Abstract
Recent improvements
in intravascular magnetic resonance imaging techniques mandate an
accurate method of monitoring the introduction of MR catheter probes
into the vessel of interest.
For this purpose,
a novel imaging protocol and a display method have been designed.
First, a roadmap 3-D image data set with standard pulse sequences
is obtained using an external imaging coil.
Subsequently,
using very narrow rectangular-FOV fast-SPGR, a movie of the percutaneous
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 image unwrapping and for displaying the unwrapped movie frames
on the roadmap image.
In an alternative
protocol, the movie frames in two projection angles were acquired
in an interleaved fashion. Frames were unwrapped and combined with
a 3D roadmap and displayed on an SGI workstation equipped with stereo-vision
goggles. Using these methods, percutaneous catheter placement in
a phantom and a dog was examined.
In conclusion,
a new visualization technique for MR catheter placement is proposed.
Combining this technique with high resolution intravascular MRI
techniques may result in a very useful diagnostic tool for the evaluation
of atherosclerosis and other vessel diseases.
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