CT REGISTRY REVIEW Flashcards

1
Q

The utilization of half-scan reconstruction can improve which of the following?
A. Uniformity.
B. Contrast resolution.
C. Temporal resolution.
D. Spatial resolution.

A

C. Temporal resolution.

Half-scan reconstruction consists of a reconstruction of data that was obtained from only a half of a gantry rotation. Utilization of this method allows for the scan time to be cut in half, and improves temporal resolution.

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2
Q

Which of the following is NOT a function of the RIS?
A. Store images.
B. Store orders.
C. Schedule patients.
D. Patient billing.

A

A. Store images.

RIS, or the radiology information system is used for scheduling patients, storing patient orders, patient billing, and start and end exam functions.

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3
Q

Which term is used to describe the rate that photons pass through an area in a set amount of time?
A. Effective kV.
B. Photon flux.
C. Effective mAs.
D. Photoelectric effect.

A

B. Photon flux.

Photon flux is the rate that photons that pass through an area, in a set of time. Increasing the rate of photons results in a decrease in noise. Increasing mA, kVp, or the scan time can also increase the photon flux within an image, but this comes at the cost of increased patient dose and decreased contrast resolution.

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4
Q

Which of the following is caused by an increase in the average energy of the x-ray beam?
A. Partial volume averaging.
B. Edge gradient
C. Beam hardening.
D. Streaks.

A

C. Beam hardening.

Beam hardening artifacts on an image are caused by the increase in the average energy of the x-ray beam.

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5
Q

Image compression that does NOT loose any data is known as:
A. Lossy.
B. Lossless.
C. DICOM.
D. CD-R.

A

B. Lossless.

Lossless data is compressed without any loss of data.

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6
Q

The name of the program that tests the performance of a CT scanner to ensure that it is performing at an optimal level and meeting standards is:

A

Quality Control.

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7
Q

Which of the following is a measure of the noise of an image?
A. ROI.
B. SSP.
C. Standard deviation.
D. HU.

A

C. Standard deviation.

Noise can be measured by observing the standard deviation of a given set of pixels within an ROI.

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8
Q

Which of the following is NOT true about 3D imaging?
A. They require the use of thick slices.
B. They provide the perception of depth.
C. They utilized overlapped images.
D. They require the use of thin slices.

A

A. They require the use of thick slices.

3D imaging requires thin, overlapped images to create a model that provides the perception of depth.

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9
Q

Which of the following provides optimal imaging of distal upper extremities?
A. Arms by their side in the neutral position.
B. Arms by their side in the pronated position.
C. Arm not of interest removed from the scan field.
D. Arm of interest in the “superman” position.

A

D. Arm of interest in the “superman” position.

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10
Q

The volume of a voxel is impacted by adjustments to all of the following except:
A. Matrix size.
B. DFOV.
C. Slice thickness.
D. MPR.

A

D. MPR.

The DFOV, matrix, and slice thickness all impact the volume of voxel.

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11
Q

Of the following, which is a non ionic radiopaque contrast media?
A. Iopamidol.
B. Iodipamide.
C. Iothalamate.
D. Diatrizoate.

A

A. Iopamidol.

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12
Q

A CT image has a WL of 0 and a width of 300. Which of the following is correct?
A. The CT numbers will range between 0 and 300.
B. The CT numbers will range between 100 and 400.
C. The CT numbers will range between -300 and 0.
D. The CT numbers will range between -150 and +150.

A

Answer: D

The range of the numbers is referred to as the Window Width and the center of the range is the Window Level.

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13
Q

At which vertebral level does the spinal cord end?

A

L1-L2.

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14
Q

Which of the following completes the majority of the processing of the image?
A. Array processor.
B. DAS.
C. ADC.
D. Detectors.

A

A. Array processor.

The array processor completes the majority of the processing of the image.

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15
Q

Hypertrophy of the facet of the vertebrae is known as:

A

Spondylosis.

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16
Q

The MinIP is used to display:

A

The minimum attenuation within a voxel.

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17
Q

A low level of oxygen in the blood is called:

A

Hypoxemia.

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18
Q

Conversion of data into digital values is completed by the:
A. DICOM.
B. ADC.
C. DAS.
D. Array processor.

A

B. ADC.

The ADC converts the data into digital values, which determine the grayscale resolution

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19
Q

A contiguous data set means that:

A

There is no gap in the image data set.

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20
Q

Images for a CT Orbit exam should be aquired:
A. Parallel to the infraorbital meatal line.
B. Superior to the infraobital meatal line.
C. Perpendicular to the infraobital meatal line.
D. Inferior to the infraobital meatal line.

A

A. Parallel to the infraobital meatal line.

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21
Q

CTDI measures:

A

The dose received in a single section or slice.

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22
Q

Which of the following may require a pt to be at full expiration during image acquisition?
A. CT Chest high Resolution.
B. CTA Chest.
C. CT Pulmonary Angiography.
D. CT Chest.

A

A. CT Chest high resolution.

During the CT Chest High Resolution exam, imaging is acquired while the patient is holding their breath in both inspiration and expiration.

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23
Q

Which of the following is true about CT Lung Nodule?
A. It is performed with held expiration.
B. It is performed with slow, steady breathing.
C. It is performed with an increased technique.
D. It is performed with a reduced technique.

A

D. It is performed with a reduced technique.

CT lung nodule protocols are often performed with decreased kV and mA settings to lower the patient’s dose. The settings are based upon the patient’s weight and produce a somewhat limited study.

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24
Q

Which of the following may result in mis-registration of pt info?
A. Motion.
B. Partial volume averaging.
C. Tube arcing.
D. Cupping.

A

A. Motion.

Patient motion on the image appears as streaks, misregistration of information, blurring, or step artifact.

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24
Q

The accuracy of the CT number compared to the linear attenuation coefficient is:
A. Linearity.
B. Quantum mottle.
C. Uniformity.
D. Noise.

A

A. Linearity.

Linearity describes the accuracy of a CT number compared to the linear attenuation coefficient of the object that was imaged.

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25
Q

When calculating DLP, what relationship does scan length have with dose?
A. It does not play a role.
B. It is proportional.
C. It is disproportionate.

A

B. It is proportional.

DLP is the total amount of exposure for an exam, with consideration of the scan length. The scan length is proportional the radiation dose

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26
Q

Which of the following is NOT a parenteral route for medication administration?
A. Sublingual.
B. Subcutaneous.
C. Intramuscular.
D. Intrathecal.

A

A. Sublinqual.

Iodinated contrast media are most often injected directly into the blood intravenously for CT exams. This is considered a parenteral administration of contrast. Parenteral administration is any non oral method of administration.

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27
Q

Which imaging plane is parallel to the metatarsals of the foot?
A. Sagittal.
B. Coronal.
C. Direct axial.
D. Oblique axial.

A

D. Oblique axial.

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28
Q

Which process uses the entire data set for image reconstruction?
A. MPR.
B. Surface rendering.
C. Volume rendering.
D. MinIP.

A

C. Surface Rendering.

Volume Rendering uses the entire data set for image reconstruction. Because the entire data set is used, volume rendering creates a higher quality image.

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29
Q

During a CT Urinary Tract exam, pts may be imaged in the prone position to better:

A

Differentiate stones within the urinary tract.

When performing a CT Urinary Tract exam it may be necessary to complete an additional acquisition with the patient in the prone position which helps to differentiate stones within the urinary tract.

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30
Q

When possible, which of the following should be avoided during pediatric imaging?
A. Reduced kV.
B. Multiphase imaging.
C. Scanning only the area of interest.
D. Validation of clinical appropriateness.

A

B. Multiphase imaging.

t is important that the radiation dose for each pediatric patent is optimized so that the overall dose is minimized. Several steps that can be taken to reduce the overall dose include eliminating multiphase imaging, reducing kV and mA, and ensuring clinical appropriateness.

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31
Q

Which of the following phases contrast enhancement best demonstrates the renal pelvis?
A. Early arterial.
B. Late arterial.
C. Excretory.
D. Corticomedullary.

A

C. Excretory.

Excretory phase of enhancement occurs at least 3 minutes post administration of IV contrast. This phase is ideal for imaging the renal pelvis, ureters, and bladder.

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32
Q

When performing a CT Head exam, the gantry should be angled:

A

Parallel to the infraorbital meatal line.

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33
Q

Voxels that form a perfect cube are referred to as:
A. Anistoropic.
B. Isotropic.
C. MPR.
D. Pixel.

A

B. Isotropic.

Isotropic imaging refers to when the length, width, and height of a voxel are equal and form a perfect cube. Isotropic imaging results in images with excellent quality.

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34
Q

The x-ray beam utilized in MDCT is known as:
A. Electronic beam.
B. Cone beam.
C. Fan beam.
D. Pencil beam.

A

B. Cone beam.

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35
Q

The generator for the CT scanner is located in the:

A

Gantry

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36
Q

Which of the following is NOT part of the Circle of Willis?
A. Right & left anterior cerebral arteries.
B. Anterior communicating artery.
C. Right and left internal carotid arteries.
D. Right and left vertebral arteries.

A

D. Right and left vertebral arteries.

The Circle of Willis consist of right and left anterior cerebral arteries, anterior communicating artery, right and left internal carotid arteries, right and left posterior cerebral arteries, and right and left posterior communicating arteries

37
Q

Which of the following is NOT required to be included in the structured dose report?
A. Pitch.
B. DFOV.
C. mA.
D. kV.

A

B. DFOV.

The structured dose report will typically contain information used during the examination such as kV, mA, SFOV, pitch, detector collimation, and scan length.

38
Q

The early arterial phase of contrast enhancement of the liver occurs at:

A

15-20 seconds.

the early arterial phase of enhancement of the liver occurs 15-20 seconds post administration of contrast media. This is the optimal phase for arterial imaging of the liver, as the liver parenchyma is minimally enhanced.

39
Q

Transmission of data to the computer is completed by the:

A

DAS.

The DAS transmits the data to the computer.

40
Q

Which of the following does NOT affect contrast resolution?
A. Noise.
B. Detector size.
C. Object contrast.
D. Gantry rotation.

A

D. Gantry rotation.

Gantry rotation affects temporal resolution.

41
Q

Which system allows for large amounts of exams to be electronically stored & readily available for radiologist?

A

PACS.

Images are transferred to a Picture Archival and Communication System (PACS) for long-term storage. PACS system allow for large amounts of exams to be electronically stored and readily available for the radiologist.

42
Q

GFR may be affected by: (Select all that apply)
1. Race.
2. Sex.
3. Age.

A

1, 2, and 3.

To calculate GFR the following is needed: Patient’s measured serum creatinine level, patient’s age, sex, and race

43
Q

The term used to describe a filtration algorithm that removes blurring in an imaging during back-projection is:
A. Convolution.
B. Interpolation.
C. Iterative reconstruction.
D. MPR.

A

A. Convolution.

Convolution is filtration algorithm that removes blurring in an image during back-projection.

44
Q

Which of the following is measured in milligray?
A. Effective dose.
B. Absorbed dose.
C. Exposure.
D. Curie.

A

B. Absorbed dose.

45
Q

Which of the following is most likely to be injured from blunt trauma?
A. Kidney.
B. Spleen.
C. Liver.
D. Gallbladder.

A

B. Spleen.

46
Q

Drowsiness is most commonly associated with which of the following?
A. Lethargy.
B. Insomnia.
C. Coma.
D. Shock.

A

A. Lethargy.

If a patient is experiencing lethargy, the patient seems drowsy, but is able to aroused.

47
Q

Which of the following takes into consideration the variations in density of the object being imaged?
A. CTDI.
B. CTDI 100.
C. CTDI vol.
D. CTDI W.

A

D. CTDI W.

CTDIW accounts for the variations in the density of an object being imaged. CTDIW is calculated by summing the exposure recorded at the periphery of the field, with the exposure at the centrally of the field.

48
Q

The mathematical process that uses data points above & below a slice to reconstruct an image is known as:

A

Interpolation.

Interpolation is used in helical CT scans and is a mathematical process that uses data points above and below a slice to reconstruct an image.

49
Q

Which of the following is measured by placing several ROIs throughout an image of a water phantom?
A. Linearity.
B. Uniformity.
C. Contrast resolution.
D. Noise.

A

B. Uniformity.

Uniformity is measured with the use of a uniform water phantom. This takes place by imaging the phantom and placing several ROIs throughout the phantom on the CT image.

50
Q

Which two metrics are most commonly displayed in CT dose reports? (Select all that apply)
1. CTDI.
2. DLP.
3. Absorbed dose.
4. Exposure.

A

1 and 2 only.

Typically, there are two metrics that are displayed in structured dose reports that quantify the patient’s radiation dose for that particular exam. These include CT Dose Index (CTDI) and Dose-Length Product (DLP)

51
Q

The number of data channels active & the effective section thickness is known as:
A. Detector electronic.
B. Detector element.
C. Detector configuration.
D. Detector geometry.

A

C. Detector configuration.

Detector configuration describes the number of data channels active and the effective section thickness.

52
Q

Post-patient collimation occurs:

A

After the beam passes through the pt, but BEFORE striking the detectors.

53
Q

Detectors that contain channels that are equal in all directions are known as:
A. Hybridarray.
B. Uniform matrix array.
C. Complex array.
D. Adaptive array.

A

B. Uniform matrix array.

Uniform matrix array detectors contain channels that are equal in all dimensions.

54
Q

Which of the following artifacts may be resolved through the calibration of the CT scanner?
A. Ring.
B. Streak.
C. Out of field.
D. Tube arcing.

A

A. Ring.

Calibration of the CT scanner can help to overcome ring artifacts. If that doesn’t work, service may need to be called.

55
Q

Which of the following is NOT a high-osmolar contrast media?
A. Iothalamate.
B. Metrizoate.
C. Diatrizoate.
D. Iohexol.

A

D. Iohexol.

56
Q

During a routine CT abdomen and pelvis exam, imaging is typically acquired during which phase of venous enhancement?
A. Portal venous.
B. Arterial.
C. Equilibrium.
D. Delay.

A

A. Portal venous.

Imaging for a routine CT Abdomen and Pelvis exam typically acquired during the portal venous phase of contrast enhancement.

57
Q

In a CT Head exam thin slices to reduce beam hardening are utilized:
A. from the vertex through the skull base.
B. From the skull base through the posterior fossa.
C. From the posterior fossa through the vertex.
D. Thin sections are not required.

A

B. from the skull base through the posterior fossa.

In a CT Head exam thin sections (2-5mm) are utilized to reduce beam hardening ratification and will go from the skull base through the posterior fossa.

58
Q

Which of the following is a measure of the quantity of blood contained within 100g of brain tissue?
A. Mean transit time.
B. Cerebral blood volume
C. Cerebral blood flow.

A

B. Cerebral blood volume.

59
Q

The appropriate slice thickness for a CT Neck (Larynx) exam is:
A. 0.5 mm
B. 1-2 mm.
C. 5 mm.
D. 3-4 mm.

A

B. 1-2 mm.

60
Q

The typical delay for a CT Adrenal Gland exam would be:
A. 10-15 minutes.
B. 7-9 minutes.
C. 3-5 minutes.
D. 60 seconds.

A

A. 10-15 minutes.

61
Q

Which of the following is NOT found in the midfoot?
A. Talus.
B. Navicular.
C. Cuneiform.
D. Cuboid.

A

A. Talus.

The bones of the midfoot include the navicular, cuboid, and cuneiform bones.

62
Q

The liver receives 75% of its blood from the portal vein and 25% from the:
A. Splenic vein.
B. Portal artery.
C. Inferior vena cava.
D. Hepatic artery.

A

D. Hepatic artery.

The liver is unique in that it has a dual blood supply. The majority of the blood that supplies the liver comes from the portal vein (75%), and the rest comes from the hepatic artery (25%).

63
Q

Of the following, which would be most appropriate to use with a power injector?
A. Angiocatheter.
B. Butterfly needle.
C. Spinal needle.
D. Foley catheter.

A

A. Angiocatheter.

IV administration of iodinated contrast typically takes place through an angiocatheter, most often 18-22 gauge because they are rated for use with power injectors.

64
Q

CT PET is utilized to measure the uptake of:
A. Glucose.
B. Contrast media.
C. FDG.
D. B-Blockers.

A

C. FDG.

Positron emission tomography utilizes the fludeoxyglucose F 18 (FDG) radiopharmaceutical to measure the amount of uptake of FDG by the body’s cells.

65
Q

Which of the following is NOT included in the mediastinum?
A. Trachea.
B. Superior vena cava.
C. Thyroid gland.
D. Thymus.

A

C. Thyroid gland.

66
Q

The amount of calcification in the coronary arteries is classified by the:
A. Volume rendering.
B. CT number.
C. Standard deviation.
D. Agatston score.

A

D. Agaston score.

In a CT Cardiac Calcium Score, the coronary arteries are assessed for calcifications using the Agatston scoring system.

67
Q

During a CT Neck (Soft Tissue) exam, the gantry should be angled in which direction to avoid streak artifacts between the orbits and the hard palate from the patient?

A

A. Parallel to the hard palate.

68
Q

In order to obtain sufficient iodine opacification during a CT examination, which of the following concentrations must be present?
A. 2-8 mg/mL.
B. 10-20 mg/mL.
C. 30-40 mg/mL.
D. 75-100 mg/mL.

A

A. 2-8 mg/mL.

In order to obtain sufficient iodine opacification during a CT examination there must be 2-8 mg/mL of iodine in the patient’s bloodstream.

69
Q

Inflammation, thickened wall, and appendicolith may indicate:

A

Appendicitis.

Appendicitis presents as an inflamed and thickened appendix wall. Presence of an appendicolith may also indicate appendicitis.

70
Q

Which of the following is most likely to be used during a CT Enterography exam?
A. Positive oral contrast.
B. Negative oral contrast.
C. Neutral oral contrast.
D. No oral contrast is used.

A

C. Neutral oral contrast.

During CT Enterography a neutral oral contrast agent may be used to opacify the small bowel. Neutral contrast agents work by distending the GI tract, while allowing for clear visualization of the bowel wall.

71
Q

Spatial resolution within the x and y direction is known as:
A. In-plane resolution.
B. Out of plane resolution.
C. Spatial frequency.
D. Longitudinal resolution.

A

A. In-plane resolution.

In-plane resolution is the spatial resolution within the x and y directions.

71
Q

Damage that occurs to the pars interarticular is known as:

A

Spondylolysis.

72
Q

Which of the following describes the artifact that arises as the beam becomes harder in the center of an image than it does at the edge?
A. Cupping.
B. Streaking.
C. Beam hardening.
D. Cone beam.

A

A. Cupping.

Cupping artifacts arise in an image when the beam becomes harder in the center of the object being imaged, than it does at the edge. This artifact commonly occurs in the CT Head exam.

73
Q

Grouping together detector channels to form a section width is known as:
A. Detector configuration.
B. Binning.
C. Detector collimation.
D. Slice thickness.

A

B. Binning.

Binning is the term used to describe grouping together detector channels to form a section width.

74
Q

The mathematical process used to create an image in which attenuation data are projected onto a matrix is known as:
A. Back projection.
B. Filtered back projection.
C. Iteration.
D. Fourier reconstruction.

A

A. Back projection.

Back Projection is a mathematical process used to create image in which attenuation data are projected onto a matrix.

75
Q

The use of a high resolution algorithm will result in which of the following?
A. An image with decreased spatial resolution.
B. An image with increased noise.
C. An image with decreased noise.
D. An image with increased spatial resolution.

A

B. An image with increased noise.

The use of reconstruction algorithms that require high resolution, result in an image with increased noise.

76
Q

Which of the following connects the small intestines to the large intestine?
A. Pyloric sphincter.
B. Ileocecal valve.
C. Duodenal bulb.
D. Cecum.

A

B. Ileocecal valve.

77
Q

Which of the following terms is NOT an indication for imaging of the renal arteries?
A. Stenosis.
B. Cysts.
C. Kidney Transplant.
D. Aneurysms.

A

B. Cysts.

Renal arteries may be imaged for stenosis, aneurysms, or to evaluate candidacy for kidney transplant.

78
Q

How are CT numbers generated?

A

Comparing the attenuation of the tissues imaged to the attenuation of water.

79
Q

Imaging of a hemangioma should take place during which phase of contrast enchancement?
A. Delay.
B. Early arterial.
C. Portal venous.
D. Equilibrium.

A

A. Delay.

The delay phase of contrast enhancement occurs 5 to 15 minutes post administration of contrast media. Imaging during this phase is utilized to show a hemangioma becoming isodense with the surrounding tissues.

80
Q

The outer portion of the intervertebral disc is known as:

A

Annulus fibrosus.

81
Q

The total amount of exposure with consideration of the can length is known as:

A

DLP.

DLP is the total amount of exposure for an exam, with consideration of the scan length. The scan length is proportional the radiation dose.

82
Q

Which of the following measures radiation dose obtained during helical scanning & accounts for dose in the x,y, and z axis?
A. Effective dose.
B. Absorbed dose.
C. CTDI100.
D. CTDIVol.

A

D. CTDIVol.

CTDIVol measures the radiation dose obtained during a helical scan and accounts for dose in the x, y, and z axis.

83
Q

What describes the Shape of the xray beam as it leaves the tube housing?

A

Beam Geometry

84
Q

The electronic signal emitted by the CT detector is:

A

Is equal to the radiation transmitted to the detector.

85
Q

The persistence of the xray event after the radiation has been shut off is known as;

A

Afterglow

86
Q

A CT detector that is unable to differentiate between similar transmission measurements would have :

A

Low dynamic range.

87
Q

In scintillating detectors, the crystal emits a light that is:

A

Is equal to the xray that it encounters

88
Q

In regards to adaptive arrays, what is its relationship to slice thickness?

A

Only the inner half of the two detectors can be exposed to adjust slice thickness smaller than an individual element.

89
Q

Which of the following is located between the detectors and the computer?
A. slip rings.
B. gantry.
C. DAS.
D. x-ray tube.

A

C. DAS.

The Data Acquisition System is located between the detectors and the computer, and performs three major functions.

90
Q

Transmission measurement data is changed into attenuation & thickness data through a process called:

A

Logarithmic conversion.