Brain Imaging

1. Brain Imaging

2. Brain Imaging Common Indications • Detection and evaluation of cerebrovascular disease (stroke) • Diamox challenge – blood shunt • Evaluation of patients with suspected dementia (Alzheimer’s) • Pre-surgical localization of epileptic foci • PET • ECD • Evaluation of suspected brain trauma • altered Blood brain barrier • Differentiate between tumors and necrosis • Differentiate between tumors and infection • Brain Death – no arterial blood flow • DTPA blood flow • HMPAO, ECD – brain specific tracers • CSF Dynamics • Cisternogram • Shunts • Leakage Frank P. Dawry Physx.home.comcast.net

3. Anatomy Cerebrum - Two hemispheres connected by nerve bundles (Corpus Callosum ) • Frontal lobe • located directly behind the forehead • helps control voluntary movement • aids higher intellectual functions • as solving a math problem • planning an event. • Temporal lobe • Associated with speech, sound and complex visual perceptions. • Occipital lobe • deals with vision. • Parietal lobe • plays a role in sensory processes, attention and language. Frank P. Dawry Physx.home.comcast.net

4. Anatomy Midbrain • relays sensory information from sense organs to other brain areas • coordinates some reflex activity • size of the eye’s pupil. Hindbrain • relays information from the spinal cord to other parts of the brain • helps control movement coordination, involuntary functions and equilibrium. • Cerebellum • helps control movement • aids cognitive processes that require precise timing, such as playing a musical instrument. Spinal cord • is protected by a fluid-filled bony canal and extends along the back • in an adult it is roughly 18 inches long and contains 31 pairs of nerves. • serves as a pathway for nerve signals to travel to and from the brain • as a center for coordinating many reflex actions independently of the brain Frank P. Dawry Physx.home.comcast.net

5. Ventricular system CSF • Formed in the choroid plexus in each ventricle • Provides a fluid cushion upon which the brain “floats” • Removes waste • Provides nutrients Frank P. Dawry Physx.home.comcast.net

6. Vascular system • Arterial blood supplied by • Internal Carotid Arteries • Vertebral Arteries Frank P. Dawry Physx.home.comcast.net

7. Vascular system • Anterior Cerebral Arteries supply the • Frontal lobes • Parietal lobes • Posterior Cerebral Arteries supply the • Temporal lobes • Occipital lobes Frank P. Dawry Physx.home.comcast.net

8. Blood-Brain Barrier • The tight seal of cells that lines the blood vessels in the brain • Allows • Lipophillic diffusion • Selective active transport • Excludes • Large molecules • Toxins Unless disrupted Frank P. Dawry Physx.home.comcast.net

9. SPECTSingle Photon Emission Computerized Tomography Frank P. Dawry Physx.home.comcast.net

10. Tomographic planes Frank P. Dawry Physx.home.comcast.net

11. Image Orientation Frank P. Dawry Physx.home.comcast.net

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14. Radiopharmaceuticals • Cerebrovascular Disease, Epilepsy - Perfusion studies (vascular imaging) • Crosses the intact Blood-Brain barrier (BBB) - Lipid-soluble • Tc99m-HMPAO (Exametazime) – CERETEC (stabilized) • 15 - 30 millicuries (mCi) • Tc99m-Bicisate (Ethyl cystine dimer [ECD]) – NEUROLITE • 10 - 30 millicuries (mCi) • FDG • Tumor • altered BBB • Tl-201 Thallium - does not normally cross the BBB • 3-5 millicuries (mCi) • Tc99m-Sestamibi - does not normally cross the BBB • 10-20 millicuries (mCi) • FDG – increased glucose metabolism • CSF - cisternogram • In-111 DTPA – sterile (pyrogen free) • 0.4 – 0.75 millicuries (mCi) • Brain Death • no arterial blood flow • DTPA blood flow • HMPAO, ECD – brain specific tracers Frank P. Dawry Physx.home.comcast.net

15. Neuroendocrine tumor imaging • Neurotransmitters • chemical messengers released at nerve ending terminals • bind to receptors on the surface of the target neuron. • Octreoscan • Indium-111 Frank P. Dawry Physx.home.comcast.net

16. Vascular imaging Pre-Arrival Patients should be instructed to avoid caffeine, alcohol or other drugs known to affect cerebral blood flow (CBF). Pre-Injection Evaluate the patient for his/her ability to cooperate. Achieve a consistent environment at the time of injection and uptake: i. Place the patient in a quiet, dimly-lit room. ii. Instruct the patient to keep his/her eyes and ears open. iii. Ensure that the patient is seated or reclining comfortably. iv. Place intravenous access at least 10 min prior to injection to permit accommodation. v . Instruct the patient not to speak or read. vi. Have no interaction with the patient prior to, during or up to 5 min post-injection. Perform SPECT imaging 30 minutes post injection 128x128 matrix 3 degrees/step 20 seconds/stop Patient Procedure Frank P. Dawry Physx.home.comcast.net

17. Tumor - altered BBB No special preparation 3-4 millicuries (mCi) Perform SPECT imaging 10 minutes and 3 hours post injection – analyze ROIs 128x128 matrix 3 degrees/step 20 seconds/stop CSF - cisternogram Sterile injection! Performed by a RAM licensed physician, or under his/her supervision image at 6, 24 & 48 hours post injection Medium energy collimation 173 & 247 photopeak window 100,000 counts/image or 10 minutes/view 128x128 matrix Brain Death Tourniquet around the patient’s scalp, just above the eyebrows and ears – so long as there is no history of brain trauma Obtain flow in anterior or posterior projection 128x128 matrix 2 seconds/frame for 90 seconds Obtain Anterior, Left and Right Lateral, and if possible, Posterior static (planar) images at 5 minutes post flow 256x256 matrix 500,000 counts/image Patient Procedure Frank P. Dawry Physx.home.comcast.net