mri quiz wrong answers

Which of the following implants would be considered acceptable for an MRI scan at 1.5Tesla? You selected: Ferrous cerebral aneurysm clips The correct answer for this question is: Heart valves

Question #10 : The effects of time varying magnetic fields can include all of the following EXCEPT: You selected: Acoustic damage and/or hearing loss The correct answer for this question is: Warmth and/or increase in body temperature The effects of time varying magnetic fields can include peripheral nerve stimulation, acoustic damage/hearing loss, magnetophosphenes ("seeing stars").

Which of the following sequences would be more at risk for the effects that time varying magnetic fields can cause? You selected: GE The correct answer for this question is: EPI EPI (Echo Planar Imaging) sequences can have more of a detrimental effect on patients with regards to time varying magnetic fields.

A technique utilized to reduce the MRI scan time which requires the use of an array coil is: You selected: Rectangular field of view The correct answer for this question is: 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.

Utilization of surface coils yields all of the following EXCEPT: You selected: Localized, smaller FOV capability The correct answer for this question is: Increased FOV capabilty Utilization of surface coils yields a more localized, smaller FOV (field of view) capability, with increased SNR, thus providing opportunity for thinner slices on most systems.

The strength of the gradient over a specific distance is known as the: You selected: Flux lines The correct answer for this question is: Slew rate The strength of the gradient over a specific distance is known as the slew rate.

The duty cycle is defined as the: You selected: Time it takes for the gradient to reach its full amplitude The correct answer for this question is: Time the gradients are on during a TR period The duty cycle is defined as the time the gradients are on during a TR period

________ may be defined as a personal injury; or as "a civil action other than a breach of contract." You selected: Statutory law The correct answer for this question is: Tort Tort may be defined as a personal injury; or as "a civil action other than a breach of contract."

FA is short for: You selected: Flip angle The correct answer for this question is: A or C

mmol is short for: You selected: multimillion The correct answer for this question is: millimol

MR technique which quantitatively assesses the mechanical properties of tissues, based on the propagation of shear waves: You selected: Magnetic resonance spectroscopy (MRS) The correct answer for this question is: Magnetic resonance elastography (MRE) Magnetic resonance elastography (MRE) – MR technique which quantitatively assesses the mechanical properties of tissues, based on the propagation of shear waves.

The linear increased or decreased change in the magnetic field of a certain orientation is defined as a _________. You selected: Flip angle The correct answer for this question is: Gradient Gradient -- The linear increased or decreased change in the magnetic field of a certain orientation.

__________ can be defined as the signal strength differences between two adjacent tissue types. You selected: Fat saturation The correct answer for this question is: Contrast Contrast can be defined as the signal strength differences between two adjacent tissue types.

___________ is a term used to describe the adjustment of the current within the shim coils on a per patient or per sequence basis. You selected: Passive shimming The correct answer for this question is: Active shimming Active shimming is a term used to describe the adjustment of the current within the shim coils on a per patient or per sequence basis, for the purposes of achieving uniform fat suppression or optimal prescan calibrations.

Consistent room temperature of 65-75°F, humidity of 50-70%, and sufficient air flow in the MR scan room is recommended to: You selected: Reduce the cryogen boil off rate The correct answer for this question is: Make patients less vulnerable to the RF heating effects

The purpose of shimming the magnet is to: You selected: make the B1 field as homogenous as possible The correct answer for this question is: 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

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as: You selected: Tesla The correct answer for this question is: Gauss The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as Gauss.

The intensity limit for a static magnetic field in clinical use is limited by the Food and Drug Administration (FDA) to _____________? You selected: 7 Tesla The correct answer for this question is: 4 Tesla The intensity limit for a static magnetic field in clinical use is limited by the Food and Drug Administration (FDA) to 4.0 tesla (T) strength.

Doubling field strength will result in what impact on SAR potential, if any? You selected: Double SAR The correct answer for this question is: Quadruple SAR SAR is proportional to the power of 2 for the resonant frequency – doubling field strength results in fourfold increase in SAR potential.

Transmit gain is a quality measure evaluating for? You selected: Low contrast spatial resolution The correct answer for this question is: Accuracy of flip angles

All of the following are non-ferrous substances EXCEPT: You selected: Plastic The correct answer for this question is: Iron

_________ magnets can be “shut off” the quickest in case of an emergency. You selected: Superconducting The correct answer for this question is: Resistive Resistive magnets can be “shut off” the quickest in case of an emergency.

All of the following are true regarding RF EXCEPT: You selected: The RF pulse stimulates the protons into parallel or anti-parallel alignment The correct answer for this question is: RF converts FID into an echo

A magnetic vector possesses attributes of both __________ and _____________. You selected: Strength; magnitude The correct answer for this question is: Magnitude; direction

Hydrogen protons in the anti-parallel state are referred to as: You selected: Both A and B The correct answer for this question is: Both A and C Hydrogen protons in the anti-parallel state are referred to as spin down and/or high energy spins

Immediately following the application of the 90° RF pulse, the precessing protons: You selected: Begin to precess in phase The correct answer for this question is: Both A and B Immediately following the application of the 90° RF pulse, the precessing protons begin to precess in phase and tip into the transverse plane.

Immediately following the application of the 90° RF pulse, the transverse magnetization is: You selected: Zero The correct answer for this question is: Non-zero Immediately following the application of the 90° RF pulse, the transverse magnetization is Non-zero.

Image 82 was acquired at what field strength? You selected: 3.0 Tesla The correct answer for this question is: 1.5 Tesla The center frequency (Resonance freq) at 1.5 Tesla is ~63.86 mHz.

Image 91 was acquired at what field strength? You selected: 3.0 Tesla The correct answer for this question is: 1.5 Tesla Center frequency (resonance freq) at 1.5 Tesla is ~63.86 MHz.

How well a material attracts the imaginary lines of the magnetic field is defined as: You selected: Magnetic susceptibility The correct answer for this question is: Magnetic permeability Magnetic permeability – how well a material attracts the imaginary lines of the magnetic field

At 1 Tesla the frequency difference between that of fat and water is approximately: You selected: 42.57 MHz The correct answer for this question is: 147 Hz At 1 Tesla the frequency difference between that of fat and water is approximately 147 Hz

Image 92 was acquired at what field strength? You selected: 3.0 Tesla The correct answer for this question is: 1.0 Tesla The center frequency (resonance freq) for a 1.0 Tesla MR system is ~42.57 MHz.

The final result in a perfusion study is: You selected: A spectrum of specific detected metabolites The correct answer for this question is: 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.

The final result in a spectroscopy study is: You selected: A set of calculated images which indicate various flow characteristics The correct answer for this question is: 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.

Dynamic enhanced MRA sequences of the mesenteric arteries are performed using: You selected: Steady-state gradient echo The correct answer for this question is: 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.

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? You selected: 1.5T The correct answer for this question is: 0.5T

In a Fast Spin Echo sequence, the number of shots is calculated by: You selected: TR / #Phase encodings The correct answer for this question is: #Phase encodings / ETL In a Fast Spin Echo sequence, the number of shots is calculated by #Phase encodings / ETL.

Immediately following the application of the 90° RF pulse, the precessing protons: You selected: Begin to precess in phase The correct answer for this question is: A and C only Immediately following the application of the 90° RF pulse, the precessing protons begin to precess in phase and tip into the transverse plane.

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: You selected: Stepping table motion from the feet up to the abdomen following the contrast injection The correct answer for this question is: Stepping table motion from the abdomen down to the feet following the contrast injection

_______ is when only half the views of k-space are filled in the frequency axis. You selected: Parallel imaging The correct answer for this question is: 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.

The phase encoding step is performed: You selected: During frequency encoding The correct answer for this question is: Prior to frequency encoding The phase encoding step is performed prior to frequency encoding.

In what orientation would a tear of the collateral ligaments of the knee be best visualized? You selected: Sagittal The correct answer for this question is: 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.

A disadvantage of TOF MRA is high signal in some background tissues. To minimize signal from background tissues, TE should be selected that enable the signals from fat and water to be: You selected: Nulled The correct answer for this question is: Out of phase Out of phase TE's minimize signals from background stationary tissues in time of flight MR angiography.

The purpose of shimming the magnet is to: You selected: Make the B1 field as homogenous as possible The correct answer for this question is: 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.

A technique utilized to reduce the MRI scan time which requires the use of an array coil is: You selected: Rectangular FOV The correct answer for this question is: 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.

All of the following are examples of INTRINSIC contrast parameters in tissues EXCEPT: You selected: ADC (apparent diffusion coefficient) The correct answer for this question is: 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.

In an MRA sequence, the removal of signal from vessels is accomplished by: You selected: B and C The correct answer for this question is: Spatial presaturation In an MRA sequence, the removal of signal from vessels is accomplished by spatial presaturation.

Shimming in MRI can be performed by all the following EXCEPT: You selected: Adding metal to different coils within the shim coil The correct answer for this question is: 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)

Gibbs truncation

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: You selected: Centric The correct answer for this question is: 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.

All of the following are true regarding gadolinium EXCEPT: You selected: Gadolinium chelates do pass a disrupted blood-brain barrier The correct answer for this question is: Gadolinium has six unpaired electrons Gadolinium has 7 unpaired electrons in its 4f orbitals giving it a very large magnetic moment.

The FDA approved oral contrast agent for MRI makes bowel appear: You selected: T1 hyperintense/ T2 hypointense The correct answer for this question is: T1 & T2 hypointense Perflubron, a type of perflorocarbon, has been used as a gastrointestinal MRI contrast agent for pediatric imaging, and works by reducing the amount of protons (as hydrogen) in a body cavity, thus causing it to appear dark in the images.

Contraindications for IV gadolinium contrast use are: You selected: All of the above The correct answer for this question is: None of the above There are no known contraindications to IV gadolinium contrast usage.

IV Gadolinium contrast administration is indicated for: You selected: MRA of the renal arteries The correct answer for this question is: Central nervous system IV Gadolinium contrast administration is indicated for the central nervous system, and for MRA of the lower extremities for AIOD, only.

Metastatic lesions enhance after injecting a gadolinium chelate because of: You selected: None of the above The correct answer for this question is: The breakdown in the blood brain barrier Metastatic lesions enhance after injecting a gadolinium chelate because of the breakdown in the blood brain barrier.

What is wrong with a T2 weighted, fast spin echo image that has a 1.1 second TR and an 90 millisecond TE? You selected: All of the above The correct answer for this question is: The TR does not sufficiently minimize the T1 weighted contrast The TR of 1100 ms is not long enough for T2 weighting

Which of the following parameter combinations would yield the most T1 weighting? You selected: 500 TR, 25 TE The correct answer for this question is: 350 TR, 15 TE

Column A in Image 108 corresponds to which MRI pulse sequence?

You selected: Proton density The correct answer for this question is: T2 weighted

Column A in Image 109 corresponds to which MRI pulse sequence?

You selected: T2 weighted with fat suppression The correct answer for this question is: T2 weightedLong TR and Long TE produce a T2 weighted image.

Column D in Image 111 corresponds to which MRI pulse sequence?

You selected: T2* gradient echo The correct answer for this question is: T2 FLAIR

Column D in Image 112 corresponds to which MRI pulse sequence?

You selected: T2* gradient echo The correct answer for this question is: T2 FLAIRLong TR + Long TE + Long TI = T2 FLAIR