Development of Intravascular MRI Probe Applicable to Catheter Mounting

Abstract

This paper reports the concept and fabrication techniques of high-resolution intravascular magnetic resonance imaging (MRI) probes. A receiver coil placed in the luminal tissues such as vessels may sensitively detect the signal from the surrounding tissue to produce high-resolution intravascular images. The intravascular MRI offers great potential for in vivo diagnosis of vascular diseases, therapeutic planning, and therapeutic effect evaluation. An ideal intravascular receiver coil should have homogeneous and high signal-to-noise ratio around the coil, tightly placed tuning/matching circuits, and a large working channel for a medical device such as a catheter used as a substrate. In this study, multilayer and/or three-dimensional photolithography techniques were used for fabricating a receiver coil on cylindrical substrates. A coil has been fabricated on a glass capillary with 2 mm outer diameter. The coil was connected to tuning/matching capacitors and decoupling pin-diodes. Imaging of a vessel wall and a phantom with 2-mm pitch acrylic lattice were performed on a 1.5-T MRI scanner resulting in 7.5-mm imaging region. The probe coil was then applied to a vessel wall sample resected from a porcine subclavian artery. The results successfully demonstrated the usefulness of the probe coil for high-resolution intravascular imaging.