Cholangiohepatitis: Radiological spectrum of the disease amid the rising prevalence in India: A case study in a tertiary institute in South India

Sonali Dattatray Prabhu; Dattatray A Prabhu; Sandeep N. R Gopal Krishna; Ashwini Kumar; Santosh P. V Rai; Ajit R Mahale

doi:10.4103/jdmimsu.jdmimsu_34_17

ORIGINAL ARTICLE

Year : 2017 | Volume : 12 | Issue : 4 | Page : 261-268

Cholangiohepatitis: Radiological spectrum of the disease amid the rising prevalence in India: A case study in a tertiary institute in South India

Sonali Dattatray Prabhu¹, Dattatray A Prabhu², Sandeep N. R Gopal Krishna³, Ashwini Kumar¹, Santosh P. V Rai¹, Ajit R Mahale¹
¹ Department of Radiodiagnosis, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education (MAHE), Karnataka, India
² Department of Anaesthesia, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education (MAHE), Karnataka, India
³ Department of Gastroenterology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education (MAHE), Karnataka, India

Date of Web Publication

17-May-2018

Correspondence Address:
Dr. Sonali Dattatray Prabhu
Department of Radiodiagnosis, Kasturba Medical College, Mangalore, Manipal Academy of Higher education (MAHE), Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jdmimsu.jdmimsu_34_17

Abstract

Introduction: There is a rising incidence of Oriental cholangiohepatitis (OCH) also known as recurrent pyogenic cholangitis (RPC), in Indian population. The condition which presents with classical triad of recurrent upper abdominal pain, obstructive jaundice and fever is characterized by biliary sludge, intrahepatic bile duct calculi, strictures, duct dilatation and cholangitis resulting from chronic biliary parasitic infestation and associated chronic secondary portal bacteremia. Aim: The purpose of this retrospective study was to understand the spectrum of radiological manifestations of oriental cholangiohepatitis by MRI which helps in differentiating it from other differential causes of biliary obstruction and cholangitis. Materials and Methods: This was a retrospective study of cases of oriental pyogenic cholangitis diagnosed by MRI over a period of 3 years in department of radio diagnosis who were referred from gastroenterology department with clinical suspicion of cholangitis and diagnosed as having OCH based on MRI finding's and later confirmed by ERCP or biochemical parameters. Results: Out of the total 950 MRCP scans evaluated, 150 cases were of suspected cholangitis and only 9 cases had features of oriental pyogenic cholangitis. These patients showed the characteristic MRCP finding's like ductal changes including intraductal calculi with dilatation and strictures in RHD and LHD, segmental and subsegmental IHBRs and in extrahepatic biliary tree i.e. CHD and CBD with decreased arborization of peripheral biliary radicals; wall thickening in biliary tree and pneumobilia; and parenchymal abnormalities like fatty liver, hepatomegaly, segmental atrophy or diffuse liver atrophy. Complications like portal hypertension, splenomegaly and ascites that occur were also observed. Though literature mentions complications like hepatic mass/SOL i.e. hepatic abscess or malignancy, we didn't have any in our case series. Conclusion: To summarise, presence of hepatolithiasis and choledocholithiasis with significant biliary duct dilatation and short segment strictures in the biliary tree with peripheral IHBR pruning, usually in the absence of gallstones on MRCP is nearly pathognomonic of oriental pyogenic cholangitis in patients presenting with classical clinical triad of abdominal pain, jaundice and fever and obviates the need for diagnostic ERCP.

Keywords: Biliary obstruction, cholangitis, hepatolithiasis, oriental cholangiohepatitis, recurrent pyogenic cholangitis

How to cite this article:
Prabhu SD, Prabhu DA, Gopal Krishna SN, Kumar A, Rai SP, Mahale AR. Cholangiohepatitis: Radiological spectrum of the disease amid the rising prevalence in India: A case study in a tertiary institute in South India. J Datta Meghe Inst Med Sci Univ 2017;12:261-8

How to cite this URL:
Prabhu SD, Prabhu DA, Gopal Krishna SN, Kumar A, Rai SP, Mahale AR. Cholangiohepatitis: Radiological spectrum of the disease amid the rising prevalence in India: A case study in a tertiary institute in South India. J Datta Meghe Inst Med Sci Univ [serial online] 2017 [cited 2023 Nov 29];12:261-8. Available from: https://journals.lww.com/dmms/pages/default.aspx/text.asp?2017/12/4/261/232582

Introduction

Oriental cholangiohepatitis (OCH) is an infective-inflammatory condition caused by parasitic infestation of biliary tree leading to inflammation in the walls of the biliary tree with resultant fibrosis, strictures, duct dilatation, and intraductal calculi. This condition, first described in 1954 in Hong Kong, is seen commonly in Hong Kong, Taiwan, South China, Korea, and South East Asia and is also known as “Asiatic or Oriental cholangiohepatitis or cholangitis.”^[1] The condition is more commonly known as recurrent pyogenic cholangitis (RPC) as it presents as a triad of recurrent abdominal pain, jaundice, and fever. As intrahepatic ductal calculi are the classical features of the disease, it is also known as primary hepatolithiasis. The incidence of this condition is increasing in the Indian population as the most common causative organism ascaris lumbricoides is highly prevalent in India and mainly in the south Indian states as they are closer to tropics. It is documented that in the tropical regions up to 70% of the children are found to be infected by ascariasis.^[1]

With the current revolutionary advances in magnetic resonance imaging (MRI) technology and current magnetic resonance cholangiopancreatography (MRCP) protocols using rapid techniques that achieve image acquisition in a single breath-hold, MRCP is proving to be the gold standard and most preferred modality to evaluate a patient presenting with triad of abdominal pain, jaundice and fever to rule out OCH. In addition, MRCP also allows detailed and explicit anatomic evaluation of the location, extent, and severity of the disease, thus providing crucial data for further management and treatment of the disease. The purpose of this study was to understand the spectrum of radiological manifestations of OCH by MRI which help in differentiating MRI features of OCH from other differential diagnosis of biliary obstruction and cholangitis.

Materials and Methods

This was a retrospective study of cases of oriental pyogenic cholangitis diagnosed over a period of 3 years in the Department of Radiodiagnosis from January 2014 to January 2017 who were referred from gastroenterology department with clinical suspicion of cholangitis and diagnosed as having OCH based on MRI findings and later confirmed by endoscopic retrograde cholangiopancreatography (ERCP) or biochemical parameters.

All patients had undergone MRCP with a 1.5 Tesla Siemens MRI scanner. MRCP protocol included axial T2-weighted half fourier acquisition single-shot turbo-spin echo sequence, coronal T2-true fast imaging with steady-state free precession sequence, transverse T2-BLADE sequence (Siemens nomenclature for periodically rotated overlapping parallel lines with enhanced reconstruction–PROPELLER sequence), axial fat saturated gradient T1-VIBE (volumetric interpolated breath-hold examination) sequence, and three-dimensional (3D) respiratory-triggered heavily T2-weighted single slab fast spin echo (SPACE) sequence in the coronal oblique plane. From the 3D volume database, maximum intensity projection reconstructions were also obtained in coronal and sagittal planes over 180°array as well as thick slab and volume rendered reconstructions were obtained. In addition, wherever required postcontrast fat saturated T1 VIBE sequences were performed.

All MRI images were reviewed by radiologists with over 5 years of experience and MRCP findings were evaluated for parenchymal and ductal abnormalities. Parenchymal changes included liver size evaluation-enlargement or volume loss and signal intensity alterations and presence of mass lesions such as hepatic abscess or malignancy. Ductal analysis included the presence of duct dilatation of intrahepatic and/or extrahepatic ducts and arborization of peripheral segmental biliary radicals; presence of strictures, intraductal calculi in intrahepatic ducts and/or extrahepatic biliary tree, pneumobilia, wall thickening in biliary tree. The presence of gallbladder calculi and secondary changes of cirrhosis, portal hypertension, splenomegaly, and ascites was also noted.

Results

Out of the total 950 MRCP scans studied, around 150 cases were suspected cholangitis with abdominal pain, and jaundice but there were only 9 cases of oriental pyogenic cholangitis identified (as seen in [Table 1]). All of these patients had presented with pain, jaundice, and history of recurrent bouts of intermittent fever. One of the patients was a known case of OCH diagnosed by MRCP in another institute and now had come for follow-up imaging. Another female patient underwent MRI scanning twice over 1 year interval due to progressive disease but eventually succumbed to sepsis and multiorgan failure.

Table 1: Reveals magnetic resonance imaging findings in 9 patients with oriental cholangiohepatitis

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There were 7 cases in females and 2 in males. The patients were aged from 21 to 56 years, with mean age of 38.

Ductal abnormalities

Duct dilatation

Intrahepatic segmental or subsegmental duct dilatation [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5] was seen on MRCP in all 9 patients caused due to obstruction by either stricture or impacted stones with abrupt tapering and decreased arborization of the peripheral intrahepatic biliary radicals (IHBRs). Duct dilatation was further classified as mild, moderate, and severe. Mild duct dilatation was seen in two cases, moderate in five cases, and severe in two cases. Isolated involvement of the left hepatic duct and left lobar IHBRs only was seen in two cases [Figure 2]. Extrahepatic duct dilatation involving common hepatic duct (CHD) and common bile duct (CBD) was seen in 9 cases of which minimal to mild dilatation was seen in 3 cases. Characteristically, these three cases which had minimal dilatation [Figure 2] also showed the absence of intraductal calculi and strictures in the CBD and CHD.

Figure 1: (a-f) reveals the radiological spectrum of oriental cholangiohepatitis in MRI imaging. A - Axial T2 image, B, C & E- coronal T2 images, D- heavily T2 weighted thin slab MRCP image and F- coronal MIP MRCP image. Note the multiple calculi (white arrow) in the intrahepatic as well as extrahepatic biliary tree, intrahepatic strictures (blue arrow) and dilatation in the intrahepatic ducts (orange arrow) and biliary radicals with peripheral pruning (green arrow). Stricture in the CBD is also evident (yellow arrow) with dilatation of the biliary tree

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Figure 2: MRI images in a 40 year old female patient of OCH presenting with recurrent pain, jaundice and fever demonstrates the characteristics OCH features. A & E- MRCP thin slab coronal images, B- axial T2 image, C- MRCP 3D MIP image, D- coronal T2 image and F- 3D volume rendered MIP MRCP image. Note the intrahepatic calculi (white arrows) and multiple short segment intrahepatic strictures and moderate to severe duct dilatation (red arrows) of IHBRs with decreased peripheral arborization. Also noted is splenomegaly (figure 2B)

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Figure 3: MRI images in a 21 year old male OCH patient. A to C - coronal T2 images, D & E- axial T2 images, F- MRCP thin slab image. Multiple intrahepatic calculi and moderate duct dilatation (red arrows) is well seen with peripheral pruning and strictures (orange arrow) along with extrahepatic duct dilatation and calculi (white arrow). Hepatomegaly and focal fatty infiltration in the right lobe are also seen (green arrow). Note the absence of gall bladder calculi (blue arrow). Also evident is gross splenomegaly (purple arrow) and ascites (dotted black arrow)

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Figure 4: MRI images in a 38 year old female OCH patient showing left lobe and extrahepatic biliary tree involvement sparing the right lobe. A & B- T2 coronal images, C & D- axial T2 images, E- thick slab MRCP image and F- MRCP MIP image. Note multiple intrahepatic calculi, strictures and severe duct dilatation (yellow arrows) in the left hepatic lobe with marked peripheral pruning and uninvolved right lobe; dilatation and calculi in the CHD and CBD (red arrows), enlarged right lobe (dotted black arrow) with severe atrophy of the left lobe (blue arrow) and splenomegaly (purple arrow)

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Figure 5: (a-f) MRCP MIP reconstruction images in 6 cases of OCH patients demonstrating the classical spectrum of radiological manifestations. Figures demonstrates intrahepatic calculi and duct dilatation (red arrows) with peripheral pruning; intrahepatic duct strictures (yellow arrows); extrahepatic duct dilatation with calculi (blue arrow) and extrahepatic stricture in CBD (green arrow in figure B)

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Intraductal calculi

Calculi within the CHD and CBD were seen in 6 cases with dilatation seen involving ducts both proximal and distal to the calculi. Hepatolithiasis, i.e., calculi within the intrahepatic biliary tree involving RHD and LHD; their segmental and subsegmental branches were seen in all the 9 cases [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]. Involvement of both the right and left intrahepatic ducts was evident in 6 cases, and only in the left lobar intrahepatic ducts in 3 cases [Figure 2].

Biliary strictures

Multiple intrahepatic biliary strictures were seen in all 9 cases involving the main hepatic ducts, segmental and subsegmental ducts as well as other peripheral biliary radicals [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]. It was noted that except in 3 cases which showed preferential left lobar involvement, rest of the 6 cases had bilobar ductal strictures including RHD and LHD. Extrahepatic strictures were less common than intrahepatic strictures and more commonly affected CBD (3 cases) than CHD (2 cases). These strictures were short segment strictures <1 cm and were also associated with calculi. None of the cases showed only extrahepatic strictures in the absence of calculi.

Biliary wall thickening

Biliary walls thickening representing acute phase of cholangitis was seen in five cases with enhancement seen in both the two cases where contrast was administered. Pneumobilia was seen in one case.

Liver parenchymal abnormalities

Liver size

Parenchymal atrophy was evident in 5 cases with mostly segmental involvement; more commonly involving the left lobar segments II, III, and IV as seen in 4 cases with selective atrophy of right lobe in one case involving segments VI and VII. All the 9 cases showed liver enlargement either diffuse or compensatory segmental enlargement of caudate lobe, right or left lobe depending on the presence of associated segmental atrophy.

Parenchymal signal changes

Fatty infiltration was seen in 7 cases with hepatomegaly and diffuse fatty liver seen in 3 cases and focal fatty infiltration in 4 cases involving either both lobes (1 case), right lobe (2 cases) [Figure 3], or left lobe (1 case).

Presence of cholelithiasis

It was noted that most patients had absence of gallstones [Figure 1], [Figure 2], [Figure 3] except for three cases.

Secondary changes and complications

Portal hypertension was noted in 5 cases manifesting as portal vein dilatation (3 cases), splenomegaly (5 cases) [Figure 2], and ascites (5 cases) [Figure 2]. One patient was scanned twice with features of sepsis evident in the repeat scan done in 2016; 1 year after initial diagnosis and manifesting as acute cholangitis, portal hypertension, gross splenomegaly, and gross ascites. Subsequently, this patient required Intensive Care Unit (ICU) admission and intubation but later expired due to sepsis and multiorgan failure.

Unlike literature cases, none of our cases had intrahepatic abscesses or malignancy.

Discussion

OCH also known as RPC, oriental cholangitis, primary cholangitis, and intrahepatic pigment stone disease is characterized by biliary sludge, intrahepatic bile duct calculi, strictures, duct dilatation, and cholangitis due to chronic biliary parasitic infestation and associated chronic secondary portal bacteremia. Clinical manifestations include recurring episodes of upper abdominal pain, obstructive jaundice, and fever with chills.^[1],[2] It usually affects in the third and fourth decades of life with equal incidence seen in males and females.

Historical perspective

Digby in 1929–1930 had first reported the condition in 8 patients in Hong Kong. Himsworth proposed the name Cholangiohepatitis in 1947 for biliary infection resulting from obstruction of extrahepatic bile ducts due to impacted stone or malignancy. Stock and Tinckler had first researched its treatment. Clinical features were first described by Cook in 1954 who proposed that suppurative cholangitis is precursor of intrahepatic stone formation and that the stones might be of aseptic origin and described its association with Clonorchis sinensis infestation.^[3]

Etiopathogenesis

Although the precise causative factor is unknown, strong associations exist between OCH and parasites such as Ascaris lumbricoides and Clonorchis sinensis; and also with Escherichia ^{More Details} coli cholangitis. OCH is more prevalent in population of low socioeconomic status with nutritional deficiency.^[1],[4] RPC and ascariasis have similar geographical distribution and around 5% of hepatobiliary ascariasis can develop OCH after 2 or more years. Conversely, 10% of RPC may have clinicopathological evidence of ascariasis.^[1]

Parasitic infection causing inflammation in biliary walls starts a cascade of pathognomonic changes causing fibrosis and strictures in biliary tree with resultant ductal dilatation. Biliary sludge and calculi occur in dilated intra- and extra-hepatic biliary tree. Hepatolithiasis is the striking feature seen in OCH in over 90% cases. The biliary calculi in RPC are pigment stones with layers of bilirubinates and cholesterol deposited on top of a nidus which in 72% of cases may be a residue of Ascaris worm. Biliary sludge is a consequence of biliary wall damage by biliary ascariasis. Only 15% can have cholecystolithiasis in gallbladder.^[1]

Periductal inflammation and fibrosis induce thickening of periportal spaces leading to single or multiple biliary strictures. Biliary duct dilatation occurring due to loss of duct wall elasticity is disproportionate with more extensive involvement of the extrahepatic and central intrahepatic ducts, with little or no dilatation of the more peripheral biliary ducts. In fact, there is decreased branching, i.e., decreased arborization of peripheral ducts with abrupt tapering due to stenosis. All segments of biliary tree may be involved, but the lateral segment of the left lobe is most often and extensively involved.^[4] Extrahepatic duct dilatation is diffuse, can occur both proximal and distal to stone unrelated to its location. However, localized dilatation of the intrahepatic bile ducts is closely related to the site of stricture and impacted stone, especially the lateral segmental ducts of the left hepatic lobe.^[5]

There is a severe distortion of biliary ducts with recurrent cholangitis episodes being self-perpetuating in the absence of active ascariasis. Recurrent cholangitis leads to biliary strictures and hepatic abscess formation.^[1],[5] Recurrent biliary sepsis may be compounded by papillitis and Sphincter of Oddi ^{More Details} motor dysfunction due to mechanical injury to the papilla caused by the roundworm invasion. Pneumobilia is commonly seen in OCH due to patulous ampulla consequent to calculi passage.

Over a period of time, all these changes can cause hepatic parenchymal atrophy and scarring leading to cirrhosis and portal hypertension.

Clinical manifestations and course

OCH has a chronic progressive course; with repeated acute exacerbations characterized by cholangitis and sepsis with eventual bad prognosis.

Complications of oriental pyogenic cholangitis

Parenchymal liver disease and cirrhosis due to scarring
Hepatic abscess can occur due to secondary bacterial infection in 20% patients and involve right lobe more often. Multiple and multiseptated abscesses with thick walls are seen and needs to be differentiated from biloma
Bilomas are intrahepatic bile lakes with or without communication with the biliary tree with thin imperceptible walls and may contain calculi. Extrahepatic biloma is relatively rare and occurs due to leakage of intrahepatic bile from a severely dilated obstructed duct
Portal vein thrombosis can occur due to intimal fibrosis caused by inflammatory changes in the adjacent periportal spaces or as a complication of cirrhosis
Malignancy – Exact cause for increased risk of cholangiocarcinoma in OCH, which can occur in 5% cases, is not known but may be secondary to chronic bacterial infection, bile stasis, or mechanical irritation by calculi and more commonly affects atrophied hepatic segments or segments with a heavy stone burden. Cholangiocarcinoma compounding OCH has a poor prognosis due to delay in diagnosis caused by misinterpretation of the underlying OCH changes. Hepatocellular carcinoma (HCC) can also occur with increased frequency in OCH patients, due to development of cirrhosis in severe cases.^[1],[4],[5]

Diagnosis

Laboratory investigations

Blood tests reveal leukocytosis, with increased count of polymorphonuclear leukocytes and mildly elevated bilirubin. Elevated levels of alkaline phosphatase and excretion of urobilinogen in urine are evident. Bile cultures may yield E. coli or other enteric bacteria.^[5]

Imaging

Conventional radiography and contrast study

Role of conventional techniques is absolute in the present era of cross-sectional imaging. Moreover, plain radiography has no role in diagnosis as the stones are seldom radiopaque.^[5]

T-tube cholangiogram will reveal a dilated CBD. However, diagnostic accuracy is limited due to:

Easy passage of iodinated contrast into duodenum in these patients due to patulous ampulla of Vater obscuring field of view; and
Dysfunction of sphincter of Oddi allowing reflux of ingested air from the duodenum into the CBD causing pneumobilia which can be misinterpreted as intrahepatic calculi as both cause filling defects thus limiting diagnostic accuracy.^[6]

As the OCH affects intrahepatic ducts more than the common hepatic and CBDs, cholecystography offers hardly any information. Oral cholecystography demonstrates poor function or non-visualization of the gallbladder. Intravenous cholangiography is also an inefficient modality as it may fail to delineate and opacify the biliary tree due to dilution of contrast in severely dilated ducts thus requiring larger doses and higher radiation parameters.^[6]

Ultrasonography

It is the baseline investigation in OCH and shows dilatation of the biliary tree with increased periportal echogenicity. Detection of calculi depends on size, echogenicity, shadowing characteristics, and location of the stones. Calculi may have varying echogenicity - isoechoic to echogenic appearance with/without shadowing depending on whether they are calcified or not. Hypoechoic intra- and extrahepatic calculi may not cause shadow and are missed on ultrasonography (USG), thus underestimating the number. Furthermore, pneumobilia which is common in OCH can obscure and misdiagnose the number of calculi. Biliary mud or sludge which is isoechoic may fill the dilated ducts limiting detection of intrahepatic ductal dilatation.^[5] Biloma or abscess may be present and seen as hypoechoic or anechoic lesions. Malignant masses such as cholangiocarcinoma will have variable appearance: hypoechoic, isoechoic, or less commonly, hyperechoic compared to the hepatic parenchyma. USG-guided percutaneous aspiration or drainage of biloma or abscess; and fine-needle aspiration or core biopsy of suspected neoplasms can also be performed.^[4],[7]

Computed tomography

Computed tomography (CT) allows adequate delineation of the dilated extrahepatic and central intrahepatic first- and second-order ducts, with non-dilated or non-visualized peripheral ducts. Unenhanced CT easily detects 90% calculi as they are hyperdense compared to normal unenhanced liver parenchyma. However, CT also underestimates the number of calculi as not all are calcified. Contrast-enhanced CT may obscure calculi but allows better visualization of subtle intrahepatic duct dilatation.^[4] Extent and severity of strictures are well demonstrated, but strictures in OCH are usually short segment <1 cm and readily identified on CT due to partial volume averaging.^[5] CT allows detection of acute cholangitis seen as biliary wall thickening and enhancement, pneumobilia as well as complications of OCH such as hepatic parenchymal atrophy, hepatic abscesses, and malignant masses. Alterations in parenchymal attenuation may be seen either as fatty infiltration of atrophic or non-atrophic segments or heterogeneous parenchymal enhancement during acute phase of cholangiohepatitis.^[4]

Endoscopic retrograde cholangiopancreatography

ERCP was previously the gold standard for diagnosis, but due to advances in noninvasive diagnostic techniques like MRCP, indications for ERCP for diagnostic purpose only are waning unless simultaneous therapeutic procedures are being planned. Direct cholangiography reveals disproportionate extrahepatic duct dilatation, calculi, multiple intrahepatic strictures, and abrupt tapering of peripheral ducts with decreased arborization of the biliary tree. Advantages of ERCP over MRCP include better spatial resolution allowing better evaluation of peripheral ducts and allow therapeutic intervention at the same sitting. Disadvantages include invasiveness and high risk of septic shock, despite the use of prior IV antibiotics administration; and hence, over-distension of the biliary tree during contrast injection should be avoided. A stricture or calculus completely occluding duct lumen of the segmental or subsegmental bile ducts can prevent opacification of proximal bile ducts causing misinterpretation and missing diagnosis of upstream strictures or calculus.^[4],[5]

Magnetic resonance cholangiopancreatography

With revolutionary changes in MRI data acquisition and processing techniques, fast and accurate multiplanar cross-sectional images can be obtained in a single breath-hold MRI sequences. Better spatial resolution, parallel imaging techniques and 3D sequences are possible in the currently used respiratory-triggered MRI protocols. MRCP allows detailed delineation of the duct condition even proximal to an obstruction or tight stenosis allows visualization of both intra- and extra-ductal disease and can reveal complete extent, severity, and complications of the disease. Even noncalcified calculi are well demonstrated on MRCP as filling defects unlike CT or USG. However, differentiating them from pneumobilia may sometimes be difficult. However, calculi are seen in dependent location in bile ducts and air bubbles in nondependent location. MRI demonstrates central and extrahepatic duct dilatation with decreased arborization and abrupt tapering of peripheral ducts. MRI particularly MRCP sequences accurately depicts stenotic segments and delineates the entire biliary tree, including the proximal part of the stricture, without risk of aggravating biliary sepsis. Even short segment duct strictures <1 cm are easily seen on MRCP.^[4] Wall thickening and enhancement is seen in acute cholangitis. MRCP can reveal 100% of surgically proven dilated ducts, 96% of focal strictures, and 98% of calculi.^[8] Parenchymal abnormalities like hepatic atrophy whether diffuse or segmental are seen as variable signal intensities, i.e., hypo-, iso-, or hyperintense to normal liver on T1 images and iso- or hyperintense on T2 images with segmental volume loss and crowding of dilated ducts. Mass lesions and hepatic abscesses if present are also well delineated.^[4],[8]

Imaging of oriental cholangiohepatitis complications

Hepatic abscesses needs to be differentiated from biloma. Multiseptated appearance with peripheral and rim enhancement on CT and MRI is suggestive of hepatic abscess rather than biloma. In doubtful cases, USG-guided aspiration helps in diagnosis. Bilomas typically appear anechoic on sonography and uniformly hypodense on CT. Direct cholangiography can demonstrate communication of biloma with the biliary tree.

Cirrhosis, portal hypertension, and portal vein thrombosis can be diagnosed by sonography and cross-sectional imaging.

Cholangiocarcinoma complicating OCH can be either hilar or extrahepatic cholangiocarcinoma, seen as ill-defined lesion causing focal stenosis or obliteration of the involved duct with an enhancing area of focal wall thickening; or peripheral cholangiocarcinoma which appears as a low-density mass on CT and high-signal intensity lesion on MRI with a thin rim of contrast enhancement on CT and MRI. Hence, peripheral cholangiocarcinoma can mimic a hepatic abscess misleading the diagnosis and warranting fine-needle aspiration to differentiate benign pathology from cholangiocarcinoma. Diffusion-weighted MRI increases detection of malignant liver lesion as on T2 sequence both abscess and mass both show heterogeneous T2 hyperintensity. Imaging appearance of HCC occurring in OCH patients is similar to HCC occurring in other causes of cirrhosis.^[4],[5]

Differential diagnosis

Biliary obstruction by gallbladder calculi or benign biliary strictures – usually dilatation will be seen only proximal to obstruction with absence of hepatolithiasis
Caroli's disease – saccular segmental dilatation of IHBRs with biliary stasis, cholangitis, liver abscess, and stone formation however extrahepatic involvement is rare
Primary sclerosing cholangitis – thickening of biliary walls with characteristic “beaded” appearance seen due to strictures and dilatation with the absence of hepatolithiasis
Biliary obstruction to malignant tumors – cholangiocarcinoma, carcinoma of ampulla of Vater or pancreatic head – dilatation of upstream biliary tree is seen and the malignant mass will be demonstrated on cross-sectional imaging.^[5]

Treatment

Due to the chronicity and complexity of the condition and non-availability of a single effective treatment, multidisciplinary management is required by a team of radiologists, surgeons, gastroenterologists, intensivists, and interventional radiologists with the aim of eliminating all biliary calculi and achieving biliary drainage by treating biliary strictures to prevent recurrent cholangitis and hepatolithiasis and providing adequate supportive management of cholangitis and sepsis in the acute phase by providing ICU care. In the past, surgery was the preferred treatment modality wherein hepatic segment was resected with biliary-enteric anastomosis for bile drainage. However, surgery is effective only when disease involves isolated hepatic segment. Surgical resection is often not possible as disease is more extensive or due to secondary liver cirrhosis. Due to better availability of endoscopic instruments, catheters, and devices, more aggressive endoscopic approach is possible and alternative treatment modalities are replacing surgery for intrahepatic stones and biliary stenoses; such as flexible choledochoscopy, endoscopic papillotomy, repetitive dilatations of the stenosis, and clearance of calculi by forceps lithotripsy, basketing, or balloon sweeping. With recent advances in the field of interventional radiology, use of percutaneous biliary procedures and stenting is increasing. During acute phase, biliary decompression by a percutaneous catheter helps. Percutaneous calculi removal with a steerable catheter by basketing, balloon dilatation of stricture, and insertion of biliary endoprostheses and stents including expandable metallic stents has shown promising results. Despite aggressive treatment, however, there is a high recurrence rate of calculi and strictures.^[5],[9]

Conclusion

Multiple intraductal calculi in the intra- and extrahepatic biliary tree with significant duct dilatation and short segment strictures in the extra- and intrahepatic first and second order ducts with peripheral IHBR pruning, usually in the absence of gallstones on MRCP is nearly pathognomonic of OCH in patients presenting with classical clinical triad of abdominal pain, jaundice and fever. MRCP thus helps to establish the diagnosis and obviated the need of ERCP minimizing risk of biliary sepsis. We are presenting our experience of the radiological spectrum of MRCP findings in 9 patients of OCH with review of literature to emphasize the need for correct diagnosis and differentiating this condition from other causes of cholangitis.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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