Jacob Agris1, Neda Rastegar2, Kelly Fabrega-Foster2, Sheela Agarwal1,3, Daniel Haverstock4, and Ihab Kamel2
1Radiology, Bayer, Whippany, NJ, United States, 2Radiology, Johns Hopkins, Baltimore, MD, United States, 3Radiology, Massachusetts General Hospital, Boston, MA, United States, 4Statistics, Bayer, Whippany, NJ, United States
Synopsis
International, multicenter phase 3 blinded study comparing
the performance of CE-MRA with Gadobutrol, a high relaxivity and highly stable
macrocyclic contrast agent, to 2D Time-of-flight MRA (ToF) using CTA as the
standard of reference (SoR). 317 patients suspected of renal artery disease were
enrolled. There was almost no error in the Gadobutrol MRA vessel measurements
(0.0mm Gadobutrol vs 0.5mm ToF for stenosis measurements) and superior
assessability as well as superior specificity was demonstrated reducing the need for additional
imaging studies by 50%. Gadobutrol enhanced MRA of the renal arteries has
superior visualization, more accurate measurements and is a valuable
alternative to CTA without any ionizing radiation.Purpose:
The purpose of the study was to compare the performance of a
CE-MRA with Gadobutrol, a high relaxivity and high stability macrocyclic agent, to 2D Time-of-flight
MRA (ToF) using CTA as the standard of reference (SoR). Some key primary
objectives were to evaluate the superiority for structural delineation and
non-inferiority for diagnosis of clinically significant vascular disease
(50-99% stenosis).
Materials and Methods:
317
patients (mean age 55, 54% male) suspected of renal artery disease underwent
MRA with Gadobutrol at a dose of 0.1 mmol/kg power injected at 1.5cc/sec and ToF as well as CTA and were scanned
with 1.5T MRI equipped with at least a 6 element body coil. The evaluations were based on central blinded
read (BR) by 3 different readers for the MRA and CTA and investigator based site reads of the 3 segments for each renal artery.
Exact stenosis and corresponding normal vessel measurements were performed.
Results:
Gadobutrol-enhanced MRA demonstrated statistically significant
improvement in visualization of vascular segments when compared to ToF 95.9% vs
77.6% (P < 0.0001).
In the BR, non-inferiority for sensitivity was shown for Gadobutrol-enhanced
MRA (CE-MRA) compared to ToF MRA (53.4% vs. 46.6% ) as well as superiority for
specificity (94.8% vs.85.7%), taking into account the assessability. The sensitivity improved by 6.8% with CE-MRA
and exceeded 50% but with a 95% confidence interval from 46.2% to 63%. The
corresponding values for the site evaluation were 70% sensitivity for CE-MRA
and 49.3% for ToF MRA and 96.5%
specificity for CE-MRA vs. 83.4% ToF MRA.
There was almost no error in the Gadobutrol-enhanced MRA vessel
measurements (0.0mm Gadobutrol vs 0.5mm ToF for stenosis measurements).
In addition, FMD was diagnosed more frequently and more accessory
renal arteries were identified with Gadobutrol-enhanced MRA and diagnostic confidence
increased and fewer additional imaging studies were recommended.
Conclusion:
Gadobutrol
enhanced MRA was superior to 2D ToF MRA for delineation of the vascular
segments as well as exclusion of disease. Furthermore it showed high accuracy
with minimal error in the vascular measurements (Fig 1). Gadobutrol enhanced MRA
of the renal arteries has superior visualization, more accurate measurements
and is a valuable alternative to CTA without any ionizing radiation.
Acknowledgements
No acknowledgement found.References
No reference found.