateral condylus and shaft of femur as well as in medial condylus or lateral condylus of tibia. So, MRI should be early done in these patients in knee joints. Degree of osteonecrosis was associated with amount of intravenous use of exogenous corticosteroids.