Miniature self-contained intravascular magnetic resonance (IVMI) probe for clinical applications

A miniature (1.73 mm in diameter) NMR probe, which contains a magnet and a radiofrequency (RF) coil, is presented. This probe is integrated at the tip of a standard catheter and can be inserted into the human coronary arteries, creating local magnetic fields needed to obtain the NMR signal from the blood vessel walls, without the need for external magnet or RF coils. The basic theory governing the probe performance in terms of signal-to-noise-ratio and contrast parameters is presented, along with measured results from test samples. The NMR signal can be analyzed to obtain tissue contrast parameters such as T ₁, T₂ and the diffusion coefficient, which may be used to detect lipid-rich vulnerable plaques in the coronary arteries.