WE 3D-FLASH序列对腰椎间关节软骨成像的临床研究

Clinical study on WE 3D-FLASH sequence of magnetic resonance imaging in lumbar zygapophyseal joint cartilage

目的比较水激励三维快速小角度激发成像(WE 3D-FLASH)序列用不同翻转角成像对正常成人腰椎间关节软骨的评价。方法健康成年志愿者12名,用Siemens1.5T超导磁共振成像系统行L4-5右侧椎间关节多方位扫描,扫描序列为不同翻转角的WE 3D-FLASH序列。对各序列扫描获得的12个椎间关节矢状和横断正中层面的关节软骨、骨皮质、骨髓、关节腔及背景的相同位置的信号强度进行测量,分别计算比较不同序列图像软骨SNR值及软骨与骨皮质、软骨与骨髓、软骨与关节腔的CNR值。结果①四种不同翻转角(FA10°、FA 20°、FA 30°、FA 40°)WE 3D-FLASH序列矢状面和横断面图像软骨SNR、软骨-骨皮质CNR和软骨-骨髓CNR的值随翻转角增大而逐渐变小。②WE 3D-FLASH序列矢状面图像均不能显示椎间关节关节腔,横断面图像都能显示关节腔,WE 3D-FLASH(FA 20°)序列横断面图像软骨与关节腔CNR最高,矢状和冠状面图像不能显示关节腔。结论①WE 3D-FLASH序列能清晰显示腰椎间关节软骨,WE 3D-FLASH(FA10°)序列图像软骨信号最高,与骨皮质、骨髓对比度最好,WE 3D-FLASH(FA 20°)序列图像软骨与关节腔的对比度最好。②腰椎间关节横断面MRI图像可显示关节腔,对腰椎间关节软骨的显示优于其它方位图像,推荐横断位为腰椎间关节软骨的首选扫描方位。

【Objective】 To compare water excitation 3-dimensional fast low angle shot imaging（WE 3D-FLASH） sequences with different flip angle（FA） on evaluating normal adult lumbar zygapophyseal joint cartilage imaging.【Methods】 The right L4-5 lumbar zygapophyseal joints of 12 healthy adult volunteers were scanned through sagittal,transverse and coronal planes by Siemens 1.5 T MRI System.The scan sequences were WE 3D-FLASH with different flip angle.Each scan sequence acquisitioned images from the same layer,and then the signal-noise ratio（SNR） for articular cartilage,contrast-noise ratio（CNR） for cartilage versus bone cortex,cartilage versus bone marrow and cartilage versus articular cavity in the sagittal and transverse images were calculated.【Results】 ①Comparison of the 4 flip angle（FA 10°,FA 20°,FA 30°,and FA 40°） WE 3D-FLASH sequences： the values of the cartilage SNR,the CNR of cartilage versus bone cortex and the CNR of cartilage versus bone marrow in sagittal and transverse images became smaller with flip angle increasing.②The articular cavities of the lumbar zygapophyseal joints couldn’t be presented in the sagittal images in WE 3D-FLASH sequences,while,the cavities could be presented in the transverse images in WE 3D-FLASH sequences.The best CNR of cartilage versus articular cavity was found in images in the WE 3D-FLASH（FA 20°） sequence.The cavities of the lumbar zygapophyseal joints could be presented in the transverse images in the WE 3D-FLASH（FA 20°） sequence but couldn′t be displayed in all of the sagittal and coronal images in the WE 3D-FLASH（FA 20°） sequence.【Conclusion】 ①WE 3D-FLASH sequence has better definition of cartilage images,then,the highest cartilage SNR,best CNR of cartilage versus bone cortex,and best CNR of cartilage versus bone marrow were found in the images in the WE 3D-FLASH（FA 10°） sequence,the best CNR of cartilage versus articular cavity was found in the images in WE 3D-FLASH（FA 20°） sequence.②The MRI transverse scanning of the lumbar zygapophyseal joints can show the cavities,and its presentation of the lumbar zygapophyseal joint cartilage is superior to that of the sagittal and coronal scanning,which possibly can serve as the first choice for the lumbar zygapophyseal joint cartilage scanning.