Subsegmental Level Research Articles

Computed tomography identifies sex-specific differences in surgical chronic thromboembolic pulmonary hypertension

BackgroundRegistry data suggests women are less likely than men to undergo pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension despite a similar proportion of proximal versus distal disease. We hypothesized that sex-specific differences could be elicited with a computed tomography pulmonary angiography analysis beyond proximal versus distal. MethodsPreoperative computed tomography pulmonary angiography of patients who underwent pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension from January 2017 to September 2021 were analyzed. The pulmonary vascular tree was divided into 32 named vessels with chronic thromboembolism presence and lesion type recorded for each vessel. If no lesion was identified in a segmental vessel, subsegmental disease was recorded when present. Results144 patients (mean age 57 ± 15 years, 78 women) were included. There were no sex differences in baseline hemodynamics. Men had more vessels involved than women (mean 20.3 vs 17.1, p=0.004) and had fewer disease-free pulmonary segments (mean 4.9 ± 4.3 vs 7.6 ± 5.5, p=0.001). Men had a greater number of webs, eccentric thickening, and occlusions. The distribution of lesion type did not significantly differ between sexes at the main or lobar level but men had significantly more lesions in the segmental vasculature while women had a higher proportion of subsegmental lesions (p<0.001). ConclusionSex-specific differences in chronic thromboembolic pulmonary hypertension are demonstrated on computed tomography pulmonary angiography in overall distribution and lesion type at the segmental and subsegmental level with women having fewer and more distal lesions despite similar hemodynamics.

CT venography for the diagnosis of postpartum venous thromboembolism: a prospective multi-center cohort study.

To assess the role of CT venography (CTV) in the diagnosis of venous thromboembolism (VTE) during the postpartum period. This multicenter prospective cohort study was conducted between April 2016 and April 2020 in 14 university hospitals. All women referred for CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE) within the first 6 weeks postpartum were eligible. All CTPAs were performed on multidetector CT machines with the usual parameters and followed by CTV of the abdomen, pelvis, and proximal lower limbs. On-site reports were compared to expert consensus reading, and the added value of CTV was assessed for both. The final study population consisted of 123 women. On-site CTPA reports mentioned PE in seven women (7/123, 5.7%), all confirmed following expert consensus reading, three involving proximal pulmonary arteries and four limited to distal arteries. Positive CTV was reported on-site in nine women, five of whom had negative and two indeterminate CTPAs, bringing the VTE detection rate to 11.4% (14/123) (95%CI: 6.4-18.4, p = 0.03). Expert consensus reading confirmed all positive on-site CTV results, but detected a periuterine vein thrombosis in an additional woman who had a negative CTPA, increasing the VTE detection rate to 12.2% (15/123) (95%CI: 7.0-19.3, p = 0.008). Follow-up at 3 months revealed no adverse events in this woman, who was left untreated. Median Dose-Length-Product was 117 mGy.cm for CTPA and 675 mGy.cm for CTPA + CTV. Performing CTV in women suspected of postpartum PE doubles the detection of venous thromboembolism, at the cost of increased radiation exposure. CTV can help in the decision-making process concerning curative anticoagulation in women with suspected postpartum PE, particularly those whose CTPA results are indeterminate or whose PE is limited to the subsegmental level. Postpartum women are at risk of pulmonary embolism, and CT pulmonary angiography can give equivocal results. CT venography (CTV) positivity increased the venous thromboembolism detection rate from 5.7 to 11.4%. CTV may help clinical decision-making, especially in women with indeterminate CTPA results or subsegmental emboli.

Role of MRI in diagnosis of pulmonary embolism

BackgroundPulmonary embolism (PE) is considered a serious condition and has clinical challenges in diagnosis. Computed tomography pulmonary angiography (CTPA) is considered the gold standard in PE diagnosis. Contrast-enhanced MRA also has a strong useful role in the diagnosis. Our study aims to assess the role of non-contrast MRA in diagnosis of acute pulmonary embolism compared to either CT pulmonary angiography or contrast enhanced MRA.ResultsIn total, 50 patients with PE confirmed by either CTPA or CE-MRA were included in this study. All patients underwent non-contrast MRPA during the three consecutive days after CTPA or at the same examination setting in CE-MRA. The results were compared and statistically analyzed.The mean age of our study group was 47.80 ± 14.01 years. Males represented 56% (28/50) and females 44% (22/50). The per-vessel sensitivity, specificity and accuracy of non-contrast MRPA reached about 100% for each parameter at the level of the pulmonary trunk, main pulmonary and lobar arteries. At the segmental level, sensitivity, specificity, and accuracy reached about 88%, 100%, and 94%, while at the subsegmental level, about 35%, 100%, and 66% respectively. The overall sensitivity, specificity, and accuracy of non-contrast MRPA regardless of the site were 84%, 100%, and 90% respectively.ConclusionsNon-contrast pulmonary MRA has a high sensitivity and specificity in the diagnosis of PE, especially in proximal pulmonary arteries. So, it can be used as an alternative to the CTA and CE-MRA, especially when the CTA and the use of gadolinium are contraindicated.

An atlas of anatomical variants of subsegmental pulmonary arteries and recognition error analysis.

Surgery, including lobectomy and segmentectomy, is the major curative intervention for lung cancer. Surgical planning for pulmonary surgery is difficult due to the high variation rate of pulmonary arteries and needs a fine-grained atlas as a reference. We conducted a study to create a surgically oriented atlas and analyzed the error encountered during the production. A total of 100 Chest CTs performed at Peking University People's Hospital from 2013.09 to 2020.10 were randomly selected for segmental artery labeling. Dicom files were collected for 3D reconstruction. Manual segmentation of each segmental artery was performed by 4 thoracic surgeons. Cross-validation by surgeons was performed to establish the golden standard based on their consensus. Initial recognition errors were recorded accordingly. The most frequently seen variants for the right upper lobe is 2-branch RA1+2rec+3 and RA2asc; right middle lobe 2-branch RA4a and RA4b+5; right lower lobe 3-branch RA7, RA8 and RA9+10; left upper lobe 3-branch LA1+2a+3, LA1+2b, LA1+2c and 1-branch LA4+5; left lower lobe 2-branch LA8 and LA9+10. Top 5 segmental error occurs in RA4 (23%), LA8 (17%), RA9 (17%), RA8 (14%) and LA9 (11%). A rapid surgical planning tool form was created based on high frequency anatomic variants. Our research provided an atlas for lobectomy and segmentectomy at the subsegmental or more distal level. We demonstrated that the recognition accuracy of pulmonary arteries in a non-time-sensitive experimental scenario was still unfavorable. We also suggest that extra attention should be paid to certain surgeries during the surgical planning process.

Distal vessel pulmonary thromboendarterectomy: Results from a single institution

Chronic thromboembolic pulmonary hypertension (CTEPH) is primarily managed by pulmonary thromboendarterectomy (PTE). As advanced surgical techniques permit resection at the segmental and subsegmental level, PTE can now be curative for CTEPH mostly involving the distal pulmonary arteries. Between January 2017 and June 2021, consecutive patients undergoing PTE were categorized according to the most proximal level of chronic thrombus resection: Level I (main pulmonary artery), Level II (lobar), Level III (segmental) and Level IV (subsegmental). Proximal disease patients (any Level I or II) were compared to distal disease (Level III or IV bilaterally) patients. Demographics, medical history, preoperative pulmonary hemodynamics, and immediate postoperative outcomes were obtained for each group. During the study period, 794 patients underwent PTE, 563 with proximal disease and 231 with distal disease. Patients with distal disease more frequently had a history of an indwelling intravenous device, splenectomy, upper extremity thrombosis or use thyroid replacement and less often had prior lower extremity thrombosis or hypercoagulable state. Despite more use of PAH-targeted medications in the distal disease group (63.2% vs 50.1%, p < 0.001), preoperative hemodynamics were similar. Both patient groups exhibited significant improvements in pulmonary hemodynamics postoperatively with comparable in-hospital mortality rates. Compared to proximal disease, a lower percentage of patients with distal disease showed residual pulmonary hypertension (3.1% vs 6.9%, p=0.039) and airway hemorrhage (3.0% vs 6.6%, p=0.047) postoperatively. Thromboendarterectomy for distal (segmental and subsegmental) CTEPH is technically feasible and may result in favorable pulmonary hemodynamic outcomes, without increased mortality or morbidity.

Diagnostic value of hybrid perfusion SPECT/CT and CTPA for detection of pulmonary embolism

The diagnosis of pulmonary embolism (PE) employs a combination of clinical assessment, D-dimer assay and imaging with pulmonary ventilation-perfusion (V/P) scintigraphy and/or computed tomography pulmonary angiography (CTPA). It is generally accepted that V/P SPECT and CTPA have high diagnostic accuracy. Nonetheless, there are only limited data directly comparing these two modalities. This prospective cross-sectional study included 184 hospitalized patients with clinically suspected PE. Clinical assessment, electrocardiography (ECG), vein ultrasound, echocardiography, arterial blood gas test, D-dimer assay, perfusion single photon-emission computed tomography/computed tomography (P-SPECT/CT) and CTPA were carried out. PE was diagnosed in 109 of 146 patients (74.66%) by P-SPECT/CT and 47 of 89 patients (52.81%) by CTPA. The sensitivity and specificity of P-SPECT/CT were 82.9%, respectively, 64.7%. The positive predictive value of SPECT/CT was 94.7%, the negative predictive value was 33.3% and the validity was 80.8%. For CTPA the sensitivity was 58.2% and specificity 90%. The positive predictive value of CTPA was 97.9%, the negative predictive value 21.4% and the accuracy (performance) 61.8%. There was no significant difference between the two methods regarding the diagnosis of PE at sub-segmental and segmental level. The sensitivity of P-SPECT/CT was significantly higher compared with CTPA, whereas the specificity was significantly higher at CTPA for diagnosis of PE. The P-SPECT/CT showed excellent diagnostic performance with high sensitivity and a very high positive predictive value. Thus, it could serve as first-line imaging for PE in the number of prevalent cases.

TNN: Tree Neural Network for Airway Anatomical Labeling.

Detailed anatomical labeling of bronchial trees extracted from CT images can be used as fine-grained maps for intra-operative navigation. To cater to the sparse distribution of airway voxels and large class imbalance in 3D image space, a graph-neural-network-based method is proposed to map branches to nodes in a graph space and assign anatomical labels down to subsegmental level. To address the inherent problem of overlapping distribution of positional and morphological features, especially for subsegmental categories, the proposed method focuses on the relative position between sibling subsegments which is fixed in most cases. The hierarchical nomenclature is represented by multi-level labeling and each category is associated with one or two subtrees in the graph. Hyperedges are used to extract the representation of subtrees while a hypergraph neural network is developed to encode their intrinsic relationship through hyperedge interaction. A filter module is further designed to guide feature aggregation between nodes and hyperedges. With the proposed method, the final accuracies for segmental and subsegmental node classification can achieve 93.6% and 82.0% respectively. The corresponding code is publicly available at https://github.com/haozheng-sjtu/airway-labeling.

Bronchial atresia presenting with two bronchoceles

Bronchial atresia is a rare congenital lung abnormality characterized by the focal obliteration of the bronchial lumen, on a lobar, segmental or subsegmental level, usually associated with peripheral mucus impaction (bronchocele or mucocele) [1,2]. It presents with adjacent segmental or subsegmental hyperinflation, and reduction of vascularization of the involved segment or lobe.

“Triple low” free-breathing CTPA protocol for patients with dyspnoea

To assess the performance of a "triple-low" free-breathing protocol for computed tomography pulmonary angiography (CTPA) evaluated on patients with dyspnoea and suspected pulmonary embolism and discuss its application in routine clinical practice for the study of the pulmonary parenchyma and vasculature. This study was conducted on a selected group of dyspnoeic patients referred for CTPA. The protocol was designed using fast free-breathing acquisition and a small, fixed volume (35 ml) of contrast agent in order to achieve a low-exposure dose. For each examination, radiodensity of the pulmonary trunk and ascending aorta, and the dose-length product (DLP) were recorded. A qualitative analysis was performed of pulmonary arterial enhancement and the pulmonary parenchyma. This study included 134 patients. Contrast enhancement of the pulmonary arteries (409±159 HU) was systematically >250 HU. The duration of acquisition ranged from 0.9 to 1.3 seconds for free-breathing imaging. The mean DLP was in the range of low-dose chest CT acquisitions (145±73 mGy·cm). The analysis was deemed optimal in 90% (120/134) of cases for the pulmonary parenchyma. Sixty-nine per cent (92/134) of cases demonstrated homogeneous enhancement of the pulmonary arteries to the subsegmental level. Only 6% (8/134) of examinations were considered uninterpretable. The present "triple-low" CTPA protocol allows convenient analysis of the pulmonary parenchyma and arteries without hindrance by respiratory motion artefacts in dyspnoeic patients.

Flexible fibre optic bronchoscopy as angioscope to ascertain completeness of pulmonary embolectomy: surgery for pulmonary embolism-how I do it.

Rarely pulmonary embolectomy has also been used as a salvage procedure for acute right ventricle (RV) dysfunction following acute pulmonary embolism (APE). Complete surgical removal of thromboembolus in acute pulmonary thromboembolism is an essential pre-requisite for good outcome. Complete clearance of thromboembolic load from pulmonary arterial tree is difficult to assess intraoperatively. We hereby describe the use of flexible fibre optic bronchoscope (FFB) as angioscope to visualise the pulmonary arterial tree intraoperatively. Angioscopy ascertains the complete clearance up to subsegmental level after thromboembolectomy and aids in the removal of residual thrombus or embolus. Herein, we describe a case series of two patients, where FFB was used as angioscope during surgery for APE.

Present Limitations of Artificial Intelligence in the Emergency Setting - Performance Study of a Commercial, Computer-Aided Detection Algorithm for Pulmonary Embolism.

Since artificial intelligence is transitioning from an experimental stage to clinical implementation, the aim of our study was to evaluate the performance of a commercial, computer-aided detection algorithm of computed tomography pulmonary angiograms regarding the presence of pulmonary embolism in the emergency room. This retrospective study includes all pulmonary computed tomography angiogram studies performed in a large emergency department over a period of 36months that were analyzed by two radiologists experienced in emergency radiology to set a reference standard. Original reports and computer-aided detection results were compared regarding the detection of lobar, segmental, and subsegmental pulmonary embolism. All computer-aided detection findings were analyzed concerning the underlying pathology. False-positive findings were correlated to the contrast-to-noise ratio. Expert reading revealed pulmonary embolism in 182 of 1229 patients (49 % men, 10-97 years) with a total of 504emboli. The computer-aided detection algorithm reported 3331 findings, including 258 (8 %) true-positive findings and 3073 (92 %) false-positive findings. Computer-aided detection analysis showed a sensitivity of 47 % (95 %CI: 33-61 %) on the lobar level and 50 % (95 %CI 43-56 %) on the subsegmental level. On average, there were 2.25 false-positive findings per study (median 2, range 0-25). There was no significant correlation between the number of false-positive findings and the contrast-to-noise ratio (Spearman's Rank Correlation Coefficient = 0.09). Soft tissue (61.0 %) and pulmonary veins (24.1 %) were the most common underlying reasons for false-positive findings. Applied to a population at a large emergency room, the tested commercial computer-aided detection algorithm faced relevant performance challenges that need to be addressed in future development projects. · Computed tomography pulmonary angiograms are frequently acquired in emergency radiology.. · Computer-aided detection algorithms (CADs) can support image analysis.. · CADs face challenges regarding false-positive and false-negative findings.. · Radiologists using CADs need to be aware of these limitations.. · Further software improvements are necessary ahead of implementation in the daily routine.. · Müller-Peltzer K, Kretzschmar L, Negrão de Figueiredo G et al. Present Limitations of Artificial Intelligence in the Emergency Setting - Performance Study of a Commercial, Computer-Aided Detection Algorithm for Pulmonary Embolism. Fortschr Röntgenstr 2021; 193: 1436 - 1444.

НАРУШЕНИЯ МИКРОЦИРКУЛЯЦИИ В ЛЕГКИХ ПО ДАННЫМ ПЕРФУЗИОННОЙ ОФЭКТ У ПАЦИЕНТОВ В ПОСТКОВИДНОМ ПЕРИОДЕ

Сonsidering the influence of the SARS-CoV-2 virus on the pulmonary vascular system, manifested by the development of endotheliitis, vasculitis, thrombosis and coagulopathies, one of the leading directions of radiological examination may be the study of microcirculation by SPECT. Purpose. To assess changes in the microvasculature of the lungs of patients who have undergone COVID infection at different times from the onset of the disease. Material and methods. SPECT data were analyzed in 170 patients with previous coronavirus infection from May 2020 to June 2021 of varying severity. The results of SPECT, MSCT, FVD and coagulation hemostasis (D-dimer, fibrinogen) were compared. Results. All patients were found to have changes in microcirculation in the lungs in the postcoid period. The severity of microcirculation disorders had a significant dependence (p <0.05, r = 0.76) on the degree of damage to the pulmonary parenchyma and an average correlation dependence (r = 0.51) on the timing of the postcoid period. Signs of PE / microthrombosis changes were significantly more frequent (p <0.05, r = 0.82) in patients with a more severe course of the disease. In patients with CLD, microcirculation decreased to critical levels, the overall level of decrease was up to 30% or more compared to the dock period (p = 0.034). The detection of small subsegmental level of triangular microcirculation defects, with partially restored blood flow, correlated to a high degree (r = 0.84) with an increase in the level of fibrinogen (4.6 + 1.8 mg / l) and indicated the consequences of PE, and an increase in the level of D-dimer (1750+ 215 ng / ml) with the presence of a triangular shape of defects in the accumulation of radiopharmaceuticals correlated to a high degree (r = 0.88) with PE. Conclusion. Disorders of microcirculation in the lungs persist for a long time. They are detected in patients, regardless of the severity of the course of the pathological process, they increase during a dynamic study in patients, the deficit of perfusion depends on the degree of damage to the pulmonary parenchyma. The SARS-CoV-2 virus has a detrimental effect on the state of blood circulation in patients with chronic lung diseases. In patients who have undergone COVID-19 with the development of thrombosis, signs of postponed pulmonary embolism are revealed and zones of local pneumosclerosis are formed. © 2021 Russian Electronic Journal of Radiology. All rights reserved.

Feasibility of bronchial wall quantification in low- and ultralow-dose third-generation dual-source CT: An ex vivo lung study.

PurposeTo investigate image quality and bronchial wall quantification in low‐ and ultralow‐dose third‐generation dual‐source computed tomography (CT).MethodsA lung specimen from a formerly healthy male was scanned using third‐generation dual‐source CT at standard‐dose (51 mAs/120 kV, CTDIvol 3.41 mGy), low‐dose (1/4th and 1/10th of standard dose), and ultralow‐dose setting (1/20th). Low kV (70, 80, 90, and Sn100 kV) scanning was applied in each low/ultralow‐dose setting, combined with adaptive mAs to keep a constant dose. Images were reconstructed at advanced modeled iterative reconstruction (ADMIRE) levels 1, 3, and 5 for each scan. Bronchial wall were semi‐automatically measured from the lobar level to subsegmental level. Spearman correlation analysis was performed between bronchial wall quantification (wall thickness and wall area percentage) and protocol settings (dose, kV, and ADMIRE). ANOVA with a post hoc pairwise test was used to compare signal‐to‐noise ratio (SNR), noise and bronchial wall quantification values among standard‐ and low/ultralow‐dose settings, and among ADMIRE levels.ResultsBronchial wall quantification had no correlation with dose level, kV, or ADMIRE level (|correlation coefficients| < 0.3). SNR and noise showed no statistically significant differences at different kV in the same ADMIRE level (1, 3, or 5) and in the same dose group (P > 0.05). Generally, there were no significant differences in bronchial wall quantification among the standard‐ and low/ultralow‐dose settings, and among different ADMIRE levels (P > 0.05).ConclusionThe combined use of low/ultralow‐dose scanning and ADMIRE does not influence bronchial wall quantification compared to standard‐dose CT. This specimen study suggests the potential that an ultralow‐dose scan can be used for bronchial wall quantification.

Balloon-Occluded Trans-Arterial Chemo-Embolization Technique with Repeated Alternate Infusion of Cisplatin Solution and Sparse Gelatin Slurry (RAIB-TACE) for Large Hepatocellular Carcinoma Nodules More than 7 cm in Diameter.

Objective It is sometimes difficult to obtain complete/partial response of large hepatocellular carcinoma (HCC) nodules by trans-arterial chemoembolization/embolization (TACE/TAE). The aim is retrospective investigation of tumor response of large HCC nodules (>7 cm) treated by the new TACE technique, repeated alternate infusion of cisplatin solution, and sparse gelatin slurry under balloon occlusion (RAIB-TACE). Materials and Methods. A microballoon catheter was placed at a proximal portion of the hepatic artery (subsegmental to the lobar level hepatic artery), and alternate infusion of cisplatin solution and sparse gelatin slurry were repeated under balloon occlusion until stasis of gelatin slurry beyond the catheter was seen. RAIB-TACE of multiple proximal hepatic and extrahepatic collateral arteries were performed to treat hemi-lobe or more of the liver while avoiding infusion into gastric and cystic arteries for 19 large nodules (>7 cm) in 19 patients without portal venous invasion. All patients underwent dynamic CT/MRI 1–3 months after RAIB-TACE, and tumor response of each large nodule was evaluated based on modified RECIST criteria. Results CR, PR, SD, and PD were achieved in 11, 8, 0, and 0 nodules, respectively. CR and PR were considered as success, and the ratio of success was 100%. Major complications were abscess formation in the necrotic nodule (n = 1) which was treated by drainage tube placement, and subsegmental level liver infarction (n = 1) which was treated by drainage tube placement, and subsegmental level liver infarction (Conclusion New TACE technique, RAIB-TACE, was useful to achieve successful response of large HCC nodules.

Нарушение кровообращения в легких и развитие хронической дыхательной недостаточности у пациентов с обычной интерстициальной пневмонией

Purpose: To determine the features of circulatory disorders in the lungs in patients with ordinary interstitial pneumonia (OIP) at different stages of the pathological process and with the development of comorbid conditions. &#x0D; Material and methods: The analysis of the results of radiation research methods: computer tomography, computed angiography and single photon emission computed tomography in 64 patients with common interstitial pneumonia. The selection criteria were the presence of respiratory failure and pulmonary hypertension.&#x0D; Results: The combination of interstitial and alveolar changes, their distribution in the lower parts of both lungs with subpleural localization are mainly pathognomonic for IPI. In 85 % of patients with OIP and the formation of a “cellular lung”, local perfusion disorders of various forms, of small size, subsegmental level, located symmetrically in the diaphragm regions were determined. The main distinctive CT signs of adherence to vascular pathology: pulmonary pattern mosaic; subpleural infiltration sites of the lung tissue of heterogeneous structure; defects in filling the pulmonary artery with a contrast agent during CT angiography; triangular subpleurally located areas of perfusion disturbance on SPECT (when SPECT/CT is combined), localized in the area of lung infarction, or in the zone of no changes on CT.&#x0D; Conclusion: The development of pulmonary hypertension and chronic respiratory failure in OIP is determined by several factors that have an active or passive effect on pulmonary hemodynamics. Worsening of the patient’s condition and an increase in the degree of respiratory failure and pulmonary hypertension, contributes to complication of the pulmonary vascular system – pulmonary thromboembolism and (or) thrombosis in situ, as well as persistent infectious inflammatory processes. In the presence of irreversible morphological changes in the lung parenchyma therapeutic measures do not affect the state of microcirculation in the lungs.

POLICY CHANGES AFTER A RARE COMPLICATION OF EBUS-TBNA: EXPECTORATION OF A METAL SHEATH

SESSION TITLE: Wednesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Since the first application of ultrasound in the airway in 1992, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become a widely-used effective and minimally invasive method of diagnosing and staging mediastinal lymph nodes and masses. The procedure is generally well-tolerated. Major complications involving EBUS-TBNA are low, but there are increasing reports of procedure-related complications. We present a case of a retained inner metal sheath of the Olympus EBUS-TNBA needle catheter after instrument malfunction. CASE PRESENTATION: A 47-year old male was referred for EBUS-TBNA for worsening cough for the past year. A computed tomography of the chest revealed bilateral hilar and mediastinal adenopathy concerning for sarcoidosis. Endobronchial ultrasound was used to assist with guiding biopsy of hilar and mediastinal regions. An EBUS-TBNA was performed using an Olympus EBUS-TBNA 22-gauge needle. Specimens were obtained from the 7, 10R, and 11L lymph nodes. During sampling of the left interlobar lymph node, there was unexpected resistance when attempting to advance the needle. The needle was repositioned and the lymph node was aspirated without further difficulty. Rapid On-Site Evaluation revealed non-necrotic granulomatous tissue of the subcarinal lymph node. The tracheobronchial tree was examined to at least the first sub-segmental level. Bronchial mucosa and anatomy were normal with no endobronchial lesions, secretions or foreign bodies visualized. The patient tolerated the procedure well and was discharged. On his way home, the patient reported expectorating “a metal sheath.” The Olympus EBUS-TBNA needle catheter was examined and it was discovered that the inner metal sheath located in the distal plastic sheath of the needle catheter was missing which corresponded to the inner metal sheath of the needle catheter. The patient did not have any complications from this event. DISCUSSION: EBUS-TBNA is the preferred modality in the diagnosis and staging of mediastinal lymph nodes and masses with high specificity and sensitivity. Serious EBUS complication rates range from 0.15-0.16%, including mediastinal abscess, empyema, needle fracture, and hemo-pneumomediastinum, Literature review showed a single case report of an expectorated “stent” from EBUS-TBNA. Due to the malfunction of the needle catheter, a root-cause analysis was performed and protocol changes were subsequently made to our institutional policy. CONCLUSIONS: EBUS-TBNA is accepted as a safe, well-tolerated procedure with low major complication rates. Our case is only the second reported case of assembly malfunction causing unexpected deployment of the inner metal sheath into the bronchi. While no serious complications resulted from this, providers performing EBUS-TBNA need to be aware of this potential device malfunction. We recommend routine inspection of the needle apparatus pre- and post-procedure. Reference #1: Caglayan BYilmaz A, et al. Complications of Convex-Probe Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration: A Multi-Center Retrospective Study. Respir Care. 2016 Feb;61(2):243-8. Reference #2: Zamora FD, Moughrabieh A, et al. An Expectorated "Stent": An Unexpected Complication of EBUS-TBNA. J Bronchology Interv Pulmonol. 2017 Jul;24(3):250-252. Reference #3: Asano F, Aoe M, Ohsaki Y, et al. Complications associated with endobronchial ultrasound-guided transbronchial needle aspiration: a nationwide survey by the Japan Society for Respiratory Endoscopy. Respir Res. 2013;14:50 DISCLOSURES: No relevant relationships by Michael Ayers, source=Web Response No relevant relationships by Ngoc-Tram Ha, source=Web Response No relevant relationships by Cynthia Tsai, source=Web Response

The organisation and structure of rhotics in American English rhymes

Language-specific maximal size restrictions on syllables have been defined using frames such as moraic structure. In General American English, a trimoraic syllable template makes largely successful predictions about contexts where tense/lax vowel contrasts are neutralised, but neutralisation preceding a coda rhotic has not been adequately explained. We attribute the apparent special properties of coda /ɹ/ to two characteristics of its representation, informed by our articulatory investigation: sequential coordination of dorsal and coronal subsegmental units and a high blending strength specification, corresponding to high coarticulatory dominance. Characteristics of coda laterals are compared. Our approach employs phonological representations where sequencing is encoded directly among subsegments, and coordination is sensitive to strength. Mora assignment is computed over sequencing of subsegments, predicting that complex segments may be bimoraic. The account brings phonotactics for rhymes with postvocalic liquids into line with the trimoraic template, and supports representing coordination and strength at the subsegmental level.

High-resolution lung MRI with Ultrashort-TE: 1.5 or 3 Tesla?

PurposeTo assess the influence of magnetic field strength and additionally of acquisition and reconstruction parameters on the quality of high-resolution lung MRI, using a prototype Ultrashort-TE (UTE) sequence. Materials and methodsThis prospective study received ethical approval and all participants provided written informed consent. From January to February 2018, images were obtained in 10 healthy volunteers at 1.5 T and 3 T with a prototypical free-breathing UTE spiral 3D-GRE sequence with volumetric interpolation (VIBE) sequence and near-millimeter resolution. Five sequences were acquired to assess the effects of magnetic field strength (1.5 vs 3 T), voxel resolution (1.2 vs 1.0mm3), number of spiral interleaves (464 vs 264) and iterative reconstruction (iterative self-consistent parallel imaging reconstruction [SPIRiT] versus Non-Uniform Fourier Transform [NUFFT]) on image quality. Image quality was assessed by two independent observers. They evaluated the proportion of detected airways from the trachea down to the subsegmental level and placed ROI in the lung parenchyma, airways and vessels to calculate signal-to noise (SNR) and contrast-to-noise (CNR) ratios. Continuous variables were expressed as mean ± standard deviation and were compared by t-test. ResultsNearly complete visualization of the segmental bronchi (94 ± 12 to 99 ± 3%) was obtained with all sequences. Acquisition at 3 T (p < 0.001), use of a fewer spiral interleaves (p < 0.001) and NUFFT reconstruction (p < 0.001) all resulted in a significantly lower visibility of the subsegmental bronchi, while a smaller voxel size improved their visibility (p = 0.001). SNR and CNR were significantly lower at 3 T (140.2 ± 19.9 vs 190.2 ± 34.8, p < 0.001; and 5.7 ± 2.4vs 10.8 ± 2.8, p < 0.001, respectively). ConclusionsUsing equivalent acquisition and reconstruction parameters, image quality was lower at 3 T than at 1.5 T with decreased visibility of the subsegmental bronchi and lower SNR and CNR values.

Overdiagnosis of pulmonary embolism: definition, causes and implications.

Overuse of computed tomography pulmonary angiography to diagnose pulmonary embolism in people who have only a low pre-test probability of pulmonary embolism has received significant attention in the past. The issue of overdiagnosis of pulmonary embolism, a potential consequence of overtesting, has been less explored. The term “overdiagnosis”, used in a narrow sense, describes a correct (true positive) diagnosis in a person but without any associated harm. The aim of this review is to summarise literature on the topic of overdiagnosis of pulmonary embolism and translate this epidemiological concept into the clinical practice of respiratory professionals. The review concludes that the location of pulmonary embolism at a subsegmental level, rather than whether a diagnosis was made incidentally or following an investigation for suspected pulmonary embolism, is the best predictor for situations in which anticoagulation may not be necessary. In the absence of strong evidence of the optimal management of subsegmental pulmonary embolism, treatment decisions should be made case by case, taking into account the patient's situation and preference.Key pointsSince the introduction of computed tomography pulmonary angiography in 1998, there has been a steep increase in the diagnosis of pulmonary embolism (PE).An increased incidence of PE diagnoses, but an almost stable mortality from PE in the population, together with a decreased case fatality, point towards overdiagnosis (in the absence of more effective treatment).Whether PE is diagnosed as an incidental finding or following an investigation for suspected PE does not appear to influence the need for anticoagulation therapy.An isolated subsegmental PE may not require anticoagulation therapy, and treatment decisions should be made case by case, taking into account the patient's situation and preference.A suggested definition of overdiagnosis of PE: a diagnosis of PE that, if left untreated, would not lead to more harm than if it were treated with anticoagulation therapy, independent of symptoms.Educational aimsTo understand the term “overdiagnosis” based on its narrow definition and be able to apply it to PE.To outline the diagnostic approach to PE.To summarise what is known about the treatment of incidentally detected PE.To summarise what is known about the treatment of subsegmental PE.To understand in which situations anticoagulation therapy for PE may not be beneficial.

End-to-end acoustic modeling using convolutional neural networks for HMM-based automatic speech recognition

In hidden Markov model (HMM) based automatic speech recognition (ASR) system, modeling the statistical relationship between the acoustic speech signal and the HMM states that represent linguistically motivated subword units such as phonemes is a crucial step. This is typically achieved by first extracting acoustic features from the speech signal based on prior knowledge such as, speech perception or/and speech production knowledge, and, then training a classifier such as artificial neural networks (ANN), Gaussian mixture model that estimates the emission probabilities of the HMM states. This paper investigates an end-to-end acoustic modeling approach using convolutional neural networks (CNNs), where the CNN takes as input raw speech signal and estimates the HMM states class conditional probabilities at the output. Alternately, as opposed to a divide and conquer strategy (i.e., separating feature extraction and statistical modeling steps), in the proposed acoustic modeling approach the relevant features and the classifier are jointly learned from the raw speech signal. Through ASR studies and analyses on multiple languages and multiple tasks, we show that: (a) the proposed approach yields consistently a better system with fewer parameters when compared to the conventional approach of cepstral feature extraction followed by ANN training, (b) unlike conventional method of speech processing, in the proposed approach the relevant feature representations are learned by first processing the input raw speech at the sub-segmental level ( ≈ 2 ms). Specifically, through an analysis we show that the filters in the first convolution layer automatically learn “in-parts” formant-like information present in the sub-segmental speech, and (c) the intermediate feature representations obtained by subsequent filtering of the first convolution layer output are more discriminative compared to standard cepstral features and could be transferred across languages and domains.