ASRT Exam 4 Flashcards
The CT detectors, rapid signal decay means that the detector is:
Able to quickly measure transmitted X-ray photons with limited afterglow.
Rapid signal decay allows CT detectors to what?
They allow to quickly measure transmitted X-ray photons with an insignificant amount of afterglow. The rapid signal decay enables the detector array to have an efficient response time & adequate recovery before subsequent measurements are taken.
To improve visualization of intramural structures on a CT scan of the spine after a myelogram:
A. Roll the patient once or twice before scanning to mix settled contrast.
B. Administer IV contrast with an injection rate of 5-7 mL/s.
C. Delay the follow-up CT scan for 8 hours after injection of contrast material.
D. Patient should ingest barium sulfate 30 minutes before the scan.
A - roll the pt once or twice before scanning to mix settled contrast.
Which of the following is located within the mediastinum?
A. Descending aorta.
B. Inferior fissure.
C. Lung apices.
D. Parenchyma.
A - Descending aorta.
What organs are located within the mediastinum?
Descending aorta, thymus gland, trachea, esophagus, heart, and great vessels.
Which of the following is true for a multi-physic CT scan of the abdomen to evaluate the pancreas?
A. IV contrast is injected at 1 mL/sec.
B. The study is completed without contrast.
C. Thick slices with gaps are used for post-processed images such as MPR and 3-D images.
D. Scans are completed in the late arterial & portal venous phases.
D - Scans are completed in the late arterial & portal venous phases.
What is a common to use to evaluate for possible stones in the pancreas?
3 to 5 mL/s injection rate or occasionally a noncontrast study.
What kind of post-processing should be used for the pancreas?
3-D or MPR, thin, overlapping slices.
__________ is a physical property of IV contrast media defined as the number of particles per unit of liquid.
Osmolality.
A __________ high-resolution CT (HCRT) of the chest is optimal for evaluating interstitial lung disease involving dependent areas of the lung (such as asbestosis).
Prone inspiration.
The prone position of an HRCT of the lung is optimal for evaluating pathology such as asbestosis, as it can differentiate abnormalities in the dependent portions of the lung.
A CT scan of the temporal bone and internal auditory canal (IAC) for suspected fracture uses all of the following, EXCEPT:
A. Thin slices.
B. A small DFOV.
C. Intravenous contrast media.
D. A bone algorithm
C - Intravenous contrast media.
What imaging plane is parallel to the foot’s plantar surface?
A. Direct axial.
B. Oblique axial.
C. Coronal.
D. Sagittal.
A - Direct axial.
__________ has an Osmolality equal to that of blood.
Isomolar contrast media.
The adrenal glands are part of the __________ system.
Endocrine.
In a single-slice CT scanner, pre-patient collimation is used to:
A. Remove the low energy X-rays from the beam.
B. Harden the X-ray beam.
C. Ensure the X-ray beam is the proper width.
D. Increase the amount of scatter radiation that hits the detectors.
C - Ensure the X-ray beam is the proper width.
In a single-slice CT scanner, pre-patient collimation is used to ensure the X-ray beam is at the proper __________.
WIDTH.
The display field of view (DFOV) for a CT series can be changed by using:
A. Reconstructed data.
B. Raw data.
C. Image data.
D. Multiplanar reformation.
C - Image Data.
In a CT examination of the spinal cord with contrast enhancement, the contrast is introduced in the:
Subarachnoid space.
Which pulse is measured behind the patients knee?
Popliteal pulse.
The forward slipping of an upper vertebral body over the lower is called __________, and is commonly caused by degenerative changes.
Spondylolisthesis.
CT image quality is evaluated in terms of:
Spatial resolution and contrast resolution.
It is very important for a CT scanner to be able to differentiate small, high contrast objects, which defines its spatial resolution. Equally important is the contrast resolution, which is the ability of the scanner to differentiate between objects with similar densities compared to their background.
Which of the following CT studies would require informed consent from the pt?
A. Noncontrast brain scan.
B. High-resolution chest CT.
C. CT of the lower extremity.
D. CT guided abscess drainage.
D - CT guided abscess drainage.
The annual whole body dose limit for radiation workers is:
50 mSv per year.
For a Ct of the thoracic spine, which of the following is a typical display field of view (DFOV)?
A. 15 cm.
B. 25 cm.
C. 35 cm.
D. 44 cm.
A - 15 cm.
15 cm (possibly down to 10 cm), is a typical DFOV for the t spine.
What radiation dose measurement uses weighted factors to account for tissue radio sensitivity?
A. Effective dose.
B. Air Kerma.
C. Absorbed dose.
D. Equivalent dose.
A - Effective dose.
Different tissues & organs in the body have various levels of radio sensitivity. The effective dose uses a tissue weighting factor to account for these differences, and is measured in Sv or rem.
Effective Dose
Different tissues & organs in the body have various levels of radio sensitivity. The effective dose uses a tissue weighting factor to account for these differences, and is measured in Sv or rem.
The falciform ligament extends from the liver to the:
Anterior abdominal wall & diaphragm.
A blood pressure of 160/110 mm Hg indicates:
Hypertension.
The Osmolality of iodinated contrast media refers to the:
Number of miliosmoles per kilogram of water.
The amount of blood (in mL) that moves through 100g of brain tissue each minute is the:
Cerebral blood flow (CBF).
What is the normal range for Cerebral blood flow (CBF)?
50 to 60 mL/100g/min.
Which of the following can be used to relax the smooth muscles of arteries & veins to treat the sudden onset of angina pain?
A. Nitroglycerin.
B. Epinephrine.
C. Atropine.
D. Diazepam.
A - Nitroglycerin.
What is the typical scan range for a CT soft tissue neck with contrast to evaluate for swollen glands?
From the superior orbital rim through the lung apices.
All of the following are typical post-processing images created during a CTA carotids exam, EXCEPT:
A. Sagittal Multiplanar reconstruction (MPR).
B. Minimum intensity projection (minIP).
C. Volume rendering.
D. Coronal Multiplanar reconstruction (MPR).
B - Minimum intensity projection (minIP).
That type of post-processed image displays the MINIMUM PIXEL VALUES and is more useful for evaluating anatomy such as the lung, trachea, or biliary tree.
Which of the following body types will require the highest radiographic technique for imaging?
A. Sthenic.
B. Hyposthenic.
C. Asthenic.
D. Hypersthenic.
D - Hypersthneic.
Hyper = large patient and will require more radiographic exposure.
With all other factors remaining constant, which of the following would decrease a patients radiation dose during a helical CT examination?
A. Increasing mAs.
B. Decreasing source-detector distance.
C. Increasing pitch.
D. Decreasing DFOV.
C - Increasing Pitch.
Increasing pitch = table moves faster through gantry = less time = less radiation.
Which of the following CT brain examinations would be the most suitable to evaluate the circle of Willis?
A. CT without contrast.
B. Brain perfusion.
C. CT venography (CTV).
D. CT angiography (CTA).
D - CT angiography (CTA).