Abstract: Image guidance on a computer screen in the patient's vascular system with reduced use of toxic contrast agent and X-ray radiation is obtained by providing anatomical and functional images obtained preferably from an MR Imaging system. A fibre optic device which uses strain measurement to provide an image of the shape and location of the fiber is used to provide spatial information of the elongate guide member as it is pushed through the vascular system with this spatial information being registered to the image of the vascular system by registering the location of the fiber/guide in the image prior to insertion using markers visible in the MR image.