Moderator – Dr. Ak. Kaku Singh

Presenter – Dr. Vijayendra 24-09-13

Investigations for diagnosing ED

Basic labs

Specialized evaluation and testing

1. Vascular Evaluation

2. Audiovisual Sexual Stimulation (AVSS)

3. Neurophysiologic

Vascular Evaluation

1. Combined Intracavernous Injection and Stimulation

2. Duplex Ultrasonography (Gray Scale or Color Coded)Second-line evaluation

The most reliable and least invasive diagnostic modality for assessing ED.

The test adds an imaging dimension and a quantification component to the evaluation of blood flow in the penis distinct from first-line evaluation (CIIS), which relies on the assessor’s judgment alone.

The technique consists of high-resolution (7 to 10 MHz) real-time ultrasonography and color pulsed Doppler, which serves to visualize the dorsal and cavernous arteries selectively and to perform hemodynamic blood flow analysis (Lue et al, 1989)

Red - direction toward the probe

Blue - designating direction away from the probe

Flow velocities are measured at base -line before injection and commonly every 5 minutes afterwards up to 20 minutes.

Cavernous arterial diameters may also be measured.

Standard pattern of Doppler waveforms (monophasic) occurs with hemodynamic changes in corporeal pressure during progression to normal full erection.

In the filling phase when sinusoidal resistance is low (within 5 minutes after vasodilator injection), the waveform increases in size consistent with high forward flow during both systole and diastole.

As intracavernous pressure ,diastolic velocities

Artist’s conception of the changes in diameter and flow waveform in the cavernous arteries induced by intracavernous injection of prostaglandin E1 in a potent young man as demonstratedby duplex ultrasound. Forceful concentric pulsations areparticularly noticeable during full erection.

With full erection, the systolic waveforms sharply peak and may be slightly less than during full tumescence.

At maximal rigidity, when intracavernous pressure exceeds systemic diastolic BP , diastolic flow may be Zero.

The sonographic color pattern of the cavernous artery may demonstrate an impressive shift from red to blue in association with the reversal of diastolic flow.

PSV (peak systolic velocity) of cavernous arteries after pharmacostimulation ranges from 35 cm/sec to 47 cm/secin normal subjects.

A cut point at 25 cm/sec had a sensitivity of 100% and a specificity of 95% in patients with abnormal pudendalarteriography (Quam et al, 1989).

Diameter changes of the cavernous artery after vasodilator injection were found to increase less than 75% and rarely exceed 0.7 mm in patients with severe vascular ED.

Artist’s conception of the changes in diameter and flow waveform in the cavernous arteries induced by intracavernous injection of prostaglandin E1 in a potent young man as demonstratedby duplex ultrasound. Forceful concentric pulsations areparticularly noticeable during full erection.

Color duplex ultrasound in a longitudinal view

Disadvantages-

Anatomic variations

Early cavernous arterial branching

Presence of multiple such branches

The presence of distal arterial perforators extending from the dorsal or spongiosal arteries also may alter the measurement of cavernous arterial blood flow velocity.

The findings of dissimilar/asymetric cavernous artery velocity measurements, which are greater than 10 cm/sec between sides, or reversal of flow across a collateral may suggest a significant atherosclerotic lesion.

Cavernous artery acceleration time (i.e., PSV divided by systolic rise time) greater than 122 msecmay also indicate Cavernous arterial insufficiency.

Vascular resistive index (RI), based on the formula: RI = PSV – EDV/ PSV .

The parameter is based on the concept that, as penile intracavernous pressure during erection achievement equals or exceeds diastolic pressure, diastolic flow in the corporal bodies will approach zero and the value for RI will approach one.

An RI greater than 0.9 has been associated with normal penile vascular function, and that less than 0.75 is consistent with veno-occlusive dysfunction.

Cavernous artery systolic occlusion pressure (CASOP) -more invasive approach that evaluates the integrity of cavernosal arterial flow by a Doppler transducer during saline intracavernousinfusion.

Cavernous artery intima media thickness as demonstrated by high-resolution echo color Doppler ultrasound has been suggested to be more accurate than PSV in predicting vasculogenicED (Caretta et al, 2009).

The normal inner diameter of cavernosal artery is 0.3- 0.5 mm in normal state and 0.6-.0.8 mm in errect state.

SummaryPSV is the best doppler indicator of arteriogenicimpotence.

EDV is the best doppler indicator of venogenicimpotence.

Penile doppler is the most reliable and least invasive diagnostic modality for assessing ED.

Thank You …