Alveolar crystal burden in stone workers with artificial stone silicosis.

BACKGROUND AND OBJECTIVE: An epidemic of silicosis has emerged due to a failure to control risks associated with exposure to high-silica content respirable dust generated while working with artificial stone products. Methods for quantification of alveolar crystal burden are needed to advance our understanding of the pathobiology of silica-related lung injury as well as assisting in the diagnosis, clinical management and prognostication of affected workers. The objective of this study was to develop and validate novel methods to quantify alveolar crystal burden in bronchoalveolar lavage (BAL) fluid from patients with artificial stone silicosis. METHODS: New methods to quantify and analyse alveolar crystal in BAL from patients with artificial stone silicosis were developed. Crystals were isolated and counted by microscopy and alveolar crystal burden was calculated using a standard curve generated by titration of respirable α-Quartz. The utility of the assay was then assessed in 23 patients with artificial stone silicosis. RESULTS: Alveolar crystal burden was greater in patients with silicosis (0.44 picograms [pg]/cell [0.08-3.49]) compared to patients with other respiratory diagnoses (0.057 pg/cell [0.01-0.34]; p < 0.001). Alveolar crystal burden was positively correlated with years of silica exposure (ρ = 0.49, p = 0.02) and with decline in diffusing capacity of the lungs for carbon monoxide (ρ = -0.50, p = 0.02). CONCLUSION: Alveolar crystal burden quantification differentiates patients with silicosis from patients with other respiratory disorders. Furthermore, crystal burden is correlated with the rate of decline in lung function in patients with artificial stone silicosis.

Comparison of objective criteria and expert visual interpretation to classify benign and malignant hilar and mediastinal nodes on 18-F FDG PET/CT.

BACKGROUND AND OBJECTIVE: There is widespread adoption of FDG-PET/CT in staging of lung cancer, but no universally accepted criteria for classifying thoracic nodes as malignant. Previous studies show high negative predictive values, but reporting criteria and positive predictive values varies. Using Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) results as gold standard, we evaluated objective FDG-PET/CT criteria for interpreting mediastinal and hilar nodes and compared this to expert visual interpretation (EVI). METHODS: A retrospective review of all patients with lung cancer who had both FDG-PET/CT and EBUS-TBNA from 2008 to 2010 was performed. Scan interpretation was blinded to histology. Patients from 2008/2009 were used for the prediction set. The validation set analysed patients from 2010. Objective FDG-PET/CT criteria were SUVmax lymph node (SUVmaxLN), ratio SUVmaxLN/SUVmax primary lung malignancy, ratio SUVmaxLN/SUVaverage liver, ratio SUVmaxLN/SUVmax liver and ratio SUVmaxLN/SUVmax blood pool. A nuclear medicine physician reviewed all scans and classified nodal stations as benign or malignant. RESULTS: Eighty-seven malignant lymph nodes and 41 benign nodes were in the prediction set. All objective FDG-PET/CT criteria analysed were significantly higher in the malignant group (P < 0.0001). EVI correctly classified 122/128 nodes (95.3%). Thirty-four malignant nodes and 19 benign nodes were in the validation set. The new proposed cut-off values of the objective criteria from the prediction set correctly classified 44/53 (83.0%) nodes: 28/34 (82.4%) malignant nodes and 16/19 (84.2%) benign nodes. EVI had 91% accuracy: 33/34 (97.1%) malignant nodes and 15/19 (79.0%) benign nodes. CONCLUSIONS: Objective analysis of 18-F FDG PET/CT can differentiate between malignant and benign nodes but is not superior to EVI.

Grey scale texture analysis of endobronchial ultrasound mini probe images for prediction of benign or malignant aetiology.

BACKGROUND AND OBJECTIVE: Expert analysis of endobronchial ultrasound mini probe (EBUS-MP) images has established subjective criteria for discriminating benign and malignant disease. Minimal data are available for objective analysis of these images. The aim of this study was to determine if greyscale texture analysis could differentiate between benign and malignant lung lesions. METHODS: Digital EBUS-MP images with a gain setting of 10/19 and contrast setting of 4/8 from 2007 until 2012 inclusive were included. These images had an expert-defined region of interest (ROI) mapped. ROI were analysed for the following greyscale texture features: mean pixel value, difference between maximum and minimum pixel value, standard deviation of the mean pixel value, entropy, correlation, energy and homogeneity. Significant greyscale texture features differentiating benign from malignant disease were used by two physicians to assess a validation set. RESULTS: A total of 167 images were available. The first 85 lesions were used in the prediction set. Benign lesions had larger differences between maximum and minimum pixel values, larger standard deviations of the mean pixel values and higher entropy than malignant lesions (P < 0.0001 for all values). A total of 82 peripheral lesions were in the validation set. Physician 1 correctly classified 63/82 (76.8%) with a negative predictive value (NPV) for malignancy of 82% and positive predictive value (PPV) of 75%. Physician 2 correctly classified 62/82 (75.6%) with a NPV of 100% and PPV of 71.0%. CONCLUSIONS: Greyscale texture analysis of EBUS-MP images can help establish aetiology with a high NPV for malignancy.

Comparing Polymerase Chain Reaction Testing of Nasopharyngeal Swab and Lower Respiratory Tract Specimens for the Diagnosis of Pneumocystis jirovecii Pneumonia.

Using nasopharyngeal (NP) swab samples instead of lower respiratory tract specimens for polymerase chain reaction (PCR) to diagnose Pneumocystis jirovecii pneumonia (PJP) may be better tolerated and improve diagnostic accessibility. In this 2-year Australian retrospective cohort study of patients with clinically suspected PJP, P jirovecii PCR on NP swab samples had perfect specificity but low sensitivity (0.66).

Rapid cytological analysis of endobronchial ultrasound-guided aspirates in sarcoidosis.

Rapid on-site evaluation (ROSE) of endobronchial ultrasound-guided transbronchial needle aspirates (EBUS-TBNA) has not been compared to final detailed cytological analysis in patients with suspected sarcoidosis. To assess the diagnostic accuracy of EBUS-TBNA with ROSE in patients with suspected sarcoidosis, a prospective two-centre study performed EBUS-TBNA with ROSE of cellular material followed by transbronchial lung biopsy (TBLB) and endobronchial biopsy (EBB). The diagnostic accuracy of EBUS-TBNA with ROSE was compared to the final cytological assessment and to TBLB and EBB. Analysis confirmed 49 out of 60 cases of sarcoidosis. ROSE sensitivity was 87.8% (specificity 91%, positive predictive value 97.7%). ROSE slide interpretation in combination with the final fixed slide and cell block preparations had a sensitivity of 91.8% (specificity 100%, positive predictive value 100%). 67% of patients were confirmed as having sarcoidosis on TBLB and 29% on EBB. Interobserver agreement between cytotechnologists and pathologists was very good (κ=0.91, 95% CI 0.80-1.0 and κ=0.91, 95% CI 0.79-1.0, respectively). EBUS-TBNA with ROSE has high diagnostic accuracy and interobserver agreement and informs the bronchoscopist in theatre whether additional diagnostic procedures need to be undertaken. EBUS-TBNA with ROSE should therefore be considered as the first-line investigation of sarcoidosis.

A randomised study of comfort during bronchoscopy comparing conscious sedation and anaesthetist-controlled general anaesthesia, including the utility of bispectral index monitoring.

BACKGROUND: The difference in patient comfort with conscious sedation versus general anaesthesia for bronchoscopy has not been adequately assessed in a randomised trial. This study aimed to assess if patient comfort during bronchoscopy with conscious sedation is noninferior to general anaesthesia. METHODS: 96 subjects were randomised to receive conscious sedation or general anaesthesia for bronchoscopy. The primary outcome was subject comfort. Secondary outcomes included willingness to undergo a repeat procedure if necessary and level of sedation assessed clinically and by bispectral index (BIS) monitoring. RESULTS: There was no significant difference between subject comfort scores (difference -0.01, 95% CI -0.63-0.61 on a 10-point scale; p=0.97) or willingness to undergo a repeat procedure (97.7% versus 91.8%, 95% CI -4.8-15.5%; p=0.37). Deeper levels of sedation in the general anaesthesia cohort was confirmed with both clinical and BIS monitoring. There was no significant difference in diagnostic accuracy (conscious sedation 93.9%, 95% CI 80.4-98.3% versus general anaesthesia 86.5%, 95% CI 72.0-94.1%; p=0.43). There were more complications (29.6%, 95% CI 18.2-44.2% versus 6.1%, 95% CI 2.1-16.5%; p<0.01) in the general anaesthesia group. There was no relationship between high BIS scores and subject discomfort. BIS levels <40 during a procedure were associated with increased complications. CONCLUSION: Conscious sedation is not inferior to general anaesthesia in providing patient comfort during bronchoscopy, despite lighter sedation, and is associated with fewer complications and comparable diagnostic accuracy. BIS monitoring may have a role in preventing complications associated with deeper sedation.

Optical differentiation between malignant and benign lymphadenopathy by grey scale texture analysis of endobronchial ultrasound convex probe images.

BACKGROUND: Morphologic and sonographic features of endobronchial ultrasound (EBUS) convex probe images are helpful in predicting metastatic lymph nodes. Grey scale texture analysis is a well-established methodology that has been applied to ultrasound images in other fields of medicine. The aim of this study was to determine if this methodology could differentiate between benign and malignant lymphadenopathy of EBUS images. METHODS: Lymph nodes from digital images of EBUS procedures were manually mapped to obtain a region of interest and were analyzed in a prediction set. The regions of interest were analyzed for the following grey scale texture features in MATLAB (version 7.8.0.347 [R2009a]): mean pixel value, difference between maximal and minimal pixel value, SEM pixel value, entropy, correlation, energy, and homogeneity. Significant grey scale texture features were used to assess a validation set compared with fluoro-D-glucose (FDG)-PET-CT scan findings where available. RESULTS: Fifty-two malignant nodes and 48 benign nodes were in the prediction set. Malignant nodes had a greater difference in the maximal and minimal pixel values, SEM pixel value, entropy, and correlation, and a lower energy (P < .0001 for all values). Fifty-one lymph nodes were in the validation set; 44 of 51 (86.3%) were classified correctly. Eighteen of these lymph nodes also had FDG-PET-CT scan assessment, which correctly classified 14 of 18 nodes (77.8%), compared with grey scale texture analysis, which correctly classified 16 of 18 nodes (88.9%). CONCLUSIONS: Grey scale texture analysis of EBUS convex probe images can be used to differentiate malignant and benign lymphadenopathy. Preliminary results are comparable to FDG-PET-CT scan.