CT image processing & Display
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| The amount of the xray beam that is reduced by absorption as it passes through an object | show 🗑
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| show | Hounsfield Units
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| Hounsfield units are also called... | show 🗑
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| show | detectors
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| Hounsfield units are directly related to.... | show 🗑
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| finite set of steps performed to solve a problem | show 🗑
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| The process of using RAW DATA to create an image | show 🗑
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| show | interpolation
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| Data from detectors that have NOT been assigned a hounsfield unit | show 🗑
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| Processed raw data; each pixel within the data has been assigned a hounsfield unit | show 🗑
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| show | Processed data
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| show | image data, raw data takes up too much space but when we store image data we cannot do anything with it when it goes in pacs
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| To take all of the multiple data projections collected DURING scanning, compute and assign a CT number to each pixel in the digital image; process of using RAW DATA to create an image | show 🗑
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| The time from the end of scanning to image display | show 🗑
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| image that is produced during scanning | show 🗑
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| Taking the raw data after scanning is over and at a later time using it to create a new image | show 🗑
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| The path the xray beam takes from the tube to the detector | show 🗑
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| show | Ray sum
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| show | View
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| Accounting for the attenuation properties of each ray sum and correlation it to a position of the ray | show 🗑
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| show | Back projection
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| show | Filtered back projection
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| show | Convolution
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| show | Standard, smoothing, edge enhancement, bone, detail
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| This allows us to use less does, but get granny images but then allows us to reconstruct the image as if we gave the patient 100% of the radiation | show 🗑
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| show | before
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| show | pitch
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| show | Scan field of view (SFOV)
Display field of view (DFOV)
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| what FOV is the area within the gantry that the raw data will be collected; determines the number of detectors collecting data for a particular scan | show 🗑
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| What FOV is the region of interest in the resulting images; always equal to or smaller then the SFOV | show 🗑
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| show | true
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| show | the field in which you are interested in
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| Manipulating both the raw AND image data AFTER the scanning has taken place | show 🗑
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| When raw data is manipulated to create pixels that are then used to create an image | show 🗑
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| Image that us produced during scanning | show 🗑
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| Taking the raw data after scanning is over and at a later time using it to create a new image | show 🗑
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| show | image reformation (image rendering)
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| show | Image rendering
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| show | identical DFOV, image center, gantry tilt, contiguous, no patient motion
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| Quantitative measurements = | show 🗑
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| show | Multi-planar reformation (MPR)
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| This represents the entire scan volume in only one image | show 🗑
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| Includes only information from the surface of a defined tissue threshold | show 🗑
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| Every voxel is used; the sum of the voxels along a line are assigned an opacity value to form the final image | show 🗑
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| This is a software program that will create a 2D image from a 3D data set; utilized commonly in angiography imaging, Used to separate superimposed vessels. This picks out the highest values of voxels | show 🗑
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| Specialized software can quantitively measure images and obtain information about volume, distance, and diameter | show 🗑
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| show | CT number
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| This is the standard scale of CT numbers. (what are CT numbers also called) | show 🗑
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| show | 0
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| air= | show 🗑
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| bone= | show 🗑
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| When air shows up on a CT image it looks... | show 🗑
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| when bone shows up on a CT image it looks | show 🗑
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| show | Yes, with contrast
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| Why are HU/CT numbers useful? | show 🗑
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| show | Windowing
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| This is the range of CT numbers | show 🗑
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| show | Increases contrast, short scale, black and white
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| show | decreases contrast, long scale, lots of grays
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| show | Window level
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| Hounsfield measurements are the result of the.... | show 🗑
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| Standard deviation is | show 🗑
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| This is a display function that defines an area of an image | show 🗑
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| Used to measure distance of structures | show 🗑
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| show | Image annotation
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| show | Reference image
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| For image magnification you only need what information? | show 🗑
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| show | Raw data
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| Continuous acquisition scanning WITHOUT TABLE MOVEMENT; important when observing arterial contrast enhancement | show 🗑
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| Spaital resolution in CT refers to the... | show 🗑
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| show | Spacial resolution
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| show | contrast resolution
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| When you have good spatial resolution, you have ______ contrast resolution | show 🗑
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| When you have good contrast resolution, you have _____ spatial resolution | show 🗑
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| When you have a big matrix like 512x512, this will result in better____ | show 🗑
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| show | to demonstrate small changes in tissue contrast
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| When you have a larger slice thickness and a higher mAs, this improves what | show 🗑
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| The fluxuation of CT numbers from point to point in an image for a scan is called | show 🗑
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| show | Noise
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| Contrast resolution, spatial resolution and noise all affect the change of ___ | show 🗑
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| Increasing slice thickness and ________ spacial resolution | show 🗑
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| show | MA, KVp
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| Display FOV and matrix affects what | show 🗑
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| show | voxel size
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| show | zero
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| This is a comparison of an image to the actual object | show 🗑
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| Imaging parameters that affect quality are... (7). These are things that WE control to make an image look good | show 🗑
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| show | MAS
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| show | MA
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| show | Time
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| show | electrons
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| This is the intensity (penetrating power) of the xray beam | show 🗑
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| show | electrons
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| show | Slice thickness
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| show | SFOV
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| show | False
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| This aids un reconstructing optimal images by tissue types; filter to enhance certain tissue characteristics and applied to raw data | show 🗑
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| This is the relationship between slice thickness and table travel per rotation | show 🗑
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| show | Spatial resolution, Contrast resolution, Noise and dose
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| Spatial resolution is also referred to as ______ | show 🗑
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| This is very close strips of metal close together | show 🗑
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| How often an object will fit into a given space | show 🗑
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| show | low
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| Small objects have a _____ spatial frequency | show 🗑
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| CT has ____ spatial frequency | show 🗑
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| What are the 6 factors of spatial resolution | show 🗑
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| show | Focal spot size
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| This is able to distinguish between similar tissues | show 🗑
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| show | photons, pixels
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| show | Increase
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| show | Contrast resolution, noise
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| show | dose
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| higher Ma= higher ___ | show 🗑
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| Increase in Kvp, increasaes the number of photons = ______ dose | show 🗑
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| show | increase
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| show | Temporal resolution
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| show | Gantry speed, number of detector channels, speed that the system can record changing signals
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| show | Quality control programs
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| in a CT quality control phantom, what does the first line stand for? | show 🗑
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| in a CT quality control phantom, what does the second line stand for? | show 🗑
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| in a CT quality control phantom, what does the third line stand for? | show 🗑
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| in a CT quality control phantom, what does the fourth line stand for? | show 🗑
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| show | CT tech, service engineer and physicist
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| show | yes
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| Why are QAs necessary? (4) | show 🗑
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| show | Spatial resolution and contrast resolution
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| show | spatial
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| _____ resolution uses contrast resolution phantoms with objects varying size; 0.5% of a sum object;performed monthly | show 🗑
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| show | Slice thickness accuracy
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| show | 1
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| show | .5
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| show | laser light accuracy
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| This assesses the relationship between CT numbers and linear attenuation values; measured semiannually | show 🗑
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| A water phantom is used; done on a weekly basis | show 🗑
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| show | 10
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| The more _____ the less contrast resolution | show 🗑
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