If a suspected cancerous lesion detected on breast MRI cannot be felt by hand and cannot be visualized on mammography or ultrasonography, the biopsy procedure for the lesion in question is performed under MRI guidance. MR-guided thick needle biopsy or lesion wire marking is performed. MRI-guided biopsy is a new procedure and can only be performed in a few centers around the world. Although this biopsy technique is not much different from other biopsy techniques, special MR device, MR compatible biopsy apparatus and needles are used during the procedure.