The right hemi-diaphragm is usually slightly higher than the left and if the right hemi-diaphragm is truly elevated it could be because of diaphragm paralysis, partial or complete, or because there is something beneath the diaphragm, pushing it up. Another possibility is that there is fluid between the diaphragm and the base of the right lung, giving the appearance of elevation or right lower lobe collapse with a compensatory rise of the diaphragm. A third possibility is that there is herniation of the diaphragm, such hernias sometimes containing a lobe of the liver.
Finally, a poor inspiratory effort when the x-ray is taken could accentuate the height of the diaphragms and the “prominence of the pulmonary vascularity and increase interstitial markings bilaterally.”
The first order of business should be to determine if the x-ray findings are or are not abnormal; possibly related to x-ray technique or inspiratory effort. This may require another x-ray interpretation by a board certified radiologist or that another x-ray be taken. Fluoroscopic examination can be helpful to assess diaphragmatic paralysis.