Korean J Radiol.  2015 Oct;16(5):1142-1152. 10.3348/kjr.2015.16.5.1142.

CT Characteristics of Pleural Plaques Related to Occupational or Environmental Asbestos Exposure from South Korean Asbestos Mines

• Kim Y
• Myong JP
• Lee JK
• Kim JS
• Kim YK
• Jung SH

• KMID: 2160782
• DOI: http://doi.org/10.3348/kjr.2015.16.5.1142

Abstract

OBJECTIVE
This study evaluated the CT characteristics of pleural plaques in asbestos-exposed individuals and compared occupational versus environmental exposure groups.
MATERIALS AND METHODS
This study enrolled 181 subjects with occupational exposure and 98 with environmental exposure from chrysotile asbestos mines, who had pleural plaques confirmed by a chest CT. The CT scans were analyzed for morphological characteristics, the number and distribution of pleural plaques and combined pulmonary fibrosis. Furthermore, the CT findings were compared between the occupational and environmental exposure groups.
RESULTS
Concerning the 279 subjects, the pleural plaques were single in 2.2% and unilateral in 3.6%, and showed variable widths (range, 1-20 mm; mean, 5.4 +/- 2.7 mm) and lengths (5-310 mm; 72.6 +/- 54.8 mm). The chest wall was the most commonly involved (98.6%), with an upper predominance on the ventral side (upper, 77.8% vs. lower, 55.9%, p < 0.001) and a lower predominance on the dorsal side (upper, 74.9% vs. lower, 91.8%, p = 0.02). Diaphragmatic involvement (78.1%) showed a right-side predominance (right, 73.8% vs. left, 55.6%, p < 0.001), whereas mediastinal plaques (42.7%) were more frequent on the left (right, 17.6% vs. left, 39.4%, p < 0.001). The extent and maximum length of plaques, and presence and severity of combined asbestosis, were significantly higher in the occupational exposure group (p < 0.05).
CONCLUSION
Pleural plaques in asbestos-exposed individuals are variable in number and size; and show a predominant distribution in the upper ventral and lower dorsal chest walls, right diaphragm, and left mediastinum. Asbestos mine workers have a higher extent of plaques and pulmonary fibrosis versus environmentally exposed individuals.

Keyword

Pleural plaques; Asbestos; Computed tomography; Occupational diseases

MeSH Terms

Adult
Aged
Aged, 80 and over
Asbestos, Serpentine/*toxicity
Asbestosis/*etiology/radiography
Asian Continental Ancestry Group
Environmental Pollutants/toxicity
Female
Humans
Male
Middle Aged
Mining
Occupational Exposure
Pleural Diseases/*etiology/radiography
Republic of Korea
Tomography, X-Ray Computed
Asbestos, Serpentine
Environmental Pollutants

Figure

• 

  Fig. 1 Single pleural plaque in 61-year-old man who lived within 2 km of chrysotile asbestos mine for 40 years. Chest radiograph (A) shows calcified pleural plaque in left hemithorax (arrow). CT scan (B) shows thin calcified plaque along left anterior chest wall (arrow).

• 

  Fig. 2 Pleural plaques in 75-year-old man who lived for 2 years within 1 km of asbestos mine 45 years ago and worked as construction worker for 30 years. CT scan at upper chest wall (A) shows multiple calcified plaques (arrows) located predominantly in ventral side, whereas CT scan at lower chest wall (B) demonstrates plaques (arrows) on dorsal side. Also noted are mediastinal pleural plaques (arrowheads).

• 

  Fig. 3 Asbestos pleural plaques involving diaphragmatic pleura. Multiple non-calcified (A, B) and calcified (C) pleural plaques of variable sizes (arrows) are noted along right diaphragm. Diaphragmatic plaques were more frequently observed on right in this study.

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  Fig. 4 Mediastinal pleural plaques in asbestos-exposed individuals. A. Thin pleural plaque (arrow) is noted along left mediastinal pleura. Also noted are thin sheet-like plaques along posterior chest wall (arrowheads). B. Heavily calcified plaques are noted along both sides of mediastinum. Tiny plaque is noted in left posterior chest wall (arrowhead).

• 

  Fig. 5 Relationship between duration of asbestos exposure and maximum pleural plaque length in occupational and environmental asbestos exposure groups, visualized using locally weighted scatterplot smoothing regression fit modeling. Significant correlation was observed between asbestos exposure duration and maximum plaque length in occupational exposure group (p = 0.049) but not in environmental exposure group (p = 0.099).

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