An apparatus for visualizing medical image data comprises a data processing unit for obtaining first image data representing a first medical image, second image data representing a second medical image, and subtraction image data representing a subtraction image, wherein the subtraction image data is generated by subtracting one of the first medical image data and the second medical image data from the other of the first medical image data and the second medical image data, and the apparatus further comprises a feature identification unit for processing the first image data representing the first medical image to identify a feature, and a rendering unit for rendering a combined image comprising an overlay of the identified feature from the first medical image data and one of the subtraction image and the second medical image.