CATHETER-TRACKING FOV MR FLUOROSCOPY

Recent improvements in intravascular magnetic resonance imaging techni ques mandate an accurate method of monitoring the introduction of MR c atheter probes into the vessel of interest. For this purpose, a novel imaging protocol and a display method have been designed, First, a roa dmap 3D image data set with standard pulse sequences is obtained using an external imaging coil. Subsequently, using very narrow rectangular -FOV fast-spoiled gradient recalled (SPGR), a movie of the percutaneou s placement procedure of an MR catheter probe is acquired at a rate of 7.3 frames/second. In this protocol, the probe is used to transmit RF pulses and receive MR signal. A computer program was written for imag e unwrapping and for displaying the unwrapped movie frames on the road map image. In an alternative protocol, the movie frames in two project ion angles were acquired in an interleaved fashion. Frames were unwrap ped and combined with a 3D roadmap and displayed on a Silicon Graphics workstation equipped with stereovision goggles. Using these methods, percutaneous catheter placement in a phantom and a dog was examined. I n conclusion, a new visualization technique for MR catheter placement is proposed. Combining this technique with high resolution intravascul ar MRI techniques may result in a very useful diagnostic tool for the evaluation of atherosclerosis and other vessel diseases.