Imaging Aspects of Hepatic Alveolar Echinococcosis: Retrospective Findings of a Surgical Center in Turkey

Abstract

Radiologists should be aware of the findings of alveolar echinococcosis (AE) due to the diagnostic and management value of imaging. We are attempting to define the most common diagnostic imaging findings of liver AE, along with the prevalence and distribution of those findings. The patients' US, CT, and MRI images were reviewed retrospectively. CT images were acquired with and without the administration of contrast medium. The MRI protocol includes T2-weighted images (WI), diffusion (WI), apparent diffusion coefficient (ADC) maps, and pre- and post-contrast T1WIs. The current study included 61 patients. The mean age of the population was 58.2 ± 9.6 years According to Kratzer's categorization (US), 139 lesions (73.1%) were categorized as hailstorm. According to Graeter's classification (CT), 139 (73.1%) lesions were type 1-diffuse infiltrating. The most frequent types were Kodama type 2 and 3 lesions (MRI) (42.6% and 48.7%, accordingly). P2N0M0 was the most frequent subtype. The current study defines the major, characteristic imaging findings of liver AE using US, CT, and MRI. Since US, CT, and MRI have all been utilized to diagnose AE, we believe that a multi-modality classification system is needed. The study's findings may aid radiologists in accurately and timely diagnosing liver AE.

Keywords: CT; MRI; US; alveolar echinococcosis; imaging.

Figure 1

58-year-old female. Hepatic lesion with irregular margins, calcifications (circle), and large cystic-necrotic component (N) are seen.

Figure 2

51-year-old male. Hepatic lesion with irregular contours and calcifications on precontrast axial CT (A). On portal venous images (B), no enhancement is present in the lesion. Central necrosis can be seen (A,B—black star). Perilesional enhancement (B—white star) and capsular (A,B—arrows) retraction are present.

Figure 3

53-year-old female. Hepatic lesion with irregular borders and calcification (A,B—arrows) on precontrast axial CT (A). On portal venous images (B), no enhancement is present in the lesion. Central necrosis can be seen (B—black star). Perilesional enhancement (B—white star) is present.

Figure 4

67-year-old male, axial T2WI (A), axial postcontrast T1WI (B), axial DWI (C), and axial ADC map (D). Hepatic lesion with irregular borders (A, arrows) and other hepatic homogeneous T2 hyperintense lesions (A, circle). Central necrosis was present (A,B, stars), no contrast enhancement is seen (B). Lesions were slightly hyperintense on DWI and slightly hypointense on ADC map. Mean ADC value of the large lesion was 1.58 × 10⁻³ mm²/s, while the smaller ones were 1.44 × 10⁻³ mm²/s and 1.42 × 10⁻³ mm²/s.