How is ultrasound (sonography) used for treating infertility ?
How is ultrasound used for follicular scanning to monitor ovulation ?
What if an ovarian cyst is found on ultrasound scans ?
Who should do the ultrasound scans ?
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.
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
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 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.
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