1- dimensional array (1D array)
A transducer array in which the transducer elements are arranged in a single row.
Related terms: 1.25-dimensional array, 1.5-dimensional array, 1.75-dimensional array, row-column array, 2-dimensional array, matrix array.
1.25-dimensional array (1.25D array)
A transducer array in which the addressable elements are arranged in more than one symmetric row, that allows better focusing than a 1-dimensional array but not as complex as a 1.5-dimensional array.
Related terms: 1-dimensional array, 1.5-dimensional array, 1.75-dimensional array, row-column array, 2-dimensional array, matrix array.
1.5-dimensional array (1.5D array)
A transducer array in which the addressable elements are arranged in more than 2 symmetric rows, with corresponding elements in the rows connected together in pairs. This is most often done to enable electronic focusing and dynamic aperture control to minimize slice thickness over the imaged field. In 1.5-dimensional arrays, the electrical excitation pattern is symmetric above and below the center row of elements, so no beam steering can occur, as would be needed for 3-dimensional scanning.
Related terms: 1-dimensional array, 1.25-dimensional array, 1.75-dimensional array, row-column array, 2-dimensional array, matrix array.
1.5 harmonic contrast-enhanced sonography
A contrast-enhanced modality in which images are obtained in a frequency band intermediate between the fundamental mode and second harmonic mode and whose center frequency is higher than the fundamental by a factor of 3/2.
Related terms: Ultraharmonic imaging
1.75-dimensional array (1.75D array)
A transducer array in which the elements are arranged in 4 or more individually addressable rows to enable electronic focusing and dynamic aperture in the elevational direction as well as to allow limited beam steering in the elevational direction. Beam steering is possible because elements may be excited individually, allowing for an asymmetric excitation pattern between rows. There usually is not a sufficient number of rows, however, to allow beam steering over a wide angular range in the elevational direction, as would be needed for
3-dimensional scanning.
Related terms: 1-dimensional linear array, 1.25 dimensional array, 1.5-dimensional array, row-column array, 2-dimensional array, matrix array.
2- dimensional array (2D array)
A multiple-element transducer array that can be configured to control the characteristics and direction of an acoustic beam usually in 2 orthogonal scan planes.
Related terms: 1-dimensional linear array, 1.25 dimensional array, 1.5-dimensional array, 1.75-dimensional array, row-column array, matrix array.
2-dimensional echocardiography (2D echocardiography)
Two-dimensional B-mode imaging of the heart.
2-dimensional imaging
See B-mode imaging
3-dimensional echocardiography (3D echocardiography)
Three-dimensional ultrasound imaging of the heart.
3-dimensional acquisition (3D acquisition)
Scanning methods used to acquire 3-dimensional data. Includes freehand, position-sensed freehand, mechanically swept, and electronically swept (2-dimensional array).
Related terms: electronically swept scanning (2-dimensional array), freehand scanning, mechanically swept scanning, position-sensed freehand scanning
3-dimensional imaging (3D imaging)
An ultrasound technique in which the desired structure can be viewed in 3 dimensions.
Related terms: 3-dimensional acquisition, electronically swept imaging scanning (3-dimensional), freehand scanning, mechanically swept scanning, position-sensed freehand scanning
4-dimensional imaging (4D imaging)
An ultrasound technique in which the desired structure can be viewed in 4 dimensions (ie, 3-dimensional imaging in time). This technique allows the viewing of fetal, heart, and other anatomic movements in 3 dimensions.
Related term: 3-dimensional imaging