J.H. Seppenwoolde, L.W. Bartels, R. van der Weide, J.F.W. Nijsen, A.D. van het Schip & C.J.G. Bakker
PURPOSE: To demonstrate the feasibility of hepatic catheterization for selective delivery of therapeutic agents using a clinical MRI scanner for real-time image guidance.
MATERIALS AND METHODS: Experiments were performed in three domestic pigs (70-80 kg) using a clinical 1.5-T MR scanner. After abdominal three-dimensional contrast-enhanced MR angiography (3D-CE-MRA) was performed, endovascular devices with susceptibility markers were tracked with passive tracking techniques. Catheters were maneuvered into the primary and secondary hepatic arteries. Selective catheterization was verified using selective time-resolved CE angiography. Paramagnetic microspheres were administered to a different region for each liver. The resulting biodistributions were investigated using MR images.
RESULTS: Successful selective hepatic catheterization was repeatedly demonstrated using passive tracking techniques. 3D-CE-MRA significantly aided the interventional procedure by showing the vascular anatomy, and maximum-intensity projections (MIPs) were used as roadmaps during the interventions. In all cases, microspheres were successfully delivered to the selected regions. The catheters were visualized at a maximum frame rate of five frames per second, allowing a good depiction of the devices and a reliable catheterization of the hepatic arteries.
CONCLUSION: Fully MR-guided real-time navigation of endovascular devices permits complex procedures such as selective intra-arterial delivery of therapeutic agents to parts of the liver.