Penile Duplex Doppler Ultrasonography

Diagnosis

Peak systolic velocity (cm/s)

End diastolic velocity (cm/s)

Normal (Fig. 6.10)

>35

Cavernosal artery insufficiency (Fig. 6.11)

<30

Venous leak (Fig. 6.12)

>35

Mixed vasculogenic disease (Fig. 6.13)

<30

Indications

1.

Erectile dysfunction
2.

Evaluate for AV fistula
3.

As part of penile deformity assessment (Peyronie’s disease)

Pre-procedural Considerations

1.

Assess the patient’s blood pressure and heart rate prior to administering any vasoactive agent. While hypertension is not a contraindication to receiving vasoactive medication intracavernosally, should the patient experience a prolonged erection, intracavernosal phenylephrine (or other alpha-adrenergic agonists) should not be given to a patient with baseline hypertension, for fear of inducing a malignant hypertensive episode.
2.

Check that the patient is not taking MAOIs as this is a true contraindication to using intracavernosal phenylephrine (or other alpha-adrenergic agonists).
3.

Encourage the patient to avoid use of PDE5i the morning of the procedure. However, a patient who is using stable daily dose of tadalafil for ED or BPH/LUTS may continue his medication regimen.
4.

Some patients might benefit from the use of audiovisual sexual stimulation (AVSS) by means of adult reading material or videos to help them increase arousal and relax.
5.

For intracavernosal injection, we use trimix (papaverine 30 mg, phentolamine 1 mg, alprostadil 10 μg) if the patient is injection naïve. Other injection agents may be used such as papaverine monotherapy, bimix (papaverine + phentolamine), and PGE monotherapy (Caverject^®, Pfizer Inc., New York, NY; Edex^®, Auxilium Pharmaceuticals, Inc., Chesterbrook, PA) as long as the goal of achieving complete cavernosal smooth muscle relaxation is appreciated.
6.

It is necessary to have an ultrasound machine with color duplex Doppler capabilities and a high frequency , preferably a 7.5–15 MHz linear transducer. Doppler angle should be set at 60° of insonation (Fig. 6.1).

Fig. 6.1

Picture of ultrasound machine and probe
7.

Positioning: for penile imaging the patient should be supine; however, for perineal imaging, the patient should be frog legged . The penis should be oriented upward with the glans grasped by the patient himself to stabilize the penis for examination.
8.

A dosing sheet and report sheet are useful in keeping track during and after the procedure (Figs. 6.2 and 6.3).

Fig. 6.2

Sample dosing sheet

Fig. 6.3

Sample report sheet

List of Necessary Equipment

1.

29-gauge insulin syringe
2.

Injectable vasoactive medication
3.

Alcohol prep pads
4.

Non-sterile gloves
5.

Report sheet
6.

Ultrasound machine, probe, and ultrasound gel

Procedure

A redosing schedule should be utilized in an effort to overcome intracavernosal adrenaline and achieve complete smooth muscle relaxation. Approximately one half of men seen by us with a diagnosis of venous leak based on an outside DUS have a normal DUS result when repeated at our center . This is the result of underdosing and failure to achieve maximal smooth muscle relaxation and thus a false diagnosis of venous leak is given. The agent and the dose of medication are less important than the outcome. At our center as previously mentioned, we use trimix . We commence with a first dose of trimix five units (unless the patient happens to already be using intracavernosal injections and then we will use his at home agent/dose), and if optimal rigidity has not been achieved in 10 min, a second and possibly a third dose of trimix ten units will be given. The decision to redose is based on two main factors, penile rigidity and EDV values. Failure to achieve a BQE (unless the study is normal) and elevated EDVs dictates administering a second or third dose of vasoactive agent.

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