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Ultrasound signs of normal kidney and ureter
Last reviewed: 19.10.2021
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US of normal kidney signs
The measurements carried out during the ultrasound study are generally of lower values than the same parameters obtained by X-ray diffraction: they are more accurate.
Both kidneys should have approximately the same size in adults, the difference in the length of the kidneys by more than 2 cm is pathological.
- Length: up to 12 cm and not less than 9 cm.
- Width: Normal is the width of 4-6 cm, but may vary slightly depending on the scanning plane.
- Thickness: up to 3.5 cm, but may vary slightly depending on the scanning plane.
- The central echocomplex (renal sinus) has a high echogenicity and normally takes about 1/3 of the kidney. (Renal sinus includes the pelvis, cups, vessels and fat.)
In newborns, the kidneys have a length of 4 cm and a width of 2 cm.
Kidney pyramids are hypoechoic zones with fuzzy boundaries: in the projection of the medullary layer, the pyramids are surrounded by a more echogenic kidney bark. It is easier to visualize pyramids in children and young adults.
When examining the kidneys, the following structures should be identified:
- Kidney capsule. It is visualized as a bright, even echogenic line around the kidney.
- Cora. It is slightly less echogenic. Than the liver, but more echogenic than the adjacent kidney pyramids.
- Medullary layer. It contains hypoechoic kidney pyramids, which can be mistaken for kidney cysts.
- Renal sinus (fatty tissue, collecting system and vessels of the kidney gate). This is the inside of the kidney, it has a high echogenicity.
- The ureters. Normal ureters are not always visible: one can only assume where they exit from the kidney in the gate area. They can be single or multiple, often visualized in the frontal section.
- Renal arteries and veins. It is better to visualize in the gate area. They can be multiple and can enter the kidney at different levels.
A warning. Kidney pyramids can be mistaken for kidney cysts and tumors. Adjust the sensitivity level of the instrument.
Ultrasound signs of the adrenal glands
The adrenal glands are not easily visualized by ultrasound. The best position of the patient on the back, while scanning, as in the study of the inferior vena cava and the patient's position on the side (thus obtained sections in the frontal plane). The adrenal glands are located higher and medial than the kidneys. If they are visualized, it is most likely that they are pathologically enlarged, with the exception of the adrenal glands in infants.