First-pass renal perfusion imaging using MS-325, an albumin-targeted MRI contrast agent

RATIONALE AND OBJECTIVES. MR angiography is proving to be a useful clinical study for the diagnosis of vascular disorders of renal arteries. However, its utility in terms of stenosis characterization is still limited, Renal perfusion could provide supplemental information that could allow for a comprehensive evaluation of renal artery stenosis by MR imaging. METHODS. MS-325 is a small-molecule blood pool agent that reversibly binds with serum albumin and hence leads to higher relaxivity and longer residence times in the blood. In this study, the authors evaluated the use of MS-325 to perform first-pass perfusion imaging and contrast-enhanced AIR angiography in the characterization of renal artery stenosis in an animal model. RESULTS. Quantitative perfusion estimates were obtained in the renal cortex (258 +/- 19.8 mL/min/100 g) and are comparable to microsphere measurements (198 +/- 12.2 mL/min/100 g), given the practical constraints, Based on these measurements, perfusion showed minimal changes even when the diameter reductions reached 75%. CONCLUSIONS. MS-325 could provide quantitative perfusion estimates that when combined with MR angiography may lead to comprehensive evaluation of renal artery stenosis.