Magnetic resonance imaging-guided navigation with a thermoplastic shell for breast-conserving surgery

The aim of this study was to evaluate the accuracy of a magnetic resonance imaging (MRI) marking technique with a drape-type thermoplastic shell for planning breast-conserving surgery (BCS).

A prospective review was performed on 35 consecutive patients who underwent MRI in the supine position and used the specified MRI marking technique. Eleven cases underwent pre-operative chemotherapy and 24 cases did not. After immobilizing the breast mound with a drape-type thermoplastic shell, patients underwent MRI, and the location of the lesion was marked on the shell. Resection lines were dyed blue by indigo carmine, which was pushed through the pores of the shell. Specimens obtained during BCS were sliced into 5-mm contiguous sections, and the margin was assessed for each specimen. Cancer foci less than 5 mm from the margin were classified as positive.

Of 35 patients, 33 were included in the analysis; 2 were excluded due to a lack of effect of pre-operative chemotherapy. Of these 33 patients, 25 (75.8%) had negative margins and 7 (21.2%) had positive margins.

Our MRI marking technique may be useful for evaluating the extent of tumors that were determined by MRI alone. Long-term outcomes of this technique should be evaluated further.