三种TOF法MRA诊断实验性动脉瘤的对比分析

目的：比较分析三种ＴＯＦ法ＭＲＡ的图像质量，以及不同成像技术对动脉瘤的诊断价值。材料与方法：用静脉囊镶嵌法将１８只犬制成三种类型（单侧型、分叉型、末梢型）颈总动脉囊状动脉瘤模型，术后２周分别进行ＩＡＤＳＡ、２ＤＴＯＦ、单层块３ＤＴＯＦ、薄块多层重叠技术（ＭＯＴＳＡ）ＭＲＡ检查。结果：以ＩＡＤＳＡ图像为标准，２ＤＴＯＦ、单层块３ＤＴＯＦ、ＭＯＴＳＡＭＲＡ都能显示动脉瘤的位置、形态、类型、大小、瘤颈、瘤体伸展方向。其中以ＭＯＴＳＡＭＲＡ图像最具评价能力，显示动脉瘤的形态、类型、瘤颈优于２ＤＴＯＦ、单层块３ＤＴＯＦ，不足之处图像有层块梯阶样伪影。三种ＴＯＦ成像技术对动脉瘤内缓慢血流、湍流、血栓、大动脉瘤有不同程度的信号丢失。结论：三种ＴＯＦ法成像技术中，ＭＯＴＳＡ技术最有利于作为临床３ＤＴＯＦ法ＭＲＡ检查颅内动脉瘤的常规成像技术。

MR Angiography in Experimental Aneurysms: Comparison of Three Time-of-Flight Techniques

PURPOSE:To investigate three TOF MRA image quality and diagnostic accuracy in the detection of aneurysms by comparing it with IA DSA. MATERIALS and METHODS:18 canine carotid aneurysms(6 lateral, 6 bifurcation, and 6 terminal )were constructed and examinated with IA DSA, 2D TOF, a single volume 3D TOF, multiple overlapping thin slab acquisition (MOTSA) MRA in the 2nd week after the procedure. RESULTS:On the basis of multiple criteria, three TOF techniques MRA all can detect of location, morphology, type, size, the neck and direction of aneurysms, but no sensitivity of slow flow,turbulent flow and thrombosis intraaneurysms. MOTSA MRA is superior to 2D TOF, a single volume 3D TOF MRA in detection of the neck, morphology, type of aneurysms. But the slab boundary artifact is seen in MOTSA MRA images. CONCLUSION:MOTSA MRA is the most useful TOF technique to the clinician in the evaluation of aneurysms.