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CT Cross Training > ASRT Exam 3 > Flashcards

ASRT Exam 3 Flashcards

1
Q

Which scanning method of the foot describes the scan plane parallel to the plantar surface of the foot?
A. Direct axial.
B. Direct oblique coronal.
C. Direct sagittal.
D. Oblique.

A

A - Direct axial.

Direct axial describes the scanning method when the gantry is parallel to the plantar surface of the foot. With the direct oblique coronal acquisition, the pts foot is flat on the table & the gantry is angled perpendicular to the subtalar joint.

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2
Q

In multislice CT, collimation is achieved using:

A

Beam and detector collimation.

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3
Q

If ROI measurements of the spleen are _________ or more than the liver, fatty infiltrates of the liver is indicated.

A

10 HU.

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4
Q

Which method of CT Cardiac Gating dramatically reduces pt dose?

A

Prospective method.

  • it acquires images in the lowest cardiac motion periods.
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5
Q

Retrospective method in Cardiac Gating

A

Acquires images during the whole cardiac cycle and then reconstructs only images from the desired phase of the cardiac cycle.

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6
Q

Oncology CT examinations of the thorax should extend through the:
A. Liver.
B. Spleen.
C. Diaphragm.
D. Adrenal Glands.

A

D - Adrenal Glands.

B/C adrenal glands are a common site for metastasis.

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7
Q

The psoas muscles are __________ to the lumbar spine.

A

Lateral.

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8
Q

Psoas muscles

A

Located lateral to the lumbar spine and originate on the transverse processes, boarders, & intervertebral discs of the lumbar vertebrae. They pass along the brim of the pelvis, entering the thigh to insert on the lesser trochanter.

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9
Q

Which kidney is located lower?

A

Right kidney because it is pushed down by the liver.

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10
Q

What phase are the kidneys routinely scanned in?

A

Nephrographic phase - where the cortex & medulla are in equilibrium, which BEST demonstrates parenchymal lesions.

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11
Q

What is the normal lab value range for a platelet count?

A

150,000 - 400,000 mm^3.

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12
Q

CTDIvolume is calculated as:

A

CTDIvolume = CTDIw / pitch.

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13
Q

What does GFR stand for?

A

Glomerular Filtration Rate.

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14
Q

What is GFR?

A

Glomelular filtration rate (GFR) is an approximation of the rate at which creating is filtered from the blood stream.

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15
Q

On the Hounsfield unit scale, pure water is assigned to:

A

0.

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16
Q

What is the HU unit for the following:
- Distilled water.
- Dense bone.
- Air.

A

Distilled water = 0.
Dense bone = 1000.
Air = -1000.

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17
Q

The Hounsfield unit of a substance is determined by:

A

The degree to which it attenuates the X-ray beam.

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18
Q

When using prospective gating to acquire images with minimal cardiac motion, imaging is triggered by the __________ of the ECG.

A

R wave

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19
Q

What is the typical kVp range for CT scanners?

A

80 kVp - 140 kVp.

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20
Q

A coronary artery calcium (CAC) scoring of 300 would be considered _________ on the Agatston scoring system.

A

Moderate.

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21
Q

The normal range for INR is:

A

0.8-1.2.

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22
Q

What factor is MOST important when considering using a power injection for a pediatric patient?
A. Patient’s weight.
B. IV gauge and location.
C. Amount of contrast.
D. Use of sedation.

A

B - IV Gauge and location.

Whenever using a power injection or hand injection.

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23
Q

__________ is a physical property of intravenous contrast media that describes its “thickness” or ability to flow.

A

Viscosity.

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24
Q

Temporal resolution can be improved with:
A. Increased scan speed.
B. Daily calibration.
C. Increased kVp.
D. Doubled mAs.

A

A - Increased scan speed.

Increasing the speed of the scan is one way to improve temporal resolution. A faster scan speed will reduce the amount of motion present during exposure. Gating is another approach to improve temporal resolution during cardiac studies.

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25
Q

A 25 cm Scan Field of View (SFOV) is considered:
A. Large.
B. Isometric.
C. Small.
D. Ipsilateral.

A

C - Small.

25 cm is a small SFOV compared to a 50 cm SFOV used for thoracic or abdomen examinations (large).

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26
Q

High frequency generates are used in CT scanners to;

A

Produce high voltage for the x-ray tube.

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27
Q

Where is the spleen located?

A

In the left hypochondriac region of the abdomen & appears to have the same attenuation as the liver on most routine CT abdominal scans.

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28
Q

Which of the following is NOT a risk factor for adverse reactions to IV contrast administration?
A. Asthma.
B. Allergy to shellfish.
C. Abnormal lab values (Cr. BUN, GFR).
D. Allergy to iodine.

A

B - Allergy to shellfish.

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29
Q

Which postprocessing techniques are routinely used for CT examinations of the cervical spine?
A. MPR.
B. MIP.
C. 3D.
D. All of the above.

A

D - All of the above.

MIP displays only the highest CT number values, 3D techniques for the spine and other body parts are used now that scanners can obtain Isotropic data sets. MPR generates CT images in different orientations.

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30
Q

Which lab value MOST accurately measures renal function?
A. BUN.
B. Creatinine.
C. GFR.
D. D-diner.

A

C - GFR.

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31
Q

The normal lab value range for creatinine is:

A

0.5 mg/dL - 1.5 mg/dL.

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32
Q

Which of the following devices is used to measure oxygen saturation in blood?
A. Pulse-oximeter.
B. Sphygmomanometer.
C. Electrocardiogram (ECG) machine.
D. Flow meter.

A

A - Pulse-oximeter.

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33
Q

The normal lab value for BUN is:

A

7 mg/dL - 25 mg/dL.

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34
Q

The device that allows the X-ray tube to rotate 360 degrees around the patient is the:

A

Slip-ring.

35
Q

Noncontrast abdomen pelvis CT examinations are most effective at evaluating:
A. Pancreatic abscesses.
B. Liver metastases.
C. Calcifications such as renal calculi.
D. Pulmonary embolisms.

A

C - Calcifications such as renal calculi.

36
Q

Compared to raw data, image data requires:
A. More storage space.
B. Less storage space.
C. The same amount of storage space.
D. Twice the storage space.

A

B - less the storage space.

Image data requires one-fifth the storage capacity compared to raw data. However, imaging data are more limited in how they can be manipulated & reconstructed.

37
Q

What happens to the image on the monitor when the DFOV is decreased?
A. The image size increases.
B. The image size decreases.
C. The image becomes clearer.
D. The image rotates.

A

A - the image size increases.

The DFOV allows the technologist to manipulate or target an area on the image to be displayed, and as the DFOV is decreased = the image size increases.

38
Q

As DFOV is decreased = the image size __________.

A

Increases.

39
Q

All of the following are patient positions for a CT exam of the wrist, EXCEPT:
A. Prone, wrist raised above the head.
B. Standing and resting wrist on the CT table.
C. Supine with wrist at the side.
D. Supine with wrist resting on the forehead.

A

D - Supine with wrist resting on the forehead.

Resting wrist on the forehead would produce scatter from the dense bone & increase dose to the patient.

40
Q

A CT abdomen pelvis exam should extend:

A

From above the diaphragm to below the symphysis pubis,

41
Q

To reduce radiation exposure during CT exams, the scanner uses:

A

Automatic tube current modulation (ATCM).

42
Q

The term for fatty infiltration of the liver is:
A. Isodense liver.
B. Steatosis.
C. Focal modular hyperplasia.
D. Hepatic cystitis.

A

B - Steatosis.

Steatosis or fatty liver infiltration results from hepatocytes becoming filled with cholesterol and triglycerides. This fat infiltration lowers the attenuation of the liver making it appear less dense than the spleen.

43
Q

Aliasing occurs due to:
A. Insufficient sampling.
B. Incorrect kernel selection.
C. Noise.
D. Incorrect matrix size.

A

A - Insufficient sampling.

44
Q

The starting point for a CT of the Adrenal Glands is:
A. 2 cm above the kidneys.
B. Right above the diaphragm.
C. Right below the diaphragm.
D. 2 cm below the kidneys.

A

B - Right above the diaphragm.

45
Q

The most common malignant primary tumor of the skeletal system is:
A. Chondroblastoma.
B. Osteochondroma.
C. Multiple myeloma.
D. Enchondroma.

A

C - Multiple Myeloma.

46
Q

Using raw scan data to create an image while scanning is called:
A. Prospective reconstruction.
B. Retrospective reconstruction.
C. Prospective interpolation.
D. Retrospective translation.

A

A - Prospective reconstruction.

Images producing using data during the scan are prospectively reconstructed. The same data can be used later to create images retrospectively after the scan is completed.

47
Q

What WW and WL setting would best display the lung fields of a thoracic CT exam?
A. WW1500; WL -600.
B. WW-1500; WL0.
C. WW350; WL50.
D. WW800; WL50.

A

A - WW1500; WL-600.

48
Q

Third generation CT scanners use _________ beam geometry.

A

Fan.

49
Q

A key focus of CT angiography of the brain is the:
A. Circle of Willis.
B. Bracheoscephalic artery.
C. Aorta.
D. Flax cerebra.

A

A - Circle of Willis.

50
Q

The MOST common CT detectors are:
A. Xenon gas detectors.
B. Solid state crystal detectors.
C. Helium gas detectors.
D. Solid state glass detectors.

A

B - Solid state crystal detectors.

Solid state crystal detectors are the standard for modern scanners, and are much more efficient than the xenon gas detectors used early in CT.

51
Q

Exposure is:
A. A measure of background radiation in humans.
B. A measure of absorbed dose in a specific area of human tissue.
C. A measure of effective dose in a specific mass of air by X-rays.
D. A measure of late effects of ionizing radiation on a specific volume of human tissue.

A

C - A measure of effective dose in a specific mass of air by x-rays.

52
Q

The scan delay after contrast administration is determined by:
A. The pts tolerance for IV contrast.
B. The time until the vessel reaches peak enchantment.
C. The time it takes the contrast to dissipate completely.
D. The protocol on the scanner.

A

B - the time until the vessel reaches peak enchacement.

53
Q

Which of the following CT exams is safe to perform on a pt with a serum creatine level of 2.8 mg/dL?
A. CTA of the lower extremity.
B. Brain perfusion.
C. Abdomen and pelvis without contrast.
D. CTV of the head.

A

C - abdomen and pelvis without contrast.

54
Q

Which Window width will optimally display soft tissue structures with varying densities, such as fat and muscle of the pelvis?
A. 50.
B. 150.
C. 400.
D. 1000.

A

C - 400.

55
Q

A rapid injection of IV contrast media is called:

A

A bolus injection.

56
Q

The pulmonary trunk branches into the __________________.

A

Right and left pulmonary arteries @ the level of the carina.

57
Q

The third-generation CT scanning method is best described as:
A. Translate-rotate using a pencil beam.
B. Stationary using a fan beam.
C. Rotate-stationary using a fan beam.
D. Constantly rotating using a fan beam.

A

D- Constantly rotating using a fan beam.

58
Q

In the digital acquisition system (DAS), the component that converts the electrical signals from the detectors into the data is the:

A

Analog to digital converter (ADS).

The DAS is responsible for measuring the transmitted beams absorbed by the detectors. The ADS is the component that converts analog signals from the detectors into digital data.

59
Q

What is the DAS (digital acquisition system) responsible for?

A

Responsible for measuring the transmitted beams absorbed by the detectors.

60
Q

Daily calibrations using a water phantom measure CT number __________ by placing a ROI at the iOS center of the image and comparing the CT number at additional predetermined locations around the image.

A

Uniformity.

61
Q

Slice thickness corresponds to which element of a voxel?
A. Width.
B. Depth.
C. Length.
D. Surface area.

A

B - Depth.

Slice thickness corresponds to the Z dimension & determines voxel depth.

62
Q

Which of the following is a parenteral route of medication administration?
A. Sublingual.
B. Subcutaneous.
C. Retrial.
D. Oral.

A

B - Subcutaneous.

Parental includes all routes OTHER THAN by mouth & alimentary canal.

63
Q

Parenteral Routes of medication

A

Parenteral administration includes all routes other than mouth & alimentary canal.
- examples of parental include: intramuscular, subcutaneous, intravenous, & intradermal injections.

64
Q

When wearing a sterile surgical gown, the sterile area includes:

A

The anterior chest area.

65
Q

High resolution CT thorax examinations are useful for evaluating all of the following disease processes EXCEPT:
A. Emphysema.
B. Cystic fibrosis.
C. COPD.
D. Pulmonary embolism.

A

D - Pulmonary embolism.

66
Q

Which of the following would be a normal set of vital signs for an adult?
A. Pulse - 89 BMP BP - 115/80.
B. Pulse - 102 BPM BP - 86/98.
C. Pulse - 55 BPM BP - 86/58.
D. All listed vital signs fall within normal ranges.

A

A - Pulse - 89 BPM BP - 115/80.

67
Q

In CT imaging, the z dimension corresponds to:

A

Slice thickness.

68
Q

In CT soft tissue examinations with IV contrast, the scan should be timed with:
A. Opacification of the arterial vessels.
B. Opacification of the venous vessels.
C. Opacification of the arterial & venous vessels, as well as mucosa and pathological tissue.
D. Opacification of the mucosa & pathologic tissue.

A

C - Opacification of the arterial & venous vessels, as well as mucosa and pathological tissue.

69
Q

The CT angiogram of the neck should range from:

A

The aortic arch to the skull base in the caudocranial direction.

70
Q

The prep for a CT Colonography includes:

A

Using a bowel cleansing agent, such as magnesium citrate and/or polyethylene glycol, the day before the exam.

71
Q

When using adult protocols on young children, the effective dose is _________ greater?

A

50%.

72
Q

The ____________ standard allows pt information to be transferred b/t the systems of different vendors.

A

Digital Imaging and Communications in Medicine (DICOM).

73
Q

In order to image the lumbar spinal cord with iodinated contrast, the contrast must be introduced:

A

Intrathecally.

74
Q

In a multislice spiral CT scanners, slice thickness is determined by:

A

Collimators just outside the tube & detector selection.

75
Q

Which of the following is NOT a function of the DAS?
A. Integrating signals from the detector array.
B. Converting the analog detector signals to digital data.
C. Transmitting the digital data to the computer.
D. Controlling the mA along the z axis of the scan.

A

D - Controlling the mA along the z axis of the scan.

76
Q

The two coronary arteries that originate on the aortic root are the:

A

Right coronary artery & the left main coronary artery.

77
Q

Which of the following algorithms has the highest spatial resolution?
A. Bone algorithm.
B. Soft tissue/standard algorithm.
C. Smooth algorithm.
D. Mediastinal algorithm

A

A - Bone algorithm.

78
Q

Following a CT myelogram, the pts head should be elevated _________ to reduce the chance of developing a severe headache.

A

30-degrees.

79
Q

For general studies of the thorax:
A. Contrast media is generally not needed b/c of the high inherent contrast of the anatomic structures.
B. Contrast media is generally always needed b/c of the low inherent contrast of the anatomic structures.
C. Contrast media is generally not needed b/c there is a low probability of disease processes being present in the thorax.
D. Contrast media is generally not needed b/c lung parenchyma does not enhance.

A

Answer: A.

80
Q

For a CT angiogram of the chest for pulmonary embolism, what flow rate should be used for IV contrast?

A

4-5 mL/sec.

81
Q

Iodinated contrast media for CT arthrography is introduced:

A

Intraarticulary.

82
Q

During back projection, __________ is/are projected onto the matrix.

A

Ray sum data.

The ray sum data consists of measurements of attenuation from each ray, and is projected onto the matrix during back projection.

83
Q

The modern method for a CT Brain sets the gantry parallel to the:

A

Supraorbitomeatal line.

84
Q

The portal venous phase of liver enhancement typically occurs __________ after IV contrast injection.

A

60-70 seconds.

In the portal venous phase of liver enhancement typically occurs 60-70 seconds after contrast injection, & is the phase that routine abdomen and pelvis CT examinations are obtained in.

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