Non-contrast myocardial perfusion using a novel 4D magnetic resonance arterial spin labeling technique: initial experience.

The aim of this study is to develop a novel non-contrast 4-dimensional MR arterial spin labeling (4D-ASL) technique (3D acquisition and time) and to investigate myocardial perfusion on healthy volunteers without administration of contrast materials. A non-contrast 4D-ASL technique was developed using the time-spatial labeling inversion pulse (Time-SLIP) to obtain myocardium perfusion of eight volunteers at 1.5 T. The tagging slab was placed on the proximal ascending aorta to invert the blood magnetization and mid-ventricle 3D images at diastolic phase were acquired with multiple tagging delays. The time resolved 3D images with various inversion times (TI) were registered and segmented for the visualization of myocardial signal changes along the TI, and perfusion curves were generated to identify the perfusion peaks. Blood flow from basal to apical slices was observed in all volunteers. Peak flow at the mid-ventricle was observed 200-400 ms after the blood was tagged at the aortic root blood. After the perfusion peak, all signals returned to the base line. The 4D Time-SLIP technique permits non-contrast perfusion images with high temporal resolution, which may potentially differentiate normal from diseased myocardium.