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MRI signal characteristics of progressive massive fibrosis in silicosis
S Matsumoto1, H Mori, H Miyake
1Department of Radiology, Oita Medical University, Hasamamachi, Japan.
Aim:
To determine the magnetic resonance imaging (MRI) signal characteristics of progressive massive fibrosis (PMF) in silicosis.
Subjects And Methods:
We evaluated prospectively the MR appearances in 17 patients with 34 PMF lesions on the basis of pre-contrast signal intensity (SI) and SI pattern and post-contrast enhancement pattern, using a 0.5-T unit. There were 13 PMF lesions in six patients who had silicosis and 21 PMF lesions in 11 patients who had silicotuberculosis. The SI pattern on T2-weighted image (WI) was classified into four types and the pattern of contrast enhancement on T1-WI was classified into three types. MR appearances of PMF lesions were correlated with the findings of computed tomography (CT).
Results:
The commonest signal intensity characteristic was isointensity (70%) on T1-WI and hypointensity (68%) on T2-WI when compared with skeletal muscle. For signal pattern on T2-WI, a type with only internal high SI areas (46% in silicosis group, 38% in silicotuberculosis group) was most frequent. All of these areas corresponded to the low density areas at CT, suggestive of necrosis. After intravenous contrast medium enhancement, rim enhancement (54% in silicosis group, 52% in silicotuberculosis group) was most frequent, followed by no enhancement.
Conclusion:
The most common MRI appearance of PMF was isointensity on T1-WI and hypointensity on T2-WI when compared with skeletal muscle, with internal high SI areas on T2-WI and either rim enhancement or no enhancement.
Insights
Magnetic resonance imaging (MRI) reveals progressive massive fibrosis (PMF) in silicosis typically appears isointense on T1-weighted images and hypointense on T2-weighted images. Internal high signal areas on T2-weighted images and rim enhancement are common findings.
Area of Science:
- Radiology
- Pulmonary Medicine
- Medical Imaging
Background:
- Progressive massive fibrosis (PMF) is a severe form of silicosis.
- Accurate imaging characteristics are crucial for diagnosis and management.
Purpose of the Study:
- To characterize the magnetic resonance imaging (MRI) signal features of PMF in silicosis.
- To correlate MRI findings with computed tomography (CT) in patients with silicosis and silicotuberculosis.
Main Methods:
- Prospective evaluation of 34 PMF lesions in 17 patients using a 0.5-T MRI unit.
- Analysis of pre-contrast signal intensity (SI) and SI patterns on T1- and T2-weighted images (WI).
- Assessment of post-contrast enhancement patterns and correlation with CT findings.
Main Results:
- Isointensity on T1-WI (70%) and hypointensity on T2-WI (68%) were the most common signal characteristics compared to skeletal muscle.
- A T2-WI signal pattern with internal high SI areas was frequent (46% silicosis, 38% silicotuberculosis), correlating with CT-suggestive necrosis.
- Rim enhancement (54% silicosis, 52% silicotuberculosis) or no enhancement was observed post-contrast.
Conclusions:
- The typical MRI appearance of PMF includes isointensity on T1-WI and hypointensity on T2-WI.
- Internal high SI areas on T2-WI and rim or no enhancement post-contrast are characteristic findings.
- MRI provides valuable insights into the imaging features of PMF in silicosis.
