Noninvasive pressure difference mapping derived from 4D flow MRI in patients with unrepaired and repaired aortic coarctation
Noninvasive pressure difference mapping derived from 4D flow MRI in patients with unrepaired and repaired aortic coarctation
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DOI：
10.3978/j.issn.2223-3652.2014.03.03
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发表时间：
2014-04-01
影响因子：
2.4
通讯作者：
Ley, Sebastian
中科院分区：
文献类型：
--
作者：
Rengier, Fabian;Delles, Michael;Ley, Sebastian
目的：开发一种计算和可视化时间分辨速度编码三维相对比磁共振成像（4D血流MRI）产生的压力差的方法，并将未修复和修复的主动脉缩窄患者与年轻健康志愿者的压力差图进行比较。方法：对4例主动脉缩窄患者（平均年龄17岁，年龄3-28岁，女1名，男3名）和4名无心血管疾病史的年轻健康志愿者（平均年龄24岁，年龄20-27岁，女1名，男3名）采用1.5 t临床MR扫描，获取修复前后的4D血流MRI数据。使用内部开发的图像处理软件进行图像分析。根据Navier-Stokes方程计算相对压力。结果：开发了一种直观可视化压差图的标准化方法，并成功应用于所有纳入的患者和志愿者。年轻健康志愿者在收缩期中期胸主动脉相对压力分布平稳、规律，所有被分析志愿者的相对压力分布非常相似。与志愿者相比，患者表现出不安的压力。这些变化包括所有患者的主动脉峡部压力下降，修复后残留狭窄患者的主动脉弓相对压力增加，补片主动脉成形术后患者的降主动脉相对压力增加。结论：4D血流MRI获得的压差图可以描述修复和未修复主动脉缩窄患者空间压力分布的变化。这项技术可能有助于识别主动脉缩窄修复后潜在并发症的病理生理状况。
Purpose: To develop a method for computing and visualizing pressure differences derived from time-resolved velocity-encoded three-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) and to compare pressure difference maps of patients with unrepaired and repaired aortic coarctation to young healthy volunteers.Methods: 4D flow MRI data of four patients with aortic coarctation either before or after repair (mean age 17 years, age range 3-28, one female, three males) and four young healthy volunteers without history of cardiovascular disease (mean age 24 years, age range 20-27, one female, three males) was acquired using a 1.5-T clinical MR scanner. Image analysis was performed with in-house developed image processing software. Relative pressures were computed based on the Navier-Stokes equation.Results: A standardized method for intuitive visualization of pressure difference maps was developed and successfully applied to all included patients and volunteers. Young healthy volunteers exhibited smooth and regular distribution of relative pressures in the thoracic aorta at mid systole with very similar distribution in all analyzed volunteers. Patients demonstrated disturbed pressures compared to volunteers. Changes included a pressure drop at the aortic isthmus in all patients, increased relative pressures in the aortic arch in patients with residual narrowing after repair, and increased relative pressures in the descending aorta in a patient after patch aortoplasty.Conclusions: Pressure difference maps derived from 4D flow MRI can depict alterations of spatial pressure distribution in patients with repaired and unrepaired aortic coarctation. The technique might allow identifying pathophysiological conditions underlying complications after aortic coarctation repair.