Diagnosis and conformation of Alzheimer's disease and other forms of dementia.
Localization of electrical and nonelectrical seizure foci.
Evaluation of location, size, and prognosis of cerebral ischemia and stroke patients.
Evaluation of AIDS dementia.
Changing brain perfusion during various types of interventions.
Evaluation of brain injury.
Evaluation of patients with psychiatric and mood disorders.
Detection and localization of recurrent brain tumor (Tc-99m and Tl-201agents).
Localization of Speech center
Diagnosis of brain death.
None. The imaging room should be quiet and dimly lit. An intravenous line is placed in advance so the patient does not experience pain from the needle puncture at the time of radiopharmaceutical injection.
Patient cooperation is needed. If sedation is required, please arrange with the nuclear medicine physician before the exam.
Tc-99m-hexamethylpropyleneamineoxime (Tc-99m-HMPAO), Dose: 20-30mCi.
or
Tc-99m-ECD, Dose: 20-30mCi.
1 - 2 hours. Pharmacologic stimulation studies can take considerably longer.
Tc-99m labeled HMPAO and ECD are lipid soluble and cross the blood brain barrier into nerve cells--particularly gray matter. CT and MRI studies provide high resolution anatomic images whereas, nuclear medicine imaging providesfunctional imaging. Evaluation of cerebral perfusion, cerebrovascular reserve, trauma and brain cell viability can be accomplished with nuclear medicine SPECT imaging.
Detection of recurrent brain tumor: Dual imaging with thallium-201 chloride and Tc-99m-HMPAO is useful in detecting and localizing recurrent brain tumor.
Acetazolamide (Diamox) may be used to increase the sensitivity of brain perfusion imaging for cerebrovascular ischemia:
1. Contraindications for Diamox Study:
a) allergy to sulfonamides (Acetazolamide is a non-bacteriostatic sulfonamide.).
b) active transient ischemic attacks (This is not an absolute contraindication.).
2. Side effects - occur in about 50% of patients & last for about 15 minutes:
a) numbness around mouth or fingers.
b) lightheadedness or blurred vision.
c) flushed feeling around face and neck.
3. Inject 1 gm of acetazolamide intravenously over 10-15 minutes.
4. Wait 15-20 minutes and then inject the radiopharmaceutical.
5. Wait 20 minutes and acquire images in the usual manner.
6. A baseline brain perfusion study without acetazolamide is performed one or more days later.
Other interventional or activation techniques may be used.
Quantification: Activity in the tomograms may be quantitated on a regional basis.
Superimposition of perfusion and anatomic images: Tc-99m-HMPAO images may be superimposed on corresponding magnetic resonance images with computer assistance.
Direct comparison of activated and baseline studies: Perform activation study with Tc-99m-HM-PAO and baseline study later. The activation and baseline images will be directly superimposed and examined.