Can a ct scan without contrast dye detect brain tumours?

Should do it: If a brain tumor is causing significant symptoms, it should surely be large enough to be detected on a cat scan.

They may: But, you get a better chance (higher yield and more sensitivity) with a contrast enhanced test.

Sometimes: If tumor large enough to cause pressure on norma; strictires and displacement. Sometimes brain tumors have typical calcifications. If metastasis or tumor is same density as surrounding brain would need IV contrast to detect the tumor. Contrast shows vascularity of tumor or lack of perfusion compared to surrounding brain.