Figure 11a.

Synergy of SPIO and a gadolinium-based contrast agent for direct visualization of advanced fibrosis in a man with HCV-related cirrhosis. Axial unenhanced (a), gadolinium-enhanced (b), SPIO-enhanced (c), and double contrast-enhanced (SPIO plus gadolinium) (d) 2D T1-weighted (repetition time = 150 msec, flip angle = 70°) and T2*-weighted (echo time = 6 msec) gradient-echo images, obtained at 3 T within a 1-week period, show a cirrhotic liver with innumerable hyperintense reticulations surrounding hypointense regenerative nodules. Parenchymal alterations are poorly demonstrated on the unenhanced image. Gadolinium-based contrast agent accumulates in extracellular spaces within fibrotic tissue and enhances the signal of fibrotic reticulations. Iron oxides selectively accumulate within Kupffer cells and darken the background parenchyma. In combination, SPIO and a gadolinium-based contrast agent are synergistic and depict fibrotic reticulations (arrows in d) and regenerative nodules (arrowheads in d) with high clarity on the double contrast-enhanced image.