CT Quantification of Large Opacities and Emphysema in Silicosis: Correlations among Clinical, Functional, and Radiological Parameters

• Published in: Lung Vol. 192; no. 4; pp. 543 - 551
• Main Authors: de Castro, Marcos César Santos, Ferreira, Angela Santos, Irion, Klaus Loureiro, Hochhegger, Bruno, Lopes, Agnaldo José, Velarde, Guilhermo Coca, Zanetti, Gláucia, Marchiori, Edson
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2014; Springer; Springer Nature B.V
• Subjects: Adult; Aged; Automation; Care and treatment; Complications and side effects; Cross-Sectional Studies; CT imaging; Development and progression; Diagnosis; Emphysema; Female; Humans; Lung - diagnostic imaging; Lung - physiopathology; Lung Volume Measurements - methods; Male; Medicine; Medicine & Public Health; Middle Aged; Occupational diseases; Patient outcomes; Pneumology/Respiratory System; Predictive Value of Tests; Pulmonary Diffusing Capacity; Pulmonary Emphysema - diagnostic imaging; Pulmonary Emphysema - physiopathology; Radiographic Image Interpretation, Computer-Assisted; Respiratory system; Severity of Illness Index; Silicosis; Silicosis - diagnostic imaging; Silicosis - physiopathology; Spirometry; Tomography; Tomography, Spiral Computed; Vital Capacity; Brazil; Pulmonary emphysema; Densitometry; Occupational disease; Respiratory function test; Silicosis
• ISSN: 0341-2040; 1432-1750
• DOI: 10.1007/s00408-014-9590-9

Background The assessment of the extent of silicosis on chest radiographs is subjective and could be more standardized by using computed tomography (CT) quantification methods. We propose a semiautomatic method of quantifying the anatomical lung damage (LD) (the sum of the emphysema and large opacities volumes) measured by CT densitovolumetry in complicated silicosis. Methods Twenty-three nonsmokers with complicated silicosis were included. Large opacities were recorded as size A, B, or C according to the size of the opacities on chest radiographs. Pulmonary function tests (PFT) were assessed by spirometry and the carbon monoxide diffusion capacity. Total lung capacity (TLC) was measured by helium dilution, and total lung volume (TLV) was measured by CT quantification (TLVct). CT images were postprocessed using CT densitovolumetry to measure the TLVct, large opacities volume, emphysema volume (EV), and emphysema index (EI). Results Significant correlations were observed between the EV and the forced vital capacity ( r  = 0.41, p  = 0.04), TLC ( r  = 0.44, p  = 0.03), and residual volume (RV) ( r  = 0.49, p  = 0.01). A correlation also was observed between the LD% and RV ( r  = 0.43, p  = 0.03) and between the LD and RV ( r  = 0.47, p  = 0.02). Conclusions The PFT findings were correlated with the EV, EI, LD, and LD%, but they were not correlated with the large opacities volume. These results suggest that the emphysema volume, more than the large opacities volume, is responsible for functional impairment in patients with complicated silicosis.