Contrast-enhanced ultrasound for needle biopsy of central lung cancer with atelectasis

The Value of Contrast-Enhanced Ultrasound (CEUS) in the Evaluation of Central Lung Cancer with Obstructive Atelectasis

Purpose: To assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) alongside contrast-enhanced computed tomography (CECT) in evaluating central lung cancer (CLC). Materials and Methods: From 2006 to 2022, 54 patients with CLC and obstructive atelectasis (OAT) underwent standardized examinations using CEUS in addition to CECT. The ability to differentiate CLC from atelectatic tissue in CECT and CEUS was categorized as distinguishable or indistinguishable. In CEUS, in distinguishable cases, the order of enhancement (time to enhancement) (OE; categorized as either an early pulmonary arterial [PA] pattern or a delayed bronchial arterial [BA] pattern of enhancement), the extent of enhancement (EE; marked or reduced), the homogeneity of enhancement (HE; homogeneous or inhomogeneous), and the decrease in enhancement (DE; rapid washout [<120 s] or late washout [≥120 s]) were evaluated. Results: The additional use of CEUS improved the diagnostic capability of CECT from 75.9% to 92.6% in differentiating a CLC from atelectatic tissue. The majority of CLC cases exhibited a BA pattern of enhancement (89.6%), an isoechoic reduced enhancement (91.7%), and a homogeneous enhancement (91.7%). Rapid DE was observed in 79.2% of cases. Conclusions: In cases of suspected CLC with obstructive atelectasis, the application of CEUS can be helpful in differentiating tumor from atelectatic tissue and in evaluating CLC.

Utility of high-frequency B-mode and contrast-enhanced ultrasound for the differential diagnosis of benign and malignant pleural diseases: a prospective study

BACKGROUND

Pleural disease is a prevalent condition. As precision therapy advances, noninvasive imaging modalities play even more important roles in the evaluation of pleural diseases. This study investigated the diagnostic capabilities of high-frequency B-mode ultrasound (US) and contrast-enhanced US (CEUS) in terms of differentiating between benign and malignant pleural diseases.

METHODS

Patients with unexplained thickened pleurae were prospectively analyzed via transthoracic US. High-frequency B-mode US was used to derive the pleural thickness, morphology, and echogenicity. We analyzed the high-frequency CEUS data including the enhancement mode and time intensity curve (TIC). The cause of pleural thickening was confirmed by pleural biopsy and follow-up after the biopsy. We analyzed the differences in various ultrasonic features between the malignant and benign groups. Moreover, we plotted receiver operator curves (ROCs) and obtained the area under the curves, sensitivities, and specificities of all significant continuous variables. Multivariate logistic regression was used to assess the combined usefulness of multiple US indicators in terms of predicting malignant pleurae.

RESULTS

Thirty malignant and twenty benign thickened pleurae were finally diagnosed via pleural biopsy and at least six months of follow-up. The pleural morphology and enhancement modes significantly differed between the two groups (all P<0.05). The thickness derived from B-mode US and CEUS were significantly thicker in the malignant group (both P<0.05). Arrival time (AT) and the time to peak (TTP) of TIC were significantly shorter in the malignant group, whereas peak intensity and the area under the TIC were significantly higher in the malignant group (all P<0.05). The area under the ROC for pleural thickness derived from B-mode US was 0.819; pleural thickness derived from CEUS was 0.848; AT was 0.804; TTP was 0.750; peak intensity was 0.745; the area under the TIC was 0.743; and the combined various B-mode and CEUS parameter was 0.975.

CONCLUSIONS

Pleural thickness, morphology, enhancement mode, and the TIC of high-frequency US aided the differentiation of benign from malignant pleural diseases. Combined analysis of US indicators further improved the diagnostic capability.

Contrast enhancement for ultrasound-guided interventions: when to use it and what to expect?

The use of contrast-enhanced ultrasonography (CEUS) has recently become synonymous with high-standard ultrasonography (US). From expanding the reach of US diagnostics to improving the precision of various invasive procedures, CEUS is rapidly becoming a standard in numerous niches. However, proficiency in CEUS comes with a cost, both from a learning curve and material standpoint, and as every growing field, lacks firm evidence and standardization. Therefore, in the current paper, we aim to provide an evidence-based review of available methods and to discuss the advantages and pitfalls of CEUS in interventional procedures, trying to provide strong evidence whenever available, or at least an educated expert opinion if data are lacking.

Comparison of the Detection Rates of Different Diagnostic Methods for Primary Peripheral Lung Cancer

Objective

The present study aims to compare the detection rates of different diagnostic methods for primary peripheral lung cancer (PPLC).

Methods

The detection rate and patient information were collected from a total of 359 cases of PPLC or a suspected diagnosis of lung cancer; among these, 186 cases were simultaneously treated with fibreoptic bronchoscopy, brush inspection and flush inspection, and 173 cases underwent a computed tomography (CT)-guided percutaneous lung biopsy (PNB). The positive detection rates of the different methods were compared.

Results

In the detection of peripheral lesions (diameter of <5 cm), the CT-PNB had the significantly highest detection rate, followed by the combined basic method (fibreoptic bronchoscopy + brushing + flushing). The independent use of the three basic sampling methods showed a significantly lower detection rate compared with the combined use.

Conclusion

In the diagnosis of peripheral lung cancer, the CT-PNB had the best detection rate; hence, it could be used in clinical practice for the diagnosis of such lesions.

Clinical Applications of Contrast-Enhanced Thoracic Ultrasound (CETUS) Compared to Standard Reference Tests: A Systematic Review

INTRODUCTION

 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 to 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 a primary focus on CETUS of thoracic disorders compared to a standard reference test were included. The QUADAS-2 tool was used for quality assessment of the studies.

RESULTS

 The search identified 43 articles: 1 randomized controlled study, 6 non-randomized controlled studies, 16 non-randomized non-controlled studies, 5 case series, 10 single case reports, and 5 animal studies. The overall risk of bias was judged to be high. Diagnostic accuracy measurements of noninvasive applications of CETUS were only reported in a 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 CETUS guidance but were too heterogeneous for meta-analysis.

CONCLUSION

 The current literature on CETUS is overall heterogeneous with a few high evidence level studies, small study populations and a 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 points.

Differentiating Central Lung Tumors from Atelectasis with Contrast-Enhanced CT-Based Radiomics Features

Objectives

To evaluate the utility of radiomics features in differentiating central lung cancers and atelectasis on contrast-enhanced computed tomography (CT) images. This study is retrospective.

Materials and Methods

In this study, 36 patients with central pulmonary cancer and atelectasis between July 2013 and June 2018 were identified. A total of 1,653 2D and 2,327 3D radiomics features were extracted from segmented lung cancers and atelectasis on contrast-enhanced CT. The refined features were investigated for usefulness in classifying lung cancer and atelectasis according to the information gain, and 10 models were trained based on these features. The classification model is trained and tested at the region level and pixel level, respectively.

Results

Among all the extracted features, 334 2D features and 1,507 3D features had an information gain (IG) greater than 0.1. The highest accuracy (AC) of the region classifiers was 0.9375. The best Dice score, Hausdorff distance, and voxel AC were 0.2076, 45.28, and 0.8675, respectively.

Conclusions

Radiomics features derived from contrast-enhanced CT images can differentiate lung cancers and atelectasis at the regional and voxel levels.

The Application of Contrast Enhanced Ultrasound for Core Needle Biopsy of Subpleural Pulmonary Lesions: Retrospective Analysis in 92 Patients

The purpose of this study was to investigate the role of contrast-enhanced ultrasound (CEUS) in determining the viable target area in patients with subpleural pulmonary lesions before ultrasound-guided transthoracic core biopsy. In this retrospective study, we analyzed 92 patients with subpleural pulmonary lesions (63 males and 29 females; mean age: 65.17 ± 11.72 y). All patients underwent B-mode ultrasound, color Doppler and CEUS. Color Doppler was performed to identify the major vessels. The time to enhancement of the contrast agents, homogeneity of enhancement and the presence of areas without enhancement were recorded after administration of the contrast agents. The viable target areas were defined as regions showing enhancement relative to those without enhancement and regions showing delayed enhancement in reference to peripheral lung tissues showing early enhancement. Afterward, real-time ultrasound-guided transthoracic core needle (18 gauge) biopsies were performed and the complication rate, success rate and diagnostic accuracy were calculated. With CEUS, the needle pathways of these lesions were readjusted the biopsy strategy in 40/92 patients (43.5%). It was determined that the satisfactory rate of the subsequent biopsy specimen was 100%. The histologic diagnostic accuracy of the biopsy was 97.83%. No serious complications occurred during the biopsy. In conclusion, the application of CEUS before biopsy was able to depict the viable target areas of the lesion to readjust the biopsy routes. With the help of CEUS, ultrasound-guided core biopsy could obtain adequate samples, improve the diagnostic accuracy and reduce the complication rates of biopsies.

Contrast-enhanced ultrasound of pediatric lungs

In addition to radiography, ultrasound (US) has long proved to be a valuable imaging modality to evaluate the pediatric lung and pleural cavity. Its many inherent advantages, including real-time performance, high spatial resolution, lack of ionizing radiation and lack of need for sedation make it preferable over other imaging modalities such as CT. Since the introduction of ultrasound contrast agents (UCAs), contrast-enhanced ultrasound (CEUS) has become a valuable complementary US technique, with many well-established uses in adults and evolving uses in children. Lung CEUS applications are still not licensed and are performed off-label, although the added value of CEUS in certain clinical scenarios is increasingly reported. The limited evidence of CEUS in the evaluation of pediatric lungs focuses primarily on community-acquired pneumonia and its complications. In this clinical setting, CEUS is used to confidently and accurately diagnose necrotizing pneumonia and to delineate pleural effusions and empyema. In addition to intravenous use, UCAs can be administered directly into the pleural cavity through chest catheters to improve visualization of loculations within a complex pleural effusion, which might necessitate fibrinolytic therapy. The purpose of this paper is to present the current experience on pediatric lung CEUS and to suggest potential additional uses that can be derived from adult studies.

Contrast-enhanced ultrasound for needle biopsy of thoracic lesions

Two-dimensional ultrasound (US) and color doppler flow imaging are associated with certain limitations in the preprocedural evaluation and design of the puncture path for biopsies of thoracic lesions, such as a poorly defined boundary between the tumor and the atelectatic lesions in central lung cancer with atelectasis. Contrast-enhanced ultrasound (CEUS) can be valuable in the preoperative evaluation of the biopsy site and in increasing the accuracy of the biopsy. The present study investigated the value of clinical application of CEUS in US-guided core needle biopsy (US-CNB) in improving the diagnostic accuracy in thoracic lesions. A total of 120 patients with first-stage thoracic lesions from the Affiliated Tumor Hospital of Guangxi Medical University who underwent US-CNB were recruited and randomnly assigned to a conventional US group (n=66) and a CEUS group (n=54). All patients underwent preoperative evaluation and US-guided puncture of thoracic lesions. The intergroup differences in sonographic features, biopsy duration, biopsy success rate and complications were assessed. The CEUS group had a higher rate of detection of necrotic tissue (40.7% vs. 16.7%; χ²=8.633; P=0.003) and change of initial puncture path (48.1%) compared with the US group. In central lung cancer with atelectasis, the ability to distinguish between tumor and atelectasis was higher in the CEUS group compared with the conventional US group (31.5 vs. 7.6%; χ²=11.336; P=0.001). In addition, the CEUS group had a higher puncture success (96.3 vs. 80.3%; χ²=6.946; P=0.008) and a lower complication rate (3.7% vs. 18.2%; χ²=6.041; P=0.014) compared with the US group. CEUS can identify necrotic areas and occult tumors within atelectatic lung tissue and can be used for guiding puncture biopsy of thoracic lesions to improve the diagnostic accuracy with greater comparative clinical utility than conventional US. Pre-biopsy CEUS is especially useful for patients undergoing repeated US-CNB and those with hypovascular lesions, atelectasis or necrosis.

Hemoptysis complicating ultrasound-guided transthoracic needle lung biopsy: air bronchial sign is a risk predictor

Background

Hemoptysis is the most frequently reported complication of ultrasound-guided transthoracic needle lung biopsy (US-TTLB). However, factors influencing the occurrence of hemoptysis as a result of US-TTLB remain uncertain. Therefore, the aim of this study was to evaluate the incidence of hemoptysis as a complication of US-TTLB and to identify the related risk factors.

Methods

We retrospectively analyzed all data of patients who underwent US-TTLB from February 2013 through December 2016. The incidence, severity, and treatment of hemoptysis in each case were carefully recorded. Study variables were classified into patient-related factors (age, sex, smoking history, pulse oxygen saturation, laboratory tests and emphysema), biopsy-related factors (use of contrast agent, number of punctures and operators), and lesion-related factors (lesion location, size, pathology, length of puncture path and the grade of air bronchial sign). Univariate and multivariate logistic regression analyses were performed to analyze the risk factors of hemoptysis. We investigated whether incidence of hemoptysis increased according to increased grade of air bronchial sign by Mantel-Haenszel test.

Results

A total of 209 patients were evaluated. Hemoptysis occurred in 20 of the 209 patients (9.6%). In univariate analysis, the lesion pathology (P=0.037) and grade of air bronchial sign (P<0.001) were statistically significant factors between the hemoptysis group and the non-hemoptysis group. In multivariate analysis, the presence of multi-air bronchogram in sonographic image (odds ratio =8.946; 95% confidence interval: 2.873–27.863; P<0.001) was a statistically significant predictive risk factor for hemoptysis complicating US-TTLB. There was a significant tendency for incidence of hemoptysis with the grade of air bronchial sign (P<0.001).

Conclusions

We found that the rate of hemoptysis complicating US-TTLB was 9.6% and the severity of hemoptysis was not serious. Target lesion without air bronchogram is a safety sign, minor bronchogram means relatively low-risk, while multiple bronchogram is a highly dangerous ultrasound sign of hemoptysis.

Ultrasound-Guided Biopsy of Pleural-Based Pulmonary Lesions by Injection of Contrast-Enhancing Drugs

In this study, a total of 58 patients with single subpleural pulmonary lesions (males: 36, females: 22, mean age: 63 ± 16.2 years) who underwent contrast-enhanced ultrasonography (CEUS) and had a definite diagnosis (benign lesions:25, malignant lesions:33) were enrolled. The number of biopsies, diagnostic accuracy rate, and the incidence of complications were recorded. The nodules were divided into two size subgroups: ≥5 cm (group 1), and <5 cm (group 2). The display rate of internal necrosis and change of pre-scheduled puncture paths were compared between subgroups. Also, the arrival times, intensity and uniformity of enhancement after the contrast agent injection, as well as the display rate of internal necrosis were recorded and compared between malignant and benign lesions. Finally, the average number of punctures was 2.9 ± 0.7 times. The total diagnosis rate was 98.3%. Local pneumothorax occurred in 2 patients. Hemoptysis occurred in 1 patient. No serious complications occurred. Internal necrosis was demonstrated in 20 of 58 lesions (34.5%). Sixteen of them had changed the planned puncture path due to the large necrosis area (80%, 16/20). For lesions in group 1, necrosis was found in 15 lesions and there was a statistically significant difference in the necrosis rate between the two subgroups (15/26 vs 5/32, p = 0.001). The change in the pre-scheduled puncture path occurred in 12 patients in group 1 while 4 patients in group 2 exhibited a change in the planned puncture path (p = 0.004). There was a statistically significant difference in the arrival times and intensity of enhancement between benign and malignant lesions (p < 0.05). In conclusion, CEUS guided biopsy is an effective, sensitive, and safe method for the diagnosis of pleural-based pulmonary lesions by facilitating a distinction between necrosis and active tissue. The current findings indicated that CEUS before a biopsy may be especially vital in lesions ≥5 cm.