MR imaging guided percutaneous nephrostomy using a 1.0 Tesla open MR scanner

The purpose of this study was to assess the safety and feasibility of MR-guided percutaneous nephrostomy (PCN) using a 1.0 Tesla open MR-scanner with fast dynamic imaging.

Twenty-five patients with failed ultrasonographic insertion due to various reasons, such as nondilated pelvic systems, obesity, and parapelvic cysts, were investigated.

In summary, 35 nephrostomy procedures were performed; 15 patients received monolateral and 10 patients bilateral placement. For guidance and monitoring, fast T2w single-shot-TSE imaging in a fluoroscopic mode in two orthogonal planes was used to guide the insertion of the needle into a predetermined calyx in freehand technique. Nephrostomy was inserted via Seldinger-technique. The procedure was regarded as technically successful if the placement of the catheter provided adequate drainage of the collecting system. Demonstration of an intrapelvic position of the catheter was verified by antegrade pyelography using T1w GRE imaging after injection of diluted Gd-DTPA into the collecting system. Under the experimental conditions of the study, the time for the complete procedure was 30 (range, 23-39) min. Puncture and placement of the nephrostomy was performed in 5 (range, 3-10) min on average.

Our results demonstrated a pinpoint puncture of the pelvic system in a reasonable timeframe even in patients with difficult conditions, suggesting that MR-guided PCN using the open 1 Tesla system can be assessed as a reliable, fast, and safe method applicable in the clinical routine setting.