On a cta w/contrast of abdomen a liver: sub 6mm hepatic hypodensities are too small to characterize what does this mean? anything to worry about? what causes this? thank you?

Your medical history may be helpful for a better answer. There're many benign lesions in your liver which can present as small hypodense lesions such as cysts, hemangiomas, etc. However, these lesions can be serious if you have history of malignant disease such as colon, kidney or breast cancer. Without cancer history you doctor will order a follow up scan in 3 months for clarification. Good luck.