How can an radiologist tell the difference between a liver hemangioma and possible liver cancer?

MRI or CT scan: This is usually a pretty straight-forward distinction based on a ct or MRI scan. The important point is that the scan has to be ordered as a "hemangioma protocol" with IV contrast. Hemangiomas usually take up and release IV contrast in a predictable fashion in comparison with liver cancer. Rarely, if there is still a question, the mass can be biopsied without a serious risk for bleeding.

Varies: Usually the radiologist will use a combination of tests to tell. Sometimes an ultrasound with doppler, sometimes a ct scan, and sometimes an additional MRI scan may be indicated. There are specific findings on a radiology test that would help the radiologist tell the difference. Hemagiomas of the liver can be fairly common.

MRI or CT: Usually a radiologist can distinguish the two types of lesions via an MRI scan (and also a ct scan).