Stone/Hydronephrosis

Non-contrast CT for renal colic.
Left Image: shows right-sided pelvicaliectasis relative to the left-sided renal collecting system.
Right Image: shows calculus in the distal right ureter as the cause.
[Courtesy of Dr. N. Jaffer]

Hydronephrosis of left kidney on ultrasound caused by a left upper ureteric stone seen on abdominal X-ray (red arrow).