First of all, let’s talk a little bit more about the use of X-rays as a diagnosis tool. There are currently two main medical imagery applications of X-rays: standard radiography in which we obtain a two-dimensional image of the inside of the body and CT scan where multiple X-rays images are combined together using a computer in order to create a three-dimensional image of a body part. Both techniques are routinely used nowadays in hospital for numerous purposes. However, X-ray based diagnosis methods are not usually considered as the method of choice to diagnose parasitic diseases, but it can be used successfully in some circumstances.
It is also more obvious to use these methods when suspecting an infection with helminths rather than with protozoan parasites, as the former one is usually visible with the naked eye and the latter one is microscopic. That means that protozoan parasites themselves cannot be seen using X-rays, as they are not visible with the naked eyes. Furthermore, even though some helminths might be detected using X-rays, other methods are usually required to formally identify which helminth is causing the infection in order to give the patient the appropriate treatment. Consequently, other diagnosis methods are actually more appropriate for the majority of parasitic infections.
The most obvious cases of parasitic infections detected using X-rays concern massive infestation with intestinal parasites, such as soil-transmitted helminths. In severe cases, patient might suffer from an obstruction of the bowel. However, helminths are not the only known cause of this condition. Consequently, X-rays are often used to help understand the cause of the bowel obstruction and worms causing this condition can then be visualised.
Some parasites might be harder to diagnose and X-rays could play a helful role in these circumstances. For instance, Echinococcus species are very difficult to diagnose and a combination of methods including CT scan is usually used. In that case, CT scan can help to find cystic structures within the organs confirming the suspected diagnosis. Granulomatous amoebic encephalitis, a severe fatal condition caused by either Acanthamoeba species or Balamuthia mandrillaris, are also very difficult to diagnose and are usually detected using brain scan at an advanced stage.
X-rays and CT scan can also be used as complementary detection methods to assess the severity of the infection. For example, X-ray based medical imagery can be used to detect the presence of abscesses caused by Entamoeba histolytica after the diagnosis of the infection using another method, such as specific antibody detection. As such, these medical imagery methods are used to evaluate the different organs’ damages caused by the parasite after the initial diagnosis and help in the choice of the best treatment as well as the establishment of a better prognosis.
Furthermore, it is interesting to mention that parasite’s cystic structures or larvae can also be detected accidentally inside the human body with an X-ray based medical imagery done for another purpose. In that case, other diagnosis methods would be used to confirm the diagnosis of a parasitic infection.
Source: Centers for Disease Control and Prevention