Shifted rotated keyhole imaging and active tip-tracking for interventionalprocedure guidance

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