Angiografía no contrastada con "Arterial Spin Labeling"

Abstract

Abstract. Introduction: Non-contrast magnetic resonance angiography using “Arterial Spin Labeling” (MRA ASL) is a technique designed to label blood spins and therefore create an endogenous contrast suitable for selectively evaluating vascular territories without intravenous contrast (Gadolinium compounds). Methodology: Technical details and results of the implementacion of the MRA ASL using 1.5 and 3.0 Tesla systems in healthy volunteers is described. Results: Two cases were observed: for the angiographic technique of the first case (ASL “Flow-in”) in a 3.0 T unit, cardiac synchronization (cardiac gating), a 3D b-SSFP sequence, and an inversion pre-pulse was used, the latter to saturate the static tissues. The examination volume was located in the axial plane taking care to cover the renal vascular anatomy, which is achieved in most cases with 60 to 70 2 mm slices overlapped in 50%, voxel of 2x1x1 mm and a field of vision (FOV) of 250 x100 mm. The protocol for the second case was obtained on a 1.5 T system, without cardiac gating, with a diaphragmatic respiratory navigator and a 3D Turbo SE coronal sequence after applying two pre-pulse blood saturation bands, the first similar to the previous case and the second, or selective pulse, to label the flow of the vessel of interest. With this method (ASL “Flow-Out”) only the labeled blood emits a signal. Discussion: 3D b-SSFP and 3D Turbo SE non-contrast angiography techniques with ASL pre-pulses in 1.5 and 3T are available alternatives and, therefore, can be considered as a complement to other methods of magnetic resonance angiography when assessing vascular pathology.Keywords: ASL “Arterial Spin Labeling”, MRA ASL “Flow-in”, MRA ASL “Flow-Out”, Non-contrast angioresonance, Magnetic resonance.