Validation of the Position of Injection Needles with Contrast-Enhanced Ultrasound for Dynamic Contract-Enhanced MR Lymphangiography.

PURPOSE: To assess the feasibility of validating the position of the needle in groin lymph nodes using injection of ultrasound (US) contrast prior to magnetic resonance (MR) lymphangiography.

MATERIALS AND METHODS: In 28 patients (average age, 52 y; 15 women, 13 men), 25G needles were placed in bilateral groin lymph nodes using US guidance outside the MR suite. The confirmation of the position of the needles in lymph nodes and efferent lymphatic flow was performed by injecting 1 mL of the US contrast agent (Lumason) mixed with 2 mL of lidocaine and observing contrast enhancement of the efferent lymphatic ducts leading to the pelvis from the lymph node. The patients were then transferred to the MR suite, and MR lymphangiography was performed.

RESULTS: In 6 patients, the needle was repositioned due to nonvisualization of the efferent lymphatic flow toward pelvis at the first attempt. MR lymphangiogram was then performed in all patients with good opacification of the central lymphatic system. No extravasation of gadolinium contrast agent was observed.

CONCLUSIONS: Injection of US contrast to confirm the position of the needles inside the lymph nodes is a safe and effective technique. This technique can serve as a substitute for fluoroscopic confirmation of needle position, allowing performance of MR lymphangiography on any MR machine with a detachable table.