INTERVENTIONAL MR-IMAGING - DEMONSTRATION OF THE FEASIBILITY OF THE OVERHAUSER MARKER ENHANCEMENT (OMEN) TECHNIQUE

Purpose: The poor localization facility of interventional instruments in MK imaging has been one of the major obstacles to the popularizatio n of interventional MR imaging. It has been suggested that the Overhau ser enhancement be used to generate markers of small size and high vis ibility. This article studies the feasibility of a localization marker based on this method. Material and Methods: A small Overhauser marker was constructed on the tip of a coaxial cable and comparative images were taken by a 0.23 T imager with and without electron spin irradiati on. Results: During irradiation an enhanced signal intensity from the marker was observed. The signal from the marker also exceeded the sign al from a 0.25 mmol MnCl2 reference phantom. Conclusion: Its small siz e and high signal-to-noise ratio, together with immunity to most syste m nonlinearities and imaging errors, makes the Overhauser marker a pro mising localization method for the accurate positioning of interventio nal devices. The method may be applied at any field strength, and mark ers are visible in images obtained with any practical imaging sequence .