Comd 4500 Unit 1 (weeks 4, 5) Exam Study Guide with Complete Solutions phrenology - Correct Answer the detailed study of the shape and size of the cranium as a supposed indication of character and mental abilities.related to phrenology - Correct Answer localization enlarged hippocampus of taxi driver example x ray imaging is - Correct Answer -broad xrays passed through tissue (to sensor or film) -energy is differentially absorbed (denser absorbs more, lighter in color) -2D view of 3D object (no dimensionality) xrays details - Correct Answer depend on tissue density differences to show structure, cannot show neural tissue, can show fractures, bone erosion, calsification, widely available, inexpensive, excellent spatial resolution cerebral angiography - Correct Answer x-ray imaging of the arterial blood vessels in the brain after injection of contrast material (catheter to femoral artery, aorta to carotid, front and lateral views, looks for abnormalities) AVM - Correct Answer arteriovenous malformation, abnormal proliferation of blood vessels in brain or spinal cord, relatively rare, 1% of people angiography advantages - Correct Answer -available in most hospitals -reveals speed of circulation -shows occlusions, aneurysms, arteriovenous malformations -allows inferences: tumors displacing vessels, creating large, irregular vessels angiography risks - Correct Answer -invasive -bleeding at artery puncture -stroke (clots, if emboli forms at catheter tip) -dye reaction 1 / 2
-exposure to xrays computed tomography (CT) - Correct Answer 2D slice through brain view, xray images, shows bone, neural tissue, CSF, can distinguish gray and white matter CT advantages - Correct Answer -quick 1-2 seconds -good spatial resolution -show bone abnormality and neural structures -contrast agent can show defects with blood/brain barrier -good for acute trauma CT disadvantages - Correct Answer -dense bone makes imaging difficult -exposure to radiation Positron emission tomography (PET) - Correct Answer a method of brain imaging that assesses metabolic activity by using a radioactive substance injected into the bloodstream *shows function rather than structure pathway of PET scan - Correct Answer isotope inhaled/injected -incoporated into glucose or neurotransmitter - isotope decay emits positron - positron collides w/ electron - collision destroys both, emits gamma rays 180degrees - sensors around head detect gamma rays PET localizing function - Correct Answer activity is picked on scanner represents glucose metabolism in the brain- during specific tasks different areas in brain show activity (given regions are more or less active) PET advantages - Correct Answer shows neural function, blood flow, metabolic activity. useful for diagnosis of cancer, alzheimers, seizure disorders, studying before/after treatments comparison PET disadvantages - Correct Answer limited spatial resolution, only available in large centers (medical/research centers), limited shelf life of isotopes magnetic resonance imaging (MRI) - Correct Answer brain-imaging method using radio waves and magnetic fields of the body to produce detailed images of the brain, virtual 2D slice
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