Triggering in quantitative diffusion imaging with single-shot EPI

Purpose: The aim of this study was to evaluate any possible effects of brai n motion, CSF pulsations and other possible sources of physiological motion in electrocardiographic (ECG) triggered and non-triggered single-shot echo -planar imaging (EPI) measurements of diffusion. Material and Methods. Three different triggering protocols were evaluated i n 6 healthy volunteers: 1) ECG triggering with time delay (TD) 100 ms; 2) E CG triggering with TD 400 ms; and 3) no triggering at all. Results: The results obtained showed that white matter mean apparent diffus ion coefficient (ADC) values were similar for all triggering protocols and that the reproducibility in ADC measurements using diffusion-weighted (DW) EPI was good. The average standard deviation of the ADC values was, however , higher for ADC maps obtained without ECG triggering. Conclusion: The use of prospective diastolic ECG triggering significantly i mproves the accuracy of quantitative diffusion measurements but for routine clinical diffusion imaging, where quantitative data is of less importance, the accuracy obtained without ECG triggering can be considered adequate.