Advanced analysis

Signal strength

Use this command to create a new trace, calculated from the signal strength of the selection, or all of the currently active Doppler spectrum.

Power contour

Use this command to calculate ten power contours from the currently active Doppler spectrum.

Ten new traces will be created.

This calculation may take some time for long traces.

Level contour

Use this command to calculate and create any number of contours from the currently active Doppler spectrum.

This calculation may take some time for very long traces.

Pulsatility Index

Use this function to calculate and create a Pulsatility Index trace from a CBV trace. This is calculated using the following formula:

Pulsatility Index = ( Peak Systolic - Minimum Diastolic ) / Mean CBV

The traces created during the calculation are left in place to help identify any artifacts. These traces may be deleted if desired.

The mean is created automatically using the Remove Pulse function.

For the detection of the peak systolic and minimum diastolic, you will be prompted for a Window size. This is the number of data points before and after the current point, which must be all lower or all higher than the current point, in order for that point is considered a peak or a minimum.

Resistance Index

Create and calculate the resistance index for the current selection of the currently line active trace.

Resistance Index = ( Peak systolic - minimum diastolic) / ( Peaksystolic )

The systolic and diastolic traces created during the calculations are left to help identify any artifacts. These can be deleted if desired.

Select Edit, Smooth Selection, to smooth the resulting Resistance Index trace if desired.

Calculate Power Spectrum

Use this function to calculate a 256 point colour coded power spectrum from the currently active line trace.

Creates 1 PSD point for each block of 512 data points in the sourcetrace.

Note the DC value is not saved, since WCAM1 saves the bandwidth in the 0 Hz bin.