CT scan of abdomen is usually done with oral contrast and i/v contrast and using both is essential to comment on lymphandenopathy. It is difficult to differentiate lymphnodes from unopacified bowel loops.
I have had multiple hernia repair all at once last Nov. Starting this March I began not feeling well only to find out after 5 repeated noncontrast use CT scans that I have a abdomen abscess. I was treated three time may-aug with 2 jp drain tubes and then a wound vac. After thinking I was o.k. through sept and oct. we have found through ct no contrast a "residual abscess". What causes this? Also why is it that some radiologist claim they cant "see" an abscess, yet its there (3.3cm x 1.6 cm) and the surgeon can look and see it?