Clinical applications of contrast-enhanced thoracic ultrasound (CETUS) compared to standard reference tests: a systematic review

Abstract

Contrast-enhanced ultrasound is utilized in an increasing array of medical fields, including thoracic medicine. However, the technique is still relatively new and only sporadically mentioned in current guidelines and recommendations. The aim of this systematic review is to provide a literature overview and critically appraise the current clinical applications of contrast-enhanced thoracic ultrasound (CETUS). Materials and Methods:A systematic literature search using major electronic databases and in accordance with PRISMA guidelines was performed. Studies with primary focus of CETUS of thoracic disorders compared to standard reference test were included. The QUADAS-2 tool was used for quality assessment of the studies. Results:The search identified 43 articles. One randomized controlled study, six non-randomized controlled studies, 16 non-randomized non-controlled studies, five case series, 10 single case reports, and five animal studies. The risk of bias was overall judged high. Diagnostic accuracy measurements of non-invasive applications of CETUS were only reported in few studies and they were too dissimilar for meta-analysis. Six studies compared CETUS-guided versus ultrasound-guided transthoracic needle biopsy of thoracic masses. They individually reported a significant increase in diagnostic accuracy in favor of CETUSguidance, but were too heterogeneous for meta-analysis. Conclusion:The current literature of CETUS is overall heterogeneous with few high evidence level studies, small study populations and high risk of bias. CETUS-guided biopsy is the most frequent clinical application and increases diagnostic accuracy compared to ultrasound-guidance by an average of 14.6 percentage point.

Development and Prospective Validation of an Ultrasound Prediction Model for the Differential Diagnosis of Benign and Malignant Subpleural Pulmonary Lesions: A Large Ambispective Cohort Study

“…As for CEUS, the perfusion mode, degree of enhancement, homogeneity, microvascular characteristics, and especially AT are recommended indicators ( 8 – 19 ). However, studies that proposed the above indicators also has limitations, including small sample size, inconsistent conclusions from different researchers, strong subjectivity, and no multi factor analysis ( 9 ). In this large-scale and multiparameter study, we constructed a new US prediction model for the differential diagnosis of benign and malignant SPLs and obtained good discrimination and calibration.…”

“…Quantitative CEUS parameters were measured and calculated according to the time-intensity curve (TIC). We used the TIC analysis software in LOGIQ E9 to select the earliest enhancing areas of air-filled lung tissues, the thoracic wall and the lesion as the regions of interest (ROIs) to plot TICs and obtained the following parameters: (a) AT of lung, (b) AT of thoracic wall, (c) AT of lesion, (d) lesion-lung AT difference, (e) ratio of AT difference, (f) basic intensity (BI), (g) peak intensity (PI), (h) time to peak (TTP), (i) WIR, (j) WOR ( 9 ).…”

“…Compared with CT, ultrasound (US) has the advantage of real time, non-radiation, and bedside availability, and has been used in assessing lung disease since the 19th century ( 6 ). To date, both B-mode US (B-US) and contrast-enhanced US (CEUS) have been proven to be valuable in the differential diagnosis of subpleural pulmonary lesions (SPLs) ( 7 – 9 ). Reportedly, qualitative parameters such as degree and homogeneity of enhancement, perfusion pattern, and vascular sign; and quantitative parameters such as arrival time (AT), lesion-lung AT difference, wash-in rate (WIR) and wash-out rate (WOR) were the potentially useful parameters ( 8 – 19 ).…”

“…Nevertheless, they are still limited to the exploration of small samples or single indicators, and the level of evidence is low ( 8 – 19 ). Therefore, the value of lung US requires a larger and more robust study design ( 9 ).…”

ERS International Congress 2020: highlights from the Clinical Techniques, Imaging and Endoscopy assembly

“…A systematic review of the current clinical application of contrast-enhanced thoracic ultrasound revealed that its use to guide transthoracic biopsies could increase diagnostic accuracy by 14.6% on average [ 53 ]. However, the use of contrast-enhanced ultrasound to distinguish between benign or malignant lesions is not yet well supported by evidence, as overall the studies were heterogeneous, small and with high risk of bias.…”