磁共振成像三种增强序列对骨和软组织病变增强效果的比较研究

Comparative study of 3 kinds of enhanced sequences of MRI system on the enhanced effects of the lesions of bone and soft tissue

目的:比较研究磁共振成像(MRI)系统的T1快速自旋回波(T1FSE)序列、T1三点法非对称回波水脂分离成像(T1IDEAL)序列及T1容积加速肝脏采集(T1LAVA-Flex)序列3种增强序列成像在骨和软组织病变中的增强效能,以提高四肢软组织MRI增强的质量和效率。方法:选取在医院就诊的31例行骨盆及下肢软组织MRI检查的患者,按照随机数表法将每例患者在平扫的基础上同时予以T_(1) FSE、T_(1) IDEA和LAVA-Flex增强序列检查的结果分别纳入T_(1) FSE组、T_(1) IDEA组和LAVA-Flex组,比较3组图像的信噪比(SNR)、对比噪声比(CNR)、背景信号的标准差(SD)、病灶边缘的清晰度及伪影评分。采用单因素方差分析方法和LSD两两比较的方法比较3组序列的增强效能,并进行图像清晰度及伪影评分比较。结果:3组中的31例患者T1FSE、T1IDEAL和T1LAVA-Flex序列增强图像的SNR、CNR和SD比较,T1IDEAL组SNR、CNR和SD最佳,其余依次为T1FSE组、T1LAVA-Flex组,3组SNR、CNR和SD的比较差异有统计学意义(F=59.759,F=5.362,F=109.33;P<0.05)。T1FSE组和T1IDEAL组图像显示病灶边缘清晰度均优于T1LAVA-Flex组,差异有统计学意义(χ^(2)=7.939,χ^(2)=5.429;P<0.05);但伪影T1IDEAL组和T1LAVA-Flex组高于T1FSE组,3组比较差异有统计学意义(χ^(2)=5.905,P<0.05)。结论:T1IDEAL增强序列成像在骨与软组织病变中具有最高的SNR、CNR和清晰度,以及较少的伪影,可作为骨及软组织病变增强扫描的首选序列,T1 FSE可以做为基本的增强序列,T_(1) LAVA-Flex增强序列可降低增强扫描的时间。

Objective: To compare and study the enhanced effects of T1 fast spin-echo(T1 FSE) enhanced sequence,T1 three-point asymmetric echo water-lipid separation imaging(T1 IDEAL) enhanced sequence, and T1 liver volume accelerated acquisition(T1 LAVA-Flex+C) enhanced sequence of magnetic resonance imaging(MRI) system on the lesions of bone and soft tissue, so as to improve the quality and efficiency of MRI enhancement for soft tissues of extremities. Methods: A total of 31 patients who admitted to hospital and underwent MRI examination of pelvic and lower soft tissue were selected. The results of patients who underwent enhanced sequence examinations of T1 FSE, T1IDEA and LAVA-Flex on the basis of plain scan were divided into T1 FSE group, T1 IDEA group and LAVA-Flex group according to random number table method. The signal-to-noise ratio(SNR), contrast noise ratio(CNR), standard deviation(SD) of background signal, sharpness and artifact score of focal edge of the three groups of images were compared. One-way analysis of variance and least significant difference(LSD) comparison between any two means were used to compare the enhanced efficiency, as well as the sharpness and artifact score of images, of the three groups of sequences. Results: The compared results of SNR, CNR and SD of enhanced images of T1 FSE, T1 IDEAL and T1LAVA-Flex sequence of 31 patients in three groups indicated that the results of SNR, CNR and SD of T1 IDEAL group were best, and then, the successive groups were T1 FSE group and T1 LAVA-Flex group, and the differences of SNR,CNR and SD among three groups were significant(F=59.759, F=5.362, F=109.33, P<0.05). The sharpness of focal edge of T1FSE group and T1IDEAL group were respectively better than that of T1 LAVA-Flex group, and the differences were statistically significant(x~2=7.939, x~2=5.429, P<0.05), but the artifact of T1 IDEAL group and T1 LAVA-Flex group were significantly higher than that of T1 FSE group and the difference of that among three group was significant(x~2=5.905, P<0.05). Conclusions: T1 IDEAL enhanced sequence imaging has the highest SNR and CNR, and has favorable sharpness and fewer artifacts in the lesions of bone and soft tissue, which can be used as the preferred sequence for the enhanced scan on the lesions of bone and soft tissue. T1 FSE can be used as the basic enhanced sequence, and T1 LAVA-Flex enhanced sequence can reduce the time of enhanced scan.