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Cards In This Set
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Compare/contrast MRI and CT scans
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CT- highly focused x-ray beam, absorbed by various tissues in the body. Beam is rotated in several steps to get different tissues absorbed differently. Bony tissue better detected. Contrast agents utilized: iodine, barium, barium sulfate, gastrogafinMRI- generated using magnetic fields, image depends on density of hydrogen nuclei. Differential magnetic fields are used. All tissues react differently to the magnetic field. Used for soft tissues,. Contrast commonly used: gadolinium (through the GI tract, IV, tumor-specific). MRI requires more time and pt cooperation- pt's who are claustrophobic might have more problems. The CT gives better detail of bony tissues, costs less $, less imagine time.
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Why might a child w/ a SNHL be referred for imagine?
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Used to detect structural abnormalities.
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What are some bony abnormalities relating to the auditory system?
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1) Michel deformity2) cochlear aplasia3) cochlear hyoplasia (under formed)4) Mondini malformation
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What are some membraneous deformities relating to the auditory system?
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1) Bing-Siebenmann deformity2) Scheibe Deformity
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Why might imaging be used during an evaluating for CI candidacy?
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Ensures that the cochlea has enough turns to take the electrodes- not ossified- as will happen w/ meningitis.
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What kind of imaging might be recommended for a pt with pulsatile tinnitus?
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MRA- magnetic resonance angiography- to rule out a vascular tumor of the temporal bone (glomus tumor)
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What are three additional uses of imaging for auditory disorders?
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1) pediatric conductive HL2) Evaluation of chronic disease3) Temporal bone trauma (fractures)
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What is a functional MRI (fMRI)?
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Used in studies of brain function. Stimulated w/ sound, used to study the function of the brain for research. Used it pts with epilepsy, tumors, etc.
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What is magnetoencephalography (MEG)?
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When a cap of electrodes is utilized to map cortical function- brain function is detectable.
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What is position emission tonography? (PET scan)
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Looks at structure and function, used to cancer pts to look for evidence of tumors.
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What does SPECT stand for? This is experimental imaging.
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Single photon emission computerized tomography
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What is cerumen and what is its purpose/ possible appearance?
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Cerumen is a mix of secretions (sloughed off epithelial cells, sebum), that may mix with hair and other matter. Its purpose is to lubricate and protect the ear canal. Cerumen exits the ear canal naturally by outward growth of the skin in the EC (33 mm / yr) It can be dry, wet, gooey, and flakey.
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What are some contraindictions for cerumen removal?
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TM perfs, HIV/AIDS, diabetes, anticoagulant Rx, PE tubes, mental retardation, ear malformations
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What is the incidence of cerumen impactions in the US?
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12 million- ranging between 6-18 million
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Who can perform cerumen removal?
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Physicians, nurse practioners, audiologists
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