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• portable CT fluoroscopy unit with a telescoping gantry
• used to acquire 3D Ct images and standard fluoroscopy during invasive or surgical procedures

the increase in CT density of a structure due to filling with positive contrast material

• Operating System
• the main software of the CT computer, controlling the utilization of the hardware resources including the available memory, CPU time disk space and ect...

Imaging planes that are perpendicular to each other

A Technique yielding a 3D model with the perspective of externally viewing the reconstructed objects

the tendency of an iodinated contrast medium to cause fluid from outside the blood vessel to move into the bloodstream

• Hyperdense streaking
• occurs when a portion of the patient has been positioned outside the scan field of view (SFOV)

Expansion of the primary beam in an MSCT system to ensure that all detectors of the array are exposed to xrays of equal intensity

CT images produced with a reconstruction interval that is less than the section width

The process of applying radiation dose before and after the acquisition volume to ensure sufficient data collection for the interpolation algorithms of the helical CT reconstruction

• Picture Archival and Communication System
• Responsible for storing, retrieving, distributing and displaying CT and other digital medical images

• the delayed arterial enhancement phase
• happens about 35-45 seconds after the start of contrast injection

3mL/sec or greater

the ability of a computer to perform multiple functions simultaneously

an error that occurs when a structure is only partly positioned w/in a voxel and the attenuation for the object is not accurately represented by a pixel value

• Inaccuracy in pixel values
• occurs when the associated voxels contain attenuation coefficients for multiple tissue types
• the values are averaged together to yield a single pixel value that attempts to represent an assortment of different materials

• AKA: immersive rendering
• a technique yielding a 3D model with the perspective of being w/in the lumen of the object, similar to an endoscopic view

a quality control device typically composed of a radiolucent plastic material containing specialized inserts that is used to measure specific image quality criteria

a device used by a solid state CT detector to convert the light emittted by scintillation crystal into a proportional electronic signal

the rate at which a quantity of xray photons passes through a unit area over a unit time

a form of parallel processing used by a computer to improve computations speed

the relationship b/w collimation and table movement per gantry rotation

• AKA: Picture Element
• refers to the individual boxes arranges in the matrix used to display the CT image

• AKA: CT Number
• relative value assigned to each pixel to quantify the attenuation occurring in each voxel comparison with the attenuation of water

• Point Spread Function
• a measure of Ct systems in plane spatial resolution that evaluates the amount of spread inherent in an orthogonal (right angles) image of a thin wire

• Consisting of spectrum of differing energies
• used to describe the beam of xrays

Period of peak hepatic parenchymal enhancement when contrast material redistributes from the blood into the extravascular spaces

60-70 seconds after the start of contrast

• a method of improving the temporal resolution of the MSCT system during examination of the heart and mediastinum
• Data are acquired in an axial "step and shoot" mode and only during the diastolic portion of the R-R interval

the initial construction of the acquired raw data into CT image data with selected DFOV, algorithm, image center, ect

• minimal increase in attenuation demonstrated by a structure that typically does not enhance following intravenous contrast administration
• most common used to eval cysts

an electronic device placed on a patients finger, toe or earlobe to measure pulse and blood oxygen levels

measurements of scanner performances through quality testing procedures and evaluation of the test results

the implementation of corrective action to improve any identified performance inadequacies of CT system

the transmission measurement obtained by the detector used to mathematically reconstruct the CT image

the portion of the xray beam transmitted through the patient and incident upon a single detector

the measurement of transmitted radiation made by an individual detector used to determine the attenuation occurring along a ray

• Region of Interest
• a user defined graphic outline that calculates the average Ct number of a given anatomic area

the 3D algorithm to provide a specific perspective to the construction of a 3D model

the ability of the CT detector to quickly measure xray and then recover before the next measurement

• a method of improving the temporal resolution of a MSCT during exams for the hear and mediastinum
• the data acquired during the diastole are used for image reconstruction allowing for reduction of motion artifact in the CT image

• is performed after the initial prospective reconstruction
• multiple retrospective reconstruction from raw data are possible with changes to DFOV, algorithms, image center

a incorrect ring of density on the reconstructed CT image resulting from detector malfunction