磁共振关节软骨成像的不同序列信号比较

Comparison of cartilage signal intensity in different magnetic resonance imaging

目的:通过比较软骨信号噪声比(SNR)和对比度噪声比(CNR),分析临床常用的磁共振(MR)序列显示关节软骨的能力与限度。方法:选取12例成人离体膝关节标本行软骨磁共振成像(MRI)。应用的MR序列包括:①自旋回波T1加权序列(SE T1W);②快速自旋回波T2加权序列(FSE T2W);③短T1翻转恢复序列(STIR);④脂肪抑制质子密度序列(FS-PD);⑤三维脂肪抑制扰相梯度回波序列(3D-FS-SPGR);⑥重度T2加权梯度回波序列(T2*W GRE)。在股骨髁间凹中央层面上分别测量股骨髁软骨、股骨干骺端骨髓、小腿腓肠肌和背景噪声信号强度(SI),计算软骨SNR和软骨-关节液、软骨-骨髓、软骨-肌肉CNR。结果:3D-FS-SPGR和FS-PD序列软骨SNR最高(P<0.001);3D-FS-SPGR序列的软骨/骨髓CNR最高(P=0.0123);3D-FS-SPGR和FS-PD序列的软骨/滑液、软骨/肌肉CNR高于其他序列(P<0.001)。结论:在目前临床应用的序列中,3D-FS-SPGR和FS-PD序列是进行软骨MRI的理想序列组合。

Objective To investigate the ability and limitation of clinical cartilage magnetic resonance imaging （MRI） through signal-noise ratio （SNR） and contrast-noise ratio （CNR） analysis. Methods SE T1W, FSE T2W, STIR, FS-PD, 3D-FS-SPGR and T2^＊W GRE imaging were performed in 12 adult cadaveric knees with GE Signal 1 .ST unit. The signal intensity （SI） of the cartilage in femoral condyle, femoral metaphysic ossium, gastrocnemius and background noise was measured in the imaging located in femoral condyle fossa. Then the cartilage SNR and CNR between cartilage and medulla ossium, synovia and myoideum were calculated. Results The cartilage SNR in 3D-FS-SPGR and FS-PD imaging was higher than the values in the other sequences （P〈0.001）; the cartilage / medulla ossium CNR in 3D-FS-SPGR imaging was the highest in all the MR sequences （P=0.0123）; the cartilage/synovia CNR and the cartilage/myoideum CNR in 3D-FS- SPGR and FS-PD imaging were higher than the values in the other sequences （P〈0.001）. Conclusions 3D-FS-SPGR and FS-PD imaging are the optimal sequences for articular cartilage MR1.