9 Kidneys

Kidneys 321

Constitutional/Acromegaly

Duplex Kidney, Single Kidney

Diabetic Nephropathy

Polycystic Kidney Disease

Acute Renal Failure,

Shock Kidney

Septic–Toxic Kidneys

Acute Urinary Retention,

Acute Outflow Obstruction

Renal Congestion Due to Heart Failure

Renal Vein Thrombosis

Acute Glomerulonephritis

Acute Pyelonephritis

AIDSand Heroin-induced

Nephropathy

Amyloidosis/Paraprotein Kidney

Pyonephrosis

Renal Tumor

Renal Allograft,

Allograft Rejection

Hypoplasia

Renal Artery Stenosis, Embolism

Arteriosclerosis, Arteriolosclerosis

(Ischemic Nephropathy)

Chronic Pyelonephritis

Analgesic Nephropathy

Chronic Glomerulonephritis

Diabetic Nephropathy

Cortex. The renal cortex is a strip 6–10 mm wide located just beneath the fibrous renal capsule. Its boundary is formed by an imaginary line along the bases of the medullary pyramids. Extensions of the renal cortex, called the renal columns, extend between the 7–9 pyramids that make up the renal medulla. The renal

calices. Because of the high fluid content of the collecting ducts, the medullary pyramids appear markedly less echogenic in ultrasound than the renal cortex (Fig. 9.1).

Vessels. The vessels of the kidney, the renal artery and vein, divide into an anterior and a posterior branch at the renal hilum while still

the interlobular arteries, which pass radially into the renal cortex. The individual vessels are displayed particularly well by color Doppler sonography (CDS). The veins run parallel to the named arteries. The entire vascular system is also clearly visible in 3 D imaging.

Fig. 9.1 Renal cortex and medulla.

aDiagram showing the medullary pyramids, vessels, and

amalpighian corpuscle.

b Close-up view of the right kidney, showing the relatively hypoechoic medullary pyramids (MP) and the cortex (R), bounded by an imaginary line connecting the bases of the pyramids. Between the medullary pyramids are the renal columns (CO).

Fig. 9.2 Radial branching of the segmental arteries into the interlobar vessels. Left kidney (enlarged following a right nephrectomy). AR = renal artery; VR = renal vein.

f Fig. 9.3 Detail view of a medullary pyramid (MP) with the surrounding interlobar vessels, which turn horizontally at the bases of the pyramids to form the arcuate vessels.