Applications of colour Doppler ultrasound in the diagnosis of chest diseases

Case report: Application of color Doppler sonography for the assessment of pulmonary consolidations in a dog

A 1,5-year-old male Maltipoo was presented to the emergency service for dyspnea, weakness, and cough. An echocardiographic examination showed evidence of pulmonary hypertension with a McConnell sign. Lung ultrasound, including color Doppler, was performed and identified two distinct populations of lung consolidation. Color Doppler analysis of the first type of consolidation showed the absence of blood flow within regions of the consolidation and flow amputation. These findings were consistent with the "vascular sign" reported in human medicine and prompted consideration of pulmonary thromboembolism as a differential diagnosis. In the second type of consolidation, color Doppler identified blood flow within the pulmonary vessels of the consolidated lung, forming a "branching tree-like" pattern that followed the anatomical course of the pulmonary vasculature. These findings suggested that blood flow was preserved within the pulmonary vasculature of the consolidated lung and prompted consideration of inflammatory causes of pulmonary pathology. On recheck 6 days later, recanalization of the first type of consolidation was identified with color Doppler. The case was followed serially once a month for 5 months with LUS, which showed continued improvement. Based on a positive fecal Baermann test, a final diagnosis of Angiostrongylus vasorum was made. New or Unique information Provided-this is the first report of color Doppler LUS being used to characterize and help differentiate the cause of lung consolidation in dogs.

Application of Transthoracic Shear Wave Elastography in Evaluating Subpleural Pulmonary Lesions

AIM

The objective of this research was to investigate the feasibility of transthoracic shear wave elastography in the differentiation of subpleural masses.

METHODS

Between December 2019 and November 2020,82 consecutive patients with radiographic evidence (including chest X ray and thoracic computed tomography CT) of single subpleural lesion enrolled in this research. The Young's modulus E (including E_mean and E_max) of each lesion was detected, and the Young's modulus E of malignant lesions were compared with those of benign ones. We made diagnoses according to the results of pathology or standard clinical course for at least 3 months. Receiver operating characteristic (ROC) analysis was plotted to determine the cut-off point by maximizing the Youden index.

RESULTS

The E_mean and E_max of the benign and malignant group was 34.68 ± 12.12 kPa vs. 53.82 ± 11.95 kPa (p < 0.001), 57.77 ± 14.45 kPa vs. 76.62 ± 17.04 kPa (p < 0.001). The ROC of E_mean showed that when the cut-off point was 43.8 kPa, the Youden index (0.53) for distinguishing benign and malignant tumors was the largest (sensitivity 80.4 %, specificity 72.2 %, AUC = 0.848, p < 0.0001). When the cut-off point recommended by E_max ROC was 73.5 kPa, the Youden index (0.44) for distinguishing benign and malignant tumors was the largest (sensitivity 76.1 %, specificity 66.7 %, AUC = 0.780, p < 0.0001).

CONCLUSIONS

This study demonstrated that we can employ transthoracic shear wave elastography as a valuable instrument in differentiating benign subpleural lesions from malign ones.

Application of transthoracic shear-wave ultrasound elastography in lung lesions

INTRODUCTION

Tissue stiffness information may help in the diagnosis of lung lesions. This study aimed to investigate and validate the application of transthoracic two-dimensional shear-wave ultrasound elastography in differentiating malignant from benign subpleural lung lesions.

METHODS

This study involved one retrospective observational derivation cohort from January 2016 to December 2017 and one prospective observational validation cohort from December 2017 to December 2019. The inclusion criterion was radiographic evidence of pulmonary lesions. The patients were categorised into air bronchogram and hypoechoic groups based on B-mode grayscale images. The elasticity of subpleural lung lesions with acceptable shear-wave propagation was measured. Diagnoses were made on the basis of pathology, microbiological studies or following up the clinical course for at least 6 months.

RESULTS

A total of 354 patients were included. Among the 121 patients in the derivation cohort, a receiver operating characteristic curve was constructed and the cut-off point to differentiate benign from malignant lesions was 65 kPa with a Youden index of 0.60 and an accuracy of 84.3%. Among the 233 patients in the validation cohort, the diagnostic performance was maintained, with a Youden index of 0.65 and an accuracy of 86.7%. Upon applying the cut-off point to the air bronchogram group, the Youden index was 0.70 and the accuracy was 85.0%.

CONCLUSIONS

This study validated the application of transthoracic shear-wave ultrasound elastography for assessing lung malignancy. A cut-off point of 65 kPa is suggested for predicting lung malignancy. Furthermore, for pulmonary air bronchogram lesions with high elasticity, tissue proofing should be considered because of the high possibility of malignancy.

Transthoracic Ultrasound Elastography in Pulmonary Lesions and Diseases

Ultrasound elastography has shown promising result in the diagnosis of various diseases; however, its application for pulmonary diseases has yet to be clarified. This study aimed to assess the application and feasibility of ultrasound elastography in various pulmonary lesions and diseases. We enrolled 45 patients with radiographic evidence of pneumonia, tumors or obstructive pneumonitis, and 70 ultrasonic lesions were identified (eight necrosis, 17 atelectasis, seven consolidation and 38 tumors). Ultrasound elastography was performed and the strain ratio, which is the ratio of strain of the reference tissue to an equally measuring region of interest of a lesion, was measured. The strain ratio was significantly different among lesions with different ultrasound morphologies (1.03 ± 0.71 [necrosis] vs. 2.51 ± 1.14 [atelectasis] vs. 19.98 ± 15.59 [consolidation] vs. 36.19 ± 20.18 [tumor]; p < 0.05). The strain ratio of primary lung cancer was also significantly different from pneumonia (p = 0.023) and metastatic lung cancer (p = 0.015). In conclusion, transthoracic ultrasound elastography can differentiate pulmonary lesions with different ultrasound morphologies. ClinicalTrials.gov Identifier: NCT02636985.

Predictive value of Doppler ultrasound in childhood pneumonia

This study aimed to determine the predictive value of intercostal and pulmonary artery Doppler flow patterns in the outcome of childhood pneumonia. Pneumonia was classified according to type of pleural effusion and the ultrasound features of consolidations. Doppler flow patterns of intercostal and pulmonary arteries were analysed and correlated with pneumonia type and hospital stay. Of 83 pneumonia cases, 55 were uncomplicated and 28 were complicated. Pleural effusion was present in 54 cases, with 29 non-septated and 25 septated cases. Patients with uncomplicated pneumonia did not have abnormal Doppler flow patterns, compared with 64% (18 of 28) of patients with complicated pneumonia. Doppler ultrasound patterns in childhood pneumonia were correlated with pneumonia type and may be predictive of pneumonia outcome.

Ultrasound-guided pigtail catheters for drainage of various pleural diseases

OBJECTIVE

Little is known about the efficacy and safety of ultrasound-guided pigtail catheters for the management of various pleural diseases in the emergency department, ward, and intensive care unit.

METHODS

We conducted a retrospective study in a university hospital during a 1-year interval.

RESULTS

A total of 276 patients (178 men and 98 women) underwent 332 pigtail catheters (the drain size ranged from 10F to 16F) under ultrasound guidance. The mean ± SEM patient age was 59 ± 18 years, and mean duration of drainage was 6.1 ± 2 days. A total of 64 drains (19.2%) were inserted for pneumothoraces; 98 drains (29.5%), for malignant effusions; 119 drains (35.8%), for parapneumonic effusions/empyemas; and 38 drains (11.4%), for massive transudate pleural effusions. The overall success rate was 72.9%. The success rate was highest when the drain was used to treat massive transudate effusions (81.6%) and malignant pleural effusions (75.5%), followed by parapneumonic effusions/empyemas (72.2%), hemothoraces (66.6%), and pneumothoraces (64.0%). Only 10 (3.0%) drains had complications due to the procedure, including infection (n = 4, 1.2%), dislodgment (n = 4, 1.2%), wound bleeding at the pigtail catheter puncture area complicated with hemothoraces (n = 1, 0.3%), and lung puncture (n = 1, 0.3%). There was no significant difference in success rate when different catheter sizes were used to treat pleural diseases.

CONCLUSIONS

Ultrasound-guided pigtail catheters provide a safe and effective method of draining various pleural diseases. We strongly suggest that ultrasound-guided pigtail catheters be considered as the initial draining method for a variety of pleural diseases.

Pediatric chest ultrasound

Ultrasound examination of the thorax can be quite rewarding in children, because their unique thoracic anatomy provides many acoustic windows into the chest. With only a modest effort, chest ultrasonography can provide many clinically relevant answers, without the radiation exposure from CT, or the need for sedation sometimes required for CT and MR imaging.

Ultrasound in the diagnosis and management of pleural disease

The authors summarize the current applications of chest ultrasonography in the diagnosis and management of various pleural diseases. Ultrasound has been proved to be valuable for the evaluation of a wide variety of chest diseases, particularly when the pleural cavity is involved. Chest ultrasound can supplement other imaging modalities of the chest and guides a variety of diagnostic and therapeutic procedures. Pleural effusion, pleural thickening, pleural tumors, tumor extension into the pleura and even the chest wall, pleuritis, and pneumothorax can be detected easily and accurately with chest ultrasound. Many ultrasound features and signs of these diseases have been well characterized and widely applied in clinical practice. Under real-time ultrasound guidance the success rates of invasive procedures on pleural diseases increase significantly whereas the risks are greatly reduced. The advantages of low-cost, bedside availability and no radiation exposure have made ultrasound an indispensable diagnostic tool in modern pulmonary medicine.

Congenital cystic lung disease: diagnostic and therapeutic considerations

Congenital lung cysts such as congenital cystic adenomatoid malformation, pulmonary sequestration, congenital lobar emphysema, and bronchogenic cysts are rare but fascinating anomalies of lung development. While there are many similarities in terms of their presenting features, there are particular differences between the diagnostic groups that are important to highlight, especially in relationship to approaches to imaging and long-term outcome. A case of each entity is presented with an emphasis on the contemporary approach to diagnostic investigations and therapeutic options.

Posterior mediastinal arteriovenous malformation with atypical color Doppler sonographic findings

An arteriovenous malformation (AVM) is an anomaly of capillary development that results in a direct connection between branches of an artery and veins, with no intervening capillary network. A definite diagnosis of AVM is usually made with angiography. We report the case of a posterior mediastinal AVM found on routine sonography in a 64-year-old woman with neglected hypertension and severe back pain. Color Doppler imaging showed 2 adjoined vascular structures without a typical mosaic-like flow pattern, and spectral Doppler analysis showed low-resistance flow and arteriovenous shunting in 2 adjoined vascular structures. The diagnosis was subsequently confirmed by angiography. Because disastrous bleeding could result if needle biopsy were performed inadvertently in the case of a suspected mediastinal AVM, we suggest that color Doppler sonography be attempted if there is an adequate acoustic window.

Ultrasound-guided transthoracic biopsy of the chest

Recent studies have confirmed that US is a very useful diagnostic tool for various diseases of the chest. The image information provided by US is helpful for etiologic diagnosis and clinical management. US-guided needle biopsy provides a precise and safe approach for transthoracic tissue sampling of lesions. The diagnostic yield is high, and the procedure is relatively easy and very safe. Color Doppler US and amplitude US angiography further extend the diagnostic potential and safety of this invasive procedure. Vascular information can be obtained and the needle shaft can be visualized clearly while conducting a biopsy. US examination and US-guided needle aspiration biopsy have now become indispensable diagnostic tools for various chest diseases.