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Twinkling artifact - renal stone

Case contributed by Ammar Haouimi
Diagnosis almost certain

Presentation

Left renal colic.

Patient Data

Age: 60 years
Gender: Male
ultrasound

Left renal stone is seen as an echogenic focus with posterior acoustic shadowing. The color Doppler shows an alternating colors signal behind the stone giving the appearance of turbulent blood flow in keeping with twinkling artifact. No dilatation of the renal cavities.

The right kidney and urinary bladder were normal (not shown).

Case Discussion

Twinkling artifact is more sensitive for the detection of small stones (e.g. urolithiasischolelithiasis) than acoustic shadowing. The presence of renal twinkling artifact on ultrasound exam has a high positive predictive value (78%) for the presence of nephrolithiasis on unenhanced CT.

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