Final answer:
Glioblastoma multiforme usually appears on brain imaging as a heterogenous mass with both high and low-density areas on CT scans, a ring-enhancing lesion on MRI, and high glucose uptake on PET scans reflecting its high metabolic activity.
Step-by-step explanation:
Glioblastoma multiforme (GBM) typically appears on brain imaging as a heterogeneous mass with regions of both high and low density on CT scans, due to its necrotic and cystic components. On MRI scans, which are more sensitive than CT for soft tissue, GBM often presents with a characteristic ring-enhancing lesion, which means that the tumor has a necrotic core surrounded by an area of active tumor that accumulates contrast material. Additionally, GBM may cause local mass effect which can include midline shift or compression of adjacent brain structures. On PET scans, GBM may display as areas of high glucose uptake, reflecting the high metabolic demand of the cancerous tissue. Brain imaging techniques, such as CT, MRI, and PET, are crucial for the diagnosis and management of GBM.