Obstructing Ureteric Stone on Ultrasound

Figure 1: A gray-scale ultrasound image of the right kidney shows right hydronephrosis and hydropelvis.

Figure 2: The scan in the right pelvis demonstrates an echogenic focus (arrow) with posterior acoustic shadowing (arrowheads) at the site where the ureter abruptly changes its caliber.

Facts:

• Imaging in patients presenting with renal colic is performed to 1) confirm the suspected renal colic, 2) diagnose cause and level of obstruction, 3) detect or rule out complications of renal colic (obstruction, infection), 4) detect alternative diagnoses
• Non-contrast CT is current gold standard for diagnosis of urinary tract stone disease
• Ultrasound may be an initial imaging done although its sensitivity is limited (37% - 64%) for detecting renal calculus (lower for ureteric calculus) and acute obstruction (74% - 85%)

Imaging Appearance

• Stone (brightly echogenic focus with posterior acoustic shadowing). For renal stone less than 5 mm, ultrasound is of limited accuracy. Ureteric stone is uncommonly appreciated on US.
• Hydronephrosis
• Twinkling artifact behind the stone, and absent ureteral jet on color Doppler imaging

Reference:

Scott LM, Sawyers SR, Bokhari J, Hamper UM. Ultrasound evaluation of the acute abdomen. Ultrasound Clin 2007;2:493-523.