**3.5 Imaging modalities**

There are many available imaging modalities that are helpful in visualizing and evaluating the biliary system. Noninvasive imaging modalities can demonstrate common nonspecific findings of EC such as bile duct wall thickening (segmental or diffuse) on US (see **Figure 2**) and contrast enhanced CT and MRCP with or

#### **Figure 2.**

*This contrast enhanced ultrasound (CEUS) shows thickened wall of intrahepatic bile ducts (from hilar to peripheral) with dilation, and the lesion was well enhanced.*

#### **Figure 3.**

*(a) Computed tomography scan (CT scan) of abdomen and pelvis; (b) magnetic resonance cholangiopancreatography (MRCP); (c) endoscopic retrograde cholangiopancreatography showing a focal dilation of the biliary tree to the left lobe through the suggestion of subtle ill-defined enhancing mass lesion at the level of liver hilum.*

**177**

**Figure 4.**

*cholangiocarcinoma.*

*Eosinophilic Cholangitis*

cholangiocarcinoma.

many eosinophils.

**3.6 Proposed diagnostic criteria**

*DOI: http://dx.doi.org/10.5772/intechopen.86004*

performing invasive imaging modalities such as ERCP.

ducts as well as the length and site of biliary stricture.

ERCP with brush biopsy may not show malignant cells.

most of the time, the index of suspicion for malignancy remains high.

without biliary dilation (see **Figure 3**). These findings can also be seen in malignant processes, hence the need to obtain a brush cytology and tissue biopsy by means of

While MRCP is useful in demonstrating an irregular narrowing of the bile duct, ERCP and percutaneous transhepatic cholangiography (PTC) provide additional information such as irregularities of the common bile duct and the intrahepatic

ERCP with brush biopsy, PET-CT (see **Figure 4**) and an endoscopic guided fine needle aspiration (EUS guided FNA) are also used to try to differentiate a benign from a malignant cause of biliary tree dilation. As you can see, the CT scan shows an ill-defined enhancing mass lesion at the level of liver hilum suggesting

EUS-guided FNA may show a background of mixed inflammation including

Matsumoto et al. revealed a characteristic feature of EC that helped rule out malignancy: staining of a parenchymal echo in the bile duct wall on

*This positron emission tomography-computed tomography (PET-CT) reveals a soft tissue lesion within the main left biliary duct but does not show any fluorodeoxyglucose (FDG) activity. This still does not exclude* 

Sometimes the diagnosis can be made, and targeted treatment can be started but

#### *Eosinophilic Cholangitis DOI: http://dx.doi.org/10.5772/intechopen.86004*

*Cells of the Immune System*

biliary tree.

**3.5 Imaging modalities**

○ ALP and GGT are usually increased like any other diseases involving the

○ Since eosinophilic cholangitis can mimic cholangiocarcinoma, tumors

Again, looking at the laboratory investigation, it is still hard to pinpoint the

There are many available imaging modalities that are helpful in visualizing and evaluating the biliary system. Noninvasive imaging modalities can demonstrate common nonspecific findings of EC such as bile duct wall thickening (segmental or diffuse) on US (see **Figure 2**) and contrast enhanced CT and MRCP with or

*This contrast enhanced ultrasound (CEUS) shows thickened wall of intrahepatic bile ducts (from hilar to* 

*(a) Computed tomography scan (CT scan) of abdomen and pelvis; (b) magnetic resonance* 

*cholangiopancreatography (MRCP); (c) endoscopic retrograde cholangiopancreatography showing a focal dilation of the biliary tree to the left lobe through the suggestion of subtle ill-defined enhancing mass lesion at* 

diagnosis, the next step would be to move on into imaging modalities.

markers such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) can be ordered and surprisingly may be elevated making the

○ Amylase and lipase to rule out a pancreatic cause.

diagnosis even more challenging.

*peripheral) with dilation, and the lesion was well enhanced.*

**176**

**Figure 3.**

*the level of liver hilum.*

**Figure 2.**

without biliary dilation (see **Figure 3**). These findings can also be seen in malignant processes, hence the need to obtain a brush cytology and tissue biopsy by means of performing invasive imaging modalities such as ERCP.

While MRCP is useful in demonstrating an irregular narrowing of the bile duct, ERCP and percutaneous transhepatic cholangiography (PTC) provide additional information such as irregularities of the common bile duct and the intrahepatic ducts as well as the length and site of biliary stricture.

ERCP with brush biopsy, PET-CT (see **Figure 4**) and an endoscopic guided fine needle aspiration (EUS guided FNA) are also used to try to differentiate a benign from a malignant cause of biliary tree dilation. As you can see, the CT scan shows an ill-defined enhancing mass lesion at the level of liver hilum suggesting cholangiocarcinoma.

ERCP with brush biopsy may not show malignant cells.

EUS-guided FNA may show a background of mixed inflammation including many eosinophils.

Sometimes the diagnosis can be made, and targeted treatment can be started but most of the time, the index of suspicion for malignancy remains high.
