Shifted rotated keyhole imaging and active tip-tracking for interventional procedure guidance

The tools and devices used for patient treatment during interventional procedures must be accurately and safely localized. Recently, procedure guidance has been performed increasingly with MRI, but tool localization has been performed primarily by analyzing the lack of signal caused by displaced excited tissue and/or susceptibility artifacts. In this investigation, a new technique was developed to actively detect and visualize interventional tools using receive coils mounted on the tip of the interventional devices. Unlike earlier methods, in which images from small device-mounted coils are superimposed on a previously acquired image data set, our localization method uses similar tip-mounted tools in combination with a radiofrequency (RF) switching circuit, standard imaging coils, and specially modified sequences to toggle between the standard and tipmounted receive coil within a single fluoroscopic mode sequence. With this technique, the misregistration between the reported anatomic location and true location of interventional devices is minimized.