Contrast enhanced ultrasonography (CEUS) in peripheral lung lesions: A study of 60 cases. J Ultrasound. 2008;11:89-96. [PMID: 23397023 DOI: 10.1016/j.jus.2008.05.008]

The Value of Necrotic Area Features in Contrast-Enhanced Ultrasound for Distinguishing Between Benign and Malignant Subpleural Pulmonary Lesions

OBJECTIVE

To analyze Necrotic Area Features of subpleural pulmonary lesions (SPLs) demonstrated by contrast-enhanced ultrasound (CEUS) and investigate their value in differentiating between malignant and benign SPLs.

METHODS

Patients with SPLs who underwent CEUS at our hospital from January to May 2021. The following patient information was recorded: (i) age, (ii) sex, (iii) lesion size, (iv) lesion location, (v) size of necrotic areas and (vi) necrotic area morphology, including sieve-like necrosis, necrotic area with septal enhancement, necrotic area with annular enhancement margins, and necrotic area with burr-like enhancement margins. These parameters were analyzed using univariate and multivariate logistic regression. Subgroup analyses based on lesion size were further conducted using the collected data.

RESULTS

A total of 212 patients with 212 SPLs were enrolled, comprising 99 benign and 113 malignant cases. Significant differences were observed between malignant and benign groups in terms of age, sex, lesion size and necrotic area morphology (all, p < 0.05).

CONCLUSION

Necrotic area's features observed on CEUS were valuable for distinguishing between benign and malignant SPLs. Age, sex, lesion size and the presence of burr-like enhancement margins are identified as independent predictors of malignant lesions.

Development and validation of a nomogram for predicting histologic subtypes of subpleural non-small cell lung cancer using ultrasound parameters and clinical data

Aims

To develop and validate an individualized nomogram for differentiating the histologic subtypes (adenocarcinoma and squamous cell carcinoma) of subpleural non-small cell lung cancer (NSCLC) based on ultrasound parameters and clinical data.

Methods

This study was conducted retrospectively between March 2018 and December 2019. Patients were randomly assigned to a development cohort (DC, n=179) and a validation cohort (VC, n=77). A total of 7 clinical parameters and 16 ultrasound parameters were collected. Least absolute shrinkage and selection operator regression analysis was employed to identify the most significant predictors utilizing a 10-fold cross-validation. The multivariate logistic regression model was applied to investigate the relevant factors. An individualized nomogram was then developed. Receiver operating characteristic (ROC) curve, calibration plot and decision curve analysis (DCA) were applied for model validation in both DC and VC.

Results

Following the final regression analysis, gender, serum carcinoembryonic antigen, lesion size and perfusion defect in contrast-enhanced ultrasound were entered into the nomogram. The model showed moderate predictive ability, with an area under the ROC curve of 0.867 for DC and 0.838 for VC. The calibration curves of the model showed good agreement between actual and predicted probabilities. The ROC and DCA curves demonstrated that the nomogram exhibited a good predictive performance.

Conclusion

We developed a nomogram that can predict the histologic subtypes of subpleural NSCLC. Both internal and external validation revealed optimal discrimination and calibration, indicating that the nomogram may have clinical utility. This model has the potential to assist clinicians in making treatment recommendations.

Accuracy of Contrast-enhanced Ultrasonography with Perfluorobutane for Diagnosing Subpleural Lung Lesions

RATIONALE AND OBJECTIVES

To investigate the diagnostic value of perfluorobutane-enhanced ultrasound (US) examinations for differentiating benign from malignant subpleural lung lesions.

METHODS

This single-center, retrospective study enrolled consecutive patients with subpleural lung lesions between January 2022 and March 2023. The cause of the lung lesions was confirmed by biopsy and follow-up examinations. The lesions were continuously evaluated using perfluorobutane-enhanced US for 0-180 s, and washout (WT) was observed after 3, 5, and 10 min. Univariate and multivariate analyses were used to identify significant US features, which were evaluated for their diagnostic performance. The diagnostic performance of combining several features for predicting malignant lung lesions was also assessed by multivariate logistic regression analysis.

RESULTS

Seventy cases were included (17 benign lesions [13 men, 4 women; mean age: 57.5 ± 12.2 years] and 53 malignant lesions [41 men, 12 women; mean age: 63.3 ± 11.6 years]). Peak intensity (PI), arrival time (AT), and WT after 10 min significantly differed between malignant and benign lesions. The sensitivity and accuracy were significantly higher for 10-minute WT than for AT (both p < 0.05). The area under the curve of the combined diagnostic evaluation with AT, PI, and 10-minute WT was 0.897 (95% [CI]: 0.806-0.988), which was significantly higher than that of AT or PI alone.

CONCLUSION

Perfluorobutane-enhanced US can differentiate benign from malignant lung lesions, and combining AT, PI, and 10-minute WT for diagnostic purposes performed better than a single feature.

Perfusion Patterns of Peripheral Pulmonary Metastasis Using Contrast-Enhanced Ultrasound (CEUS) and Their Correlation with Immunohistochemically Detected Vascularization Pattern

PURPOSE

Description of the perfusion of pulmonary metastasis by contrast-enhanced ultrasound (CEUS) and their correlation with vascularization patterns represented by immunohistochemical CD34 endothelial staining.

PATIENTS AND METHODS

The data of 54 patients with histologic proven peripheral pulmonary metastasis, investigated between 2004 and 2023 by CEUS. These CEUS parameters were evaluated: time to enhancement (TE), categorized as early pulmonary-arterial (PA) or delayed bronchial-arterial (BA) patterns; extent of enhancement (EE), either marked or reduced; homogeneity of enhancement (HE), homogeneous or inhomogeneous; and decrease of enhancement (DE), rapid washout (<120 s) or late washout (≥120 s). Additionally, tissue samples in 45 cases (83.3%) were stained with CD34 antibody for immunohistochemical analysis.

RESULTS

In total, 4 lesions (7.4 %) exhibited PA enhancement, and 50 lesions (92.6%) demonstrated BA enhancement. Furthermore, 37 lesions (68.5%) showed marked enhancement, while 17 lesions (31.5%) exhibited reduced enhancement. The enhancement was homogeneous in 28 lesions (51.86%) and inhomogeneous in 26 lesions (48.14%). Additionally, 53 lesions (98.1%) displayed a rapid washout. A chaotic vascular pattern indicative of a bronchial arterial blood supply was identified in all cases (45/45, 100%), including all 4 lesions with PA enhancement.

CONCLUSION

Pulmonary metastases in CEUS predominantly reveal bronchial arterial enhancement and a rapid washout. Regarding EE and HE, pulmonary metastases show heterogeneous perfusion patterns. A PA enhancement in CEUS does not exclude BA neoangiogenesis.

Conventional and Contrast-enhanced US of the Lung: From Performance to Diagnosis

In recent years, lung US has evolved from a marginal tool to an integral component of diagnostic chest imaging. Contrast-enhanced US (CEUS) can improve routine gray-scale imaging of the lung and chest, particularly in diagnosis of peripheral lung diseases (PLDs). Although an underused tool in many centers, and despite inherent limitations in evaluation of central lung disease caused by high acoustic impedance between air and soft tissues, lung CEUS has emerged as a valuable tool in diagnosis of PLDs. Owing to the dual arterial supply to the lungs via pulmonary and bronchial (systemic) arteries, different enhancement patterns can be observed at lung CEUS, thereby enabling accurate differential diagnoses in various PLDs. Lung CEUS also assists in identifying patients who may benefit from complementary diagnostic tests, including image-guided percutaneous biopsy. Moreover, lung CEUS-guided percutaneous biopsy has shown feasibility in accessible subpleural lesions, enabling higher histopathologic performance without significantly increasing either imaging time or expenses compared with conventional US. The authors discuss the technique of and basic normal and pathologic findings at conventional lung US, followed by a more detailed discussion of lung CEUS applications, emphasizing specific aspects of pulmonary physiology, basic concepts in lung US enhancement, and the most commonly encountered enhancement patterns of different PLDs. Finally, they discuss the benefits of lung CEUS in planning and guidance of US-guided lung biopsy. ©RSNA, 2024 Supplemental material is available for this article.

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.

Lung ultrasound in a nutshell. Lines, signs, some applications, and misconceptions from a radiologist's point of view. Part 2

In recent years, lung ultrasound (LUS) has developed rapidly, and it is gaining growing popularity in various scenarios. There are constant attempts to introduce it to new fields. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemics. In the first part of this review we discuss lines, signs and pheno-mena, profiles, some applications, and misconceptions. An aim of the second part of the review is mainly to discuss some advanced applications of LUS, including lung elastography, lung spectroscopy, colour and spectral Doppler, contrast-enhanced ultrasound of lung, speckled tracking of pleura, quantification of pulmonary oedema, predicting success of talc pleurodesis, asthma exacerbations, detecting chest wall invasion by tumours, lung biopsy, estimating pleural effusion volume, and predicting mechanical ventilatory weaning outcome. For this purpose, we reviewed literature concerning LUS.

The Role of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Malignant and Benign Subpleural Lung Lesions

Background: The application of transthoracic contrast-enhanced ultrasound (CEUS) to the study of peripheral lung lesions is still a topic of debate. The main objective of this review was to evaluate the diagnostic accuracy of CEUS in the diagnosis of malignant subpleural pulmonary consolidations and, therefore, differentiate them from benign ones. Methods: Papers published before December 2023 were detected through a search of PubMed, Cochrane library, and Embase. The pooled specificity and sensitivity, summary receiver operating characteristic (SROC) curve and diagnostic odds ratio (DOR) were used. Results: CEUS is characterized by a pooled sensitivity of 0.95 (95% CI: 0.93-0.97) and a pooled specificity of 0.93 (95% CI: 0.90-0.95) in differentiating benign and malignant subpleural lung diseases; the AUC of SROC was 0.97. Homogeneous CE was characterized by a pooled sensitivity of 0.43 (95% CI: 0.40-0.45) and the pooled specificity of 0.49 (95% CI: 0.46-0.52). Non-homogeneous CE displayed a pooled sensitivity of 0.57 (95% CI: 0.55-0.60) and a pooled specificity of 0.51 (95% CI: 0.48-0.54). The lack of CE displayed a pooled sensitivity of 0.01 (95% CI: 0.00-0.06) and a pooled specificity of 0.76 (95% CI: 0.64-0.85). Marked CE displayed a pooled sensitivity of 0.41 (95% CI: 0.37-0.44) and a pooled specificity of 0.54 (95% CI: 0.50-0.58). Non-marked CE displayed a pooled sensitivity of 0.59 (95% CI: 0.56-0.63) and a pooled specificity of 0.46 (95% CI: 0.42-0.50). The early AT displayed a pooled sensitivity of 0.04 (95% CI: 0.02-0.08) and a pooled specificity of 0.83 (95% CI: 0.77-0.87). The early wash out displayed a pooled sensitivity of 0.61 (95% CI: 0.48-0.72) and a pooled specificity of 0.98 (95% CI: 0.92-1.00). The delayed wash out displayed a pooled sensitivity of 0.15 (95% CI: 0.10-0.20) and a pooled specificity of 0.69 (95% CI: 0.62-0.75). Conclusions: CEUS is characterized by excellent diagnostic accuracy for the diagnosis of the malignancy of subpleural lung lesions. By separately analyzing the CEUS findings, the diagnostic accuracy values are considerably lower and not significant in some cases. The simultaneous evaluation of multiple CEUS features allows us to reach an excellent diagnostic accuracy. Non-homogeneous CE with early wash out are the most indicative features of malignancy of a lung lesion.

Contrast-Enhanced Ultrasound of the Chest in Children and Adolescents: A Pilot Study for Assessment of Added Diagnostic Value

OBJECTIVES

To determine the added diagnostic value of contrast-enhanced ultrasound (CEUS) in pediatric chest abnormalities by comparing interpretation of CEUS studies and confidence level to conventional US studies.

METHODS

CEUS studies in patients with a variety of clinically suspected chest abnormalities performed between 2016 and 2020 were reviewed and compared to same-day conventional US studies. Examinations were independently interpreted by 4 radiologists blinded to clinical and other imaging data. Rater confidence was classified as low, moderate, or high. Diagnostic accuracy was determined by comparing image interpretation to patient outcome as the ground truth. Interobserver agreement was also assessed.

RESULTS

Sixteen patients (10 male) with 18 CEUS studies were included. Median rater agreement with ground truth was significantly higher for CEUS (100%) than conventional US (50%; P = .004). Median rater confidence was high (3.0) for CEUS, and low-moderate (1.5) for conventional US (P < .001). CEUS sensitivity (54.6-81.8%) and specificity (63.4-100.0%) were greater than conventional US (45.5-72.7% and 12.5-63.5%, respectively). CEUS false positives (0-4) and false negatives (2-5) were fewer than conventional US (4-7 and 3-6, respectively). Except for one rater pair where agreement was substantial (κ = .78, P < .01), inter-rater agreement for CEUS for all other rater pairs was nonsignificant (κ = .25-0.51, P ≥ .07). Agreement for conventional US was moderate and statistically significant for 3 rater pairs (κ = .55-0.78) and nonsignificant for the remaining 3 rater pairs (P ≥ .06).

CONCLUSIONS

CEUS adds diagnostic value to the assessment of a variety of chest abnormalities. The data support further evaluation of the role of CEUS as a non-invasive, problem-solving technique in children.

Diagnosis of benign and malignant peripheral lung lesions based on a feature model constructed by the random forest algorithm for grayscale and contrast-enhanced ultrasound

Rationale and objectives

To construct a predictive model for benign and malignant peripheral pulmonary lesions (PPLs) using a random forest algorithm based on grayscale ultrasound and ultrasound contrast, and to evaluate its diagnostic value.

Materials and methods

We selected 254 patients with PPLs detected using chest lung computed tomography between October 2021 and July 2023, including 161 malignant and 93 benign lesions. Relevant variables for judging benign and malignant PPLs were screened using logistic regression analysis. A model was constructed using the random forest algorithm, and the test set was verified. Correlations between these relevant variables and the diagnosis of benign and malignant PPLs were evaluated.

Results

Age, lesion shape, size, angle between the lesion border and chest wall, boundary clarity, edge regularity, air bronchogram, vascular signs, enhancement patterns, enhancement intensity, homogeneity of enhancement, number of non-enhancing regions, non-enhancing region type, arrival time (AT) of the lesion, lesion-lung AT difference, AT difference ratio, and time to peak were the relevant variables for judging benign and malignant PPLs. Consequently, a model and receiver operating characteristic curve were constructed with an AUC of 0.92 and an accuracy of 88.2%. The test set results showed that the model had good predictive ability. The index with the highest correlation for judging benign and malignant PPLs was the AT difference ratio. Other important factors were lesion size, patient age, and lesion morphology.

Conclusion

The random forest algorithm model constructed based on clinical data and ultrasound imaging features has clinical application value for predicting benign and malignant PPLs.

Imaging Microbubbles With Contrast-Enhanced Endobronchial Ultrasound

OBJECTIVE

Endobronchial ultrasound (EBUS) is commonly used to guide transbronchial needle biopsies for the staging of lymph nodes in non-small cell lung cancer patients. Although contrast-enhanced ultrasound (CEUS) and microbubbles (MBs) can improve the diagnostic accuracy in tumors, the ability of contrast-enhanced EBUS (CE-EBUS) to image MBs has not yet been comprehensively evaluated. In this study, we assessed the ability of a CE-EBUS system (Olympus EU-ME2 PREMIER and BF-UC180F bronchoscope) to detect laboratory-synthesized MBs in comparison to clinical (Toshiba Aplio SSA-790A) and pre-clinical (VisualSonics Vevo 2100) CEUS systems in vitro and in vivo, respectively.

METHODS

Agar flow phantoms and reference tissue were used to assess CE-EBUS MB imaging in vitro, and A549 tumor-bearing athymic nude and AE17-OVA tumor-bearing C57BL/6 mice were used to assess MB detectability and perfusion in vivo, respectively.

RESULTS

Results revealed that despite the lower sensitivity of CE-EBUS to MB concentration in comparison to clinical CEUS, CE-EBUS yielded a similar contrast-to-tissue ratio (CTR) in vitro of 28.9 ± 4.5 dB for CE-EBUS, compared with 29.7 ± 2.6 dB for clinical CEUS (p < 0.05). In vivo, CE-EBUS generated a perfusion curve highly correlated with that obtained with the pre-clinical CEUS system (Pearson correlation coefficient = 0.927, p < 0.05). Moreover, CE-EBUS yielded a CTR 2.7 times higher than that obtained with the pre-clinical ultrasound system.

CONCLUSION

These findings together suggest that CE-EBUS can perform contrast imaging comparable to that produced by commercial pre-clinical and clinical ultrasound systems, with potential for clinical characterization of mediastinal lymph nodes in lung cancer patients.

The Role of Contrast-Enhanced Ultrasound Plus Color Parametric Imaging in the Differential Diagnosis of Subpleural Pulmonary Lesions

OBJECTIVES

To distinguish benign and malignant subpleural pulmonary lesions (SPLs) with contrast-enhanced ultrasound (CEUS) and color parametric imaging (CPI), and evaluate the role of CEUS plus CPI in the differential diagnosis of pathological types of SPLs.

METHODS

One hundred and thirty-six patients underwent CEUS with a Logiq E9 XD Clear ultrasonic machine equipped with a 3.5- to 5.0-MHz C5-1 transducer in our center were enrolled in our study, including 27 cases of benign lesions and 109 cases of malignant lesions. The ultrasound contrast agent used in this study was SonoVue. CEUS images and CPI of all cases were reviewed and analyzed by the resident and staff radiologist groups separately.

RESULTS

With CEUS alone, by both the two groups, the main enhancement pattern of benign SPLs was arborization (P < .001), while centripetal enhancement pattern occurred more frequently in malignant SPLs (P < .001). With CEUS plus CPI, by both the two groups, the main enhancement pattern of benign SPLs was arborization (P < .001), while those of malignant SPLs were centripetal (P < .001) and eccentric (P < .05). The diagnosis performance of CEUS plus CPI was significantly higher than that of CEUS alone in both the resident (area under the curve [AUC] = 0.857 vs 0.677, P < .001) and staff (AUC = 0.866 vs 0.681, P < .001) groups. Moreover, CPI offered remarkable inter-consistency improvements in the enhancement pattern determination between the two groups.

CONCLUSION

The CEUS enhancement patterns would provide information of blood perfusion patterns in the differential diagnosis of benign and malignant SPLs. The diagnosis performance could be significantly improved by CEUS plus CPI compared with CEUS alone.

B-mode ultrasound and contrast-enhanced ultrasound for evaluation of pneumonia: A pictorial essay

Due to their often peripheral pleural-based location, pneumonias can be visualised by B-mode ultrasound. Therefore, sonography can be used as an alternative imaging modality to chest X-ray in suspected cases of pneumonia. Depending on the clinical background of the patient, and various underlying pathological mechanisms, a heterogeneous pattern of pneumonia is seen in both B-mode lung ultrasound and contrast-enhanced ultrasound. Here, we describe the spectrum of sonographic manifestations of pneumonic/inflammatory consolidation on B-mode lung ultrasound and contrast-enhanced ultrasound.

Contrast-Enhanced Ultrasound in Distinguishing between Malignant and Benign Peripheral Pulmonary Consolidations: The Debated Utility of the Contrast Enhancement Arrival Time

Background. Limited studies and observations conducted on a too small number of patients prevent determining the actual clinical utility of pulmonary contrast-enhanced ultrasound (CEUS). The aim of the present study was to examine the efficacy of contrast enhancement (CE) arrival time (AT) and other dynamic CEUS findings for differentiating between malignant and benign peripheral lung lesions. Methods. 317 inpatients and outpatients (215 men, 102 women; mean age: 52 years) with peripheral pulmonary lesions were included in the study and underwent pulmonary CEUS. Patients were examined in a sitting position after receiving an intravenous injection of 4.8 mL of sulfur hexafluoride microbubbles stabilized by a phospholipid shell as ultrasound contrast agent (SonoVue-Bracco; Milan, Italy). Each lesion was observed for at least 5 min in real-time and the following temporal characteristics of enhancement were detected: the arrival time (AT) of microbubbles in the target lesion; the enhancement pattern; the wash-out time (WOT) of microbubbles. Results were then compared in light of the definitive diagnosis of community acquired pneumonia (CAP) or malignancies, which was not known at the time of CEUS examination. All malignant cases were diagnosed by histological results, while pneumonia was diagnosed on the basis of clinical and radiological follow-up, laboratory findings and, in some cases, histology. Results. CE AT has not been shown to differ between benign and malignant peripheral pulmonary lesions. The overall diagnostic accuracy and sensibility of a CE AT cut-off value < 10 s in discriminating benign lesions were low (diagnostic accuracy: 47.6%; sensibility: 5.3%). Poor results were also obtained in the sub-analysis of small (mean diameter < 3 cm) and large (mean diameter > 3 cm) lesions. No differences were recorded in the type of CE pattern showed between benign and malignant peripheral pulmonary lesions. In benign lesions we observed a higher frequency of delayed CE wash-out time (WOT) > 300 s. Anyhow, a CE WOT cut-off value > 300 s showed low diagnostic accuracy (53.6%) and sensibility (16.5%) in discriminating between pneumonias and malignancies. Similar results were also obtained in the sub-analysis by lesion size. Squamous cell carcinomas showed a more delayed CE AT compared to other histopathology subtypes. However, such a difference was statistically significant with undifferentiated lung carcinomas. Conclusions. Due to an overlap of CEUS timings and patterns, dynamic CEUS parameters cannot effectively differentiate between benign and malignant peripheral pulmonary lesions. Chest CT remains the gold standard for lesion characterization and the eventual identification of other pneumonic non-subpleural localizations. Furthermore, in the case of malignancy, a chest CT is always needed for staging purposes.

Point-of-care contrast enhanced lung ultrasound and COVID-19

OBJECTIVES

Bedside lung ultrasound has been indispensable during the coronavirus disease 2019 (COVID-19) pandemic, allowing us to rapidly assess critically unwell patients. We demonstrate the unique application of contrast-enhanced ultrasound with the aim of further understanding this disease.

METHODS

Patient demographics were recorded alongside recent cross-sectional imaging and inflammatory markers. Ultrasound was conducted by experienced operators in a portable setting. Conventional six-point lung ultrasound method was used to evaluate B-lines, small (subpleural) consolidation and the pleura. Areas of small consolidation were targeted after intravenous administration of ultrasound contrast.

RESULTS

The areas of small consolidations, a potential sign of pneumonia on B-mode lung ultrasound, usually enhance on contrast-enhanced ultrasound. Our study revealed these areas to be avascular, indicating an underlying thrombotic/infarction process. Findings were present in 100% of the patients we examined. We have also shown that the degree of infarction correlates with CT severity (r = 0.4) and inflammatory markers, and that these areas improve as patients recover.

CONCLUSIONS

We confirmed the theory of immune thrombus by identifying the presence of microthrombi in the lungs of 100% of our patients, despite 79% having had a recent negative CT pulmonary angiogram study. contrast-enhanced ultrasound can be utilised to add confidence to an uncertain COVID-19 diagnosis and for prognosticating and monitoring progress in confirmed COVID-19 patients. Contrast-enhanced ultrasound is clearly very different to CT, the gold standard, and while there are specific pathologies that can only be detected on CT, contrast-enhanced ultrasound has many advantages, most notability the ability to pick up microthrombi at the periphery of the lungs.

Application value of contrast-enhanced ultrasound in the diagnosis of peripheral pulmonary focal lesions

INTRODUCTION

Peripheral pulmonary lesions are encountered frequently in clinical practice. Accurate diagnosis of these lesions is of great importance for clinicians. Ultrasound-guided lung tissue puncture is a reliable method for diagnosing these lesions.

OBJECTIVES

To investigate the application value of contrast-enhanced ultrasound (CEUS) combined with rapid on-site evaluation (ROSE) in the diagnosis of peripheral pulmonary focal lesions.

METHODS

Eighty patients enrolled from July 2020 to June 2021 were divided into two groups: a conventional ultrasound group and a CEUS group. Both groups underwent diagnostic procedures guided by ROSE to improve the success rate of puncture sampling. The success rates and complications in both groups were compared. The results for lesion enhancement, time taken for the contrast agent to reach the lesions (AT) and lung tissues (L-AT), and the difference between these times (∆AT) were compared in the CEUS group.

RESULTS

The success rate of biopsy in the CEUS group was 97.62%, which was significantly higher than that in the conventional ultrasound group (84%; P < .05). Puncture complications did not occur in the CEUS group and occurred in 5.26% of the cases in the conventional ultrasound group, but the difference was not statistically significant (P > .05). A comparison of enhancement of benign lesions and malignant lesions in the CEUS group showed a statistically significant difference (P < .05). The difference between the AT and ∆AT of benign and malignant lesions was statistically significant (P <.05). The optimal threshold of ∆AT was 2.05 s.

CONCLUSION

CEUS combined with ROSE is a very important approach for biopsy in the diagnosis of peripheral pulmonary focal lesions. CEUS has definite clinical value in the diagnosis of benign and malignant lung lesions.

Comparison of the Value of Conventional Ultrasound and Contrast-Enhanced Ultrasound-Guided Puncture Biopsy in Different Sizes of Peripheral Pulmonary Lesions

Objective

To compare the clinical value of contrast-enhanced ultrasound and conventional ultrasound-guided puncture biopsy in peripulmonary lesions of different sizes.

Materials and Methods

110 patients with peripulmonary lesions were randomly divided into two groups: the conventional ultrasound-guided group and the contrast-enhanced ultrasound-guided group. The lesions in the two groups were further divided into two groups according to the size of the lesions, and the tissues taken after puncture biopsy were sent for pathological examination. The pathological results were compared with the postoperative pathological results and other examination results, and the complications were recorded at the same time.

Results

In the conventional ultrasound group, the success rate of single puncture was 72.7% and the success rate of puncture was 80.0%; in the contrast group, the success rate of single puncture was 90.9% and the success rate of puncture was 94.6%. The difference between the two groups was statistically significant. There was no significant difference in needle bleeding and pneumothorax between the two groups. In the <30 mm group, there was no significant difference in the success rate of single puncture and the success rate of puncture between the two groups according to the size of the lesions. In the ≥30 mm group, the success rate of single puncture (97.1%) and puncture success rate (97.1%) in the contrast guidance group were higher than those in the conventional ultrasound guidance group (70.3%, 78.4%) and the difference was statistically significant (p < 0.05).

Conclusion

Compared with conventional ultrasound, for peripheral pulmonary lesions guided by contrast-enhanced ultrasonography, especially when the maximum diameter of the lesion is ≥ 30 mm, needle biopsy has better guiding significance; for peripheral lung lesions with a maximum diameter of <30 mm, contrast-enhanced ultrasonography is compared with conventional ultrasound guidance. The puncture success rate was not significantly different.

Application of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Benign and Malignant Subpleural Pulmonary Lesions

OBJECTIVE

To explore the clinical value of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of benign and malignant subpleural pulmonary lesions (SPLs).

METHODS

Among 959 patients with SPLs who were scheduled to undergo ultrasound-guided puncture in our department between January 2019 and June 2019, 506 patients were included and their B-mode ultrasound and CEUS features, including the lesion's location, size, margin, echo, perfusion pattern of ultrasound contrast agent, degree of enhancement, homogeneity, vascular signs, and necrosis, were retrospectively investigated. All malignant cases were diagnosed by pathology, while benign cases were diagnosed by two respiratory physicians after comprehensive analysis of pathology, etiology, imaging, and clinical symptoms. Statistical differences in these features between the benign and malignant groups were then analyzed.

RESULTS

There were 506 cases in this study, including 219 benign cases and 287 malignant cases. Among them, 351 were males and 155 were females, with an average age of 59 ± 16 years. There were statistically significant differences between benign and malignant groups in the perfusion pattern, the degree of enhancement, and vascular signs. The features of the malignant group included local-to-whole perfusion pattern, hypo-enhancement, and curly hair sign, while those of the benign group included a centrifugal perfusion pattern, iso-enhancement and hyper-enhancement, and dendritic sign. There was no statistically significant difference between the two groups in homogeneity and necrosis.

CONCLUSIONS

CEUS enhancement mode is different between benign and malignant SPLs, which can provide supplementary information for the differential diagnosis of SPLs in the existing imaging diagnosis.

WFUMB Technological Review: How to Perform Contrast-Enhanced Ultrasound of the Lung

The use of ultrasound has revolutionized the evaluation of pulmonary complaints and pathology. Historically, most lung ultrasound uses described are limited to B-mode, M-mode and occasionally color Doppler. However, the use of contrast can significantly expand the diagnostic capabilities of lung ultrasound. Ultrasound contrast enables significant expansion of therapeutic and intervention capabilities. We provide a detailed description of contrast administration, phases and uses in lung ultrasound. Additionally provided are example contrast use cases and illustrative examples of contrast use in a wide range of lung ultrasound applications including pneumonia, atelectasis, pulmonary embolism and neoplasms. Clinical practice examples will help providers incorporate contrast use into their lung ultrasound practice.

Perfusion Patterns of Peripheral Pulmonary Granulomatous Lesions Using Contrast-Enhanced Ultrasound (CEUS) and Their Correlation with Immunohistochemically Detected Vascularization Patterns

PURPOSE

To describe the perfusion patterns of peripheral pulmonary granulomatous lesions (PPGLs) by contrast-enhanced ultrasound (CEUS) and their correlation with vascularization patterns (VPs) represented by immunohistochemical (CD34) endothelial staining.

PATIENTS AND METHODS

From January 2007 until September 2020, 10 consecutive patients with histologically confirmed PPGLs were investigated by CEUS. The time to enhancement, classified as early pulmonary-arterial (PA) pattern of enhancement versus delayed bronchial-arterial (BA) pattern of enhancement, the extent of enhancement, classified as marked or reduced, the homogeneity of enhancement, classified as homogeneous or inhomogeneous, and the decrease of enhancement, classified as rapid washout (<120 seconds) or a late washout (≥120 seconds), were analyzed retrospectively. Furthermore, the tissue samples from the study patients and as a control group, 10 samples of normal lung tissue obtained by autopsy, and 10 samples of lung tissue with acute pneumonia obtained by autopsy were immunohistochemically stained with CD34 antibody. The presence of avascular areas (AAs) and the VPs were evaluated in all tissue samples.

RESULTS

On CEUS, all PPGLs showed a reduced inhomogeneous BA pattern of enhancement and a rapid washout (<120 seconds). On CD34 staining, all PPGLs showed central AAs in granulomas and a chaotic VP similar to angiogenesis in lung tumors. The lung tissue in control groups revealed on CD34 staining a regular alveolar VP.

CONCLUSION

The PPGLs on CEUS show an identical perfusion pattern similar to those of malignant lesions. Furthermore, for the first time, neoangiogenesis was demonstrated as a histopathological correlate to BA pattern of enhancement on CEUS.

Contrast-Enhanced Ultrasound for Evaluation of Pleural Effusion: A Pictorial Essay

B-mode ultrasound (B-US) is the standard imaging modality to evaluate pleural effusion. The value of B-US for assessing the malignancy of a pleural effusion (PE) is limited. For this purpose, computed tomography (CT) and thoracoscopy are the methods of choice to evaluate an effusion. The aim of this Pictorial Essay is to demonstrate contrast-enhanced ultrasound (CEUS) as a method in addition to B-US and CT for the evaluation of PE taking into account the clinical background. The characteristic patterns of pleural pathologies, effusion morphology, and associated lung parenchymal consolidations are presented.

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.

Perfusion Patterns of Peripheral Organizing Pneumonia (POP) Using Contrast-Enhanced Ultrasound (CEUS) and Their Correlation with Immunohistochemically Detected Vascularization Patterns

Purpose: To describe the perfusion patterns of peripheral organizing pneumonia (POP) by contrast-enhanced ultrasound (CEUS) and their correlation with vascularization patterns (VPs) represented by immunohistochemical CD34 endothelial staining. Methods: From October 2006 until December 2020, 38 consecutive patients with histologically confirmed POPs were standardized-examined by CEUS. The time to enhancement (TE; classified as an early pulmonary-arterial [PA] pattern of enhancement vs. delayed bronchial-arterial [BA] pattern of enhancement), the extent of enhancement (EE; classified as marked or reduced), the homogeneity of enhancement (HE; classified as homogeneous or inhomogeneous), and the decrease of enhancement (DE; classified as rapid washout [<120s] or late washout [≥120s]) were evaluated retrospectively. Furthermore, tissue samples from the study patients were immunohistochemically stained with CD34 antibody. The presence of avascular areas (AAs) and the VPs were evaluated in all tissue samples. Results: The majority of POPs showed a BA pattern of enhancement (71.1%), an isoechoic marked enhancement (76.3%), and an inhomogeneous enhancement (81.6%). A rapid DE was observed in 50.0% of cases. On CD34 staining, all POPs had a chaotic VP, indicating BA neoangiogenesis. AAs (abscess, necrosis, hemorrhage) were identified in (41.9%) cases with an inhomogeneous enhancement on CEUS. Conclusion: On CEUS, POPs predominantly revealed a marked inhomogeneous BA pattern of enhancement with a rapid washout in 50% of cases. Furthermore, we demonstrated that the presence of a PA pattern of enhancement, found in 28.9% of POPs, did not exclude a BA neoangiogenesis as an important feature of chronic inflammatory and malignant processes.

US Contrast Agent Arrival Time Difference Ratio for Benign versus Malignant Subpleural Pulmonary Lesions

Background US has proven valuable in the diagnosis of subpleural pulmonary lesions (SPLs); however, existing US indicators have limitations. Purpose To propose and validate a revised contrast-enhanced (CE) US indicator for differential diagnosis of benign and malignant SPLs and to compare its performance with existing CE US diagnostic criteria. Materials and Methods This prospective study (Chinese clinical trial registry, ChiCTR1800019828) enrolled patients with SPLs between May 2019 and August 2020. They were divided into a developmental cohort (DC) and a validation cohort (VC). In the DC, the optimal indicator was selected from five CE US indicators. In the VC, the selected indicator was compared with existing CE US diagnostic criteria using the area under the receiver operating characteristic curve (AUC). Pathologic analysis, microbial evidence, and clinical follow-up were used as reference standards for all SPLs. Results A total of 902 participants (DC, 424 participants; VC, 478 participants) with SPLs (mean age, 56 years ± 17; 593 men) were evaluated. The arrival time (AT) difference ratio proved to be the optimal indicator to distinguish benign from malignant SPLs. In the overall (regardless of lesion size), large (vertical diameter >3 cm), and small (vertical diameter ≤3 cm) lesion groups, the cutoff values of the AT difference ratio were 43%, 42%, and 50% and the AUCs obtained from the VC were 0.91 (95% CI: 0.88, 0.93), 0.97 (95% CI: 0.94, 0.98), and 0.77 (95% CI: 0.71, 0.83) respectively, which were higher than those of lesion-lung AT difference greater than 2.5 seconds (0.81 [P < .001], 0.85 [P < .001], and 0.7 [P = .005], respectively), lesion AT greater than 7.5 seconds (0.65 [P < .001], 0.64 [P < .001], and 0.63 [P < .001], respectively), and lesion AT greater than 10 seconds (0.67 [P < .001], 0.68 [P < .001], and 0.64 [P < .001] respectively). Conclusion The US contrast agent arrival time difference ratio enables better differentiation of benign and malignant subpleural lesions when compared with existing diagnostic criteria. Online supplemental material is available for this article. Published under a CC BY 4.0 license.

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

OBJECTIVE

To develop and prospective validate an ultrasound (US) prediction model to differentiate between benign and malignant subpleural pulmonary lesions (SPLs).

METHODS

This study was conducted retrospectively from July 2017 to December 2018 (development cohort [DC], n = 592) and prospectively from January to April 2019 (validation cohort [VC], n = 220). A total of 18 parameters of B-mode US and contrast-enhanced US (CEUS) were acquired. Based on the DC, a model was developed using binary logistic regression. Then its discrimination and calibration were verified internally in the DC and externally in the VC, and its diagnostic performance was compared with those of the existing US diagnostic criteria in the two cohorts. The reference criteria were from the comprehensive diagnosis of clinical-radiological-pathological made by two senior respiratory physicians.

RESULTS

The model was eventually constructed with 6 parameters: the angle between lesion border and thoracic wall, basic intensity, lung-lesion arrival time difference, ratio of arrival time difference, vascular sign, and non-enhancing region type. In both internal and external validation, the model provided excellent discrimination of benign and malignant SPLs (C-statistic: 0.974 and 0.980 respectively), which is higher than that of "lesion-lung AT difference ≥ 2.5 s" (C-statistic: 0.842 and 0.777 respectively, P <0.001) and "AT ≥ 10 s" (C-statistic: 0.688 and 0.641 respectively, P <0.001) and the calibration curves of the model showed good agreement between actual and predictive malignancy probabilities. As for the diagnosis performance, the sensitivity and specificity of the model [sensitivity: 94.82% (DC) and 92.86% (VC); specificity: 92.42% (DC) and 92.59% (VC)] were higher than those of "lesion-lung AT difference ≥ 2.5 s" [sensitivity: 88.11% (DC) and 80.36% (VC); specificity: 80.30% (DC) and 75.00% (VC)] and "AT ≥ 10 s" [sensitivity: 64.94% (DC) and 61.61% (VC); specificity: 72.73% (DC) and 66.67% (VC)].

CONCLUSION

The prediction model integrating multiple parameters of B-mode US and CEUS can accurately predict the malignancy probability, so as to effectively differentiate between benign and malignant SPLs, and has better diagnostic performance than the existing US diagnostic criteria.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn, identifier ChiCTR1800019828.

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 in Patients With COVID-19: Pneumonia, Acute Respiratory Distress Syndrome, or Something Else?

Coronavirus disease 2019 (COVID-19) represents a very heterogeneous disease. Some aspects of COVID-19 pneumonia question the real nature of ground glass opacities and its consolidative lesions. It has been hypothesized that COVID-19 lung involvement could represent not only a viral effect but also an immune response induced by the infection, causing epithelial/endothelial lesions and coagulation disorders. We report 3 cases of COVID-19 pneumonia in which contrast-enhanced ultrasound was suggestive of consolidations with perfusion defects, at least in part caused by ischemic or necrotic changes and not only by inflammatory or atelectasis events.

Ultrasound-guided percutaneous needle biopsy skill for peripheral lung lesions and complications prevention

Background

To investigate puncture skills and complications prevention in ultrasound-guided percutaneous needle biopsy for peripheral lung lesions.

Methods

Ninety-two peripheral lung lesions in 92 patients, detected via computed tomography (CT) and also visible on ultrasound, were retrospectively analyzed. All patients underwent percutaneous peripheral lung lesion needle biopsy under traditional ultrasound or contrast enhanced ultrasound (CEUS) guidance paying attention to avoiding necrotic areas and large blood vessels. All the specimens were examined histopathologically. Preprocedure all 92 lesions were performed by traditional ultrasonography to evaluate the size, the echogenecity, liquefaction areas and blood flow on color Doppler imaging, some of which were performed by CEUS for evaluating non-enhanced necrosis areas, contrast agent arrival time (AT) and characteristics of blood perfusion.

Results

The histopathologic results of all 92 lesions were as follows: 67 malignant tumors (including 28 adenocarcinomas, 19 squamous cell carcinomas, 6 bronchoalveolar carcinomas, 5 small cell carcinomas, 5 metastatic cancers, 3 poorly differentiated cancers and 1 malignant mesothelioma), 20 benign lesions (including 9 pneumonia, 6 inflammatory pseudotumors and 5 tuberculomas), 5 undetermined lesions. Of 52 lesions by CEUS guidance, 7 lesions showed enhancement in the pulmonary arterial-phase (including 6 pneumonia and 1 malignant tumors), 45 lesions showed enhancement in the bronchial artery phase (including 37 malignant tumors, 3 inflammatory pseudotumors, 4 tuberculomas and 1 undetermined lesion). According to needle insertion angle along linear path, a total of 92 lesions were divided into two groups, 49 lesions at an angle of 70°-80° needle insertion and 43 lesions at an angle of 80°-90° needle insertion. In the study, linear and non-linear two puncture paths were used, we first tried to puncture along linear path in all lesions, if an attempt to insert into the lesions failed due to be blocked by the ribs and then changed to puncture along non-linear path instead. The success rate of biopsy procedure along linear puncture was significantly higher at an angle of 80°-90°group (93.0% vs. 20.4%, P<0.01), and the adoption rate of non-linear path biopsy for solving the puncture needle blocked by the ribs was significantly higher at angle of 70°-80°group (79.6% vs. 7.0%, P<0.01). Of 52 lesions by CEUS guidance, 27 (51.9%) showed non enhanced necrosis areas on CEUS, only 5 showed liquefaction necrosis areas on gray-scale ultrasound. Of 40 lesions by traditional ultrasound guidance, 4 showed necrosis areas on gray-scale ultrasound. There were no significant differences in lesion size, the average number of biopsy attempts and complication rates between CEUS guidance group and traditional ultrasound guidance group (P>0.05), the pathological confirmation rate in CEUS guidance group was higher than that in traditional ultrasound guidance group, but without significant difference (98.1% vs. 90.0%, P>0.05). Of all 92 cases, 3 cases (3.3%) had mild pneumothorax and 4 cases (4.3%) had hemoptysis.

Conclusions

In ultrasound-guided needle biopsy for peripheral lung lesions, using a combination of linear and non-linear puncture techniques and keeping away from necrotic areas and large blood vessels, may help to increase the success rate and reduce the incidence of complications further.

Contrast-enhanced ultrasound features of mediastinal lymphomas and thymic epithelial tumors

OBJECTIVES

To summarize the contrast-enhanced ultrasound (CEUS) features of mediastinal lymphomas and thymic epithelial tumors (including thymomas and thymic carcinomas) and to explore the value of CEUS in the differential diagnosis of lymphomas and thymic epithelial tumors.

METHODS

Sixty-nine patients with 69 mediastinal lesions who underwent CEUS and had disease confirmed by histopathology were enrolled in the study. There were 33 cases of lymphoma, 19 cases of thymic carcinoma, and 17 cases of thymoma. CEUS features, including the enhancement pattern, enhancement distribution, enhancement time, inner necrosis status, wash out pattern, and vascular morphology, were evaluated in each group.

RESULTS

Thymomas often presented with homogeneous (88.2%, 15/17) and late (88.2%, 15/17) enhancement and a low rate of inner necrosis (17.6%, 3/17). Late (73.7%, 14/19), heterogeneous (68.4%, 13/19), and centripetal (63.2%, 12/19) enhancement were more often observed in thymic carcinoma, as was a high rate of inner necrosis (78.9%, 15/19). Lymphomas showed a homogeneous enhancement rate of 57.6% (19/33) and a late enhancement rate of 54.5% (18/33). The rate of inner necrosis for lymphomas was 45.5% (15/33). The diagnostic accuracy of this finding for distinguishing thymic epithelial tumors from lymphomas was 63.8%, the sensitivity was 80.6%, and the specificity was 45.5%. Enlarged blood vessels were a feature specific to lymphomas, while small vessels arranged in a comb shape was a feature specific to thymic epithelial tumors.

CONCLUSION

This study describes the CEUS features of common mediastinal tumors and may stimulate further studies in this field.

Application of quantitative contrast-enhanced ultrasound for evaluation and guiding biopsy of peripheral pulmonary lesions: a preliminary study

AIM

To evaluate the usefulness of contrast-enhanced ultrasonography (CEUS) in differentiating malignant from benign peripheral pulmonary lesions, and to evaluate the feasibility, accuracy, and utility of CEUS-guided biopsy for peripheral pulmonary lesions.

MATERIALS AND METHODS

Thirty-three patients with histopathologically confirmed peripheral pulmonary lesions (22 malignant, 11 benign) were enrolled in this retrospective study. Conventional ultrasound (US) was first performed and then CEUS with a contrast-specific mode and sulfur hexafluoride-filled microbubble contrast agent. CEUS indices-time of enhancement (TE), time to peak (TP), extent of peak (EP), mean transit time (MTT), area under curve (AUC), and slope-were recorded and compared between the groups. The ability of CEUS and US to detect necrotic areas within lesions was also compared and the accuracy of CEUS-guided biopsy was calculated.

RESULTS

On CEUS, TE was significantly shorter in acute pneumonia lesions than in other types of lesions (p=0.03). Other indices were not significantly different between benign and malignant lesions. Detection of necrosis within lesions was significantly higher with CEUS than with US (51.5% versus 27.3%; p=0.04). The accuracy of CEUS-guided biopsy was 96.9% (32/33).

CONCLUSION

The study findings suggest that CEUS can identify necrotic areas within lesions, and thereby, play a useful role in imaging-guided biopsy. The present pilot study indicates that CEUS may help to identify acute pneumonia lesions from other types of pulmonary lesions. CEUS might be a useful additional technique for the diagnosis of lung lesions.

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.

Contrast-Enhanced Ultrasound in Pulmonary Lymphoma: A Small Pilot Study

Here, we describe the appearance and pattern of pulmonary lymphoma on B-mode imaging and with contrast-enhanced ultrasound (CEUS). From July 2009 to December 2015, 6 patients with histologically or cytologically confirmed lymphoma of the lung were examined by B-mode imaging, followed by CEUS. A retrospective analysis of the imaging data was performed with respect to the time to enhancement, pulmonary artery (PA) and bronchial artery, echogenicity (hypoechoic, isoechoic, or hyperechoic), and homogeneity (homogeneous or inhomogeneous) of the contrast enhancement. On B-mode imaging, all 6 pulmonary lymphoma lesions were hypoechoic. Five cases had PA enhancement, and 1 case had bronchial artery enhancement on CEUS imaging. Strikingly, all 6 patients had isoechoic arterial contrast enhancement. In the parenchymal phase, 3 of the lymphoma lesions showed hypoechoic contrast enhancement, and 3 showed isoechoic enhancement. Pulmonary lymphomas are hypoechoic on B-mode imaging. With CEUS, all patients had predominant PA contrast enhancement in the arterial phase with variable parenchymal contrast enhancement. Thus, definite differentiation from other malignant or benign pulmonary lesions cannot be achieved by CEUS.

Contrast-enhanced ultrasonography characteristics of intrathoracic mass lesions in 36 dogs and 24 cats

Contrast‐enhanced ultrasonography (CEUS) is increasingly available for veterinary patients, however limited studies describe the use of this method for characterizing intrathoracic mass lesions. The aim of this prospective, observational study was to describe CEUS enhancement patterns for intrathoracic mass lesions in a sample of cats and dogs. Sixty patients (36 dogs, 24 cats) were included. Standardized CEUS examinations were performed for 41 pulmonary masses (68%) and 19 mediastinal masses (32%). Final diagnosis was based on cytology and/or histopathology. Absolute time to enhancement (TTE) values were recorded for the intrathoracic mass lesions and spleen. The spleen was used as a reference parenchymal organ to calculate relative TTE (rTTE) values. Absolute TTE of the spleen and intrathoracic mass lesions differed for dogs and cats (P = 0.001). The rTTE values significantly differed between lesions of neoplastic versus non‐neoplastic origin (P = 0.004). The majority of neoplastic pulmonary masses were supplied by bronchial arteries (63%), while most nonneoplastic pulmonary masses were supplied by pulmonary arteries (78%). The sensitivity and specificity for detecting pulmonary neoplastic masses with rTTE were 63% and 78%, respectively. Enhancement patterns for mediastinal thymomas and lymphomas significantly differed (P = 0.002). Thymomas enhanced heterogeneously in a centripetal pattern (86%), whereas lymphomas typically enhanced uniformly in a centrifugal pattern (75%). Findings indicated that CEUS is a feasible method for characterizing intrathoracic mass lesions in dogs and cats, however, the diagnostic sensitivity for detecting neoplastic pulmonary masses was low.

The feasibility of contrast enhanced ultrasonography (CEUS) in the diagnosis of non-cardiac thoracic disorders of dogs and cats

BACKGROUND

This study describes the feasibility of Contrast Enhanced Ultrasonography (CEUS) in the diagnostic work-up of non-cardiac thoracic disorders of small animals. The second aim is to assess the usefulness of CEUS as a direct guide for sample procedures.

RESULTS

Forty animals, 28 dogs and 12 cats, were included in the study. Thoracic disorders included 23 pulmonary lesions [primary carcinoma (14), lymphoma (1), sarcoma (1), histiocytic sarcoma (1), abscess (1) and pneumonia (5)] and 17 mediastinal lesions [lymphoma (8), thymoma (3), mesothelioma (1), melanoma (1), carcinomatous lymphadenopathy (1), mixsosarcoma (1), lipoma (1), and abscess (1)]. The majority of neoplastic pulmonary lesions showed an inhomogeneous distribution of contrast medium, whereas inflammatory lesions had a homogenous distribution with typical pulmonary vessels ramification. The majority of mediastinal malignant lesions showed an inhomogeneous distribution pattern. The lung and mediastinal abscesses had peripheral enhancement of the wall with an avascular center. All cytological and biopsy samples obtained after CEUS were diagnostic. Quantitative analysis, performed in 19/23 pulmonary lesions, showed a statistically significant difference (P < 0.0001) between the arrival time of the malignant (7.27 s - range 4.46-13.52 s) and benign (4.52 s - range 2.87-6.06 s) pulmonary lesions.

CONCLUSIONS

CEUS may be a useful tool for the evaluation of non-cardiac thoracic lesions. The contrast medium allows for the precise definition of lesion edges, the presence of necrotic areas, and the distribution of pulmonary vessels. Based on our preliminary results, the use of ultrasonographic contrast medium can be recommended for improving the diagnostic usefulness of cytology and biopsy sampling, because CEUS may help to define necrotic areas from viable tissue.

State of the art thoracic ultrasound: intervention and therapeutics

The use of thoracic ultrasound outside the radiology department and in everyday clinical practice is becoming increasingly common, having been incorporated into standards of care for many specialties. For the majority of practitioners, their experience of, and exposure to, thoracic ultrasound will be in its use as an adjunct to pleural and thoracic interventions, owing to the widely recognised benefits for patient safety and risk reduction. However, as clinicians become increasingly familiar with the capabilities of thoracic ultrasound, new directions for its use are being sought which might enhance practice and patient care. This article reviews the ways in which the advent of thoracic ultrasound is changing the approach to the investigation and treatment of respiratory disease from an interventional perspective. This will include the impact of thoracic ultrasound on areas including patient safety, diagnostic and therapeutic procedures, and outcome prediction; and will also consider potential future research and clinical directions.

Iris metastasis as the first sign of small cell lung cancer: A case report

The current study documents an unusual case of iris metastasis as the first sign of small cell lung cancer (SCLC) and reviews the relevant literature to increase understanding and awareness of this rare condition. A 59-year-old male chronic smoker presented with a painful and red right eye without any disturbance of vision. The patient also complained of associated chronic cough and anorexia. Upon examination, an exfoliative, pinkish-white lesion of the right iris was observed. A systemic work-up was performed, which incidentally detected metastatic SCLC in the lower lobe of the right lung and was confirmed by histopathological examination. A thorough evaluation demonstrated no organ metastases, except in the iris. Following the failure of conservative approaches, the eye had to be enucleated. The clinical features, treatment and prognosis of this condition are briefly reviewed and the results of contrast-enhanced ultrasound (CEUS) examination observed in this case are presented. Despite their rarity, iris lesions should be considered as possible manifestations of underlying malignancies. Imaging techniques, particularly CEUS, may aid the detection, diagnosis and monitoring of such lesions.

Ultrasound contrast agents

Endoscopic ultrasound (EUS) plays an important role in imaging of the mediastinum and abdominal organs. Since the introduction of US contrast agents (UCA) for transabdominal US, attempts have been made to apply contrast-enhanced US techniques also to EUS. Since 2003, specific contrast-enhanced imaging was possible using EUS. Important studies have been published regarding contrast-enhanced EUS and the characterization of focal pancreatic lesions, lymph nodes, and subepithelial tumors. In this manuscript, we describe the relevant UCA, their application, and specific image acquisition as well as the principles of image tissue characterization using contrast-enhanced EUS. Safety issues, potential future developments, and EUS-specific issues are reviewed.

Microflow imaging of contrast-enhanced ultrasound for evaluation of neovascularization in peripheral lung cancer

The aim of this study was to investigate the role of microflow imaging (MFI) of contrast-enhanced ultrasound (CEUS) for evaluating microvascular architecture of different types of peripheral lung cancer (PLC) and to explore the correlated pathological basis.Ninety-five patients with PLC were enrolled in this study. Two radiologists independently evaluated the microvascular architecture of PLC with MFI. The interobserver agreement was measured with Kappa test. The diagnosis value of MFI was calculated. With pathological analysis, the correlation between MFI and microvascular density (MVD)/microvascular diameter (MD) was evaluated.Of the 95 PLCs, MFI were mainly classified "dead wood" (27.4%, 25.3%), "vascular" (47.4%, 49.5%), and "cotton" (20.0%, 20.0%) patterns by the 2 readers. Kappa test showed a good agreement between the 2 readers (Kappa = 0.758). The "dead wood" can be regarded as a specific diagnostic factor for squamous carcinoma; the sensitivity, specificity, and accuracy was 62.9%, 93.3%, and 82.1%, respectively. The "vascular" and "cotton" patterns correlated well with adenocarcinoma and SCLC (small cell lung cancer); diagnostic sensitivity, specificity, and accuracy were 86.7%, 65.7%, and 78.9%, respectively. MVD of "dead wood" was lower than "vascular" and "cotton," while MD was bigger than the other 2 patterns (P < 0.05). There was a good correlation between MFI and histopathological types of PLC as well as between MFI and MVD/MD (P < 0.05).MFI has the advantage to display the microvascular architecture of PLCs and might become a promising diagnostic method of histopathological types of PLC. MFI features also correlated well with its pathological basis, including MVD and MD.

Role of Arrival Time Difference Between Lesions and Lung Tissue on Contrast-Enhanced Sonography in the Differential Diagnosis of Subpleural Pulmonary Lesions

OBJECTIVES

The purpose of this study was to explore the diagnostic value of the arrival time difference between lesions and surrounding lung tissue on contrast-enhanced sonography of subpleural pulmonary lesions.

METHODS

A total of 110 patients with subpleural pulmonary lesions who underwent both conventional and contrast-enhanced sonography and had a definite diagnosis were enrolled. After contrast agent injection, the arrival times in the lesion, lung, and chest wall were recorded. The arrival time differences between various tissues were also calculated.

RESULTS

Statistical analysis showed a significant difference in the lesion arrival time, the arrival time difference between the lesion and lung, and the arrival time difference between the chest wall and lesion (all P < .001) for benign and malignant lesions. Receiver operating characteristic curve analysis revealed that the optimal diagnostic criterion was the arrival time difference between the lesion and lung, and that the best cutoff point was 2.5 seconds (later arrival signified malignancy). This new diagnostic criterion showed superior diagnostic accuracy (97.1%) compared to conventional diagnostic criteria.

CONCLUSIONS

The individualized diagnostic method based on an arrival time comparison using contrast-enhanced sonography had high diagnostic accuracy (97.1%) with good feasibility and could provide useful diagnostic information for subpleural pulmonary lesions.

Contrast-enhanced ultrasonographic findings in three dogs with lung lobe torsion

Lung lobe torsion is rare but life-threatening condition in the dog. Thoracic radiographs and conventional ultrasonography cannot be conclusive for the diagnosis, and computed tomography is useful but is limited by cost and availability. This report describes the findings of contrast-enhanced ultrasonography in 3 dogs with lung lobe torsion. Contrast-enhanced ultrasonography showed the absence or reduction of pulmonary vascularization secondary to twisting of the lung lobe around its bronchovascular pedicle in all three dogs. Moreover, contrast-enhanced ultrasonography distinguished partial pulmonary atelectasis from a lung lobe torsion. These preliminary results suggest that contrast-enhanced ultrasonography can improve the accuracy of conventional ultrasonography for detection of pulmonary blood flow compromise in dogs with lung lobe torsion.

Value of Contrast-Enhanced Ultrasound in Guidance of Percutaneous Biopsy in Peripheral Pulmonary Lesions

Objectives. To investigate the value of contrast-enhanced ultrasound (CEUS) in guidance of percutaneous biopsy in peripheral pulmonary lesions. Methods. This study focused on 53 patients (male: 38, female: 15, and mean age: 55.7 years ± 10.7) with 53 single peripheral pulmonary lesions. Before core needle (16-gauge) percutaneous biopsy, CEUS were performed in all lesions, with injection of 2.4 mL SonoVue (Bracco, Italy). The contrast-enhancement pattern, display rate of internal necrosis (nonenhanced) and active (obviously enhanced) areas, biopsy success rate, and pathological diagnosis rate were recorded. Results. All the peripheral pulmonary lesions were proved pathologically as benign lesions (n = 7), primary malignancies (n = 41), or metastasis (n = 5). Forty (86.9%) malignant lesions and 4 (57.1%) benign lesions showed internal necrosis areas on CEUS. The detection rate and average size of internal necrosis areas had been significantly improved compared to conventional ultrasound (P < 0.05). After CEUS, core needle percutaneous biopsies were performed successfully in the active areas of all lesions. The sampling success rate and pathological diagnosis rate were 100% and 98.1%. Conclusions. CEUS before biopsy provided useful diagnostic information about peripheral pulmonary lesions. By depicting internal necrotic and active areas, it is a promising technique for guaranteeing the accuracy, success, and safety of core needle biopsy.

Contrast-enhanced ultrasonography in peripheral lung consolidations: What’s its actual role?

AIM: To evaluate the diagnostic accuracy of contrast-enhanced ultrasonography (CEUS) in the differential diagnosis between neoplastic and non-neoplastic peripheral pleuro-pulmonary lesions.

METHODS: One hundred patients with pleural or peripheral pulmonary lesions underwent thoracic CEUS. An 8 microliters/mL solution of sulfur hexafluoride microbubbles stabilized by a phospholipid shell (SonoVue^®) was used as US contrast agent. The clips were stored and independently reviewed by two readers, who recorded the following parameters: presence/absence of arterial enhancement, time to enhancement (TE), extent of enhancement (EE), pattern of enhancement (PE), presence/absence of wash-out, time to wash-out, and extent of wash-out. After the final diagnosis (based on histopathologic findings or follow-up of at least 15 mo) was reached, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), negative likelihood ratio (NLR) of each CEUS parameter in the differential diagnosis between neoplastic and non-neoplastic lesions were calculated. Furthermore, an arbitrary score based on the ratio between the PPVs of each CEUS parameter was calculated, to evaluate if some relationship could exist between overall CEUS behaviour and neoplastic or non-neoplastic nature of the lesions.

RESULTS: Five patients were lost at follow-up before a conclusive diagnosis was reached, 53 lesions resulted neoplastic and 42 non-neoplastic. Enhancement in the arterial phase was observed in 53/53 neoplastic lesions and 30/42 non-neoplastic lesions. On the whole, 40/42 non-neoplastic lesions showed absence of enhancement or early enhancement (95.2%) vs 3/53 neoplastic lesions (5.7%). EE was marked in 29/53 (54.7%) neoplastic lesions and 25/30 (83.3%) non-neoplastic lesions, moderate in 24/53 (45.5%) and 5/30 (16.7%), respectively. PE was homogeneous in 6/53 (11.3%) neoplastic lesions and 18/30 (60%) non-neoplastic lesions, inhomogeneous in 47/53 (88.7%) and 12/30 (40%), respectively. 19/30 (63.3%) non-neoplastic lesions enhancing in the arterial phase had no wash-out in the venous phase, 11/30 (36.7%) had late and mild wash-out. Wash-out was early in 26/53 (49%) neoplastic lesions, late in 26/53 (49%), absent in 1 (2%); marked in 16/53 (30.2%), and moderate in 36/53 (67.9%). The delayed enhancement in the arterial phase showed a sensitivity of 94.32%, specificity of 95.2%, PPV of 96.2%, NPV of 93%, PLR of 19.81, and NLR of 0.06 in identifying the neoplastic lesions. All other parameters individually considered showed unsatisfactory values of sensitivity, or specificity, or both, in differentiating neoplastic from non-neoplastic lesions. The median of the overall arbitrary score was 3 (range 0-14) in non-neoplastic lesions, and 16.5 (range 7.0-17.5) in neoplastic lesions (P < 0.001). The correlation between the diagnosis of neoplastic vs non-neoplastic lesion and the score value was statistically significant (r = 0.858, P < 0.001). Based on the score distribution, a cut-off of 7.5 enabled to reach a sensitivity of 98.1%, specificity of 95.1%, PPV 96.3%, NPV 97.5%, PVR 20.1 and NVR 0.02 in differentiating neoplastic from non-neoplastic lesions.

CONCLUSION: CEUS could be useful in the diagnostic workup of pleuropulmonary lesions. A delayed TE or a score ≥ 7.5 suggest the neoplastic nature of a lesion.

A case report of solitary fibrous tumor of the pleura: ultrasound diagnostic features

Solitary fibrous tumor of the pleura is a rarely encountered clinical entity. Although the majority of these neoplasms have a benign course, the malignant form has also been reported. We describe the case of a 57-year-old male smoker with diabetes who was incidentally diagnosed on chest X-ray with a large solitary mass of the left hemithorax. The diagnostic tests included computed tomography, ultrasound, and contrast-enhanced ultrasound. Radical surgical resection was performed and histological examination confirmed a malignant solitary fibrous tumor of the pleura. The novelty of the case is the use of contrast-enhanced ultrasound in the diagnostic workup.

Sonographically guided transthoracic biopsy of peripheral lung and mediastinal lesions: role of contrast-enhanced sonography

OBJECTIVES

The purpose of this study was to assess the impact of contrast-enhanced sonography on sonographically guided transthoracic needle biopsy of lung lesions.

METHODS

A total of 121 patients underwent sonographically guided transthoracic needle cutting biopsy. Of the 121 patients, 62 (contrast-enhanced sonography group) underwent contrast-enhanced sonography before biopsy, and the information from contrast-enhanced sonography was used to optimize the biopsy procedure. The remaining 59 patients constituted the non-contrast-enhanced sonography group. The enhancement patterns and echogenicity were evaluated by the consensus of 2 sonographers. The diagnostic efficacy was compared between the contrast-enhanced and non-contrast-enhanced sonography groups.

RESULTS

The enhancement intensity and extent varied greatly among different thoracic lesions, and an anechoic area (necrosis) was revealed in 26 of 62 lesions (41.9%) lesions after administration of the contrast agent. The overall diagnostic accuracy of sonographically guided transthoracic biopsy in this study was 85.9% (104 of 121). In the contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 58 of 62 lesions (93.6%). In the non-contrast-enhanced sonography group, the initial biopsy led to correct diagnosis in 46 of 59 lesions (78.0%). The difference in the diagnostic accuracy between the contrast-enhanced and non-contrast-enhanced sonography groups was statistically significant (P < .05).

CONCLUSIONS

Contrast-enhanced sonography enables differentiation of viable from necrotic portions of thoracic lesions and has a positive impact on the diagnostic efficacy of sonographically guided transthoracic needle biopsy.