Comparison of the iron oxide-based blood-pool contrast medium VSOP-C184 with gadopentetate dimeglumine for first-pass magnetic resonance angiography of the aorta and renal arteries in pigs.

Rationale and Objectives: VSOP-C184 at a dose of 0.045 mmol Fe/kg has been shown to be an efficient blood pool contrast medium for equilibrium magnetic resonance angiography (MRA) that can be administered as a bolus. The present study was performed to determine whether VSOP-C184 is also suitable for first-pass MRA. Materials and Methods: Fifteen MRA examinations at 1.5 T were performed in minipigs using a fast 3D fast low-angle shot (FLASH) sequence (repetition time = 4.5 ms, echo time = 1.7 ms, excitation angle = 25°, matrix 256, body phased-array coil). The citrate-stabilized iron oxide preparation VSOP-C184 was investigated (total particle diameter: 7.0 ′ 0.15 nm; core size: 4 nm) and compared with gadopentetate dimeglumine (Gd-DTPA). The following doses were tested: VSOP-C184: 0.015, 0.025, and 0.035 mmol Fe/kg; Gd-DTPA: 0.1 and 0.2 mmol Gd/kg; n = 3 examinations/dose. Data were analyzed quantitatively (signal enhancement (ENH) and vessel edge definition (VED)) and qualitatively. Results: First-pass MRA using the 3 doses of VSOP-C184 yielded the following ENH: aorta: 9.4 ′ 2.6; 12.31 ′ 1.2; 16.53 ′ 1.7; renal arteries: 7.6 ′ 2.2; 9.9 ′ 1.0; 13.2 ′ 0.5. The values for the 2 doses of Gd-DTPA were aorta: 12.9 ′ 1.0; 16.8 ′ 2.2; renal arteries: 11.2 ′ 1.23; 11.3 ′ 1.7. VED for the 3 doses of VSOP-C184 was aorta: 106.3 ′ 31.0; 135.3 ′ 58.8; 141.3 ′ 71.0; renal arteries: 102.2 ′ 24.3; 146.8 ′ 63.0; 126.9 ′ 37.6 and for the 2 doses of Gd-DTPA, aorta: 157.2 ′ 47.8; 164.2 ′ 36.8; renal arteries: 165.9 ′ 30.4; 170.3 ′ 38.2 respectively. The differences between VSOP-C184 and Gd-DTPA are clinically not relevant and statistically not significant (p ≥.05). Qualitative evaluation of image quality, contrast, and delineation of vessels showed the results obtained with VSOP-C184 at doses of 0.025 and 0.035 mmol Fe/kg to be similar to those of Gd-DTPA at 0.1 and 0.2 mmol Gd/kg. Conclusion: VSOP-C184 is suitable for first-pass MRA at doses of 0.025 and 0.035 mmol Fe/kg and thus, in addition to its blood pool characteristics, allows for selective visualization of the arteries without interfering venous signal.