PRELIM Flashcards
(208 cards)
1
Q
the medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body.
A
MAGNETIC RESONANCE IMAGING
2
Q
It is a medical technique that uses a magnetic field and computer-generated radio waves to create detailed images of the organs and tissues in your body.
A
MAGNETIC RESONANCE IMAGING
3
Q
what year did Damadian discovered that MRI could be used for medical diagnosis. Cancer tumours emitted different signals compared to healthy tissue.
A
1971
4
Q
in what year did Damadian built the first whole-body MRI in which he called the ‘Indomitable’ (impossible). Over 60 million MRI examinations are now carried out annually.
A
1977
5
Q
Damadian built the first whole-body MRI in 1977, which he called the ‘Indomitable’, what does mean?
A
impossible
5
Q
Damadian built the first whole-body MRI in 1977, which he called the ‘__________’ (impossible). Over 60 million MRI examinations are now carried out annually. called what?
A
Indomitable
5
Q
how many millions? MRI examinations are now carried out annually.
A
over 60 millions
6
Q
who was able to image a student’s finger in 15-23 minutes in 1974.
A
Mansfield
7
Q
when was Mansfield able to image a student’s finger in 15-23 minutes in what year
A
in 1974.
8
Q
what Mansfield was able to image in 15-23 minutes in 1974.
A
a student’s finger
9
Q
how many minutes Mansfield was able to image a student’s finger in 1974.
A
in 15-23 minutes
9
Q
who was the person/s race to create the first whole-body MRI scanner began shortly thereafter
A
Damadian and Mansfield
9
Q
how many years later when Damadian created the first whole-body human scanner in May of 1977.
A
Three years later
10
Q
Three years later, Damadian created what? in May of 1977.
A
the first whole-body human scanner
10
Q
Three years later, Damadian created the first whole-body human scanner in what month and year
A
May of 1977.
10
Q
the inventor of the first magnetic resonance scanning machine celebrates his 85th birthday on March 16. Damadian, a physician, performed the first full-body scan of a human being in 1977.
A
Dr. Raymond Damadian
10
Q
Dr. Raymond Damadian, the inventor of the first magnetic resonance scanning machine celebrates his 85th birthday on what month and date?
A
March 16
11
Q
Dr. Raymond Damadian, the inventor of the first magnetic resonance scanning machine celebrates on how old he is his on March 16?
A
85th birthday
11
Q
a physician, performed the first full-body scan of a human being in 1977.
A
Dr. Raymond Damadian
11
Q
Damadian, a physician, performed the first full-body scan of a human being in what year?
A
1977.
11
Q
Damadian, a physician, performed what? in 1977.
A
the first full-body scan of a human being
11
Q
MR imaging was invented by who developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients in September 1971;
A
Paul C. Lauterbur
11
Q
what did Paul C. Lauterbur invented who developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients in September 1971
A
MR imaging
11
Q
MR imaging was invented by Paul C. Lauterbur who developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients in what month and year?
A
September 1971
12
MR imaging was invented by Paul C. Lauterbur what he is dveloped?
developed a mechanism to encode spatial information into an NMR signal using magnetic field gradients
12
MR imaging was invented by Paul C. Lauterbur who developed a mechanism to encode spatial information into an?
an NMR signal using magnetic field gradients
12
he published the theory behind it in March 1973.
Paul C. Lauterbur
12
Paul C. Lauterbur published the theory behind it in what month and year?
March 1973.
12
what is a material or object that produces a magnetic field
A magnet
13
is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel cobalt, etc. and attracts or repels other magnets.
magnetic field
13
A magnet is a material or object that produces what?
magnetic field
13
is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.
A magnetic field
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surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time.
Magnetic fields
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is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger-Marsden gold foil experiment.
The atomic nucleus
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The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in what year by Ernest Rutherford based on the 1909 Geiger-Marsden gold foil experiment.
1911
14
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by who?
Ernest Rutherford
14
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on what year?
1909
14
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 what experiment?
Geiger-Marsden gold foil experiment.
14
is a quantum-mechanical property, akin to the angular momentum of a classical sphere rotating on is axis, except it comes in discrete units of integer or half-integer multiples of . The proton, like the electron and neutron, has a spin of ℏ/2
PROTON SPIN
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is a quantum-mechanical property, akin to the angular momentum of a classical sphere rotating on is axis, except it comes in discrete units of integer or half-integer multiples of . The proton, like the electron and neutron, has a spin of ℏ/2
Spin
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also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current.
Radiofrequency ablation
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also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternating current.
Radiofrequency ablation
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Radiofrequency ablation, also called what?
fulguration
17
TYPES OF MAGNET USED IN MRI
1. PERMANENT MAGNET
2. RESISTIVE MAGNET
3. SUPERCONDUCTIVE MAGNET
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employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with the field. When a radiofrequency current is then pulsed through the patient, the protons are simulated, and spin out of equilibrium, straining against the pull of the magnetic field.
MRIs
18
MRI contains with
Magnet
RF coils
Gradient coils
scanner
18
These are materials where the magnetic field is generated by the internal structure of the material itself. But in certain materials, called ferromagnets, all the spins and the orbits of the electrons will line up, causing the materials to become magnetic. This would be your normal iron, cobalt, nickel.
permanent magnet
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The uniform magnetic field is found inside the coil, especially in the center. These magnets are relatively inexpensive to make but require a large contact flow of current while magneitzed and imaging. The coil has an electrical resistance that requires cooling of the magnet.
resistive magnet
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is an electromagnet made from coils of superconducting wires in is superconducting state the wire has no electrical resistance and therefore can conduct much larger electric currents than ordinary wire, creating intense magnetic field.
A Superconducting magnet
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uses in MRI, because wrapped up in coil, generating magnets all around
A Superconductive magnet
19
Most MRI systems use what type of magnet
superconducting magnets
19
The primary advantage is that a superconducting magnet is capable of what? than the other two types (resistive and permanent) considered below.
producing much stronger and stable magnetic field
20
The primary advantage is that a superconducting magnet is capable of producing much stronger and stable magnetic field than the other two types of magnet
resistive and permanent
20
the one who receive a primary radiation
patient
20
what receive primary radiaion radtech
scattered
20
what to patient to film, comes from primary radiation
SECONDARY RADIATION
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is the the construct which determines teh ate at which excited protons reach equilibrium or go out of phase with each other
T2 (transverse relaxation time)
21
it is a measure of the time taken for spinning protons to lose phase coherence among the nuclei spinning perpendicular to the main field.
T2 (transverse relaxation time)
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is the concentration of signal bearing spins. The instrumental variables are the: Repetition Time TR, and Echo Time TE.
spin density
21
two types of spin density: The instrumental variables are the:
- Repetition Time TR, and
- Echo Time TE.
21
what type of spin density that - maintain detailed and well persecute anatomical.
*LONG TR, SHORT TE
21
is the ratio of the magnetic momentum in a particle to its angular momentum.
The gyromagnetic ratio
22
The gyromagnetic ratio, often denoted by the symbol of?
gamma
22
The gyromagnetic ratio the SI unit is what
the radian per second per tesla (rads-1T-1)
22
What is The gyromagnetic ratio of the proton
2.675 221 900 (18) 108s-1T-1
23
a vector quantity that is a measure of the torque exerted on a magnetic system (such as bar magnet or dipole) when placed in a magnetic field is the product of the distance between its poles and the strength of either pole.
MAGNETIC MOMENTUM
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also known as spin, is the velocity of rotation of something around an axis. Gyroscopes are simple decrease that exploit the conservation of angular momentum to stabilize, guide or measure rotational movement in many type of systems
ANGULAR MOMENTUM
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are simple decrease that exploit the conservation of angular momentum to stabilize, guide or measure rotational movement in many type of systems
Gyroscopes are simple decrease that exploit the conservation of angular momentum to stabilize, guide or measure rotational movement in many type of systems
24
it plays in Nuclear Magnetic Resonance (NMR) and MRI
The gyromagnetic ratio of a nucleus
24
is particulate important because of the role it plays in Nuclear Magnetic Resonance (NMR) and MRI
The gyromagnetic ratio of a nucleus
24
The gyromagnetic ratio of a nucleus is particulate important because of the role it plays in what?
Nuclear Magnetic Resonance (NMR) and MRI
25
is a special case of forced vibrations. When the frequency of an externally applied periodic force on a body is equal to its natural frequency, the body rapidly begins to vibrate with an increased amplitude
RESONANCE
25
are critical to nuclear excitation and signal reception in MRI. The interactions between these fields and human tissues in anatomical geometrics result in a variety of effects regarding image of humans integrity and safety.
RADIOFREQUENCY FIELD
25
are critical to nuclear excitation and signal reception in MRI. The interactions between these fields and human tissues in anatomical geometrics result in a variety of effects regarding image of humans integrity and safety.
RF magnetic fields
26
MRI uses magnetic fields and radiowaves to measure how much water is in different tissues of the body, maps the location of the water and then uses. This information to generate a detailed image. The images are so detailed because over bodies are made up of around 65% water, so to have a lots of resource to measure.
IMPORTANT OF RF IN AN MRI
26
IMPORTANT OF RF IN AN MRI?
MRI uses magnetic fields and radiowaves to measure what? This information to generate a detailed image.
how much water is in different tissues of the body, maps the location of the water and then uses.
26
MRI uses magnetic fields and radiowaves to measure how much water is in different tissues of the body, maps the location of the water and then uses. This information to generate a detailed image. The images are so detailed because over bodies are made up of around how many percent of water? so to have a lots of resource to measure.
65% water
26
magnetic fields used in MRI are typicals in the range 1 to 4. The corresponding Larmour frequencies are about 43 to 170 MHz. These frequencies are in the RF range, which are much lower than x-rays capitalized and do not disrupt tissue.
LARMOUR FREQUENCY
26
LARMOUR FREQUENCY, magnetic fields used in MRI are typicals inwhat range?
range 1 to 4
26
The corresponding Larmour frequencies are about how many MHz? These frequencies are in the RF range, which are much lower than x-rays capitalized and do not disrupt tissue.
43 to 170 MHz
26
These frequencies are in the RF range, which are much lower than x-rays capitalized and do not disrupt tissue.
LARMOUR FREQUENCY
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vector in MRI is the summation of the magnetic moment of the individual hydrogen nuclei. In the absence of an external magnetic field, the individual magnetic moment are randomly oriented and share they are in opposition
net magnetization
27
in what year,Felix Bloch and Edward Purcell first discovered the properties of magnetic resonance.
1940s
27
in what year, MRI spectroscopy technique they used for analysis of complex molecular structures and dynamic chemical processes.
1940s
27
in 1940s, who are the persons first discovered the properties of magnetic resonance.
Felix Bloch and Edward Purcell
27
in 1940s, what technique they used for analysis of complex molecular structures and dynamic chemical processes.
MRI spectroscopy technique
27
in what year, Bloch and Purcell shared a Nobel Prize in Physics
1952
28
in 1952, who are shared a Nobel Prize in Physics
Felix Bloch and Edward Purcell
28
in what year, Raymond Damadian showed that the relaxation time of water in a tumor differed from the relaxation time of water in normal tissue
1971
28
in 1971, who showed that the relaxation time of water in a tumor differed from the relaxation time of water in normal tissue
Raymond Damadian
28
in what year, Investigated excised rat tissue He reported that there were significant differences between normal rat tissues and tumors
1971
28
in 197, Investigated excised what animal? tissue He reported that there were significant differences between normal tissues and tumors
a rat
28
in what year, Paul Lauterbur published the First cross-sectional image of objects (two water-filled capillary tubes) obtained with MRI technique.
1973
28
in 1973, who published the First cross-sectional image of objects (two water-filled capillary tubes) obtained with MRI technique.
Paul Lauterbur
29
in 1973, what objects did Paul Lauterbur published obtained with MRI technique.
the First cross-sectional image of objects (two water-filled capillary tubes)
29
in what year, Damadian obtained the first animal images
1975
29
in 1975, who obtained the first animal images
Damadian
29
in 1975 Damadian obtained what the first images
animal images
29
when was MRI was progressing rapidly
1978s
29
in what year, The first human head scans were obtained
1978
29
in what year, Followed by the first human body scans
1978
30
Original name of the first MRI machine
INDOMITABLE
30
A computer-based cross-sectional imaging modality The use of magnetic field and radio waves to obtain a mathematically reconstructed image.
MAGNETIC RESONANCE IMAGING
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MAGNETIC RESONANCE IMAGING
Originally called what?
Nuclear Magnetic Resonance
31
Device for transmitting or receiving radio wave.
ANTENNA
31
ADVANTAGES OF MRI
Best low contrast resolution
Rationale:
The X-ray attenuation coefficient in soft tissue differ by <1% (in the same tissue)
Spin density & T1 differ by 20-30% (in the same tissue)
T2 differ by 40% (in the same tissue)
No ionizing radiation
Direct multi-planar imaging
No bone or air artifact
Direct flow measurements
Totally noninvasive
Contrast media is not required
32
what is Spurious finding in or distortion of an image.
ARTIFACTS
32
what is Reduction in energy or amount of a beam of radiation when it passes through tissue or other substances
ATTENUATION
33
what is Single or multiple loops of wire designed to produce a magnetic field from the current flowing through the wire
COIL
33
what is Relating to extremely low temperature.
CRYOGENIC
33
what is The fear of having no escape and being in closed or small spaces or rooms.
CLAUSTROPHOBIA
34
what is Spontaneous random motion of molecules in a medium.
DIFFUSION
34
what is Fat tissue in the image is made to be of a lower, darker signal intensity.
FAT SUPPRESSED IMAGES
34
what is Signal emitted by tissue after RF excitation.
FREE INDUCTION DECAY
34
what is Technique used in reducing motion artifacts.
GATING
35
what is Fast pulse sequence.
Often used with 3D imaging to generate T2 weighted images
GRADIENT ECHO
36
what is A change in the intensity of a magnetic field in space.
Unit: mT/cm
GRADIENT MAGNETIC FIELD
36
what is A constant, specific ratio for each nucleus Half-life in MRI
Unit: MHz/T
Hydrogen: 43 MHz/T
Most abundant element in the body (60%)
GYROMAGNETIC RATIO
37
what is Standard pulse sequence available in most.
MRI imagers.
Used for T1-weighted images.
INVERSE RECOVERY
37
what is The frequency at which a nucleus precesses in the magnetic field. Unit: MHz
LARMOR FREQUENCY
37
what is A force is created when the magnetic dipole is in a magnetic field.
The inherent magnetism.
Unit: T
MAGNETIC MOMENT
37
what is The large-scale macroscopic magnetic moment resulting from many nuclear magnetic moments.
MAGNETIZATION
37
what is Magnetic moment of individual hydrogen nuclei aligned in the external magnetic field.
NET MAGNETIZATION
38
what is Flow of blood through vessels of an organ or unatomic structure.
PERFUSION
39
what is The wobble of the rotational exia of a spinning body ubout a stationary axis.
Describes s CODE
Rate of precision increases as MF strength increases
RADIOFREQUENCY (RF)
39
what is Information obtained by radio reception of the MRT signal is stored by a computer.
RAW DATA
39
what is Returning to equilibrium
The time required for return
RELAXATION
40
what is Transfer of vibrating energy from system to another.
RESONANCE
40
what is The power absorbed during RF irradiation
Unit: W/kg
SPECIFIC ABSORPTION RATE (SAR)
40
what is Concentration of hydrogen nuclei in tissue
Principal determinants of
MRI signal
SPIN DENSITY (SD)
40
what is Spin-lattice relaxation time
Longitudinal relaxation time
Decrease in signal: 63% of maximum value
T1 RELAXATION TIME
40
what is Spin-spin relaxation time
Transverse relaxation time
Decrease in signal: 37% of maximum value.
T2 RELAXATION TIME
41
what is SI unit of magnetic field strength
1T 10,000 G
TESLA
41
what is MRI depends on the properties of the nucleus
Hydrogen nuclei: element used in most MRI
Rationale: Strongest nuclear magnets
Create the strongest MRI signal
A most common element in the body
SIGNAL PRODUCTION
41
what is Classic imaging sequences
Most widely used pulse sequence
Used with timing parameters to yield T1 weighted images
Also provide pro ton-density weighted images
Time-consuming
Slow patient “throughput” or productivity
SPIN ECHO SEQUENCE
42
in SPIN ECHO SEQUENCE Slow patient what or also know as productivity
“throughput”
42
what is A sequence that accentuates T1 information
Time-consuming
Slow patient throughput or productivity saturate fat
INVERSE RECOVERY
42
what is Used to minimize the high signal intensity from fat tissue overwhelming small signal intensity in the tissue of interest
FAT SUPPRESSED IMAGES
42
what is Oldest imaging sequence
The most common type of faster imaging sequence
GRADIENT ECHO
42
what is Fast gradient imaging technique
Good wherever there is turbulent flow
FAST GRADIENT ECHO
43
what is Known as rapid acquisition recalled echo
FAST SPIN-ECHO
43
what is Suppresses signal from cerebrospinal fluid (CSF)
Most applicable in the brain
For seizures disorders
For spinal cord injuries
FLUID ATTENUATED INVERSION RECOVER (FLAIR)
43
what is Suppresses signal from fat
SHORT TAU INVERSION RECOVERY
43
what is Short T1
Produces high MRI signal in T1 weighted images
FAST SPIN-LATTICE RELAXATION RATE
43
what is Long T2
Produces high MRI signal in T2 weighted images
SLOW SPIN-SPIN RELAXATION RATE
43
what is Brightness the primary visual factor, determined by RF signal strength.
Image Quality
44
in Image Quality, what is Brighter than its surroundings.
Hyperintense
44
in Image Quality, what is Darker than its surroundings.
Hypointense
44
in Image Quality, what is same brightness as its Surroundings
.
Isointense
44
three types of Image Quality
- Hyperintense
- Hypointense
- Isointense
45
Factors affecting Image Quality:
1. Field Strength
2. Section Thickness
3. Imaging Parameters
4. Motion (temporal resolution]
5. Spatial Resolution
6. Signal-to-Noise Ratio (S/N)
46
in Factors affecting Image Quality, what is Higher field strength produces a higher RF signal, thus Brighter images.
Increase FS, Increase RF intensity. Increase Brightness
Field Strength
46
in Factors affecting Image Quality, what is Determined by the size and depth of the tissue voxel.
Determines the smallest tissue differences that can be an image, therefore image resolution.
Increase ST decreases resolution, Decrease image quality
Section Thickness
46
in Factors affecting Image Quality, what is Manipulation of extrinsic parameters controls the acquisition of various T1, T2, and PD measurements, thus affecting image quality.
Imaging Parameters
46
in Factors affecting Image Quality, what is Long scan times disable the patient to control movements.
Gating techniques
Synchronization on ECG waves Breathing instruction and good communication.
Motion (temporal resolution]
47
in Factors affecting Image Quality, what is Ability to distinguish one structure from another.
determined by the homogeneity of Bo, steepness of gradient (INV) fields, and scan time (DRT).
Spatial Resolution of current MRI is 0.1mm
Increase SP, Increase Image Qualitv
Spatial Resolution
47
in Factors affecting Image Quality, what is extraneous visual information,
determined by Voxel size (INV), Proton Density (INV), pulse sequence, and field strength (DRT). Thermal Noise noise produced by increase. random molecular motion with increase in body temperature
Increase S/N, Increase
Signal-to-Noise Ratio (S/N)
47
what is Gadolinium-containing compounds
CONTRAST MEDIA
47
what is a type of contrast media that a metal with a paramagnetic effect
Gadolinium
47
effects of gadolinimnum
- Lower toxicity
- Few side effects
47
whatis a new manganese-based paramugnetic liver contrast agent Used in detection, characterization, localization and evaluation of lesions in the liver
Teslascan
47
whatis an iron oxide mixture and the only supramagnetic contrast agente available
Used to detect and diagnose liver lesions
Feridex
47
what is Technique used to organize the signal
Technique used for improving image quality
Used to reduce motion artifacts from the beating heart
The moving object is "frozen" at that phase of its at reducing umaga blurring
GATING
47
what type of parameter affect only the signal-producing portion of the image, which is normally patient anatomy and not background air.
Intrinsic parameters
47
what type of parameter influence the mechanics of data collection (e.g., voxel size) or other factors external to the tissue.
Extrinsic parameters
47
what it is any object that produces its own magnetic field that interacts with other magnetic fields.
Magnet
47
what it is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, cobalt, etc. and attracts or repels other magnets.
Magnetic fields
47
what it consists of positively charged protons and uncharged neutrons; particles collectively known as nucleons, which interact through a short-range attractive force that hold the nucleus together.
Nucleus
47
what it is small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909.
Nucleus
47
what it is an intrinsic particle property like mass or charge. Yet where this spin comes frm is such a mystery it’s dubbed.
Proton Spin
47
what In MRI refers to the rate of precession of the magnetic moment of the proton around the external magnetic field, The frequency of precession is related to the strength of teh magnetic field, B0.
Lamour Relationship
48
what it is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around 20 kHz to around 300 GHz.
Radiofrequency
48
what these are materials where the magnetic field is generated by the internal structure of the material itself.
Permanent magnet
48
what magnets which possess higher retentivity and coercivity and retain teh magnetic field foe longer period are called wht
Permanent magnet
48
what it is one that’s made out of a normal metal, that is copper or aluminm. The magnets that we build use what we call Florida Bitter magnet technology.
Resistive magnet
48
T1 in Mri means
longitudinal relaxation time
48
what is Hydrogen protons spin producing a magnetic field
a magnetic field creates an electrical chrage when it rotates past a coil of wire.
MAGNETIC RESONANCE IMAGING
48
2 TYPES OF MRI PARAMETERS:
INTRINSIC
EXTRINSIC
48
in MRI PARAMETERS:
what is uncontrolled by the operator
INTRINSIC
48
IN MRI PARAMETERS:
WHAT IS controlled by the operator
EXTRINSIC
49
WHAT ARE THE Intrinsic Parameters:
A. Proton Density or Spin Density
B. T1
49
WHAT IS is the quantity of resonating spins in a tissue. Proton Density weighted images are achieved by Long TR between pulses. PD Images are of low contrast.
Proton Density or Spin Density
49
what - the time required for the sum of magnetic moments to regain original orientation after RF excitation. It varies with its molecular lattice.
Spin-Lattice Relaxation Time
49
what the time required for the precessing spins to align with the constant external magnetic field to 63% of the maximum possible strength
Longitudinal Relaxation Time
49
wha t The wobble of the rotational axis of a spinning body about a stationary axis
Describes a cone
PRECESSION
49
what is increases as MF strength increase
Rate of precision
49
what is The time required for the thermally excited system to return to its equilibrium state.
Thermal Relaxation Time
49
what are the types of Extrinsic Parameters:
A. Repetition Time (TR)
B. Echo Time (TE)
C. Inversion Time (TI)
D. Flip Angle (FA)
49
whatis The time interval between pulse sequences. it is usually between 300-3000ms the longest of the parameters used to describe the sequence.
Repetition Time (TR)
49
what is the time between a 90 deg pulse and the echo during a spin- echo pulse sequence.
it is usually 10-100ms
always the shortest time used for a sequence.
can have multiple values.
Echo Time (TE)
49
what is the time between a 180 deg pulse and a 90 deg in an inversion recovery pulse sequence.
It is usually 200 2000ms
Inversion Time (TI)
49
what is Angle of inclination from the longitudinal axis.
Flip Angle (FA)
49
whatiss the time required after the precessing spins have aligned at an angle to the external magnetic field due to an RF pulse, to lose 63% of their coherence due to the interaction between the spins.
T2 as Spin-Spin Relaxation Time
49
what is the time required for the transverse magnetization to reduce its strength to 37% from its maximum.
T2 as Transverse Relaxation Time
50
what si A structure not normally present but visible as a result of a limitation or malfunction in the hardware or software of MRI device.
IMAGE ARTIFACT
50
MRI CONTRAINDICATION:
Cardiac pacemaker
Aneurysm clips
Claustrophobia
Metallic fragments in the eye
Cochlear implants
Internal drug infusion pumps
Neurostimulators
Bone growth stimulators
50
MRI OR CONVENTIONAL RADIOGRAPHY: Provides sectional images
MRI
50
MRI OR CONVENTIONAL RADIOGRAPHY:
No superimposition of structures
MRI
50
MRI OR CONVENTIONAL RADIOGRAPHY:
Clearly demonstrates structures even without contrast media
MRI
50
MRI OR CONVENTIONAL RADIOGRAPHY:
Can resolved relatively small contrast differences among tissue
MRI
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Contrast depends on the interaction of matter with electromagnetic forces
MRI
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Provides "flat" image
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY: Structures are superimposed
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Contrast media is required to clearly distinguished one anatomic structure or organ from one another
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Limited in its ability to distinguish types of tissue
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Cannot detect small attenuation changes
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Can only distinguish air, fat, bone, soft tissue, and metal
CONVENTIONAL RADIOGRAPHY
51
MRI OR CONVENTIONAL RADIOGRAPHY:
Contrast depends on differences of x-ray attenuation
CONVENTIONAL RADIOGRAPHY
