Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH, 45229, USA.
Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
J Cardiovasc Magn Reson. 2020 Jul 27;22(1):54. doi: 10.1186/s12968-020-00642-y.
Although the breath-hold cine balanced steady state free precession (bSSFP) imaging is well established for assessment of biventricular volumes and function, shorter breath-hold times or no breath-holds are beneficial in children and severely ill or sedated patients.
Clinical cardiovascular magnetic resonance (CMR) examinations from September 2019 to October 2019 that included breath-hold (BH) and free-breathing (FB) cine bSSFP imaging accelerated using compressed sensitivity encoding (C-SENSE) factor of 3 in addition to the clinical standard BH cine bSSFP imaging using SENSE factor of 2 were analyzed retrospectively. Patients with structurally normal hearts who could perform consistent BHs were included. Aortic flow measured by phase contrast acquisition was used as a reference for the left ventricular (LV) stroke volume. Comparative analysis was performed for evaluation of biventricular volumes and function, imaging times, quantitative image quality, and qualitative image scoring.
There were 26 patients who underwent all three cine scans during the study period (16.7 ± 6.4 years, body surface area (BSA) 1.6 ± 0.4 m, heart rate 83 ± 7 beats/min). BH durations of 8 ± 1 s with C-SENSE = 3 were significantly shorter (p < 0.001) by 33% compared to 12 ± 1 s with SENSE = 2. Actual scan time for BH SENSE (4.9 ± 1.2 min) was comparable to that with FB C-SENSE (5.2 ± 1.5 min; p= NS). Biventricular stroke volume and ejection fraction, and LV mass computed using all three sequences were comparable. There was a small but statistically significant (p < 0.05) difference in LV end-diastolic volume (- 3.0 ± 6.8 ml) between BH SENSE and FB C-SENSE. There was a small but statistically significant (p < 0.005) difference in end-diastolic LV (- 5.0 ± 7.7 ml) and RV (- 6.0 ± 8.5 ml) volume and end-systolic LV (- 3.2 ± 4.3 ml) and RV(- 4.2 ± 6.8 ml) volumes between BH C-SENSE and FB C-SENSE. The LV stroke volumes from all three sequences had excellent correlations (r = 0.96, slope = 0.98-1.02) with aortic flow, with overestimation by 2.7 (5%) to 4.6 (8%) ml/beat. The image quality score was Excellent (16 of 26) to Good (10 of 26) with BH SENSE, Excellent (13 of 26) to Good (13 of 26) with BH C-SENSE, and Excellent (3 of 26) to Good (21 of 26) to Adequate (2 of 26) with FB C-SENSE.
Image quality and ventricular volumetric and functional indices using either BH or FB C-SENSE cine bSSFP imaging were comparable to standard BH SENSE cine bSSFP imaging while maintaining nominally identical spatio-temporal resolution. This accelerated image acquisition provides an alternative to accommodate patients with impaired BH capacity.
尽管屏气电影平衡稳态自由进动（bSSFP）成像在评估双心室容积和功能方面已经得到很好的建立，但在儿童和重病或镇静患者中，较短的屏气时间或无需屏气是有益的。
回顾性分析 2019 年 9 月至 2019 年 10 月期间进行的临床心血管磁共振（CMR）检查，这些检查包括使用压缩灵敏度编码（C-SENSE）因子 3 加速的屏气（BH）和自由呼吸（FB）电影 bSSFP 成像，以及使用灵敏度因子 2 的临床标准 BH 电影 bSSFP 成像。纳入能够进行一致 BH 的结构正常心脏的患者。相位对比采集测量的主动脉流量用作左心室（LV）搏出量的参考。进行了对比分析，以评估双心室容积和功能、成像时间、定量图像质量和定性图像评分。
在研究期间，共有 26 名患者接受了所有三种电影扫描（16.7±6.4 岁，体表面积（BSA）1.6±0.4m，心率 83±7 次/分）。使用 C-SENSE=3 的 BH 持续时间为 8±1s，比使用 SENSE=2 的 BH 持续时间 12±1s 短 33%（p<0.001）。BH SENSE 的实际扫描时间（4.9±1.2 分钟）与 FB C-SENSE（5.2±1.5 分钟）相当（p=NS）。使用所有三种序列计算的双心室搏出量和射血分数以及 LV 质量是可比的。LV 舒张末期容积（BH SENSE 与 FB C-SENSE 之间为-3.0±6.8ml）之间存在小但具有统计学意义的差异（p<0.05）。LV 舒张末期（-5.0±7.7ml）和 RV 舒张末期（-6.0±8.5ml）容积和 LV 收缩末期（-3.2±4.3ml）和 RV 收缩末期（-4.2±6.8ml）容积之间存在小但具有统计学意义的差异（p<0.005）。所有三种序列的 LV 搏出量与主动脉流量具有极好的相关性（r=0.96，斜率=0.98-1.02），估计值高出 2.7（5%）至 4.6（8%）ml/beat。BH SENSE 的图像质量评分为优秀（26 例中有 16 例）至良好（26 例中有 10 例），BH C-SENSE 的图像质量评分为优秀（26 例中有 13 例）至良好（26 例中有 13 例），FB C-SENSE 的图像质量评分为优秀（26 例中有 3 例）至良好（26 例中有 21 例）至尚可（26 例中有 2 例）。
使用 BH 或 FB C-SENSE 电影 bSSFP 成像获得的图像质量以及心室容积和功能指数与标准 BH SENSE 电影 bSSFP 成像相当，同时保持名义上相同的时空分辨率。这种加速的图像采集为适应屏气能力受损的患者提供了一种替代方法。
