[Puncture with an open-sided, interventional MRI system. Illustration with a case report]

A 0.5 T open-configuration MR system allows free access to the patient via a 58-cm-wide opening on both sides of the machine. A newly developed system for needle guidance enables the examiner to perform biopsies in combination with real-time imaging and to position laser fibers in the human body. For imaging, a 2D gradient echo sequence is used (TR 19 ms, TE 9 ms, flip angle 30 degrees FOV 24 x 24 cm, slice thickness 10 mm matrix 256 x 128). The acquired images are displayed on two LCD screens localized within the MR system, thus allowing an interactive needle guidance. This procedure is illustrated by a case report.

The handling of the system for needle guidance was simple, mainly due to a real-time adaption of the scan plane to the needle direction. The possibility of multi-angulated approaches makes biopsies of hardly accessible anatomic regions feasible.

We think that MR-guided needle positioning will play an important role in combination with thermosensitive therapies. Thermosensitivity of MR imaging allows extensive monitoring of such interventions.