In the last ten years, ultrasonography continues to gain importance thanks to ever-improving ultrasound technology using high-frequency probes and sophisticated software. With over a 90 percent of accuracy, ultrasonography is an excellent diagnostic tool, and not for breast cancer detection alone. It is especially powerful for interpreting benign breast changes and distinguishing them from malignant lesions, which often cannot be achieved with mammography, particularly in dense breast tissue. Ultrasound examination is therefore the first method of choice for women under 40 years of age, and also for those over 40 with dense breast tissue.
It operates within the principle of harmless, high-frequency sound waves that are translated into images by an appropriate computer software. Actually, sound waves pass through the breast tissue, bounce off various breast structures and reflect back to the probe that is cable-connected to the computer software for producing the ultrasound diagnostic image. As tissues vary in structure, the bounced-off sound waves are also of various distinguishing features. The examination technique is nonaggressive, i.e. it does not produce any tissue damage or involves no ionizing radiation.
Ultrasound breast examination may be performed for various purposes, although it is most often used to examine a specific breast region where there might be a problem. A palpable lump and/or shadow or tissue condensation detected on mammography can further be analyzed by ultrasonography. A special benefit of ultrasound is in its distinguishing fluid-filled cysts from solid lesions, i.e. lesions composed of solid tissue. As it has already been mentioned, ultrasound breast examination is frequently the first diagnostic test to identify breast changes in women under 35 years of age, whose mammograms are difficult to interpret because of their dense breast tissue. Recent studies have shown the advantage of ultrasonography over mammography in diagnosing for breast cancer in women under 45.
Due to the fact that no ionizing radiation is involved, ultrasound is an ideal diagnostic technique for pregnant women. It is also a reliable, accurate technique to check breast implants. Breast inflammations, such as inflammatory process or abscess, can be identified and followed up at ultrasound scanning. Thickened and edematous skin can be a sign of inflammatory breast cancer. Ultrasound can identify malignant growth within the breast causing the skin thickening. Such patients often undergo wide-needle aspiration biopsy or the so-called ‘core’ biopsy that is ultrasound-guided. Other interventions in the breast can also be ultrasound-guided, including aspiration of cyst fluid, fine-needle aspiration breast biopsy or the aforementioned wide-needle aspiration and marking of a change to be taken out at biopsy. Ultrasound can also precisely determine the spread of a breast process, or a healthy tissue involvement. Ultrasound breast examination is done on an outpatient basis in the doctor’s office or breast care centers. The examination is done on an adequate examination table. The patient should take off the clothes above the waist to allow examination of the breasts, armpits and the region above the collar bones.
The examination is performed either on the back-lying or on the side-lying position. During the procedure, the gel is applied to the skin as it is an indispensable amplifier of ultrasound wave transduction. Next, a probe, which sends sound waves through the tissue and receives back the waves bounced off the inner structures to transfer them to a video display screen, is placed on the gel-covered area. An ultrasound examination cannot be performed properly if the patient is not able to keep the required position. As the thickness or big breasts can blur the view of the inner structures, the accuracy of the examination mostly relies on the experience and judgment of the physician performing the examination. The image obtained depends on the wave penetration angle and breast compression during the imaging. The examination usually takes about 30 minutes, and yields the best results when performed within the recommended time frame, i.e. within the first ten days of the menstrual cycle when the breasts are less sensitive and feel less tense, and the influence of female sex hormones is not as profound as in the premenstrual period. If a change requiring cytologic verification is found during the examination, the procedure should rather be done in the first half of the menstrual cycle. However, as the ultrasound examination involves no ionizing radiation, there is nothing wrong if the examination is done at any time during the cycle.
The ultrasound test may reveal normal breast tissue or detect benign changes, including simple cysts that produce no symptoms and do not require any further treatment except for a regular follow-up. Such findings are interpreted as normal. On the other hand, pathological findings can be classified into one of the following categories: benign fibrous lumps, complex cysts, suspicious lesions or lesions very suggestive of cancer. If the ultrasound scan reveals a complex cysts or a benign fibrous lump, a cytopuncture and/or biopsy and pathohistologic evaluation of the biopsy specimen should be done as 10%-15% of such tumors turn to be of a malignant nature. A significant proportion of lesions that fall within the latter two categories may be cancer and therefore require additional treatment, including a biopsy or surgery. Breast cancer, however, is not a unique entity.
There are several different types of breast cancer that may present differently on ultrasound, and the most common are as follows: ductal, lobular, medullary, mucinous, tubular, and papillary breast cancer. Based on their ultrasound morphology, such as their shape and margins, malignant breast changes can sometimes be clearly distinguished from benign, but, of course, there is an exception to every rule. For instance, benign fibroadenoma is usually an oval lump, but some cancers may also be of a similar shape. Malignant changes usually have a scalloped peripheral margin, but a similar margin pattern may also be characteristic of some benign changes. In such cases, ultrasound diagnosis is not definitive. Hence, further evaluation of the tissue specimen is required to make an accurate and unambiguous diagnosis. Some of these issues may be resolved by supplemental, more invasive ultrasound-guided techniques, and some may require a more extensive procedure, including surgical biopsy for example. Which of the diagnostic procedures is the best is always left at discretion of the physician performing the ultrasound breast examination and making the final decision based upon the findings. At our Polyclinic, fine experts covering this particular specialist field and dealing exclusively with it in their everyday practice perform ultrasound examinations using the newest generation of ultrasound technology.
