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27 Cards in this Set
- Front
- Back
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What is the purpose of 3D imaging?
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To use vast amounts of data collected from the patient to provide both quantitative and quality information.
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What is qualitative information?
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Qualitative information is used to to compare how observers perform on a specific task to demostrate the diagnostic value of 3D.
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What is quantitative information?
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Quantitative information is used to assess three elemens of the technique: precision, accuracy, and efficiency.
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What are the 4 coordinate systems that relate to the CT Scanner in regards to 3D images?
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1. scanner coordinate system (abc)
2. display coordinate system (rst) 3. object coordinate system (www) 4. scene coordinate system (xyz) |
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What is the scanner coordinate system (abc)?
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The scanner coordinate system (abc)
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What is the scene or Cartesian coordinate system (xyz)?
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the x, y, and z axises are positioned at right angles to one another (orthogonal)
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What is orthogonal?
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Where the x, y, and z axises are positioned at right angles to one another.
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What is does the x axis stand for?
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The width of an object is described by the x axis.
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What is does the y axis stand for?
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The height of an object is described by the y axis.
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What is does the z axis stand for?
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The z axis describes the demention of an object isand adds perspective realism to the image.
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What does a coordinate system do?
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It allows descriptions of an object be measuring distances from point of intersection. Or the zero point.
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What does the term scene stand for?
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-Multidemential images, rectanglular array with assigned values.
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What is scene domain?
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-Anatomic region represented by the scene.
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What is scene intensity?
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The values assigned to the voxels in a scene
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What is modeling in regards to 3D imaging?
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The generation of a 3D object using computer software is called modeling. It uses mathmatics to describe physical properties.
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What is rendering?
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Rendering is the final step in the process of generating a 3D object. It involves the creation of the simulated 3D image, a computer program that converts anatomic data collected from the patient into the 3D image seen.
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What are the two types of rendering used in radiology?
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1. Surface rendering- only uses contour data from the set
2. Volume rendering- uses the entire data set. |
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What are the three classes of 3D imaging approaches?
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1. slice imaging-(MPR) saggital and coronal
2. protective imaging- volume rendering (2.5D)not a true 3D 3. volume imaging-true 3D visualization mode |
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What are the four steps needed to create a 3D image?
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1.Data acquisition.
2.Creation of 3D space or scene space 3. Processing for 3D image display 4. 3D image display |
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What is voxel based processing?
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Voxel based processing determines which voxels will make up the the final 3D display. MPRs
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What is object based processing?
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Object based processing uses voxel information to transform the images into collections of objects, which undergo several processing methods.
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What are the four steps that change a object model into a 3D image?
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1. Segmentation
2. Thresholding 3. Object delineation 4. Rendering |
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What is Segmentation in regards to 3D imaging?
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Segmentation is a processing technique used to identify the structure of interest in a given scene. It determines which voxels to keep and which are not needed.
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What is Thresholding in regards to 3D imaging?
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Thresholding is a method of classifying the different types of tissues and assigning CT numbers to them.
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What is Object delineation in regards to 3D imaging
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Object delineation is portraying an object by drawing it. It involves boundry and volume extraction and detection methods.
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What is surface rendering?
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Also called shaded surface display (SSD), it uses the internal representation of surfaces and then lights them according to standard protocols.
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What is MIP?
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Maximum Intensity Projection- originated in MR for MRAs. It does not require sophisitcated computer hardware because it uses less than 10% of the collected data
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