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St Peter's
Andrology Centre

What is
Sexual Medicine?

What is a
Sexual Problem?


Your Consultation

Special Investigations

Medico-legal Services

Dr John Dean

Literate Systems

Special Investigations

Most people with sexual problems are advised to have a blood test, looking for evidence of hormone and general health problems. More intensive, specialised investigations are only needed by a small minority, but we have rapid access within The London Clinic to all the investigations that are likely to be required.

Nocturnal penile tumescence (NPT) and rigidity monitoring: NPT testing is primarily used to confirm whether or not an erection problem has predominantly a physical or psychological cause. The test involves the detection of erections and measurement of erection rigidity during the hours of sleep, when anxiety and other distractions are not present. The device, called a RigiScan®, consists of an electronic recorder and two fine, elastic band-like strain gauges, which are worn around the base and near the tip of the penis. These continuously monitor and record penile activity during the assessment. This is an entirely painless investigation but does require one or two overnight hospital admissions to get reliable results; we do not usually offer home testing.

Duplex Doppler penile ultrasound (DDPU): DDPU is a minimally-invasive method for evaluating blood flow in penile arteries and veins in men with erectile dysfunction. It can provide objective evidence of arterial inflow problems in men with vascular disease and also identify abnormal arterio-venous vascular communications that may contribute to erection problems that follow penile or pelvic injury, or in men with lifelong problems. The test involves giving an injection of an erection-promoting drug into the penis, after which an ultrasound scan is performed. It is usually required in men who are resistant to oral therapies for ED, and for those who develop ED after trauma.

Dynamic infusion cavernosometry and cavernosography (DICC): Dynamic infusion cavernosometry is a technique in which fluid is pumped into the penis at a known rate and pressure. It allows the physician to measure the pressure within the erectile tissue (corpora cavernosum) during erection. The test involves giving an injection of an erection-promoting drug into the penis, after which the rate of infusion required to get a rigid erection is measured. Cavernosography involves the injection of a material that is opaque to X-rays, after which x-ray screening allows the accurate visualisation of the site of any leakage. DICC is used to assess the severity of venous leakage from the penis during erection when this is suspected as the principal cause of an erection problem. Only a small number of men will require this investigation as a part of their assessment; they will have previously had an abnormal DDPU that suggested venous leakage as a significant contributory factor to their ED.

Selective internal pudendal arteriography: Selective pudendal arteriography is a technique used to identify the precise location of vascular lesions that may be causing erectile dysfunction. It is performed by a radiologist; it involves the careful manoeuvring of a vascular catheter from an artery in the groin into the arteries that supply the genitalia. Once this has been achieved, a material that is opaque to X-rays is injected, which allows visualisation of the arterial anatomy and any blockages or abnormal communications by x-ray screening. Sometimes a well-localised lesion can be dealt with during the procedure, by dilating a narrowing in a blood vessel or blocking off an abnormal communication. However, most lesions will need a separate microvascular surgery procedure to resolve them.

This procedure is only rarely required as a part of the assessment of ED; such men will previously have had an abnormal DDPU that suggested an arterial inflow problem as a significant contributory factor to their ED. It may be necessary in some men with lifelong problems that may be due to a structural abnormality in the penile blood supply, or in men who have had a pelvic fracture, penile trauma, prolonged erection or embolism (blood clot lodged in an artery). It does not normally provide useful information in men with widespread vascular disease due to diabetes and atherosclerosis (generalised “hardening of the arteries”).


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