Mosby Random Test 2 Flashcards
How do you calculate the dimensions of a pixel?
by dividing the DFOV by the matrix size
how do you calculate the area of a pixel
by squaring the dimension
What is used in gas ionization CT detectors?
xenon
cupping artifacts most commonly occur in the
brain
At its distal end, the spinal cord tapers into the
conus medullaris
the primary clinical indication for non-contrast cardiac MDCT is
coronary artery calcium (CAC) quantification for the assessment of atherosclerotic disease
What abnormal findings will reduce the density of the liver?
fatty infiltrates
During which phase of contrast enhancement optimally demonstrates the relationship between pancreatic neoplasm and the surrounding vasculature?
arterial phase
complete cardiac diastole refers to
relaxation of the left & right ventricle
relaxation of L&R atria
t wave of ECG
The ability of a CT scanner to accurately image objects with similar densities is termed
contrast resolution or sensitivity Makeup
the interaction between x-ray and matter that is responsible for the production of scatter radiation absorbed by the PT and detectors is
Compton
normal range for systolic blood pressure in adults
95-140 mm Hg
During HRCT of lungs you scan during a full expiration to demonstrate
air trapping due to COPD and emphysema
Quantity of radiation dose received by the PT from a series of CT scans is called the
MSAD multiple-scan average dose
increase in avg of photon energy of a heterogeneous x-ray beam
beam hardening
used with PTs at risk of infection due to immunosuppression or some other form of debilitative disease
strict isolation
was know as protective or reverse isolation
the process by which electrons are produced at the cathode of a CT x-ray tube is
thermionic emission
the normal platelet count range for an adult is
140,000-440,000/mL of blood
The number, length, and organization of the individual detector elements in an MSCT system are referred to as
detector configuration
infection may occur indirectly through contact w contaminated objects known as
fomites
standard or soft tissue algorithms require
low spatial frequency
volume element
voxel
the typical range for possible pixel values in a modern ct system is
-1024 to +3071 HU
What organs are retroperitoneal
duodenum, pancreas, adrenal glands, kidneys, ureters, bladder
the period of peak hepatic parenchymal enhancement following rapid bolus injection of contrast is termed the
portal venous phase
normal range for INR
0.8-1.2
international normalized ration for prothrombin time
primary interaction between x-ray photons and tissue during CT
compton
CSF is produced in the
choroid plexuses
the primary advantage of an isotropic MDCT data-set is
high-quality multiplaner recons
the technique that allows the user to select the range of pixel values used in a 3D CT reformat is called
thresholding
ring artifacts are typically caused by
faulty detectors
Ct images that have been reconstructed from a portion of the data acquisition process in the hopes of reducing PT motion artifact is
segmented images
parenteral routes include
IV admin, intramuscular, subcutaneous, intradermal, and intrathecal
the purpose of IV contrast is to
increase contrast between adjacent structures and increase beam attenuation of enhanced structures
there circle of Willis is composed of
the anterior cerebral, anterior communicated, internal carotid, posterior cerebral, and posterior communicating arteries
typical dose of FDG (F-18-fluorodeoxyglucose) for PET-CT
10-15 millicuries
the ability of an object to attenuate the x-ray beam is assigned a value known as
linear attenuation coefficient
