GE Vivid 7 User Manual
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Scanning Modes Vivid7/Vivid7 PRO Users Manual127 FC092326-03 Tissue Tracking controls Tissue Tracking assignable controls Tracking start The time after ECG R-peak when the integration should start. Tracking end The time after tracking start when the integration should end. Tracking scale Controls the color cut-off value of max displacement displayed. The chosen values is shown on the color bar when the assignable is activated. Invert Enables the color scheme assigned to positive and negative tissue velocities to be inverted. Invert is available in live and cine replay. Simultaneous Enables simultaneous display of 2D image and 2D image with Tissue Tracking color. Cineloop (in Freeze only) Starts cineloop acquisition. Color maps Displays a menu of color map options. Use the trackball to point a color map and press SELECT to activate a desired color map. Q-analysis (in Freeze only) Starts the Quantitative analysis application (see Chapter 7, ’Quantitative Analysis’ on page 233). 2D width (More menu) Controls the angular width of the 2D image sector. Alter native assignable controls Press ALT to access to the following modes: • Curved Anatomical M-Mode (see page 98) • Tissue Synchronization Imaging (see page 142)
Scanning Modes 128Vivid7/Vivid7 PRO Users Manual FC092326-03 • Tissue Tracking (see page 125) • Strain rate (see page 130) • Strain (see page 136) Tissue Tracking Soft menu controls Frame rate Controls the line density. When adjusting frame rate, there is a trade off between spatial and temporal resolution. Transparency Controls the degree of transparency of the Tissue Tracking color. Threshold Controls the level of greyscale intensity that is used as a threshold for color. Frequency Enables the adjustment of the transmission frequency to control the sensitivity or the level of penetration. Use Averaging con- trols with caution so as not to obscure significant diagnos- tic informationLateral Averaging Smooths the image by averaging collected data along the same horizontal line. An increase of the lateral averaging will reduce noise, but this will also reduce the lateral resolution. Radial Averaging Smooths the image by averaging collected data along the same radial line. An increase of the radial averaging will reduce noise, but this will also reduce the radial resolution. Power Controls the amount of acoustic power applied. When power is reduced the signal to noise ratio is reduced, so that the image may become noisier. Cine Compound (Freeze only) Calculates and displays cineloops generated from a temporal averaging of multiple consecutive heart cycles. The number of cycles averaged is controlled from the Soft menu rocker. The number of averaged cycles i displayed on the top left corner.
Scanning Modes Vivid7/Vivid7 PRO Users Manual129 FC092326-03 Using Tissue Tracking 1. From TVI Mode, press ALT on the control panel and press the TISSUE TRACKING assignable. 2. Adjust TRACKING START (assignable) close to the R-peak. 3. Adjust TRACKING END (assignable) near the T-wave. Optimizing Tissue Tracking • To reduce quantification noise (variance), the Nyquist limit should be as low as possible, without creating aliasing. To reduce the Nyquist limit, reduce the scale while in TVI. • To check for aliasing, freeze the loop and apply velocity trace (Press FREEZE and Q-ANALYSIS), see also Chapter 7, ’Quantitative Analysis’ on page 233). • The main use of Tissue Tracking is to map positive systolic displacements. This means that TRACKING START and TRACKING END assignables should be adjusted to pick out the systolic phase of the cardiac cycle: Adjust Tracking start close to the R-Peak. Adjust Tracking end near the T- wave. • Negative displacement can be mapped by pressing INVERT. TRACKING START and TRACKING END must then be adjusted to pick out the diastolic phase of the cardiac cycle. • The maximum displacement that is color-coded can be adjusted using the TRACKING SCALE assignable. If set too low, most of the wall will show the color indicating maximum displacement. If set too high, the maximum displacement color is never reached. • Tissue Tracking provides velocity information only in the beam direction. The apical view typically provides the best window since the beams are then approximately aligned to the longitudinal direction of the myocardium (except near the apex).
Scanning Modes 130Vivid7/Vivid7 PRO Users Manual FC092326-03 Strain rate Strain rate over view Figure 3-14: The Strain rate mode screen 1. Color sector marker 2. Status window 3. Soft menu 4. Strain sample size Controls marked with R are also available in freeze and cine replay.
Scanning Modes Vivid7/Vivid7 PRO Users Manual131 FC092326-03 Figure 3-15: The Strain rate mode controls on the front panel Strain rate calculates and color-codes the deformation per unit time i.e the speed at which the tissue deformation occurs. Strain rate is defined as the spatial gradient of velocity data. 1. Assignable keys: • 2D width • SRI scale R • Invert R • Simultaneous R • Color maps R • Q-Analysis (Freeze only) • Cineloop (Freeze only) ALT • Curved AMM R • AMM R • Tissue Tracking R • Strain rate R • Strain R 2. Zoom • Display zoom • HR zoom 3. Soft menu: • Frame rate • Strain Length • SRI Reject R • Compress R • Transparency R • Threshold R • Frequency • Lateral avg. • Radial avg. • Power • Cine compound R (Freeze only) 4. Freeze 5. TVI 6. 2D Controls marked with R are also available in freeze and cine replay 4 6 7 1 2 3 5
Scanning Modes 132Vivid7/Vivid7 PRO Users Manual FC092326-03 Strain rate controls Strain rate assignable controls 2D width Controls the angular width of the 2D image sector. SRI scale Defines the scale for the color coding of the strain rate. Invert Enables the color scheme assigned to strain rate to be inverted. Invert is available in live and cine replay. Simultaneous Enables simultaneous display of 2D image and 2D image with Strain rate color. Color maps Displays a menu of color map options. Use the trackball to point a color map and press SELECT to activate a desired color map. Q-analysis (in Freeze only) Starts the Quantitative analysis application (see Chapter 7, ’Quantitative Analysis’ on page 233). Cineloop (in Freeze only) Starts cineloop acquisition. Alter native assignable controls Press ALT to access to the following modes: • Curved Anatomical M-Mode (see page 98) • Tissue Synchronization Imaging (see page 142) • Tissue Tracking (see page 125) • Strain rate (see page 130) • Strain (see page 136)
Scanning Modes Vivid7/Vivid7 PRO Users Manual133 FC092326-03 Strain rate Soft menu controls Frame rate Controls the line density. When adjusting frame rate, there is a trade off between spatial and temporal resolution. Strain length Determines the strain sample volume size. SRI Reject Adjust the cut-off level of the low tissue velocity to be discarded when generating the color image. Rejected values are displayed in green. Compress Controls the amount of color compression. The color bar is adjusted accordingly. Transparency Control the degree of transparency of the strain rate color. Threshold Controls the level of greyscale intensity that is used as threshold for color. Frequency Enables the adjustment of the transmission frequency to control the sensitivity or the level of penetration. Lateral Averaging Smooths the image by averaging collected data along the same horizontal line. An increase of the lateral averaging will reduce noise, but this will also reduce the lateral resolution. Use Averaging con- trols with caution so as not to obscure significant diagnos- tic information.Radial Averaging Smooths the image by averaging collected data along the same radial line. An increase of the radial averaging will reduce noise, but this will also reduce the radial resolution. Power Controls the amount of acoustic power applied. When power is reduced the signal to noise ratio is reduced, so that the image may become noisier.
Scanning Modes 134Vivid7/Vivid7 PRO Users Manual FC092326-03 Cine Compound (Freeze only) Calculates and displays cineloops generated from a temporal averaging of multiple consecutive heart cycles. The number of cycles averaged is controlled from the Soft menu rocker. The number of averaged cycles i displayed on the top left corner.
Scanning Modes Vivid7/Vivid7 PRO Users Manual135 FC092326-03 Using Strain rate 1. From TVI Mode, press ALT on the control panel and press STRAIN RATE. Optimizing Strain rate • To reduce quantification noise (variance), the Nyquist limit should be as low as possible, without creating aliasing. To reduce the Nyquist limit, reduce the scale while in TVI. • To check for aliasing, freeze the loop and apply velocity trace (Press FREEZE and Q-ANALYSIS), see also Chapter 7, ’Quantitative Analysis’ on page 233). • Strain rate provides velocity information only in the beam direction. The apical view typically provides the best window since the beams are then approximately aligned to the longitudinal direction of the myocardium (except near the apex). • There is a trade-off between noise and spatial resolution controlled by the Strain length. To minimize noise the Strain length should be maximized. • The maximum Strain rate that is color-coded can be adjusted using the SRI SCALE assignable. If set too low, most of the wall will show the color indicating maximum Strain rate. If set too high, the maximum Strain rate color is never reached.
Scanning Modes 136Vivid7/Vivid7 PRO Users Manual FC092326-03 Strain Strain over view Figure 3-16: The Strain mode screen 1. Color sector marker 2. Strain color bar 3. Status window 4. Soft menu 5. Strain start and end markers 6. Strain start and end from R-peak and Strain sample size Controls marked with R are also available in freeze and cine replay.