Mimics in chest disease: interstitial opacities

Abstract

Septal, reticular, nodular, reticulonodular, ground-glass, crazy paving, cystic, ground-glass with reticular, cystic with ground-glass, decreased and mosaic attenuation pattern characterise interstitial lung diseases on high-resolution computed tomography (HRCT). Occasionally different entities mimic each other, either because they share identical HRCT findings or because of superimposition of patterns. Idiopathic pulmonary fibrosis (IPF), fibrosis associated with connective tissue disease, asbestosis, end-stage sarcoidosis or chronic hypersensitivity pneumonitis (HP) may present with lower zone, subpleural reticular pattern associated with honeycombing. Lymphangiomyomatosis may be indistinguishable from histiocytosis or extensive emphysema. Both pulmonary oedema and lymphangitic carcinomatosis may be characterised by septal pattern resulting from thickened interlobular septa. Ill-defined centrilobular nodular pattern may be identically present in HP and respiratory bronchiolitis–associated with interstitial lung disease (RBILD). Sarcoidosis may mimic miliary tuberculosis or haematogenous metastases presenting with miliary pattern, while endobronchial spread of tuberculosis may be indistinguishable from panbronchiolitis, both presenting with tree-in-bud pattern. Atypical infection presenting with ground-glass mimics haemorrhage. Ground-glass pattern with minimal reticulation is seen in desquamative interstitial pneumonia (DIP), RBILD and non-specific interstitial pneumonia (NSIP). Obliterative bronchiolitis and panlobular emphysema may present with decreased attenuation pattern, while obliterative bronchiolitis, chronic pulmonary embolism and HP may manifest with mosaic attenuation pattern. Various mimics in interstitial lung diseases exist. Differential diagnosis is narrowed based on integration of predominant HRCT pattern and clinical history.Teaching Points• To learn about the different HRCT patterns, which are related to interstitial lung diseases.• To be familiar with the more “classical” entities presenting with each HRCT pattern.• To discuss possible overlap of different HRCT patterns and the more common mimics in each case.• To learn about some clues that help differentiate the various diagnostic mimics on HRCT.

Increased Expression of CC16 in Patients with Idiopathic Pulmonary Fibrosis

“…The differential diagnosis of IPF with other chronic fibrosing lung disorders that exhibit an UIP pattern may be extremely difficult [1, 7, 8, 29]. In general, clinicians face two challenges for the confident diagnosis of IPF: a) the patient has IPF but the tomographic and/or morphologic findings are atypical, or b) the patient has another chronic fibrotic lung disorder with UIP-like pattern.…”

High-Resolution Transthoracic Ultrasonography for Assessment of Pleural Lines in Patients With Dyspnea With CT Comparison: An Observational Study

“…34 Reticular pattern is usually present in the lung periphery (as a result of which TUS displays high sensitivity; see Table 1) and represents intralobular and interlobular septa thickening and honeycombing. 35 Previous studies have shown that the presence of multiple B-lines with distances of 3 and 7 mm are representative of groundglass and of subpleura interlobular septa thickening, respectively. 11,14 In one study of 61 patients with interstitial lung disease, the distance between each two adjacent B-line correlated with the degree of interstitial affection on chest HRCT (Warrick score).…”

“…Computed tomography is considered a sensitive diagnostic tool for confirmation of pulmonary fibrosis . Reticular pattern is usually present in the lung periphery (as a result of which TUS displays high sensitivity; see Table ) and represents intralobular and interlobular septa thickening and honeycombing . Previous studies have shown that the presence of multiple B‐lines with distances of 3 and 7 mm are representative of ground‐glass and of subpleura interlobular septa thickening, respectively .…”

Cystic and Nodular Lung Disease

“…68 Approaching nodular lung disease often requires a multimodal approach, with close cooperation among clinicians, pathologists, and radiologists to reach an accurate, focused differential diagnosis. HRCT is a particularly useful modality in characterizing nodular lung disease, with the most useful clue being the distribution pattern relative to the SPL.…”