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

Advanced imaging techniques have dramatically improved the diagnosis of brain tumors.

Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) is the standard crucial step for diagnosing a brain tumor. It provides pictures from various angles that can help doctors to construct a three-dimensional image of the tumor. It gives a clear picture of tumors near bones, smaller tumors, brain stem 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.

---

---

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 sensitive as an MRI in detecting small tumors, brain stem tumors, and low-grade tumors. It is useful in certain situations, however. Often, doctors will inject the patient with a 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 evaluate the effectiveness of treatments and watch for tumor recurrence.

Click the icon to see an image of a CT scan of the brain.

Positron Emission Tomography. Positron emission tomography (PET) provides a picture of the brain's activity rather than its structure by tracking a sugar that has been labeled with a radioactive tracer. It is sometimes able to distinguish between recurrent tumor cells and dead cells or scar tissue caused by radiation therapy. PET is not routinely used for diagnosis, but it may supplement MRIs to help determine tumor grade after a diagnosis. Data from PET may also help improve the accuracy of newer radiosurgery techniques. PET scans are often done along with a CT scan.