小孔径正交相控阵小动物实验线圈磁共振成像质量研究

目的 比较小孔径正交相控阵小动物实验线圈与C3表面线圈在大鼠头部磁共振成像(MRI)检查的成像质量.方法 将10只雄性SD大鼠分别应用2种线圈进行头部MRI检查.测量大脑皮层、小脑、脑干、肌肉及眼球内的房水等部位的信号强度及背景噪声值,计算信噪比(SNR);由2位放射科医生对图像质量进行评分,将测量数据进行统计分析.结果 所有图像均得到了大脑皮层、小脑、脑干、肌肉及眼球内的房水等部位的SNR值.两种线罔成像质量比较,大脑皮层T1WI横断位(SNRsense-body=41.3±23.5;SNR C3=10.3±0.5;t=-3.21)、T2WI矢状位(SNR sense-body=63.8±16.6;SNR C3=37.9±4.4:t=-4.00)以及T2WI冠状位(SNR sense.body=91.6±23.8;SNR C3=38.5±11.8;t=-5.69)图像SNR差异均有统计学意义(P＜0.01);且在小脑、脑干以及眼球房水测量的结果亦相仿;肌肉组织仅在T1WI横断位(SNR sense-body=39.9±21.1;SNR C3=8.3±1.7;t=-3.64)和T2WI冠状位(SNR sense-body=23.5±9.8:SNR C3=11.9±4.1;t=-3.10)的SNR差异有统计学意义(P＜0.01).采用小孔径正交相控阵线圈检查获得的图像中T2WI冠状面得分最高,而2种线圈检查获得的弥散加权成像(DWI)图像质量评分均最低.结论 在大鼠头部成像MRI检查中,小孔径正交相控阵小动物实验线圈的信噪比和图像质量优于现在经常应用的C3表面线圈.

Imaging quality of small aperture orthogonal phased-array coil in MRI: a creatural experiment

Objective To compare the rat head MRI image quality of small aperture orthogonal phased-array creatural experimental coil and the C3 surface coil.Methods Ten male SD rats underwent both coils for head MRI.The signal intensities and background noise values of the cerebral cortex,cerebellum, brain stem, muscle and aqueous humor in eye were measured, and signal to noise ratio (SNR)was calculated.Image quality scores were obtained from 2 radiologists, t test was performed for statistical differences.Results SNR values over the cerebral cortex, cerebellum, brain stem, muscle and aqueous humor in eye were obtained from the images of all protocols.Statistically significant differences of the two coils were achieved in the cerebral cortex in the transverse T1WI (SNR sense-body=41.3±23.5; SNR C3=10.3±0.5; t=-3.21), sagittal T2WI (SNR sense-body=63.8±16.6; SNR C3=37.9±4.4; (=-4.00) and coronal T2WI (SNR sense-body=91.6±23.8, SNR C3=38.5±11.8; t=-5.69)(P＜0.01), so were in cerebellum, brain stem and aqueous humor in eye.Statistical differences of muscular tissue were observed merely in the transverse axial TiWI (SNR sense-body=39.9±21.1; SNR C3=8.3±1.7; t=-3.64) and the coronal T2WI (SNR sense-body=23.5±9.8; SNR C3=1 1.9±4.1; t=-3.10)(P＜0.01).Coronal T2WI score achieved the top in the small aperture orthogonal phased array coil, and the image qualities of diffusion-weighted imaging(DWI)in both two coils were low.Conclusion In head MRI of rats, the SNR value and head image quality of small aperture orthogonal phased-array coil is superior to that of the frequently used C3 surface coil.