The Representation of the Breast on the Somatosensory Cortex After Autologous Breast Reconstruction Using 7 Tesla Functional MRI.

Rationale: To study the effects of mastectomy and autologous breast reconstruction on the sensation of the (reconstructed) breast, not only the peripheral reinnervation of the breast should be studied, but also the changes that take place in the somatosensory cortex. Now that the region of interest in the brain and the somatotopy of the non-operated breast are known, studies with patients who underwent mastectomy and breast reconstruction are the next step to understand the neuroplasticity of the brain following breast surgery.

Objective: To study the neuroplasticity of the brain after mastectomy and breast reconstructive surgery by assessing the somatotopy of the breast on the somatosensory cortex of patients who underwent either breast reconstruction with and without nerve restoration or mastectomy without breast reconstruction.

Study design: A single center imaging study carried out in Maastricht University Medical Center.

Study population: A total of 30 female breast cancer patients who underwent a unilateral mastectomy without breast reconstruction or a mastectomy followed by a unilateral autologous breast reconstruction with a deep inferior epigastric artery perforator (DIEP) flap will be included in this study. Three groups of patients will be selected and compared: ten patients who underwent a mastectomy without breast reconstruction, ten patients who underwent a DIEP flap breast reconstruction with sensory nerve restoration of the flap and ten patients who underwent a DIEP flap without nerve restoration.

Intervention: Every subject will undergo a single functional MRI scan in a 7 Tesla MRI scan at least six months after the operation. A scanning session takes approximately 75 minutes. During the scan, piezo-electric stimulators are applied to both the reconstructed and non-operated breast in a fixed pattern. These stimulators stimulate the skin and sensory nerves of the breast and nipple-areola complex in a random sequence.

Main study parameters: The hemodynamic response after stimulation of the skin of the breast and nipple-areola complex, representing neuronal activity in that region, is measured. Within the somatosensory cortex (S1 and S2), the temporo-spatial brain activity patterns after the various stimulation conditions are assessed, and the representation of the breast on the somatosensory cortex is mapped.