Displays and Image Processing Flashcards

Question

read magnification

Answer 1

``` occurs AFTER image data is stored in scan converter (post processing) uses old data larger pixel size same amount of pixels as original ROI unchanged resolution ```

Answer 2

``` applied before storage in scan converter (preprocessing) uses new data identical pixel size more pixels than in the original ROI improved spatial and temporal resolution ```

Answer 3

coded excitation

Answer 4

contrast, axial, and spatial

Answer 5

method of using sonographic info from several imaging angles to produce a single image o Frames are overlapped / compounded o Reduces speckle and minimizes shadowing artifacts o Limitations – reduced frame rates, reduced temporal resolution o Uses electronic steering o Available only with phased array transducers

Answer 6

reduces speckle artifact and noise in US images o All reflected sound pulses contain a large range of frequencies, with frequency compounding the reflected signal is divided into sub-bands of limited frequencies and an image is created from each sub-band o The images from each sub-band are then combined into a single image

Answer 7

makes pictures look sharper by emphasizing sharp edge boundaries in the image, such as the reflecting surface between two media with different gray scale levels o Works by increasing the contrast in the area around the edge

Answer 8

also called persistence or temporal averaging o Image processing technique that continues to display information from older images o Several previous frames are superimposed on the most current frame o Produces a smoother image with reduced noise, higher signal to noise ratio, and improved image quality o Limitations – reduction in displayed frame rate which reduces temporal resolution o Persistence/temporal compounding is the most effective with slowly moving structures and less useful in rapid moving structures such as echo because rapid motion cannot be observed acuratelly

Answer 9

2D images created from multiple ultrasound pulses into the body, with sector shaped images the scan lines separate at increasing depths, gaps/missing data exist between the scan lines and interpolation is a method of constructing new simulated data points to fill in the gaps o Goal is to fill in the gaps of missing data in a way that cannot be detected by the observer o Predicts grayscale levels of missing data o A form of preprocessing o As the line density increases with fill-in, the spatial resolution increases

Answer 10

a dynamic technique that produces images from sound reflections in an entirely new way o Images are related to the mechanical properties of tissue o Theory of elastography – tissues will deform differently following the application of a force o Estimates of tissue stiffness are obtained o Stiffness data and ultrasound reflections are combined into images called elastograms o Can be combined with anatomical images and doppler to add to the diagnostic value of the ultrasound exam o Can differentiate between benign and malignant tumors

Answer 11

picture archiving and communication system o Describes the digital ultrasound laboratory in which images and medical info are digitized and stored on a large computer network o 3 major advantages 1. Virtually instant access to archived studies 2. No degradation of data 3. Electronic transmit images and reports to remote sites o Computer hard drives are the primary digital storage devices used in PACs

Answer 12

digital imaging and computers in medicine o A set of rules, or protocols, that allows imaging systems to share information on a network o Assures current imaging modalities can communicate o Guarantees that all devices developed in the future will easily attach to the PACs network