The invention concerns a medical imaging system comprising means (4) of segmenting a region of interest around an object of interest within a volume of 3D data (3DV). The system according to the invention comprises means (5) of calculating a sub-regions map (CSR) within the segmented region (RS) and correction means (6) intended to exclude sub-regions of the segmented region by means of said sub-regions map (CSR). The correction can be made automatically or manually by means of control means (7) enabling a user to select the sub-regions to be excluded. Display means (3) make it possible to display a 2D representation (2DR) of the volume of 3D data (3DV) and the segmented region (RS, RS&prime) at various stages of the processing.
