Content written by Irwin Goldstein, MD

The physiologic evaluation of women with sexual health problems, especially arousal and orgasm concerns, involves an assessment of the integrity of multiple biologic systems contributing to sexual function including endocrinologic, neurologic and vascular factors. Concerning blood flow physiology in women, sexual arousal is dependent on the structural and functional integrity of tissue and involves complex neurovascular processes modulated by various local neurotransmitters, vasoactive agents, sex steroid hormones and growth factors consisting primarily of vascular and non-vascular smooth muscle as well as arterioles. This increased pelvic blood flow through the ilio-hypogastric-pudendal arterial bed leads to increased perfusion of the sexual organs, specifically the vagina, clitoris and labia. The resultant increase in blood flow leads to increased engorgement of the clitoral, labial and vaginal erectile tissues, increased diameter of the clitoral corpora cavernosa, the labial corpora spongiosa (vestibular bulb erectile tissue) and increased diameter and length of the vagina.

Animal model data indicate that arterial occlusive pathology in the ilio-hypogastric-pudendal arterial bed is associated with an impaired sexual (pelvic nerve stimulation) arousal response. In the animal model, atherosclerosis of the hypogastric-vaginal-clitoral arterial bed was associated with marked impairment in pelvic nerve mediated changes in genital blood flow. These findings were associated with cavernosal artery atherosclerotic changes, loss of corporal smooth muscle and increase in corporal connective tissue in atherosclerotic compared to control animals. It was concluded that vaginal and clitoral engorgement depended on increased blood inflow, that atherosclerosis was associated with vaginal and clitoral engorgement insufficiency, and that there are at least some cases of female sexual arousal dysfunction associated with arterial vascular insufficiency.

Selective internal iliac arteriography of women with peripheral vascular disease and claudication revealed that there was significant arterial occlusive disease in the pudendal and cavernosal arteries. A pilot unpublished study reviewed pelvic arteriographic studies performed in women who presented with claudication and peripheral vascular disease symptoms. It was concluded that women with peripheral vascular disease had the presence of pelvic atherosclerotic arterial occlusive disease.

Vascular assessment by duplex Doppler ultrasound may be important in the evaluation of women with sexual dysfunction, in particular in women with sexual arousal and orgasm disorders. Women in menopause with arousal and/or orgasm disorders, women with a history of vascular risk factor exposure, and women with persistent genital arousal disorder may be candidates for duplex Doppler ultrasonography.

Diagnostic ultrasonography with a high frequency (12.5) MHz external probe is routinely performed in gray scale and duplex modes.

Gray scale ultrasound technique provides relevant clinical information on the integrity of corpora cavernosa erectile tissue and tunica albuginea. The high frequency MHz small parts probe is placed on one side of the clitoral corpus cavernosum and clitoral diameter is measured from the medial tunica albuginea of the ipsilateral corporal body across the septum to the tunical albuginea of the contralateral corporal body at the level of the mid shaft. Gray scale scanning of the tunica and corporal erectile tissue is then performed.

Duplex Doppler ultrasonography can be used to provide continuous, real time imaging of clitoral arterial and clitoral erectile tissue components recorded at baseline and following sexual stimulation with an erotic video and a vibrator. Duplex Doppler ultrasonography can assess the changes in peak systolic velocity in centimeters per second that occur in the right and left clitoral cavernosal arteries during sexual arousal. Genital tumescence is visually demonstrated on ultrasound, anatomically by increased venous pooling, and physiologically by increased end diastolic velocities in the genital arteries.

Women with arousal or orgasmic dysfunctions who have a history of vascular risk factors and undergo duplex Doppler ultrasonography and, in the presence of adequate sexual arousal, demonstrate impaired increases in post-stimulation clitoral cavernosal arteries, may consider more detailed arterial vascular examination such as endothelial function testing. Also such women may consider low dose vasoactive agent administration with phosphodiesterase type 5 inhibitors as long as their testosterone values are normal.