The Knoll/MIDUS™ System

The 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.