Scarabino T, Carriero A, Giannatempo G M, Simeone A, Armillotta M, Bonomo L, Salvolini U
Dipartimento di Diagnostica per immagini, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, FG.
Radiol Med. 1997 Oct;94(4):325-8.
A new noninvasive technique, dynamic Magnetic Resonance Angiography (MRA) during rapid infusion of paramagnetic contrast medium, has been recently developed for the study of neck vessels. This study was carried out to optimize technical parameters.
Twenty healthy volunteers (10 men and 10 women; age range: 25 to 50 years) were examined with a 1.5 T MR unit equipped with fast imaging software and a dedicated coil. Dynamic MRA was performed using fast spoiled gradient recalled (fast SPGR) sequences acquired on the coronal plane 13 s after contrast medium injection. Imaging parameters were: Echo Time (TE): 1 ms, Repetition Time (TR): 8 ms, flip angle: 60 degrees, matrix 256 x 128, number of excitations: 1, field of view: 18 x 13 cm, number of partitions per slab: 28, slice thickness: 1 mm, acquisition time: 32 s. A dose of .2 mmol/kg of paramagnetic contrast medium was administered with an MR compatible automatic injector, at a speed rate of 1.5 ml/s. Angiographic images were postprocessed with the maximum intensity projection (MIP) and targeted MIP algorithms.
Using the above parameters and rapid contrast medium injection, the carotid arteries on the coronal plane (including the vessels from the proximal aspect of the common carotid arteries to the intracranial tract of the internal carotid arteries) in 18 cases. In the other two cases the tortuosity and the position of the carotid arteries on two different planes, prevented their complete visualization. The vertebral arteries were completely demonstrated in 50% of the investigated population. Partial or total overlapping of jugular veins did not affect the recognition of the carotid vessels in 10 cases, also with targeted MIP postprocessing.
The vascular semiology of dynamic gadolinium enhanced MRA seems to be closer to that of conventional angiography than of conventional MRA, likely due to the same modality of vessel depiction, based on contrast medium administration. Flow artifacts, the major pitfall of conventional MRA causing signal void and overestimation of stenosis grade, are not frequent in dynamic MRA.
Gadolinium enhanced dynamic MRA ensures panoramic and high resolution angiographic-like depiction of the neck vessels, providing rapid and excellent definition of vascular morphology. Thus dynamic MRA appears to be a substantial alternative to conventional MRA and conventional angiography.
一种新的无创技术，即快速注入顺磁性造影剂期间的动态磁共振血管造影（MRA），最近已被开发用于颈部血管的研究。本研究旨在优化技术参数。
20名健康志愿者（10名男性和10名女性；年龄范围：25至50岁）使用配备快速成像软件和专用线圈的1.5T磁共振设备进行检查。动态MRA使用快速扰相梯度回波（fast SPGR）序列在注入造影剂13秒后于冠状面采集。成像参数为：回波时间（TE）：1毫秒，重复时间（TR）：8毫秒，翻转角：60度，矩阵256×128，激励次数：1，视野：18×13厘米，每层板的分区数：28，层厚：1毫米，采集时间：32秒。以1.5毫升/秒的速度用磁共振兼容自动注射器注入剂量为0.2毫摩尔/千克的顺磁性造影剂。血管造影图像采用最大强度投影（MIP）和靶向MIP算法进行后处理。
使用上述参数并快速注入造影剂，18例在冠状面上显示了颈动脉（包括从颈总动脉近端到颈内动脉颅内段的血管）。在另外两例中，颈动脉在两个不同平面上的迂曲和位置妨碍了它们的完整显示。在50%的受调查人群中椎动脉得到了完整显示。在10例中，即使采用靶向MIP后处理，颈静脉的部分或完全重叠也未影响颈动脉的识别。
动态钆增强MRA的血管影像学表现似乎比传统MRA更接近传统血管造影，这可能是由于基于造影剂注入的血管描绘方式相同。流动伪影是传统MRA的主要缺陷，会导致信号缺失和狭窄程度高估，在动态MRA中并不常见。
钆增强动态MRA可确保对颈部血管进行全景式和高分辨率的血管造影样描绘，能快速且出色地显示血管形态。因此，动态MRA似乎是传统MRA和传统血管造影的一种重要替代方法。
