Doppler artifacts and pitfalls.

With increasing technologic advances in ultrasound, its applications have continued to grow for the detection of pathology and physiology. To avoid misinterpretation of results, however, the Doppler US practitioner must understand the factors that produce a Doppler signal, whether vascular, motion, or artifact. Color or power Doppler artifacts can be verified by their atypical spectral waveform. Some artifacts, such as aliasing (for rapid detection of stenoses or arteriovenous fistulae) and the twinkle artifact (for identification of renal calculi and verification of other stones or crystals), are extremely useful diagnostically. Careful attention to the technical parameters of frequency, gain, filter and scale is required to correctly identify vascular patency or thrombosis, especially in slow-flowing vessels.