Evaluation of intrahepatic manifestation and distant extrahepatic disease in alveolar echinococcosis

Table 1 Overview of the echinococcosis multilocularis Ulm classification for computed tomography

Primary morphology (Subcriteria)	Pattern of calcification
Type I, Diffuse infiltrating (with cystoid portion / without cystoid portion)	Without calcifications
Type II, Primarily circumscribed tumor-like (with cystoid portion / without cystoid portion)	With feathery calcifications
Type III, Primarily cystoid - intermediate (IIIa), widespread (IIIb) - (with more solid portions at the edge / without more solid portions at the edge)	With focal calcifications
	With diffuse calcifications
Type IV, Small-cystoid/metastasis-like	With calcifications primarily at the edge
Type V, Mainly calcified	With a central calcification

The two pillars of the classification (Primary morphology and Pattern of calcification) are considered separately in the first instance and then, in principle, can be freely combined. There are two exceptions: the pattern “with a central calcification” can occur only with type IV primary morphology, while type V is not further characterized by a specific pattern of calcification. The focus for further evaluations in this study was on the determination of the main pillar of the classification, the primary morphology.