1. A method of creating and simultaneously displaying medical scan images, from each of: a first medical scan dataset, obtained by scanning a 3-dimensional (3-D) object with a first scanning modality, the first scanning modality being one of, or a combination of: Magnetic Resonance Imaging (MRI); Computed Tomography (CT); Positron Emission Tomography (PET); X-Ray; Ultrasound (US); and Single Photon Emission Tomography (SPECT); and a second medical scan dataset, obtained by scanning the 3-dimensional (3-D) object with a second scanning modality, the second scanning modality being one of, or a combination of: MRI; CT; PET; X-Ray; US; and SPECT; wherein the first and second medical scan datasets are 3-dimensional (3-D) datasets; and wherein at least the first medical scan dataset is a multi-volume dataset, comprising at least a first volume and a second volume of the 3-D object obtained by scanning the 3-D object in a single sitting of the first scanning modality; and the method comprising: deriving a first image from the first volume of the first medical scan dataset, the first image lying in a first plane, the first plane corresponding to an acquisition plane of the first volume of the first medical scan dataset, the acquisition plane being an imaging plane used at the time of acquisition of the first volume of the first medical scan dataset; obtaining a second image from the second medical scan dataset, the second image lying in the first plane; and displaying the first image and the second image simultaneously, wherein the method further comprising, upon a user selecting to switch to a view of an image from the second volume of the first medical scan dataset: deriving a third image from the second volume of the first medical scan dataset, the third image lying in a second plane, the second plane corresponding to an acquisition plane of the second volume of the first medical scan dataset; obtaining a fourth image from the second medical scan dataset, the fourth image lying in the second plane; and displaying the third image and the fourth image simultaneously.