Which is more accurate ct scan or mri in determining the exact size of meningioma?

Both: Ct with contrast is used as is MRI with gadolinium for diagnosing and evaluating the size of the meningioma. A radiologist would generally make a recommendation for the proper diagnosis.

Both accurate: Both are accurate. Very effective imaging techniques.

MRI is better: I know dr. Pilcher and he is a great neurorsurgeon but because MRI can image in all planes and has much better delineation in the posterior fossa and dura - it is much more accurate than ct. Ct also involves a high radiation dose and also nephrotoxic contrast. 1 in 5 patients gets transient contrast induced nephropathy. Use mri.