A physician measures the latency between squeeze and contraction by observing the anal sphincter or by feeling it with a gloved finger in the anus.Nocturnal penile tumescence (NPT)
It is normal for a man to have five to six erections during sleep, especially during rapid eye movement (REM). Their absence may indicate a problem with nerve function or blood supply in the penis. There are two methods for measuring changes in penile rigidity and circumference during nocturnal erection: snap gauge and strain gauge. A significant proportion [give us the percentage] of men who have no sexual dysfunction nonetheless do not have regular nocturnal erections.Penile biothesiometry
This test uses electromagnetic vibration to evaluate sensitivity and nerve function in the glans and shaft of the penis.Dynamic infusion cavernosometry (DICC)
Technique in which fluid is pumped into the penis at a known rate and pressure. It gives a measurement of the vascular pressure in the corpus cavernosum during an erection.Corpus cavernosometry
Cavernosography measurement of the vascular pressure in the corpus cavernosum. Saline is infused under pressure into the corpus cavernosum with a butterfly needle, and the flow rate needed to maintain an erection indicates the degree of venous leakage. The leaking veins responsible may be visualized by infusing a mixture of saline and x-ray contrast medium and performing a cavernosogram. In Digital Subtraction Angiography (DSA), the images are acquired digitally.Magnetic resonance angiography (MRA)
This is similar to magnetic resonance imaging. Magnetic resonance angiography uses magnetic fields and radio waves to provide detailed images of the blood vessels.
Wiley. 7 (1): 501–523. doi:10.1111/j.1743-6109.2009.01626.x. PMID 20092450. External links

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