High Resolution ASL Perfusion Imaging of the Kidneys at 3 Tesla

Purpose: The feasibility of highly resolved arterial spin labeling (ASL) perfusion imaging of the kidneys was tested and proven at 3 Tesla using a flow-sensitive alternating inversion recovery (FAIR) true fast imaging in steady precession (TrueFISP) technique.

Methods: Kidney perfusion maps of six healthy volunteers and two patients were acquired using a clinical 3 Tesla whole-body scanner. An ASL sequence with FAIR spin-preparation and a TrueFISP signal recording strategy was adapted for high-resolution perfusion imaging of the kidneys at 3 Tesla. To avoid banding artifacts in TrueFISP images, which are prominent at 3 Tesla, a frequency scout was implemented. Perfusion maps with an in-plane resolution of 1.5mm were recorded in transverse and coronal orientation. For fast mapping of the whole-kidney perfusion, an in-plane resolution of 2mm was applied.

Results: In all volunteers and patients, highly resolved perfusion images with excellent image quality could be obtained during 9:48 minutes of measuring time. The whole kidney could be mapped in diagnostic image quality in less than 10 minutes. For all slices, a suitable frequency offset provided the kidneys free of TrueFISP artifacts. Perfusion values of the renal cortex ranged from 250 ml/100g/min up to 400 ml/100g/min (mean cortical perfusion right kidney 316±43, left 336±40).

Conclusion: Highly resolved ASL perfusion images of the whole kidney could be obtained with diagnostic image quality by means of a 3 Tesla MR setting within clinically applicable measuring time offering an alternative to conventional perfusion imaging with potentially nephrotoxic contrast-media.