How good is a CT scan at finding brain tumours?
Contrast enhanced CT scans and MRI scans are both very good for finding primary or metastatic tumors in the brain, but No scan or test is perfect for finding early cancers – either primary of metastatic (spread to other areas). Here’s the problem – a billion cancer cells in one mass is only the size of a marble – – about 1cm in diameter. It is very easy for the best scans and the best radiologists to be unable to reliably find a mass much smaller than 1 cm. So, a clear scan means they see nothing large enough to be detected within the limits of technology. A person could have millions of cancer cells in the brain or elsewhere in the body that are simply too small to be seen with any test. They will show up only later when they grow. That is why doctors do periodic scans to monitor for developing masses. When they show up or become visible on scans, they have already been there for some time. People often have trouble understanding this concept. Cancers do not suddenly spread or suddenl
