Small focal spots make possible: (1) thin slices (2) high resolution (3) low resolution
Most commands from the CT tech are received by the:
C) operator's console
What is the Anode target material out made of?
In order for an x-ray photon to be measured it must: (1) enter the detector chamber (2) be absorbed by the detector material (3) be converted to a measurable event
Which is TRUE regarding solid state detectors? (1) x-ray photons cause the detectors to generate a flash of light (2) they are the detector type used on most CT scanners today (3) they can be used in both 3rd and 4th Generation CT systems
The CT x-ray tube rotates around the patient to: (1) keep the tube cool (2) generate projection views at different angles (3) minimize the x-ray dose to the patient
B) 2 only
For MDCT, the collimator selects the thickness of the x-ray beam which spreads over multiple rows of detectors. What determines the final slice thickness?
B) image recon
True/False: MDCT collect information from multiple anatomical slices in each rotation of the x-ray tube.
CT tube voltages ranges between ____ kV.
D) 90 - 140
Which does NOT affect the quantity of x-rays that completely penetrates the patient? (1) the distance that the x-ray photons must travel on their course through the body (2) the molecular composition of the tissues through which they pass through (3) the type of detector material used
B) 3 only
Which statement is FALSE regarding occurrences after an x-ray photon penetrates the detector aperture? (1) photon can pass through the detector unmeasured (2) photon is converted completely into an electron (3) the measured signal is enhanced by an amplifier
B) 2 only
Which system component converts the projection attenuation data into the proper digital form for the array processor?
Tungsten is used as the target material on the tube's anode because it has a ___ atomic number and a ___ melting point.
C) high, high
___ allow(s) remote authorized individuals to connect to a server in a secure fashion using the routing infrastructure provided on a public network (ie internet).
What is the purpose of the pre-patient collimator in MDCT?
D) reduce patient dose
CT consists of an anode and a cathode, which is positive and which is negative?
C) +, -
Which are NOT commonly used on today's commercially available CT Scanners?
(1) xenon detectors
(2) 4th Generation technology
(3) continuous rotation technology
The number of electrons that flow from the cathode to the anode in the tube is controlled by:
CT is commonly referred to as all of the following EXCEPT:
D) digital subtraction angiography
Which is/are characteristic radiation?
(1) collision between an incoming electron and the nucleus of the target atom
(2) slowing down of an incoming electron due to the effect of passing close to the positive charge of the nucleus or target atom
(3) collision between an incoming electron and an inner-shell electron of a target atom
D) 3 only
X-ray photons are produced by a fast-moving electron:
(1) colliding with an atomic nucleus
(2) passing close to an atomic nucleus
(3) colliding with an electron within an atom and ejecting it
Which is a component NOT normally located in the gantry of a modern CT system?
D) array processor
Increased ___ will increase the likelihood that a given x-ray will penetrate a material.
(3) exposure time
C) 1 only
Which is the standard that's used to achieve compatibility for image transfer between various imaging modalities viewing stations, and printers in a hospital?
CT images can be directly scanned in planes other than transverse by:
(1) orienting the patient's body part so that it is not perpendicular to the x-ray beam
(2) tilting the gantry
(3) changing the x-ray beam angle
What control does the operator have over the x-rays in a CT exam?
C) the energy level and quantity of the x-rays can be selected
The slip ring on continuous rotation CT scanners:
(1) prevents high voltage cables from winding up
(2) allows the exam to commence more rapidly
(3) eliminates the need for the reversal of gantry frame rotation
Which generation scanner did NOT use a fan beam?
D) 1st Gen
What did the 1st Generation CT scanner use?
B) pencil beam
The patient table:
D) may move continuously during the scan
Which is NOT part of the CT tube?
Breamsstrahlung radiation does NOT include:
(1) collision between an incoming electron and target atom's nucleus
(2) collision between an incoming electron and the target atom's inner shell electron
(3) slowing down of an incoming electron due to the effect of passing close to the target atom's positively-charged nucleus
D) 2 only
Which is NOT a function of a PACS?
D) recon of the image from raw data
Which statement is FALSE regarding the collection of CT data?
B) long scan times are more desirable because they average out motion artifacts
The mA determines the:
C) quantity of x-ray photons
C) is accomplish by physically blocking x-rays
Which statement(s) is TRUE?
(1) kV is the voltage potential between the tube cathode and anode while mA ultimately controls the filament current and, thus, the temperature of the filament
(2) kV controls the energy level of the x-ray photons and mA controls the number of x-ray photons emitted from the x-ray tube
(3) although kV and mA affect the operation of the x-ray tube, the two have NO bearing on the image quality
Which statement(s) is FALSE regarding CT systems? (1) they are limited to non-oblique transverse scanning
(2) they cannot generate a straight coronal or sagittal image
(3) they have no moving parts
X-rays are used in CT because:
D) they penetrate the body according to specific attenuation characteristics of each tissue
Scatter radiation is caused by:
A) deflections from the original trajectory of an x-ray photon through the patient
The main purpose of the detector is to:
A) capture x-ray photons and convert them to a measurable signal
The operator's console may include:
(3) graphic input device
___ scanner design was the first to acquire 4 slices in a single rotation.
C) multi-row detector
X-rays are produced when fast moving electrons collide with a target material and ___ energy.
The cathode filament:
A) helps determine the size of the focal spot
On a SDCT scanner, what technical factor determines the slice thickness?
B) pre-patient collimator
X-rays are produced whenever fast-moving electron collide with any form of matter because it:
(1) splits into 2 x-ray photons of equal energy upon impact
(2) loses kinetic energy which is converted into the emission of an x-ray photon
(3) converts the electron it collides with into an x-ray photon
A) 2 only
Which is TRUE regarding MDCT scanners?
(1) the size of the detector arrays along the z-direction may be different
(2) the attenuation information from adjacent detector arrays may be added together to generate thicker slices
(3) all of the detector arrays may or may not be used
Tube interscan delay time refers to:
B) the time between the end of one scan and the beginning of the next scan during which the tube will cool
___ made helical imaging possible.
B) continuous rotation scanners
Which technology do MDCT scanners employ?
D) 3rd Gen
Which CT scanner designs does NOT use an x-ray tube?
C) electron beam CT
In a radiology department, a ___ is an example of a "client" on a network. (1) CT scanner
(2) viewing console
(3) printer for Dx images
The enormous heat that builds up in the tube is caused by the:
A) collision of the electron beam with the tungsten target
On a SDCT scanner, collimation:
(1) controls the slice thickness
(2) minimizes the patient dose
(3) reduces the detection of scatter radiation
___ is the mathematical process used by SDCT scanners to reconstruct CT images from raw data.
C) filtered back projection
MDCT scanners capable of collecting 64 slices in a single rotation do NOT:
C) use filtered back projection as their method of image reconstruction
The x-ray beam used in CT scanning is ___ the patient's tissues.
(1) reflected off of
(2) attenuated by
(3) generated by
A) 2 only
A retrospective recon, in which the recon FOV is varied, uses:
B) raw data
CTA images come from ___ scan.
D) 2 only
The actual attenuation data measured by the detector from all projections during a scan is contained in the CT ___ data.
C) 3 only
Using ___ recon filter would decrease the appearance of noise in a CT image.
A) 3 only
A kernel is a:
D) filter applied to the raw data
Iterative recon is:
C) a complex cycle of correction calculations applied during image recon in order to reduce noise in the image
From which of the following can the most Dx MPR be generated? (1) stacked transverse images from a helical scan
(2) stacked transverse images from a conventional scan
(3) stacked localizer scans
A) 1 only
A pixel is a:
A) single 2D picture element within the image plane
If an image matrix has 360 rows and 360 columns, how many pixels are there in the image?
#pixels = 360x360 = 129,600
Important clinical benefits of iterative recon include: (1) ability to reduce radiation dose without compromising image quality
(2) no longer needing to perform MPR recons
(3) reduction in noise seen in the image
Which statement is FALSE regarding 3D SSD?
A) the volume data is created by combining transverse, SAG, and COR recons
A helical scan performed on a 64 slice MDCT scanner is recon'd with:
B) cone beam recon
A CT system manufacturer has a scanner in which the focal spot of the x-ray beam can move to two, slightly separated, distinct locations. What benefit does the dual focal spot provide compared to an identical scanner with a single focal spot?
(1) #projections is doubled
(2) #rays in a single projection is doubled
(3) the patient dose is halved
B) 1 only
A ___ scan uses only a single projection.
C) 3 only
What does convolution do to the image quality when it is added to the back projection recon process?
A) enhances important characteristics of attenuation profiles thus reducing streak and star artifacts
The ___ move(s) during a helical scan on a 3rd Gen scanner.
(1) x-ray tube
(2) patient table
(3) detector elements
Which is a recon technique applied to the raw data after the primary recon has already been accomplished?
D) retrospective recon
A smooth, or low-pass, recon filter is typically NOT selected for a(n) ___ exam.
Which is NOT an advantage of helical study compared to a conventional CT study?
C) offers the best image quality for a brain exam
cuz gantry tilt cutting off bony streaking
An increase in ___ does NOT occur in the resulting images when applying a sharp, or high-pass, recon filter during the image recon of the raw data. (1) contrast resolution
(2) edge enhancement
(3) the appearance of noise
D) 1 only
Which utilizes convolution? (1) 3D SSD
(2) fourier transform
(3) filtered back projection
B) 3 only
___ yields an image that appears 3D but also shows anatomical details above and below the 3D surface.
__ may have to be edited from the data set to get a Dx MIP of a CTA.
In which technique are tissues other than the surface of a structure excluded by setting a threshold value and eliminating pixels above or below that threshold?
B) 3D SSD
True/False: The amplified electrical signal obtained from the detectors must be digitized.
True/False:Digital CT images are numerical representations of cross-sectional anatomy.
True/False: Digital signals may be formed by sampling analog signals at discrete time intervals.
MPR recons are performed on:
(1) image data
(2) raw data
(3) attenuation data
C) 1 only
___ allows helical data to be converted into planar raw data.
In the diagram, which x-ray tube position will produce a lateral localizer image?
Which may occur during the interscan delay of a conventional scan on a continuous rotation scanner?
(1) table position incremented
(2) tube continues to rotate in the same direction as during the scan
(3) tube assembly makes a 360* rotation
On a 3rd Gen SDCT scanner, if there are 715 detectors and there are 900 projections in a full scan, how many samples of attenuation data are collected for the raw data of a single slice if the scan calls for an overscan of 400* rotation?
The ___ determines the intensity of the laser beam in a laser camera.
C) pixel values in the image data
The pencil thin section of the x-ray fan beam that strikes a single detector is called:
3D SSD displays are performed on CT:
(1) image data
(2) raw data
(3) attenuation data
C) 2 only
Which is TRUE regarding the slice thickness of an image recon'd from a helical scan?
(1) on a MDCT scanner, the thickness is equal to the beam collimation
(2) on a SDCT scanner, the thickness can be varied retrospectively
(3) on a SDCT scanner, the thickness is equal to the beam collimation
A) 3 only
A) do NOT demo detail beneath the brightest pixel
Which determinants of CT image quality is responsible for how grainy or speckled a CT image appears?
An increase in ___ will result in hardening of the x-ray beam.
(1) tissue density
(3) tissue thickness
Which are possible results of partial voluming?
(1) decreased edge sharpness
(2) increased resolution
(3) misleading CT numbers
Resolution is NOT dependent on:
(1) matrix size
(2) recon FOV
(3) scanned FOV
C) 3 only
Which is NOT directly proportional to mAs?
B) the mean energy of the x-ray photons leaving the tube
Which technique has the highest patient dose assuming all other parameters remain the same?
B) mA=150, time=3sec
Which will result in an increased voxel size?
(1) decreased recon FOV
(2) increased matrix
(3) increased slice thickness
A) 3 only
Which is the conversion equation from CT Number to Hounsfield unit?
A) CT number = HU
If the radiologist requires 2mm thick contiguous slices through the pituitary, and 2.4cm of coverage, how many slices are needed?
2.4cm x 10mm/1cm = 240mm/2mm = 12 slices
CT numbers ___ would appear black if a window width of 400 and window level of -100 are used.
400/2 = ±200
(right side/low end): -200 + (-100) = -300
(left side/high end): +200 + (-100) = +100
If a recon FOV of 32cm and a 512x512 matrix are used, the pixel size is ___mm
0.625 x 0.625
pixel = DFOV/matrix = (320mm)/(512) = 0.625mm
Which is a reason to increase pitch?
(1) greater volume of anatomy can be covered in a given time
(2) radiation dose to patient can be increased
(3) given volume of anatomy can be covered faster
Which would be used to better visualize low contrast resolution?
(1) decreased mAs
(2) sharp recon filter
(3) narrow window with
D) 3 only
If a thin slice is used, which would help reduce the apparent image noise?
A) increased mAs
A set of images is recon'd with 150mm recon FOV. Keeping all other parameters constant, a 2nd set of images is recon'd with a 300mm recon FOV, and then magnified so that the anatomical structures in the 1st and 2nd set appear the same size. Which statement(s) is FALSE?
(1) the resolution of the 2nd set is better than the 1st set
(2) the patient dose of the 1st set of images is higher than 2nd set
(3) the apparent noise in the 2nd set is more pronounced than the 1st set
The ___ determines how penetrating the x-ray beam will be.
The smallest object that can be resolved if a recon FOV of 24cm and a 512x512 matrix are used is ___mm.
Which parameter(s) affects the contrast of an image?
Which pitch value would stretch the x-ray helix the most?
There are ___ total pixels in a 1024x1024 matrix.
True/False: For a given distance of coverage, as recon FOV increases, patient dose increases.
True/False:For a given distance of coverage, as slice thickness increases, patient dose decreases.
True/False: For a given distance of coverage, as pitch increases, patient dose decreases.
True/False: Magnification decreases the size of displayed anatomy.
Compared to a CT scan protocol without iterative recon applied, when using iterative recon, which scan parameter is reduced?
A CT Number Calibration Test should be performed:
___ the window ___ will make the image appear darker so that bony structures can be evaluated.
B) increasing, level
Which is the expected result of a CT Number Calibration Test performed on a water phantom?
B) 0 ± 3
___ affects the CT number of water.
C) no imaging parameter
Which parameter allows adjacent slices to be overlapped without increasing patient dose?
A) reconstruction interval
Which can be changed retrospectively? (1) slice thickness from an MDCT
(2) slice overlap from a SDCT
(3) slice thickness from a SDCT
Which would be used in a high resolution study of the temporal bones? (1) reduced slice thickness
(2) reduced recon FOV
(3) sharp recon filter
The ability to scan a moving organ without seeing motion artifacts on the images is an example of an exam with high:
C) temporal resolution
On a conventional CT scan, if we want 5mm slices with 1mm overlap, the table increment should be ___ mm.
On MDCT, the final recon'd slice thickness is determined by the:
B) #detector rows and the detector size whose attenuation data gets combined
Which parameter is responsible for partial voluming?
B) slice thickness
The distance that the table travels between slices is called ___.
Which parameter causes helical slices to be recon'd so they overlap?
B) recon interval
Which does NOT occur when recon FOV is decreased?
(1) spatial resolution is increased
(2) pixel size is increased
(3) noise is increased
If a calcification with a CT number of +300 appears pure white on an image, which could be the window settings selected?
(1) WL = 0, WW = 500
(2) WL = +300, WW = 500
(3) WL = +100, WW = 300
A BUN of ___ mg/dl is considered outside the normal range. (1) 10
D) 3 only
To modify a standard CT protocol so that it is appropriate for children, which parameter(s) should be decreased? (1) pitch
Which does NOT minimize the patient dose?
B) decreasing distance between x-ray beam and patient
Air in the pleural space causes the lung to collapse, which is termed:
Which medical device is most often used in oxygen delivery?
C) nasal cannula
True/False: A pulse oximeter works by passing a beam of red and infrared light through the capillary bed.
True/False: Normal O2 saturation is 85-100%
Normal O2 range = 95-100%
Which does NOT test for renal function:
The most sensitive trimester for a developing fetus/embryo is:
Platelets are small:
A) cell fragments necessary for cloating
A creatinine level of 3.1 mg/dl indicates the:
(1) kidneys are not removing waste products from urine
(2) value is above the normal range
(3) contraindicated for IV contrast injection
True/False: The patient should be removed from the CT suite to treat cardiac arrest.
Which PT are considered outside the normal range?
True/False: A claustrophobic patient can arrive for the CT scan prepared with a prescription sedative.
True/False: Monitoring patient during a scan or procedure is unnecessary if prior history or condition does not indicate the need for monitoring.
If the mA of a 2sec brain scan is doubled and all other parameters are constant, the dose is:
Renal function refers to which organ?
Which reduces patient dose at the expense of increasing apparent noise?
During a CT scan, the patient must be monitored:
A) visually and verbally
___ offers standardized lab values indicating the blood's ability to coagulate for patients taking anticoagulant medications.
When reviewing the images from a helical scan, a subtle suspicious area of possible pathology is noticed. What could be done WITHOUT increasing patient dose?
(1) re-scan the region using thinner slices
(2) retrospectively reconstruct the slices so that they overlap
(3) repeat scan but decrease pitch
A) 2 only
True/False: Metformin has the same precautions as Glucophage, Glucovance, and Glucagon.
Only same as first two, not Glucagon.
Which is NOT typical indication of shock?
CPR must be administered to a cardiac arrest victim within a maximum of ___ minute(s) before there is risk of brain damage.
___ mmHg is within the normal range of diastolic pressure for adults.
The most important consideration in the care of an unconscious patient is to ensure the ___ are clear and open.
What is the normal adult respiration per minute range?
Which lab tests often indicates the necessity for a CTA or NM to rule out pulmonary embolism?
What is the normal O2 blood saturation?
Which vital sign is considered abnormal?
D) adult BP of 165/98
The ARRT Code of Ethics is considered a ___, while the Rule of Ethics is a ___.
D) conduct guideline, enforceable
Which is a good effective dose estimate for a CT Head scan?
A) 2 mSv
What does the lab test PTT stand for?
partial thromboplastin time
Which lab tests should be considered before administering IV contrast? (1) BUN
In a normal EKG, the ___ wave represents atrial contraction.
ON a MDCT scanner, a radiation penumbra may be found:
A) on 1st and last slices of the slice volume
Which technique minimizes the patient dose in a coronary calcium scoring exam?
A) prospective synchronization
Which radiation dose measurement accounts for helical studies on MDCT scanners and considers the total volume of irradiated tissues?
A normal pulse rate for an infant is ___ bpm.
What are the radiation shields used in CT made out of?
What should be done if extravasation is noticed at the injection site?
B) immediately stop injection
Which phase of IV contrast enhancement will occur first?
A) bolus, non-equilibrium, equilibrium
Which oral contrast is better for opacifying the distal small intestine?
(1) barium sulfate
(2) non-ionic iodine
(3) ionic iodine
C) 1 only
The definition of osmolality is the ___ the contrast agent solution.
B) concentration of molecular particles in
When a contrast agent is injected directly into the joint space it is termed:
Which characteristics of an IV contrast affects patient tolerance? (1) iodine concentration
An IV contrast media viscosity can be reduced by ___.
The heating unit on a power injector is for ___ of the contrast agent.
B) decreasing the viscosity
A difference of ___ HU between the aorta and IVC would indicate the non-equilibrium enhancement phase.
A delay about ___ sec after the start of IV injection should be used for a CT Chest exam.
Iodine oral contrast would be selected instead of barium sulfate because:
(1) it passes through GI more quickly
(2) the trauma patient may have a perforated bowel
(3) the contrast stays more dense in the distal GI tract
The most common gauge range of IV catheter used in CT is ___.
If there is doubt regarding the sterility of the contrast media, the contrast should be ___.
An indication of IV contrast injection is to rule out:
(4) Grave's disease
C) 2 only
The osmolality of plasma is ___ mOsm/kg.
(1) less than LOCM at 285
(2) less than LOCM at 300
(3) less than HOCM at 285
(4) less than HOCM at 400
A) 1 only
True/False: The standard peripherally inserted central catheter, like those used for chemotherapy, are required for CT IV contrast studies.
A delay of about ___ sec after the start of IV contrast injection should be used for a CT Neck.
True/False: According to ACR guidelines, under no circumstances should IV contrast be administered to a pregnant patient.
True/False: According to ACR guidelines, IV contrast may be administered when it is not prudent to wait to obtain the clinical information until after the pregnancy.
True/False: According to ACR guidelines, IV contrast may be administered if the clinical information obtained will affect the care of the patient and fetus during pregnancy.
What is the appropriate care to give to a diabetic patient?
(1) if the patient is using Metformin, advice them to stop its use 48hrs before IV contrast injection.
(2) if the patient is using Metformin, advise them to resume its use 48hrs after IV contrast administration only after kidney function has been reassessed and determined to be normal
(3) if IV contrast is required, use LOCM
Which may help reduce adverse reactions resulting from IV contrast injection?
(1) use HOCM
(2) increase flow rate
(3) administer an antihistamine prior to the exam
C) 3 only
To best visualize the stomach wall, what should the patient drink last?
(3) barium sulfate
A) 1 only
There is significant enhancement of the liver compared to tumors during the ___ phase, but during the ___ phase, there is the possibility of tumor enhancement, which may make hepatic tumors isodense with liver tissue.
D) non-equilibrium, equilibrium
Exams to rule out ___ would indicate the need for IV contrast in the chest.
(2) hilar mass
(3) aortic dissection
The typical scan delay for a pancreas study is:
C) 50-60 sec
Why is the cephalic vein a less desirable site for injection than the basilic vein?
C) the flow is impeded with the patient's arms raised
How long does it take to inject 150 mL with a flowrate of 2cc/sec?
A) 75 sec
Viscosity is a measure of a fluid's ___.
Which is a result of injecting a hypertonic solution into the vascular space?
A) there is net movement of water into the vascular space
The portal venous phase occurs about ___ after IV contrast injection.
D) 60-90 sec
An injection rate of ___ cc/sec will maintain a dense bolus of IV contrast for a CTA exam and will be tolerated by most patients.
Which is associated with a bi-phasic study of the liver?
(1) using two contrast injection rates
(2) having 2 images per slice position
(3) lesion differentiation with arterial and portal venous blood supplies
(4) arterial occurs in the equilibrium phase, while portal venous happens during the non-equilibrium phase
A CT Brain exam to visualize MS plaques may be made more sensitive by using ___ delay after the contrast injection.
A) 45 min
Low osmolar contrast media: (1) typically has the same concentration of particles as plasma
(2) typically has the higher concentration of particles than plasma
(3) tends to cause more adverse reaction than HOCM
(4) is the preferred contrast type for diabetics over HOCM
The hepatic arterial phase occurs about __ sec after IV contrast injection.
Which is NOT a typical adverse reaction to oral contrast?
What type of "negative" contrast is administered rectally for virtual colonoscopy exams?
Which statement is TRUE regarding barium sulfate contrast used in CT exams?
D) less concentration is used for CT than for conventional radiology
The contrast between a lesion and the surrounding tissue may ___ following injection of contrast media.
(2) remain unchanged
(3) be degraded
Contrast agents containing barium sulfate:
(1) enhance structures because they are absorbed into the blood stream
(2) enhance structures because they are absorbed through the small intestine
(3) remain unchanged as they travel through the body
B) 3 only
Which types of contrast has NO application for a CT T-Spine? (1) oral
B) 1 only
In which studies might cranial nerve XI be visualized?
B) soft tissue neck
In order to generate a 3D SSD rendering of the hips, the ___ data is used directly by the 3D recon software.
Which is the appropriate range of coverage for a coronal sinus study?
A) from anterior aspect of frontal sinus to dorum sella
Which is NOT a reason for using thinner slices in the posterior fossa compared with the more superior regions of the brain?
(1) improve spatial resolution
(2) decrease patient dose
(3) reduce streak artifacts
D) 2 only
A localizer image in which orientation(s) should be used to set up axial slices so that they can be parallel to the plane of a specific lumber disk?
Which is TRUE regarding CT spine exams?
(1) IV contrast is usually not needed to r/o herniated disk(s)
(2) the entire t-spine is not routinely scanned with transverse CT slices
(3) SAG and COR images of an adult spine may not be directly collected from a CT scan
Which is NOT an indication of a herniated disk?
(1) hypertrophy of the inferior articulating process and lamina
(2) deformity of the posterior disk border
(3) displacement of epidural fat
B) 1 only
Which window settings provides the best tissue differentiation of the soft tissues of the supratentorium?
D) WW = 100, WL = 30
On a CTA lower extremity to assess atherosclerosis, coverage should extend from ___ to ___.
abdominal aorta/diaphragm, ankles
What is the primary reason to have a patient phonate the letter "e" during a CT larynx exam?
A) demos vocal cord mobility
Which combos of scanning parameters is best for evaluating abnormalities within the petrous pyramids of the temporal bones?
D) algorithm = sharp, WW = 2500, slice = 0.5-2mm
Which should NOT be part of a CT brain perfusion exam?
D) do not restrain patient's head during exam
CT brain perfusion:
B) is typically performed to evaluate stroke
Which is necessary to quickly and accurately Dx stroke?
(1) eval for ischemic but viable tissue
(2) eval for vascular occlusion
(3) establish if there is an intracranial hemorrhage
Which is FALSE about a CT Runoff exam?
B) coverage should extend from upper abdominal aorta/diaphram to popliteal artery bifurcation
Indications for CT Head include:
Which is NOT a location where one would expect to find CSF?
(1) subarachnoid space
(2) 4th ventricle of the brain
(3) subdural space
D) 3 only
Which scanning plane is best for evaluating the anatomical relationship between pituitary and sella turcica?
Which would NOT enhance during the 1st several minutes of a post-contrast CT Neck?
D) lymph nodes
From the ___ above and below the disk space should be scanned if only 1 intervertebral disk space was of interest.
What CT exam will cranial nerve VII be seen?
If we want to generate a Dx 3D SSD of the C-spine, how should the scan be performed?
D) at a single angle and no gaps through the affected regions
What can be done to reduce the lordotic curve in a CT L-spine exam?
place wedge/pillow under the knees
For CT brain exams, the reference lines for axial slices are:
(1) crantomeatal line
(2) infraorbitomeatal line
(3) orbitomeatal line
To compensate for increased noise when reducing slice thickness, what and how should that parameter be varied?
For which condition of the brain should IV contrast NOT be administered?
A) suspected atrophy
For a routine CT Pelvis, what gantry tilt is used?
For CT Pelvis, from __ to __ should be scanned.
D) iliac crest, symphysis pubis
Which window setting is best for bone window of a CT Pelvis?
B) WW = 2000, WL = 350
Which is a reason for inserting a tampon into the vagina for a CT Pelvis?
C) helps visualize the vaginal canal
Which is NOT recommended for a screening CT colonoscopy exam?
(1) both prone and supine positioning
(2) post-processing to visualize inside surface of bowel
(3) 200 mAs
C) 3 only
TRUE/FALSE: A high calcium scoring is evidence of stenosis.
False. High chance of but not proof of.
In order to assess cardiac function, the ___ is evaluated.
B) left ventricle
The ___ view is used to evaluate cardiac function.
B) short axis
Normal ejection fraction is greater than ___%
A CT urogram requires ___ of water to be consumed within ___ of the exam.
A) 2 qt, 45min-1hr
Which window settings is best for a CT Liver exam?
B) WW = 140, WL = 60
The result of the bifurcation of the abdominal aorta is the left and right ___ arteries.
C) common iliac
TRUE/FALSE: The left lobe of the liver is more anterior than the right and caudate lobe, while the caudate lobe is more medial than the right lobe.
Which affects the severity of the metal artifacts?
(1) quantity, composition and shape of the metal
(2) number of data sampling points
(3) slice thickness
Which may occur if the patient's arms are not raised during a CT Chest with a 33cm scan FOV?
(1) beam hardening
(2) cone beam artifact
(3) out-of-field artifact
A(n) ___ artifact can be created when attempting to correct for a cupping artifact by applying a correction algorithm too aggressively to the data for a head image. This results in the ___ of the image appearing too bright.
A) capping, center
CT x-ray tube arcing can occur because of ___ the x-ray tube.
(1) impurities in the oil outside
(2) tungsten solids in the oil inside
(3) tungsten gas inside
Which will have the least likelihood of producing edge gradient artifacts?
A) thin slices with full scan
___ in the image is a possible manifestation of patient motion.
On a CT Brain, a cupping artifact would appear brighter:
A) at the periphery of the brain
A cone beam artifact may look like stars:
D) coming from structures around the edge of the image
A CT artifact is:
B) an image anomaly
Beam hardening refers to the increase in the:
(1) average beam energy
(2) # of photons reaching the detectors
(3) # of low energy photons reaching the detectors
D) 1 only
Which would reduce noise?
D) increased window widths, mAs, and slice thickness
The service engineer should NOT be notified about:
(1) consistent circle artifacts
(2) frequent bad streaks throughout entire scan
(3) frequent bad streaks on the inferior of the head scans
A) 3 only
Which strategies minimizes beam hardening artifacts from dense contrast media?
(1) diluted contrast
(2) scan with a slight delay
(3) scan caudiocranial
Which would display the greatest amount of partial volume artifact?
A) 10mm from 20 slices
Which would increase severity of edge gradient effect?
(1) scanner with a small aperture
(2) scanner with a low data sampling rate
(3) using thin slices
C) 2 only
Which strategies will eliminate a ring artifact?
A) recalibration of detector elements
Which could result from beam hardening?
(1) CT # inaccuracies
(2) cupping artifacts
What causes cupping effect?
C) attentuation of low energy photons
What causes 2 parallel lines to appear on a localizer image?
C) two faulty detector elements
What would decrease beam hardening?
(1) increasing kVp
(2) increasing mAs
(3) increasing slice thickness
D) 1 only
A(n) ___ artifact is a streak artifact which arises from a high spatial frequency interface between tissues with a great difference in the density.
C) edge gradient
In which direction are streaks from the edge gradient effect orientated?
D) parallel to the direction of the sharp density difference
Which would NOT help differentiate pathology from a partial volume artifact?
(1) rescan, decrease pitch, same slice thickness
(2) inspect adjacent slices
(3) collect additional thinner slices through suspicious region
B) 1 only
Which would reduce out-of-field artifacts?
B) increasing scan FOV
What causes cone beam artifacts?
A) using filtered back projection on beam thickness over 20mm
Which could result from partial volumizing?
(1) decreased edge sharpness
(2) ghosting of tissue boundaries
(3) inaccurate CT numbers
What results from a faulty detector element on a localizer image?
C) 1 parallel line along the long axis of patient table
What would result if the aperture filter of the x-ray tube removed even more low energy x-ray photons?
A) decreased beam hardening
What happens with decreased slice thickness?
A) decreased partial voluming and edge gradient artifact, but increasing patient dose