quiz 4
Proper patient preparation is not important for the success of virtual colonoscopy.
False
Slice imaging is the most complex of all 3D imaging.
False
The CT number for water is +1000.
False
The development of computed tomographic angiography and 3D imaging has not proved effective in the evaluation of cerebral aneurysms and arteriovenous malformations.
False
The measurement of the total X-ray absorption of a particular ray is defined as a view.
False
The range of CT numbers is the WL.
False
The results of preprocessing are referred to as image data.
False
Windowing does not make use of the CT numbers.
False
Which algorithm belongs to the class of analytical algorithms for CT?
Filtered back-projection (FBP)
Which of the following belongs to the class of nonlinear image manipulation techniques?
Gray-scale manipulation
Which algorithm provides a valuable perspective in defining lesions for surgical planning or detecting subtle small airway diseases?
Minimum intensity projection
Which of the following basic visualization tools allows for the mean and standard deviation within a given ROI?
ROI statistics
Anatomy missed as a result of patient respiration can have what type of appearance on the final 3D image?
Stairstep artifact
Which is an example of a 3D rendering algorithm?
Surface rendering (SR)
Volume rendering produces 3D images that have a better image quality and provide more information compared with SR.
True
Voxel-based processing makes determinations about each voxel and decides to what degree each should contribute to the final 3D image.
True
Windowing is the most common image processing technique in CT.
True
What technique is used to virtually unroll, slice open, and display a 3D model of the colon?
Virtual dissection
Which of the following is a technique whereby 3D surfaces are extracted from a volume or whereby voxels are extracted from a volume into another 3D segmented region?
Volume extraction
Which type of 3D imaging approach produces a true 3D visualization?
Volume imaging
Which of the following determines the maximum number of gray shades to be displayed on the television monitor?
Window width (WW)
Which of the following removes the classical star pattern artifact of the back-projection algorithm?
FBP
In the scene (xyz) coordinate system, the axes are positioned at __________ angles.
90-degree
Which of the following refers to a defined set of instructions for solving a problem?
Algorithm
An examination of the abdomen has a WW of 400 and a WL of 0. Which of the following is true given these settings?
All structures between -200 and 200 will spread through the gray scale
MinIP is an algorithm that only the tissues with the greatest attenuation will be displayed for viewing by an observer.
False
What is the first step in virtual endoscopy imaging?
Careful selection of scan parameters
Which advanced tool in CT allows users to view a large set of images very quickly?
Cine visualization
Which of the following describes the beam that diverges from the X-ray tube to the outer edges of the detectors?
Cone beam
One industry standard in data transfer and connectivity is:
Digital Imaging and Communications in Medicine (DICOM).
Which of the following algorithms is most commonly used in the state-of-the-art CT scanners?
FBP
Which is a mathematical technique used to estimate the value of a function from known values on either side of the function?
Interpolation
Which of the following will allow the user to interactively visualize, manipulate, and measure large three-dimensional objects on general-purpose workstations?
Three-dimensional algorithms
A large WW means a long gray scale.
True
A large cone beam will result in cone-beam artifacts.
True
Most experts agree that SR is not best suited for use in CTVR imaging.
True
Semiautomatic segmentation allows the operator to select objects to be included in the VR image data set through the use of windowing.
True
The signals that leave the CT detectors are subject to preprocessing.
True
Volume rendering provides multiple benefits for virtual CT endoscopy except its ability to:
combine SR techniques.
All of the following describe basic problems with the back-projection algorithm except:
compares assumptions with measured values.
Virtual endoscopy allows the viewer to "fly through" each of these structures except:
cortical bone.
The creation of the simulated 3D image from data collected from the object space is called:
rendering
As the WW increases, picture contrast:
decreases
Preprocessing involves the use of all of the following except:
delineation.
The generation of a 3D object by using computer software is called:
modeling.
The fourth dimension involved in 4D angiography is ____________.
opacity
A set of ray sums is referred to as a:
projection
The most familiar coordinate system is the:
scene coordinate system.
Algorithms for sliding thin slabs (STS) include all of the following except:
total intensity projection.
Virtual endoscopy includes all of the following applications except:
virtual arthroscopy.
