MR-guided interventions at 0.23T : facilities, user interface, guiding technology and musculoskeletal applications

Abstract

<div lang="en" class="abs"><p class="abs_header">Abstract</p><p>Magnetic resonance imaging (MRI) has excellent soft tissue contrast, which can be enhanced by different contrast agents, multiplanar imaging capability and high temporal and spatial resolution. Even blood vessels can be easily visualised, and MRI parameters are sensitive to temperature. Therefore, MRI has the greatest potential for guiding and monitoring interventional and surgical procedures.</p><p>The aim of this study was to design and evaluate new solutions for MR-guided procedures and surgery, to develop the technique and to assess the feasibility of MR-guided nerve root infiltration, bone biopsy and sacroiliac (SI) joint arthrography.</p><p>The possibilities for versatile use of MR scanners were studied with a setup where an MR scanner with a 0,23 T open magnet was installed in a full-scale operating room (OR) to allow diagnostic MRI examinations, research, radiological interventions and neurosurgical operations to be performed in the same facility. All of the 144 MR-guided radiological interventions and neurosurgical operations performed in Oulu University Hospital between February 1999 and September 2000 were included in the study. The studied setup was a functionally feasible solution for combined neurosurgical and radiological use.</p><p>To further improve MR-guided interventions, a new user interface was developed and preliminary tested with simulated clinical experiments. The new user interface seemed to be easily adobted by radiologists for interventional procedures.</p><p>MR-guided nerve root infiltrations were studied by using MRI guidance on 34 consequent patients referred for first sacral root infiltration. Needle placement into the first sacral nerve root sheath was successful in 34 of the 35 (97%) cases, and the average duration of the procedure was 32 minutes.</p><p>Bone biopsies were performed using a bone biopsy set designed in our institution to be connected to an optical tracking system. The feasibility of this new guiding system was evaluated with biopsies from five different anatomical areas. The bone biopsy system was successfully applied to all patients and provided a safe and accurate guidance method for all phases of the procedure.</p><p>Twenty patients with low back pain suspected to arise from the SI joint underwent MR-guided SI joint arthrography. The procedure was successfully performed in all cases. The needle guiding with optical tracking inside the soft tissues proved to be accurate enough for successful procedures.</p><p>In conclusion, versatile use of MR scanners for diagnostic imaging, radiological procedures and neurosurgery is feasible if planned properly. The prototype of a new user interface for MR-guided procedures allows radiologist to fully control the MR-scanner during the procedure. MRI is a suitable and accurate guidance method for musculoskeletal interventions.</p></div>