Brain Death

Indications:
  • Confirmatory evaluation of Brain death and to assess blood flow to the brain.
  • Deep coma with absence of reflexes or spontaneous respiration
  • Other complications that may have caused the brain dysfunction must be ruled out and clinical findings of brain death must be present over a 24 hour period
Contraindications:
  • None

Questions asked in Patient History:

  • Does the patient have a history of head trauma or CNS injuries?
  • Has the patient received barbiturates? This can directly affect cerebral blood flow.
  • Patient trauma, infection and CNS ischemia is questioned as this can directly affect image interpretation.

Radiopharmaceutical information:
  • Radionuclide: Tc-99m
  • Radiopharmaceutical: Tc-99m GH, DTPA, HMPAO, or ECD
  • Adult dosing: 10-20 mCi
  • Pediatric dosing: 5-20 mCi DTPA, 10-20 mCi HMPAO,ECD
  • Method of administration: Bolus Injection
  • Method of Localization:
  • Physical Half-life: 6 hours

Patient Preparation:
No patient preparation is necessary

Side Effects:

Will the patient feel any different during or after the procedure?

Equipment Used:
Type of Camera or Probe
Collimator used: LEHR

Acquisition Setup:

Photopeak(s): 140keV

Window(s): 20%


Dynamic: View(s)- Anterior Flow
Matrix: 128x128
Time/Frame: 1 sec/frame
Number of Frames: 60 frames

Statics: View(s)- Anterior/ Posterior, Rt/Lt Laterals
Statics done post flow and 2hours post injection
Matrix: 128x128
Total Counts or Duration: 750k

Whole body: View(s)
Matrix:
Scan Speed:
Start/stop points:

SPECT:
180 or 90 degree configuration
Total Rotation: 180 or 360
Starting point:
Matrix:
Time/Azmuiths
Number of Azmuiths:

Processing:


Filter: Low Pass Butterworth
Cut-off:
Frequency:


Procedure:
Describe the procedure from verifying the requisition to completing the scan. Include any patient instructions pre- or post- injection/scan, delays between injection and imaging, and any side effects.
Supine with the head in a head holder secured with a velcro strap; the head is flexed so that the cerebellum is included in the field of view.
Imaging field: Entire brain including the cerebellum
1. Position the gamma camera for an ANT dynamic study of the head.
2. Inject radiopharmaceutical as a bouls and acquire 1 second/frame for at least 1 MINUTE
3. Approximately 15 minutes after injection acquire planar images in the ANT and right or left LAT projections.
4. Repeat static again in 2 hours post injection.



Normal Uptake and common varients:
Insert an image of a normal scan. Describe the normal uptake, and any normal varients visualized.

Abnormal Uptake and causes:
external image br002br117.gif
The patient was in an accident 3 days ago and has since been on a respirator with no response to pain. 20mCi Tc-99m DTPA was used and uptake is seen to the external carotid arteries and face, but no cerebral perfusion is seen. The lack of uptake to the brain suggests brain death but other studies must be done and evaluated extensively with one another to determine that the patient truly is clinically brain death.

external image FlowSoudry2.GIFFlow

external image PlanarSoudry2.GIFPlanar views
A different patient on Tc-99m HMPAO brain scintigraphy, the initial anterior flow study and subsequent planar views in the anterior and lateral projections demonstrate no appreciable intracerebral blood flow in either the internal carotid or posterior cerebral circulations.

Brain death is characterized by absent cerebral blood flow and global cerebral infarction. The brain scan can be used to confirm the absence of cerebral perfusion in suspected brain death. The study an be performed with intravenous bolus injection of Tc-99m HMPAO. Flow images are obtained in the anterior projection. Delayed images follow 5 to 10 minutes after the injection. Anterior and both lateral planar views are usually obtained. The diagnosis of brain death can be made only if intracranial activity is absent.

Artifacts:
Insert an image with an artifact, and explain what the artifact is.


References:
http://www.radiology.emory.edu/fileadmin/user/Forms__Processes___Procedures/NucMed/GenNucMed/Brain_Imaging.pdf

http://brighamrad.harvard.edu/Cases/bwh/hcache/20/full.html