CT Tutor Test 1 Wrong Answers Flashcards
Cone beam artifacts are related to the advances found in multi-row scanners because:
The traditional filtered back projection method of reconstruction cannot handle image formation with a beam collimation greater than 20mm
The system that consists of a secure network for transmission of patient information, a CT scanner, multiple workstations for interpreting and reviewing images and storage archived is called:
PACs
SFOV (or scan field of view) controls the diameter of the data acquired and is determined by
The detector array
The positioning system that assumes the patient is in the supine position is called:
Patient coordinate system
The technology that allowed the smaller, high-frequency generator to be located inside the CT gantry:
Slip ring technology
The main purpose of filtered backprojection is
To create artifact free images
What is the normal range for adult blood urea nitrogen (BUN) levels?
5-20 mg/dL
As the section (slice) width is increased the collimation is decreased.
True
False
True
Collimation determines slice width, the greater the collimation the smaller the slice width.
Lymphoma
Which of the following symptoms would be exhibited in a patient experiencing shock?
Rapid, shallow breath
Cyanosis
Tachycardia
All of the above
All of the above
Of the following x-ray interactions between the x-ray beam and the patient which results in the most patient dose?
Photoelectric effect
Bremsstrahlung
Compton scatter
Characteristic
Photoelectric effect
The photoelectric interaction results in the complete absorption of the energy from the incident x-ray photon within the patient’s body.
The type of image reconstruction used in the first-generation prototype CT scanner was _____________.
Convolution method
Fourier transform
Back-projection
Iterative technique
Iterative technique
With cupping artifacts, CT numbers are higher at the edges of the image and lower in the center.
True
False
true
There is less beam hardening at the edges of the image hence higher CT numbers and the radiation path are longer to the center of the image which causes a low number in the center.
Parotid gland
Submandibular gland
Sublingual gland
Salivary gland
Submandibular gland
If the filter at the aperture of the x-ray tube removed even more low energy x-ray photons which of the following would result?
An increase in partial volume artifacts.
A decrease in partial volume artifacts.
An increase in beam hardening artifacts.
A decrease in beam hardening artifacts.
A decrease in beam hardening artifacts.
Removing more of the low energy x-ray photons results in higher energy in the incident x-ray beam. This will decrease the amount of beam hardening artifacts due to the removal of the low energy x-ray photons.
When administering intravenous iodinated contrast media what type of infection control technique is required?
Surgical asepsis
Enteric precautions
Medical asepsis
Droplet isolation
Surgical asepsis
The average density of a solitary pulmonary nodule indicates it is benign when it falls within the following ranges…
15-30 Hounsfield units
50-80 Hounsfield units
125-145 Hounsfield units
175-200 Hounsfield units
175-200 Hounsfield units
Researchers feel pulmonary nodules appearing on CT examinations of the lungs can be considered benign if their average density is more than +164 Hounsfield units. The closer to +200 Hounsfield units the more certain the benign diagnosis is accurate.
Internal jugular vein
Internal carotid artery
External carotid artery
Common carotid artery
Common carotid artery
When completing a CT examination for the post-myelogram of the lumbar spine in an adult patient, which of the following would be an acceptable range for contrast volume for the intrathecal injection?
1-3 mL
5-9 mL
12-14 mL
18-22 mL
12-14 mL
The injection rate should not exceed approximately 17 mL in an adult patient, keeping the total dose of iodine below 3 grams. The most common range of injection during post-myelographic CT is 12-14 mL in an adult patient.
The acetabulum is formed by which of the following pelvic bones?
- Pubis
- Ischium
- Ilium
1, 2, and 3
The direction of the streaks that result from the edge gradient effect is perpendicular to the direction of the sharp density difference interface.
True
False
False
The edge gradient effect results from structures that have sharp edges and great density differences from neighboring tissues such as the interface of air and contrast media or bone and soft tissue. The resulting streak artifacts appear parallel to the direction of the sharp density difference interface due to the incorrect attenuation information that is collected and misinterpreted during the reconstruction process.
Aneurysm
Embolus
Thrombus
Abdominal neurogenic tumor
Thrombus
Transverse sinus
Sigmoid sinus
Straight sinus
Inferior sagittal sinus
Straight sinus
The normal range of respiratory rate in a child is…
20 to 30 breaths per minute
Of the following types of contrast material which may be used during a CT examination of the chest?
Iopamidol
barium sulfate
Diatrizoate meglumine
All of the above
All of the above
Lopamidol is a non-ionic contrast media. Diatrizoate meglumine is an ionic contrast media. Barium sulfate contrast in the form of a paste is used to outline the esophagus.
In reviewing a CT examination of a chest, the technologist notices a board or flat tabletop beneath the patient. This indicates what type of CT study?
Invasive
General survey
Radiation planning
Quantitative
Radiation planning
CT scans are used to localize an area of malignant pathology for radiation therapy treatment. During this type of CT scan, the patient must be positioned exactly the same as the position used during the radiation treatment.
The units of Sv and rem are used to measure
any kind of ionizing radiation
used to measure specifically x-ray radiation
rad and Gy
Of the following areas of the head, which commonly become calcified due to pathology and the aging process?
- Pineal gland
- Choroid plexus
- Thalamus
1 and 2 only
What is the primary reason iodine is the most common material used in radiopaque contrast media?
Viscosity
Radiolucency
Osmolality
High atomic number
High atomic number
A patient has a prior history of lymphoma. Of the following sets of slice widths and spacing, which would be best for a CT scan of the abdomen and pelvis?
3 x 3 mm
5 x 15 mm
10 x 15 mm
10 x 30 mm
10 x 15 mm
CT scans of the abdomen and pelvis may be performed with spacings of 15-20mm when using an aperture size of 10mm. If warranted, contiguous scans may be performed on specific areas of interest.
Ascending aorta
Left subclavian artery
Aortic arch
Aorta
Aortic arch
normal BUN
8-23 mg/dL.
Which of the following can be accurately demonstrated during a CT study of the abdomen without the use of iodinated contrast media?
- Appendicitis
- Renal stone
- Diverticulitis
- renal cyst
1, 2 and 3 only
Outpocketings of the wall of the colon are commonly associated with ____________.
Polyps
Intussusception
Diverticulitis
Diverticulosis
Diverticulosis
Diverticulosis causes the presence of small pouch-like openings in the colon wall. Diverticulitis is the inflammation of the diverticula.
A type of renal mass often seen in pediatric patients developing from immature kidney cells is termed…
von Hippel-Lindau disease
Wilm’s tumor
Krudenberg’s tumor
Ewing’s sarcoma
Wilm’s tumor
Once the x-ray beam passes through an object the intensity of the beam to a detector is called the…
Ray
Transmitted intensity
Incident intensity
Primary beam
Transmitted intensity
the amount of energy that passes through the patient onto a detector.
transmitted intensity
The term ____________ describes a contrast material that does not dissociate into charged particles within a solution.
Neutral
Non-ionic
Osmolar
Ionic
Non-ionic
What is the name of fibrous connective tissue that binds the kidneys in the retroperitoneum?
Fascia of Camper
Gerota’s fascia
Cooper’s ligament
Linea alba
Gerota’s fascia
Water-soluble based oral contrast (gastroview) should not be used when?
The patient has ascites
Hyoid bone
Thyroid gland
Epiglottis
Laryngeal vestibule
Epiglottis
What is adult normal respiration?
12-25 breaths per minute
The flow rate for a biphasic technique for a spiral CT study of the liver would include the which of the following sets?
2 mL/sec for 50 mL during the superior half of the liver
3 mL/sec for 50 mL followed by 1.5 mL/sec for 100 mL
2 mL/sec for 100 mL with scanning during both peak enhancement and the equilibrium phase
3 mL/sec for 150 mL with a 90 second delay before scanning
3 mL/sec for 50 mL followed by 1.5 mL/sec for 100 mL
A biphasic contrast injection of the liver should include a complete scan of the liver before the onset of equilibrium to avoid hepatic lesions from being obscured. A biphasic injection has a rapid initial flow rate followed by a slower injection rate.
Slice thickness is governed by the
smallest single detector element.
Stomach
Spleen
Liver
Pancreas
Stomach
What is an average scan delay on a portal-venous phase abdomen?
20-40 seconds
40-70 seconds
2-5 minutes
6-8 minutes
40-70 seconds
What is an average scan delay on a arterial phase abdomen?
20-40 seconds
40-70 seconds
2-5 minutes
6-8 minutes
20-40 seconds
What is an average scan delay on a equalibrium phase abdomen?
20-40 seconds
40-70 seconds
2-5 minutes
6-8 minutes
