Adaptive Prediction of RR interval for online MR parameters changes
Abstract
Cardiac MRI sequences are generally synchronized on the R wave of the ECG and the read out is done in the ventricular iastole. Depending to the heart rate (HR) and so on the RR interval, an optimal trigger delay (TD), an acquisition time (AT) (which is a function of MR parameters) and a trigger window (TW) are defined before scanning. For Black Blood acquisition, IR pulses are currently played directly on the R wave to have an inversion time (TI) of the blood on read out. Unfortunately, physiological changes of the RR timing especially during breath hold make all these fixed timings non optimum. Additionally, optimal TI for complete nulling of wash in blood is not always compatible with HR > 85 bpm. Moreover, if acquisition of systolic phase is desired, these IR pulses have to be place before the current R wave in the preceding heart cycle. We propose a prediction of the next RR duration based on previous RR cycles. The prediction of RR interval will be used to adapt MR timing parameters (TD, TW, TI, AT) during scanning and enable black blood images in the systolic phase.