MR characteristics of progressive massive fibrosis

This study was performed to evaluate the static and dynamic magnetic resona nce imaging (MRI) contrast enhancement pattern of progressive massive fibro sis (PMF) in coal workers' pneumoconiosis. Eighteen lesions in 12 patients were evaluated using a 1.5-T MR unit. T1-weighted FLASH images were obtaine d before and 0.5, 1, 2, 3, 4, 5, 7.5, 10, 12.5, and 15 minutes after inject ion of gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA; 0.1 mmol/k g). Imaging findings, che contrast enhancing pattern, enhancement time curv e, and the contrast uptake equivalent (CE; mmol/L) mere evaluated. On T1-we ighted images, 14 lesions showed high signal intensity, and four showed low signal intensity. On T2-weighted images, all lesions were of low signal in tensity and were indistinguishable from aerated lung parenchyma. After cont rast infusion, all lesions except two enhanced markedly. The time enhanceme nt curve showed a marked, gradual increase in signal intensity up to 3 minu tes, a subtle increase in signal intensity up to 7.5 minutes, and then a pl ateau until 15 minutes after Gd-DTPA injection, Characteristic MR findings of PMF in coal workers' pneumoconiosis include T1 high signal intensity, T2 low signal intensity, and marked postinfusion enhancement. The time enhanc ement curve shows a marked, gradual increase of signal intensity up to 3 mi nutes and plateau up to 15 minutes.