Non-contrast renal artery MRA using an inflow inversion recovery steady state free precession technique (inhance): Comparison with 3D contrast-enhanced MRA

Purpose: To assess the performance of a three-dimensional (3D) non-contrast respiratory-triggered steady state free precession (SSFP) pulse sequence for detection of renal artery stenosis. Materials and Methods: A total of 64 patients who had non-contrast MR angiography (NC MRA) and 3D contrast-enhanced MRA (CE MRA) performed during the same exam and three patients who had NC MRA followed by conventional catheter angiography within one month of the MRI exam were included in this retrospective study. Two blinded readers evaluated NC MRA images for the presence of significant renal artery stenosis and also rated their diagnostic confidence and evaluated the images for artifact. A similar analysis was performed for CE MRA images by two additional blinded readers, and discrepancies were resolved by consensus reading. Results: The 67 patients had 168 main and accessory renal arteries, with significant (>50%) stenosis in 34 arteries on CE MRA or conventional angiography. The two NC MRA readers had sensitivity and specificity for detection of significant stenosis of 94%/82% and 82%/87% respectively on a per renal artery basis. Conclusion: There was good agreement between CE MRA and NC MRA for detection of significant renal artery stenosis. This technique should prove useful in evaluating patients with suspected renovascular hypertension who are unable to undergo CE MRA.