EZ-Step技术在胸主动脉3.0T磁共振血管造影中的应用

目的 评估EZ-Step技术在胸主动脉对比增强磁共振血管造影(CE MRA)中的应用价值.方法 60例临床怀疑胸主动脉疾病的患者,随机接受胸主动脉常规CE MRA或应用EZ-Step技术的CE MRA检查,后者扫描过程中应用<0.1 ms非选择性激励射频脉冲代替常规选择性激励射频脉冲;除视野外,其余各项MR扫描参数及对比剂用量均尽量保持一致.比较胸主动脉常规CE MRA及应用EZ-Step的CE MRA二种技术总的扫描时间、图像质量评分以及图像信噪比等.结果 应用EZ-Step技术后,MRA检查时间显著缩短,与常规CE MRA图像质量无明显差异(分别为2.48±0.50和2.66±0.56,P>0.05);图像信噪比轻度下降(P<0.05),但诊断准确性未受影响.结论 在进行胸主动脉MRA时,使用EZ-Step技术可以缩短扫描时间,获得良好的图像质量,是利用3.0T MR诊断急性主动脉疾病有效而省时的方法.

Scoutless EZ-Step in contrast-enhanced magnetic resonance angiography of thoracic aorta at 3.0T MR

Objective To evaluate the scoutless technique, termed as EZ-Step, in contrast-enhanced magnetic resonance angiography (CE-MRA) compared with conventional three dimensional CE-MRA of thoracic aorta at 3.0T MR system. Methods Sixty consecutive patients were divided into two groups randomly and underwent the thoracic aorta MRA with scoutless EZ-Step and conventional CE-MRA, respectively, on GE Signa Exite HD 3.0T scanner. For EZ-Step group, the standard selective RF excitation (typically about 1-2 ms in duration) was replaced by short, spatial nonselective RF pulse with a duration less than 0.1 ms. Whole volume excitation was achieved by applying the RF pulse without a slice-selection gradient. Except for field of view, other parameters and contrast agents were similar in two groups. The total scan time of MRA was recorded. The image quality was estimated by two radiologists independently according to the score grading system. The SNR was calculated and compared between the two groups. Results The average scan time for EZ-Step was less than that of conventional CE-MRA. No statistical difference of image quality score was found between the two groups (2.48±0.50 vs 2.66±0.56, P>0.05), while SNR slightly decreased in EZ-Step group than conventional group (P<0.05). No misdiagnosis occurred in both groups. Conclusion In thoracic aorta MRA, the scoutless EZ-Step technique may reduce scan time obviously and provide comparable image quality at 3.0T MR system, and it can be used as an effective and time-saving method at 3.0T for acute aortic diseases.