Diagnostic imaging modalities in the study of hepatic alveolar echinococcosis: A review of literature

Objective: This review article aims to summarize the main imaging modalities employed in the diagnosis of hepatic alveolar echinococcosis (HAE) and provide radiologists with an overview of the most relevant diagnostic approaches. Methods: A literature review was conducted, selecting the most relevant articles from the past 5–10 years. The search was performed in PubMed, MDPI, Scopus, Web of Science eLIBRARY.RU, using the keywords alveococcosis, hepatic alveolar echinococcosis, echinococcus multilocularis, liver, metastasis, USG, CT, MRI, positron-emission tomography, imaging, diagnosis. Illustrative materials presented in the article originate from the authors' personal archive. Results: Hepatic alveolar echinococcosis (HAE) is a chronic parasitic disease characterized by an infiltrative growth pattern, often mimicking malignant liver tumors. Its ability to invade adjacent structures and disseminate to distant organs necessitates a comprehensive imaging approach for accurate diagnosis and staging. Ultrasound (US) serves as the primary screening tool for HAE, particularly in remote endemic regions where advanced imaging modalities may be unavailable. Its accessibility and real-time imaging capabilities allow for the initial detection of hepatic lesions. However, due to its limited ability to assess vascular and biliary involvement, further imaging is required for precise disease evaluation. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) are the cornerstone imaging techniques for assessing both hepatic and extrahepatic disease extension. CT provides detailed anatomical visualization of the liver parenchyma and is essential for evaluating lesion size, vascular encroachment, and potential metastatic spread. MRI, particularly magnetic resonance cholangiopancreatography (MRCP), is superior in delineating biliary tree involvement, facilitating preoperative planning and surgical decision-making. To standardize disease staging, the World Health Organization (WHO) has introduced the PNM classification system, which parallels the oncological TNM framework. This classification system enables a systematic assessment of the parasite burden within the liver (P), its invasion of adjacent structures (N), and the presence of distant metastases (M), thereby guiding therapeutic strategies. Conclusion: Radiologists should be aware of the specific imaging features of HAE to avoid misdiagnosis as a malignancy. A multimodal imaging approach is recommended to ensure accurate diagnosis and staging.