Thomas C. Lauenstein MD, Presenter: Nothing to Disclose

Anja Fischer MD, Abstract Co-Author: Nothing to Disclose

Michael Forsting MD, Abstract Co-Author: Nothing to Disclose

Mark E. Ladd PhD, Abstract Co-Author: Nothing to Disclose

Stefan Maderwald PhD, MSc, Abstract Co-Author: Nothing to Disclose

Lale Umutlu MD, Abstract Co-Author: Consultant, Bayer AG

With recognition of a potential side effect, by the name of Nephrogenic Systemic Fibrosis, there has been a shift towards MR angiography techniques with reduction or complete omission of Gadolinium-based contrast agents. Hence, the aim of this trial was to compare the diagnostic ability of non-enhanced (TOF) versus ultra-low-dose contrast-enhanced renal MRA at 7 Tesla.

12 healthy subjects were examined on a 7T MR system (Magnetom 7T), utilizing a custom-built 8-channel RF body coil. Time-of-flight (TOF) MRA was obtained  with a voxel size of 1.0 x 2.0 x 2.5 mm3. Corresponding ultra-low-dose contrast-enhanced (ce) 3D FLASH datasets were acquired with a voxel size of 1.0 x 1.5 x 1.0 mm3, obtained in unenhanced and in arterial phase after the application of 0.025 mmol/kg BW Gadobutrol (Bayer Healthcare). Image subtraction was performed subsequently. Contrast ratios (CR) were measured in the corresponding datasets in the aorta and both renal arteries in correlation to adjacent psoas major muscle. Qualitative analysis with regard to delineation of the renal arterial vasculature was performed by two radiologists using a five-point-scale (5=excellent to 1= non diagnostic).

Both MRA techniques offered a robust and homogenous hyperintense vessel signal of the assessed vasculature. Qualitative analysis revealed comparable results of vessel conspicuity in subjective ratings for TOF MRA (mean left renal artery = 4.5) and subtracted contrast-enhanced datasets (mean left renal artery = 4.6). Background suppression in subtracted datasets was superior to background suppression of TOF-images, reflected in superior contrast ratio values for subtracted datasets (mean aorta =0.7) compared to TOF-MRA (mean aorta = 0.4).

Our results demonstrate the successful facilitation and comparable diagnostic ability for vessel assessment in TOF-MRA and ultra-low-dose renal MRA at 7T, while preserving high quality vessel assessment.

Preservation of high-quality vessel assessment while facilitation of significant reduction, or respectively complete omission of contrast agent, may be of high diagnostic value for MR angiographic examinations in patients with renal insufficiency.

Lauenstein, T, Fischer, A, Forsting, M, Ladd, M, Maderwald, S, Umutlu, L, Non-enhanced (TOF) MRA versus Ultra-low-Dose Contrast-enhanced MRA at 7T.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018938.html