72197 - Evaluating MRI artefacts and skin discoloration using an intradermal ultra-low dose of superparamagnetic iron oxide for sentinel lymph node detection
Nushin Mirzaei, Fredrik Wärnberg, Pontus Zaar, Micael Oliveira Diniz, Andreas Karakatsanis, Henrik Leonhard, Roger Olofsson BaggeAbstract
Introduction
Superparamagnetic iron oxide (SPIO) nanoparticles is non-inferior as a tracer for sentinel lymph node detection in patients with breast cancer compared to the standard radioactive tracer with or without blue dye. Sentinel lymph node biopsy has been successful using an ultra-low dose of 0.1 mL SPIO injected intradermally in patients with breast cancer, and this study aims to assess the potential reduction of SPIO-related skin discoloration and breast magnetic resonance imaging (MRI) artefacts at 6 and 12 months after breast conserving surgery using an ultra-low dose of SPIO.
Method
Skin discoloration and MRI artefact were pre-planned endpoints in the prospective MAGSNOW feasibility study. MRI follow-ups were scheduled 6 and 12 months after surgery, and MRI artefacts were classified in six grades. SPIO-induced skin discoloration was assessed at baseline, 1, 6 and 12 months by photography.
Result
Thirty-seven out of fifty patients underwent 6 and 12 months MRI follow-ups, revealing no MRI artefacts impairing breast assessment. At 12 months, twenty-seven (73.0%) patients had minimal MRI artefacts, primarily in the subcutaneous tissue, or less than 5 mm in the fibroglandular tissue. Additionaly, at 12 months, twenty-seven out of fifty (54%) patients had a skin discoloration with a median area of 0.79 cm2 (IQR 0.14-1.41).
Discussion
An ultra-low dose of SPIO may offer a solution to the concerns of MRI artefacts and skin discoloration associated with the present recommended dose of 1-2 mL of SPIO. However, these findings have to be confirmed in a larger trial.