Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Radiology and Imaging Sciences, Emory University, Atlanta, Georgia.
J Magn Reson Imaging. 2019 Mar;49(3):731-743. doi: 10.1002/jmri.26304. Epub 2018 Oct 8.
Knowledge of tissue properties of the abdominal aorta can improve understanding of vascular disease and guide interventional approaches. Existing MRI methods to quantify aortic wall displacement and strain are unable to discern circumferential heterogeneity.
To assess regional variation in abdominal aortic wall displacement and strain as a function of circumferential position using spiral cine displacement encoding with stimulated echoes (DENSE).
Prospective.
Cardiovascular disease-free men (n = 8) and women (n = 9) ages 30-42.
Prospective electrocardiogram (ECG)-gated and navigator echo-gated spiral, cine 2D DENSE and retrospective ECG-gated phase contrast MR (PCMR) sequences at 3T.
In-plane displacement values of the aortic wall acquired with DENSE were used to determine radial and circumferential aortic wall motion. A quadrilateral-based 2D strain calculation method was implemented to determine strain from the displacement field. Peak displacement and its radial and circumferential contributions as well as peak circumferential strain were compared among eight circumferential wall segments. Distensibility was calculated using PCMR and compared with homogenized circumferential strain.
To account for repeated measurements in volunteers, linear mixed models for mean sector values were created for displacement magnitude, circumferential displacement, radial displacement, and circumferential strain. Comparisons were made between sectors. Calculated distensibility and homogenized circumferential strain were compared using Bland-Altman analysis. Statistical significance was defined as P < 0.05.
Displacement was highest in the anterior wall (1.5 ± 0.7 mm) and was primarily in the radial as compared with circumferential direction (1.04 ± 0.05 mm vs. 0.81 ± 0.42 mm). Circumferential strain was highest in the lateral walls (left 0.16 ± 0.05 and right 0.21 ± 0.12) with homogenized circumferential strain of 0.14 ± 0.05.
DENSE imaging in the abdominal aortic wall demonstrated that the anterior aortic wall exhibits the greatest displacement, while the lateral wall experiences the largest circumferential strain.
3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:731-743.
了解腹主动脉组织特性可以帮助我们更好地理解血管疾病并指导介入治疗。现有的 MRI 方法可以定量评估主动脉壁的位移和应变，但无法分辨圆周方向的异质性。
使用螺旋电影弥散编码（DENSE）评估腹主动脉壁位移和应变的圆周位置依赖性。
前瞻性研究。
心血管疾病阴性的 30-42 岁男性（n=8）和女性（n=9）。
前瞻性心电图（ECG）门控和导航回波门控螺旋、电影二维 DENSE 和回顾性 ECG 门控相位对比磁共振（PCMR）序列（3T）。
DENSE 获得的主动脉壁内平面位移值用于确定主动脉壁的径向和圆周运动。采用基于四边形的二维应变计算方法，从位移场确定应变。比较 8 个圆周壁段的峰值位移及其径向和圆周分量，以及峰值圆周应变。使用 PCMR 计算可扩张性，并与均匀圆周应变进行比较。
为了对志愿者进行重复测量，为位移幅度、圆周位移、径向位移和圆周应变的平均值创建了线性混合模型。比较各部位之间的差异。使用 Bland-Altman 分析比较计算出的可扩张性和均匀圆周应变。统计显著性定义为 P<0.05。
前壁的位移最大（1.5±0.7mm），主要是径向方向（1.04±0.05mm），而不是圆周方向（0.81±0.42mm）。侧壁的圆周应变最大（左侧 0.16±0.05，右侧 0.21±0.12），均匀圆周应变 0.14±0.05。
腹主动脉壁 DENSE 成像显示，前主动脉壁的位移最大，而侧壁的圆周应变最大。
3 级 技术功效：2 级 J. 磁共振成像 2019；49：731-743.
