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How
is ultrasound ( sonography) used for treating
infertility ?
Ultrasound or sonography has helped
revolutionize our approach to the infertile patient.
Ultrasound machines are a very useful addition to the
gynecologist?s bag of tricks; and help him to "image"
or see structures in the female pelvis. Ultrasound uses
high frequency sound waves much like SONAR machines
used in ships for detecting submarines underwater. The
high frequency sound waves are bounced off the pelvic
organs; and the reflected sound waves are received by
the probe ( transducer) and a computer is used to reconstruct
the waves into black and white images on the monitor.
Ultrasound machines today are all real-time machines,
which give dynamic images.
In the old days, ultrasound for infertility
was done through the abdomen. This required you to fill
up your bladder ( till it was ready to burst !) so that
the sound waves could be transmitted into the pelvis.
However, the standard ultrasound technique today for
infertility is vaginal ultrasound ( endovaginal scanning)
in which a long, slim, slender probe is inserted into
the vagina and used for imaging the pelvic organs. Not
only is this much more comfortable for you; it also
gives much sharper and clearer pictures, since the probe
is much closer to the pelvic structures.
What can you see on ultrasound? The
ultrasound gives clear pictures of the uterus; and the
ovaries. It allows the doctor to look for fibroids;
ovarian cysts; and ectopic pregnancies. It is also excellent
for early diagnosis of pregnancies. However, the ultrasound
scan is not very good for assessing whether or not the
tubes are normal.
How
is ultrasound used for follicular scanning to monitor
ovulation ?
Ovulation scans allow the doctor to
determine accurately when the egg matures; and when
you ovulate. This is often the basic procedure for most
infertility treatment since the treatment revolves around
the wife's ovulation. Daily scans are done to visualize
the growing follicle, which looks like a black bubble
on the screen. Most women can see the follicle clearly
for themselves - and know by the scans when the egg
has ruptured. Other useful information which can be
determined by these scans is the thickness of the uterine
lining - the endometrium. The ripening follicle produces
increasing quantities of estrogen, which cause the endometrium
to thicken. The doctor can get a good idea of how much
estrogen you are producing (and thus the quality of
the egg) based on the thickness and brightness of the
endometrium on the ultrasound scan.
Fig 1. Ultrasound scan showing multiple follicles
Fig 2. Ultrasound scan of the uterus, showing a normal
endometrium, which appears as a triple band in the center
of the uterus
What if
an ovarian cyst is found on ultrasound scans ?
One of the commonest findings on an
ultrasound scan is an ovarian cyst. A cyst is a collection
of fluid surrounded by a thin wall (a fluid-filled sac)
that develops in the ovary. Typically, ovarian cysts
are functional (not disease-related) and disappear on
their own. During ovulation, a follicle may grow , but
fail to rupture and release an egg. Instead of being
reabsorbed, the fluid within the follicle persists and
forms a follicular cyst.
The other type of functional cyst is
a corpus luteum cyst, which develops when the corpus
luteum fills with blood. Functional ovarian cysts usually
resolve on their own, and are not to be confused with
other pathological conditions involving cystic ovaries,
specifically polycystic ovarian disease, endometriotic
cysts, or ovarian tumours.
Since an ultrasound picture is just
a black and white shadow, the doctor has to be skillful
in interpreting what the image means. Simple cysts are
thin walled, and appear as a large black bubble. Cysts
which contain blood ( for example, chocolate cysts found
in patients with endometriosis) will have echoes within
them, which appear white, and these are described as
complex masses on ultrasound. The incidence of follicular
cysts is increased in infertile patients taking drugs
(such as clomiphene and HMG) for ovulation induction.
Functional ovarian cysts usually disappear within 60
days without treatment. However, if the cyst is larger
than 6 cm, or persists for longer than 6 weeks, then
further testing may be needed.
Who should do the ultrasound
scans ?
Who does the scans? Ultrasound scans
can be done either by a radiologist; or by the gynecologist
or infertility specialist himself. Remember that the
eye only sees what the mind knows, so you must go to
a good clinic for your scans.
The benefit of having the scans done
by the infertility specialist himself is that he can
make immediate decisions regarding your treatment based
on the scan findings. If the radiologist does the scans,
then you have to wait till your doctor has seen the
report before knowing what to do next since the radiologist
does not make the treatment decisions.
In any case, it is vital that the ultrasound
scans be done in the Infertility Clinic itself, so that
your waiting can be minimized - and you don't have to
run around from the sonographer to the gynecologist.
If there are any abnormal findings, it is vital that
your gynecologist see the actual ultrasound for himself
during the scan. This provides much more information
than the printed pictures.
Today, thanks to the magic of telemedicine,
many of our patients can email the jpeg images of their
ultrasound scans to us, wherever in the world they may
be, so we can actually "see " the images and interpret
them ourselves.
What recent
advances have occurred in ultrasound ?
Ultrasound technology has made dramatic advances in
recent years, and now tests have been described which
allow the doctor to use ultrasound to assess tubal patency.
Basically, these involve passing a fluid into your tubes
through the uterus; and the gynecologist can see the
passage of the bubbles into the tubes and out into the
abdomen. Since this test ( sonosalpingography) can be
done in the doctor's clinic itself, and does not involve
X-ray radiation, it has advantages - especially for
documenting that the tubes are normal. However, the
gold standard for tubal testing remains HSG
( hysterosalpingography, an X-ray of the uterus and
tubes) and laparoscopy today, because it provides us
with a "hard copy" image which can be critically examined.
Doppler: The newer ultrasound machines
have Doppler attachments which allow the doctor to judge
the flow of blood in the blood vessels. Colour Doppler
allows the doctor to "see " the blood flow in the pelvic
blood vessels, mapped in color on the monitor. While
still a research tool, it may provide important information
for assessing the infertile patient in the coming years.
Three ? dimensional ultrasound. Using
sophisticated microprocessors, the newest ultrasound
machines allow the doctor to reconstruct the image,
so that he gets a three dimensional view. While this
provides excellent pictures, the true value of this
technique for infertility still has to be evaluated.
It can be useful in assessing women with uterine anomalies,
because it helps the doctor to differentiate between
a septate uterus and a bicornuate uterus.
How
can ultrasound guided procedures be used to treat
infertility ?
Ultrasound now also offers infertile
patients newer treatment options not available before.
Modern surgical techniques have progressively become
less and less invasive - all to the patient's benefit
! From laparotomy to laparoscopy , and now to ultrasound
guided procedures, we are witnessing a change in the
gynecologist's armamentarium from the knife to the endoscope
to the guided needle !
The benefits to the patient of "minimally
invasive surgery" are many and include : reduced costs;
reduced hospitalisation ; reduced risk of complications;
and better preservation of fertility, with increased
chance of conception for the future.
Ultrasound-guided procedures can be
used to treat a variety of problems seen in the infertile
woman:
- Egg pickup for IVF - The use
of vaginal ultrasound for egg pickup has made egg
retrieval a short, simple and inexpensive procedure,
which can be performed in a day-care unit, under sedation
and local anesthesia . The ovaries are normally present
in the pouch of Douglas, and are very accessible transvaginally.
Moreover, the presence of adhesions does not interfere
with egg collection.
- Ovarian cyst aspiration. An
ovarian cyst is a very common condition in which fluid
collects in the ovary. However, cysts which are more
than 5 cm in size need to be treated, as they can
cause problems ( eg twisting and rupture). Normally,
surgery had to be done to remove these cysts - and
often this damaged the surrounding normal ovary as
well. With ultrasound-guidance, we can stick a needle
from the vagina into the cyst, and empty the contents
( usually clear fluid ) by sucking it out. This empties
the cyst, which often does not recur.
- Treatment of ectopic pregnancy
. With technological advances ( ultrasound and beta-HCG
blood tests) the diagnosis of tubal pregnancy can
be made very early, usually before rupture. It can
be treated by injecting a toxic chemical, methotrexate,
into the sac, which causes the tissue to die and then
get reabsorbed, without any surgery whatsoever. In
more advanced tubal pregnancies, potassium chloride
can be injected direct into the heart of the baby
in the ectopic gestational sac, thus killing it and
preventing it from growing.
- Ultrasound-guided tubal embryo
and gamete transfer for IVF and GIFT techniques. Techniques
have been devised to pass a special tube - the Jansen-Anderson
catheter set - into the fallopian tubes through the
vagina under ultrasound guidance, so as to place the
embryos and /or the gametes in the fallopian tube.
Since the tube offers a better environment for the
gametes and embryos than the uterine cavity, it is
believed that this will improve pregnancy rates.
- Tubal recanalisation for cornual
blocks (proximal tubal obstruction). Often cornual
blocks are due to the presence of mucus plugs and
amorphous debris in the tubal lumen. Ultrasound guided
tubal catheterization can effectively treat the blocked
tubes in some of these patients.
The scope of ultrasound guided
procedures has increased dramatically in the last few
years; and with further improvements in technology,
we can expect this list to become even longer, and doctors
become more versatile with using this technology.
Ultrasound monitoring during an IVF cycle
Ultrasound guided egg retrieval for IVF
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