Free-breathing myocardial T2 measurements at 1.5T
© Lohezic et al; licensee BioMed Central Ltd. 2011
Published: 2 February 2011
Myocardial T2 mapping is a valuable tool for tissue characterization and oedema visualization. For instance, it is used to detect early rejection of heart transplant . T2 values are usually estimated by performing several black blood Fast Spin Echo (FSE) sequences with different Echo Times (TE), what requires multiple breath holds. Successive apneas could lead to misregistration between images and to patient discomfort. A method allowing free breathing myocardial T2 measurements has been recently proposed and evaluated at 3T . Results at 1.5T are presented here.
This study aims at demonstrating the feasibility of free-breathing myocardial T2 mapping at 1.5T.
10 to 75 ms
16 or 24
First, the ten breath-held images were registered manually. Then, the T2 map was obtained using a mono-exponential model to fit the T2 signal versus the echo time decay curve, on a pixel-wise basis.
Free breathing reconstruction
Using physiological signals extracted from the respiratory belt, the method presented in  was used to obtain an artefact-free proton density weighted image r0 and a T2 map from the free breathing raw data set. For the sake of comparison, six segments were drawn on the left ventricle myocardium. The mean value of each ROI was then used to get 6 myocardial T2 values.
The proposed free breathing method allows performing accurate T2 mapping at 1.5T with no additional acquisition time.
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