OBJECTIVETo study the diagnostic value of CT/HRCT for the coal workers' pneumoconiosis (CWP) with large opacities.

METHODSSixty-two patients with CWP were examined with both chest radiograph and CT/HRCT scan. Comparison was done.

RESULTSLarge opacities were found in 19 patients in the chest radiograph of 62 patients with CWP. The detection rate was 30.6%. Thirty large opacities were found using chest radiograph. Forty-three patients with large opacities were found using the CT/HRCT. The detection rate was 69.4%. One hundred and twenty-three large opacities were found using CT/HRCT. Ninety-three more large opacities were found by CT/HRCT than by chest radiograph. The total detection rate of large opacities by CT was 4.1 times than by chest radiograph. Both differences were statistically significant (chi2 = 18.58, P < 0.01). CT/HRCT found all patients with large opacities detected in the chest radiograph. Seventeen patients with Stage III large opacities (>or= 1.0 cm x 2.0 cm) were found by the chest radiograph. The detection rate was 27.4% (17/62). Twenty-seven large opacities were found using chest radiograph. Thirty-four patients with Stage III large opacities were found using the CT/HRCT. The detection rate was 54.8%. The found Stage III large opacities added up to 67. The found Stage III large opacities by CT/HRCT were 40 more than using chest radiograph. Both differences were statistically significant (chi2 = 9.63, P < 0.01). CT/HRCT was reliable to show the morphology, the inside structure, the tiny lesion and the special location of the large opacities of CWP. It could provide more important information for differential diagnosis.

CONCLUSIONCT/HRCT is significantly better than the chest radiograph in the diagnosis of complicated CWP. It can find the large opacities that the chest radiograph can not. It has a great diagnostic and practical value as an assistant examination method. CT/HRCT could be considered as the reference and evidence for staging progression in diagnosis of pneumoconiosis.