Purpose

Right ventricular (RV) function is increasingly recognized for its prognostic value in many disease states. As with the left ventricle (LV), strain-based measurements may have better prognostic value than typical chamber volumes or ejection fraction. Complete functional characterization of the RV requires high-resolution, 3D displacement tracking methods, which have been prohibitively challenging to implement. Zonal excitation during Displacement ENcoding with Stimulated Echoes (DENSE) magnetic resonance imaging (MRI) has helped reduce scan time for 2D LV strain quantification. We hypothesized that zonal excitation could alternatively be used to reproducibly acquire higher resolution, 3D-encoded DENSE images for quantification of bi-ventricular strain within a single breath-hold.

Methods

We modified sequence parameters for a 3D zonal excitation DENSE sequence to achieve in-plane resolution < 2 mm and acquired two sets of images in eight healthy adult male volunteers with median (IQR) age 32.5 (32.0–33.8) years. We assessed the inter-test reproducibility of this technique, and compared computed strains and torsion with previously published data.

Results

Data for one subject was excluded based on image artifacts. Reproducibility for LV (CoV: 6.1–9.0%) and RV normal strains (CoV: 6.3–8.2%) and LV torsion (CoV = 7.1%) were all very good. Reproducibility of RV torsion was lower (CoV = 16.7%), but still within acceptable limits. Computed global strains and torsion were within reasonable agreement with published data, but further studies in larger cohorts are needed to confirm.

Conclusion

Reproducible acquisition of 3D-encoded biventricular myocardial strain data in a breath-hold is feasible using DENSE with zonal excitation.

中文翻译：

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带带状激励的 3D 编码 DENSE MRI，用于在屏气期间量化双心室心肌应变

目的

右心室 (RV) 功能因其在许多疾病状态中的预后价值而日益受到认可。与左心室 (LV) 一样，基于应变的测量可能比典型的心室容积或射血分数具有更好的预后价值。RV 的完整功能表征需要高分辨率的 3D 位移跟踪方法，这些方法的实施极具挑战性。使用受激回波 (DENSE) 磁共振成像 (MRI) 进行位移编码期间的区域激励有助于减少 2D LV 应变量化的扫描时间。我们假设区域激励可以替代地用于可重复地获取更高分辨率、3D 编码的 DENSE 图像，用于在一次屏气期间量化双心室应变。

方法

我们修改了 3D 区域激发 DENSE 序列的序列参数，以实现面内分辨率 < 2 mm，并在八名中位 (IQR) 年龄为 32.5 (32.0–33.8) 岁的健康成年男性志愿者中采集了两组图像。我们评估了该技术的测试间再现性，并将计算出的应变和扭转与先前发布的数据进行了比较。

结果

根据图像伪影排除了一名受试者的数据。LV（CoV：6.1-9.0%）和 RV 正常株（CoV：6.3-8.2%）和 LV 扭转（CoV = 7.1%）的再现性都非常好。RV 扭转的再现性较低 (CoV = 16.7%)，但仍在可接受的范围内。计算出的全局应变和扭转与已发表的数据在合理的范围内，但需要在更大的队列中进行进一步的研究来证实。

结论

使用带区域激励的 DENSE，在屏气时可重复采集 3D 编码的双心室心肌应变数据。