Abstract No. 312 - Initial clinical experience with a quadrupol butterfly coil for spinal interventions in an open vertical MRI at 1.0 Tesla

Abstract

Purpose In vertical open MRI systems, near real-time spinal injection procedures usually need to be performed in lateral decubitus position because the needle artifact is often impaired in prone position. The purpose of this study was to report our initial clinical experience with a coil, allowing for interventions in prone position. Materials and Methods 15 patients (7 women, 8 men; mean age 42 y) were treated in a 1.0 Tesla Panorama High Field Open (HFO) MRI system (Panorama HFO) using a quadrupol butterfly coil (Bfly), and matched by 15 patients of similar sex, age and MR intervention performed in conventional lateral decubitus position with the Multipurpose L coil (MPL; all devices Philips Medical Systems, Best, The Netherlands). A near real time PD TSE image sequence (TR/TE/flip angle/ta: 200-1000ms/5.7- 90ms/90°/3-4.4 s/image) and a MRI-compatible 20-G Chiba needle (10 or 15 cm; Cook [Bloomington, IN]) was used for intervention. Qualitative and quantitative image analysis was performed including signal intensity, SNR, CNR, contrast measurement and Full Width at Half Maximum (FWHM) determination of the needle. Results All 15 interventions (12 lumbar and 1 cervical periradicular, 1 lumbar facet joint and 1 epidural lumbar infiltration) were performed successfully. Subjective image quality and intervention time were comparable to the conventional MR intervention. Quantitative analysis yielded significant results for contrast between the needle and musculature (Bfly 0,27/MPL 0,17) as well as the periradicular fat tissue (0,13/0,24) during the intervention (both, p=0,029). CNR between musculature and needle was significant (10,61/5,23; p=0,010) although FWHM values were not (2,4/2,2; p=0,754). Needle signal intensity during intervention (1152,9/793,2; p=0,006) and post interventional SNR values of subcutaneous fat (15,3/28,6; p=0,007), musculature (6,6/11,8; p=0,011) and CNR between these tissues (8,7/17,5; p=0,004) were statistically significant. Conclusion The new quadrupol butterfly coil is a feasible alternative for MR guided interventions, especially when patients cannot (or prefer not to) be in a lateral decubitus position, or if prone positioning yields better access to the target zone.