Exams and Tests (Part 2)
Instead of CT scan, the MRI scan is used for suspected brain tumors because MRI has a higher sensitivity for detecting the presence of, or changes within, a tumor. Most institutions, though still use the CT scan as the first diagnostic test.
Skull x-rays are not any more widely used to diagnose brain cancer.
You will be referred to a specialist in brain surgery if your scans indicate the presence of a brain tumor. You should also be referred to a specialist in brain tumors (neuro-oncologist).
Next step is to confirm that you have a cancer. A biopsy (a small sample of the tumor) is taken to identify the type of tumor. The most widely used technique for obtaining a biopsy is surgery, in which the skull is opened. The intention is to remove the whole tumor if possible. A biopsy is then taken from the tumor.
If the surgeon is not able to remove the whole tumor, the surgeon takes a small piece of the tumor.
There are some cases when it is possible to collect a biopsy without the need to open the skull. Using CT or MRI scans while the head is held still in a frame, the exact location of the tumor is determined stereotactically. A small hole is then made in the skull and a needle guided through the hole to the tumor. The needle collects the biopsy and is removed. This is called stereotaxis, or stereotactic biopsy.
The biopsy is examined under a microscope by a pathologist–a physician who specializes in diagnosing diseases by looking at tissues and cells.