The UroMetrics Knoll/MIDUS Ultrasound System is an office-based, bi-directional, continuous wave Doppler, ultrasound system with spectral analysis designed to measure deep cavernous artery blood velocities. Blood velocity is determined by detecting the Doppler shifts of an 8 MHz ultrasound signal supplied by separate transducers for identical processing of information independent of blood flow direction. Proprietary software converts this raw data into a usable waveform. This provides information about the Doppler shift in frequencies as a frequency over time diagram with intensities being represented by varying shades of gray.

Unlike Duplex Doppler Ultrasonography performed in the hospital, the Knoll/ MIDUS Ultrasound System is designed as an office-based system featuring proprietary SureAngle™ Transducer Probes and a Gold Guard™ Cradle. The probes and cradle maintain a 60° angle that ensures repeatable measurements during testing.

Typical Results

Various studies have referenced the following parameters as normal for cavernous artery velocities using ultrasound techniques:

Peak Systolic Velocity 0.30 meters/sec. (30 cm/sec)
End Diastolic Velocity 0.05 meters/sec (5 cm/sec)
Resistance Index 0.70

Patients with a peak systolic velocity below 30 cm/sec are considered to be afflicted with arterial insufficiency.

Patients with an end diastolic velocity above 5 cm/sec are thought to be suffering from veno-occlusive dysfunction (venous leakage).

Those with both a decreased peak systolic and elevated end diastolic velocity are considered to have a mixture of arterial insufficiency and venous leakage.

The Resistance Index is a calculation that is useful to confirm the severity of a veno-occlusive dysfunction. The result of this calculation is inversely proportional to the degree of venous leakage. In other words, as the Resistance Index decreases, the venous leakage increases.

Clinical Studies and References

Knoll, L.D., Abrams, J.H. Evaluation of penile ultrasonic velocitometry versus penile duplex ultrasonography to assess penile arterial hemodynamics. Urology, 1998; 51(1): 89-93.

Lue, T.F., Hricak, H., Marich, K.W., et al. Vasculogenic impotence evaluated by high-resolution ultrasonography and pulsed Doppler analysis. Radiology, 1985; 155: 777-81.

Lue, T.F., Mueller, S.C., Jow, Y.R., Hwang, T. Functional evaluation of penile arteries with duplex ultrasound in vasodilator induced erection. Urol. Clin. North Am. 1989; 16: 799-806.

For Tech. & Sales Support
Contact John Murphy at
952-544-1080
e-mail: jpmurphy@mn.rr.com