Sensitivity of arterial spin labeling perfusion MRI to pharmacologically induced perfusion changes in rat kidneys

Abstract

Purpose To investigate whether arterial spin labeling (ASL) MRI is sensitive to changes by pharmacologically induced vasodilation and vasoconstriction in rat kidneys. Materials and Methods Changes in renal cortical blood flow in seven rats were induced by Adenosine infusion (vasodilation) and L-NAME injection (vasoconstriction). All imaging studies were performed on a 3T scanner using a FAIR-TrueFISP sequence for the ASL implementation. The acquisition length for each ASL scan was 6 minutes. Cortical perfusion rates were calculated using regions-of-interest analysis, and the differences in perfusion rates during baseline, vasodilation, and vasoconstriction were compared and assessed for statistical significance. Results Compared to the baseline, an average of 94 mL/100g/min increase and 157 mL/100g/min decrease in cortical perfusion was observed following adenosine infusion and L-NAME administration respectively. The changes in cortical perfusion were significant between baseline and vasodilation (p < 0.05), baseline and vasoconstriction (p < 0.01), and vasodilation and vasoconstriction (p < 0.01). Conclusion ASL is sensitive to pharmacologically induced perfusion changes in rat kidneys at doses comparable to current use. The preliminary results suggest the feasibility of ASL for investigating renal blood flow in a variety of rodent models.

Single-dose diclofenac in healthy volunteers can cause decrease in renal perfusion measured by functional magnetic resonance imaging†

“…Using ASL for the quantification of transient changes of renal cortical perfusion after the application of diclofenac was feasible in our study. This is in line with previous pharmacological studies, using ASL to monitor changes of renal perfusion after pharmacologically induced vasodilatation and vasoconstriction in rats [43] and after application of furosemide in healthy human participants. [44] Furthermore, we could show an excellent inter-reader reproducibility when two independent readers analysed ASL maps, underlining the robust aspect of the method used for data analysis.…”

Motion-corrected multiparametric renal arterial spin labelling at 3 T: reproducibility and effect of vasodilator challenge

“…Otherwise, if quantitative values are reported reference ranges obtained from healthy volunteers at each imaging centre may be necessary [32]. Previous studies have shown the sensitivity of ASL to map dynamic changes in renal perfusion during administration of adenosine [33], protein load [34] and furosemide [35]. GTN is known to be a potent venodilator with the acute effect mainly being a reduction of systolic blood pressure due to an increase in arterial compliance and a decrease in venous return resulting in reflex tachycardia [36].…”

Renal Arterial Spin Labeling Magnetic Resonance Imaging

“…ASL was able to monitor perfusion alterations induced by administration of vasoactive drugs [37], protein loading challenges [30] and furosemide [38]. …”