Methods of breast ultrasound

To assess the localization of pathological processes, the mammary gland is divided into:

• supramammal, submammal segments and the areola region;
• four quadrants (upper outer, lower outer, lower inner, upper inner) and the areola;
• sectors similar to the numbers on a clock dial (09:00, 12:00, etc.).

When starting to master ultrasound examination of the mammary glands, it is necessary to adopt the same sequence of examination of the mammary glands from the very beginning. Echography is performed with the patient lying on his back, with a comfortable position of the head, arms lowered along the body. The examination of the right gland begins with the upper outer quadrant, then the lower outer, lower inner are examined in turn, and finish with the upper inner quadrant. The left mammary gland is examined starting from the upper inner quadrant counterclockwise, finishing the examination in the upper outer quadrant. Compliance with a certain sequence of sensor movement allows you to avoid any parts of the mammary glands falling out of the field of view in the future. The mammary glands are examined by moving the sensor from the outer parts of the gland to the nipple or in the opposite direction. Such movement of the sensor corresponds to the anatomical location of the glandular lobes and milk ducts. The nipple and areola are examined using a large amount of gel or with a silicone pad or water attachments. The sensor is moved along the main axis of the milk ducts from the nipple to the periphery of the organ. For better visualization of the retro-nipple area, additional compression is performed with the sensor and not only standard straight but also oblique cuts are used. The examination of the mammary glands is completed by analyzing the state of the regional lymph drainage zones.

To standardize the examination of patients with pathological changes in the mammary glands, according to the scheme proposed by Pickren, ultrasound landmarks of three zones for searching for pathologically changed lymph nodes are identified. The axillary zone is from the lateral border of the pectoralis minor muscle to the lateral edge of the axillary region. Its landmark is the axillary vein and the external thoracic artery. The subclavian zone is from the lower edge of the clavicle to the medial border of the pectoralis minor muscle. Its landmark is the subclavian artery. The supraclavicular zone is from the upper edge of the clavicle to the medial edge of the digastric muscle. Its landmark is the thoracoacromial vein. We supplemented this scheme with an examination of the anterior thoracic zone from the lower edge of the clavicle along the midclavicular line (along the pectoralis minor muscle) to the border with the mammary gland. This completes the overview (screening) stage of the examination of the mammary glands, during which the following are assessed:

1. the condition, quantity and nature of distribution of the stroma, glandular structures, milk ducts and adipose tissue;
2. clarity of differentiation of mammary gland tissues (with an indication, if necessary, of the reason for their poor detail);
3. disturbances in the architecture of the mammary glands, classifying them as diffuse or focal (their location and size are described).

All changes found in one mammary gland are compared with symmetrical areas in the contralateral mammary gland. Finally, the state of regional lymph drainage zones is necessarily assessed.

At the stage of clarifying ultrasound mammography, the sensor is returned to the area of atypical tissue structure. In this case, the state of the contours, visualization of the anterior and posterior walls, and the presence of additional acoustic effects are determined. The internal echostructure of changes and the state of adjacent tissues are necessarily assessed. The tissue image is assessed not only in the normal mode, but also with additional compression of the mammary gland tissues (in the "compression" mode). When pressing the sensor on the skin lubricated with gel, due to the compaction of the structures, the thickness of the tissues between the sensor and the area of interest decreases, visualization of deep-seated formations improves, and the severity of lateral shadows-artifacts from the gland's own tissues decreases. In addition, the compression mode allows you to obtain additional information about changes in the shape of the formation, internal structure, and relationships with surrounding tissues.

The internal structure of benign formations becomes more homogeneous and ordered when compressed, the shape changes more often (flattens), the contours are visualized more clearly. Malignant formations are not characterized by changes in shape and internal architecture when compressed.

The shaking technique is used to determine the displacement of the internal contents. The formation is fixed between the thumb and index finger of the left hand and is shaken from side to side. The sensor is positioned above the formation, and changes occurring in the formation are assessed on the monitor screen.

At the same time, the displacement of the formation relative to the surrounding and underlying tissues is assessed to determine the nature of the growth of the formation (infiltrative or expansive).

When pathological changes are detected, they are assessed in two mutually perpendicular planes. This approach allows for measurements of three parameters (width, thickness and length) and correlation of echographic findings with X-ray mammography results and morphological data.

If the mammary glands are large, the examination is carried out with the patient lying on his side, sitting, standing, with his hands raised behind his head.

To compare the echographic data with the data obtained during X-ray mammography (especially in women with large mammary glands), the examination is carried out in a sitting position. In this case, the mammary gland is placed with its lower surface on the table (or lifted by the patient's hand). During the examination in this position, the tissues are flattened between the sensor and the table surface, which imitates the standard craniocaudal position for X-ray mammography. If a malignant process in the gland is suspected, it is necessary to assess the condition of the target organs. Taking into account the peculiarities of the lymphatic drainage of the mammary gland, these include the liver, ovaries and inguinal lymph nodes. In some diseases, for example, in case of dyshormonal processes in the mammary gland, in order to determine their cause, it is necessary to visualize and determine the functional state of the thyroid gland.

To improve the accuracy of ultrasound examination after assessing the mammary glands in B-mode, it is advisable to use Dopplerography of the mammary gland vessels to obtain a Doppler spectrum, color Doppler mapping, and energy Dopplerogram.

The resistance index (RI) and pulsation index (PI) are most frequently used to characterize benign and malignant changes in the mammary glands. According to Medl and Konishi, the resistance index is the most important. When assessing the resistance index, the sensitivity of duplex Doppler sonography in detecting breast cancer is 84%, and the specificity is 80%. According to Lee, the appearance of signals from vessels (both inside and along the periphery of a volumetric formation of the mammary gland) during color Doppler mapping is interpreted as a sign of malignancy.

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