Stage-Oriented CT Classification and Intermodal Evolution Model in Hepatic Alveolar Echinococcosis

Abstract

Background Alveolar echinococcosis (AE) is one of the most dangerous human parasitoses. The main site of disease manifestation is the liver (about 98 %). The Echinococcus Multilocularis Ulm Classification for Computed Tomography (EMUC-CT), presented in 2016, was the first compilation of CT morphological criteria of hepatic AE. Studies based on EMUC-CT made it possible to draw conclusions about the development of the lesions in the course of disease beyond purely diagnostic typing. Among the most important findings of these precursor studies was that EMUC-CT type IV presented as an initial lesion, whereas EMUC-CT type III lesions were mostly associated with an advanced disease constellation. An intermodal view of image morphological criteria provides further multi-layered indications for lesion evolution. Method With the “Alveolar Echinococcosis Ulm Classification” (AEUC), a revision of the previous EMUC-CT was carried out with stage-oriented reorganization of the primary morphologies. Furthermore, an intermodal classification scheme for the evolution of hepatic AE lesions based on AEUC, MRI Kodama classification, and aspects of ultrasound could be outlined. Results The first stage-oriented CT classification of hepatic AE “AEUC” is based with respect to its lesion characterization on the separate consideration of two classification pillars, the five “primary morphologies”, AEUC I–V (AEUC II–IV with subcriteria) and the five “patterns of calcification”. In addition, an intermodal classification scheme presents five stages of lesion evolution: “initial stage”, “progressive stage”, “advanced stage”, “transitional stage” and “regressive stage”. Conclusion The imaging modalities differ with respect to their visualization of lesion criteria. This underlines the need for unimodal classification systems. Staging of an AE lesion can be done more accurately by evaluating different modalities. Key Points: Citation Format

Differentiation of hepatic alveolar echinococcosis with a hemangioma-like pattern compared to typical liver hemangioma using contrast-enhanced ultrasound: a pilot study

“…However, such comparative studies are currently lacking. In addition to EMUC-US, classification systems currently exist for MRI and CT [12,13]. In 2015, Azizi et al correlated MR tomographic AE lesions classified by Kodama with [18F] FDG uptake on PET-CT and demonstrated increased PET activity for type I-III microcysts [29].…”

“…A total of five following different patterns are distinguished: hailstorm, pseudocystic, hemangioma-like, metastasis-like and ossification [10]. CT and MRI are additional methods that can be used in the diagnosis of hepatic AE [11][12][13]. However, PET-CT and PET-MRI are the only methods used to assess the parasitic activity of AE lesions [14,15].…”

Echinococcoses – A Primer for Radiologists

“…AE does not develop in stages directly comparable to CE. However, a connection between the image properties and temporal evolution of AE manifestations is postulated (see below) [30]. Abortive AE with spontaneous inactivation is possible [31].…”

SOP Echinokokkose

“…Die aktuell zur Verfügung stehende CT-Klassifika-tion ist vor allem für wissenschaftliche Fragestellungen geeignet. Größere prospektive Studien hierzu liegen bisher nicht vor [9].…”

“…Auch hier stehen Klassifikationsschemata zur Einordnung der Befunde für Ultraschall, CT und MRT zur Verfügung (s. Abb. 6 ) 8 , 9 , 10 . Die Bildgebung ist heutzutage der Schlüssel zur Diagnose der Echinokokkose.…”