Figure - available from: Abdominal Radiology
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Contrast-mode image of right hepatic lobe shows a classic mirror image artifact. Note the rim-enhancing lesion seen in the far field of the liver (solid arrows) is also seen on the other side of the diaphragm (dotted arrows) as a mirror image
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Although contrast-enhanced ultrasound (CEUS) has become a widely utilized and accepted modality in much of the world, the associated contrast agents have only recently received approval in the United States. As with all radiological techniques, image artifacts are encountered in CEUS, some of which relate to commonly encountered ultrasound artifact...
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Purpose
Contrast-enhanced ultrasound (CEUS) is a new technique used to distinguish benign from metastatic superficial lymph nodes (LNs) with variable accuracy. The objective of this meta-analysis was to evaluate the accuracy of CEUS for the diagnosis of superficial metastatic LNs.
Methods
A comprehensive literature search of PubMed, Web of Science...
Background and objectives: Patients diagnosed with incidentally found adrenal tumors (incidentaloma) that do not meet the criteria for surgical treatment require follow-ups with repeated imaging. The aim of this study is to compare the accuracy of the measurements of the adrenal tumor size in ultrasound (US) with and without contrast in comparison...
Citations
... These structures exhibit inherent echogenicity before contrast agent injection that persists after application of the destruction─replenishment technique. In comparison, truly enhancing structures show increasing echogenicity after contrast agent injection and undergo immediate signal loss upon that technique's implementation (44). ...
Contrast-enhanced ultrasound (CEUS) is distinguished from CT and MRI by the use of microbubble ultrasound contrast agents (UCAs) with intravascular blood pool distribution. When performing CEUS, low-intensity ultrasound allows real-time tissue subtraction imaging, whereas high-intensity ultrasound leads to microbubble destruction, enabling visualization of the contrast inflow pattern. CEUS has exceptional contrast resolution that enables the detection of even minimal blood flow, achieving very high NPV for ruling out vascular perfusion and providing high frame rates in the evaluation of tissue perfusion dynamics. UCAs undergo hepatic metabolism and pulmonary clearance, ensuring safety in patients with renal impairment. CEUS excels in distinguishing solid from cystic renal masses, with higher sensitivity than CT or MRI for detection of lesion enhancement. CEUS can aid the further characterization of both solid and cystic lesions and may have particular applications in the surveillance of cystic masses and surveillance after renal cell carcinoma ablation. This review describes the use of CEUS to help characterize indeterminate renal masses, based on the authors' institutional experience. The article highlights key differences between CEUS and CT or MRI, and provides practical insights for performing and interpreting CEUS of renal masses.
... Physicians performing CEUS need to familiarize themselves with the technique's principles (Table 1). This will enable them to precisely interpret findings and promptly identify any artifacts [80]. Post-processing analysis with quantification CEUS utilizes an ultrasonographic contrast agent, an ultrasound machine for the emission of ultrasound beam sequences interacting with tissue, and the software necessary for image post-processing and analysis. ...
... Apart from plaque surface irregularities, CEUS may be of benefit to the detection of the intraluminal thrombus [105]. When assessing CEUS images, it is crucial to differentiate the hyperechogenic parts of plaques (calcifications) resembling contrast enchantment by cross-checking with low-MI grayscale images [80]. ...
The risk assessment for carotid atherosclerotic lesions involves not only determining the degree of stenosis but also plaque morphology and its composition. Recently, carotid contrast-enhanced ultrasound (CEUS) has gained importance for evaluating vulnerable plaques. This review explores CEUS’s utility in detecting carotid plaque surface irregularities and ulcerations as well as intraplaque neovascularization and its alignment with histology. Initial indications suggest that CEUS might have the potential to anticipate cerebrovascular incidents. Nevertheless, there is a need for extensive, multicenter prospective studies that explore the relationships between CEUS observations and patient clinical outcomes in cases of carotid atherosclerotic disease.
... These doses are likely to suffice for the majority of applications; however, the dose might need to be optimized based on the US unit/UCA combination depending on the sensitivity of the software, exam indication (highly vascular target versus deeply located lesion), transducer frequency, and contrast administration equipment [14,18,29,30]. An advantage of CEUS over other contrastenhanced imaging techniques is that the contrast bolus can be repeated if an area needs to be interrogated again for further assessment of findings from the first injection or if additional lesions need to be evaluated. ...
... A phenomenon of "pseudo-washout" has been described in lesions with slow blood flow where the continuous insonation of the microbubbles traversing these lesions results in microbubble destruction [29]. Microbubble destruction can be mistaken for lesion washout. ...
Intravenous contrast-enhanced ultrasound (CEUS) can serve as a diagnostic or problem-solving tool in pediatric imaging. CEUS of abdominal solid organs has been reported for a number of indications. The approach to the examination broadly falls into two categories: evaluation of a focal lesion or surveillance of an organ or organs for lesions or perfusion abnormalities. A consistent, technical imaging protocol for both of these clinical scenarios facilitates integration of routine use of CEUS in an imaging department. Here we review the CEUS imaging protocols for abdominal organs in children, including technical and solid-organ-specific considerations.
... This predisposes them to rupture even with contrast-specific settings. Unintentional rupture of microbubbles can cause a pseudowashout effect, in which contrast signal appears falsely reduced because of the destruction of microbubbles and not from actual dissipation, potentially leading to interpretation errors [19]. ...
... The focal zone is the point of maximal acoustic pressure and therefore maximal resolution in the area of insonation [12,19,22]. When scanning a particular structure in B-mode US, the focal zone should be placed at the level of interest. ...
... To improve visualization, the center frequency of the probe should be adjusted to balance between resolution and penetration. A lower imaging frequency might enable the signal to penetrate more deeply; however, the trade-off is lower spatial resolution, which could result in suboptimal imaging of smaller vessels [12,19,22]. Increasing the MI can improve signal penetration at greater depths, and this practice is commonly used in B-mode US. ...
When performing contrast-enhanced ultrasound (CEUS), ultrasound (US) scanner settings, examination technique, and contrast agent dose and administration must be optimized to ensure that high-quality, diagnostic and reproducible images are acquired for qualitative and quantitative interpretations. When carrying out CEUS in children, examination settings should be tailored to their body size and specific indications, similar to B-mode US. This review article details the basic background knowledge that is needed to perform CEUS optimally in children, including considerations related to US scanner settings and US contrast agent dose selection and administration techniques.
... High doses of microbubbles cause shadowing similar to ribs, due to the attenuation of beam. This can be observed in intracavitary applications of CEUS, where the solution to be administered needs to be carefully reconstituted, including only a drop (0.1 ml) of microbubbles [70,71]. ...
Ultrasound (US) is an ideal diagnostic tool for paediatric patients owning to its high spatial and temporal resolution, realtime imaging, and lack of ionizing radiation and bedside availability. The lack of superficial adipose tissue and favourable acoustic windows in children makes US the first line of investigation for evaluation of pleural and chest wall abnormalities.In the first part of the topic the technical requirements were explained and the use of ultrasound in the lung and pleura in paediatric patients were discussed. In the second part lung parenchymal diseases with their subpleural consolidations are reflected. In the third part, the use of ultrasound for chest wall, mediastinum, diaphragmatic diseases, trachea, interventions and artifacts in paediatric patients are summarized.
... Furthermore, DCE-US results correlated with the results of advanced diagnostic imaging (19). The contrast agents used in DCE-US are gas-filled microbubbles stabilized in a lipoprotein shell that have a diameter of 1-3 µm, which is small enough to migrate freely through the circulation and large enough to remain in the vascular space (20)(21)(22). Capillary filling results in diffuse enhancement of perfused tissue. Most of the contrast agent is excreted through the lungs within 20 min after administration (23). ...
Electrochemotherapy (ECT) and/or gene electrotransfer of plasmid DNA encoding interleukin-12 (GET pIL-12) are effective treatments for canine cutaneous, subcutaneous, and maxillofacial tumors. Despite the clinical efficacy of the combined treatments of ECT and GET, data on parameters that might predict the outcome of the treatments are still lacking. This study aimed to investigate whether dynamic contrast-enhanced ultrasound (DCE-US) results of subcutaneous tumors differ between tumors with complete response (CR) and tumors without complete response (non-CR) in dogs treated with ECT and GET pIL-12. Eight dogs with a total of 12 tumor nodules treated with ECT and GET pIL-12 were included. DCE-US examinations were performed in all animals before and immediately after therapy as well as 8 h and 1, 3, and 7 days later. Clinical follow-up examinations were performed 7 and 14 days, 1 and 6 months, and 1 year after treatment. Numerous significant differences in DCE-US parameters were noted between tumors with CR and non-CR tumors; perfusion and perfusion heterogeneity were lower in CR tumors than in non-CR tumors. Therefore, studies with larger numbers of patients are needed to investigate whether DCE-US results can be used to predict treatment outcomes and to make effective decisions about the need for repeated therapy or different treatment combinations in individual patients.
... While advantageous in multiple clinical scenarios, a drawback of CEUS is the need for UCA administration and/or study oversight by a radiologist, precluding the radiologist from interpreting other studies during this time. Unique CEUS artifacts have been described [1]. Appropriate use of CEUS is also important. ...
... However, enhancement may be inferior using higher frequency transducers (>8-9MHz) because microbubble oscillation occurs optimally in the mid frequency range (4-8MHz) [28]. Additionally, microbubble destruction, especially in the near-field, increases if a higher frequency transducer is used [1]. To improve CEUS quality, either a lower frequency transducer may allow better visualization, or the UCA dose can be slightly increased. ...
... Thus, CEUS is an ideal complement to Color Doppler findings in assessing vascular complications, especially when the latter provides inconclusive results. Since UCAs administration can introduce several artifacts [31], Color Doppler examination should be performed prior to CEUS. Nonetheless, it has been reported that interrogation in the late post-contrast phase can enhance the Doppler signal by trading on residual microbubbles, thus improving the visibility of smaller vessels that might be missed without contrast [32]. ...
Contrast-enhanced ultrasound (CEUS) is gaining ever-increasing acceptance in the preoperative and postoperative evaluation of liver-transplanted patients. While indications are still a matter of research, CEUS is used in tertiary centers to supplement ultrasound (US) and Color Doppler US examination, with the potential of providing a comprehensive first-line ultrasound-based diagnosis. Alternatively, CEUS is used as a problem-solving tool when previous cross-sectional or US imaging was inconclusive, especially in assessing hepatocellular carcinoma, parenchymal perfusion abnormalities, the vascular status, and even the biliary tree. This review describes the potential use for CEUS in the setting of orthotopic liver transplantation (OLT).
... The technical considerations for ultrasound (US) imaging with a UCA are related to the unique properties of the UCA, and the interaction with the US beam. An understanding of these technical attributes is important to achieve a diagnostic study, and particular attention to artefacts as a consequence of the UCA/US interaction is essential [7]. The UCA can easily be destroyed by the energy of the US beam, and modern techniques using low mechanical index (MI) and non-linear imaging achieve good results [8]. ...
The technique for an intravenous contrast-enhanced ultrasound examination for an adult patient is well established, and the methodology and technique for the paediatric patient are similar but with some important differences. The essential aspects for both an intravenous examination and the intracavitary examination for contrast-enhanced voiding urosonography is parental consent and confidence of the technique, with the cooperation of the child. The important aspects for the examination include an indication for the study, the type and dose of the contrast agent, the technique for the specific contrast examination, the ultrasound machine and the software availability. The operator should have the appropriate training in the technique of ultrasound contrast examinations and should attain a level of competence in the technique. The possibility of a contrast reaction should necessitate the availability of resuscitation equipment, individual examiner resuscitation competence and access to the relevant trained expertise to manage any reaction to the contrast agent. A detailed clinical report of the findings is essential.
... Nevertheless, it must be mentioned that not only patient and lesion characteristics influence image quality, and therefore diagnostic accuracy, but also artifacts which are partially CEUS-specific, such as near-field signal loss due to microbubble destruction-which can be influenced by using a specific configuration of the US machine [13,14]. ...
Obesity and bowel gas are known to impair image quality in abdominal ultrasound (US). The present study aims at identifying individual factors in B-mode US that influence contrast-enhanced US (CEUS) image quality to optimize further imaging workup of incidentally detected focal renal masses. We retrospectively analyzed renal CEUS of focal renal masses ≤ 4 cm performed at our center in 143 patients between 2016 and 2020. Patient and lesion characteristics were tested for their influence on focal and overall image quality assessed by two experienced radiologists using Likert scales. Effects of significant variables were quantified by receiver operating characteristics (ROC) curve analysis with area under the curve (AUC), and combined effects were assessed by binary logistic regression. Shrunken kidney, kidney depth, lesion depth, lesion size, and exophytic lesion growth were found to influence focal renal lesion image quality, and all factors except lesion size also influenced overall image quality. Combination of all parameters except kidney depth best predicted good CEUS image quality showing an AUC of 0.91 (p < 0.001, 95%-CI 0.863–0.958). The B-mode US parameters investigated can identify patients expected to have good CEUS image quality and thus help select the most suitable contrast-enhanced imaging strategy for workup of renal lesions.
