Combined respiratory and cardiac triggering improves blood pool contrast-enhanced pediatric cardiovascular MRI.

BACKGROUND: Contrast-enhanced cardiac MRA suffers from cardiac motion artifacts and often requires a breath-hold.
OBJECTIVE: This work develops and evaluates a blood pool contrast-enhanced combined respiratory- and ECG-triggered MRA method.
MATERIALS AND METHODS: An SPGR sequence was modified to enable combined cardiac and respiratory triggering on a 1.5-T scanner. Twenty-three consecutive children referred for pediatric heart disease receiving gadofosveset were recruited in HIPAA-compliant fashion with IRB approval and informed consent. Children underwent standard non-triggered contrast-enhanced MRA with or without suspended respiration. Additionally, a free-breathing-triggered MRA was acquired. Triggered and non-triggered studies were presented in blinded random order independently to two radiologists twice. Anatomical structure delineation was graded for each triggered and non-triggered acquisition and the visual quality on triggered MRA was compared directly to that on non-triggered MRA.
RESULTS: Triggered images received higher scores from each radiologist for all anatomical structures on each of the two reading sessions (Wilcoxon rank sum test, P < 0.05). In direct comparison, triggered images were preferred over non-triggered images for delineating cardiac structures, with most comparisons reaching statistical significance (binomial test, P < 0.05).
CONCLUSION: Combined cardiac and respiratory triggering, enabled by a blood pool contrast agent, improves delineation of most anatomical structures in pediatric cardiovascular MRA.