Magnetic Resonance Imaging (MRI) Scan
Since its introduction into clinical practice, MRI has been
among the most important of all advances in the care of patients with
brain tumors.
This techniques method uses magnetic fields to generate images of the brain. The
patient lies inside a cylindrical machine for approximately an hour. MRI
scans are particularly useful in diagnosing brain tumors, because they
outline the normal brain structures in detail. It has become the current
standard of neuroimaging for brain tumor evaluation. Anatomic MRI with
gadolinium-based intravenous contrast agent, provides highly sensitive
tumor detection and characterization far superior to any other imaging
modality. MRI has been found to be more sensitive than CT in the detection
of asymptomatic progression of disease.Sometimes a special dye is
injected into the bloodstream during the procedure to help better
distinguish tumors from healthy tissue (MRI angiogram).
Read more...Computed
Tomography (CT) Scan
A CT scan uses a sophisticated X-ray machine linked to a computer to
produce detailed, two-dimensional images of the brain. A patient lies still on a
movable table that is guided into what looks like an enormous doughnut where the
images are taken. A special dye may be injected into the bloodstream after a few
CT scans to help better distinguish tumors (CT angiogram). A CT scan is painless
and generally takes less than 10 minutes.
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Angiogram
A special dye is injected into the arteries that go to the brain. The dye,
which flows through the blood vessels in the brain, can be seen on X-ray.
This test helps locate blood vessels in and around a brain tumor.
Other Brain Scans
Magnetic resonance spectroscopy (MRS)
Single-photon emission computed tomography (SPECT)
Positron emission tomography (PET)
These scans can be combined with MRIs to help physicians understand a
tumor's effects on brain activity and function. If a brain scan detects a
tumor, especially multiple tumors, physicians may test for cancer
elsewhere in the body.
X-rays of the Head and Skull
An X-ray of the head may show skull alterations indicating a tumor or
calcium deposits sometimes associated with brain tumors. However, an X-ray
is far less sensitive than brain scans and is used less often.
Biopsy
A biopsy is usually required to diagnose a brain tumor and confirm its
type. In a biopsy, a tiny piece of tumor is removed for examination under
a microscope. A biopsy can be performed separately or as part the surgery
to remove the tumor.
The tissue is examined by a neuropathologist to determine the kind of
tumor, which is critical to determining the proper treatment. It is
important that this analysis be performed by a pathologist who specializes
in brain tumors (a neuropathologist). Studies have shown that the
diagnosis may change substantially for at least one-third of patients when
an experienced neuropathologist does the review.
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