Beat to Beat Management of Heart Cycle Changes for Black Blood Imaging in End-Systolic Rest
Résumé
In cardiac MR imaging, the Double Inversion Recovery Fast Spin Echo (DIR-FSE) sequence [1] (also called “black blood”) enables to suppress the blood signal for an accurate depiction of the myocardium. The inversion time (TI) required to suppress the blood signal is constrained by the T1 of the blood and the repetition time [2]. Since the T1 of the blood is long, the TI should also be long. Usually, the detection of an R-wave is used to trigger the sequence. Consequently, the Trigger Delay (TD), the time between an R-wave and the next echo train, is the same as TI and the acquisition is performed during the mid- diastolic rest. The problem is that the TD is constrained by TI whereas it should only be used to select the cardiac phase to acquire. Moreover, the optimum TI does not necessarily match the mid-diastolic, nor end-systolic cardiac rest period . To overcome these limitations, two methods are proposed to acquire black blood images during the end-systolic rest.