Methodology of ultrasound of the gallbladder

The technique of ultrasound of the gallbladder is a whole complex of methods aimed at obtaining the most specific and reliable diagnostic information. There are recommendations, observance of which allows to carry out the procedure really effectively. The first condition is the filling of the gallbladder, which is achieved by fasting for at least twelve hours. The examination is most effective when the patient lies on the back, there are options when the patient is examined standing or lies on the left side. Depending on the plane, the scanning zone of the gallbladder in the normal state is visualized as an object of elongated-round shape. The walls of visualization are not subject to the fact that there is a zone of passage of the liver parenchyma into the zone of the lumen of the bladder. The wall can appear as a signal with an average amplitude, especially when adults are examined, children have a slightly different picture. Behind the gall bladder (posterior wall), the echogram shows enhanced distal signals. There are cases when in the echo-negative lumen there is some darkening, this is typical for the zone of the posterior wall. This phenomenon should not be confused with precipitation, rather a similar stain is explainable by the reverberation of the signal. If in doubt, in such situations, the patient is asked to turn over, stand up, in short, change the position. A constant echo signal is a reverberation index, if there is a signal bias - a precipitate.

The technique of ultrasound of the gallbladder assumes clear parameters of the norm limits depending on the age of the patient. In children these borders are widened, but the diameter does not exceed 3, 5 cm, the length parameters should not exceed 7.5 cm. The norms of the volume of children from 5 to 12 years are not more than 200 ml. It should also be taken into account that it is rather difficult to differentiate the common and bile ducts on the echogram, therefore, in the 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, reminiscent of the structure of the tube. Sometimes, between the portal vein and the common duct, a vascular branch that belongs to the hepatic artery is visualized. Dotplerography helps to clarify the picture. Normally, the total duct should be a width of up to 8 millimeters, the average value is from 4.1 to 4.5 millimeters. Bile ducts related to the intrahepatic space are not normally visualized, if they are viewed, this indicates their expansion. Such indicators indicate a possible cholestasis or the beginning icteric syndrome of mechanical etiology. In clinical practice, specialists conducting ultrasound, identify 5 parameters, according to which it is possible to differentiate the bile ducts visually: 

• Changes associated with anatomical features. This is true of the right side of the portal vein in the presence of small formations, defined by the signal. As a possible sign, the phenomenon indicates that the intrahepatic bile ducts may be dilated (dilated); 
• Vessels are distinguished by their uniformity, in contrast to them the walls of dilated ducts are not distinguished by their evenness. Their directionality is variable with stable lumen; 
• Formation of compounds, fusions in the form of stars from the bile duct; 
• Complete absence of echogenic signal from the flow walls (walls of the collar vein reflect the signal); 
• The bile duct dilates gradually, starting from the periphery, which is not characteristic for blood vessels.

The technique of ultrasound of the gallbladder suggests that the patient is examined in a position convenient for him and diagnostically comfortable for the survey process itself. As a rule, the patient lies on his back, holds his breath on inhalation. If the gallbladder is in a normal state, it is clearly visible, contoured, without the inclusion of abnormal structures. A typical arrangement is the right quadrant of the upper part of the peritoneum. The size of the body 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, thin enough (in the form of a line), echogenicity is moderate. The contours of the organ are clearly visible both external and internal. It should be taken into account that the density of the wall may change with age, it usually rises. This is due to atrophy, decreased muscle tone, mucosal wear and the development of connective tissue. Sclerotherapy associated with age-related changes is visualized by ultrasound as an increased density.

The initial stage of the study is the assessment of the function of the gallbladder, for which the measurement of its size and volume is carried out. Estimated motor and evacuation ability, while it is desirable to track the cyclicity.

The technique of ultrasound of the gallbladder can include both standard methods aimed at clarifying urgent situations, for example, such as cholelithiasis (cholelithiasis), so longer in time when research is conducted with the definition of organ functions. In any case, this type of diagnostics, regardless of the methods, is rightfully considered one of the most perfect in reliability, effectiveness and safety.

[1], [2], [3], [4], [5]