Penile US and Doppler US

Penile US and Doppler US

Min Hoan Moon, M.D., Il Sung Hwang, M.D., Jung Suk Sim , M.D., Seung-Hyup Kim, M.D.

Department of Radiology Seoul National University College of Medicine, Seoul, Korea

Introduction

US and Doppler US are being used as primary imaging modalities in the evaluation of the patient with erectile dysfunction and various other penile disease. This exhibit will illustrate (1) the technique and normal findings of penile US and Doppler US (2) color / power / spectral Doppler US in the normal variation, arteriogenic and venogenic impotences, diabetic arteriopathy, arteriovenous fistula and Peyronie's disease. This exhibit will also include the Doppler findings of priapism. The findings in other imaging modalities such as penile arteriography and corpus cavernosography will be compared.

Penile anatomy

cavernosal artery is measured. Two or three minutes after an intracavernosal injection of 10 -15 ?g of prostaglandin -E1, the inner diameter of the cavernosal artery is measured again and Doppler spectra are obta ined from the proximal cavernosal arteries at the base of the penis. The d orsal penile arteries and deep dorsal vein are also evaluated. Doppler angle is kept

between 30 -60 degrees. The sample volume and wall filter are fixed at minimum. Color or power Doppler US improves the localization of the penile vessels and thus permits more rapid acquisition of Doppler waveforms.

Normal Penile US & Doppler US

Normally the corpora cavernosa are symmetric and

have homogeneous medium-level echoes. The

*

tunica albuginea appears as a thin echogenic line

surrounding the corpora. The cavernosal arteries

(asterisk) are located slightly medially in the

corpora.

A

B

Diagram of the penile anatomy

( Reprinted from reference 4 )

A. Cross-sectional diagram of the

penile shaft near the base

illustrates compartments of the

penis.

B. Diagram of typical penile arterial

anatomy.

C. Diagram of typical penile venous

C

anatomy

The penis is made up of three corporal bodies: Two corpora cavernosa and a single corpus spongiosum. Corpora cavernosa are main erectile bodies and corpus spongiosum contains the urethra. A septum divides two corpora cavernosa but contains fenestrations that provide communications between both corpora.The blood supply of the penis is primarily from the internal pudendal arteries that originate from the anterior division of t he internal iliac arteries. Each internal pudendal artery gives off the penile artery proper which branches into a cavernosal artery and a dorsal artery at the base of the penis. The cavernosal arteries are the primary source of blood flow to the corpora cavernosa while dorsal arteries supply blood to the skin and glans of the penis. Venous drainage from the corpora cavernosa is through small emissary veins, which drain into the dorsal, crural, and cavernosal veins.

Penile Doppler: Technique

A

B

C

The normal progression of cavernosal arterial flow during penile erection(A) is

well known. In the flaccid state, monophasic flow is present with minimal diastolic flow. With the onset of erection, there is an increase in both systolic and diastolic

flow(B). As intracavernosal pressure increases, a dicrotic notch appears and a decrease in diastolic flow occurs. With continuously increasing pressures, enddiastolic flow declines to zero and then undergoes diastolic flo w reversal(C). Then

the systolic envelop is narrowed and diastolic flow disappears completely with firm erection.

Erectile Dysfunction

Erectile dysfunction can result from psychogenic, neurogenic, arteriogenic, and venogenic causes. Often more than one causes are combined. Establishing a specific cause is important particularly in young men because of the frequency of correctable vascular abnormalities. Organic causes of erectile dysfunction are found in 50-90%, and organic impotence in the presence of normal endocrine balance and intact nervous system is vascular in origin in about 50-70%, either arterial insufficiency or venous incompetence. Pure arteriogenic impotence accounts for about 30% of cases and isolated venogenic impotence is found in about 15%.

Arteriogenic Impotence

A

dorsal artery

cavernosal artery

deep dorsal vein superficial dorsal vein

Illustration showing penile Doppler technique ( reprinted from reference 5)

Doppler US is performed with the patient supine and the penis in the

anatomic position, lying on the anterior abdominal wall. High-resolution US

scanners with frequencies of 5-10MHz are used. The followings are our

D

protocol of penile Doppler US. In the flaccid state, the inner diameter of the

B

C

A 32 year-old man with posttraumatic arteriogenic impotence A.Iliac angiogram shows near total occlusion of left

internal iliac artery. B.On selective internal pudendal angiogram (right ),

left cavernosal artery is also seen (arrow). C.Transverse color Doppler flow image shows collateral

supply(arrow) from right cavernosal artery. D.On spectral waveform obtained after prostagladin-E1

injection, the peak systolic velocity is less than 25 Cm/sec, indicating arterial insufficiency.

The parameters that indicate the presence of arterial disease are a subnormal clinical response to vasoactive agents, a less than 60% increase in the diameter of the cavernosal artery, and a peak systolic velocity of the cavernosal arteries less than 30cm/sec.

Venogenic Impotence

A 47 year-old man with

venogenic impotence.

Spectral waveform(A)

obtained after PG-E1

injection shows persistent

diastolic flow of cavernosal

artery. Cavernosogram(B)

confirms veno-occlusive

A

B

failure

Another patient with

venogenic impotence.

Spectral waveform(C)

obtained from cavernosal

artery after PG-E1 injection

shows continuous diastolic

flow. Doppler of dorsal vein

(D) demonstrates steady

C

flow in the dorsal vein.

In the presence of normal arterial function, Doppler findings suggestive of an abnormal venous leak are persistent end -diastolic velocity of the cavernosal artery greater than 5cm/sec and demonstration of flow in the deep dorsal vein. The development of diastolic flow reversal after an injection has been found to be a reliable indicator of venous co mpetence.

Diabetic Arteriopathy

A 52 year-old man with diabetes mellitus. Color Doppler image (A) shows calcification of cavernosal arterial wall. On spectral waveform (B), obtained from cavernosal artery after PG-E1 injection, the peak systolic velocity is less than 30 Cm/sec.

Diabetes mellitus in particular is thought to be responsible for a significant

number of cases of erectile failure. The detrimental effects of diabetes on male sexual function appear to be manifestations of generalized damage to both blood vessels and peripheral nerves. Peripheral sensory and autonom-

ic neuropathy has been well documented in the diabetic patient pop ulation. Evidence also suggests that this disease leads to development of profound arterial small vessel disease involving penile arteries and their tributaries. Although controversy exists concerning the primary pathophysiologic mech-

anism by which diabetes influences erectile function, studies showing the presence of arteriogenic impotence in the absence of significant neuropathy indicate that arterial occlusive disease may be more detrimental to male

sexual function in the diabetic patient population.

Priapism

A

B

A 27 year-old man with drug induced priapism.

Color Doppler image shows no demonstrable blood flow within cavernosal artery (A). After needle aspiration, blood flow through cavernosal artery is restored (B).

*

C

D

A 34 year-old man with posttraumatic "high flow" priapism. Sagittal color Doppler image (C)

shows abnormal ,asymmetric blush of color flow (asterisk), adja -

cent to the artery. In the flaccid state, there is an increase in both

systolic and diastolic flow (D).

Priapism is a prolonged penile erection not associated with sexual stimulation. Two forms of priapism are known to occur. The more common type, the veno-occlusive form, is manifested by a painful erection and is chara cterized by ischemia, venous stasis, and pooling of blood within the corpora cavernosa. The pathophysiologic mechanism of venous priapism is blood clot in the corpora impeding venous drainage. It is usually idiopathic, though it is more common in patients with sickle cell traits. An uncommon type, arterial (high flow) form is associated with painless erection and usually is of traumatic origin. The pathophysiologic mechanism of high flow priapism is thought to be unregulated arterial inflow.

Peyronie's Disease

*

*

*

*

A

B

C

Peyronie's disease.Plain radiograph (A) demonstrates linear radioopacity (arrow). Transverse sonogram (B) & longitudinal sonogram (C) shows echogenic line with posterior shadowing (asterisks), regarded as calcified plaque.

Peyronie's disease is fibrosis of the tunica albuginea covering the corpora cavernosa. The cause is unknown, but it is thought to represent an inflammatory response or a vasculitis. The disease usually involves the dorsum of the penis, but it can involve any portion of the tunica albuginea including intercavernosal septum. During erection the penis bend s toward the side of the fibrosis, since the involved portion of the corp ora can not lengthen normally. The condition can be painful, and it can be a cause of impotences. The sonographic findings include a thick echogenic plaque with echogenecity similar to or higher than the tunica albuginea; a calcified plaque in thickened tunica albuginea; and are occasionally associated with calcification in the corpora cavernosa.

Penile Fracture

A

B

A 34 year-old man with penile trauma. Transverse sonogram(A) shows fluid collection(arrows) on the ventral aspect of the penile shaft. This fluid collection has

partial septation(arrow in B). In this patient, interruption of the tunica albuginea is not demonstrated.

A penile fracture is a tear in the tunica albuginea. Penile fractures results from acute bending of the erect penis. Fractures can be diagnosed sonographically by visualizing interruption of the thin echogenic line of the tunica albuginea. Heterogeneous echoes caused by blood and disrupted corporal tissue usually are seen in the lesion of tear.

Reference

1.Schwartz AN, Wang KY, Mack LA, Lowe M, Berger RE, Cyr DR, Feldman M.

Evaluation of normal erectile function with color flow Dopple r sonography.

AJR 1989;153:1155-1160

2.Benson CB, Vickers MA, Aruny J. Evaluation of impotence. Semin Ultrasound

CT MR 1991;12:176-190

3.Fitzgerald SW, Erickson SJ, Foley WD, Lipchik EO, Lawson TL. Color Doppler

sonography in the evaluation of erectile dysfunction. RadioGraphics

1992;12:3 -17

4.Fitzerald SW, Foley WD. Color Doppler imaging of the genitourinary system.

In: Foley WD, ed. Color Doppler flow imaging.Readinh, Mass: Andover, 1991;

153-170

5.

. Imaging of the penis.

117-128, 1999

6.Kim SH, Paick JS, Lee SE, Choi BI, Yeon KM, Han MC. Doppler sonography

of deep cavernosal artery of the penis: variation of peak systolic velocity

according to sampling location. J Ultrasound Med 1994;13:591-594

7.Amin Z, Patel U, Friedman EP, Vale JA, Kirby R, Lees WR. Color Doppel r

and duplex ultrasound assessment of Peyronie's disease im impotent men. Br

J Radiology 1993;66:398-402

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