Tkach J A, Ding X, Ruggieri P M, Obuchowski N A, Lieber M, Masaryk T J
Department of Diagnostic Radiology, Cleveland Clinic Foundation, OH 44195, USA.
AJNR Am J Neuroradiol. 1997 Aug;18(7):1339-47.
To implement and assess the application of segmented three-dimensional echo-planar MR imaging time-of-flight flow sequences for studying the anatomy of the cervical carotid arteries at 1.5 T.
The 3-D echo-planar sequences were segmented along the in-plane phase-encoding direction. Echo train lengths (ETLs) of 3 and 5 and signal bandwidths of +/-25, +/-33, and +/-50 KHz were tested along with a conventional (ETL = 1) 3-D MR flow study in six healthy volunteers and in five patients with known arteriosclerotic disease involving the carotid bifurcation as confirmed by conventional angiography. The volunteer data were used to rank the techniques with respect to vessel dimension, vessel/background contrast, and quality by four trained neuroradiologists. For the patient studies, the percentage of stenoses was measured for all MR studies and compared against the conventional angiographic data using the criteria of the North American Symptomatic Carotid Endarterectomy Trial.
Using Wilcoxon's test statistic and a significance level of .05, we found that the conventional MR flow examination was better than the segmented techniques and that the segmented techniques with ETL of 3 were superior to their counterparts with ETL of 5. For the ETL of 3 techniques, the high-bandwidth studies were inferior to their lower bandwidth counterparts; however, there was no significant difference between the performance of the medium- and low-bandwidth sequences. The patient data revealed that the segmented techniques consistently overestimated the severity of stenosis; however, in no instance did any of the segmented examinations erroneously indicate the presence of disease.
The reduction in acquisition time and the zero false-positive rate we obtained suggest that segmented 3-D echo-planar MR flow techniques may be used as a screening/locating study for cervical carotid artery disease.
在1.5T磁场下，应用并评估分段三维回波平面磁共振成像时间飞跃血流序列研究颈总动脉的解剖结构。
三维回波平面序列沿面内相位编码方向进行分段。在6名健康志愿者和5名经传统血管造影证实患有累及颈动脉分叉的动脉硬化疾病患者中，测试了回波链长度（ETL）为3和5以及信号带宽为+/-25、+/-33和+/-50kHz的序列，并与传统的（ETL = 1）三维磁共振血流研究进行了比较。由4名训练有素的神经放射科医生根据血管尺寸、血管/背景对比度和质量对志愿者数据进行技术排序。对于患者研究，测量所有磁共振研究的狭窄百分比，并根据北美症状性颈动脉内膜切除术试验的标准与传统血管造影数据进行比较。
使用Wilcoxon检验统计量和显著性水平0.05，我们发现传统的磁共振血流检查优于分段技术，ETL为3的分段技术优于ETL为5的技术。对于ETL为3的技术，高带宽研究不如低带宽研究；然而，中带宽和低带宽序列的性能之间没有显著差异。患者数据显示，分段技术始终高估狭窄程度；然而，在任何情况下，任何分段检查都没有错误地表明疾病的存在。
我们获得的采集时间缩短和零假阳性率表明，分段三维回波平面磁共振血流技术可作为颈总动脉疾病的筛查/定位研究。
