Color Doppler Artifact Research Articles

Gebelikte Venöz Akımda Blooming Artefaktının Değerlendirilmesi için Üç Farklı Renkli Doppler Tekniğinin Karşılaştırılması

Aim: Blooming is an important color Doppler artifact for the assessment of small or slow-flow blood vessels during pregnancy. The degree of blooming varies depending on the color Doppler technique used. The purpose of our study is to compare doppler techniques related to the flowering artifact so that the imaging method closest to the actual size of small vessels can be selected. Method: A total of 100 pregnant women were included in this study. The diameter of the intrahepatic umbilical vein was measured using three different color Doppler techniques: conventional color Doppler (CCD), power Doppler (PWD), and advanced dynamic flow (ADF). Blooming was assessed by comparing the diameter of the vessel in B-mode and in color Doppler mode. Results: Results: The diameter of the intrahepatic umbilical vein measured by ADF was smaller than that measured by CCD and PWD, indicating less blooming. The difference in diameter was statistically significant (p < 0.05). Conclusion: ADF is a superior color Doppler technique for the assessment of blooming in venous flow during pregnancy, as it results in less blooming compared to CCD and PWD. This finding has important implications for the accurate assessment of small or slow-flow blood vessels during pregnancy.

Clinical Significance of Twinkling Artifact in the Diagnosis of Urinary Stones

The twinkling artifact is a color Doppler artifact, but it could be used in the confirmation of urinary stones. Conventionally, gray-scale criteria (echogenic foci with acoustic shadowing) is used in the diagnosis of urinary stones, but unfortunately, its reliability is very low. If the color Doppler twinkling artifact is applied in conjunction with other provocative measures, then its overall reliability exceeds 95%. To determine the clinical significance of twinkling artifact in the diagnosis of urinary stones, this cross-sectional observational study was conducted at Gilani Ultrasound Center, Lahore, Pakistan. For the determination of clinical significance, 1350 patients were recruited for this study. All the patients had renal stones of variable size and location. All the patients were evaluated with gray-scale sonographic criteria, and then color Doppler was applied to look for the twinkling artifact. The findings were confirmed with other imaging modalities (i.e., plain X-ray, computed tomography scan, etc., or during patient follow up). Sensitivity and specificity of the gray-scale ultrasound criteria in the detection of urinary stones was 96.1% and 57.9%, respectively, while the sensitivity and specificity of the color Doppler twinkling artifact in the detection of urinary stones was 100.0% and 97.4%, respectively. It was concluded that the application of twinkling artifact is useful in the confirmation of urinary stones, but specifically, it is of great diagnostic value in the small (less than 5 mm) renal stones and stones adjacent to a strong reflector (i.e., ureteric stones or stones in the prostatic urethra).

Recognizing and Minimizing Artifacts at CT, MRI, US, and Molecular Imaging.

Understanding the physical principles and technical assumptions that underlie image production can help radiologists eliminate or minimize common imaging artifacts and improve diagnostic accuracy.

Color Doppler Artifact Masking Iatrogenic Aortic Valve Injury Related to an Impella Device

The Impella (Abiomed, Danvers, MA) is a minimally invasive transvalvular left ventricular assist device (LVAD) that effectively unloads the left ventricle (LV), especially in patients with ventricular arrhythmias in the setting of a venous-arterial extracorporeal membrane oxygenator (VA ECMO).1,2 Utilization of the Impella device has increased significantly in the last few years for high-risk percutaneous coronary intervention and cardiogenic shock because of its relatively easy implantation in the catheterization lab and the operating room. Although rare, iatrogenic injury of the aortic valve (AV) can be caused by placement of the device across the AV.3 This can lead to aortic regurgitation (AR) with significant clinical consequences in the setting of cardiogenic shock. This AR can be challenging to diagnose echocardiographically because of the artifacts generated by the device when using color-flow Doppler. In this E-challenge, the authors emphasize the importance of recognizing these findings for accurate interpretation of the echocardiogram in the management of cardiogenic shock refractory to the Impella LVAD and the utility of transesophageal echocardiography (TEE).

Application of color Doppler ultrasound combined with Doppler imaging artifacts in the diagnosis and estimate of congenital hypertrophic pyloric stenosis

Congenital Hypertrophic Pyloric Stenosis (CHPS) is a disease condition that is caused as a result of pylorus wall hypertrophy and hyperplasia. In this study, we used color Doppler flow imaging (CDFI) and Doppler artifacts technique to observe the blood flow of hypertrophic pylorus tissue and the dynamic imaging of liquid passing through the pyloric canal in CHPS infants. 65 cases of CHPS infants and 50 infants without CHPS served as control group. We found that there were statistically significant differences between the blood flow grade of muscular layer and mucosal layer between CHPS and control infants, but no significant differences were observed in the same group. Doppler artifacts technique demonstrated the whole process of contrast agent flow through pyloric canal was directly observed in 35 of 65 subjects, and the internal diameter of the pyloric canal was 1.93 ± 0.33mm.Conclusion that CDFI combined with color Doppler artifacts technique was proved to be effective to observe the distribution feature and blood flow grade in each layer of pyloric canal in CHPS patients. This method provides the evidence for judging the degree of pyloric stenosis clinically, and furnishes the basis of therapy along with its clinical significance and good application value.

Microcalcifications in the breast detected by a color Doppler method using twinkling artifacts: some important discussions based on clinical cases and experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US).

The twinkling artifact is well known as a color Doppler artifact but it is still an unresolved phenomenon [Rahmouni et al., Radiology 1996;199:269-271 ; Atan et al., Astas Urol Esp 2001;35:396-402; Kamaya et al., AJR 2003;80:215-222]. Many factors affect the appearance of the twinkling artifact, such as the surface roughness of stones creating multiple reflections and a form of intrinsic noise known as clock jitter within the Doppler circuitry of the ultrasound equipment. However, no studies have reported on the twinkling artifact of breast microcalcifications. While considering these premises, I detected microcalcifications in the breast using twinkling artifacts that could not be detected on B-mode imaging. The twinkling artifact is a well-defined but not well-understood phenomenon that may assist in the detection of calcified foci. The phenomenon of the twinkling artifact is discussed here with regard to prospectively and retrospectively studied cases including experiments with a new ultrasound modality called multidetector-ultrasonography (MD-US). MD-US using detectability of the twinkling artifact in microcalcifications of the breast may play an important role in breast screening.

Spontaneous Septum Pellucidum Fenestration Complicating Posthemorrhagic Hydrocephalus in an Extremely Low Birth Weight Infant

A 25 weeks' gestation infant developed posthemorrhagic hydrocephalus. On postnatal Day 29 an ultrasound of the brain showed a fenestration between the septum pellucidum and the left lateral ventricle which continued to enlarge as the clinical course deteriorated. Color Doppler showed low flow between the septum pellucidum leaflets suggesting a persistence of erythrocytes. However, color Doppler artifacts could have resulted in this interpretation. The infant died on day 34 from multiple organ failure. Despite spontaneous fenestration of the septum pellucidum being previously described, it has not been associated with hemorrhagic hydrocephalus. Serial scanning of intracranial structures by high frequency probes can allow better understanding of the pathophysiology of neurologic complications in preterm infants.

Transthoracic Echocardiography of the HeartWare Left Ventricular Assist Device

BackgroundThe unique findings on transthoracic echocardiography of the HeartWare left ventricular assist device (LVAD) have not been previously described. Methods and ResultsHeartWare LVADs were implanted in 19 patients from May 2009 through December 2010; 152 comprehensive transthoracic echocardiograms (TTEs) performed postoperatively on these patients were retrospectively analyzed for device component visualization, inlet cannula/outflow conduit flow velocities, and imaging artifacts. The inlet cannula was adequately visualized in 66% of studies, incompletely visualized in 14%, and not visualized in 20%. Spectral Doppler interrogation of inlet cannula flow velocity was always uninterpretable due to artifact. Standard parasternal long-axis and apical views always included the inlet cannula in the imaging sector, resulting in a prominent “waterfall” color Doppler artifact obscuring the mitral valve. Inclusion of the inlet cannula in the imaging sector also precluded spectral Doppler interrogation of the mitral valve owing to artifact. The outflow conduit was partially visualized and interrogated by spectral Doppler in 68% of studies, and the average measured peak flow velocity was 1.4 m/s (range 1.0–1.9 m/s). ConclusionsThe HeartWare LVAD inlet cannula and outflow conduit are both readily visualized by TTE in a majority of patients. However, significant color and spectral Doppler artifacts occur when the inlet cannula is visualized in the imaging sector, necessitating routine off-axis Doppler interrogation of the mitral valve.

Flow turbulence or twinkling artifact? A primary observation on the intrarenal color Doppler sonography

Objective The objective of this report was to describe and potentially explain differences of intrarenal color Doppler sonography (CDUS) manifestations between blood flow turbulence and twinkling artifact. Methods We retrospectively reviewed 32 cases with appearance of focally increased color Doppler signal on intrarenal CDUS from May 1, 2007, to February 28, 2009. Indications for intrarenal CDUS in 32 cases were suspicion of renovascular hypertension, investigation of complications related to renal biopsy, or hematuria. Characteristics of the color Doppler signal, relationship between color Doppler signal and renal vessels, and the spectral Doppler sampled at the anatomic site of the focal color signal were analyzed. The value and pitfall of color Doppler in the diagnosis of the intrarenal vascular abnormality and detection of renal calculus are discussed. Results Thirty-two cases with focally increased color Doppler during sonography of native or transplanted kidneys were classified into two groups: (1) turbulent blood flow—intrarenal vascular abnormalities including intrarenal arteriovenous fistula (15 cases) and intrarenal artery stenosis (eight cases); and (2) color Doppler artifact—twinkling produced by renal calculus (nine cases). There were differences in the characteristics of the color Doppler signal, the relationship between the color signal and renal vessel, and the spectral waveform on CDUS between flow turbulence and twinkling. Conclusion Flow turbulence and twinkling artifact on intrarenal CDUS are distinguishable by analyzing the manifestations on intrarenal CDUS. Proper color Doppler setting and spectral Doppler play important roles in differentiation between flow turbulence in renal vascular abnormalities and twinkling produced by renal stones.

Color Doppler twinkling artifact in fetuses with echogenic intracardiac foci: echocardiographic observation and clinical significance

To evaluate echocardiographic characteristics and clinical relevance of color Doppler twinkling artifacts in fetuses with isolated echogenic intracardiac foci (EIF). This study included 50 fetuses with EIF, at 18-38 weeks of gestation. Echocardiographic examination, which was performed using a 1.0-5.0-MHz phased array probe, included gray-scale, color and spectral Doppler imaging. Twinkling artifacts were assessed using fetal color Doppler echocardiography on isolated EIF situated in the left and/or right ventricles. The prevalence, appearance and clinical relevance of the color Doppler twinkling artifacts were analyzed. Eight of 50 fetuses with EIF (16%) showed color Doppler twinkling artifacts, which appeared as a rapidly changing color complex seen persistently behind the EIF. The spectra obtained in all eight with color Doppler artifacts were composed of straight vertical bands occurring in mid to late systole and early diastole. After birth, none of 50 fetuses with EIF had structural heart diseases or showed clinical signs of cardiac failure. Color Doppler twinkling artifacts from isolated EIF occur in some fetuses and may be considered as an additional echocardiographic feature of EIF. Attention should be paid to the identification and interpretation of these artifacts so that they may be accurately distinguished from true color flow generated by atrioventricular valvular regurgitation jets.

Moderne Ultraschalltechniken und ihre Anwendungen am kindlichen Harntrakt

In children ultrasound plays a central role in the diagnostic imaging of the urinary tract. It is used most frequently and as a primary diagnostic option. Consequently, innovations in ultrasound technology and ultrasound contrast media have major impact on pediatric urosonography. Harmonic imaging is a modality that produces artifact-free images with high resolution. It has been shown that harmonic imaging is superior to fundamental mode in many urosonographic indications. Color Doppler is an established imaging modality, but its application for diagnosis of stones in the urinary tract, especially in children, is relatively new. The so-called twinkling sign, a color Doppler artifact at the site where one normally expects the acoustic shadow to be, enhances the conspicuity of the stone. A further development is three-dimensional (3D) ultrasound. It offers better volume measurement of the bladder and kidneys than 2D ultrasound. Contrast-enhanced voiding urosonography has already proven to be a valuable alternative in the diagnosis of vesicoureteral reflux. Thus, a significant decrease of radiation exposure has become possible as it replaces the radiological methods. With the introduction of contrast-specific ultrasound imaging modalities, further improvements in voiding urosonography are emerging.

Atypical Color Doppler Findings Related to Remote Lower-Extremity Traumatic Injury

Introduction Ultrasound artifacts can be misleading. This case demonstrates an unusual color Doppler artifact encountered while performing a lower-extremity venous evaluation. This color Doppler artifact was so unique that initially it was thought to be an incidental vascular finding. Case Study A 46-yr-old military veteran was seen in our noninvasive vascular laboratory for a lower-extremity venous evaluation because of left lower-extremity edema. He gave a history of chronic left lower-extremity pain from a war injury to his anterior left calf. An abscess developed 1.5 yr ago after he received whirlpool therapy. When the transducer was placed on the injury site, a large portion of the abscess filled with mosaic color that appeared to originate from the anterior portion. This color occurred without transducer movement. The appearance was similar to an arteriovenous fistula, which was suspected because of varicosities in the vicinity. However, pulsed Doppler revealed artifactual noise. Conclusion It was suspected that this was an impressive, atypical color Doppler reverberation artifact. The patient's tibiofibula radiographs showed pieces of shrapnel throughout the abscess. We hypothesize that the artifact was created by acceleration of the sound waves through the fluid in the large abscess with resonation between fragments of shrapnel. This is an example of a color Doppler artifact making it appear that there is flow in a location where there is none.

Color and power Doppler twinkling artifacts from urinary stones: clinical observations and phantom studies.

The purpose of this study was to determine whether color and power Doppler twinkling artifacts could be considered an additional diagnostic sonographic feature of urinary stones. A prospective study was performed in 32 patients with 20 renal stones and 16 ureteral stones to assess how often urinary stones show twinkling artifacts on Doppler sonography. Gray-scale images and color, power, and spectral Doppler images were obtained in all patients. All sonographic examinations were performed with a 3.5- or 5-MHz curvilinear phased array probe. The images were then analyzed for the presence, appearance, and intensity of the artifacts. Phantom experiments were performed with various kinds of urinary stones with high-megahertz linear phased array probes. The effects on the artifacts of the composition of the stones, of the Doppler velocity scale, and of the focal zone were investigated. Thirty (83%) of 36 urinary stones showed color and power Doppler twinkling artifacts, which appeared as a rapidly changing color complex seen persistently behind stones like a comet's tail. Twenty-two of 30 stones with the twinkling artifacts showed strong intensity artifacts. Spectra with saturated amplitude were obtained from all 30 stones showing color Doppler artifacts. In phantom experiments, the artifacts originated from all stones. The velocity range did not affect the artifacts, whereas focal zone did. Color Doppler twinkling artifacts from urinary stones occur frequently and may be considered an additional sonographic feature of urinary stones. The observation of these artifacts may be helpful in determining the presence of urinary stones.

Spectral and color Doppler artifacts.

Artifacts in spectral and color Doppler imaging can be confusing and lead to misinterpretation of flow information. The authors review these artifacts by considering three main causes: inappropriate equipment settings, anatomic factors, and physical and technical limitations of the modality. Incorrect gain, wall-filter, or velocity scale settings can cause loss of clinically important information or distortion of the tracing. Reflection of the Doppler signal from highly reflective surfaces can create a color Doppler mirror image. Vascular motion can introduce artifactual variation in velocity as the sample volume passes through different velocities in a laminar flow state. Unintentional motion can cause a generalized Doppler shift. Increasing the angle of Doppler interrogation degrades the quality of the tracing and gives the impression of spectral broadening. As angulation approaches 90 degrees, directional ambiguity can occur, suggesting bidirectional flow. Grating and side lobes can interrogate areas unrelated to the sample volume and introduce extraneous Doppler information to the apparent area of interrogation. Recognition of these artifacts is essential to proper interpretation of Doppler information and rendering a correct diagnosis.

Color Doppler Artifact in Anechoic Regions

Color Doppler Artifact in Anechoic Regions

Color Doppler artifact in anechoic regions.

For color Doppler imaging, several types of signal processing are employed in order to produce acceptable images of blood flow in blood vessels while suppressing color in moving solid tissue. The processing can produce an artifact in which color may arise from noise or from tissue motion and fill anechoic regions preferentially. This artifact may complicate the differentiation of areas with blood flow from anechoic regions without flow. By using four different color Doppler ultrasound units to image a tissue-equivalent phantom containing anechoic cylinders, artifactual color resulted when gain was raised sufficiently. This color was concentrated in anechoic regions of a gray-scale image that did not contain flow. In two instruments, this artifact was only observed when the transducer was vibrated, simulating tissue motion. In these instruments, the identification of low-frequency, high-amplitude Doppler signals is used to locate moving solid tissue and so suppress color in these regions. In the other two instruments, the presence of echoes within the image suppressed the assignment of color. With both types of processing, color may appear artifactually in echo-free regions without flow, such as fluid collections. Presence or absence of flow should be confirmed by Doppler spectral analysis. An understanding of the origin and appearance of artifactual color can prevent its occurrence from detracting from the usefulness of color Doppler imaging.

Normal Radiographic Anatomy of the Paranasal Sinuses

The twinkling artifact is a color Doppler artifact, but it could be used in the confirmation of urinary stones. Conventionally, gray-scale criteria (echogenic foci with acoustic shadowing) is used in the diagnosis of urinary stones, but unfortunately, its reliability is very low. If the color Doppler twinkling artifact is applied in conjunction with other provocative measures, then its overall reliability exceeds 95%. To determine the clinical significance of twinkling artifact in the diagnosis of urinary stones, this cross-sectional observational study was conducted at Gilani Ultrasound Center, Lahore, Pakistan. For the determination of clinical significance, 1350 patients were recruited for this study. All the patients had renal stones of variable size and location. All the patients were evaluated with gray-scale sonographic criteria, and then color Doppler was applied to look for the twinkling artifact. The findings were confirmed with other imaging modalities (i.e., plain X-ray, computed tomography scan, etc., or during patient follow up). Sensitivity and specificity of the gray-scale ultrasound criteria in the detection of urinary stones was 96.1% and 57.9%, respectively, while the sensitivity and specificity of the color Doppler twinkling artifact in the detection of urinary stones was 100.0% and 97.4%, respectively. It was concluded that the application of twinkling artifact is useful in the confirmation of urinary stones, but specifically, it is of great diagnostic value in the small (less than 5 mm) renal stones and stones adjacent to a strong reflector (i.e., ureteric stones or stones in the prostatic urethra).