Schmalbrock P, Yuan C, Chakeres D W, Kohli J, Pelc N J
GE Medical Systems, Milwaukee.
Radiology. 1990 Jun;175(3):861-5. doi: 10.1148/radiology.175.3.2343137.
Angiographic displays of cerebral vessels can be generated with single-excitation three-dimensional magnetic resonance imaging. Differentiation of true stenosis from artifactual signal loss, due to dephasing effects from fast or nonconstant blood flow and field inhomogeneities, poses a significant clinical problem that can be largely resolved with the use of very short echo times (TEs). A three-dimensional imaging technique was developed that allows TEs of 3.1 msec without and 4.5 msec with first-order flow compensation gradients. The short TEs were achieved with short asymmetric radio-frequency pulses, gradients of minimal duration, and fractional echoes. Significantly improved images of normal tortuous vessels with fast flow were obtained. With this method, accuracy in depicting the vessel lumen and confidence in the findings were markedly increased.
脑血管造影显示可通过单次激发三维磁共振成像生成。由于快速或非恒定血流及场不均匀性的去相位效应导致的真实狭窄与伪影信号丢失的区分，是一个重大临床问题，使用极短回波时间（TE）可在很大程度上解决该问题。开发了一种三维成像技术，该技术在无一阶流动补偿梯度时允许TE为3.1毫秒，有一阶流动补偿梯度时允许TE为4.5毫秒。通过短的非对称射频脉冲、最短持续时间的梯度和分数回波实现了短TE。获得了快速血流情况下正常迂曲血管的显著改善图像。使用该方法，描绘血管腔的准确性和对结果的信心显著提高。
