Isoda H, Ramsey R G, Takehara Y, Takahashi M, Kaneko M
Department of Radiology, Hamamatsu University School of Medicine, Japan.
AJNR Am J Neuroradiol. 1997 Sep;18(8):1463-72.
To investigate the signal intensity of lateral and terminal saccular aneurysm models with differing neck sizes using three-dimensional time-of-flight (TOF) MR angiography with various imaging parameters.
The study included four lateral and four terminal saccular aneurysm models with pulsatile flow. The height and fundus diameter were 10 mm; the neck diameters were 2.5 mm, 5 mm, 7.5 mm, and 10 mm, respectively. Each aneurysm model was examined with fast imaging with steady-state precession MR sequences with parameters of 20-140/7 (repetition time/echo time) and flip angles of 10 degrees to 30 degrees. Signal intensity was measured and compared among the models.
Three-dimensional TOF MR angiography with the shorter repetition time and/or larger flip angle showed weaker signal intensity in the aneurysm models. Stronger signal intensity was obtained in the terminal saccular aneurysm models and/or the models with a wider neck than in the lateral saccular aneurysm models and/or the models with a narrower neck. In some aneurysm models, longer repetition times produced greater signal intensity than that of background brain models, but not in aneurysms with narrow necks.
Noncontrast 3-D TOF MR angiography delineated terminal saccular aneurysms and/or aneurysms with wider necks and did not delineate lateral saccular aneurysms and/or aneurysms with narrower necks. Longer repetition times are recommended to allow the spins flowing into the aneurysms to recover.
使用具有不同成像参数的三维时间飞跃（TOF）磁共振血管造影术，研究不同颈部大小的外侧和终末囊状动脉瘤模型的信号强度。
该研究包括四个具有搏动血流的外侧囊状动脉瘤模型和四个终末囊状动脉瘤模型。高度和瘤底直径均为10毫米；颈部直径分别为2.5毫米、5毫米、7.5毫米和10毫米。每个动脉瘤模型均采用稳态进动快速成像磁共振序列进行检查，参数为20 - 140/7（重复时间/回波时间），翻转角为10度至30度。测量并比较各模型之间的信号强度。
具有较短重复时间和/或较大翻转角的三维TOF磁共振血管造影在动脉瘤模型中显示出较弱的信号强度。终末囊状动脉瘤模型和/或颈部较宽的模型比外侧囊状动脉瘤模型和/或颈部较窄的模型获得更强的信号强度。在一些动脉瘤模型中，较长的重复时间产生的信号强度高于背景脑模型，但在颈部狭窄的动脉瘤中并非如此。
非对比增强三维TOF磁共振血管造影可描绘终末囊状动脉瘤和/或颈部较宽的动脉瘤，而无法描绘外侧囊状动脉瘤和/或颈部较窄的动脉瘤。建议使用较长的重复时间以使流入动脉瘤的自旋恢复。
