Can a ct scan tell if a meningioma is cancerous?

Not definitively: Most meningiomas are not cancerous; sometimes the ct scan findings ((bone destruction, brain swelling, cystic change in tumor, etc.) can suggest a cancerous behavior. In some cases pet scans may be helpful. Ultimately, the definitive diagnosis can only be made by pathology review after surgery. Surgery is the usual treatment of choice for both ususal and cancerous meningioma anyway.

No: An MRI is needed for soft tossie.