Philips epiq 7, User Manual

Page: 58 / 318

Control Effects
Controls Affecting the Indices
As various system controls are adjusted, the TI and MI values may change. This will be most
apparent as the output power control is adjusted; but other system controls affect the
on
‑
screen output values.
Power
The output power control affects the system acoustic output. Two real
‑
time output values are
on the display: TI and MI. They change as the system responds to power-control adjustments.
In combined modes, such as simultaneous Color, 2D, and PW Doppler, the individual modes
each add to the total TI. One mode will be the dominant contributor to this total. The displayed
MI will be from the mode with the largest MI value.
2D Controls
• Sector Width: Narrowing the sector angle may increase frame rate. This action will increase
the TI. Pulser voltage may be automatically adjusted down with software controls to keep
the TI below the system maximums. A decrease in pulser voltage will decrease MI.
• Zoom: Increasing the zoom magnification by pressing Zoom may increase frame rate. This
action will increase the TI. The number of focal zones may also increase automatically to
improve resolution. This action may change the MI, because the peak MI can occur at a
different depth.
• Number of Focal Zones: More focal zones may change both the TI and MI by changing
frame rate or focal depth automatically. Lower frame rates decrease the TI. MI displayed
will correspond to the zone with the largest MI value.
• Focus: Changing the focal depth will change MI. Generally, higher MI values will occur when
the focal depth is near the natural focus of the transducer.
Color and Power Controls
• Flow Opt: Increasing the color sensitivity with the Flow Opt control may increase the TI.
More time is spent scanning the color image. Color pulses are the dominant pulse type in
this mode.
Safety Biological Safety
58 EPIQ 7 User Manual 4535 617 25341