My Ct Flash Cards
Which of the following terms is not an indication for imaging of the renal arteries
- aneurysms
- stenosis
- kidney transplant
- cysts
Cysts
Hypertrophy of the facet of a vertebra is known as
Spondylosis
The total measurement of radiation that has traveled through a pt and falls on a single detector is called
Ray sum
———— describes a set of rules or directions for getting a specific output from a specific input
Algorithm
Whole body dose from a partial body exposure is quantified by
Effective dose
———- takes into consideration the variations in density of the object
CTDIw
The medium used to measure the light that is emitted from the scintillation crystal is called
Photodiode
Transmission of data to the computer is completed by the
DAS
——— occurs when multiple types of tissue are represented by a single voxel
Partial volume averaging
——- digitally represents a quantity of scanned pt tissue
Voxel
Pitch does not effect
Amount of gap or overlap between slices
——— is a measure of blood coagulation
PT
Prothrombin time (PT)
12-15 seconds
——- have the same osmolality as blood
IOCM—-
iso-osculatory contrast media
Ct number for muscle
50
—- describes the amount of X-ray energy absorbed in a unit of mass
Absorbed dose
—— accounts for the type of tissue that the radiation is deposited in
Effective dose
—— approximates the relative risk from exposure to ionizing radiation
Effective dose
—- is an estimation of the whole body dose equivalent that results form the partial body exposure the pt receives during a duct procedure
Effective dose
——- is the term used to describe the ability of xrays to ionize a volume of air
Exposure
Exposure is measured in ——-
Roentgens
—— is a graphical representation of a ct systems response to a spatial frequency
MTF
Modulation transfer function
How many different grayscale values can an image have
256
The patients raw data allows us to generate ——
Retrospective image reconstructions
MTF measures
Spatial frequency
A filtered beam that is more homogeneous is less susceptible to artifacts from a process know as —-
Beam hardening
A pitch of —- reduces the table speed for each gantry revolution and can increase image quality
Less than one
Ct number for dense bone
3000
White matter ct number
45
——- is a measure of the size of the smallest object of the smallest object that can be visualized in an image
Spatial resolution
The transverse plane is
Perpendicular to the direction of z axis
How does contrast flow through the heart
R atrium
R ventricle
L atrium
L ventricle
—- does not affect the image contrast or resolution
MAS
To calculate CTDI the acquisition must be
Contiguous
Filtered back projection uses what type of filter to remove the blurring that occurs with back projection
Convolution
Ct pet is utilized to measure the uptake of ————
FDG
Image acquisition in a ct pancreas exam typically occurs after ——
35-45 seconds
The area of the pt that is exposed to radiation is know as
Dose profile
The mathematical process used to create an image in which attenuation data are projected onto a matrix is known as
Back projection
The nephrographic phase of contrast enhancement occurs after which of the following
70-90 seconds
Spatial resolution within the x and y directions is known as
In plane resolution
Which of the following helps to determine the slice thickness of an image
Precollimater
Which of the following algorithms reduce image noise when using lower exposures while also preserving image quality
Interactive reconstruction
The solid state detector used in modern ct scanners is a
Scintillation detector
The connective tissue that surrounds the kidneys is the
Gerota’s fascia
In MSCT the number of slices acquired and the thickness of the slices is determined by the
Detector configuration
An infection acquired in the hospital is know as
Nosocomial
The liver receives 75 % of its blood from the portal vein and 25% from the
Hepatic artery
In order to obtain sufficient iodine opacification during a ct examination which of the following concentrations much be present
2-8 mg/ml
INR is used to standardize which of the following
Prothrombin time
The major and minor calyces make up the
Renal pelvis
A ct image has a window level of 300 and a width of 600 which of the following is correct
The ct number will range between 0 and +600
The smallest possible slice thickness is determined by the
Smallest single detector channel
Gas ionization detectors are primarily used in
3rd generation ct scanners
What is stenosis
Narrowing
At which level does the sma typically originate
L1
Perenteral administration is any ———- method of administration
Non oral
The utilization of half-scan reconstruction can improve
Temporal resolution
When an upper vertebral body slips over a lower vertebral body this is
Spondylolisthesis
Which of the following is measured in millisievert
- absorbed dose
- exposure
- effective dose
- curie
Effective
Cardiac diastole corresponds to which of the following
T wave
Which of the following is most likely to require images of less than 1mm in thickness
High res chest
-
-
Renal pelvis
Ureters
Bladder
(3 min post admin of iv contrast)
During a ct urinary track exam puts may be imaged in the prone position to better
Differentiate strokes within the urinary tract
True/false
Ct lung nodule is performed with a reduced technique
True
Absorbed dose is reported in
Milligray
Which of the following may result in misregistration of pt info
Motion
Windowing of a ct image controls
Contrast and brightness
Iohexol is a —- contrast material
Non ionic
The ability of the ct scanner to show small objects that are close together
Spatial resolution
——- is a measure of noise in an image
Standard deviation
DLP and CTDI are displayed on CT dose reports
Claudication maybe a clinical indication for
CTA runoff
The adnexa of the uterus is made up of the
Ovaries and fallopian tubes
——- is most likely to be used during a ct enterography exam
Neutral oral contrast
—— transmit acquisition data to the computer
DAS
ASSIGNING A VALUE TO THE ATtenuation signal that is created by the detector is know as
Linear attenuation coefficient
As it relates to the detectors stability is ——
The steadiness of the detectors response to the xrays
Directing electrons to tow different areas on the focal spot is referred to as
Flying focal spot
Which factor related to spatial resolution requires a 2x sample of the object, compared to the spatial frequency
Sampling
FWHM is a measure of
Effective section width
—— is the quantity of blood that moves within 100g of brain tissue in a min
Cerebral blood flow
At which vertebral level does the spinal cord end
L1-L2
When calculating dlp what relationship does scan length have with dose
It is proportional
——- is the total amount of exposure for an exam
DLP
Of the following which has a direct effect on pt dose
- window width
- mas
- matric
- DFOV
MAS
Increasing radiation dose to overcome the penumbra at the edge of the detectors is know as
Overbeaming
Which axis indicated width
X Axis
Gantry rotation affects ——- resolution
Temporal
Multi-segmont reconstruction has a direct impact on which of the following
Temporal resolution
Which is a non ionic contrast material
Iohexol
The term used to describe a filtration algorithm that removes blurring in an image during back-projection is
Convolution
The utilization of half-scan reconstruction can improve which of the following
Temporal resolution
Which of the following is not required to be included in the structured dose report
DFOV
The number of data channels active and the effective section thickness is know as
Detector configuration
Voxels that form a perfect cube are referred to as
Isotropic
MinIP is used to display
The minimum attenuation within a voxel
The mathematical process that uses data points above and below a slice to reconstruct an image is know as
Interpolation
The circle of Willis
- RL anterior cervbral arteries
- anterior communicating art
- RL internal cor art
- RL posterior cerebral arteries
- RL posterior communicating arteries
—— uses a convolution filter to remove blurring that occurs with back projection
Filtered back projection
What type of viewing allows for the review of large amounts of images quickly and in a continuous loop
CINE
The X-ray beam utilized in MDCT is know as
CONE BEAM
—— is used to describe the rate that photons pass through an area in a set amount of time
Photon flux
Images areas that contain objects with high variations in densities will have
High spatial frequency
—— can reduce image noise which helps improve the quality of the image while also reducing pt dose
Iterative reconstruction
What imaging plane is parallel to the metatarsals of the foot
Obli
Which imaging plane is parallel to the metatarsals of the foot
The oblique axial
——- will impact the volume of a voxel when adjustments are made
MPR
Transmission of data to the computer is completed by the
DAS
Which of the following does CTDI measure
The dose received in a single slive
Conversion of data into digital values is completed by the
ADC
——- is used to approximate the radiation dose for each section obtained during a helical scan
CTDI vol
Normal bun levels
7-20
Low oxygen level in the blood
Hypoxemia
Arterial systole corresponds to
P wave
