Term
| name originally used for MR |
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Definition
| Nuclear magnetic resonance |
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Term
| __ and __ discovered properties of MR |
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Definition
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Term
| Bloch and Purcell were awarded the Nobel Prize in __ |
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Definition
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Term
| Damadian showed that the relaxation of water in a ___ differed from that of water in a ____ |
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Definition
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Term
| represents the rates of signal decay and the return of protons to equilibrium |
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Definition
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Term
| ___ published the first crude cross sections of MRI in 1973 |
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Definition
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Term
| __ further showed how the signals could be mathematically analyzed which made it possible to develop a useful imaging technique |
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Definition
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Term
| Lauterbur and Mansfield were awarded the Nobel prize in __ |
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Definition
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Term
| spin on own axis, point in random directions, and will attempt to line up in a magnetic field |
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Definition
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Term
| strongest nuclear magnets that create the strongest MRI signal |
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Definition
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Term
| rotation that occurs after protons align with magnetic field |
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Definition
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Term
| protons in certain nuclei can be stimulated by radio waves of the correct frequency |
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Definition
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Term
| resonant frequency is introduced as ___ |
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Definition
| very fast bursts of radiowaves |
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Term
| after the RF pulse is applied, the protons that were spinning parallel to the ____ will now re-orient into the ___ of the RF |
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Definition
magnetic field,
perpendicular |
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Term
magnetization in the transverse (perpendicular) plane creates ____
and is processed by the computer as ____ to produce the image |
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Definition
an electrical current in the recieving antenna
an MRI signal |
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Term
| based on nuclear density, relaxation rates, and flow |
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Definition
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Term
| strong signals appear __ and weak signals appear ___ |
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Definition
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Term
| factors of signal strength |
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Definition
-proton density
-relaxation time
-flow |
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Term
| the number of processing nuclei in a given volume of tissue |
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Definition
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Term
the release of energy by the excited protons
occurs at different rates for different tissues |
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Definition
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Term
process of nuclei relaesing excess energy to the general environment
also called spin lattice relaxation |
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Definition
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Term
| release of energy by excited nuclei through interaction among themselves |
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Definition
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Term
| moving substances have a __ signal in MRI |
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Definition
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Term
| controls the computer, displays the image |
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Definition
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Term
| houses electronics, stores data temporarily |
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Definition
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Term
| contains major component of MRI |
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Definition
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Term
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Definition
-resistive magnets
-superconductive magnets
-permanent magnets |
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Term
simple, large electromagnet
requires cooling system |
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Definition
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Term
also electromagnets
cooled to low temp with liquid helium to reduce resistance, produces higher magnetic field |
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Definition
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Term
| constant field that does not require additional electricy or cooling |
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Definition
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Term
| magnetic field of ___ magnets does not extend as far away from the magnet (fringe field) |
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Definition
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Term
| ___ is a problem because it affects surrounding electronics |
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Definition
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Term
| FDA limits MRI system to a field strength of ___ |
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Definition
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Term
| most MRI have a strength of |
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Definition
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Term
| antennas required for transmitting the RF pulse and receiving MRI signal |
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Definition
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Term
| with a ___ time, more signal is available |
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Definition
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Term
classic sequence for T1 weighted images
can also provide T2 weighted images
useful when high signal from fat overwhelms small signal from underlying tissue of interest |
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Definition
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Term
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Definition
1. planes
2. slice thickness
3. imaging time
4. imaging sequence |
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Term
| sequence that accentuates T1 info and provides timing parameters to minimize signal intensity in tissue |
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Definition
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Term
| the only MRI contrast approved in the US, commonly used in CNS studies |
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Definition
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Term
| metal with paramagnetic effects ___ T1 relaxation time, producing ___ contrast images |
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Definition
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Term
used to improve image quality
if not used, the images of the heart may appear blurred |
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Definition
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Term
| MRI is ___ to CT for imaging posterior fosa and white matter diseases, such as ___ |
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Definition
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Term
| lungs, as well as blood in the great vessel have ___ MRI signal |
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Definition
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Term
| MRI is ___ sensitive to CT in detecting primary and metastatic tumors of the ___ |
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Definition
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Term
| parts of the musculoskeletal system such as ___, ___, and ___ are well visualized |
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Definition
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