Free-breathing T2* mapping using respiratory motion corrected averaging

Journal of Cardiovascular Magnetic Resonance

Research

Laura-Ann McGill¹  Dudley J Pennell¹  Peter Gatehouse¹  Peter Kellman²  Christine Mancini²  Hui Xue²  Michael S Hansen²  Andrew E Arai²  W Patricia Bandettini²  Christopher M Sandino²  Bruce S Spottiswoode³  Amna Abdel-Gadir⁴  James C Moon⁴  Stefania Rosmini⁴  Thomas A Treibel⁴ 

[1] Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, SW3 6NP, London, UK;National Heart, Lung, and Blood Institute, National Institutes of Health, DHHS, 10 Center Drive MSC-1061, 20892, Bethesda, MD, USA;Siemens Medical Solutions, USA, Inc, Chicago, IL, USA;The Heart Hospital, 16-18 Westmoreland Street, W1G 8PH, London, UK;

关键词: T2*;    R2*;    Motion correction;    Iron;    Mapping;    Hemochromatosis;    Thalassemia;    Cardiovascular magnetic resonance;   

DOI  :  10.1186/s12968-014-0106-9

 received in 2014-06-26, accepted in 2014-12-29,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundPixel-wise T2* maps based on breath-held segmented image acquisition are prone to ghost artifacts in instances of poor breath-holding or cardiac arrhythmia. Single shot imaging is inherently immune to ghost type artifacts. We propose a free-breathing method based on respiratory motion corrected single shot imaging with averaging to improve the signal to noise ratio.MethodsImages were acquired using a multi-echo gradient recalled echo sequence and T2* maps were calculated at each pixel by exponential fitting. For 40 subjects (2 cohorts), two acquisition protocols were compared: (1) a breath-held, segmented acquisition, and (2) a free-breathing, single-shot multiple repetition respiratory motion corrected average. T2* measurements in the interventricular septum and liver were compared for the 2-methods in all studies with diagnostic image quality.ResultsIn cohort 1 (N = 28) with age 51.4 ± 17.6 (m ± SD) including 1 subject with severe myocardial iron overload, there were 8 non-diagnostic breath-held studies due to poor image quality resulting from ghost artifacts caused by respiratory motion or arrhythmias. In cohort 2 (N = 12) with age 30.9 ± 7.5 (m ± SD), including 7 subjects with severe myocardial iron overload and 4 subjects with mild iron overload, a single subject was unable to breath-hold. Free-breathing motion corrected T2* maps were of diagnostic quality in all 40 subjects. T2* measurements were in excellent agreement (In cohort #1, T2*FB = 0.95 x T2*BH + 0.41, r2 = 0.93, N = 39 measurements, and in cohort #2, T2*FB = 0.98 x T2*BH + 0.05, r2 > 0.99, N = 22 measurements).ConclusionsA free-breathing approach to T2* mapping is demonstrated to produce consistently good quality maps in the presence of respiratory motion and arrhythmias.

【 授权许可】

CC BY   
© Kellman et al.; licensee BioMed Central. 2015