Altabella Luisa, Borrazzo Cristian, Carnì Marco, Galea Nicola, Francone Marco, Fiorelli Andrea, Di Castro Elisabetta, Catalano Carlo, Carbone Iacopo
Medical Physics Unit, Policlinico Umberto I, Rome, Italy.
Medical Physics Unit, Policlinico Umberto I, Rome, Italy; Department of Molecular Medicine, University of Rome La Sapienza, Viale Regina Elena 291, 00161 Rome, Italy.
Phys Med. 2017 Jan;33:47-55. doi: 10.1016/j.ejmp.2016.12.002. Epub 2016 Dec 18.
Cardiac magnetic resonance (CMR) is a useful non-invasive tool for characterizing tissues and detecting myocardial fibrosis and edema. Estimation of extracellular volume fraction (ECV) using T1 sequences is emerging as an accurate biomarker in cardiac diseases associated with diffuse fibrosis. In this study, automatic software for T1 and ECV map generation consisting of an executable file was developed and validated using phantom and human data.
T1 mapping was performed in phantoms and 30 subjects (22 patients and 8 healthy subjects) on a 1.5T MR scanner using the modified Look-Locker inversion-recovery (MOLLI) sequence prototype before and 15 min after contrast agent administration. T1 maps were generated using a Fast Nonlinear Least Squares algorithm. Myocardial ECV maps were generated using both pre- and post-contrast T1 image registration and automatic extraction of blood relaxation rates.
Using our software, pre- and post-contrast T1 maps were obtained in phantoms and healthy subjects resulting in a robust and reliable quantification as compared to reference software. Coregistration of pre- and post-contrast images improved the quality of ECV maps. Mean ECV value in healthy subjects was 24.5%±2.5%.
This study demonstrated that it is possible to obtain accurate T1 maps and informative ECV maps using our software. Pixel-wise ECV maps obtained with this automatic software made it possible to visualize and evaluate the extent and severity of ECV alterations.
心脏磁共振成像（CMR）是一种用于组织特征化以及检测心肌纤维化和水肿的有用的非侵入性工具。利用T1序列估算细胞外容积分数（ECV）正在成为与弥漫性纤维化相关的心脏疾病中一种准确的生物标志物。在本研究中，开发了一种由可执行文件组成的用于生成T1和ECV图的自动软件，并使用体模和人体数据进行了验证。
在1.5T MR扫描仪上，使用改良的Look-Locker反转恢复（MOLLI）序列原型，在30名受试者（22例患者和8名健康受试者）及体模中，于注射造影剂前和注射后15分钟进行T1 mapping。使用快速非线性最小二乘法生成T1图。利用造影剂注射前后的T1图像配准和血液弛豫率的自动提取生成心肌ECV图。
使用我们的软件，在体模和健康受试者中获得了造影剂注射前后的T1图，与参考软件相比，实现了稳健且可靠的定量分析。造影剂注射前后图像的配准提高了ECV图的质量。健康受试者的平均ECV值为24.5%±2.5%。
本研究表明，使用我们的软件可以获得准确的T1图和信息量丰富的ECV图。通过这种自动软件获得的逐像素ECV图使得可视化和评估ECV改变的范围和严重程度成为可能。
