Role of High-Resolution CT Thorax in Diagnosing Interstitial Lung Disease and Its Association With Smoking and Connective Tissue Disorder.

Introduction Interstitial lung diseases (ILDs) primarily affect the interstitium, an alveolar wall tissue between the capillary endothelium and the alveolar epithelium. The term 'interstitial,' however, is misleading since alveolar spaces, peripheral airways, and vessels can be involved in most of these disorders.They often require a multidisciplinary diagnosis i.e., an integration of clinical, radiological, and pathological findings. A chest radiograph is relatively insensitive because of nonspecific patterns. Generally, these disorders can progress to irreversible pulmonary fibrosis and are an important cause of morbidity and mortality. It is critical to make a prompt and accurate diagnosis of the underlying causes so that patients can be managed appropriately. ILD is subdivided into idiopathic interstitial pneumonia, of which idiopathic pulmonary fibrosis (IPF) is one subset, and diffuse parenchymal lung diseases, which may be secondary to a variety of occupational or environmental exposures or others. They can complicate multiple rheumatic or connective tissue diseases (CTDs). Apart from ILD, other forms of lung damage involving the pleura, vasculature, airways, and lymphatic tissue can complicate CTDs. Aims  Aims include studying the role of high-resolution computed tomography (HRCT) in diagnosing various ILDs based on morphologic patterns, evaluating the correlation between ILD and various connective tissue disorders and the prevalence of complications in such patients, and evaluating the association of smoking with various ILDs. Methods This is a retrospective study in which HRCT thorax was performed on a 128-slice Philips CT scanner machine on 50 patients from December 2020 to February 2022 in SVP Hospital, Ahmedabad. No age or gender bias was followed. Result Out of 50 patients studied, 19 (38%) patients had the usual interstitial pneumonia (UIP) pattern and 12 (24%) had the nonspecific interstitial pneumonia (NSIP) pattern. These two were the most common among all ILD patterns. Other patterns found were hypersensitivity pneumonitis (5; 10%), respiratory bronchiolitis-related ILD (3;6%), and organizing pneumonia (2; 4%). In nine patients, the morphologic pattern was either subtle (3; 6%) or mixed (6; 12%), and the final diagnosis remained inconclusive; patients were advised clinical correlation and biopsy. Eleven (22%) patients had a history of smoking. Among smokers, the most common pattern was UIP while all patients with respiratory bronchiolitis (RB) ILD had a history of smoking. Fourteen (28%) patients showed a positive association with CTD. Among them, rheumatoid arthritis (RA) was the most common CTD and the most common pattern among RA patients was UIP. Ten (20%) of patients developed pulmonary arterial hypertension, of which two patients who had connective tissue disorder developed pulmonary arterial hypertension at a young age (24 years). The rest of the patients who developed pulmonary arterial hypertension were above 45 years of age. Among these, two were smokers. Conclusion HRCT plays an important role in the diagnosis of ILD on the basis of various morphological patterns. CTD plays a significant role in the development of ILD. UIP is the most common ILD among patients with a smoking history and RA. NSIP Is the most common in patients with CTD other than RA. Pulmonary arterial hypertension (PAH) develops early in patients with CTD. There is a significant risk of the development of PAH in patients with chronic ILD.

Doshi JA ，Mundhra KS ，Shah DS ，Shah SN ，Patel TV ，Bhatt A ... -  《Cureus》

Connective tissue disease-related interstitial lung disease (CTD-ILD) and interstitial lung abnormality (ILA): Evolving concept of CT findings, pathology and management.

Connective tissue diseases (CTDs) demonstrating features of interstitial lung disease (ILD) include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), dermatomyositis (DM) and polymyositis (PM), ankylosing spondylitis (AS), Sjogren syndrome (SS), and mixed connective tissue disease (MCTD). On histopathology of lung biopsy in CTD-related ILDs (CTD-ILDs), multi-compartment involvement is an important clue, and when present, should bring CTD to the top of the list of etiologic differential diagnoses. Diverse histologic patterns including nonspecific interstitial pneumonia (NSIP), usual interstitial pneumonia (UIP), organizing pneumonia, apical fibrosis, diffuse alveolar damage, and lymphoid interstitial pneumonia can be seen on histology in patients with CTD-ILDs. Although proportions of ILDs vary, the NSIP pattern accounts for a large proportion, especially in SSc, DM and/or PM and MCTD, followed by the UIP pattern. In RA patients, interstitial lung abnormality (ILA) is reported to occur in approximately 20-60% of individuals of which 35-45% will have progression of the CT abnormality. Subpleural distribution and greater baseline ILA involvement are risk factors associated with disease progression. Asymptomatic CTD-ILDs or ILA patients with normal lung function and without evidence of disease progression can be followed without treatment. Immunosuppressive or antifibrotic agents for symptomatic and/or fibrosing CTD-ILDs can be used in patients who require treatment.

Yoo H ，Hino T ，Hwang J ，Franks TJ ，Han J ，Im Y ，Lee HY ，Chung MP ，Hatabu H ，Lee KS ... -  《European Journal of Radiology Open》

Connective tissue disease-related interstitial lung disease (CTD-ILD) and interstitial lung abnormality (ILA): Evolving concept of CT findings, pathology and management.

The connective tissue diseases (CTDs) demonstrating features of interstitial lung disease (ILD) include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), progressive systemic sclerosis (PSS), dermatomyositis (DM) and polymyositis (PM), ankylosing spondylitis (AS), Sjogren's syndrome (SS), and mixed connective tissue disease (MCTD). In RA patients in particular, interstitial lung abnormality (ILA) (of varying degrees; severe vs. mild) is reported to occur in approximately 20-60 % of individuals and CT disease progression occurs in approximately 35-45 % of them. The ILAs have been associated with a spectrum of functional and physiologic decrement. The identification of progressive ILA may enable appropriate surveillance and the commencement of treatment with the goal of improving morbidity and mortality rates of established RA-ILD. Subpleural distribution and higher baseline ILA/ILD extent were risk factors associated with disease progression. At histopathologic analysis, connective tissue disease-related interstitial lung diseases (CTD-ILDs) are diverse and include nonspecific interstitial pneumonia (NSIP), usual interstitial pneumonia (UIP), organizing pneumonia (OP), apical fibrosis, diffuse alveolar damage (DAD), and lymphoid interstitial pneumonia (LIP). Even though proportions of ILDs vary, NSIP pattern accounts for a large proportion, especially in PSS, DM/PM and MCTD, followed by UIP pattern. Evidence has been published that treatment of subclinical CT lung abnormalities showing a tendency to progress to ILD may stabilize the CT alterations. The identification of subclinical lung abnormalities can be appropriate in the management of the disease and CT appears to be the gold standard for the evaluation of lung parenchyma.

Yoo H ，Hino T ，Han J ，Franks TJ ，Im Y ，Hatabu H ，Chung MP ，Lee KS ... -  《European Journal of Radiology Open》

Comparison of clinical courses and mortality of connective tissue disease-associated interstitial pneumonias and chronic fibrosing idiopathic interstitial pneumonias.

Interstitial lung disease (ILD) is a common pulmonary manifestation of connective tissue diseases (CTD). Prognostic effect of radiological usual interstitial pneumonia (UIP) pattern in CTD-associated interstitial lung disease (CTD-ILD) is unknown. This study aimed to investigate the disease progression and mortality of patients with CTD-ILD and idiopathic interstitial pneumonias (IIP) including idiopathic pulmonary fibrosis (IPF) and idiopathic nonspecific interstitial pneumonia and the prognostic impact of the radiological UIP pattern on both disease groups. The medical records of 91 patients (55 with CTD-ILD and 36 with IIP) diagnosed with ILD at pulmonary medicine department, Faculty of Medicine, Gazi University from 2004 to 2014 were retrospectively reviewed. Patients included whose baseline high-resolution computed tomography (HRCT) scans showed either a UIP or non-UIP pattern. While 67.3% (n = 37) of CTD-ILD patients possessed UIP pattern, 38.9% (n = 14) of IIP patients had UIP pattern in HRCT. Respiratory functions including the forced expiratory volume in the first second (FEV1 ), functional vital capacity (FVC), and transfer coefficient for carbon monoxide (diffusing capacity of the lung for carbon monoxide [DLCO]) of IIP group at the time of diagnosis were significantly lower than CTD-ILD group (P = .007, P = .002, and P = .019, respectively). There was no significant survival difference between CTD-ILD and IIP by using the log-rank test (P = .76). Multivariate analysis revealed that UIP pattern in HRCT (Hazard ratio: 1.85; 95% Confidence interval = 1.14-3; P = .013), annual FVC (Hazard ratio: 0.521; 95% Confidence interval = 0.32-0.84; P = .007), and annual DLCO declines (Hazard ratio: 0.943; 95% Confidence interval = 0.897-0.991; P = .02) were independent risk factors for mortality in both CTD-ILD and IIP groups. We found that UIP pattern in HRCT and annual losses in respiratory functions were the main determinants of prognosis of ILDs either idiopathic or CTD-associated.

Yıldırım F ，Türk M ，Bitik B ，Erbaş G ，Köktürk N ，Haznedaroğlu Ş ，Türktaş H ... -  《-》

Review series: Aspects of interstitial lung disease: connective tissue disease-associated interstitial lung disease: how does it differ from IPF? How should the clinical approach differ?

de Lauretis A ，Veeraraghavan S ，Renzoni E 《-》