Electronic Posters: Cardiovascular

Human MRA

Hall B Monday 14:00-16:00 Computer 41

14:00 3757. Clinical Evaluation of Peripheral Vascular Disease Using a Hybrid Approach: Unenhanced Quiescent Interval Single Shot and Low-Dose TWIST MR Angiography

Philip Anthony Hodnett^1,2, Ioannis Kokztzoglou³, Timothy Scanlon, Jeremy Collins⁴, John Sheehan, Eugene Dunkle, James C. Carr, Robert Edelman

¹Northwestern University, Chicago, IL, United States; ²Northshore University Healthcare System, Chicago, IL, United States; ³Northshore University Healthcare System, United States; ⁴Northwestern University, United States

Imtroduction:The purpose of this study was to test the hypothesis that a hybrid technique employing a new unenhanced MRA technique, quiescent interval single shot (QISS) in combination with a low-dose time resolved (TWIST)of the calf provides comparable diagnostic accuracy to the standard hybrid approach using low-dose TWIST of the calf and high-dose stepping table CE-MRA. Materials and Methods:20 prospective patients referred for evaluation of peripheral arterial disease underwent unenhanced and combined low-dose time-resolved (TWIST)evaluation followed by standard hybrid stepping table bolus chase MRA. Results:The combined unenhanced QISS technique and low-dose time resolved (TWIST ) calf study resulted in an overall sensitivity of 97.4%, specificity of 98.3%, a negative predictive value of 98.7% and a positive predictive value of 96.7% using CE-MRA as the reference standard. Cohen kappa analysis for inter-rater indicates almost perfect agreement (©§= 0.86) between the hybrid approach of unenhanced QISS and TWIST and standard hybrid CE-MRA. Conclusion: This hybrid strategy permits a dramatic reduction in contrast agent dosage with no loss of diagnostic accuracy.

14:30 3758. "Does Higher R1 Relaxivity Transfer in Improved Vessel Enhancement of the Run-Off Vasculature?" - Evaluation of Macrocylic Gadolinium Chelates for Peripheral MR-Angiography at 3 T by an Inter-Individual Comparison of Gadobutrol Vs Gadoterate Meglumine, Bo

Ulrike I. Attenberger¹, Matthias Voth², Andre Luckscheiter³, Stefan Haneder¹, Stefan O. Schoenberg⁴, Henrik J. Michaely<sup>1

1</sup>Department of Clinical Radiology and Nuclear Medicine, University Medical Center Manheim, Mannheim, Germany; ²Bayer Schering AG, Berlin, Germany; ³University of Heidelberg, Heidelberg, Germany; ⁴Department of Clinical Radiology and Nuclear Medicine, University Medical Center Manheim , Mannheim, Germany

Since nephrogenic systemic fibrosis (NSF) has been linked to gadolinium-chelate administration in patients with impaired renal function, contrast agent dose and chelate stability have attracted broad attention. Numerous studies have demonstrated linear compounds to be the least stable, whereas the macrocyclic compounds are the most stable. With the approval of gadobutrol, a double concentrated macrocyclic gadolinium chelate became available, characterized by the highest R1-relaxivity among the macrocyclic gadolinium chelates. The aim of this study was to evaluate the enhancement characteristics of gadobutrol and gadoterate meglumine, both injected at a dose level of 0.07 mmol/kg BW, for peripheral MR-angiography.

15:00 3759. Non Contrast MRA of the Renal Artery: Comparison of Respiratory Triggered IFIR and ECG Gated IFIR with Autovoice Guidance for Respiration

Takayuki Masui¹, Motoyuki Katayama¹, Kimihiko Sato¹, Hiroki Ikuma¹, M Sugimura¹, M Ishii¹, Naoyuki Takei², Mitsuharu Miyoshi<sup>2

1</sup>Radiology, Seirei Hamamatsu General Hospital, Hamamatsu, Japan; ²Japan Applied Science Laboratory, GE Healthcare Japan, Hino, Japan

Non-contrast (NC) MRAs including inflow inversion recovery (IFIR) FIESTA have shown promising results for demonstration of the renal arteries but might show irregularity in the most peripheral parts of the renal arteries. The purpose was to evaluate effect of autovoice guiding respiratory cycle with ECG gating (IFIR with autovoice) on the quality of NC MRA for demonstration of renal arteries in comparison with contrast MRA. MRA using IFIR with autovoice could provide best image quality of the peripheral renal arteries when autovoice successfully guided respiration. Contrast MRA might miss the optimal timing for selective visualization of the renal arteries.

15:30 3760. Two-Station Time-Resolved 3D Contrast-Enhanced MRA with Real-Time Station Switching

Casey Peter Johnson¹, Clifton R. Haider¹, Eric A. Borisch¹, Roger C. Grimm¹, Phillip J. Rossman¹, Thomas C. Hulshizer¹, Jake C. Snell¹, James F. Glockner¹, Stephen J. Riederer<sup>1

1</sup>Department of Radiology, Mayo Clinic, Rochester, MN, United States

The purpose of this work was to improve bolus-chase MRA techniques by imaging multiple stations with both high spatial and temporal resolution. A highly-accelerated (14x) CAPR acquisition, previously demonstrated for single-station MRA of the calves, was adapted for this purpose. As part of the implementation, a system was developed to reconstruct the CAPR images in real time and allow for visually-guided station switching. Vasculature of the thighs and calves of volunteers was imaged with 1.0 mm isotropic resolution and frame times as low as 2.5 seconds. High-quality arterial frames were consistently acquired in both stations while avoiding venous contamination.