MRI of tuberculous pyomyositis

Purpose: The purpose of this article is to describe the findings of MRI in tuberculous pyomyositis (PM). Method: The MR images of four proven cases of tuberculous PM were retrospectively reviewed and analyzed with clinical and laboratory findings. The location, signal intensity on T1- and T2-weighted spin echo images, presence of abscess, signal intensity of peripheral rim, patterns of contrast enhancement, and associated findings were evaluated. Results: On MR images, all cases demonstrated low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in a single muscle. Abscess was seen in all cases. Peripheral rim showed subtle hyperintensity on T1-weighted images and hypointensity on T2-weighted images. After gadolinium infusion, peripheral rim enhancement was observed in all cases. Cellulitis was associated in one case. The patients clinically presented with a palpable mass of long duration. Conclusion: Tuberculous PM shows characteristic findings of a well demarcated abscess with rim enhancement at MRI and can be distinguished from other soft tissue masses.