Zghaib Tarek, Shahid Adeel, Pozzessere Chiara, Porter Kristin K, Chu Linda C, Eng John, Calkins Hugh, Kamel Ihab R, Nazarian Saman, Zimmerman Stefan L
Division of Cardiology, Johns Hopkins Medicine, 600 N Wolfe St, Carnegie 592, Baltimore, MD, 21287, USA.
§Russell A. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Medicine, Baltimore, MD, USA.
Int J Cardiovasc Imaging. 2018 Sep;34(9):1451-1458. doi: 10.1007/s10554-018-1355-8. Epub 2018 Apr 16.
Bolus timing is critical to optimal magnetic resonance angiography (MRA) acquisitions but can be challenging in some patients. Our purpose was to evaluate whether contrast-enhanced time-resolved magnetic resonance angiography (TR-MRA), a dynamic multiphase sequence that does not rely on bolus timing, is a viable alternative method to conventional 3D fast-long angle shot contrast-enhanced magnetic resonance angiography (CE-MRA). Coronal subtracted conventional CE-MRA images in 50 consecutive patients presenting for pre-atrial fibrillation ablation pulmonary venous (PV) mapping were compared with 50 TR-MRA images performed in 50 subsequent patients. The TR-MRA protocol was modified to optimize spatial resolution with slightly reduced temporal resolution (6.1 s scan time). Three experienced readers evaluated each scan's image quality and relative left atrial (LA) opacification based on a 4-point scale and diagnostic PV visualization in a binary fashion. Additionally, LA signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and PV dimensions were measured for both techniques. TR-MRA had significantly higher overall image quality (3.10 ± 0.69 vs. 2.42 ± 0.69, p < 0.0001), and LA opacification scores (3.33 ± 0.70 vs. 2.15 ± 1.13, p < 0.0001) compared to CE-MRA. The proportion of diagnostically visualized pulmonary veins was 137/150 (91%) in the CE-MRA group vs. 147/150 (98%) with TR-MRA (p = 0.010). Both SNR and CNR were higher with TR-MRA vs. CE-MRA (277.9 ± 48.9 vs. 106.8 ± 41, p = 0.002 and 100.3 ± 41.7 vs. 70.7 ± 48.0, p = 0.002, respectively). Inter-reader variance of individual PV measurements for each of the MR techniques ranged between 0.62 and 1.47 mm and the ICC for vein measurements was higher with TR-MRA (range: 0.62-0.81) compared to CE-MRA (range: 0.47-0.64). TR-MRA, modified to maximize spatial resolution, offers an alternative method for performing high quality MRA examinations in patients with AF. TR-MRA offers greater overall image quality, PV visualization, and similarly reproducible PV measurements compared to traditional CE-MRA, without the challenges of proper bolus timing.
团注时间对于获得最佳磁共振血管造影（MRA）图像至关重要，但在某些患者中可能具有挑战性。我们的目的是评估对比增强时间分辨磁共振血管造影（TR-MRA），一种不依赖团注时间的动态多期序列，是否是传统三维快速长角激发对比增强磁共振血管造影（CE-MRA）的可行替代方法。对50例连续接受心房颤动消融术前肺静脉（PV）造影的患者的冠状面减影传统CE-MRA图像与随后50例患者的50幅TR-MRA图像进行比较。对TR-MRA方案进行了修改，以在略微降低时间分辨率（扫描时间6.1秒）的情况下优化空间分辨率。三位经验丰富的阅片者根据4分制评估每次扫描的图像质量和左心房（LA）相对显影程度，并以二元方式评估PV的诊断性可视化情况。此外，还测量了两种技术的LA信噪比（SNR）、对比噪声比（CNR）和PV尺寸。与CE-MRA相比，TR-MRA的整体图像质量显著更高（3.10±0.69对2.42±0.69，p<0.0001），LA显影评分也更高（3.33±0.70对2.15±1.13，p<0.0001）。CE-MRA组诊断性可视化肺静脉的比例为137/150（91%），而TR-MRA组为147/（98%）（p=0.010）。与CE-MRA相比，TR-MRA的SNR和CNR均更高（分别为277.9±48.9对106.8±41，p=0.002；100.3±41.7对70.7±48.0，p=0.002）。每种MR技术的个体PV测量的阅片者间差异在0.62至1.47毫米之间，与CE-MRA（范围：0.47-0.64）相比，TR-MRA的静脉测量的组内相关系数（ICC）更高（范围：0.62-0.81）。经过修改以最大化空间分辨率的TR-MRA为房颤患者进行高质量MRA检查提供了一种替代方法。与传统CE-MRA相比，TR-MRA具有更高的整体图像质量、PV可视化效果以及相似的可重复PV测量结果，且不存在合适团注时间的挑战。
