ECR 2019 / C-1176
Hydatid Disease in Different Organs, A Pictorial Review
Type:
Educational Exhibit
Keywords:
Parasites, Diagnostic procedure, Ultrasound, MR, CT, Liver, Extremities, Abdomen
Authors:
A. Al-Taie, Z. AHMED, Z. Jaleel; Doha/QA
DOI:
10.26044/ecr2019/C-1176
Findings and procedure details
1.
Plain Radiograph:
- Rim-like calcification in soft tissues and abdominal viscera.
- Fairly homogenous opacity with or without calcification in Lungs.
2.
Ultrasound:
First ultrasound classification developed by Gharbi et al.
in 1981 consists of five stages:
- Stage 1: Homogeneously hypoechogenic cystic thin-walled lesion.
- Stage 2: Septated cystic lesion.
- Stage 3: Cystic lesion with daughter lesions and floating membranes.
- Stage 4: Pseudo-tumor lesion.
- Stage 5: Calcified or partially calcified lesion (inactive cyst).
3.
CT scan:
- The cysts demonstrate fluid attenuation (0 - 30 HU).
- The daughter vesicles usually contain fluid with a lower attenuation than that of the fluid in the mother cyst.
- Cyst calcification usually occurs in the cyst wall and is curvilinear or ring like.
- During the natural course of hydatidosis complete calcification occurs.
- Death of the parasite is implied by complete calcification.
- The cysts may also demonstrate septations and floating membranes,
honeycomb pattern or water lily sign.
- Contrast enhanced CT may be required when complications (such as infection and communication with the biliary tree) are suspected.
4.
MRI:
- On MRI,
simple cysts display high signal intensity on T2-weighted and low signal intensity on T1-weighted images and have well-defined margins.
- The internal architecture of the daughter cysts,
floating membranes and septations are well demonstrated.
- Diffusion-weighted sequence is important in differentiating liver hydatid cysts from other simple cysts.