Breath‐Hold 3D STAR MR Angiography of the Renal Arteries Using Segmented Echo Planar Imaging

Abstract

Three-dimensional (3D), cardiac triggered renal MR angiograms were acquired with excellent background suppression within a single breath-hold of 18 to 30 s using signal targeting with alternating radiofrequency (STAR), a subtraction time-of-flight MR angiography technique, and a 3D scheme combining echo planar imaging (EPI) readouts and k-space segmentation. The 3D STAR sequence was evaluated on 17 healthy individuals, 3 potential renal donors, and 2 patients with suspected renovascular hypertension. An inversion tag through the aorta was applied to produce the vascular contrast. After a suitable inflow time, 16 to 64 sections were encoded. An additional presaturation pulse applied over the imaging volume prior to tagging permitted improved background suppression by reducing signal variations from involuntary motion and changes in the cardiac period during breath-holding. Intrarenal branches were observed consistently in all healthy individuals. Longer inflow times provided better depiction of the intrarenal vessels while shorter delays delineated the proximal renal branches with better signal-to-noise ratio. Breath-hold and diastolic data collection reduced both blurring and flow related dephasing. Our results demonstrate excellent visualization of the renal arteries to the level of intrarenal branch vessels using the proposed technique.