1\ Kidney Scanning

1.1.1\ Scanning Method

The patient lies flat or on the left side. The transducer is placed at the right posterior axillary line, the ninth or tenth intercostal space in a coronal

approach. Anterior to the right kidney lies the liver, which offers a sonic window. If the upper pole is not imaged clearly, the patient could be told to hold a deep inspiration to have the organs moving down.

1.1.2\ Section Structure

Coronal section of the right kidney, which includes the renal capsule, renal parenchyma, and renal sinus, and the oblique section of the right lobe of the liver are shown in this view. The renal parenchyma is composed of cortex and medullary pyramid. The cortex can be divided into the peripheral portion and the columns of Bertin, which extend between the medullary pyramids. The medulla consists of the pyramids, which are called renal pyramids, and has lower echogenicity than the renal cortex. These pyramids line radially and their tips point to the renal hilum. The renal hilum, an irregular area with slightly higher echogenicity, is continuous with a central cavity called the renal sinus which includes the major branches of the renal artery, major tributaries of the renal vein, the collecting system (renal pelvis, renal calices), and fat.

1.1.3\ Measuring Method and Normal

The kidney is about 10–12 cm long, and the cortex is about 1.0 cm thick measured in this view.

Width of the renal pelvis, as an anechoic area, can also be observed.

1.1.4\ The Clinical Application Value

The diffuse lesion, space-occupying lesion, deformity, calculus of the kidney, and hydronephrosis can be diagnosed in this view. Origins of the space-occupying lesions in the right upper abdomen can also be differentiated from this section.

1.1.5\ Notice

Hypertrophied column of Bertin (HCB) is a normal variant that should be differentiated from the solid masses of the kidney. The former has the same echogenicity as the renal cortex and is continuous with the adjacent cortex, while most of the latter have borders and different echodensity with the adjacent renal parenchyma. Renal calices may be imaged as anechoic areas which are required to be differentiated from renal cysts. The former are generally multiple, irregular, and surrounding and connecting the renal pelvis in line, while the latter do not connect the renal pelvis.

1.2.1\ Scanning Method

The patient lies in supine position or on the left side. The transducer is placed at the right posterior axillary line, the ninth or tenth intercostal space in a transverse approach, with the probe moving up and down.

1.2.2\ Section Structure

Transverse planes of the kidney and renal hilum are shown. Anterior to and posterior to the right kidney lie the right lobe of liver and the great psoas muscle, respectively.

1.2.3\ Measuring Method and Normal

Posterior-anterior dimension and width of the kidney are measured in the view. The normal values are 3–4cm and 5–6cm respectively.

1.2.4\ The Clinical Application Value

It is more clear to show the lesions, such as cysts, locating the subcapsule of the kidney or processing the renal capsule in this plane than in the longitudinal plane of the kidney. Lesions of the great psoas muscle and renal hilum can also be imaged.