Five healthy volunteers underwent cardiac examination at 1.5T (SIGNA HDxt, GE Healthcare, Milwaukee, WI). Two sets of ten images with different TE were acquired with a conventional cardiac-gated black blood FSE sequence at mid-cavity short axis view, one during breath hold and the other one during free breathing. The same parameters were used, except for echo train length (ETL) (Table 1).ETL was set at 24 to keep the breath hold duration short, whereas 16 echoes were used for free-breathing acquisitions. Raw data from the free breathing acquisitions were recorded. Signals from a respiratory belt were carried by a custom Maglife patient monitoring system (Schiller Medical, France) and recorded with a dedicated home-made hardware 3 .

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.

Using physiological signals extracted from the respiratory belt, the method presented in 2 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.