Can You See Appendicitis on X-ray?

No, but you can see some findings that may suggest the diagnosis.  Appendicitis presents with nausea, vomiting, pain and lab abnormalities.  The appendix arises off the cecum in the right lower abdomen.   The appendix is a blind ending tube.  Appendicitis happens when the opening becomes blocked from various causes.

Can we see the appendix on X-rays?

We can not see the appendix on X-rays in most cases.  It is rare to see a gas filled appendix on X-rays.  The appendix blends in with the surrounding tissues like bowel and fat in most cases.  The abdomen in the expected location of the appendix looks white, just like all the surrounding tissues.  Bowel which has air in it looks different.  This is because air is dark and everything around it is white.

X-rays of the abdomen are sometimes done when a patient has abdominal pain.  X-rays are able to give us some clues that appendicitis may be present.   An appendicolith can sometimes be seen in the right lower abdomen in the expected location of the appendix.

What are some findings seen with appendicitis on X-ray?

An appendicolith will appear as a small calcification or white spot.  An appendicolith is a small calcified deposit that can block the appendix and can cause appendicitis.  The cause of appendicoliths is not known for sure.   Appendicoliths seen in the right lower quadrant in the setting of suspected appendicitis raise the probability of appendicitis being present.

Appendicitis causes inflammatory changes in the right lower abdomen.  This can displace and inflame bowel loops in the right lower quadrant of the abdomen.  Sometimes we see thickening of bowel loops.  We can also see an ileus in the region of appendicitis.  This will look like dilated bowel loops.  The bowel loops become paralyzed and do not function properly.

Free air can sometimes happen when the appendix ruptures. There is normally no air outside the bowel in the abdomen.  If there is air outside the bowel, then it can be from the bowel or appendix rupturing.  This is best detected on upright studies of the abdomen.  We will see air under the diaphragms.

Why are X-rays done for appendicitis?

Negative X-rays do not mean there is no appendicitis.  Any clinical suspicion of appendicitis is often followed by a CT scan.  It is in those cases when appendicitis is not suspected that an X-ray may be ordered.  It is important for the radiologist to look for any signs of appendicitis in these cases.  Appendicitis is an emergency and often needs surgery.   Rupture of the appendix can lead to life threatening complications.

What is the best test for appendicitis?

In most cases, X-rays do not show appendicitis.  CT is by far the best test for this diagnosis.  In some cases, X-rays may be ordered for abdominal pain when appendicitis is not initially suspected.  In these cases, there may be some clues to the diagnosis.

An appendicolith can be seen which may raise suspicion.  Thickened or inflamed bowel in the right lower quadrant can be seen.   There can be an ileus from the appendicitis causing the bowel to be dilated.    It is much less common to actually see the dilated abnormal appendix.  This is because it is filled with fluid in many cases of appendicitis and blends in on X-ray with all the other tissues.