Biomed Eng Lett (2014) 4:41-54 DOI 10.1007/s13534-014-0124-4 Color Doppler Twinkling Artifact: Possible Mechanisms and Clinical Potential Min Joo Choi, Chang Hee Cho, Gwansuk Kang and Jeonghwa Yang Received: 20 March 2014 / Accepted: 23 March 2014 © The Korean Society of Medical & Biological Engineering and Springer 2014 Abstract In the color Doppler mode of ultrasonography, a rapidly changing mixture of red and blue colors referred to as ‘twinkling artifact’ (TA) may appear for a stationary hyper- echogenic target. This introduces ambiguity in diagnosis as well as provides conclusive information. We reviewed the possible mechanisms, and also illustrated the clinical potential in the detection of pathological sites associated with calculi, calcifications, cacinoses and fibroses and foreign bodies such as surgical clips, catheters, and guiding needles which were inconclusive in conventional grayscale sonograms. In order to increase the clinical utility of TA, a practical means to enhance TA was suggested which leads to a ‘TA mode’ to be implemented in a clinical scanner. Keywords Color Doppler, Twinkling artifact, Echogenic target, Mechanism, Clinical potential INTRODUCTION Color Doppler sonography is commonly used to evaluate the characteristics of moving objects within the body such as vascular blood flow [1]. The imaging technique has been expanded to moving tissues, leading to ‘tissue Doppler image’ [2]. Two colors (red or blue) in the color Doppler image indicate the directions of the blood flow or tissue movements and the color intensity signifies the extent of flow or movement. In the color Doppler image for objects that neither flow nor moving, we often observe a rapidly changing mixture of red and blue colors. This ‘twinkling sign’ commonly appears behind a strong reflector with rough structures as it is first mentioned in a color Doppler image for urolithiasis by Rahmouni et al. [3]. In many cases, the twinkling sign has a shape of comet tail and it is sometimes referred to as ‘color comet-tail artifact’ [4, 5]. Nowadays ‘twinkling artifact’ (TA) is taken as the most frequently used terminology to cover twinkling sign, color comet-tail artifact, or twinkling colors. The underlying mechanisms for TA occurring at the stationary objects are not clearly known. It is understood that the TA is associated with targets [6-10] and ultrasonic scanners [11]. It has been reported that TA appears behind a strong reflector such as calculi, calcifications, calcinosis, and foreign bodies (guiding needles, catheter, and surgical clips) [3, 10, 12]. TA depends on color Doppler setting parameters such as color write priority (CWP), Gain, pulse repetition frequency (PRF), wall motion filter (WMF), Ensemble number, focal location and so forth. The acoustic power output from an ultrasonic scanner may also influence on TA. In fact, a new digital scanner tends to employ higher acoustic power and generates TA more easily than conventional analogue scanners [4]. TA may lead to misdiagnosis of vascular flow within a tissue or moving tissues. Accordingly it is important to differentiate Min Joo Choi Department of Medicine, School of Medicine, and Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, 102 Jejudaehakno, Jeju-Si, Jeju Special Self-Governing Province, 690 756, Republic of Korea Chang Hee Cho School of Medicine, Jeju National University, 102 Jejudaehakno, Jeju-Si, Jeju Special Self-Governing Province, 690 756, Republic of Korea Gwansuk Kang Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, 102 jejudaehakno, Jeju-Si, Jeju Special Self-Governing Province, 690 756, Republic of Korea Jeonghwa Yang ( ) Department of Radiotechnology, Cheju Halla University , 38 halla daehak- ro, Jeju-Si, and Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, 102 jejudaehakno, Jeju-Si, Jeju Special Self-Governing Province, 690 756, Republic of Korea Tel : +82-10-5394-7888 / Fax : +82-64-702-2687 E-mail : Julie87@hanmail.net REVIEW ARTICLE