Low density shadows in the liver on CT can be associated with cysts, nodules, tumors, and other causes.
There are several conditions that can cause hypointense shadows in the liver, either due to physiological changes, disease, or examination errors.
If there is a fatty liver, it can cause hypodensity in the liver because of the low density of fat, although the changes due to fatty liver are mostly diffuse. The liver cysts, on the other hand, are mostly a physiological developmental abnormality that can appear as well-defined hypodense shadows in the liver. In addition, low density shadows found on CT can also be seen in benign nodules in the liver, as well as in malignant tumors of the liver. If the patient has motion during the examination, it can also cause artifacts and create examination errors.
After detection of hypointense changes, further tests such as liver function, hepatobiliary ultrasound, alpha-fetoprotein and hepatitis B and C virus testing, and if necessary, enhanced CT of the liver should be done. Through these tests, the cause of the hypointense shadow can be distinguished. If it is a cyst or benign nodule, the lesion will not intensify, so you can observe it first and do regular review. If there is abnormal liver function, elevated methemoglobin, and the lesion appears to be significantly enhanced, it suggests a malignant tumor of the liver, and surgery should be considered as soon as possible.