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MR angiography with gadopentetate dimeglumine-polylysine: evaluation in rabbits
G Marchal1, H Bosmans, P Van Hecke
1Department of Radiology, University Hospitals K.U. Leuven, Belgium.
Abstract:
Flow in high-resistance peripheral vessels of the extremities is characterized by a short period of positive flow during systole and almost no flow during diastole. Hence, time-of-flight sequences for MR angiography in high-resistance peripheral vessels are successful only when applied in a plane perpendicular to the vessel course. When applied in a plane parallel to the vessel, the method suffers from the rapid saturation of the inflowing spins. Gadopentetate dimeglumine-polylysine is a new T1 relaxation agent with blood-pooling capability that can be used to prevent blood saturation. In the present study it produced excellent angiograms in rabbits at a dose of 0.01-0.08 mmol/kg injected IV. Time-of-flight angiograms were acquired in a 1.5-T superconducting magnet with a three-dimensional fast imaging with steady precession sequence, 20,40/10/20 degrees (TR/TE/flip angle), with an acquisition volume of 200 x 200 x 60 mm, 64 partitions, and velocity compensation in the slice-selection and frequency-encoding directions. Arteries and veins smaller than 1 mm were visualized over the entire length of the posterior limbs. If ongoing studies confirm the low toxicity of this new agent, gadopentetate dimeglumine-polylysine could offer a totally new approach to MR angiography.
Insights
A new contrast agent, gadopentetate dimeglumine-polylysine, improves MR angiography of high-resistance vessels. This blood-pooling agent prevents spin saturation, enabling clear visualization of small arteries and veins in rabbits.
Area of Science:
- Medical Imaging
- Radiology
- Biomedical Engineering
Background:
- Peripheral vascular MR angiography faces challenges due to high-resistance flow patterns.
- Time-of-flight (TOF) sequences are limited by rapid spin saturation in parallel imaging planes.
Purpose of the Study:
- To evaluate the efficacy of gadopentetate dimeglumine-polylysine as a blood-pooling contrast agent for MR angiography.
- To assess the agent's ability to overcome spin saturation in high-resistance vessels.
Main Methods:
- Utilized a novel T1 relaxation agent, gadopentetate dimeglumine-polylysine, with blood-pooling capabilities.
- Acquired 3D fast imaging with steady precession TOF angiograms in rabbits using a 1.5-T magnet.
- Administered the agent intravenously at doses ranging from 0.01-0.08 mmol/kg.
Main Results:
- Achieved excellent angiograms in rabbits, visualizing arteries and veins smaller than 1 mm.
- Demonstrated successful imaging over the entire length of the posterior limbs.
- The agent effectively prevented blood saturation, improving image quality.
Conclusions:
- Gadopentetate dimeglumine-polylysine shows significant promise for enhancing MR angiography in challenging vascular territories.
- Further studies on its low toxicity could establish it as a novel MR angiography approach.