A hypoattenuating lesion is an area on an organ that appears brighter than the rest of the organ on an X-ray or CT scan. The brighter area on the image of the organ indicates some sort of abnormality to the surface.
An X-ray and a CT scan are two different ways that doctors are able to take images of areas inside the human body. These types of imaging technologies help doctors diagnose issues with bones or organ tissue. The term hypoattenuating is used when describing something on the image that is brighter in color than everything else.
A hypoattenuating lesion refers specifically to lesions on the brain, kidneys and liver. The presence of a hypoattenuating lesion can either mean that there is a simple cyst or small sore on the surface of the organ, or it could indicate the presence of a tear or much more serious issue such as a malignant tumor. For instance, a liver cyst and a liver abscess are both benign issues that may not require surgery, or can be removed fairly easily if they are limiting the function of the liver. However, heptoblastoma and hepatocellular carcinoma are examples of hypoattenuating lesions that are cancerous and must be taken out immediately.