目的比较正常膝关节软骨MRIT1ρ和三维抑脂扰相梯度回波（3D-FS-SPGR）序列表现,研究T1ρ序列应用于软骨评估的可行性;评估软骨深层与浅层MRIT1ρ值的差异。方法选择经临床和影像确认的26例成年志愿者,其中男性11例,女性15例;年龄15~65岁,平均年龄31.69岁。分析其T1ρ和3D-FS-SPGR序列MRI成像表现。将膝关节软骨划分为髌软骨、髁间窝、股骨内外侧髁、胫骨内外侧平台6个部分。测量相同层面与位置的T1ρ第一回波和3D-FS-SPGR图像上软骨、软骨下骨、背景噪声的信号强度,比较两者的软骨与软骨下骨对比度比（CNR）和软骨信噪比（SNR）。选取6个部位软骨最厚处,把该处软骨厚度等分为深层和浅层,分别测量同像素感兴趣区（ROI）的T1ρ值。对以上数据进行配对t检验,以P〈0.05为差异有统计学意义。结果①膝关节T1ρ序列第一回波图像上的CNR均值和SNR均值均高于同一部位的3D-FSSPGR序列,CNR 29.88±10.00 vs 12.08±3.08（t=23.09,P=0.000）,SNR 34.70±11.16 vs 14.18±3.46（t=23.929,P=0.000）;②正常膝关节软骨深层均值（29.12±8.07）ms,浅层均值（43.23±6.78）ms,浅层T1ρ值显著高于深层表现（t=-24.687,P=0.000）。结论 T1ρ序列可用于软骨临床评估,浅层软骨胶原纤维排列较深层更为致密。
Background The imaging evaluation of pain in patients who have had a hip arthroplasty （HA） is challenging,and traditional imaging techniques,including magnetic resonance imaging （MRI） and computerized tomography （CT）,are limited by metallic artifact.The purpose of the present study was to investigate the use of modified MRI techniques to visualize periprosthetic soft tissues and the bone-implant interface,and to evaluate the value of MRI for the assessment of patients with painful hip arthroplasty.Methods Fifty-six painful hips in fifty-six patients following primary HA were assessed using optimized MRI,CT and standardized radiographs.The diagnosis of MRI was correlated with intraoperative findings as well as with microbiological and histological examinations （when available）.The sensitivity and the specificity of MRI diagnosis were determined according to final diagnosis.The chi-square test was performed to detect a difference between MRI and final diagnosis.Results Forty-eight patients have received revision surgery and final diagnosis were established.MRI was demonstrated high sensitivity and specificity in detecting aseptic loosening （93％ and 95％）,periprosthetic infection （94％ and 97％）,adverse local tissue reaction （100％ and 100％） and periprosthetic fracture （100％ and 100％）.MRI was determined to be the most sensitive technique in detecting implant loosening for any reason,with a sensitivity of 93.8％ for acetabular shell and 97.1％ for femoral stem,compared to 81.3％ and 80.0％ on CT,75.0％ and 77.1％ on radiographs.Conclusions Optimized MRI was effective for the assessment of the periprosthetic soft tissues and bone.The use of modified magnetic resonance imaging parameters provided a useful adjunct to conventional examinations for the evaluation of patients with painful hip arthroplasty.
He ChuanLu YongJiang MeihuaFeng JianminWang YiLiu Zhihong
