Purpose: The objective of this study was to identify the factors affecting the visualization of regenerating nodules in cirrhotic liver by MR imaging.
Material and methods: MR images from patients with liver cirrhosis and normal subjects were studied, and signal intensity within the liver was measured and correlated with histologic findings. A reference phantom was also used as a standard.
Results: The signal intensity of the liver on T2-weighted (T2WI) spin-echo (SE) images was significantly increased in patients with liver cirrhosis. Multiple ring-like or reticular high-intensity areas (RHAs) were demonstrated on T2WI SE images in 44 of 125 cirrhotic livers. Histologic examination in 44 cases revealed various degrees of inflammatory changes in fibrous septa surrounding regenerative nodules in all specimens, vascular dilation in fibrous septa in 4 specimens, and no hemosiderin deposition in some specimens. The results of linear discriminant analysis showed that inflammatory changes in fibrous septa were significantly more pronounced in cases with RHAs on MR.
Conclusion: RHAs seen on T2WI SE images may correspond to fibrous septa with inflammation. The signal intensity of fibrous septa surrounding regenerative nodules on T2WI SE images may be increased in liver cirrhosis due to inflammation or vascular dilation, contributing to the visualization of regenerating nodules as relatively low-intensity regions on MR.