Answer

Answer 20-19. MRI scans are much better than CT scans at detecting metastasis (especially small ones), and CT scans are not very effective (particularly in the spine and posterior fossa of the head) unless there is destruction of bone. Plain x-rays are useful when the metastasis involves bone. At the present time, tissue diagnosis is critical to determine the type of tumor. In the future MR spectroscopy holds promise for noninvasive diagnosis.