Methodology of gallbladder ultrasound

The ultrasound examination of the gallbladder is a whole complex of methods aimed at obtaining the most specific and reliable diagnostic data. There are recommendations, the observance of which allows the procedure to be carried out really effectively. The first condition is filling the gallbladder, which is achieved by fasting for at least twelve hours. The examination is most effective when the patient lies on his back, there are options when the patient is examined standing or lying on the left side. Depending on the plane, the scanning zone, the gallbladder in a normal state is visualized as an object of an elongated-rounded shape. The walls are not subject to visualization due to the fact that there is a transition zone of the liver parenchyma into the lumen of the bladder. The wall can appear as a signal with an average amplitude, this is especially typical when adult patients are examined, in children the picture is somewhat different. Behind the gallbladder (posterior wall), the echogram shows enhanced distal signals. There are cases when some darkening is observed in the echo-negative lumen, this is typical for the posterior wall zone. This phenomenon should not be confused with sediment, rather such a spot is explained by signal reverberation. If there are doubts, in such situations the patient is asked to turn over, stand up, in a word, change the position. An unchanged echo signal is an indicator of reverberation, if there is a shift in signals - sediment.

The ultrasound examination of the gallbladder assumes clear parameters of the normal limits depending on the patient's age. In children, these limits are expanded, but the diameter does not exceed 3.5 cm, the length parameters should not exceed 7.5 cm. The volume norms for children aged 5 to 12 years are no more than 200 ml. It should also be taken into account that it is quite difficult to differentiate the common and bile ducts on the echogram, therefore, in practice and interpretation of the results, specialists use the definition of "common bile duct". This duct runs in a parallel direction to the trunk of the portal vein, resembling a tube in structure. Sometimes a vascular branch related to the hepatic artery is visualized between the portal vein and the common duct. Dopplerography helps to clarify the picture. Normally, the common duct should be up to 8 millimeters wide, the average is from 4.1 to 4.5 millimeters. Bile ducts related to the intrahepatic space are normally not visualized, if they are visible, this indicates their expansion. Such indicators indicate possible cholestasis or the onset of icteric syndrome of mechanical etiology. In clinical practice, specialists conducting ultrasound identify 5 parameters by which it is possible to differentiate bile ducts visually:

• Changes related to anatomical features. This concerns the right side of the portal vein in the presence of small formations determined by the signal. As a possible sign, the phenomenon indicates that the intrahepatic bile ducts may be dilated (widened);
• The vessels are uniform, while the walls of dilated ducts are not uniform. Their direction is variable with a stable lumen;
• Formation of connections, fusions in the form of stars from the side of the bile ducts;
• Complete absence of echogenic signal from the ductal walls (the walls of the collar vein reflect the signal);
• The bile duct expands gradually, starting from the periphery, which is not typical for vessels.

The ultrasound examination technique of the gallbladder assumes that the patient is examined in a position that is comfortable for him and diagnostically comfortable for the examination process itself. As a rule, the patient lies on his back, holds his breath while inhaling. If the gallbladder is in a normal state, it is clearly visible, contoured, without the inclusion of abnormal structures. The typical location is the right quadrant of the upper part of the peritoneum. The organ size is from 5-6 cm to 8-9.5 cm, the transverse parameter should not be more than 3.5 cm. The wall is visualized as homogeneous, fairly thin (in the form of a line), the echogenicity is moderate. The contours of the organ are clearly visible, both external and internal. It should be taken into account that with age, the density of the wall may change, usually it increases. This is due to atrophy, decreased muscle tone, wear of the mucous membrane and the development of connective tissue. Sclerosis associated with age-related changes is visualized on ultrasound as increased density.

The initial stage of the study is the assessment of the gallbladder function, for which its size and volume are measured. The motor and evacuation capacity is assessed, and it is desirable to trace the cyclicity.

The ultrasound examination of the gallbladder may include both standard methods aimed at clarifying urgent situations, such as cholelithiasis (cholelithiasis), and longer-term ones, when a study is conducted to determine the functions of the organ. In any case, this type of diagnostics, regardless of the methods, is rightfully considered one of the most advanced in terms of reliability, effectiveness and safety.

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