The signs and symptoms of a brain tumor initially may be vague and come and go, making the diagnosis of a brain tumor difficult. Other diseases can cause similar signs and symptoms.

Diagnosing a brain tumor usually involves several steps. Your doctor may perform a neurologic exam, which among other things includes checking your vision, hearing, balance, coordination and reflexes. Depending on the results of that exam, your doctor may request one or more of these tests:

• Computerized tomography (CT) scan. A CT scan uses a sophisticated X-ray machine linked to a computer to produce detailed, two-dimensional images of your brain. You lie still on a movable table that's guided into what looks like an enormous doughnut where the images are taken. A special dye may be injected into your bloodstream after a few CT scans are taken. The dye helps make tumors more visible on X-rays. A CT scan generally takes less than 10 minutes.

• Magnetic resonance imaging (MRI) scan. This scan uses magnetic fields and radio waves to generate images of the brain. You lie inside a cylindrical machine for 15 minutes to an hour. MRI scans are particularly useful in diagnosing brain tumors because they outline soft tissues of the body as well as bone. Sometimes a special dye is injected into your bloodstream during the procedure. The dye sometimes makes tumors easier to distinguish from healthy tissue.

• Angiogram. This test involves injecting a special dye into your bloodstream. The dye, which flows through the blood vessels in the brain, can be seen on X-ray. This test helps show the location of blood vessels in and around a brain tumor.

• X-rays of the head and skull. An X-ray of the head may show alterations in skull bones that could indicate a tumor. It may show calcium deposits, which are sometimes associated with brain tumors. However, a routine X-ray is a far less sensitive test than brain scans and so is used less often.

• Other brain scans. Other tests, such as magnetic resonance spectroscopy (MRS), single-photon emission computerized tomography (SPECT) or positron emission tomography (PET) scanning, help doctors gauge brain activity by studying brain metabolism and chemistry and blood flow within the brain. These scans can be combined with MRIs to help doctors understand the effects of a tumor on brain activity and function, but doctors don't typically use them to make an initial diagnosis of brain tumor.

• Calcium (Calcium citrate)
• Calcium Gluconate)

If your doctor sees what appears to be a brain tumor on a brain scan, especially if there are multiple tumors, he or she may test for cancer elsewhere in your body before making a definitive diagnosis. Letting your doctor know of a prior history of cancer anywhere in your body, even many years earlier, is important.

The only test that can absolutely make a diagnosis of a brain tumor is a biopsy. This can be done as part of an operation to remove the tumor, or can be done in a separate procedure where only a small sample of tissue is obtained. A needle biopsy may be used for brain tumors in hard to reach areas within your brain. The surgeon drills a small hole, called a burr hole, into your skull. A narrow, thin needle is then inserted through the hole. Tissue is removed using the needle, which is frequently guided by CT scanning.

The tissue is then viewed under a microscope to determine if it is a tumor, and if so, what type of tumor. Additional tests on the tissue are often done to help determine the exact type of tumor, which may help in guiding treatment.

Depending on its size and location, a brain tumor can cause temporary or permanent brain damage. The brain is divided into different parts that are responsible for a variety of functions. For example, the front part of the brain (frontal lobe) is responsible for helping you think and managing motor skills. A brain tumor in the frontal lobe may press on or invade brain tissue in this area, resulting in learning or memory difficulties. It may also make talking or walking difficult. A brain tumor in the part of the brain called the occipital lobe — located in the back of the head — can result in vision problems because that area of the brain controls your ability to see and comprehend what you see.

Brain tumors may lead to an emergency complication known as hydrocephalus, which is the buildup of fluid in and around your brain. This occurs when a tumor blocks the flow of cerebrospinal fluid in and around your brain, causing fluid to build up within the confined spaces of your skull. This buildup can create pressure on delicate brain structures. The fluid must be drained to relieve pressure and reduce the risk of brain injury. Another emergency situation that can be caused by brain tumors is bleeding in the brain. This may require emergency medical treatment.

Your brain as a unit controls everything you do. An aggressive tumor that destroys too much brain tissue can be deadly.