| Medical diagnosis
There are no formal tests to diagnose erectile dysfunction. Some
blood tests are generally done to exclude underlying disease, such
as diabetes, hypogonadism and prolactinoma. Impotence is also related
to generally poor physical health, poor dietary habits, obesity,
and most specifically cardiovascular disease such as coronary artery
disease and peripheral vascular disease.
A useful and simple way to distinguish between physiological and
psychological impotence is to determine whether the patient ever
has an erection. If never, the problem is likely to be physiological;
if sometimes (however rarely), it is more likely to be psychological.
The current diagnostic and statistical manual of mental diseases
(DSM-IV) has included a listing for impotence.
Clinical tests used to diagnose ED
Duplex ultrasound
Duplex ultrasound is used to evaluate blood flow, venous leak, signs
of atherosclerosis, and scarring or calcification of erectile tissue.
Injecting prostaglandin, a hormone-like stimulator produced in the
body, induces erection. Ultrasound is then used to see vascular
dilation and measure penile blood pressure. Measurements are compared
to those taken when the penis is flaccid.
Penile nerves function
Tests such as the bulbocavernosus reflex test are used to determine
if there is sufficient nerve sensation in the penis. The physician
squeezes the glans (head) of the penis, which immediately causes
the anus to contract if nerve function is normal. A physician measures
the latency between squeeze and contraction by observing the anal
sphincter or by feeling it with a gloved finger inserted past the
anus. Specific nerve tests are used in patients with suspected nerve
damage as a result of diabetes or nerve disease.
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.
Penile biothesiometry
This test uses electromagnetic vibration to evaluate sensitivity
and nerve function in the glans and shaft of the penis. A decreased
perception of vibration may indicate nerve damage in the pelvic
area, which can lead to impotence.
Penile Angiogram
Invasive test - allows visualization of the circulation in the penis
and is used during the repair of a priapism.
Dynamic Infusion Cavernosometry
(Abbreviated 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. To do this
test, a vasodilator like prostaglandin E-1 is injected to measure
the rate of infusion required to get a rigid erection and to help
find how severe the venous leak is.
Corpus Cavernosometry
Cavernosography is an adjunct to Dynamic Infusion Cavernosometry,
where a contrast material is injected and then it is x-rayed to
visualize any leakage.
Digital Subtration Angiography
In DSA, the images are acquired digitally. The computer crates a
mask from lower-contrast x-rays of the same area and digitally isolates
the blood vessels (this is done manually through darkroom masking
with traditional angiography).
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. Doctors may inject a "contrast
agent" into the patient's bloodstream that causes vascular
tissues to stand out against other tissues. The contrast agent provides
for enhanced information regarding blood supply and vascular anomalies.
Aside from the IV used to introduce the contrast material into the
bloodstream, magnetic resonance angiography is noninvasive and painless.
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