Can Cirrhosis and Chronic Hepatosplenic Schistosomiasis Be Differentiated on MRI?

The objective of a recent study was to determine if there are useful features on MRI to help differentiate between alcoholic or viral cirrhosis and chronic.

The study has concluded that presence of peripheral periportal fibrosis, heterogeneous hepatic parenchyma, and splenic siderotic nodules, and the splenic index and caudate lobe-right lobe ratio, are useful features for differentiating alcoholic- or virus-induced cirrhosis from chronic hepatosplenic schistosomiasis.

Participants/Methodology
Twenty-seven patients with cirrhosis and 24 patients with chronic hepatosplenic schistosomiasis were evaluated in this retrospective analysis. MR examinations were performed utilizing a 1.5-Tesla system. MR sequences included T1-weighted in-phase and opposed-phase gradient echo sequences, T2-weighted sequences with and without fat suppression, and dynamic in-phase gradient echo images prior to and following dynamic intravenous administration of gadolinium contrast.

Two abdominal radiologists reviewed the images for hepatic and splenic changes. Hepatic changes included widening of fissures, periportal fibrosis, parenchymal heterogeneity, irregular hepatic contour, and splenic siderotic nodules. The following measurements were also recorded: caudate lobe-right lobe ratio, antero-posterior diameter of the left lobe, and the splenic index.

Results of the Study
Features favoring hepatosplenic schistosomiasis over cirrhosis included heterogeneous hepatic parenchyma, splenic siderotic nodules, and peripheral periportal fibrosis. Periportal fibrosis was found to have a peripheral distribution in patients with schistosomiasis as opposed to a central distribution in patients with cirrhosis.

The caudate lobe-right lobe ratio and splenic index were larger in schistosomiasis patients. Caudate lobe-right lobe ratio >1.5 is rarely found in patients with cirrhosis. However, this ratio is not based on a difference in caudate lobe size, but on the difference in size of the right hepatic lobe.

There was a discrepancy found in right hepatic lobe size, with schistosomiasis patients having a significantly smaller right hepatic lobe. There was a 94% sensitivity and 84% specificity in detecting schistosomiasis in patients with a splenic index >=1197 cm3. Splenic siderotic nodules were found in close to 65% of patients with schistosomiasis, as opposed to close to 4% in patients with cirrhosis.

However, this finding should not be used in isolation when trying to distinguish between these two patient populations, as other studies report considerable variability in the presence of splenic siderotic nodules in cirrhotic patients.

Conclusions
Presence of peripheral periportal fibrosis, heterogeneous hepatic parenchyma, and splenic siderotic nodules, and the splenic index and caudate lobe-right lobe ratio are useful features for differentiating alcoholic- or virus-induced cirrhosis from chronic schistosomiasis using MRI.

Reviewer’s Comments
The results of this study demonstrate certain morphologic changes that could favor a diagnosis of chronic hepatosplenic schistosomiasis rather than viral or alcoholic-induced cirrhosis. These clues can help one consider this parasitic infection as a possible cause for the patient’s hepatic and splenic findings, rather than simply attributing them to the easier diagnosis of cirrhosis. Making such a distinction is also important for treatment.

One of the limitations reported in this study was a small sample population size.

Author: John C. Sabatino, MD, MSD

Reference
Bezerra AS, D’Ippolito G, et al. Differentiating Cirrhosis and Chronic Hepatosplenic Schistosomiasis Using MRI. AJR Am J Roentgenol; 2008; 190 (March): W201-W207.