Table 1 Imaging modalities, indications, advantages and disadvantages in AE and CE
From: Role of the radiologist in the diagnosis and management of the two forms of hepatic echinococcosis
| Â | When to use | Â | Â | Â |
|---|---|---|---|---|
| Â | Alveolar echinococcosis | Cystic echinococcosis | Advantages | Disadvantages |
US | Diagnosis  Incidental diagnosis (Heterogeneous echogenic liver lesion)  Follow-up (screening for biliary dilatation or vascular involvement) | Diagnosis  Reference for early diagnosis in endemic areas  Modality of choice for evaluation of WHO-IWG classification (Internal matrix visualization) | Low cost Availability Radiation free | Operator dependant Limited by body habitus No exhaustive study Lack of extension assessment |
CEUS | Diagnosis  Confirm absence of enhancement of echogenic liver lesion in case of fortuitous discovery | No indication | Safety | Requires experience |
CT | Diagnosis/follow-up  Detail number, size and location of AE lesions Preoperative imaging:  Assessment of hilar extension to vascular and biliary structures  Peripheral contacts (diaphragm, pericardium, peritoneum) | Diagnosis/follow-up  Not suitable for staging the disease  Modality of choice to detect complications (rupture of CE lesions)  Work-up of patients (look for lesions of lung and peritoneum) | Availability Spatial resolution that enables precise preoperative work-up (exploration of the entire peritoneal cavity ± chest | Radiation exposure Requires intravenous contrast injection (usefulness limited in allergic patients, chronic kidney disease) |
MRI | Diagnosis/follow-up  Modality of choice for positive diagnosis (pathognomonic microcyst)  Essential in uncertain cases (non-calcified lesions++)  Modality of choice for biliary structure extension assessment  Parasitic activity assessment (microcyst in T2 / restricted diffusion in DWI) | Diagnosis/follow-up  Modality of choice for biliary complications  After US screening: complete locoregional extension assessment  Internal matrix characterization if calcified lesion on US | Radiation free Detailed imaging with qualitative and quantitative analysis | Time of examination Availability |
FDG-PET | Diagnosis/follow-up  Modality of choice to assess disease activity (Peripheral hypermetabolism, Delayed acquisition+++)  Monitoring of parasitic activity | No indication | Easily readable | Radiation exposure Availability Limited to the assessment of parasitic activity |