In a method and apparatus for the three-dimensional presentation of an examination region of a patient in the form of a 3D reconstruction image, a preoperatively acquired 3D image dataset of the examination region is employed in a medical procedure, datasets representing a number of 2D ultrasound images of the examination region are acquired, the preoperative 3D image dataset is updated using the datasets representing 2D ultrasound images, and the 3D reconstruction image is generated on the basis of the updated 3D image dataset.