A 38 year old woman presents with midcycle LIF pain. It is colicky and you are asked to scan her pelvis.
View 2: Transverse Bladder
View 3: Left mid ureter
View 4: Left mid ureter with colour Doppler
Describe and interpret these scans
Image 1: Left kidney. Normal left kidney with no hydronephrosis.
Image 2: Transverse Bladder. Normal left ureteric jet; this excludes a completely obstructing ureteric calculus, but sometimes a stone does not cause complete ureteric obstruction.
Image 3: Left mid ureter. The ureter crosses the iliac vessels at the pelvic brim. A 5mm echogenic shadow casting lesion is seen within the lumen of a slightly distended ureter. The cause of her pain is ureteric colic.
Image 4: With colour Doppler the vessels are interrogated. Flow is demonstrated in the iliac vessels, not in the ureter, and the stone demonstrates “twinkle” artefact.
Left ureteric colic
Renal stones generally cause symptoms when they pass into the ureter. They are known to get stuck at three points – the pelvi-ureteric junction (PUJ), the mid ureter at the pelvic brim as the ureter crosses the iliac vessels, and distally at the vesico-ureteric junction (VUJ).
In this case the stone is seen at the mid ureter.
Ultrasound technique: I always search for the mid ureter in patients with suspected renal colic. With the probe placed in the saggital plane I slide the probe along the iliac vessels from origin to groin. A dilated ureter will be seen as a hypoechoic tubular structure running obliquely over the iliac vessels at their mid point. A non dilated normal ureter is usually not seen.