Fig. 7. A thin slice of the area to be studied is divided evenly into multiple 3D voxels. The distinct radiofrequency signal emitted from these voxels determines the intensity of the corresponding pixels, which compose the total image of the slice. (Dortzbach RK, Kronish JW, Gentry LR: Magnetic resonance imaging of the orbit. Part I. Physical principles. Ophthal Plast Reconstr Surg 5:154, 1989)