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With a lung ultrasound (LUS) the typical findings are interstitial pneumonia. COVID-19 pneumonia is often manifested in sub-pleural areas, which is preferably detected by sonography. An RT-PCR test cannot always ensure a safe differentiation of COVID-19- and non-diseased cases. Clinically challenging is that a reliable and time efficient decision regarding COVID-19 suspects requiring isolation. Therefore, this study was aimed at evaluating the significance of LUS in symptomatic patients with COVID-19 suspicion at hospital admission. A total of 101 patients admitted to a suspect ward with COVID-19-typical symptoms were assessed. All patients received prospectively a standardized LUS at admission. Patients were classified as LUS-positive and -negative cases based on a specific LUS score. The RT-PCR test in combination with the clinical findings served as a reference. Correctly classified were 14/15 COVID-19 diseased suspects as LUS-positive (sensitivity: 93.3%). Twenty-seven out of 61 non-positive cases were classified as false positive with LUS (specificity: 55.7%). In 34/35 patients who were assessed as LUS negative, no COVID-19 disease was detected during the hospitalization. The PPV and NPV of the LUS were 34.1% and 97.1%. LUS is a valuable tool in symptomatic patients for the assessment of COVID-19-disease. The high negative predictive value of LUS is helpful to rule out the disease.

Lung ultrasound (LUS) is a practical tool for lung diagnosis when computer tomography (CT) is not available. Recent findings suggest that LUS diagnosis is highly advantageous because of its mobility and correlation with radiological findings for viral pneumonia. Simple models for both educational evaluation and technical evaluation are needed. Therefore, this work investigates the usability of a large animal model under aspects of LUS features of viral pneumonia using saline one lung flooding. Six pigs were intubated with a double-lumen tube, and the left lung was instilled with saline. During the instillation of up to 12.5 ml/kg, the sonographic features were assessed. All features present during viral pneumonia were found, such as B-lines, white lung syndrome, pleural thickening, and the formation of pleural consolidations. Sonographic findings correlate well with current LUS scores for COVID19. The scores of 1, 2, and 3 were dominantly present at 1-4-, 4-8-, and 8-12-ml/kg saline instillation, respectively. The noninfective animal model can be used for further investigation of the LUS features and can serve in education, by helping with the appropriate handling of LUS in clinical practice during management of viral pneumonia.

Objectives: Magnetic resonance imaging in pulmonary oncology is limited because of unfavourable physical and physiological conditions in ventilated lung. Previous work showed operability of One Lung Flooding using saline in vivo in MR units, and that valuable conditions for ultrasound and thermal-based interventions exist. Therefore, this study investigates the morphological details of human lung during Lung Flooding to evaluate its further value focusing on MR-guided interventions., Materials and Methods: MR imaging was performed on 20 human lung lobes containing lung cancer and metastases. Lobes were intraoperatively flooded with saline and imaged using T1w Gradient Echo and T2 Spin Echo sequences at 1.5 T. Additionally, six patients received pre-operative MRI., Results: During lung flooding, all lung tumours and metastases were visualized and clearly demarked from the surrounding lung parenchyma. The tumour mass appeared hyperintense in T1w and hypointense in T2w MR imaging. Intra-pulmonary bronchial structures were well differentiated in T2w and calcification in T1w MR sequences., Conclusion: Superior conditions with new features of lung MRI were found during lung flooding with an unrestricted visualization of malignant nodules and clear demarcation of intra-pulmonary structures. This could lead to new applications of MR-based pulmonary interventions such as laser or focused ultrasound-based thermal ablations.

Objective: Magnetic resonance imaging (MRI) of the lung remains challenging due to the low tissue density, susceptibility artefacts, unfavourable relaxation times and motion. Previously, we demonstrated in vivo that one-lung flooding (OLF) with saline is a viable and safe approach. This study investigates the feasibility of OLF in an MRI environment and evaluates the flooding process on MR images., Methods: OLF of the left lung was performed on five animals using a porcine model. Before, during and after OLF, standard T2w and T1w spin-echo (SE) and gradient-echo (GRE) sequences were applied at 3 T., Results: The procedure was successfully performed in all animals. On T1w MRI, the flooded lung appeared homogenous and isointense with muscle tissue. On T2w images, vascular structures were highly hypointense, while the bronchi were clearly demarcated with hypointense wall and hyperintense lumen. The anatomical demarcation of the flooded lung from the surrounding organs was superior on T2w images. No outflow effects were seen, and no respiration triggering was required., Discussion: OLF can be safely performed in an MR scanner with highly detailed visualization of the pulmonary structures on T2w images. The method provides new approaches to MRI-based image-guided pulmonary interventions using the presented experimental model.

Recent work has shown that One Lung Flooding (OLF) enables acoustic access to central lung tumours which can be used for non-invasive ablation using therapeutic ultrasound (HIFU). Therefore acoustic properties of flooded lung as a saline-tissue compound was determined in earlier work, which revealed that atypical acoustical condition in lung exists. Their influence on the HIFU ablation process under aspects of clinical requirements has to be investigated before clinical introduction. For this study a MATLAB based ultrasound simulation tool and a customized bioheat solver were used to determine the temporal course of HIFU induced heating with the corresponding ablation zones. This work revealed that due to the low attenuation in flooded lung the heat induction and therefore the lesion size in lung tumours is enhanced. However, HIFU raster ablation schemes should only be used for benign tumours and the volumetric ablation scheme for malignancies. A minimum power density of 0.1Wcm -3 is required during volumetric ablation to radical ablate lung tumours. The simulations indicate that up to 3 T1 (∅ 3cm) tumours with a sufficient margin (>3mm) can be ablated during one flooding session. The ablation margin is dependent upon perfusion, intra-lobular temperature, as well as ablation temperature, and can be adjusted within range of 2-6mm depending on nodule size. The acoustic conditions in flooded lung are beneficial for thermal HIFU ablation in lung but require an individualized HIFU treatment planning., (Copyright © 2018. Published by Elsevier GmbH.)

Ultrasound-guided transthoracic needle biopsy (USgTTNB) can only be used for peripheral tumours that contact the pleura. Sonographic accessibility of the entire lung can be achieved using one-lung flooding. In this study, feasibility, sensitivity and complication rate of USgTTNB of lung nodules after one-lung flooding in an ex vivo and in vivo lung tumour model were assessed. USgTTNB was performed ex vivo after one-lung flooding in 10 resected human lung lobes containing carcinoma or metastasis. USgTTNB after one-lung flooding and simulation of a lung nodule was conducted in vivo in 5 animals. Transthoracic sonography and chest X-ray were obtained 30 min after reventilation. The lungs were examined macroscopically and histopathologically. The pathologic diagnosis was confirmed in 85.7% and 100% of tumours after first and second puncture attempts, respectively. The successful puncture rate in vivo was 90%. Neither pneumothorax nor bleeding was observed. One-lung flooding enables USgTTNB of lung nodules with a high sensitivity and minimal risk of complications in a pre-clinical model., (Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Background: High intensity focused ultrasound (HIFU) has gained clinical interest as a non-invasive local tumour therapy in many organs. In addition, it has been shown that lung cancer can be targeted by HIFU using One-Lung Flooding (OLF). OLF generates a gas free saline-lung compound in one lung wing and therefore acoustic access to central lung tumours. It can be assumed that lung parenchyma is exposed to ultrasound intensities in the pre-focal path and in cases of misguiding. If so, cavitation might be induced in the saline fraction of flooded lung and cause tissue damage. Therefore this study was aimed to determine the thresholds of HIFU induced cavitation and tissue erosion in flooded lung., Methods: Resected human lung lobes were flooded ex-vivo. HIFU (1,1 MHz) was targeted under sonographic guidance into flooded lung parenchyma. Cavitation events were counted using subharmonic passive cavitation detection (PCD). B-Mode imaging was used to detect cavitation and erosion sonographically. Tissue samples out of the focal zone were analysed histologically., Results: In flooded lung, a PCD and a sonographic cavitation detection threshold of 625  Wcm - 2 ( p r  = 4, 3  MPa ) and 3.600  Wcm - 2 ( p r  = 8, 3  MPa ) was found. Cavitation in flooded lung appears as blurred hyperechoic focal region, which enhances echogenity with insonation time. Lung parenchyma erosion was detected at intensities above 7.200  Wcm - 2 ( p r  = 10, 9  MPa )., Conclusions: Cavitation occurs in flooded lung parenchyma, which can be detected passively and by B-Mode imaging. Focal intensities required for lung tumour ablation are below levels where erosive events occur. Therefore focal cavitation events can be monitored and potential risk from tissue erosion in flooded lung avoided.

Background: In recent years, high intensity focused ultrasound (HIFU) has gained increasing clinical interest as a non-invasive method for local therapy of liver malignancies. HIFU treatment of tumours and metastases in the liver dome is limited due to the adjacent ultrasound blocking lung. One-lung flooding (OLF) enables complete sonography of lung and adjoining organs including liver. HIFU liver ablation passing through the flooded lung could enable a direct intercostal beam path and thus improve dose deposition in liver. In this study, we evaluate the feasibility of an ultrasound guided transthoracic, transpulmonary HIFU ablation of liver using OLF. Methods: After right-side lung flooding, ultrasound guided HIFU was applied transthoracic- transpulmonary into liver to create thermal lesions in three pigs. The HIFU beam was targeted five times into liver, two times at the liver surface and three times deeper into the tissue. During autopsy examinations of lung, diaphragm and liver located in the HIFU path were performed. The focal liver lesions and lung tissue out of the beam path were examined histologically. Results: Fifteen thermal liver lesions were generated by transpulmonary HIFU sonication in all targeted regions. The lesions appeared well-demarcated in grey color with a cigar-shaped configuration. The mean length and width of the superficial and deeper lesions were 15.8 mm (range: 13-18 mm) and 5.8 mm (range: 5-7 mm), and 10.9 mm (range: 9-13 mm) and 3.3 mm (range: 2-5 mm), respectively. Histopathological, all liver lesions revealed a homogeneous thermal necrosis lacking vitality. There were no signs of damage of the overlying diaphragm and lung tissue. Conclusions: Flooded lung is a suitable pathway for applying HIFU to the liver, thus enabling a transthoracic, transpulmonary approach. The enlarged acoustic window could enhance the ablation speed for targets in the hepatic dome., Competing Interests: The authors declare that they have no competing interests, neither financial nor non-financial.

Background: Diaphragm motion during spontaneous or mechanical respiration hinders image-guided percutaneous interventions of tumours in lung and upper abdomen. Motion-tracking methods can be applied but increase procedure complexity and procedure time. One-lung flooding (OLF) generates a suitable acoustic pathway to lung tumours and likely suppress diaphragm motion. The aim of this study was to quantify the effect of OLF on ipsilateral diaphragm motion during contralateral one-lung ventilation., Methods: To measure the diaphragm motion, M-mode ultrasonography of the right hemidiaphragm was performed during spontaneous breathing and mechanical ventilation, as well as after right-side lung flooding, in three pigs. Diaphragm motion was analysed using magnetic resonance images during left-side lung flooding and mechanical ventilation, in four pigs., Results: Double-lung ventilation increased the diaphragm movement in comparison with spontaneous breathing (17.8 ± 4.4 vs. 12.2 ± 3.4 mm, p = 0.014). Diaphragm movement on the flooded side during contralateral one-lung ventilation was significantly reduced compared to that during double-lung ventilation (3.9 ± 1.0 vs. 17.8 ± 4.4 mm, p = 0.041). By analysing the magnetic resonance images, the hemidiaphragm on the flooded side showed an average displacement of 4.2 mm, a maximum displacement of 15 mm close to the ventilated lung and no displacement at the lateral side., Conclusion: OLF leads to a drastic reduction of diaphragm motion on the ipsilateral side which implies that targeting and motion compensation algorithms for interventions like high-intensity focused ultrasound ablation of intrapulmonary and hepatic lesions might not be required.

The usability of an ex vivo human lung model for ablation of lung cancer tissue with high-intensity focused ultrasound (HIFU) is described. Lung lobes were flooded with saline, with no gas remaining after complete atelectasis. The tumor was delineated sono-morphologically. Speed of sound, tissue density and ultrasound attenuation were measured for flooded lung and different pulmonary cancer tissues. The acoustic impedance of lung cancer tissue (1.6-1.9 mega-Rayleighs) was higher than that of water, as was its attenuation coefficient (0.31-0.44 dB/cm/MHz) compared with that of the flooded lung (0.12 dB/cm/MHz). After application of HIFU, the temperature in centrally located lung cancer surrounded by the flooded lung increased as high as 80°C, which is sufficient for treatment. On the basis of these preliminary results, ultrasound-guided HIFU ablation of lung cancer, by lung flooding with saline, appears feasible and should be explored in future clinical studies., (Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Background: High-intensity focused ultrasound is a valuable tool for minimally invasive tumour ablation. However, due to the air content in ventilated lungs, lung tumours have never been treated with high-intensity focused ultrasound. Lung flooding enables efficient lung sonography and tumour imaging in ex vivo human and in vivo porcine lung cancer models. The current study evaluates the effectiveness of lung flooding and sonography-guided high-intensity focused ultrasound for lung tumour ablation in ex vivo human and in vivo animal models., Methods: Lung flooding was performed in four human lung lobes which were resected from non-small cell lung cancers. B-mode imaging and temperature measurements were simultaneously obtained during high-intensity focused ultrasonography of centrally located lung cancers. The tumour was removed immediately following insonation and processed for nicotinamide adenine dinucleotide phosphate-diaphorase and H&E staining. In addition, the left lungs of three pigs were flooded. Purified BSA in glutaraldehyde was injected centrally into the left lower lung lobe to simulate a lung tumour. The ultrasound was focused transthoracically through the flooded lung into the simulated tumour with the guidance of sonography. The temperature of the tumour was simultaneously measured. The vital signs of the animal were monitored during the procedure., Results: A well-demarcated lesion of coagulation necrosis was produced in four of four human lung tumours. There did not appear to be any damage to the surrounding lung parenchyma. After high-intensity focused ultrasound insonation, the mean temperature increase was 7.5-fold higher in the ex vivo human tumour than in the flooded lung tissue (52.1 K ± 8.77 K versus 7.1 K ± 2.5 K). The transthoracic high-intensity focused ultrasound of simulated tumours in the in vivo model resulted in a mean peak temperature increase up to 53.7°C (±4.5). All of the animals survived the procedure without haemodynamic complications., Conclusions: High-intensity focused ultrasound with lung flooding produced a thermal effect in an ex vivo human lung carcinoma and in vivo simulated lung tumours in a porcine model. High-intensity focused ultrasound is a potential new strategy for treating lung cancer.

Background: Sonography has become the imaging technique of choice for guiding intraoperative interventions in abdominal surgery. Due to artefacts from residual air content, however, videothoracoscopic and open intraoperative ultrasound-guided thermoablation of lung malignancies are impossible. Lung flooding is a new method that allows complete ultrasound imaging of lungs and their tumours., Methods: Fourteen resected tumourous human lung lobes were examined transpleurally with B-mode ultrasound before (in atelectasis) and after lung flooding with isotonic saline solution. In two swine, the left lung was filled with 15 ml/kg isotonic saline solution through the left side of a double-lumen tube. Lung tumours were simulated by transthoracic ultrasound-guided injection of 5 ml of purified bovine serum albumin in glutaraldehyde, centrally into the left lower lung lobe. The rate of tumour detection, the severity of disability caused by residual gas, and sonomorphology of the lungs and tumours were assessed., Results: The ex vivo tumour detection rate was 100% in flooded human lung lobes and 43% (6/14) in atelectatic lungs. In all cases of atelectasis, sonographic tumour imaging was impaired by residual gas. Tumours and atelectatic tissue were isoechoic. In 28% of flooded lungs, a little residual gas was observed that did not impair sonographic tumour imaging. In contrast to tumours, flooded lung tissue was hyperechoic, homogeneous, and of fine-grained structure. Because of the bronchial wall three-laminar structure, sonographic differentiation of vessels and bronchi was possible. In all cases, malignant tumours in the flooded lung appeared well-demarcated from the lung parenchyma. Adenocarcinoma, squamous, and large cell carcinomas were hypoechoic. Bronchioloalveolar cell carcinoma was slightly hyperechoic. Transpleural sonography identifies endobronchial tumour growth and bronchial wall destruction. With transthoracic sonography, the flooded animal lung can be completely examined in vivo. There is no residual gas, which interferes with ultrasound. Pulmonary vessels and bronchi are clearly differentiated. Simulated lung lesions can easily be detected inside the lung lobe., Conclusions: Lung flooding enables complete lung sonography and tumour detection. We have developed a novel method that efficiently uses ultrasound for guiding intraoperative interventions in open and endoscopic lung surgery.

Objective: The LigaSure device has been demonstrated to be safe for systemic vessels up to 7 mm in diameter, although its use in thoracic surgery remains understudied. We aimed to evaluate the safety of LigaSure for pulmonary artery sealing., Methods: In 30 cases of open lung lobectomy, 15 small pulmonary arteries (diameter, 3-5 mm) and 15 thick pulmonary arteries (diameter, 6-8 mm) were divided with LigaSure. Before closure of the thoracotomy, the vessel stumps were ligated proximal to the sealing zone, resected, and preserved in formaldehyde for histopathologic examination. In a control group, a similar number and size of pulmonary arteries were suture-ligated. The burst pressure of the pulmonary arteries from the resected lung lobes was measured., Results: The mean burst pressure of small pulmonary arteries was 4.3-fold less after sealing than after ligation (315 ± 213.1 mm Hg vs 1345 ± 256 mm Hg; P < .001), and 6.4-fold less than after ligation of thick pulmonary arteries (156 ± 42.5 mm Hg vs 1007 ± 141.6 mm Hg; P < .001). Sealed pulmonary arteries >5 mm in diameter have a burst pressure that is 50% less than that of smaller arteries (P < .001). In all cases after sealing, the histologic examination demonstrated only a fusion of the adventitia, whereas the intima and media were replaced and invaginated into the vessel lumen., Conclusions: LigaSure does not result in complete fusion of the wall layers of pulmonary arteries. The pulmonary artery burst pressure after sealing is significantly less compared with conventional suture ligation. It remains unclear whether these findings create a clinical risk of rupture., (Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Background and Purpose: Cystic medionecrosis is characterized by degeneration of elastic and collagenous fibers in the media and predominantly involves the thoracic aorta. This rare disease is usually manifested clinically by a dissecting aneurysm. Cystic medionecrosis as a cause of moderate stenosis of the carotid artery in a patient having a stroke has not been reported., Summary of Case: We report a case of a man who had a cerebral infarction caused by medium-degree stenosis of the left internal carotid artery. Duplex sonography and magnetic resonance imaging revealed no typical signs of dissection. The stenosis was caused by cystic medionecrosis that involved only the carotid bifurcation with microdissection, predominantly older intramural hemorrhage, and fresh intraluminal thrombotic deposits., Conclusions: Patients with cystic medionecrosis may have a stroke due to short-track stenosis of the internal carotid artery.

Background: Thoracoscopic resection of indeterminate pulmonary nodules is most commonly performed through three trocars using an endoscopic stapler. We assessed the safety, feasibility, and results of laser resection via minimal access under only local anesthesia., Methods: Between September 2009 and June 2010, excision of subpleural nodules using laser application under only local anesthesia was performed in 28 patients (Laser group). A 2-mm trocar (minigrasper) and an 11-mm trocar (operating scope) were used. Anesthesia time, surgery time, global operating room time, chest tube time, piritramid dose, and hospital stay were assessed and compared with data from a patient group (n = 28) that required nodule resection through three trocars using an endoscopic stapler under general anesthesia (Control group)., Results: There was no mortality or major morbidity. There was no difference in technical feasibility between the groups. Two patients in the Laser group and one patient in the Control group required conversion to thoracotomy due to severe adhesions. The mean nodule size was 0.9 ± 0.2 cm in the Laser group and 1.0 ± 0.3 cm in the Control group (P = 0.05). Comparisons of Laser group results with Control group results showed that in the Laser group, anesthesia time (3 ± 0.7 vs. 42 ± 6.3 min, P < 0.001), global operating room time (51 ± 4.8 vs. 88 ± 10.8 min, P < 0.001), piritramid dose (65.9 ± 30.5 vs. 109.1 ± 21.9 mg, P < 0.001), and hospital stay (2.3 ± 0.9 vs. 3.2 ± 0.6 days, P < 0.001) were significantly reduced. Patients' satisfaction was high. Ninety-eight percent of patients said they would undergo this surgery again., Conclusion: Awake thoracoscopic laser resection of subpleural pulmonary nodules proved safe and feasible. This technique may enable further reduction of invasiveness, length of hospital stay, and costs in selected patients.

In patients with diabetes, a popliteocrural vein bypass frequently must be linked to the distal peroneal artery. To reduce trauma to the ischemically damaged tissue, we used a dorsal approach to the peroneal artery. With the patient prone, a incision parallel to the posterolateral margin of the Achilles tendon is made. After the deep crural fascia and flexor hallucis longus are split, access to the peroneal artery is easily obtained. The second segment of the popliteal artery is exposed in the popliteal cavity. The small saphenous vein is left in situ and anastomosed with the arteries after proximal and distal preparation and valvulotomy.

Rationale and Objectives: To determine the effect of radiofrequency (RF) ablation on normal lung tissue in an animal model., Materials and Methods: RF ablation of lung tissue was performed on eight swine under computed tomographic control. Group A (n = 4) received peripheral ablation (subpleural needle placement) and group B (n = 4) received central ablation (hilar needle placement). RF ablation was applied via a single 4.5-gauge internally cooled electrode with a 2-cm tip for 12 minutes. The ablation was monitored with computed tomography at 3, 7, and 12 minutes, and 10 minutes after ablation. After 3, 7, 40, and 60 days, computed tomography was performed, and the animals were sacrificed to examine the lung tissue both macroscopically and histopathologically., Results: There were no deaths from RF ablation. In group A, coagulative necrosis was resorbed almost completely and transformed into a fibrotic scar after 60 days. No pneumothorax, pleural effusion, or lung abscess was observed. In group B, there was also a transformation of the necrosis into connective tissue. Neither the pulmonary vessels nor the bronchi of the hilum abutting the coagulative necrosis were damaged. After 60 days, no vascular thrombosis, bleeding, aneurysm, bronchial stenosis, or bronchopulmonary fistula was observed., Conclusion: RF ablation of lung tissue affects coagulation necrosis, causing scar transformation. There was no damage to either great vessels or bronchi. The application of RF ablation for tumors located in or near functional structures appears feasible without severe complications., (Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.)

Background: Patients with T4 non-small cell lung cancers with limited involvement of mediastinal structures can undergo resection, with acceptable long-term survival. Computed tomography has not proven to be reliable in determining the operability of locally advanced lung carcinoma. This study evaluated the ability of video-assisted thoracoscopy alone and with endothoracic sonography to determine operability., Methods: Computed tomography showed a close contact of the tumor with mediastinal structures (T4) in 155 patients. Staging was expanded with video-assisted thoracoscopy, followed by thoracoscopic ultrasound. Lateral thoracotomy with hilar and mediastinal dissection was considered the gold standard in determining operability., Results: Thoracoscopic ultrasound, compared with thoracoscopy alone and computed tomography, had the highest sensitivity (94.1% vs 75.2% vs 43.6%, p < 0.001) and specificity (98.1% vs 57.4% vs 37.0%, p < 0.001) for determining operability. Computed tomography, thoracoscopy, and thoracoscopic ultrasound were falsely negative in 57 (36.8%), 25 (16.1%), and 6 (3.9%) patients and falsely positive in 34 (21.9%), 23 (14.8%), and 1 (0.6%). False-negative results for operability by thoracoscopic ultrasound were found only in tumors involving the left atrium (3.9%)., Conclusions: Estimation of operability in locally advanced lung cancer can be improved with video-assisted thoracoscopy and ultrasound. More than one-third of patients classified as inoperable by computed tomography were able to undergo complete resection., (Copyright 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)