Berganza Fernando M, de Alba Cesar Gonzalez, Özcelik Nazire, Adebo Dilachew
Division of Pediatric Cardiology, Driscoll Children's Hospital, Corpus Christi, TX, USA.
Division of Pediatric Cardiology, Memorial Hermann Children's Hospital, University of Texas Medical School at Houston, Houston, TX, USA.
Pediatr Cardiol. 2017 Mar;38(3):566-574. doi: 10.1007/s00246-016-1549-6. Epub 2017 Jan 5.
Cardiac magnetic resonance imaging is an important tool to evaluate cardiac anatomy and ventricular size and function after repaired tetralogy of Fallot. Magnetic resonance tissue tagging is the gold standard for evaluation of myocardial strain. However, myocardial tagging strain requires tagged images to be obtained prospectively, during the scan and with limited temporal resolution. Cardiac magnetic resonance feature tracking is a new tool that allows the retrospective analysis of cine images. There is limited experience with cardiac magnetic resonance feature tracking strain analysis in children. The medical records of patients with repaired tetralogy of Fallot that had a cardiac magnetic resonance (CMR) study from December 2013 to June 2015 were reviewed. The control group included patients who underwent a CMR with normal cardiac anatomy and ventricular function. Global longitudinal, circumferential and radial strain parameters (2D and 3D) were obtained by retrospectively contouring cine images from ventricular short axis, two chamber and four chamber views using post-processing software (Circle CVi, Calgary, Canada). The correlation between conventional ventricular function parameters and ventricular strain was performed using Pearson's correlation. The mean age of tetralogy of Fallot and control subjects was 12.4 and 14.1 years, respectively. In patients after repaired tetralogy of Fallot, the mean left ventricular global 2D and 3D circumferential strains were -17.4 ± 2.9 and -10.1 ± 3, respectively. The mean indexed right ventricular end-diastolic volume was 135.4 cc m ± 46 compared to 75.7 cc m ± 17 in control subjects (P = 0.0001, CI 95%). Left ventricular global circumferential 3D strain showed a statistically significant difference in patients after TOF repair compared to normal subjects (-10.1 ± 3 vs. -14.71 ± 1.9, P = 0.00001). A strong correlation between left ventricular global circumferential 3D strain and right ventricular end-diastolic volume (P ≤ 0.0001) was noted. We found a strong correlation between left ventricular circumferential 3D strain and indexed right ventricular end-diastolic volume, as well as a strong correlation between left ventricular longitudinal 2D strain and right ventricular ejection fraction. Circumferential 3D strain may be a suitable tool to detect early abnormalities of ventricular myocardium even before the ejection fraction becomes compromised. Large-scale prospective studies are recommended.
心脏磁共振成像（CMR）是评估法洛四联症修复术后心脏解剖结构、心室大小及功能的重要工具。磁共振组织标记是评估心肌应变的金标准。然而，心肌标记应变需要在扫描过程中前瞻性地获取标记图像，且时间分辨率有限。心脏磁共振特征追踪是一种可对电影图像进行回顾性分析的新工具。目前关于儿童心脏磁共振特征追踪应变分析的经验有限。我们回顾了2013年12月至2015年6月期间接受心脏磁共振（CMR）检查的法洛四联症修复术后患者的病历。对照组包括心脏解剖结构和心室功能正常的接受CMR检查的患者。使用后处理软件（加拿大卡尔加里的Circle CVi），通过对心室短轴、两腔心和四腔心视图的电影图像进行回顾性轮廓分析，获得整体纵向、圆周和径向应变参数（二维和三维）。使用Pearson相关性分析传统心室功能参数与心室应变之间的相关性。法洛四联症患者和对照组的平均年龄分别为12.4岁和14.1岁。在法洛四联症修复术后患者中，左心室整体二维和三维圆周应变的平均值分别为-17.4±2.9和-10.1±3。与对照组（75.7 cc/m±17）相比，平均右心室舒张末期指数容积为135.4 cc/m±46（P = 0.0001，95%置信区间）。与正常受试者相比，法洛四联症修复术后患者的左心室整体圆周三维应变存在统计学显著差异（-10.1±3 vs. -14.71±1.9，P = 0.00001）。注意到左心室整体圆周三维应变与右心室舒张末期容积之间存在强相关性（P≤0.0001）。我们发现左心室圆周三维应变与右心室舒张末期指数容积之间存在强相关性，以及左心室纵向二维应变与右心室射血分数之间存在强相关性。圆周三维应变可能是一种合适的工具，即使在射血分数受损之前也能检测到心室心肌的早期异常。建议进行大规模前瞻性研究。
