MR-guided joint puncture and real-time MR-assisted contrast media application.

OBJECTIVE

To develop, in MR arthrography of the shoulder joint, an MR-guided technique for localizing the needle puncture and confirming the intracapsular needle-tip position by visualization of the contrast media inflow.

MATERIAL AND METHODS

Three unfixed human shoulder specimens were examined on a 1.0 T MR unit. On the basis of MR-compatible markers, the optimal entrance point for puncturing the joint was determined. The precise localization of the needle tip (MR-compatible 0.7-mm needle) in the shoulder joint was determined with rapid localizer GRE sequences in 2 orthogonal planes. To confirm the intracapsular position of the needle tip, diluted Gd-DTPA was applied via a long connecting tube and contrast medium inflow into the joint space was controlled on an LCD screen in real-time MR imaging (local-look technique).

RESULTS

MR-compatible markers on the skin allowed the rapid determination of the optimal entrance point for needle puncture. An adequate localization of the intra-articular needle-tip position was possible in all specimens although significant artifacts were present on rapid localizer GRE sequences which resulted in an increase in the apparent width of the needle shaft. Real-time MR imaging of the contrast medium inflow was made possible by the local-look technique and LCD screen on the MR unit and this allowed confirmation of the intracapsular position.

CONCLUSION

In MR arthrography of the shoulder, an MR-guided technique in conjunction with the LCD screen and real-time MR imaging would seem to be a practical alternative to conventional fluoroscopic guidance.