High-resolution computed tomography to differentiate chronic diffuse interstitial lung diseases with predominant ground-glass pattern using logical analysis of data.

OBJECTIVES: We evaluated the performance of high-resolution computed tomography (HRCT) to differentiate chronic diffuse interstitial lung diseases (CDILD) with predominant ground-glass pattern by using logical analysis of data (LAD). METHODS: A total of 162 patients were classified into seven categories: sarcoidosis (n = 38), connective tissue disease (n = 32), hypersensitivity pneumonitis (n = 18), drug-induced lung disease (n = 15), alveolar proteinosis (n = 12), idiopathic non-specific interstitial pneumonia (n = 10) and miscellaneous (n = 37). First, 40 CT attributes were investigated by the LAD to build up patterns characterising a category. From the association of patterns, LAD determined models specific to each CDILD. Second, data were recomputed by adding eight clinical attributes to the analysis. The 20 x 5 cross-folding method was used for validation. RESULTS: Models could be individualised for sarcoidosis, hypersensitivity pneumonitis, connective tissue disease and alveolar proteinosis. An additional model was individualised for drug-induced lung disease by adding clinical data. No model was demonstrated for idiopathic non-specific interstitial pneumonia and the miscellaneous category. The results showed that HRCT had a good sensitivity (>or=64%) and specificity (>or=78%) and a high negative predictive value (>or=93%) for diseases with a model. Higher sensitivity (>or=78%) and specificity (>or=89%) were achieved by adding clinical data. CONCLUSION: The diagnostic performance of HRCT is high and can be increased by adding clinical data.

Pulmonary cavitary sarcoidosis: clinico-radiologic characteristics and natural history of a rare form of sarcoidosis.

Pulmonary cavitary lesions in the absence of concomitant comorbidities are an uncommon and often confusing manifestation of sarcoidosis. We retrospectively reviewed the clinical and high-resolution computed tomography (HRCT) characteristics and the natural history of a series of 23 patients with pulmonary cavitary lesions found on HRCT extracted from a large cohort of patients with pulmonary sarcoidosis. The estimated prevalence of cavitary sarcoidosis was 2.2%. Cavitary lesions developed in patients with severe and active sarcoidosis (serum angiotensin-converting enzyme [SACE] > or =2 times the upper limit of normal range: 63.6%). Twelve (52.2%) patients had evidence of radiographic stage IV, 9 of whom (75%) had persistently increased SACE. As found on HRCT, cavitary lesions were multiple in 21 patients (91.3%), including 5 patients with 10 or more cavities. The size of cavitary lesions was variable, with a median diameter of 20 mm (range, 11-100 mm). Follow-up was available for 20 patients with a median follow-up of 6.25 years (range, 6 months to 15 years). Seven patients (35%) experienced some type of complication related to cavitary lesions, including 6 episodes of hemoptysis in 5 patients and aspergilloma occurrence in 3 patients. As seen on HRCT, the evolution of the number and size of cavitary lesions was variable, with a complete resolution of the largest cavitary lesion in only 5 patients (25%). During follow-up, wall thickening was always associated with a further infectious complication. In summary, cavitary lesions are rare in pulmonary sarcoidosis and usually occur in active and severe sarcoidosis. Their evolution is unpredictable, and complications are frequent.

Imaging in sarcoidosis.

Sarcoidosis is a multisystemic granulomatous disease of unknown etiology that may involve virtually any organ. Pulmonary involvement predominates, but sarcoidosis can involve multiple organs, with or without concomitant lung involvement. Aberrations on chest radiographs are present in more than 90% of patients with sarcoidosis. Bilateral hilar lymphadenopathy, with or without lung parenchymal infiltrates, is typical but a wide range of chest radiographic patterns may be observed. This article discusses the characteristic chest radiographic features of sarcoidosis and the prognostic value of the radiographic staging classification as espoused by Scadding more than 4 decades ago. Thin-section high-resolution computed tomographic (HRCT) scans more clearly elucidate the intrathoracic lesions observed in sarcoidosis and may discriminate active inflammation from end-stage fibrosis. Although HRCT is not necessary to manage all cases of sarcoidosis, HRCT may be invaluable in SELECTED patients with stage II or III sarcoidosis to discriminate alveolitis (which may be amenable to therapy) from fibrosis. Additionally, radionuclide techniques may have a role in extrapulmonary sarcoidosis (particularly when central nervous system or cardiac involvement is suspected). We review the salient features and role of magnetic resonance imaging and diverse radionuclide techniques to diagnose or follow selected cases of extrapulmonary sarcoidosis.

[Imaging findings in interstitial lung disease]. / Les données de l'imagerie dans les pneumopathies infiltrantes diffuses.

Imaging is an essential step in the management of patients with interstitial lung disease, contributing to detection, diagnosis, evaluation of pulmonary damage and prognosis, surveillance, and screening for complications. The chest x-ray is the fundamental examination. High-resolution computed tomography is often useful, particularly for severe forms and for cases of difficult diagnosis. It should not however be used as a routine examination for the initial work-up nor repeated systematically. Computed tomography is more contributory to the diagnosis of subacute or chronic interstitial pneumonia than for acute forms. We present here the different imaging methods, the role of imaging in chronic and acute interstitial pneumonia, and discuss the main computed tomographic signs of chronic interstitial lung disease.

CT findings in severe thoracic sarcoidosis.

Severe thoracic sarcoidosis includes manifestations with significant clinical and functional impairment and a risk of mortality. Severe thoracic sarcoidosis can take on various clinical presentations and is associated with increased morbidity. The purpose of this article was to describe the CT findings in severe thoracic sarcoidosis and to explain some of their mechanisms. Subacute respiratory insufficiency is a rare and early complication due to a high profusion of pulmonary lesions. Chronic respiratory insufficiency due to pulmonary fibrosis is a frequent and late complication. Three main CT patterns are identified: bronchial distortion, honeycombing and linear opacities. CT can be helpful in diagnosing some mechanisms of central airway obstruction such as bronchial distortion due to pulmonary fibrosis or an extrinsic bronchial compression by enlarged lymph nodes. An intrinsic narrowing of the bronchial wall by endobronchial granulomatous lesions may be suggested by CT when it shows evidence of bronchial mural thickening. Pulmonary hypertension usually occurs in patients with end-stage pulmonary disease and is related to fibrotic destruction of the distal capillary bed and to the resultant chronic hypoxemia. Several other mechanisms may contribute to the development of pulmonary hypertension including extrinsic compression of major pulmonary arteries by enlarged lymph nodes and secondary pulmonary veno-occlusive disease. Aspergilloma colonization of a cavity is the main cause of hemoptysis in sarcoidosis. Other rare causes are bronchiesctasis, necrotizing bronchial aspergillosis, semi-invasive pulmonary aspergillosis, erosion of a pulmonary artery due to a necrotic sarcoidosis lesion, necrosis of parenchymal sarcoidosis lesions and specific endobronchial macroscopic lesions.

Pulmonary cryptococcosis.

Pulmonary cryptococcosis is the consequence of the inhalation of Cryptococcus neoformans, an encapsulated yeast, from various environmental sources. It is commonly accepted that the acquisition of the disease occurs early in life and that the disease is mostly related to a reactivation from a pulmonary site in immunocompromised hosts such as patients infected with human immunodeficiency virus. Clinical and radiological presentations of the disease are nonspecific and are more severe in immunocompromised hosts with acquired immunodeficiency syndrome (AIDS). However, fulminant forms have also been reported in apparently immunocompetent hosts. C. neoformans has rarely been responsible for colonization of the respiratory tract; this usually occurs in immunocompetent hosts with preexisting pulmonary disease. Diagnosis of pneumonia is obtained by either analysis of bronchoalveolar lavage in AIDS patients or by the histology/mycological analysis of a pulmonary nodule. In any case, a careful work-up for diagnosing dissemination should always be performed. Antifungal treatment has to be given in most of the immunocompetent hosts and always in those with any kind of immunodeficiency with isolated pulmonary cryptococcosis.

Thin-section chest CT findings of primary Sjögren's syndrome: correlation with pulmonary function.

The purpose of this study was to describe thin-section CT findings of lung involvement in patients with primary Sjögren's syndrome (PSS), and to correlate them with pulmonary function tests (PFT). The chest thin-section CT examinations of 35 patients with proven diagnosis of PSS and respiratory symptoms were retrospectively assessed by two observers, in a first step independently with interobserver evaluation, and in a second step in consensus. The extent of the most frequent CT findings was scored. Correlation was made with PFT in 31 of these patients. Three main CT patterns were identified with good interobserver agreement (kappa coefficient 0.71): 19 of 35 (54%) large and/or small airways disease; 7 of 35 (20%) interstitial lung fibrosis (ILF); and 5 of 35 (14%) suggestive of lymphocytic interstitial pneumonia (LIP). The CT scans were normal in 2 patients (6%) and showed only dilatation of pulmonary vessels due to pulmonary arterial hypertension in two others (6%). Airway disease patients had predominantly obstructive profiles (mean FEV(1)/FVC ratio 69.7+/-12.7%, mean MEF(25) 50.1+/-22.9%), whereas patients with ILF and LIP had predominantly restrictive profiles and/or a decreased diffusing lung capacity (mean TLC 87.0+/-26.0 and 64.6+/-18.6%, mean DL(CO) 57.4+/-21.2 and 52.0+/-8.0%). Significant correlation ( p<0.01) was found between the scores of ground-glass attenuation and TLC ( r=-0.84) and DL(CO) ( r=-0.70) and between the score of air trapping and FEV1 ( r=-1.0). In patients with PSS and respiratory symptoms, thin-section CT may provide characterization of lung involvement which correlates with pulmonary function.

New frontiers in CT imaging of airway disease.

Combining helical volumetric CT acquisition and thin-slice thickness during breath hold provides an accurate assessment of both focal and diffuse airway diseases. With multiple detector rows, compared with single-slice helical CT, multislice CT can cover a greater volume, during a simple breath hold, and with better longitudinal and in-plane spatial resolution and improved temporal resolution. The result in data set allows the generation of superior multiplanar and 3D images of the airways, including those obtained from techniques developed specifically for airway imaging, such as virtual bronchography and virtual bronchoscopy. Complementary CT evaluation at suspended or continuous full expiration is mandatory to detect air trapping that is a key finding for depicting an obstruction on the small airways. Indications for CT evaluation of the airways include: (a) detection of endobronchial lesions in patients with an unexplained hemoptysis; (b) evaluation of extent of tracheobronchial stenosis for planning treatment and follow-up; (c) detection of congenital airway anomalies revealed by hemoptysis or recurrent infection; (d) detection of postinfectious or postoperative airway fistula or dehiscence; and (e) diagnosis and assessment of extent of bronchiectasis and small airway disease. Improvement in image analysis technique and the use of spirometrically control of lung volume acquisition have made possible accurate and reproducible quantitative assessment of airway wall and lumen areas and lung density. This contributes to better insights in physiopathology of obstructive lung disease, particularly in chronic obstructive pulmonary disease and asthma.