Department of Radiology, University Hospital of California, San Francisco, California 94143-0628, USA.
J Magn Reson Imaging. 2011 Jun;33(6):1440-6. doi: 10.1002/jmri.22566.
To compare aortic flow profiles at the level of the proximal descending (PDAo) and distal descending aorta (DDAo) in patients investigated for coarctation of the aorta (CoA), and compare their respective diagnostic value for predicting severe CoA. Diastolic flow decay in the PDAo predicts severe CoA, but flow measurements at this level are limited by flow turbulence, aliasing, and stent-related artifacts.
We studied 49 patients evaluated for CoA with phase contrast magnetic resonance imaging (PC-MRI). Parameters of diastolic flow decay in the PDAo and DDAo were compared. Their respective diagnostic value was compared with the standard reference of transcatheter peak gradient ≥20 mmHg.
Flow measurement in the PDAo required repeated acquisition with adjustment of encoding velocity or location of the imaging plane in 69% of patients; measurement in the DDAo was achieved in single acquisition in all cases. Parameters of diastolic flow decay in the PDAo and DDAo, including rate-corrected (RC) deceleration time and RC flow deceleration yielded a good correlation (r = 0.78; P < 0.01, and r = 0.92; P < 0.01), and a similar diagnostic value for predicting severe CoA. The highest diagnostic accuracy was achieved by RC deceleration time at DDAo (sensitivity 85%, specificity 85%).
Characterization of aortic flow profiles at the DDAo offers a quick and reliable noninvasive means of assessing hemodynamically significant CoA.
比较主动脉缩窄（CoA）患者降主动脉近端（PDAo）和降主动脉远端（DDAo）的血流廓形，并比较各自预测严重 CoA 的诊断价值。PDAo 的舒张期血流衰减预测严重 CoA，但该水平的血流测量受到血流湍流、混叠和支架相关伪影的限制。
我们研究了 49 例经相位对比磁共振成像（PC-MRI）评估的 CoA 患者。比较了 PDAo 和 DDAo 舒张期血流衰减的参数。将其各自的诊断价值与经导管峰值梯度≥20mmHg 的标准参考值进行比较。
69%的患者需要重复采集并调整编码速度或成像平面位置才能进行 PDAo 的血流测量；所有患者均能在单次采集时获得 DDAo 的血流测量值。PDAo 和 DDAo 舒张期血流衰减的参数，包括校正后的（RC）减速时间和 RC 流量减速，相关性良好（r=0.78；P<0.01，r=0.92；P<0.01），且对预测严重 CoA 的诊断价值相似。DDAo 的 RC 减速时间具有最高的诊断准确性（敏感性 85%，特异性 85%）。
DDAo 处的主动脉血流廓形特征为评估血流动力学显著 CoA 提供了一种快速可靠的非侵入性方法。
