Imaging diagnosis of classical and new pneumoconiosis: predominant reticular HRCT pattern

Abstract

Our understanding of the manifestations of pneumoconioses is evolving in recent years. Associations between novel exposures and diffuse interstitial lung disease have been newly recognized. In advanced asbestosis, two types of fibrosis are seen, probably related to dose of exposure, existence of pleural fibrosis, and the host factor status of the individual. In pneumoconiosis of predominant reticular type, nodular opacities are often seen in the early phase. The nodular pattern is centrilobular, although some in metal lung show perilymphatic distribution, mimicking sarcoidosis. High-resolution computed tomography enables a more comprehensive correlation between the pathologic findings and clinically relevant imaging findings. The clinician must understand the spectrum of characteristic imaging features related to both known dust exposures and to historically recent new dust exposures.

Keywords: Asbestosis; HRCT; Metal lung disease; Pneumoconiosis.

Fig. 1

Subpleural dots and subpleural lines in asbestosis. Some dots are located a few millimeters from the pleura (arrows). In asbestosis, subpleural line is much closer to the pleural surface and the distance of the subpleural lines from the inner chest wall is 2 to 3 mm (arrowheads). The subpleural lines look like connected subpleural dots arranged along the inner chest wall

Fig. 2

Two types of advanced asbestosis. a A honeycomb type of asbestosis. Postmortem low-kilovoltage radiograph and HRCT scan of the inflated and fixed left lung shows honeycombing in the lower two-thirds of the lung. In the subpleural zones of upper lung, dot-like lesions are seen (arrows). b An atelectatic fibrosis type of asbestosis. Postmortem low-kilovoltage radiograph and HRCT scan of the inflated and fixed left lung shows diffuse pleural thickening and consolidated area extending along the bronchovascular sheath. Traction bronchiectasis is seen in the consolidated area. Honeycombing is not seen radiologically. In the subpleural zones of upper lung, subpleural dots and subpleural lines are also seen (arrows)

Fig. 3.

61-year-old man with inhalational talc pneumoconiosis employed in talc industry for 20 years. a HRCT scan shows diffusely distributed small nodules. They are separated from the pulmonary vein or the pleura at a distance of about 2–3 mm and are separated regularly from each other at a distance of about 2–3 mm. b CT scan at mediastinal setting of 61-year-old man with inhalational talc pneumoconiosis shows large opacity and lymph nodes containing high-attenuation material

Fig. 4

HRCT scans of pulmonary aluminosis. a 58-year-old man with pulmonary aluminosis. HRCT scan of pulmonary aluminosis mimicking sarcoidosis. Ground-glass opacities, small nodular opacities, and traction bronchiectasis are seen predominantly around the bronchovascular bundles. Nodules are located in both centrilobular and paralobular regions. b 52-year-old man with pulmonary aluminosis. HRCT shows traction bronchiectasis and ground-glass opacity predominantly in the upper lungs. Multiple bullae and centrilobular nodules are also seen

Fig. 5

HRCT scans of heard metal pneumoconiosis. a 62-year-old man with hard metal pneumoconiosis. Upper-lung predominant fibrosis in hard metal pneumoconiosis. HRCT scan shows prominent interstitial thickening, irregular peribronchovascular thickening, and traction bronchiectasis in upper lung zones. b 32-year-old man with hard metal pneumoconiosis. Early stage of hard metal pneumoconiosis. HRCT scan shows ground-glass opacities and centrilobular nodules predominantly in the peripheral portions. c 53-year-old man with hard metal pneumoconiosis. HRCT scan shows patchy and irregular ground-glass opacity and traction bronchiectasis diffusely distributed in the lung. Bullae are seen in the subpleural region.

Fig. 6.

59-year-old man with hard metal pneumoconiosis. Initial HRCT scan (a) shows scattered areas of ground-glass attenuation associated with fine reticulation and mild traction bronchiectasis. HRCT obtained 3 years later (b) reveals increase in parenchymal abnormalities in extent, prominent reticulation, and progression of traction bronchiectasis. HRCT obtained 5 years later (c) shows dense increased parenchymal opacities with traction bronchiectasis

Fig. 7

HRCT scan of a 34-year-old man with indium lung. Tiny centrilobular nodules (arrows) are scattered in both lungs