1. A medical X-ray examination apparatus ( 1 ) for performing K-edge imaging, comprising an imaging unit ( 21 ) which is configured to spectrally decompose an X-ray absorption spectrum to image the X-ray absorption spectrum as: a conventional X-ray absorption image ( 23 a ), including data elements representing the anatomical background of an object of interest, and a K-edge absorption image ( 23 b ), including data elements representing quantitative information of local densities of material showing K-edge absorption within the object of interest, characterized in that the imaging unit comprises a spatial resolution reducer for reducing the spatial resolution of the K-edge absorption image.