Free-breathing myocardial T2* mapping using GRE-EPI and automatic Non-rigid motion correction

Journal of Cardiovascular Magnetic Resonance

Research

Nathan Lamba¹  Juliana Serafim da Silveira¹  Subha V. Raman²  Orlando P. Simonetti³  Sharath Subramanian⁴  Marie-Pierre Jolly⁵  George Mathew⁶  David N. Firmin⁷  Dudley J. Pennell⁷  Ning Jin⁸ 

[1] Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA;Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA;Department of Internal Medicine – Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA;Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA;Department of Internal Medicine – Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA;Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA;Department of Radiology, The Ohio State University, Columbus, OH, USA;Department of Internal Medicine – Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA;Imaging & Computer Vision, Siemens Corporation, Corporate Technology, Princeton, NJ, USA;NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Trust, London, UK;NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Trust, London, UK;National Heart and Lung Institute, Imperial College, London, UK;Siemens Medical Solutions USA, Inc, 460 West 12th Ave, Room 311, OH 43210, Columbus, OH, USA;

关键词: Cardiac;    T2*;    Mapping;    Free-breathing;    Iron overload;    GRE-EPI;    Motion correction;   

DOI  :  10.1186/s12968-015-0216-z

 received in 2015-08-05, accepted in 2015-12-09,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundMeasurement of myocardial T2* is becoming widely used in the assessment of patients at risk for cardiac iron overload. The conventional breath-hold, ECG-triggered, segmented, multi-echo gradient echo (MGRE) sequence used for myocardial T2* quantification is very sensitive to respiratory motion and may not be feasible in patients who are unable to breath-hold. We propose a free-breathing myocardial T2* mapping approach that combines a single-shot gradient-echo echo-planar imaging (GRE-EPI) sequence for T2*-weighted image acquisition with automatic non-rigid motion correction (MOCO) of respiratory motion between single-shot images.MethodsECG-triggered T2*-weighted images at different echo times were acquired by a black-blood, single-shot GRE-EPI sequence during free-breathing. A single image at a single TE is acquired in each heartbeat. Automatic non-rigid MOCO was applied to correct for in-plane respiratory motion before pixel-wise T2* mapping. In a total of 117 patients referred for clinical cardiac magnetic resonance exams, the free-breathing MOCO GRE-EPI sequence was compared to the breath-hold segmented MGRE approach. Image quality was scored independently by 2 experienced observers blinded to the particular image acquisition strategy. T2* measurements in the interventricular septum and in the liver were compared for the two methods in all cases with adequate image quality.ResultsT2* maps were acquired in all 117 patients using the breath-hold MGRE and the free-breathing MOCO GRE-EPI approaches, including 8 patients with myocardial iron overload and 25 patients with hepatic iron overload. The mean image quality of the free-breathing MOCO GRE-EPI images was scored significantly higher than that of the breath-hold MGRE images by both reviewers. Out of the 117 studies, 21 breath-hold MGRE studies (17.9 % of all the patients) were scored to be less than adequate or very poor by both reviewers, while only 2 free-breathing MOCO GRE-EPI studies were scored to be less than adequate image quality. In a comparative evaluation of the images with at least adequate quality, the intra-class correlation coefficients for myocardial and liver T2* were 0.868 and 0.986 respectively (p < 0.001), indicating that the T2* measured by breath-hold MGRE and free-breathing MOCO GRE-EPI were in close agreement. The coefficient of variation between the breath-hold and free-breathing approaches for myocardial and liver T2* were 9.88 % and 9.38 % respectively. Bland-Altman plots demonstrated good absolute agreement of T2* in the interventricular septum and the liver from the free-breathing and breath-hold approaches (mean differences -0.03 and 0.16 ms, respectively).ConclusionThe free-breathing approach described for T2* mapping using MOCO GRE-EPI enables accurate myocardial and liver T2* measurements and is insensitive to respiratory motion.

【 授权许可】

CC BY   
© Jin et al. 2015