Final 200 Exam Practice Questions Flashcards

Question 1

Q

Question #1 : All of the following artifacts except ________ occur along the phase encoding axis.

Answer

A

Chemical shift

Question 2

Q

Question #2 : Magnetic susceptibility artifacts are more prominent with _____________ sequences.

Answer

A

Gradient echo

Gradient echo sequences are more susceptible to metallic artifacts due to the lack of 180º refocussing RF pulse which would reduce field inhomogeneities.

Question 3

Q

Question #3 : A remedy for a Gibbs truncation artifact would be:

Answer

A

Increase the number of phase encodings

To correct for Gibbs truncation artifact, increase the number of phase encodings or reduce the FOV (while maintaining matrix)

Question 4

Q

Question #4 : The largest ventricle in the heart is the _______ and is identified by Letter ____ in Image 66.

Answer

A

Left ventricle; D

Question 5

Q

Question #5 : Calculate the effective TR for a patient with a heart rate of 70 beats / min.

Answer

A

857 ms

If the heart rate is 70 beats per minute, the R-R interval (effective TR) would be calculated as such: 60,000 milliseconds (60 seconds per minute, and there are 1000 milliseconds per second) ÷ 70 (heart rate) which = 857 milliseconds TR.

Question 6

Q

Question #9 : The HEIGHT of a peak on an MR spectrum correlates to the _________ of a substance that was detected.

Question 7

Q

Question #10 : Contrast in Diffusion Weighted Imaging (DWI) depends on:
I. The degree to which molecular mobility is impaired (water restriction)
II. The sensitivity of the sequence to Brownian motion
III. T1 relaxation time
IV. The direction of water diffusion
V. T2 relaxation time

Answer

A

I, II and IV

Contrast in Diffusion Weighted Imaging (DWI) depends on the degree to which molecular mobility is impaired (water restriction), the sensitivity of the sequence to Brownian motion, and the direction of water diffusion.

Question 8

Q

Question #11 : The final result in a perfusion study is:

Answer

A

A set of calculated images which indicate various flow characteristics

The final result in a perfusion study is a set of calculated images which indicate various flow characteristics.

Question 9

Q

Question #12 : The final result in a spectroscopy study is:

Answer

A

A spectrum of specific detected metabolites

Spectroscopy (MRS) allows doctors to obtain biochemical information about the chemical components in tissues (metabolites) of the human body in a non-invasive way.

Question 10

Q

Question #13 : The imaging technique that employs a very rapid pulse sequence while the patient is at rest or performing a task is:

Answer

A

Functional MRI

The imaging technique that employs a very rapid pulse sequence while the patient is at rest or performing a task is known as Functional MRI.

Question 11

Q

Question #16 : If the TR in a gradient echo sequence is less than the T2 (or T2*), the resulting condition is known as:

Answer

A

Steady state

The condition of steady state occurs when the TR in a gradient echo is less than the T2 (or T2*), resulting in residual transverse magnetization at the time of the next excitation pulse

Question 12

Q

Question #17 : A gradient echo sequence in which all the remaining residual transverse magnetization is removed prior to the next excitation pulse is known as:

Answer

A

Incoherent or spoiled

A spoiled gradient echo sequence removes any residual transverse magnetization prior to the next excitation pulse.

Question 13

Q

Question #18 : In a Fast Spin Echo (FSE) sequence, acquired with a long TE, yielding T2 weighted images, scan time can be reduced by:

Answer

A

Using longer ETL

Longer ETL (echo train lengths) shorten overall scan times in Fast Spin Echo (FSE) sequences.

Question 14

Q

Question #19 : In a Fast Spin Echo (FSE) sequence, acquired with a short echo time (TE), yielding T1 or PD weighted images, blurring can be reduced by:

Answer

A

Using shorter ETL

In a Fast Spin Echo sequence, increasing the # ETL (echo train lengths) can lead to an increase in blurring.

Question 15

Q

Question #20 : The structures that comprise the rotator cuff in the shoulder are:
I. Deltoid muscle
II. Subscapularis muscle and tendon
III. Infraspinatus muscle and tendon
IV. Teres minor muscle and tendon
V. Supraspinatus muscle and tendon
VI. Trapezius muscle and tendon

Answer

A

II, III, IV and V

The rotator cuff is comprised of the subscapularis muscle and tendon, infraspinatus muscle and tendon,teres minor muscle and tendon and the supraspinatus muscle and tendon

Question 16

Q

Question #21 : T2 weighted FLAIR (fluid attenuated inversion recovery) sequences are typically used for evaluation of:

Answer

A

White matter disease

T2 weighted FLAIR (fluid attenuated inversion recovery) sequences are typically used for evaluation of periventricular white matter.

Question 17

Q

Question #22 : Short TAU inversion recovery (STIR) sequences are typically used for the evaluation of all the following EXCEPT:

Answer

A

Fluid (CSF)

Short TAU inversion recovery (STIR) sequences are typically used for the evaluation of compression fracture, lesions within retro-orbital fat, musculoskeletal contusions and fat suppression.

Question 18

Q

Question #23 : If the pulse sequence shown in Image 77 were a fast spin echo sequence, the number of lines of k-space filled for each TR period would be:

Answer

A

2

In a fast spin echo sequence, multiple echoes are used to fill multiple lines of k-space for each TR period, thus reducing scan time by the number of echoes. Image 77’s example would shorten the overall scan time by a factor of 2, for each 180° echo.

Question 19

Q

Question #24 : When a gradient echo sequence is selected for fast, breath hold dynamic contrast-enhanced imaging of the abdomen, _____________ is utilized.

Answer

A

Spoiling

To reduce the steady state (T2*) effect, a technique known as “spoiling” can be employed to allow for fast scans with T1 contrast. RF spoiling occurs when additional RF pulses are used to “spoil away” the steady state effect (residual transverse magnetization) before the next excitation, yielding T1 contrast for dynamic imaging of organs or CE MRA sequences.

Question 20

Q

Question #25 : Gradient echo sequences requiring high signal from fluid are known as all of the following EXCEPT:

Answer

A

Incoherent gradient echo

Gradient echo sequences requiring high signal from fluid are known as T2* gradient echo, Steady-state gradient echo or coherent gradient echo. Incoherent gradient echo (or spoiled gradient echo) sequences yield T1 contrast due to the removal of residual transverse magnetization before the next excitation.

Question 21

Q

Question #26 : Dynamic enhanced MRA sequences of the mesenteric arteries are performed using:

Answer

A

Incoherent gradient echo

Gradient echo sequences requiring high signal from fluid are known as T2* gradient echo, Steady-state gradient echo or coherent gradient echo. Incoherent gradient echo (or spoiled gradient echo) sequences yield T1 contrast due to the removal of residual transverse magnetization before the next excitation. This fast T1 contrast can be utilized in dynamic MRI imaging of the abdominal organs or CE MRA techniques.

Question 22

Q

Question #27 : Gradient echo sequences can yield either T1 or T2* characteristics, with influences caused by all of the following EXCEPT:

Answer

A

Inversion time

Gradient echo sequences can yield either T1 or T2* characteristics, with influences caused by susceptibility, Chemical shift, and inhomogeneities.

Question 23

Q

Question #28 : Which of the following field strengths would require the shortest TI time to suppress the signal from fat when performing a STIR sequence in an MRI of the ankle?

Question 24

Q

Question #29 : If the desire is to null the signal from a specific tissue using an inversion recovery sequence, the inversion time (TI) selected should be ______ of the T1 relaxation time of that tissue.

Answer

A

69%

If the desire is to null the signal from a specific tissue using an inversion recovery sequence, the inversion time (TI) selected should be 69% of the T1 relaxation time of that tissue.

Question 25

Q

Question #30 : When parallel imaging techniques are utilized, a low resolution __________ is acquired prior to the acquisition.

Answer

A

Calibration scan

When parallel imaging techniques are utilized, a low resolution calibration scan (reference tissue scan) is acquired prior to the acquisition.

Question 26

Q

Question #31 : In a Fast Spin Echo sequence, the number of shots is calculated by:

Answer

A

Phase encodings / ETL

In a Fast Spin Echo sequence, the number of shots is calculated by #Phase encodings / ETL.

Question 27

Q

Question #32 : In a medical malpractice lawsuit, the ______ must be able to prove medical malpractice.

Answer

A

Patient plaintiff

Question 28

Q

Question #33 : Healthcare workers generally practice ___________, which states the “goal is to do no harm.”

Answer

A

Beneficence

Healthcare workers generally practice beneficence, which states the “goal is to do no harm.”

Question 29

Q

Question #34 : Referencing the White Paper on MRI safety, individuals identified as “Level 2” personnel include:

Answer

A

Those with extensive MRI safety training, including the magnetic, gradient and RF fields

Those with extensive MRI safety training, including the magnetic, gradient and RF fields of an MR system are identified as “Level 2” personnel

Question 30

Q

Question #35 : Referencing the White Paper on MRI safety, individuals identified as “Level 1” personnel include:

Answer

A

Those with limited MRI safety training

Those with limited MRI safety training are identified as “Level 1” personnel

Question 31

Q

Question #36 : Which of the following is NOT a type of fomite found in an MRI environment?

Answer

A

Injection syringe

A fomite is an object that carries microorganisms from one person to another via indirect contact.

Question 32

Q

Question #37 : Diseases, such as malaria, in which microorganisms are transferred via an insect, come under the classification of __________ infections.

Answer

A

Vector borne

Diseases, such as malaria, in which microorganisms are transferred via an insect, come under the classification of Vector borne infections

Question 33

Q

Question #38 : Which type of blood cell is responsible for phagocytosis?

Answer

A

Leukocyte

A leukocyte is a white blood cell. Phagocytosis occurs when microorganisms enter the body and fluids carrying white blood cells travel to the site to destroy them.

Question 34

Q

Question #39 : The source of infection where pathogens thrive in numbers sufficient to cause a threat is known as a:

Answer

A

Reservoir

The source of infection where pathogens thrive in numbers sufficient to cause a threat is known as a reservoir.

Question 35

Q

Question #40 : Droplet contamination frequently occurs via:

Answer

A

Coughing

Droplets can be spread by sneezing, coughing and speaking, and depositing the droplets into the mucous membranes of the face. Droplets travel short distances of 3 feet or less and do not remain suspended in air.

Question 36

Q

Question #41 : Referencing the Centers for Disease Control and Prevention (CDC), what type of isolation precautions should be used for HIV-positive patients in the MRI suite?

Answer

A

Standard (universal)

Adhere to STANDARD precautions for ALL patients at ALL times for safety and infection control best practices.

Question 37

Q

Question #42 : During movement or transfer of patients, a urinary collection bag should be placed:

Answer

A

Below the level of the urinary bladder

During movement or transfer of patients, a urinary collection bag should be placed below the level of the urinary bladder. Urinary tract infections acquired nosocomially are often due to the incorrect placement of the urinary collection bag.

Question 38

Q

Question #43 : Another term used for “fever” is:

Answer

A

Febrile

The term febrile is defined as pertaining to or marked by fever; feverish. For example, a febrile seizure or convulsion is a seizure caused by a high fever.

Question 39

Q

Question #44 : A technologist may be permitted to administer oxygen in an emergency situation. The most common rate used is:

Answer

A

2L/min

Oxygen is considered a medication and in order to be administered, must be prescribed by a physician. A technologist may administer oxygen in an emergency situation. The most frequent rate used is 2L/min.

Question 40

Q

Question #45 : In a dual contrast spin echo sequence with echo times of 25ms and 90ms, the second echo image has __________ than the first echo image
I. more T2 contrast
II. lower signal-to-noise ratio
III. more T1 contrast

Answer

A

I and II only

Longer TE’s provide more T2 contrast, but reduced signal-to-noise ratios

Question 41

Q

Question #46 : As the TE is increased,
I. The available number of slices is increased
II. The available number of slices is decreased
III. SNR increases
IV. T1 contrast is maximized

Answer

A

II only

As the TE is increased, the available number of slices are decreased (longer TE means fewer slices can fit into the TR period)

Question 42

Q

Question #47 : Which of the following sequences is the most insensitive to magnetic field inhomogeneity?

Answer

A

Spin echo

Spin echo sequences contain 180° RF refocusing pulse(s), which aid in correcting for local field inhomogeneities, therefore making them the most INSENSITIVE to chemical shift, susceptibility or inhomogeneity.

Question 43

Q

Question #48 : As the TR is increased,
I. SNR is increased
II. Available number of slices is increased
III. T2 information is maximized

Answer

A

I and II only

As the TR is increased, SNR is increased and the available number of slices is increased.

Question 44

Q

Question #49 : CSF suppression is performed with which type of technique?

Answer

A

FLAIR

FLAIR (Fluid Attenuated Inversion Recovery) is a technique that nulls the signal from CSF in order to achieve better white matter visualization

Question 45

Q

Question #58 : What element in the body is the principal nucleus utilized in clinical MR imaging?

Question 46

Q

Question #59 : The extent to which a material or tissue becomes magnetized in an external magnetic field is called:

Answer

A

Magnetic susceptibility

Question 47

Q

Question #60 : The energy used to form MRI images is ____________ the patient’s tissues.

Answer

A

Emitted from

Unlike other imaging modalities, MRI obtains signal information via the energy emitted from the patient’s tissues following RF excitation pulses.

Question 48

Q

Question #61 : The _________ is defined as the resonant frequency, and is equal to the product of the magnetic field and the gyromagnetic ratio.

Answer

A

Precessional frequency

The precessional frequency is defined as the resonant frequency, and is equal to the product of the magnetic field and the gyromagnetic ratio.

Question 49

Q

Question #62 : Force on an object in an magnetic environment depends on:
I. Mass of the object
II. Strength of the magnetic field
III. Strength of the RF field
IV. Ferromagnetic properties of the object

Answer

A

I, II and IV

Force on an object in an magnetic environment depends on the mass and the ferromagnetic properties of the object, as well as the strength of the magnetic field.

Question 50

Q

Question #63 : A magnetic vector possesses attributes of both __________ and _____________.

Answer

A

Magnitude; direction

Question 51

Q

Question #64 : Immediately following the application of the 90° RF pulse, the precessing protons:

Answer

A

A and C only - begin to precess in phase; tip into the transverse plane.

Immediately following the application of the 90° RF pulse, the precessing protons begin to precess in phase and tip into the transverse plane.

Question 52

Q

Question #69 : Image 43 is an example of an MR angiography of the abdominal aorta and runoff of the lower extremities. This was acquired with dynamic contrast enhancement and:

Answer

A

Stepping table motion from the abdomen down to the feet following the contrast injection

Question 53

Q

Question #70 : When imaging the female pelvis, the most optimal view for evaluation of the ovaries is the:

Question 54

Q

Question #71 : When imaging the female pelvis, the most optimal view for evaluation of the uterus is the:

Question 55

Q

Question #87 : The ___________ valve lies between the left atrium (LA) and the left ventricle (LV).

Question 56

Q

Question #91 : Which of the following parameter adjustments help to improve SNR in an MR image?
I. Increase TR
II.Reduce Phase Matrix
III. Reduce Pixel Size
IV. Increase FOV
V. Reduce rBW
VI. Increase rBW
VII. Increase NSA
VIII. Decrease NSA
IX. Increase ETL
X. Decrease ETL

Answer

A

I, II, IV, V, VII and X

Increasing TR, Reducing the Phase Matrix, Increasing the FOV, Reducing (narrowing) the receive Bandwidth, Increasing NEX/NSA and Reducing the #ETL all help to improve SNR in an MR image.

Question 57

Q

Question #92 : Which of the following parameter adjustments reduce the overall SNR in an MR image?
I. Decrease TR
II.Reduce Phase Matrix
III. Reduce Pixel Size
IV. Decrease FOV
V. Reduce rBW
VI. Increase rBW
VII. Increase NEX
VIII. Decrease NEX
IX. Increase ETL
X. Decrease ETL

Answer

A

I, III, IV, VI, VIII and IX

A Decrease in TR, Reduction in Pixel Size, Decrease in FOV, Increase (widening) of the receiver Bandwidth, Decrease in NEX and an Increase in #ETL all negatively impact SNR in an MR image.

Question 58

Q

Question #93 : Fat has a _______ T1 relaxation time and a ________ T2 relaxation time.

Answer

A

Short; short

Fat has a short T1 relaxation time and a short T2 relaxation time

Question 59

Q

Question #94 : Water has a __________ T1 relaxation time and a ________ T2 relaxation time.

Answer

A

Long; long

Water has a long T1 relaxation time and a long T2 relaxation time.

Question 60

Q

Question #95 : Which of the following is NOT affected by changing the slice thickness?

Answer

A

The T2 contrast

Echo Time (TE) is the controlling factor of T2 weighting/contrast in an image; slice thickness does nothing to alter the T2 information.

Question 61

Q

Question #96 : Which parameter combination will yield the best spatial resolution?

Answer

A

3mm slice thickness, 256 x 256 matrix

Thinner slices yield improved spatial resolution(detail), in addition to smaller pixel size (higher phase matrix)

Question 62

Q

Question #97 : In a fast spin echo sequence with a 25 cm FOV, 224 x 320 matrix, TR 2500, 100 TE, 3mm slice thickness, 12 ETL and 4 NEX, the scan time would be:

Answer

A

3 minutes 7 seconds

Scan time formula: TR x Phase Matrix x NEX ÷ ETL = total in milliseconds, then ÷ 1000 to achieve scan time in seconds. In this example, TR2500 x 224ph encodings x 4NEX / 12ETL /1000. Be careful if you divide by 60 to achieve the scan time in decimal format (This example computes to 186.6 seconds, if you divide by 60 you get 3.11 seconds, which is 3 minutes 7 seconds, not 3 minutes 11 seconds)

Question 63

Q

Question #98 : Reducing the FOV (field of view) only will result in:

Answer

A

Decreased signal-to-noise

A reduction in FOV will yield a decrease in SNR, but an increase in spatial resolution.

Question 64

Q

Question #99 : The smallest object that can be resolved in an image acquired with a 24cm FOV and a 272 x 272 matrix is _________ mm.

Answer

A

0.88mm

Convert the cm of the FOV into mm by multiplying 24 x 10. 240 / 272 = 0.88mm

Answer 59

A

5min 21sec

3D scan time formula: TR x Phase Matrix x NEX x # slices

Answer 60

A

0.88mm

An isotropic voxel has equal measurements in all three dimensions (phase, frequency and slice direction) FOV/Matrix = 0.88mm

Answer 61

A

0.81 x 0.81 mm

FOV ÷ Matrix = pixel size….. 260 ÷ 320 = 0.81mm

Answer 62

A

Reduction in ETL

Reducing the # ETL increases overall scan time

Answer 63

A

Increase in TE

An increase in TE will yield a decrease in SNR

Answer 64

A

A and/or C only

Acquiring a bit more than half the phase k-space samples, then interpolating the data with zeroes for the remaining half is a technique known as Half Fourier, or Zero Fill.

Answer 65

A

A, D and E only

Reducing the number of lines filled in k-space reduces the number of phase encoding steps, resulting in shorter scan time, an increase in overall SNR, but a decrease in spatial resolution.

Answer 66

A

Low energy, nonionizing radiation

RF energy used in MRI is classified as low energy, nonionizing radiation.

Answer 67

A

4

If the flip angle is doubled, RF deposition increases by a factor of 4.

Answer 68

A

1.98mm3

To calculate voxel volume, first determine pixel area. FOV/matrix x FOV/matrix = pixel area. Pixel area x slice thickness = voxel volume. 240/272 x 240/320 = 0.66 mm2 (pixel area). 0.66 x 3 = 1.98mm3

Answer 69

A

0.62 mm2

FOV/matrix x FOV/matrix = pixel area. 360/408 x 360/512 = 0.62 mm2.

Answer 70

A

Partial or fractional echo

Partial or fractional echo is when only half the views of k-space are filled in the frequency axis, an acceleration technique used to shorten TR and TE.

Answer 71

A

Decreases

As the number of phase encodings is increased from 256 to 512, SNR (signal to noise ratio) decreases (less protons per voxel)

Answer 72

A

Frequency encoding

The readout gradient is usually turned on during the sampling or readout of the peak echo and also during frequency encoding.

Answer 73

A

Increases susceptibility artifact

A narrow receiver bandwidth increases susceptibility artifact, and should never be used in the presence of metal implants.

Answer 74

A

Slices will be thin

Steep slice select gradient slope yields thin slice thickness

Answer 75

A

Multi-Planar reconstruction (MPR)

The MPR function enables the user to create additional images from an acquired 3D data set.

Answer 76

A

Fourier transform

The process that digitizes the MR signals is known as Fourier transform.

Answer 77

A

FOV, slice thickness and matrix

FOV, slice thickness and matrix are the parameters used to make adjustments to voxel volume.

Answer 78

A

Flip angle; maximum

The Ernst angle can be defined as the optimal flip angle that yields the maximum signal for a particular spin in the least amount of time.

Answer 79

A

I, III, V, VII and VIII

Decreasing TR, increasing the #ETL, Decreasing NEX, enabling half-scan and Increasing parallel imaging factor all have an impact on shortening overall scan times in an MR pulse sequence.

Answer 80

A

II, IV, VI and IX

Increasing TR, Decreasing the # ETL, Increasing NEX and Decreasing the parallel imaging factor all play a role in lengthening scan time in an MR pulse sequence.

Answer 81

A

Sagittal

Arnold–Chiari malformation, or often simply Chiari malformation,consists of a downward displacement of the cerebellar tonsils through the foramen magnum and is best visualized with the Sagittal plane.

Answer 82

A

Gradient echo

Due to the lack of 180° RF refocusing pulse, the gradient echo sequence is more susceptible to magnetic field inhomogeneities, such as hemosiderin from blood products. The hemosiderin is highly magnetic because it is principally iron.

Answer 83

A

FLAIR

FLAIR (FLuid Attenuated Inversion Recovery) sequences suppress the signal from CSF to detect small white matter lesions, tumors, and evaluation of stroke.

Answer 84

A

Eyes

The medial rectus muscle is a muscle in the orbit. As with most of the muscles of the orbit, it is innervated by the inferior division of the oculomotor nerve (CN III)

Answer 85

A

Mandibular fossa and mandibular condyle

In the TMJ’s, the articular disc lies between the mandibular condyle and the mandibular fossa.

Answer 86

A

Aqueduct of Sylvius

The cerebral aqueduct, or Aqueduct of Sylvius, is a CSF containing structure that connects the third ventricle to the fourth ventricle.

Answer 87

A

Sylvian fissure

The Sylvian fissure divides the frontal and parietal lobes from the temporal lobes.

Answer 88

A

Superior sagittal sinus

The superior sagittal sinus (also known as the superior longitudinal sinus), within the human head, is an unpaired area along the attached margin of falx cerebri. This sinus runs the length of the falx cerebri.

Answer 89

A

T1 weighted

When performing MRI to rule out brain tumors, the weighted images acquired to evaluate the extent of lesion involvement, after injection of gadolinium, are T1 weighted.

Answer 90

A

192

If a 192 phase resolution is required, the TR must then be repeated 192 times (for 1 NEX).

Answer 91

A

Prior to frequency encoding

The phase encoding step is performed prior to frequency encoding.

Answer 92

A

Coronal

Structures that lie medial and lateral, anatomically, are well visualized in the coronal plane. Therefore, the medial and lateral collateral ligaments of the knee are best visualized in the coronal plane.

Answer 93

A

Coronal

The Triangular FibroCartilage Complex (TFCC) of the wrist is best seen in the coronal imaging plane.

Answer 94

A

Long T2

On a T2 weighted image, edema appears bright because fluid has a long T2 relaxation time.

Answer 95

A

Splenic duct

Answer 96

A

Pancreas

Well or intermediately differentiated Pancreatic Neuroendocrine Tumors are sometimes called islet cell tumors, and are diagnosed with an abdominal MRI exam with attention to the pancreas.

Answer 97

A

C3-4 disc space

The common carotid artery bifurcation can be found at the level of the C3-4 disc space of the cervical spine.

Answer 98

A

Superior to slice group

In order to acquire an intracranial arterial blood flow MRA, a presaturation pulse would be applied superior to the slice group in in order to null signal from intracranial venous blood flow.

Answer 99

A

Image larger areas without saturation of flowing blood

2D TOF is generally utilized when larger regions of anatomy are required to be imaged, with typically thicker slices than 3D TOF.

Answer 100

A

Out of phase

Out of phase TE’s minimize signals from background stationary tissues in time of flight MR angiography.

Answer 101

A

Velocity of the flowing blood

The velocity or speed of the vessel(s) of interest determines the signal intensities in phase contrast MR angiography (PCA).

Answer 102

A

Celiac artery

The first major branch of the abdominal aorta is the celiac trunk, which branches into the gastric, hepatic and splenic arteries.

Answer 103

A

Celiac, superior mesenteric, renal, inferior mesenteric

The branches of the abdominal aorta, from proximal (superior) to distal are: Celiac, superior mesenteric, renal, and inferior mesenteric arteries.

Answer 104

A

VENC

VENC (velocity encodings) might be adjusted in an elderly (geriatric) patient during a PCA (phase contrast angiography) MRA sequence to compensate for changes in the rate of blood flow.

Answer 105

A

Spine

The ligamenta flava (singular, ligamentum flavum, Latin for yellow ligament) are ligaments which connect the laminae of adjacent vertebrae in the spine, all the way from the axis to the first segment of the sacrum (C2 to S1).

Answer 106

A

Hypointense to the spinal cord

On T1 weighted images of the spine, the CSF (cerebrospinal fluid) appears hypointense (low signal intensity) to the spinal cord.

Answer 107

A

Radiofrequency coils

The RF (radiofrequency) coils are closest to the patient, the primary component causing RF absorption in the patient

Answer 108

A

Make the B0 field as homogenous as possible

The additional magnetic fields (produced by shimming) add to the overall magnetic field of the superconducting magnet in such a way that the total B0 field becomes more homogeneous.

Answer 109

A

Gauss

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as Gauss.

Answer 110

A

Superconducting windings within the MR scanner, reducing the fringe magnetic field

Active shielding requires the implementation of superconducting windings within the construction of the MR scanner to oppose a portion of the magnetic field.

Answer 111

A

Steel; passive

Steel could be used to line the walls and/or floors of the MR magnet room to reduce the fringe field, and is defined as passive shielding.

Answer 112

A

Time varying magnetic fields (TVMF – gradient)

Time varying magnetic fields (TVMF – gradient)have been documented to cause muscle contractions, cardiac arrhythmias, mild cutaneous sensations and visual light flashes.

Answer 113

A

Time it takes for the gradient to reach its full amplitude

The gradient rise time is defined as the time it takes for the gradient to reach its full amplitude.

Answer 114

A

Rate of speed of ascent or descent of a gradient from zero to its maximum amplitude

The gradient slew rate is defined as the rate of speed of ascent or descent of a gradient from zero to its maximum amplitude.

Answer 115

A

Parts per million

Magnetic field inhomogeneity is expressed in parts per million (ppm)

Answer 116

A

Parallel imaging

A recent development in MRI technology has been the development of sophisticated multi-element phased array coils which are capable of acquiring multiple channels of data in parallel. This ‘parallel imaging’ technique uses unique acquisition schemes that allow for accelerated imaging.

Answer 117

A

1%

Less than 1% patients are reported to have allergic reactions to gadolinium contrast agents during MRI procedures.

Answer 118

A

16mL

Divide 176 lbs by 2.2 (lbs per kg), then multiply the kg (80) by 0.2 ml/kg = 16mL

Answer 119

A

Short

A short TR (time between excitation pulses) is necessary to produce an image based on differences in T1.

Answer 120

A

TR

Intrinsic parameters in tissues are those that are specific to each tissue, inherent, and cannot be changed, such as ADC, T1/T2 time, specific proton density, and flow.

Answer 121

A

Precessional frequency of fat

Chemical or spectral fat suppression techniques suppress fat signal based on the precessional frequency of fat.

Answer 122

A

Delayed images

Hemangiomas in the liver are typically venous-fed, benign lesions, and are best visualized with delayed enhancement images. Liver cancers, on the other hand, are typically arterial-fed and are best seen on first pass dynamic images.

Answer 123

A

Spatial presaturation

In an MRA sequence, the removal of signal from vessels is accomplished by spatial presaturation.

Answer 124

A

C and D

The longer the TE, the more time given for intravoxel dephasing, resulting in signal loss from within the vessel. Larger voxels lead to an increase in inhomogeneities within the voxel, increasing intravoxel dephasing and reducing signal intensity.

Answer 125

A

Increases SNR up to the Ernst angle

Increasing the flip angle increases SNR up to the Ernst angle.

Answer 126

A

Less T1 information

Reducing the flip angle yields images with less T1 information.

Answer 127

A

Decreased T2 information

Reducing the TE yields images with decreased T2 information.

Answer 128

A

Main magnet

The MRI system component that produces the magnetization of proton spins (alignment) is known as the main magnet.

Answer 129

A

Gradient system

The MRI system component that provides the ability to perform spatial encoding is the gradient system.

Answer 130

A

Turns of wire

In a superconducting magnet, the magnetic field strength is increased by increasing the turns of wire, current in the wires, or by reducing the spacing between the wires.

Answer 131

A

Solenoids

Permanent magnets with a vertical magnetic field use surface coils that are solenoids because the secondary magnetic field (B1)created by the RF coil must be perpendicular to the orientation of B0.

Answer 132

A

A, B and D only

The transmit bandwidth of the RF pulse affects the slice thickness, which has an effect on resolution and the overall SNR in the MR image.

Answer 133

A

I, II and IV

A thin slice thickness is achieved through the utilization of a steep, high amplitude slice select gradient, and a narrow transmit bandwidth (tBW).

Answer 134

A

I and III only

The receiver bandwidth (rBW) affects the signal-to-noise ratio (SNR) in the image, but also has an effect on chemical shift (decreasing the receiver bandwidth increases chemical shift)

Answer 135

A

Radiofrequency coil

The B1 magnetic field is produced by a radiofrequency coil.

Answer 136

A

Turning the shim coil off and on rapidly

Shimming in MRI can be performed by adding current to the gradient coils (gradient shimming), adding metal to different coils within the shim coil (passive shimming) or changing the current in the shim coil (active shimming)

Answer 137

A

Iatrogenic

An iatrogenic event or reaction is one caused by a medical professional, whether it be negligence, drug interactions, or even erroneous medical advice.

Answer 138

A

3.0W/kg for 10 minutes

The 2003 FDA revision on RF absorption limits the absorption to 3.0W/kg for 10 minutes for the HEAD.

Answer 139

A

Metastatic lesions (in the cord) enhance and normal cord does not

When imaging the spine, to rule out metastatic lesions of the spinal cord, contrast enhancement is used with T1 weighted images because metastatic lesions (in the cord) enhance and normal cord does not.

Answer 140

A

3.5

The difference in chemical shift is approximately 3.5 parts-per-million.

Answer 141

A

1.5T

The T1 time of fat at 1.5 Tesla is approximately 240 with a null point of 160 ms.

Answer 142

A

450 TR; 30º flip angle

450 TR; 30º flip angle combination would yield a T2 weighted gradient echo.

Answer 143

A

Acquisition voxel should be isotropic

To produce a high quality reformatted image, the acquisition voxel should be isotropic.

Answer 144

A

Elliptic centric

Collecting the low frequency (high amplitude signal) data points in k-space at the start of the scan (in a spiral fashion) is known as elliptic centric k-space filling.

Answer 145

A

TOF MRA; PC MRA

Answer 146

A

A train of gradient echoes

An EPI (echo planar imaging) sequences can be best described as a “train” of gradient echoes.

Answer 147

A

A 180° pulse followed by a 90°/180° combination

An IR (inversion recovery) sequence can be best described as a 180° pulse followed by a 90°/180° combination.

Answer 148

A

A train of spin echoes

A FSE (fast spin echo) sequence can be best described as a “train” of spin echoes.

Answer 149

A

B and C -

Single-order gradient moment nulling only compensates for first-order motion, such as flow with constant velocity.

Answer 150

A

4

Remember, the FOV is measured in phase and frequency dimensions, therefore reducing the FOV in half will reduce the phase AND frequency dimensions EACH by 2, for a total reduction of a factor of 4.

Answer 151

A

487 ms

Heart Rate 90bpm, Trigger delay 50ms, Trigger window 10%, what is the available imaging time?
60000 ÷ 90 = 667ms. 667 – (100 <15% of 667> + 80 —180) = 487 ms total available imaging time.

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