Magnetization transfer contrast imaging of liver cirrhosis

To test the feasibility of magnetization transfer contrast (MTC) imaging in the evaluation of liver cirrhosis.

Three normal volunteers and 22 cirrhotic liver patients (13 of them harbored hepatoma) were prospectively studied with on-resonance binomial pulsed MTC imaging using a 1.0 Tesla MR scanner. Both MTC and non-MTC images were acquired. The magnetization transfer (MT) effect (defined as: 1-signal intensity of MTC/signal intensity of non-MTC), was used as an indicator and was correlated with different disease status. Lesion-to-liver contrast of non-MTC versus MTC imaging was also compared.

Chronic hepatitis and early fibrosis had a MT effect similar to that of the normal group. Frank cirrhosis had the strongest MT effect. Cirrhosis, when infiltrated by diffuse hepatoma, showed a significantly weaker MT effect than that of the normal group (p<0.05), early cirrhosis (P<0.005), and frank cirrhosis (p<0.05). Overall, the MT effects in these 22 patients were widely variable. There was no significant improvement in lesion contrast of MTC imaging when compared to that of non-MTC imaging due to complex signal attenuation behavior of either the background liver tissue or the tumor itself.

The complex pathological change of the cirrhotic liver tissue may account for the wide variation of the MT effect and the compromised lesion contrast in cirrhotic patients. Caution should be taken when cirrhotic tissue has an unusually weak MT effect. Then, the possibility of a mixed disease process such as fatty metamorphosis or diffuse hepatoma should be highly suspected. Our experience shows that MTC imaging plays a potential role in the evaluation of the multi-facets of cirrhotic tissue change.