Brain Tumors: Primary - Diagnosis

Diagnosis

A neurological exam is usually the first test given when a patient complains of symptoms that suggest a brain tumor. The exam includes checking eye movements, hearing, sensation, muscle movement, sense of smell, and balance and coordination. The doctor will also test mental state and memory.

Imaging Techniques

X-rays of the skull were once standard diagnostic tools but are now performed only when more advanced procedures are not available. Advanced imaging techniques have dramatically improved the diagnosis of brain tumors in recent years.

Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) is the gold standard for diagnosing a brain tumor. It does not use radiation and provides pictures from various angles that can enable doctors to construct a three-dimensional image of the tumor. It gives a clear picture of tumors near bones, smaller tumors, brainstem tumors, and low-grade tumors. MRI is also useful during surgery to show tumor bulk, for accurately mapping the brain and for detecting response to therapy.

A variant called magnetic resonance spectroscopy (MRS) is capable of providing information on the activity of the brain using magnetic resonance imaging. MRS is proving to be accurate for distinguishing dead (necrotic) tissue caused by previous radiation treatments from recurring tumor cells in the brain, a difficult diagnostic issue.

Computed Tomography. Computed tomography (CT) uses a sophisticated x-ray machine and a computer to create a detailed picture of the body's tissues and structures. It is not as accurate as an MRI and does not detect about half of low-grade gliomas. It is useful in certain situations, however. Often, doctors will inject the patient with an iodine dye, called contrast material, to make it easier to see abnormal tissues. A CT scan helps locate the tumor and can sometimes help determine its type. It can also help detect swelling, bleeding, and associated conditions. In addition, computed tomography is used to check the effectiveness of treatments and watch for tumor recurrence.