CHAPTER 5 Nervous System^257
It is done to obtain pressure readings, obtain cerebrospinal fluid for analysis,
inject contrast medium or air for diagnostic tests, inject medications, or reduce
increased intracranial pressure.
The patient must lie flat for several hours after the procedure to reduce the risk
of spinal headache due to leakage of spinal fluid. Encourage oral fluid intake.
MRI with Gadolinium
This test is done to detect differences in tissue integrity, tumors, and disc disease.
Due to the use of a magnetic field to create images, an MRI is not for patients with
implanted hardware (pacemakers, etc.) or for pregnant women.
MRA (Magnetic Resonance Angiography)
This is done to detect arterial blockages, aneurysm, and arteriovenous mal-
formations.
PET (Positron Emission Tomography)
PET tells about the function of the brain involving glucose and oxygen metabo-
lism. The test is done to detect areas of altered metabolism such as dementia,
epilepsy, neoplasm, or degenerative disorders.
The patient is given a tagged isotope on deoxyglucose. There will be increased
glucose uptake by areas with increased metabolic activity.
Single Photon Emission Computed
Tomography (SPECT)
SPECT involves an intravenous injection of a radiopharmaceutical to enhance the
image. It is done to detect cerebral blood flow, stroke, dementia, amnesia, neo-
plasm, head trauma, seizures, persistent vegetative state, brain death, and psychi-
atric disorders. This test is not for pregnant women.