Catalano C, Laghi A, Pediconi F, Fraioli F, Napoli A, Passariello R
Istituto di Radiologia, II Cattedra, Università degli Studi La Sapienza, Policlinico Umberto L, Roma.
Radiol Med. 2001 Jan-Feb;101(1-2):54-9.
Purpose of our study was to determine the feasibility and accuracy of contrast enhanced Turbo-MRA (CE-MRA) in the evaluation of patients with carotid artery stenosis, using a dynamic technique with multiple acquisitions.
37 patients with suspected carotid artery stenosis were studied with a 1.5 T magnet (Siemens Vision Plus) using, with a neck phased array coil, a dynamic tridimensional T1 weighted spoiled GRE (TR/TE/NEX: 3.8/1.4/1; Matrix = 110 x 160; FOV = 163 x 260 mm TA = 10 seconds for each sequence); 4 consecutive sequences were performed during the same breath hold, acquired after i.v. bolus injection with a power injector (Spectris, Medrad) of 15 ml of Gd-DTPA followed by 10 ml of saline solution (flow rate 2 ml/s). The beginning of the sequence coincided with the injection of Gd-DTPA. Images were reconstructed using a standard MIP algorithm, by selecting which of the sequences provided the highest enhancement. In all patients a DSA was also performed. Images were separately evaluated using conventional angiography as the gold standard and assessed for degree of stenosis by using NASCET criteria, and morphology of the plaque.
CE-MRA correctly evaluated the degree of stenosis in 71 of the 74 patients, while overestimated the remaining 3 cases correctly evaluated by DSA. In 12 cases ulcerations were adequately demonstrated by one of the radiologist, while 11 on 12 were depicted by the other one. CE MRA allowed to detect tandem lesions of the internal carotid arteries (by both radiologists) in 13 of 74 carotids studied. Stenosis at the origin of the common carotid arteries were correctly detected in 9 cases. Sensitivity, specificity and accuracy were respectively of 98, 97 and 99%.
In order to perform an optimal CE-MRA a dynamic technique must be performed to avoid venous filling. The possibility to use ultrafast imaging allows to selectively image the carotid arteries without jugular filling. The well known tendency to overestimate the degree of stenosis has not been found in this group of patients. CE-MRA is a rapid, reliable method to evaluate patients with suspected carotid artery stenosis. These results allow to consider dynamic CE-MRA as a valid method for direct imaging of the carotid arteries.
本研究的目的是使用多次采集的动态技术，确定对比增强 Turbo-MRA（CE-MRA）在评估颈动脉狭窄患者中的可行性和准确性。
对 37 例疑似颈动脉狭窄的患者使用 1.5T 磁共振成像仪（西门子 Vision Plus）进行研究，采用颈部相控阵线圈，运用动态三维 T1 加权扰相 GRE 序列（TR/TE/NEX：3.8/1.4/1；矩阵 = 110×160；视野 = 163×260mm；每个序列采集时间 = 10 秒）；在一次屏气期间连续进行 4 个序列的扫描，经静脉用高压注射器（Medrad Spectris）团注 15ml 钆喷酸葡胺，随后注入 10ml 生理盐水（流速 2ml/s）后进行采集。序列开始时间与钆喷酸葡胺注射时间同步。使用标准 MIP 算法重建图像，选择增强效果最佳的序列。所有患者均进行了数字减影血管造影（DSA）检查。图像分别以传统血管造影为金标准进行评估，并根据北美症状性颈动脉内膜切除术试验（NASCET）标准评估狭窄程度及斑块形态。
CE-MRA 在 74 例患者中的 71 例正确评估了狭窄程度，而高估了其余 3 例经 DSA 正确评估的病例。12 例溃疡病变中，一名放射科医生充分显示了其中 12 例中的 11 例，另一名放射科医生则显示了 12 例中的 11 例。CE-MRA 在 74 条研究的颈动脉中的 13 条中检测到颈内动脉串联病变（两名放射科医生均检测到）。正确检测到 9 例颈总动脉起始处狭窄。敏感性、特异性和准确性分别为 98%、97%和 99%。
为了进行最佳的 CE-MRA，必须采用动态技术以避免静脉显影。使用超快速成像的可能性使得能够在无颈静脉显影的情况下选择性地对颈动脉成像。在该组患者中未发现众所周知的高估狭窄程度的倾向。CE-MRA 是一种快速、可靠的评估疑似颈动脉狭窄患者的方法。这些结果使得可以将动态 CE-MRA 视为一种用于颈动脉直接成像的有效方法。
