Ultrasonography (US) is the primary modality for assessing the contents of the female pelvis. It enables quick (and portable) imaging of the uterus, ovaries, and other structures at a low cost and without the use of ionizing radiation. Irradiation should be avoided because the ovary is especially vulnerable to radiation in patient populations and those of reproductive age.
Pelvic ultrasound is performed either transabdominal (TA) or transvaginal (TV). The gel is applied to the skin above the bladder to allow transducer contact without the presence of air on the skin’s surface. A urine-filled bladder aids in the superior lifting of the small bowel out of the pelvis, resulting in an ideal sonic window and preventing bowel air from diffracting or degrading the ultrasound beam. The US moves freely through the pelvic fluid, insonating pelvic contents and returning to the transducer to be analyzed by the system.
Ultrasound is an important tool for assessing the contents of the female pelvis. It enables low-cost imaging of the uterus, ovaries, and other tissues without the use of ionizing radiation or contrast. Because the ovaries are particularly vulnerable to radiation, the absence of radiation is critical. This activity describes the pelvic ultrasound technique, indications, and contraindications. This activity emphasizes the interprofessional team’s role in the care of patients undergoing pelvic ultrasounds.
UNDERSTANDING THE ANATOMY OF THE FEMALE BODY
UTERUS / CERVIX
Ultrasound of the uterus and cervix is of utmost importance as many infections are indwelling there. Negligence to hygiene can cause bacterial infections and this can also lead to lethal diseases like cervical cancer or the formation of leiomas or fibroids.
If the uterine endometrial cavity is obstructed, the contents may have varying echogenicity (e.g., from cervical stenosis in an older woman status post radiotherapy or a child with hematometrocolpos). Otherwise, the walls are covered, and the endometrial lining is viewed with a different echogenicity than the remainder of the uterus, which varies depending on hormone levels, patient age, and menstrual cycle stage.
Ovaries are typically almond-shaped along with the attachment to the fallopian tube. In an ovarian scan, you can understand the presence of follicles and this may vary with age and hormonal balance, time in the menstrual cycle. If the ovaries are inflamed this might indicate pelvic inflammatory disease.
While scanning the pelvis other structures are also been scanned, This can also be useful. As the abdomen contains excess fluid underlying pathologies can be diagnosed with the help of ultrasonography. Pathologies like hernias, appendicitis, diverticulitis, and gastrointestinal malignancy such as appendiceal mucoceles can also be visualized at times.
WHEN TO UNDERGO A ULTRASONOGRAPHY?
- The typical pelvic contents, including the uterus, ovaries, and adnexal tissues, are examined.
- Physically palpated masses can be assessed further by the US.
- Large ovarian tumors, congenital uterine shape anomalies (frequently observed during pregnancy), and uterine fibroids are among the most commonly palpated masses.
- The US can examine patients who report pelvic pain. Pelvic inflammatory illness, ovarian torsion, ectopic pregnancy, and normal pregnancy are all common diagnoses. Appendicitis, inflammatory bowel illness, or diverticulitis are identified less frequently with pelvic ultrasound.
- Abnormal vaginal bleeding can be caused by a probable pregnancy, a confirmed pregnancy, menstruation, precocious puberty, or postmenopausal bleeding.
- An intrauterine device is evaluated for proper placement. Polycystic ovarian syndrome and infertility evaluation. US can be used to demonstrate ascites or other free fluid.
- Pelvic ultrasound can examine the prostate and seminal vesicles in male patients. A transrectal probe is the finest way to examine the prostate, especially when looking for cancer.
- The US can be used to help with needle biopsies and the aspiration of free fluid.
WHAT IS THE EQUIPMENT USED FOR ULTRASONOGRAPHY?
US computer with adjustable frequency transabdominal (TA) and transvaginal (TV) transducers (MHz). Lower frequencies provide greater penetration. Higher frequencies enable improved near-field resolution. TA probes have a lower frequency than TV probes. The technicians required in order to carry out this process are;
- Sonographer or sonologist.
- Interpreting physician.
A urine-filled bladder is ideal for viewing pelvic contents with the TA method. There is no special preparation necessary for TV imaging.
TECHNIQUES USED WHILE PERFORMING ULTRASONOGRAPHY
Transabdominal imaging is often composed of midline sagittal and parasagittal images angled from the midline to the periphery of both hemipelves. Transverse plane scans begin at the bladder’s midline and angle superiorly and inferiorly to image the pelvis.
If there isn’t enough fluid in the bladder, particularly in young children, the transducer can be placed over the lateral aspect of the bladder and guided to the contralateral side for imaging. This provides more fluid for the US beam to traverse and a better working acoustic window.
When compared to regular TA imaging, TV scans use elongated transducers with higher frequency elements in the region of 7 MHz to 8 MHz (near 3.5 MHz). The transducer is inserted into the mid to upper vagina (wrapped in a condom) to provide coronal and sagittal images that enable high-resolution imaging of the uterus and its contents, which is useful in obstetrical imaging as well as the study of the ovaries and adnexa.
TV US, which debuted in the late 1980s, transformed the analysis of the presence or absence of ectopic pregnancy. Because there is no need to traverse a fluid-filled bladder or anterior abdominal wall fat, a higher-frequency TV transducer can be employed.
Many US machines have postprocessing software that allows the three-dimensional reconstruction of ordinary greyscale ultrasound pictures to create surface and volumetric images. For Mullerian Duct system malformations, this procedure has been utilized to repair the vagina, cervix, and uterus.
Transperineal imaging, which involves placing a transducer on the labia in the longitudinal or transverse plane, is sometimes used to assess the vagina and uterus. This has enabled the investigation of vaginal blockages, particularly in virgin patients. It has been used to detect placenta previa when an intravaginal probe is not available.
Cystic formations can be assessed for vascularity using standard color Doppler or power Doppler imaging. Color Doppler clearly shows iliac vascular flow, which is frequently in a plane posterior to the ovaries. Spectral Doppler can be used to examine vessels for anomalies in venous or arterial flow signals.
Pseudoaneurysms, while uncommon in the pelvis compared to the groin, may exhibit the classic neck of the lesion with yin-yang colour flow pattern. When assessing the existence or degree of vascular flow, power Doppler can be used in instances where color Doppler may be inadequate (very low or slow flow).
WHY IS ULTRASONOGRAPHY IMPORTANT?
When using ultrasound to image the pelvis, a lot of clinically important information is obtained. This covers information about the uterus, its shape, size, endometrial cavity characteristics, and contents. Identification and examination of the ovarian size and morphology aid in determining if there are any ovarian anomalies at a specific age. US can detect masses other than the uterus and ovaries, such as adnexal cysts.
Ovarian neoplasms can be measured in terms of size, shape, and growth over time. Ovarian teratomas with their typical cystic and solid (Rokitansky nodule) components, such as bone or calcium, may be included. Rectal contents can be assessed, particularly in newborns and early children. Thick gut walls caused by chronic inflammation or tumor may be observed on occasion.