Computed tomography (CT)

CT (or computerised axial tomography/CAT) is a widely used imaging technology that assists in the diagnosis and treatment of many conditions. In the context of HIV, it can be helpful in the diagnosis of cancers and infections in the head, chest, gut, and lymph nodes.

It is particularly useful for visualising space-occupying lesions. Non-contrast-enhanced CT shows single or multiple hypodense lesions. The use of a contrast medium allows for visualisation of nodular or ring enhancement. CT is also used to diagnose and type community-acquired pneumonia and is a more sensitive test for this purpose than is chest X-ray.

The technology assesses the tissue density of narrow slices of the body. CT scanners can range from 4 to 64-splice capability. From these splices, a full CT image is generated that can show subtle changes in tissue type, lesions, and evidence of infections.

The person undergoing the scan lies on a table while the scanner passes over the body. The test is non-invasive and painless. Sometimes a contrast agent is used to light up areas of the body that are being imaged. In this case, an IV with contrast agent is inserted into the arm before the test is done.

Accurate diagnosis of opportunistic infections and malignancies will facilitate appropriate treatment.