MR Differentiation of Lung Cancer from Progressive Massive Fibrosis in Patients with Coal Worker's Pneumoconiosis

To analyze the potential of MR to distinguish lung cancer from progressive massive fibrosis (PMF) in patients with coal worker's pneumoconiosis. The study consisted of 9 patients with pathologically proven lung cancer and 26 PMFs in 17 patients. All the patients had radiologic evidence of pneumoconiosis. T1-weighted FLASH images were obtained before and 0.5, 1, 2, 3, 4, 5, 7.5, 10, 12.5, and 15 minutes after injection of Gd-DTPA. T2-weighted fast spin-echo images were obtained. The imaging findings were evaluated for enhancement time curve, contrast uptake equivalent (CE), and enhancement factor (EF). On T1WI, there was no significant signal intensity difference between lung cancer and PMF. On T2WI, all lung cancer showed high signal intensity, as opposed to all PMFs which showed low signal intensity except for one PMF. Only one PMF showed high signal intensity on T2WI. For the dynamic contrast study, lung cancer showed faster and slightly stronger enhancement than PMFs. For a delayed image, most of the lung cancers (78%) showed washout, as opposed to a plateau in most of PMFs (73%) (p=0.0153). However, no difference was detected between the EFmax of lung cancer and PMFs (p=0.349). MR is potentially a useful tool in distinguishing lung cancer from PMFs in patients with coal worker's pneumoconiosis