CT PROTOCOLS FINAL EXAM
QUESTIONS WITH COMPLETE
ANSWERS
localizer scan - Answer-his scan allows the technologist to prescribe the location of
cross sectional slices. The extent of the anatomic area included on localizer images is
controlled by the technologist and dependent on the type of study.
collimation - Answer-In MDCT this parameter is controlled by detector configuration and
affects -Total scan time -Thinnest available recons -Noise / Low contrast resolution -
Affect quality of coronals and other reformats
kVp - Answer-this parameter determines tube potential
gantry rotation speed - Answer-the technical parameter controlling a CT system of
temporal resolution. It is how fast the gantry rotates and how fast the images are taken.
pitch - Answer-described as the movement of the table throughout a helical scan
divided by slice thickness
reconstructed slice thickness - Answer-performed after the initial prospective
reconstruction to slice thickness
slice interval - Answer-the distance between the center of one CT section and the
center of the next adjacent section
bolus phase - Answer-In this phase, the arterial structures are filled with contrast and
brightly displayed on the image. Contrast has not yet filled the venous structures. Also
called the arterial phase.
non-equilibrium phase - Answer-In this phase the contrast is still brighter in the arteries
than in the parenchyma of organs, but now the venous structures are also opacified,
This phase begins 1 minute after the start of the injection and lasts only a short time.
Also called the venous phase.
equilibrium phase - Answer-In this phase the contrast is largely emptied from the
arteries, is greatly diluted in the veins and has soaked the organ parenchyma. Also
called the delayed phase.
CVAD - Answer-venous catheter designed to deliver medications and fluids directly into
the superior vena cava, inferior vena cava, or right atrium
,PICC - Answer-long catheter that is inserted through the large veins of the upper arm
and advanced so that its tip is located in the lower one third of the SVC
Tunneled catheters - Answer-inserted into the targeted vein (often the subclavian)
underneath the skin, i.e., Hickman, Broviac, and Groshong
Non-tunneled catheters - Answer-larger caliber devic than PICC, inserted into a
relatively large, more central vein such as the jugular, subclavian or (less commonly)
the femoral vein
Tumors and other disease processes always have different attenuation coefficients than
those of their surrounding tissue. - Answer-False
For a patient's consent to be valid, she must be considered competent to make the
decision at hand and her consent must be voluntary. - Answer-True
In communication, you should assume that a nonresponsive patient cannot hear you. -
Answer-False
Communication is the transmission of meaning. - Answer-True
What qualities must the CT technologist look for in an established IV site when
administering IV contrast?
Please choose all that apply. - Answer--ensure that the line is patent
-evaluate the site for appropriateness for contrast media injection
-turn off existing medication, if OK's by nurse or physician
-ensure that IV gauge is appropriate for contrast media protocol
Conventional radiography barium suspension cannot be used in CT. - Answer-True
A number of independent studies have established a link between effective
communication and a reduction in malpractice claims. - Answer-True
Because the data selected for SFOV are a subset of all the scan data available, the
SFOV cannot be larger than the DFOV. - Answer-False
The half life of IV contrast for patients with normal renal function is 4 hours. - Answer-
False
In general the shortest gantry revolution time ( such as 0.4-0.5) must be used for most
CT studies. An exception to this rule is CT evaluation of a large patient, where use of
longer gantry rotation time helps increase total tube current. - Answer-True
Which is NOT a goal of the questions included on the CT history? - Answer--choosing
the most intelligent technologist
, -choosing the proper radiologist
What barrier to communication is likely to occur when the receiver doesn't like portions
of the sender's message? - Answer-receiver distortion
Which is true about meanings with respect to communication? - Answer-meanings are
not entirely contained in the message. They are interpreted by the message receiver.
Which method of contrast administration is programmable for uniphasic, biphasic and
triphasic injections? - Answer-mechanical or power injection
Which factors that affect the degree of contrast enhancement in human tissue are
controllable by the technologist? - Answer-pharmokinectics
Which of the following would be considered high risk for CIN? - Answer-patient with
diabetes mellitus and pre-existing renal insufficiency
Comparing the reported rate of adverse reaction: - Answer-LOCM are much lower than
HOCM by a factor of approximately4 to 5 times
Contrast reactions that are accompanied by a temporary drop in blood pressure,
bronchospasm, facial edema, urticaria, and laryngeal edema are generally classified as:
- Answer-moderate reactions
Which factors affect viscosity of an intravenous iodinated contrast agent?
1. iodine concentration
2. lipid solubility
3. total volume delivered
4. temperature of the agent - Answer-1 & 4
A contrast material that is of substantial higher density than that of the surrounding
structures can be referred to as a ___________ agent. - Answer-positive
When does contrast enhancement typically reach a near-peak in the aorta? - Answer-
From 15 to 22 seconds after the start of the injection
Which is the preferred venous access site when a mechanical injector is used? -
Answer-antecubital or large forearm vein
For what flow rate is a 20-gauge or larger catheter preferable? - Answer-2-4 mL/kg
By how many Hounsfield units must two tissues differ to be visibly different on a CT
scan? - Answer-at least 10 HU
Which should not be used for verifying a patient's identity? - Answer-The name posted
above the patient's bed
QUESTIONS WITH COMPLETE
ANSWERS
localizer scan - Answer-his scan allows the technologist to prescribe the location of
cross sectional slices. The extent of the anatomic area included on localizer images is
controlled by the technologist and dependent on the type of study.
collimation - Answer-In MDCT this parameter is controlled by detector configuration and
affects -Total scan time -Thinnest available recons -Noise / Low contrast resolution -
Affect quality of coronals and other reformats
kVp - Answer-this parameter determines tube potential
gantry rotation speed - Answer-the technical parameter controlling a CT system of
temporal resolution. It is how fast the gantry rotates and how fast the images are taken.
pitch - Answer-described as the movement of the table throughout a helical scan
divided by slice thickness
reconstructed slice thickness - Answer-performed after the initial prospective
reconstruction to slice thickness
slice interval - Answer-the distance between the center of one CT section and the
center of the next adjacent section
bolus phase - Answer-In this phase, the arterial structures are filled with contrast and
brightly displayed on the image. Contrast has not yet filled the venous structures. Also
called the arterial phase.
non-equilibrium phase - Answer-In this phase the contrast is still brighter in the arteries
than in the parenchyma of organs, but now the venous structures are also opacified,
This phase begins 1 minute after the start of the injection and lasts only a short time.
Also called the venous phase.
equilibrium phase - Answer-In this phase the contrast is largely emptied from the
arteries, is greatly diluted in the veins and has soaked the organ parenchyma. Also
called the delayed phase.
CVAD - Answer-venous catheter designed to deliver medications and fluids directly into
the superior vena cava, inferior vena cava, or right atrium
,PICC - Answer-long catheter that is inserted through the large veins of the upper arm
and advanced so that its tip is located in the lower one third of the SVC
Tunneled catheters - Answer-inserted into the targeted vein (often the subclavian)
underneath the skin, i.e., Hickman, Broviac, and Groshong
Non-tunneled catheters - Answer-larger caliber devic than PICC, inserted into a
relatively large, more central vein such as the jugular, subclavian or (less commonly)
the femoral vein
Tumors and other disease processes always have different attenuation coefficients than
those of their surrounding tissue. - Answer-False
For a patient's consent to be valid, she must be considered competent to make the
decision at hand and her consent must be voluntary. - Answer-True
In communication, you should assume that a nonresponsive patient cannot hear you. -
Answer-False
Communication is the transmission of meaning. - Answer-True
What qualities must the CT technologist look for in an established IV site when
administering IV contrast?
Please choose all that apply. - Answer--ensure that the line is patent
-evaluate the site for appropriateness for contrast media injection
-turn off existing medication, if OK's by nurse or physician
-ensure that IV gauge is appropriate for contrast media protocol
Conventional radiography barium suspension cannot be used in CT. - Answer-True
A number of independent studies have established a link between effective
communication and a reduction in malpractice claims. - Answer-True
Because the data selected for SFOV are a subset of all the scan data available, the
SFOV cannot be larger than the DFOV. - Answer-False
The half life of IV contrast for patients with normal renal function is 4 hours. - Answer-
False
In general the shortest gantry revolution time ( such as 0.4-0.5) must be used for most
CT studies. An exception to this rule is CT evaluation of a large patient, where use of
longer gantry rotation time helps increase total tube current. - Answer-True
Which is NOT a goal of the questions included on the CT history? - Answer--choosing
the most intelligent technologist
, -choosing the proper radiologist
What barrier to communication is likely to occur when the receiver doesn't like portions
of the sender's message? - Answer-receiver distortion
Which is true about meanings with respect to communication? - Answer-meanings are
not entirely contained in the message. They are interpreted by the message receiver.
Which method of contrast administration is programmable for uniphasic, biphasic and
triphasic injections? - Answer-mechanical or power injection
Which factors that affect the degree of contrast enhancement in human tissue are
controllable by the technologist? - Answer-pharmokinectics
Which of the following would be considered high risk for CIN? - Answer-patient with
diabetes mellitus and pre-existing renal insufficiency
Comparing the reported rate of adverse reaction: - Answer-LOCM are much lower than
HOCM by a factor of approximately4 to 5 times
Contrast reactions that are accompanied by a temporary drop in blood pressure,
bronchospasm, facial edema, urticaria, and laryngeal edema are generally classified as:
- Answer-moderate reactions
Which factors affect viscosity of an intravenous iodinated contrast agent?
1. iodine concentration
2. lipid solubility
3. total volume delivered
4. temperature of the agent - Answer-1 & 4
A contrast material that is of substantial higher density than that of the surrounding
structures can be referred to as a ___________ agent. - Answer-positive
When does contrast enhancement typically reach a near-peak in the aorta? - Answer-
From 15 to 22 seconds after the start of the injection
Which is the preferred venous access site when a mechanical injector is used? -
Answer-antecubital or large forearm vein
For what flow rate is a 20-gauge or larger catheter preferable? - Answer-2-4 mL/kg
By how many Hounsfield units must two tissues differ to be visibly different on a CT
scan? - Answer-at least 10 HU
Which should not be used for verifying a patient's identity? - Answer-The name posted
above the patient's bed
