What
is Ductography/Galactography and Why is it Performed?
Ductography
(also called galactography or ductogalactography) is a special
type of contrast enhanced mammography used for imaging the
breast ducts. Ductography can aid in diagnosing the cause
of an abnormal nipple discharge and is valuable in diagnosing
intraductal papillomas and other conditions. Papillomas are
wart-like, non-cancerous tumors with branchings or stalks
that have grown inside the breast duct; they are the most
common cause of nipple discharge.
Nipple
discharge can be caused by non-cancerous tumors (such as papillomas)
or cancer (such as ductal carcinoma in situ, DCIS). However,
the majority of nipple discharges are due to benign (non-cancerous)
causes. In particular, discharges that are yellow, green,
blue, or black in color are usually categorized as less suspicious.
For example, blue or black discharges are often associated
with benign cysts. Discharges that are bloody, colorless,
or clear in color are categorized as more suspicious, but
further investigation usually results in a benign diagnosis.
Bilateral nipple discharge (discharge occurring from both
breasts) is usually benign and does not typically require
investigation with ductography or other procedures. However,
all persistent discharges should be reported to a physician
for evaluation.
Most women
are able to undergo ductography. However, it may be more difficult
to perform ductography in:
Screening
mammography and diagnostic mammography differ from ductography
in that they do not use contrast injection. Ductography is
a specialized procedure and is only performed at select centers
and hospitals by radiologists with significant experience
with ductography. Many healthcare locations that perform screening
or diagnostic mammography do not perform ductography.
How
is Ductography Performed?
The ductography
procedure takes between 30 minutes to an hour. Patients referred
for ductography most always have nipple discharge at the time
of the study. Before performing the procedure, the nipple
is usually cleaned and sterilized with an alcohol swab or
other material to remove any dried discharge. The radiologist
then applies manual pressure to the breast to elicit a fluid
discharge. In patients who experience nipple discharge, there
is often a "trigger" spot that causes discharge
from the nipple when pressure is applied to it. After identifying
the discharging duct, the radiologist feeds a small hollow
needle (called a blunt-tipped cannula) into this area of the
nipple while stabilizing the nipple between his or her thumb
and forefinger. Usually, no force, only downward guidance,
is needed to insert the cannula into the patients breast
duct.
Once the
cannula has been gently fed down the duct, a small amount
of radiopaque substance (contrast media) is injected into
the breast through a syringe that is connected to the cannula.
The cannula is removed and a small amount of collodio (sealant)
is applied to the nipple. The breast is then imaged with mammography;
the radiopaque contrast helps enhance the duct anatomy on
the resulting images. After the procedure is completed, a
bandage is typically placed over the nipple to prevent fluid
or dye from staining the patients clothes.
The radiopaque
contrast media is a pharmaceutical liquid made up of substances
that weaken (attenuate) x-rays as they pass through the organ
containing the contrast (in this case, the breast duct). The
breast duct filled with contrast is then seen more clearly
on the resulting mammogram image and allows the radiologist
to better visualize intraductal papillomas or other abnormalities
that may be present. The abnormality in the breast appears
as a black nodule in the middle of the white duct.
If the
radiologist has difficulty feeding the cannula into the breast
duct, a local anesthetic gel or warm compress or washcloth
is often used before re-attempting the procedure. Some physicians
coat the tip of the cannula with anesthetic gel and also dab
it on the surface of the nipple. If the cannula is still unable
to be thread into the breast duct after three attempts, the
procedure is typically canceled and rescheduled for one to
two weeks later.
Is
Ductography Painful?
A ductogram
procedure can be mildly uncomfortable but is not usually painful.
A ductogram is likely to be more uncomfortable when there
is not a significant quantity of nipple discharge, making
it difficult for the physician to find the opening of the
discharging duct. This may require "probing" to
find the right duct. If there is significant fluid discharge,
the needle (cannula) insertion into the breast duct is usually
much easier to perform and less uncomfortable for the patient.
The syringe
is used to slowly instill the contrast material through the
needle (cannula) into the breast duct. This is not painful
but may cause a "full" sensation similar to when
the breast fills with milk during lactation (breast-feeding).
If the patient feels fullness or pain during the injection
of contrast, she should tell the radiologist. The goal is
to completely fill the duct with contrast to get the best
image possible. A sensation of pressure or "fullness"
is a good sign that the duct is full and distended (enlarged).
However, care should be taken to avoid overfilling because
this can hide abnormalities.
In some
cases, extravasation may occur during ductography. Extravasation
is the flow of contrast media from the breast duct out into
the surrounding breast tissue. If extravasation occurs, the
cannula is removed from the breast and the patients may be
treated with a pain reliever (such as ibuprofen) if necessary.
The procedure is usually rescheduled for a later date, typically
one to two weeks later. To help minimize the occurrence of
extravasation, ductography should be performed by radiologists
with significant experience with the procedure.
What
Treatment May Follow Ductography?
The ductogram
(also called galactogram) may or may not identify the cause
of the nipple discharge. The majority of patients who undergo
ductography ultimately need surgery to treat the discharge.
Surgery may involve removing a papilloma or other nodule in
the breast duct. In some cases, removal of the entire ductal
system may be required. For example, some patients with duct
ectasia (widening and hardening of the duct) may need surgery
to remove the affected duct if other treatments, such as heat
compresses, do not help.
Even if
the cause of discharge is still unknown after ductography,
the ductogram can still help the surgeon find the affected
duct so that only that duct needs to be removed. This is accomplished
by mixing blue dye with the radiographic contrast so the surgeon
can see the abnormal duct as blue.
Some surgeons
feel that ductography is unnecessary since the patient will
likely need surgery anyway. However, identifying the type
of abnormality, the number of abnormalities, and their extent
in the breast can be very helpful in aiding the surgeon in
either removing as little tissue as necessary or in making
sure to remove all of the involved tissue associated with
extensive abnormalities.