MULTIPLE BREATHHOLD 3D TIME-OF-FLIGHT MR-ANGIOGRAPHY OF THE RENAL-ARTERIES

A technique is described for angiographic imaging of the renal arterie s with acquisition performed over several periods of suspended respira tion, The 3D Fourier transform (FT) gradient-echo angiographic sequenc e uses magnetization preparation and appropriately chosen delay times for background nulling and time-of-flight enhancement of the vasculatu re, The sequence was applied to 10 volunteers, each of whom was imaged in three ways: (i) over a series of breathholds in which feedback was provided to enable reproducible breathholding; (ii) over a series of breathholds with no feedback; and (iii) over continuous respiration, R esults were evaluated by measuring the transverse extent of the well-d elineated renal vasculature and by noting the distal extent of the vas culature branching (main, segmental, and interlobar branches), The tra nsverse extent of renal vasculature visible with breathhold feedback, breathholding, and free breathing was 6.1 +/- 0.9 cm, 5.0 +/- 1.8 cm, and 4.0 +/- 1.4 cm, respectively (mean +/- SD). Breathhold feedback en abled visualization of segmental renal arteries bilaterally in all 10 volunteers.