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Ureter Ultrasound and Sonography Classification of Hydronephrosis

The indications for ultrasonography of the ureters are comparable to the indications for renal ultrasound (see section renal ultrasound).

Ultrasound examination of kidney and ureter: hydronephrosis with dilatation of the renal calyces and pelvix without signs of organ atrophy. With kind permission, Dr. med. A. Passon, Augsburg.

Examination Technique

The transducer used for ureter ultrasonography is a sector or curved array probe with 3.5–5 MHz. The examination of the ureters is done in supine position and with inspiration of the patient. In case of unfavorable conditions, a lateral decubitus position is helpful, whereby the side to be examined is raised by 30\textdegree. The kidney is used as an acoustic window, the renal pelvis and the ureteral outlet can be visualized regularly. Intestinal air often prevents the examination of the proximal ureter, the mid portion cannot be examined with ultrasound. The distal part of the ureter is examined in supine position and with full bladder, the bladder is used as an acoustic window.

Hydronephrosis:

The distinction between hydronephrosis or significant urinary tract obstruction is not possible with sonography. The dilatation of the upper urinary tract is classified according to morphological criteria [fig. classification of hydronephrosis]. Consequently, hydronephrosis should be described in the ultrasonography report without judging the significance of the obstruction (Beetz u.a., 2001).

Graduation of hydronephrosis in ultrasonography (Beetz u.a., 2001): longitudinal plane (top row) and horizontal plane (bottom row).
Grade I: echo-free dilatation of the renal pelvis without enlargement of the renal calyces. Clear hyperechoic reflex pattern of the renal sinus and no signs of organ atrophy.
Grade II: echo-free dilatation of the renal pelvis and calyces. Attenuated ultrasound reflex pattern of the renal sinus. No signs of parenchymatous atrophy (prominent papillary impression and sharp-edged calyces).
Grade III: prominent echo-free dilatation of the renal pelvis and the renal calyces. Missing or marginal imaging of the renal sinus. Signs of organ atrophy: flattening of papillae and blunting of calyces.
Grade IV: massive echo-free dilatation of the renal pelvis and renal calyces, loss of borders between renal pelvis and calyces. Almost complete atrophy of the renal parenchyma (hydronephrotic sac).

References

  Deutsche Version: Sonographie der Harnleiter