Pelvic Ultrasound

Overview of Pelvic Ultrasound

Ultrasound, often referred to as US, is a major tool used to check what’s happening inside the female pelvis. It provides clear pictures of the uterus, ovaries, and other parts within the body. The advantages of using ultrasound are that it’s easy to carry around, fairly cheap, and safer compared to other methods because it doesn’t involve any harmful radiation. This is especially important when inspecting the ovaries in younger girls and women in their childbearing years, as these organs can be damaged by radiation.

There are two ways doctors can conduct a pelvic ultrasound, either transabdominally (TA), meaning through the abdomen, or transvaginally (TV), which is done through the vagina. During the ultrasound, a kind of gel is put on the skin over the bladder. This eliminates air between the device, called a transducer, and the skin, allowing for better images. A bladder filled with urine helps move the small intestine upwards, out of the pelvis. This creates a clearer pathway for the ultrasound waves, preventing them from being distorted by air in the intestine.

The ultrasound machine takes images in multiple directions and angles to ensure a complete overview. It does this in real-time, which lets the expert handling the device adjust it to get the clearest images, even if the organs aren’t perfectly aligned. Typically, the uterus is located in the middle, with the ovaries and adnexa (surrounding parts) on each side. However, both the uterus and ovaries can be positioned differently in various women, so they might appear in the lower, middle, or upper pelvic area, or even above the uterus.

Anatomy and Physiology of Pelvic Ultrasound

The uterus and cervix are examined using different forms of imaging, such as regular and lateral views. This allows doctors to look at the uterus from top (fundus) to bottom (cervix) and give a thorough check on its size and shape. This can help them spot any abnormalities, like non-cancerous growths called leiomyomas. The uterus’ endometrial cavity, where a baby can grow, might also show different patterns or colors on imaging if something is blocking it, as it happens in older women who had radiation treatment or in kids with a medical condition called hematometrocolpos, which causes the collection of blood in the vagina. Otherwise, the lining of the uterus (endometrium) is usually seen with a different appearance than the rest of the uterus and can vary depending on the patient’s hormone levels, age, and menstrual cycle.

Usually, in the first half of the menstrual cycle, the endometrial lining is highly reflective on imaging and has a three-layered structure. In the second half of the cycle, the lining is uniformly reflective. For women who’ve gone through menopause, the lining should not be thicker than 5mm, except for those taking a medication called tamoxifen. Sometimes, the endometrial lining can be notably pronounced due to the presence of uterine myomas, polyps, or other growths, especially in postmenopausal women who’ve unexpected bleeding. To assess what’s inside the endometrium, doctors can use a technique called hysterosonography, where they inject a fluid through the cervix and take a transvaginal ultrasound image.

Ovaries and the other structures surrounding the uterus like the fallopian tubes, are evaluated through the same imaging techniques. Ovaries typically look like almond shapes situated usually on the sides of the uterus. The appearance of ovaries, including the presence and number of egg-producing cells or small fluid-filled sacs (follicles/cysts) varies depending on age, hormonal functionality, and menstruation cycle. For instance, in a condition called ovarian torsion, where the ovary twists, causing severe pain and other problems, the ovary can grow 3 to 4 times its normal size. The comparison between the two ovaries is important in such a scenario. In conditions like pelvic inflammatory disease, both ovaries will enlarge but not as much as in ovarian torsion.

Also, other structures in the pelvic region area like hernias, fallopian tubes, free fluids, etc. can be inspected through pelvic ultrasound. For example, fallopian tubes might appear as expanded fluid-filled tubes due to blockage, usually resulting from a chronic infection. Occasionally, a fallopian tube could even twist. Fluid that has heterogeneous appearance or is sectioned suggests a complex component such as bleeding, infection, or protein-rich fluids. Various other diseases like appendicitis, inflammation of the small pouches in the large intestine (diverticulitis), and cancers like appendiceal mucocele can also be sometimes seen through imaging.

When it comes to males, ultrasound use is quite limited for the pelvic region. However, conditions like undescended testes in the groin and hernias can be seen using high-frequency linear array transducers. Previously for examining the prostate and seminal vesicles, transrectal imaging was used, but now Magnetic Resonance Imaging (MRI) is becoming more common. Ultrasound can also provide a view of the enlarged urethra in a condition known as posterior urethral valves, and sometimes even the valve itself can be seen. Views angled downwards and centrally are most helpful in these scenarios. Transperineal ultrasound, which is applied through the skin between the anus and scrotum, can also be utilized for the diagnosis of posterior urethral valves.

Why do People Need Pelvic Ultrasound

Here are some situations where your doctor might use ultrasound imaging to better understand what’s going on in your pelvic region:

* It can help your doctor see normal organs in the pelvic region. These include the uterus, ovaries, and nearby structures.
* If your doctor feels a mass or lump during an examination, they might use an ultrasound to get more information. Common masses include large ovarian tumors, unusual shapes of the uterus that you might be born with (often noticed during pregnancy), and uterine fibroids, which are growths in or on the uterus.
* If you’re dealing with pelvic pain, an ultrasound can help identify its cause. Common culprits include pelvic inflammatory disease, ovarian torsion (when an ovary twists around its supportive tissues), ectopic pregnancy (when a fertilized egg implants somewhere outside of the uterus), and a normal pregnancy. Less commonly, the ultrasound might highlight conditions such as appendicitis, inflammatory bowel disease, or diverticulitis, where tiny, bulging pouches in the digestive tract get inflamed or infected.
* Ultrasound can also help diagnose the causes of abnormal vaginal bleeding. Such bleeding can be due to pregnancy, the menstrual period, precocious puberty (when a girl starts showing signs of puberty before age 8), and bleeding after menopause.
* It can also verify if an intrauterine device used for birth control is correctly positioned.

Your doctor might also use an ultrasound if he or she suspects you have polycystic ovarian syndrome or infertility. It can also check for ascites (buildup of fluid in the abdomen) or other free fluid.

For male patients, pelvic ultrasound can be used to check the prostate and seminal vesicles, parts of the male reproductive system. However, if the doctor is specifically looking for prostate cancer, they generally use a transrectal probe, which involves inserting a special ultrasound probe into the rectum to obtain a detailed view of the prostate.

Lastly, ultrasound can guide doctors in safely performing needle biopsies (where a small tissue sample is removed for testing) and aspirating (draining) free fluid.

While there aren’t any definite situations where using ultrasound (US) should be avoided, some circumstances might make it less suitable. For instance, the use of transvaginal ultrasound (TVUS), which involves inserting an ultrasound probe into the vagina, may not be the best choice during the late stages of pregnancy, or for patients who have a higher risk of health complications.

Equipment used for Pelvic Ultrasound

Ultrasound machines have different tools that help visualize the body structures. These tools, known as transducers, can be placed on the belly area (transabdominal) or inside the vagina (transvaginal). They operate at different frequencies (megahertz or MHz), which affect the image quality. Lower frequencies give better image of deep structures, while higher frequencies improve the image clarity of structures close to the surface. Typically, the probes used for belly scans work on lower frequencies than the ones used for vaginal scans.

Who is needed to perform Pelvic Ultrasound?

A sonographer or sonologist is a medical professional who specializes in using ultrasound machines to take images of your body’s organs and tissues. These images help your doctor understand what’s happening inside your body and make a diagnosis.

The interpreting physician is the doctor who examines these images. They use their medical knowledge and experience to find signs of health problems. They then use this information to decide on the best course of treatment for you.

Preparing for Pelvic Ultrasound

For doctors to get a clear view of the pelvic contents during a transabdominal ultrasound (a type of ultrasound where the probe is moved across the belly), it’s best if your bladder is full. However, if you’re having a transvaginal ultrasound (an ultrasound where the probe is inserted into the vagina), you don’t need to do anything special to prepare.

How is Pelvic Ultrasound performed

Ultrasound is a common imaging technique that physicians use to examine the body’s internal structures. There are several methods of performing ultrasounds in the abdominal and pelvic regions.

Transabdominal (TA) ultrasounds start by taking images in the middle of the belly, and then moving the imaging device to the edges of each half of the pelvis. The device is then moved from the middle of the bladder upward and downward to get images of the whole pelvis. If there isn’t much fluid in the bladder, which can often be the case with young children, the device can be placed on the side of the bladder and pointed towards the other side. This can help get more fluid in the image, providing a better view.

Transvaginal (TV) ultrasounds use a slightly different approach. Here, a specially designed imaging device is placed into the vagina (covered by a condom for hygiene) to get very detailed images of the uterus and its contents. This technique is very helpful for pregnancy-related imaging and also for studying the ovaries. The TV ultrasound method has been a game-changer in the examination of possible ectopic pregnancies since the late 1980s. Ectopic pregnancy is a potential life-threatening condition where a fertilized egg grows outside the uterus, often in a fallopian tube. The device used in TV ultrasounds operates at a higher frequency because it doesn’t need to go through a fluid-filled bladder or belly fat.

There are also several other ultrasound techniques available. For example, software can turn the typical black-and-white ultrasound images into three-dimensional images. These can be used to look at the vagina, cervix, and uterus in cases of developmental anomalies.

One less commonly used technique is transperineal imaging. Here, the imaging device is placed on the outer vaginal area, either going up and down or side to side. This method can be particularly useful for examining vaginal obstructions in patients who have not had sexual intercourse yet. It can also be used when there’s concern about the placenta covering the cervix (placenta previa) and an internal ultrasound isn’t advisable.

Doppler imaging is another ultrasound technique that can show blood flow in different parts of the body. For this imaging method, whether it’s regular color Doppler or power Doppler, cystic structures can be analyzed to assess their blood supply. Specific flow patterns and signals can point to abnormalities in blood vessels. However, while Doppler can reveal dilated or clotted blood vessels and blood flow to the ovary, its use is limited due to the ovary’s complex blood supply and thus, greyscale imaging is often more reliable for the diagnosis of conditions like ovarian torsion where the ovary twists, cutting off its blood supply. For examining the testicles, on the other hand, color Doppler can help in diagnosing when a testicle has twisted around (testicular torsion).

What Else Should I Know About Pelvic Ultrasound?

When doctors use an ultrasound to look at your pelvis, they can find out a lot of important information. For instance, they can check your uterus – the organ where a baby grows when a woman is pregnant. They can see its shape, size, and get a look at the endometrial cavity, which is the space inside the uterus. They can check if anything unusual is present inside.

Doctors can also examine your ovaries, which are the small organs on either side of your uterus that release eggs and hormones. By looking at the size and shape of your ovaries, doctors can check for any abnormalities, especially considering your age.

Ultrasounds work beyond just analyzing your uterus and ovaries. They can detect masses or growths in your adnexa, structures that are near your uterus like your fallopian tubes. They can also spot ovarian neoplasms (abnormal growths), evaluate them for size, shape, and if they’re changing over time.

For instance, they can identify “teratomas” (a type of tumor that can contain different kinds of tissues) on your ovary that may contain cystic (having small sacs filled with liquid or semi-solid material) and solid substances, or even bone-like or calcium deposits.

Apart from women’s reproductive organs, the ultrasound can evaluate the contents of your rectum, especially in babies or young children. They can identify if the walls of your bowel look thicker than usual, which could signal long-lasting (chronic) inflammation or even a tumor.

It can also help in spotting urethral cysts, especially in adult women. Your urethra is a tube that lets urine pass out of the body. In some rare cases, the ultrasound can even detect abnormalities in the structure of your pelvic bones.