Total Interstitial Lung Disease Research Articles

Value of CT quantification in progressive fibrosing interstitial lung disease: a deep learning approach.

To evaluate the relationship of changes in the deep learning-based CT quantification of interstitial lung disease (ILD) with changes in forced vital capacity (FVC) and visual assessments of ILD progression, and to investigate their prognostic implications. This study included ILD patients with CT scans at intervals of over 2 years between January 2015 and June 2021. Deep learning-based texture analysis software was used to segment ILD findings on CT images (fibrosis: reticular opacity + honeycombing cysts; total ILD extent: ground-glass opacity + fibrosis). Patients were grouped according to the absolute decline of predicted FVC (< 5%, 5-10%, and ≥ 10%) and ILD progression assessed by thoracic radiologists, and their quantification results were compared among these groups. The associations between quantification results and survival were evaluated using multivariable Cox regression analysis. In total, 468 patients (239 men; 64 ± 9.5 years) were included. Fibrosis and total ILD extents more increased in patients with larger FVC decline (p < .001 in both). Patients with ILD progression had higher fibrosis and total ILD extent increases than those without ILD progression (p < .001 in both). Increases in fibrosis and total ILD extent were significant prognostic factors when adjusted for absolute FVC declines of ≥ 5% (hazard ratio [HR] 1.844, p = .01 for fibrosis; HR 2.484, p < .001 for total ILD extent) and ≥ 10% (HR 2.918, p < .001 for fibrosis; HR 3.125, p < .001 for total ILD extent). Changes in ILD CT quantification correlated with changes in FVC and visual assessment of ILD progression, and they were independent prognostic factors in ILD patients. Quantifying the CT features of interstitial lung disease using deep learning techniques could play a key role in defining and predicting the prognosis of progressive fibrosing interstitial lung disease. • Radiologic findings on high-resolution CT are important in diagnosing progressive fibrosing interstitial lung disease. • Deep learning-based quantification results for fibrosis and total interstitial lung disease extents correlated with the decline in forced vital capacity and visual assessments of interstitial lung disease progression, and emerged as independent prognostic factors. • Deep learning-based interstitial lung disease CT quantification can play a key role in diagnosing and prognosticating progressive fibrosing interstitial lung disease.

Photon-counting computed tomography in the assessment of rheumatoid arthritis-associated interstitial lung disease: an initial experience

Interstitial lung disease (ILD) accounts for a significant proportion of mortality and morbidity in patients with rheumatoid arthritis (RA). The aim of this cross-sectional study is to evaluate the performance of novel photon-counting detector computed tomography (PCD-CT) in the detection of pulmonary parenchymal involvement. Sixty-one patients with RA without a previous definitive diagnosis of ILD underwent high-resolution (HR) (0.4 mm slice thickness) and ultra-high-resolution (UHR) (0.2 mm slice thickness) PCDCT examination. The extent of interstitial abnormalities [ground-glass opacity (GGO), reticulation, bronchiectasis, and honeycombing] were scored in each lobe using a Likert-type scale. Total ILD scores were calculated as the sum of scores from all lobes. Reticulation and bronchiectasis scores were higher in the UHR measurements taken compared with the HR protocol [median (quartile 1, quartile 3): 2 (0, 3.5) vs. 0 (0, 3), P < 0.001 and 2 (0, 2) vs. 0 (0, 2), P < 0.001, respectively]; however, GGO and honeycombing scores did not differ [2 (2, 4) vs. 2 (2, 4), P = 0.944 and 0 (0, 0) vs. 0 (0, 0), P = 0.641, respectively]. Total ILD scores from both HR and UHR scans showed a mild negative correlation in diffusion capacity for carbon monoxide (HR: r = -0.297, P = 0.034; UHR: r = -0.294, P = 0.036). The pattern of lung parenchymal involvement did not differ significantly between the two protocols. The HR protocol had significantly lower volume CT dose index [0.67 (0.69, 1.06) mGy], total dose length product [29 (24.48, 33.2) mGy*cm] compared with UHR scans [8.18 (6.80, 9.23) mGy, P < 0.001 and 250 (218, 305) mGy*cm, P < 0.001]. UHR PCD-CT provides more detailed information on ILD in patients with RA than low-dose HR PCDCT. HR PCD-CT image acquisition with a low effective radiation dose may serve as a valuable, low-radiation screening tool in the selection of patients for further, higher-dose UHR PCD-CT screening.

Lung vascular changes as biomarkers of severity in systemic sclerosis-associated interstitial lung disease.

It has recently become possible to assess lung vascular and parenchymal changes quantitatively in thoracic CT images using automated software tools. We investigated the vessel parameters of patients with SSc, quantified by CT imaging, and correlated them with interstitial lung disease (ILD) features. SSc patients undergoing standard of care pulmonary function testing and CT evaluation were retrospectively evaluated. CT images were analysed for ILD patterns and total pulmonary vascular volume (PVV) extents with Imbio lung texture analysis. Vascular analysis (volumes, numbers and densities of vessels, separating arteries and veins) was performed with an in-house developed software. A threshold of 5% ILD extent was chosen to define the presence of ILD, and commonly used cut-offs of lung function were adopted. A total of 79 patients [52 women, 40 ILD, mean age 56.2 (s.d. 14.2) years, total ILD extent 9.5 (10.7)%, PVV/lung volume % 2.8%] were enrolled. Vascular parameters for total and separated PVV significantly correlated with functional parameters and ILD pattern extents. SSc-associated ILD (SSc-ILD) patients presented with an increased number and volume of arterial vessels, in particular those between 2 and 4 mm of diameter, and with a higher density of arteries and veins of <6 mm in diameter. Considering radiological and functional criteria concomitantly, as well as the descriptive trends from the longitudinal evaluations, the normalized PVVs, vessel numbers and densities increased progressively with the increase/worsening of ILD extent and functional impairment. In SSc patients CT vessel parameters increase in parallel with ILD extent and functional impairment, and may represent a biomarker of SSc-ILD severity.

Deep Learning-based Outcome Prediction in Progressive Fibrotic Lung Disease Using High-Resolution Computed Tomography.

Rationale: Reliable outcome prediction in patients with fibrotic lung disease using baseline high-resolution computed tomography (HRCT) data remains challenging. Objectives: To evaluate the prognostic accuracy of a deep learning algorithm (SOFIA [Systematic Objective Fibrotic Imaging Analysis Algorithm]), trained and validated in the identification of usual interstitial pneumonia (UIP)-like features on HRCT (UIP probability), in a large cohort of well-characterized patients with progressive fibrotic lung disease drawn from a national registry. Methods: SOFIA and radiologist UIP probabilities were converted to Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED)-based UIP probability categories (UIP not included in the differential, 0-4%; low probability of UIP, 5-29%; intermediate probability of UIP, 30-69%; high probability of UIP, 70-94%; and pathognomonic for UIP, 95-100%), and their prognostic utility was assessed using Cox proportional hazards modeling. Measurements and Main Results: In multivariable analysis adjusting for age, sex, guideline-based radiologic diagnosis, anddisease severity (using total interstitial lung disease [ILD] extent on HRCT, percent predicted FVC, DlCO, or the composite physiologic index), only SOFIA UIP probability PIOPED categories predicted survival. SOFIA-PIOPED UIP probability categories remained prognostically significant in patients considered indeterminate (n = 83) by expert radiologist consensus (hazard ratio, 1.73; P < 0.0001; 95% confidence interval, 1.40-2.14). In patients undergoing surgical lung biopsy (n = 86), after adjusting for guideline-based histologic pattern and total ILD extent on HRCT, only SOFIA-PIOPED probabilities were predictive of mortality (hazard ratio, 1.75; P < 0.0001; 95% confidence interval, 1.37-2.25). Conclusions: Deep learning-based UIP probability on HRCT provides enhanced outcome prediction in patients with progressive fibrotic lung disease when compared with expert radiologist evaluation or guideline-based histologic pattern. In principle, this tool may be useful in multidisciplinary characterization of fibrotic lung disease. The utility of this technology as a decision support system when ILD expertise is unavailable requires further investigation.

The Prevalence of Pulmonary Embolism in Patients With Interstitial Lung Disease: A Cross-Sectional Retrospective Study.

Objective: Interstitial lung disease (ILD) can be complicated by comorbidities, particularly pulmonary embolism (PE). We aimed to assess the prevalence of PE in ILD patients.Methods: Our study is a cross-sectional retrospective study conducted on ILD cases diagnosed between January 1, 2010, and June 30, 2021. Out of the total ILD cases (n = 153), we enrolled for analysis only those who underwent a computed tomography pulmonary angiography (CTPA) (n = 48). We recorded the number of patients who had a PE event on CTPA, gender, age at PE and ILD diagnoses, a chronology of PE with ILD diagnosis, PE characteristics, PE therapy, type of ILD, radiographic progression of ILD, presence of pulmonary hypertension, and mortality.Results: Seven patients out of 48, had PE (14.6%). The mean age at the time of PE diagnosis was 70 ± 9.73 years. No statistical difference existed between the PE and non-PE groups regarding gender predominance or the age at ILD diagnosis. All of the identified PE events (n = 7) were segmental (100%), one was saddle PE (14.3%) and one was recurrent (14.3%). No PE events were diagnosed prior to ILD diagnosis, three patients (42.9%) had a simultaneous diagnosis of PE and ILD, and four patients (57.1%) were diagnosed with a PE after ILD diagnosis by a mean time of eight months. No difference in ILD radiographic progression, pulmonary hypertension, or mortality between the two groups was found.Conclusion: PE is not uncommon in ILD and needs to be ruled out, especially in patients with worsening respiratory status.

Chest wall muscle atrophy as a contributory factor for forced vital capacity decline in systemic sclerosis-associated interstitial lung disease.

To investigate the potential contribution of accessory respiratory muscle atrophy to the decline of forced vital capacity (FVC) in patients with SSc-associated interstitial lung disease (ILD). This single-centre, retrospective study enrolled 36 patients with SSc-ILD who underwent serial pulmonary function tests and chest high-resolution CT (HRCT) simultaneously at an interval of 1-3 years. The total extent of ILD and chest wall muscle area at the level of the ninth thoracic vertebra on CT images were evaluated by two independent evaluators blinded to the patient information. Changes in the FVC, ILD extent, and chest wall muscle area between the two measurements were assessed in terms of their correlations. Multiple regression analysis was conducted to identify the independent contributors to FVC decline. Interval changes in FVC and total ILD extent were variable among patients, whereas chest wall muscle area decreased significantly with time (P=0.0008). The FVC change was negatively correlated with the change in ILD extent (r=-0.48, P=0.003) and was positively correlated with the change in the chest wall muscle area (r = 0.53, P=0.001). Multivariate analysis revealed that changes in total ILD extent and chest wall muscle area were independent contributors to FVC decline. In patients with SSc-ILD, FVC decline is attributable not only to the progression of ILD but also to the atrophy of accessory respiratory muscles. Our findings call attention to the interpretation of FVC changes in patients with SSc-ILD.

Clinical Research on Prognostic Evaluation of Subjects With IPF by Peripheral Blood Biomarkers, Quantitative Imaging Characteristics and Pulmonary Function Parameters

IntroductionIdiopathic pulmonary fibrosis (IPF) is an irreversible and progressive fatal interstitial lung disease with a poor prognosis. The aim of this study is to investigate the predictive value of combined blood biomarkers, pulmonary function and quantitative monitoring by computer-aided diagnosis (CAD) system in IPF patients. MethodsPulmonary baseline function and pathological features of 126 patients with IPF were analyzed using spirometry and chest X-ray. Patients were divided into survival group and non-survival group after 5 years follow-up. The relationships the levels of peripheral blood biomarkers, quantitative imaging characteristics and pulmonary function were analyzed between the two groups. ResultsThe baseline level of serum Krebs von den Lungen-6 (KL-6) and C-X-C motif chemokine 13 (CXCL13) were moderately or highly correlated with annual changes in forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO), total lung capacity (TLC), total interstitial lung disease (ILD) lesions, and the volume changes of reticular. The baseline level of serum KL-6 was higher than the cut-off value of 800.0U/ml and baseline level of serum CXCL13 was higher than the cut-off value of 62.0pg/ml. IPF patients with baseline levels of serum KL-6 and CXCL13 lower than the cut-off value had longer median survival time. ConclusionsSerum KL-6 and CXCL13 may be predictive biomarkers for the outcomes of patients with IPF patients and their baseline levels were related to the progression of pulmonary function and quantitative monitoring by CAD system.

SAT0553 QUANTITATIVE ANALYSIS OF IMAGING FEATURES AT CHEST CT OF PULMONARY ARTERIAL AND VENOUS COMPONENTS IN SYSTEMIC SCLEROSIS-INTERSTITIAL LUNG DISEASE (SSc-ILD).

Background:Interstitial lung disease (ILD) and pulmonary arterial hypertension carry a negative impact on SSc prognosis. Chest CT is the gold standard in assessing ILD and helps in evaluating associated vascular involvement.Objectives:As qualitative analysis of CT scans is limited by low reproducibility and time constraints, we aimed at evaluating parenchymal and vascular features in SSc-ILD by quantitative analysis (QA) of CT scans and testing the relationship with clinical-functional data.Methods:We prospectively enrolled 80 patients who underwent PFTs and chest CT scan spirometry gated at TLC on the same day. Clinical, lung functional and diffusion data, as well as disability indexes were collected. CT images were analyzed by a computational platform for texture analysis of ILD patterns (CALIPER), through Imbio LTA. It quantified the extent of normal pattern (NP %), ground glass opacities (GG %), reticulation (RET %), honeycombing (HC %), total ILD extent (ILD EXT %) and hyperlucent (HL %). Low density areas, representing emphysematous area, were also quantified (LDA %). For lung vessel analysis, a software program developed by the Ludwig Boltzmann Institute for Lung Vascular Research was used. This software determined total, arterial, and venous vascular volumes (TV, AV, VV), and relative volumes (TV%, AV%, VV%), as well as density and number for total, arterial and venous vessels.Results:43/80 patients/CT scans were eligible for both software analyses, while 36/43 for arterial and venous separation. TV% and total vessel density were correlated positively with mRSS and negatively with %FVC (r=-0.537 and r=-0.382) and %TLC (r=-0.511 and r=-0.648), while vessel tortuosity correlated positively with %DLco. This was confirmed when separately analyzing arterial vessels, while VV% negatively correlated with %FVC, %TLC and %DLco. There was a positive correlation between %ILD patterns and %vascular volumes, being significant for TV%-AV%, total vessels and arterial density. Conversely, %ILD patterns were negatively correlated with VV and number of veins detected, despite positive correlation between VV% and ILD_EXT%. When clustering patients according to %FVC and %DLco with 80% normal cutoff, %FVC allowed clustering according to significantly different ILD patterns extents and vascular features, while %DLCO for vascular features only. Moreover, the consecutive addition of functional impairment and worsening of ILD (from both normal %FVC and %Dlco, to %DLco impairment only to both %FVC and %Dlco impairment), there was a significant increase in %TV, % AV and %VV, with the exception of decrease in %VV and venous density in patients with double impairment versus DLco single impairment.Conclusion:This is the first study showing in SSc a direct correlation between ILD and the increase in lung vascular volume, which is characterized by increase in arterial volume and density and reduction in venous volume and number. These results might be explained by the reduction of pulmonary volume due to fibrosis. However, also a para-physiological mechanism of redistribution of blood flow in lung areas, less involved by ILD, might be considered. Further studies on lung vessel quantification and distribution are ongoing.Disclosure of Interests:Cosimo Bruni Speakers bureau: Actelion, Eli Lilly, Mariaelena Occhipinti Consultant of: Imbio, Gianna Camiciottoli: None declared, Maurizio Bartolucci: None declared, Michael Pienn: None declared, Gemma Lepri: None declared, Alessio Fabbrizzi: None declared, Alessandra Tottoli: None declared, Giuglia Ciardi: None declared, Dilia Giuggioli: None declared, Giovanna CUOMO: None declared, Francesco Masini: None declared, Horst Olschewski: None declared, Federico Lavorini: None declared, Linda Calistri: None declared, Marco Matucci-Cerinic Grant/research support from: Actelion, MSD, Bristol-Myers Squibb, Speakers bureau: Acetelion, Lilly, Boehringer Ingelheim

THU0153 TCZ MIGHT BE A RISK FACTOR FOR WORSENING OF ILD, PARTICULARLY OF CHRONIC ILD

Background:Interstitial lung disease (ILD), frequent lung involvement, determine the prognosis of patients with RA. The presence of ILD also influences the selection of RA therapy. However, it is not fully elucidated what groups of RA-ILD patients worsen ILD.Objectives:To identify the risk factors for worsening of ILD in RA patients under biological DMARD (bDAMARDs) therapy; particularly to determine whether types of bDMARDs are associated with exacerbation of ILD.Methods:A retrospective cohort study was conducted. Subjects were consecutive 91 RA-ILD patients who received HR-CT examination at starting and during bDMARDs therapy. Clinical data were collected by reviewing.ILD was diagnosed, when patients showed ground-glass opacity (GGO), consolidation, reticular pattern or honeycomb; the former two were acute and the latter two were chronic ILD lesions. The extent of each lesion was scored and recorded. When the score was increased, the lesion was judged as worsened. The incidence of exacerbation of ILD under an indicated agent was calculated as follows; the sum of (exposure period of the agent/exposure period of any agent) in patients with the exacerbation was divided by total exposure period of the agent.Results:Subjects were 36 males and 55 females with a mean age of 66.8 years. At the entry, GGO, consolidation, reticular and honeycomb were found in16, 20, 63 and 17, respectively. Acute and chronic ILD were observed in 34 and 68, respectively. ILD worsened in 35 (38.5%). Between patients with and without ILD exacerbation, no differences were found in demographics (sex, age, disease duration, the positivity for anti-CCP ab and RF) and radiographic findings of pulmonary abnormalities. Disease activities at as 1st and sequential CT examinations were similar in both groups.The incidences of the worsening of ILD varied according to bDMARDs (Fig 1). The incidence of total ILD worsening was high in TCZ compared to TNF and ABT. The incidence of acute ILD worsening was similar among the three groups. However, the worsening of chronic ILD was more frequently found in TCZ than other bDMARDs. The incidence of death by respiratory failure was similar in TNF, ABT, and TCZ (Fig. 2).Fig. 1Conclusion:TCZ might be a risk factor for exacerbation of ILD, particularly of chronic ILD.Fig. 2Disclosure of Interests:None declared

Clinical Research on Prognostic Evaluation of Subjects With IPF by Peripheral Blood Biomarkers, Quantitative Imaging Characteristics and Pulmonary Function Parameters

IntroductionIdiopathic pulmonary fibrosis (IPF) is an irreversible and progressive fatal interstitial lung disease with a poor prognosis. The aim of this study is to investigate the predictive value of combined blood biomarkers, pulmonary function and quantitative monitoring by computer-aided diagnosis (CAD) system in IPF patients. MethodsPulmonary baseline function and pathological features of 126 patients with IPF were analyzed using spirometry and chest X-ray. Patients were divided into survival group and non-survival group after 5 years follow-up. The relationships the levels of peripheral blood biomarkers, quantitative imaging characteristics and pulmonary function were analyzed between the two groups. ResultsThe baseline level of serum Krebs von den Lungen-6 (KL-6) and C-X-C motif chemokine 13 (CXCL13) were moderately or highly correlated with annual changes in forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO), total lung capacity (TLC), total interstitial lung disease (ILD) lesions, and the volume changes of reticular. The baseline level of serum KL-6 was higher than the cut-off value of 800.0U/ml and baseline level of serum CXCL13 was higher than the cut-off value of 62.0pg/ml. IPF patients with baseline levels of serum KL-6 and CXCL13 lower than the cut-off value had longer median survival time. ConclusionsSerum KL-6 and CXCL13 may be predictive biomarkers for the outcomes of patients with IPF patients and their baseline levels were related to the progression of pulmonary function and quantitative monitoring by CAD system.

Chronic hypersensitivity pneumonitis: identification of key prognostic determinants using automated CT analysis

BackgroundChronic hypersensitivity pneumonitis (CHP) has a variable disease course. Computer analysis of CT features was used to identify a subset of CHP patients with an outcome similar to patients with idiopathic pulmonary fibrosis (IPF).MethodsConsecutive patients with a multi-disciplinary team diagnosis of CHP (n = 116) had pulmonary function tests (FEV1, FVC, DLco, Kco, and a composite physiologic index [CPI]) and CT variables predictive of mortality evaluated by analysing visual and computer-based (CALIPER) parenchymal features: total interstitial lung disease (ILD) extent, honeycombing, reticular pattern, ground glass opacities, pulmonary vessel volume (PVV), emphysema, and traction bronchiectasis. Mean survival was compared between both CHP and IPF patients (n = 185).ResultsIn CHP, visual/CALIPER measures of reticular pattern, honeycombing, visual traction bronchiectasis, and CALIPER ILD extent were predictive of mortality (p < 0 · 05) on univariate analysis. PVV was strongly predictive of mortality on univariate (p < 0 · 0001) and multivariate analysis independent of age, gender and disease severity (represented by the CPI [p < 0 · 01]). CHP patients with a PVV threshold >6 · 5% of the lung had a mean survival (35 · 3 ± 6 · 1 months; n = 20/116 [17%]) and rate of disease progression that closely matched IPF patients (38 · 4 ± 2 · 2 months; n = 185).ConclusionsPulmonary vessel volume can identify CHP patients at risk of aggressive disease and a poor IPF-like prognosis.

Esophageal dilatation and interstitial lung disease in systemic sclerosis: A cross-sectional study.

A patulous esophagus on high-resolution computed tomography (HRCT) of the thorax is frequently observed in patients with systemic sclerosis (SSc). Microaspiration has been purported to play a role in the development and progression of SSc interstitial lung disease (ILD), but studies examining the role of microaspiration in SSc ILD have yielded conflicting results. This study was conducted to determine the association between esophageal diameter and SSc ILD. A cross-sectional study of Northwestern Scleroderma Registry patients with available HRCT exams was conducted. The predictor variable was the widest esophageal diameter (WED) on HRCT, and the primary and secondary outcome variables were radiographic ILD and pulmonary function tests respectively. The degree of radiographic ILD was assessed using a semi-quantitative score adapted from published methods. Estimated regression coefficients adjusted for age, sex, race, body mass index, smoking; SSc disease subtype, serum autoantibodies, and disease duration; modified Rodnan skin score, proton pump inhibitor, and immune suppressant medication use and erythrocyte sedimentation rate were calculated. A total of 270 subjects were studied. In the adjusted analyses, there were positive associations between WED and total ILD score (β = 0.27; 95% CI: 0.09-0.41), fibrosis (β = 0.15; 95% CI: 0.07-0.23), and ground glass opacities (β = 0.12; 95% CI: 0.04-0.20); there were negative associations between WED and FVC % predicted (β = -0.42; 95% CI: -0.69 to -0.13), and adjusted DLCO % predicted (β = -0.45; 95% CI: -0.80 to -0.09) after adjusting for potential confounders. Increasing esophageal diameter on HRCT in patients with SSc is associated with more severe radiographic ILD, lower lung volumes, and lower DLCO % predicted. Longitudinal studies are needed to determine if esophageal dilatation is associated with the incidence and/or progression of ILD in patients with SSc.

Relationship between quantitative radiographic assessments of interstitial lung disease and physiological and clinical features of systemic sclerosis

ObjectivesExtent of systemic sclerosis (SSc)-related interstitial lung disease (ILD) assessed from thoracic high-resolution CT (HRCT) predicts disease course, mortality and treatment response. While quantitative HRCT analyses of extent of lung...

Automated 3D Ιnterstitial Lung Disease Εxtent Quantification: Performance Evaluation and Correlation to PFTs

In this study, the performance of a recently proposed computer-aided diagnosis (CAD) scheme in detection and 3D quantification of reticular and ground glass pattern extent in chest computed tomography of interstitial lung disease (ILD) patients is evaluated. CAD scheme performance was evaluated on a dataset of 37 volumetric chest scans, considering five representative axial anatomical levels per scan. CAD scheme reliability analysis was performed by estimating agreement (intraclass correlation coefficient, ICC) of automatically derived ILD pattern extent to semi-quantitative disease extent assessment in terms of 29-point rating scale provided by two expert radiologists. Receiver operating characteristic (ROC) analysis was employed to assess CAD scheme accuracy in ILD pattern detection in terms of area under ROC curve (A z ). Correlation of reticular and ground glass volumetric pattern extent to pulmonary function tests (PFTs) was also investigated. CAD scheme reliability was substantial for ILD extent (ICC = 0.809) and distinct reticular pattern extent (0.806) and moderate for distinct ground glass pattern extent (0.543), performing within inter-observer agreement. CAD scheme demonstrated high accuracy in detecting total ILD (A z = 0.950 ± 0.018), while accuracy in detecting distinct reticular and ground glass patterns was 0.920 ± 0.023 and 0.883 ± 0.024, respectively. Moderate and statistically significant negative correlation was found between reticular volumetric pattern extent and diffusing capacity, forced expiratory volume in 1s, forced vital capacity, and total lung capacity (R = -0.581, -0.513, -0.494, and -0.446, respectively), similar to correlations found between radiologists' semi-quantitative ratings with PFTs. CAD-based quantification of disease extent is in agreement with radiologists' semi-quantitative assessment and correlates to specific PFTs, suggesting a potential imaging biomarker for ILD staging and management.

Interstitial lung diseases in Saudi Arabia: A single-center study

BACKGROUND:There are relatively few epidemiological studies on interstitial lung disease (ILD) worldwide.OBJECTIVE:To report the incident cases of ILD and compare our data with reports from other populations.METHODS:Newly diagnosed ILDs were prospectively collected at a single tertiary care hospital from January 2008 to December 2011. Detailed demographic and clinical data were collected at the time of diagnosis, along with the results from diagnostic procedures, including high-resolution computed tomography (HRCT), serological tests, bronchoalveolar lavage (BAL), transbronchial lung biopsy, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and surgical lung biopsy.RESULTS:A total of 330 cases were included. The mean age was 55.4 ± 14.9 years. There was a slight predominance of females (202; 61.2%), and the male-to-female ratio was 1:1.37. The most frequent disease was connective tissue disease (CTD)-associated ILD (34.8%), followed by idiopathic pulmonary fibrosis (IPF) (23.3%), sarcoidosis (20%), and hypersensitivity pneumonitis (6.3%). Non-classifiable ILD was present in 1.8% of the total ILD cases. HRCT was performed in 97.3% of the cases, BAL in 17.5%, transbronchial lung biopsy in 21.8%, EBUS-TBNA in 4.5%, and surgical lung biopsy in 22.7% (38.6% of which were performed among the idiopathic interstitial pneumonia cases).CONCLUSIONS:CTD-ILD and IPF were the most frequently observed ILDs in this Saudi Arabian population. Similarities and differences were found with respect to the previous reports from other countries.