正常人膝关节软骨分层的MRI序列选择与优化

目的 选择与优化显示正常人膝关节软骨分层的MRI序列,为关节软骨病变的早期诊断奠定基础.方法 选择无膝关节症状的健康志愿者140例.用1.5T超导型磁共振机,行膝关节矢状面扫描.采用脂肪抑制二维快速小角度激发序列、自旋回波序列T1加权像和脂肪抑制三维稳态旋进快速成像序列3个扫描序列,FLASH和SE序列扫描层厚3 mm, FISP序列扫描层厚1.5 mm.观察膝关节软骨的分层表现,选择出显示软骨分层的最佳MRI序列.结果 FLASH序列140例中有129例分3层,9例无分层,2例分5层,分层清楚,扫描时间较短; SE序列140例中有101例分3层,39例无分层;FISP序列140例中有133例分3层,5例无分层,2例分5层,显示分层模糊,扫描时间长.结论 脂肪抑制二维快速小角度激发序列是显示膝关节软骨分层的最佳序列.

SELECTION AND OPTIMIZATION OF THE MRI SEQUENCE OF THE ARTICULAR CARTILAGE LAYERS IN THE NORMAL KNEES

Objective To select and optimize the MR sequence for showing layer of articular cartilage in the normal knees,which will be the basis for early diagnosis of articular cartilage lesions.Methods One hundred and forty normal knees were studied using a 1.5 Tesla ultraconduct magnetic ransonance unit.All knees were detected through saggittal section,with fat-saturated two-dimensional fast low angle shot(FS-2D-FLASH),spin echo T1-weighted image(SE-T1WI)and fat-saturated three-dimensional fast imaging with steady-state precession(FS-3D-FISP)scan sequences.In FLASH and SE sequences,3 mm thickness was applied.In FISP sequence,1.5 mm thickness applied.The MR appearance of the articular cartilage layers was studied and the best sequence selected.Results In FLASH sequence imaging,129 of 140 with 3 layers appearance,9 of them with 1 layer appearance,2 of them with 5 layers appearance were seen.The layer imaging is clear and the scaning time is shorter.In SE sequence imaging,101 of 140 with 3 layers appearance,39 of them with 1 layer appearance could be seen.Layering appearance was found in less case with SE sequence.In FISP sequence imaging,133 of 140 with 3 layers appearance,5 of them with 1 layer appearance,2 of them with 5 layers appearance could be seen,but the layer image was not clear enough and the scaning time was longer.Conclusion FS-2D-FLASH sequence is the best sequence for imaging of the articular cartilage of the knee jiont.