**4.2 Imaging**

In 1981, Gharbi reported an ultrasonography classification of the hepatic hydatidosis, describing five categories in relation to the morphological findings of the cysts, according to their stage of evolution [28]. In 2002, based on this classification, the World Health Organization Informal Working Group on Echinococcosis (WHO-IWGE) formulated a new classification adding two more categories, with the aim of guiding in the selection of the best treatment and follow-up of the results obtained (**Tables 1** and **2**) [29–31]. Current imaging offers several tools to


**153**

**Figure 2.**

*Cyst of solid appearance (CE4).*

*4.2.1 Ultrasonography*

**Table 2.**

*Surgical Treatment of Hepatic Hydatidosis DOI: http://dx.doi.org/10.5772/intechopen.86319*

**therapy**

CE1 ✓ ✓ <5 cm ABZ PAIR

CE2 ✓ ✓ ✓ Other PT + ALB

CE3a ✓ ✓ Other PT < 5 cm

CE3b ✓ ✓ ✓ Non-PAIR PT + ABZ

*Suggested stage-specific approach to uncomplicated cystic echinococcosis of the liver.*

**WHO Surgery PAIR Drug** 

guide a better management of this disease. Usually, the imaging diagnostic begins with the use of ultrasonography (US), and then other imaging tests could also be used to achieve a better diagnosis of the most complex forms of parasitosis, such as contrast-enhanced ultrasound (CEUS), computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangiography (MRC), endo-

CE4 Watch and wait Optimal CE5 Watch and wait Optimal

PAIR

PAIR

ABZ PAIR

Other PT

Non-PAIR PT

>5 cm PAIR+ALB

ABZ PAIR >5cmPAIR+

**Suggestion Resource setting**

Optimal Minimal Optimal Minimal

Optimal Minimal

Optimal Minimal Optimal Minimal

Optimal Minimal

The US is widely used due to its low cost and high-definition images, which allow to define the pathological characteristics of hepatic hydatid cysts and other locations in the peritoneal cavity (**Figures 2**–**4**). It is also useful for the differential diagnosis of hydatid cyst with other liver tumors. The use of mobile devices allows having a portable tool for the screening of populations in endemic

scopic retrograde cholangiography (ERC), and conventional X-rays.

**Table 1.** *WHO-IWGE ultrasound classification.* *Surgical Treatment of Hepatic Hydatidosis DOI: http://dx.doi.org/10.5772/intechopen.86319*


#### **Table 2.**

*Liver Disease and Surgery*

**4.1 Clinical features**

**4.2 Imaging**

**4. Diagnosis**

**152**

**Table 1.**

**WHO-IWGE Radiologic characteristics Definition of cyst**

In 1981, Gharbi reported an ultrasonography classification of the hepatic hydatidosis, describing five categories in relation to the morphological findings of the cysts, according to their stage of evolution [28]. In 2002, based on this classification, the World Health Organization Informal Working Group on Echinococcosis (WHO-IWGE) formulated a new classification adding two more categories, with the aim of guiding in the selection of the best treatment and follow-up of the results obtained (**Tables 1** and **2**) [29–31]. Current imaging offers several tools to

Currently, the diagnosis must always consider the epidemiological background. The definitive diagnosis is reached through the use of imaging and in some cases with the additional contribution of serology. In the near future, earlier stages of the parasitosis will be diagnosed by means of advances in immunological tests [24, 25].

Humans remain asymptomatic for a prolonged period of time after being infected due to the slow growth of the hydatid cyst in the liver (1–5 mm per year). Small and medium cysts of central hepatic location are usually asymptomatic, or a slight pain in the epigastrium and right hypochondrium might be reported by the patient, together with a sensation of abdominal discomfort. Besides, the previous immune status of the patient and the anatomical location of the cyst could determine a late manifestation of the first symptoms [26]. When the cysts grow and reach a significant size, the mass effect on the bile tree and hepatic vasculature determine other clinical manifestations derived from biliary obstruction, portal hypertension, and Budd-Chiari syndrome. The magnitude of this effect will determine different degrees of jaundice and portal hypertension, which may range from a slight increase of bilirubinemia and the appearance of venous collaterals of the abdominal wall to very severe jaundice, ascites, and upper digestive hemorrhage

Cystic lesion

Active cyst

Active cyst

Transitional cyst

Inactive cyst

Inactive cyst

CL Unilocular cystic lesion with uniform anechoic content, cyst wall not

secondary to rupture of the gastroesophageal varices [27].

CE1 Unilocular cystic lesion with uniform anechoic content, cyst wall visible,

CE2 Multivesicular, multiseptated cysts, daughter cysts present, honeycomb

CE3A Unilocular cyst containing liquid with a floating membrane inside,

CE4 Cysts with heterogeneous hypoechoic or hyperechoic degenerative

CE5 Cysts characterized by a thick calcified wall, which is arch shaped,

producing a cone-shaped shadow; degree of calcification varies from

visible

sign

*WHO-IWGE ultrasound classification.*

snowflake sign

water-lily sign

CE3B Cysts with daughter cysts in solid matrix

partial to complete

contents, no daughter cysts

*Suggested stage-specific approach to uncomplicated cystic echinococcosis of the liver.*

guide a better management of this disease. Usually, the imaging diagnostic begins with the use of ultrasonography (US), and then other imaging tests could also be used to achieve a better diagnosis of the most complex forms of parasitosis, such as contrast-enhanced ultrasound (CEUS), computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangiography (MRC), endoscopic retrograde cholangiography (ERC), and conventional X-rays.

#### *4.2.1 Ultrasonography*

The US is widely used due to its low cost and high-definition images, which allow to define the pathological characteristics of hepatic hydatid cysts and other locations in the peritoneal cavity (**Figures 2**–**4**). It is also useful for the differential diagnosis of hydatid cyst with other liver tumors. The use of mobile devices allows having a portable tool for the screening of populations in endemic

**Figure 2.** *Cyst of solid appearance (CE4).*

**Figure 3.** *Heterogeneous matrix. Ball of wool sign (CE4).*

**Figure 4.** *Calcified anterior wall of cyst. Arciform image (white arrow).*

areas with high risk of affectation [30, 32, 33]. Due to the difficult differentiation of certain forms of alveolar echinococcosis from other kinds of hepatic tumors, CEUS is being increasingly used in certain regions with endemic affectation of this pathology [34].
