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3 Stooges
3 Musketeers
3 Amigos
3 Blind Mice
3's a Crowd
100
This type of imaging is currently considered to be an important imaging modality in disease diagnoses despite several limitations including: the need of the diagnostician to mentally transform images into a 3-D impression which is a slow and subject process, using an idealized shape in order to measure volume which is considered inaccurate, not suited to monitoring or planning procedures as it is difficult to use this imaging to determine a particular location, and can be difficult to change orientation of the transducer into the best plane for accurate imaging.
What is Ultrasonography(2D)
100
This type of imaging seeks to lessen the variability seen in past techniques and has been under development by altering the positioning, and method of acquisition. It works to incorporate the transducer positioning into the two dimensional image in order to reconstruct a more complete image used for disease diagnosis and treatment.
Three-Dimensional Imaging
100
This technique was first developed at Duke university in 1987. It seeks to improve the limitations seen by two-dimensional ultrasounds and improve the ability to more accurately visualize many diseases
What is Three-Dimensional Ultrasound
100
Probe using ultrasound waves into tissue which reflects and echoes as it reaches tissue and is able to be used in order to create an image.
What is Transducer
100
Mechanical localizer motion, which has been successful in prostate imaging.
What is Tilt Motion
200
Acquisition method based on a one dimensional transducer which remains stationary and utilizes electronic scanning of a phased array of elements in order to produce 3D images by sweeping out pyramidal volumes. These echoes allow multiple planes to be displayed from the volume. Limitations include high cost, low yield due to small transducer and it best suited to imaging of smaller volumes such as the heart
What is Two-Dimensional Arrays
200
This acquisition method uses one dimensional arrays which are manually or mechanically manipulated in order to record a series of images in 2 dimensions. This allows the position to be relatively determined. Limitations include that they can be cumbersome and need special equipment. Three types of motion can be used in this acquisition method
What is Mechanical Localizers
200
Acquisition method where the transducer is able to move more freely while recording positional information. This can decrease the risk of mistakes or inaccuracies. The risk of gaps is minimized as a constant scanning velocity. There are four position sensing techniques in this method.
What is Freehand Scanning with Position Information
200
Acquisition method, which does not use a sensing device but instead, uses an assumption that the scanning geometry is pre-defined. This method requires that the transducers path be at either a constant angular or linear velocity in order to produce an accurate image. However, as it is based on assumption it is not suited to determining exact distance, volume or area.
What is Freehand Scanning without position sensing
200
Multiplanar reformatting can use this shape to represent the boundaries of the reconstructed volume
What is Polyhedron
300
This reconstruction technique uses a certain structure to create boundaries, which can then be associated and used to reconstruct a 3D surface model. This approach can be advantageous as it simplifies the image into surfaces in addition to being capable of increasing contrast between anatomies artificially. However, as simplification occurs, key details can be lost and this approach can be very slow and complicated in images with low contrast.
What is Feature-based Reconstruction
300
This reconstruction places pixels on a volume in 3 dimensions. This methodology is advantageous as it does not disregard details and hence the original images can be revisited. Limitations can occur when sampling is done improperly and interpolation misrepresents the true anatomy of the structure
What is Voxel-based Reconstruction
300
Most common form of rendering it simplifies structures into surfaces using segmentation to initially determine the structure under scrutiny. After suitable boundaries are selected, they become represented as a frame or mesh
What is Surface-Based Rendering
300
Rendering technique which uses an algorithm or a voxel based technique which can use one of two approaches to display a three dimensional image. Advantageous as operator may rotate the surfaces or structure and manipulate them into the optimum positioning
What is Multiplanar Reformatting
300
This rendering technique projects a two dimensional image. Generally, the voxels containing either the minimum or maximum intensity are displayed in order to project an image. Alternatively opacity rendering approach may be used. Limitations include difficulties with interpretation and computationally expensive ray technologies being used.
What is Volume Rendering
400
Type of mechanical localizer motion in which the images in two dimensions are parallel. These images are at a known distance from eachother and thus an advantage is a shorter reconstruction time. However, the three dimensional image’s resolution is not uniform and thus is the lowest resolution approach
What is Linear Motion
400
Type of mechanical localizer motion using an axis parallel to the transducer’s face and can be accomplished by an external or internal probing approach. The transducer is stationary in the external approach while internal use dictates the use of a rotation of the transducer on a axis, which creates images in the geometry of a fan. This is advantageous as the transducer itself is small in size, and with the correct angles used it can have a shortened scanning period.
What is Tilt Motion
400
Type of mechanical localizer motion, which involves the transducers rotation to an axis perpendicular to the array of the transducer. The two-dimensional images created by this are conical in volume. Due to this arrangement, resolution in these images is higher at a closer proximity to the transducer and degrades as the distance increases
What is Rotational Motion
400
Freehand scanning technique used to sense position by mounting the transducer on a mechanical system equipped with potentiometers. Thus, the angulation and position can be determined relatively from the 2 dimensional images.
What is Articulated Arms
400
Rendering technique used successfully in the rendering of echocardiographic and obstetrical images
What is Surface-based Rendering
500
Freehand scanning technique using magnetic field sensors created by a transmitter and a small receiver in order to determine strength of the field. Three coils are used which allow the position of the transducer and angulation to be determined. Limitations include interference by electromagnetic and distortion of the field by metals and too low sampling rates can introduce error.
What is Magnetic Field Sensors
500
Freehand scanning technique, which uses acoustic ranging. Spark gaps are utilized on the transducer and microphones. The transducer is shifted as sound pulses are received in order to determine both position and orientation
What is Acoustic Freehand Three-Dimensional Scanning
500
Freehand scanning technique using reflected spatial energy. The acquired images must be separated into smaller sections in order to determine a pattern and ultimately displacement vectors which are used to analyze to determine relative positioning and the orientation of images, which are adjacent.
What is Speckle Decorrelation
500
Multiplanar reformatting can use this shape to represent the boundaries of the reconstructed volume.
What is Polyhedron
500
Mechanical localizer motion, which has been successful in both endovaginal imaging and transrectal prostate imaging
What is Rotational Motion