Abstract: A system for localizing tissue in a single MRI session is disclosed. The system comprises an MRI compatible localizing obturator selectively insertable through the working channel of an introducer cannula or sheath and configured for insertion through a tissue pathway to a target tissue site. The obturator includes an elongate shaft having open proximal and distal ends and an inner lumen extending between the open proximal and distal ends. At least one MRI image-enhancing component is disposed on and/or within the distal end of the obturator. The system further includes an MRI compatible localizing wire slidable within the inner lumen of the obturator. The wire defines an elongate body having first and second ends and an anchoring member adjacent to one of the first and second ends, the anchoring member adapted to engage tissue so that the wire remains in the patient upon removal of the obturator.