How sensitive and specific would ct without contrast be for chronic appendicitis?

Not ideal: For visualizing structures in the abdomen, contrast really helps -both IV and oral. Sometimes a 'dry' scan (no contrast) is done when considerations about kidney function are raised, since the IV contrast can damage the kidneys. The appendix can be hard to visualize as it is - so if possible, a high quality test is definitely better. Depending on the extent of disease too, might affect the results