A dilated appendix on CT is a common finding that in many cases can be normal assuming that is the only finding. A dilated appendix is usually defined as measuring greater then 6 mm in thickness. However, normal patients without an appendix abnormality can have a more dilated appendix.
The most common abnormality of the appendix is appendicitis. This is an emergency and is usually treated with surgery. A burst or ruptured appendix can be life threatening so early treatment is required. A CT scan is usually used for diagnosis.
A dilated appendix in the absence of thickening, fluid, or inflammation can be normal. Unfortunately, an early appendicitis can also present as a dilated appendix on CT in the absence of other findings. In my experience, even early appendicitis usually shows a fluid filled appendix and thickening of the wall. However, in some cases it’s not possible to be sure. Especially if the patient has symptoms of appendicitis like right lower quadrant pain, nausea, lack of appetite, etc.
A dilated appendix in the setting of appropriate symptoms will raise some suspicion. In these cases, a surgeon will be consulted and the patient may be admitted to the hospital for observation or surgery depending on how suspicious the surgeon is. In some cases, a repeat CT scan will be done to see if the appearance of the appendix has worsened. This would be expected in the setting of appendicitis whereas a normal dilated appendix will remain the same.
A dilated appendix can therefore be normal or represent appendicitis. A dilated appendix can also represent other abnormalities such as a neoplasm. In these cases, the appendix is usually more dilated but sometimes indistinguishable from appendicitis. In either case, the appendix will come out and the pathology doctor will make sure it’s just appendicitis and there is no underlying tumor.
The diagnosis of appendicitis can be challenging in some cases and will require surgical consultation and possible repeat imaging. It’s also important to remember not to take the imaging finding of a dilated appendix on CT in isolation, but to consider it in the context of the patient’s presentation.