Tkach J A, Lin W, Duda J J, Haacke E M, Masaryk T J
Department of Radiology, Cleveland Clinic Foundation, OH 44106.
Radiology. 1994 Jun;191(3):805-11. doi: 10.1148/radiology.191.3.8184069.
To implement and evaluate a variable repetition time (TR) modification of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography.
Variable- and constant-TR 3D TOF MR angiography of the intracranial vasculature was performed in 20 healthy volunteers and 10 patients with known or suspected cerebrovascular disease. Total acquisition time was short and held constant for all studies. Frequency-selective fat saturation (FS) and magnetization transfer saturation (MTS) pulses were applied. The associated maximum-intensity projection (MIP) images were evaluated quantitatively for contrast-to-noise (C/N) and qualitatively for depiction of vessels that exhibit slow flow.
Variable-TR MIP images exhibited improved C/N and depiction of small peripheral vessels and venous structures when compared with constant-TR MIP images. These observations were consistent for all studies.
The variable-TR modification improved the depiction of intracranial vessels that exhibit slow flow.
实施并评估三维（3D）时间飞跃（TOF）磁共振（MR）血管造影的可变重复时间（TR）修改技术。
对20名健康志愿者和10名已知或疑似脑血管疾病患者进行了颅内血管的可变TR和恒定TR 3D TOF MR血管造影。所有研究的总采集时间较短且保持恒定。应用了频率选择性脂肪饱和（FS）和磁化传递饱和（MTS）脉冲。对相关的最大强度投影（MIP）图像进行了对比度噪声（C/N）的定量评估以及对显示缓慢血流的血管描绘的定性评估。
与恒定TR MIP图像相比，可变TR MIP图像在对比度噪声和小周边血管及静脉结构的描绘方面有所改善。所有研究的这些观察结果都是一致的。
可变TR修改技术改善了对显示缓慢血流的颅内血管的描绘。
