1. by: Prof.Dr. Hosna Moustafa Cairo University, Egypt
Brain Imaging ( 1 )
by: Prof.Dr. Hosna Moustafa Cairo University, Egypt

2. Brain Imaging
Radionuclide brain imaging is differnet from anatomic imaging as C.T., M.R.I. in being functional imaging.
Radionuclides may be used to study:
Cerebral blood flow:
123-I iodoamphetamine
Tc99m- ECD
Tc99m- HMPAO

3. Principle radiopharmaceuticals used to study C.B.F.
Washout
Brain Uptake
Extraction
Peak activity (min.)
Redistribution
6.5 – 8 %
> 90% 20
I123-IMP
85 % stable
5 – 7 %
80 % 2
Tc99m-HMPAO
6 % per Hr.
70 %
Tc99m- ECD

4. Brain Imaging
Dual or single head SPECT gamma camera, multi-head is better (better resolution mm)
Low-energy high-resolution collimator
20% window at 140 KeV of Tc
Start imaging 30 minutes – 3 hours

5. Brain Imaging Ensure dim light with no noise
Patient is supine and head is fixed in head holder
Remind the patient NOT TO MOVE during the procedure
Imaging should be done for 360 degree, each for 30 sec., using 128 X 128 matrix.
Hamming or hanning filter is used in reconstruction to have images in transverse, sagittal and coronal cuts.

6. Normal brain perfusion study using Tc99m-HMPAO

7. Clinical Applications
Cerebro-Vascular stroke
Epilepsy
Dementia
Brain death
Traumatic lesions

8. Large left frontal and temporal lobe perfusion defect
Decreased perfusion to the right cerebellar hemisphere.
Large left middle cerebral artery stroke with crossed cerebellar diaschisis.

9. Base line study with large righ ttempro pariatal lobe hypoperfusion defect with Decreased perfusion to the left cerebellar hemisphere.
follow up study with partial improvement in cerebral perfusion

10. Focally increased perfusion involving the left fronto-temporal region (Luxury perfusion)

11. 2-Epilepsy
Epilepsy is a paroxysmal and transitory disturbance of the brain function.
Radionuclide brain SPECT can diagnose and localize site of focus in 70-90% as compared to 17-34% in C.T. and M.R.I.
If injected in ictal phase, a focal area of hyperperfusion is seen with 90% sensitivity.
If injected in inter-ictal phase, a focal area of hypoperfusion is seen with 60 – 70% sensitivity.

12. A B
Inter-ictal SPECT with hypoperfusion in the left temporal region
(B) Ictal SPECT with hyperperfusion in the left temporal region

13. 3- Dementia
Alziehemer’s disease is a common cause of dementia with scan pattern of bilateral hypoperfusion in temporoparietal regions, while basal ganglia is normal
Multi-infarcts dementia: multiple scattered areas of hypoperfusion in both cerebral cortices.

14. Early Alziehemer’s disease with bilateral hypo-perfusion in bilateral front-parietal regions, more evident in left side.

15. Advanced Alzeihemer’s disease with marked hypoperfusion all through the cortex with normal uptake in basal ganglia and minimal changes in C.T.

16. Perfusion defects involving lateral frontal, posterior parietal, and posterior temporal lobes on the left side.

17. 4- Brain Death
In patients with deep coma, it is important to be sure of brain death, especially if organ transplant is needed.
Scan pattern show no blood flow to the brain which is sure sign of death compared to EEG.

18. Initial SPECT study (before brain death) showed massive perfusion deficit in the areas supplied by the anterior and middle cerebral arteries.
A repeat SPECT study after 3 days showed NO cerebral perfusion, indicating brain death.

19. 5- Traumatic lesions Common with increased motor car accidents
Early functional damage can be detected with radionuclide imaging as areas of hypoperfusion.
The prognostic aspects depend on site and size of involved lesions, if multiple sites are involved or one half of the brain is more affected, this indicates poor prognosis.
Brain SPECT allow to evaluate degree of recovery in traumatic lesions.

20. CT shows small subarachnoid contusional hemorrhage in both frontal lobes
SPECT shows absence of tracer uptake in anteromedial aspect of both frontal lobes.
CT 1 month later shows hypodense haematoma in both frontal lobes
SPECT image show improvement in cerebral perfusion, in both frontal lobes.

21. Thank you