|Year : 2016 | Volume
| Issue : 4 | Page : 443-450
Obstructive jaundice: Its etiological spectrum and radiological evaluation by magnetic resonance cholangiopancreatography
Ankur Attri, Ritu Dhawan Galhotra, Archana Ahluwalia, Kavita Saggar
Department of Radiodiagnosis, Dayanand Medical College and Hospital, Ludhiana, Punjab, India
|Date of Web Publication||12-Jul-2016|
Ritu Dhawan Galhotra
96 Lal Bagh, Near Rajguru Nagar, Post Office Threeke, Ludhiana, Punjab
Source of Support: None, Conflict of Interest: None
Background: Magnetic resonance cholangiopancreatography (MRCP) has reached a level of resolution and reliability where it may replace diagnostic endoscopic retrograde cholangiopancreatography. We studied the role of MRCP in adult patients with obstructive biliopathy to analyze its etiological spectrum and radiological findings. Materials and Methods: Total fifty patients referred for mrcp with a clinical diagnosis of obstructive jaundice were included in our study. Imaging findings were correlated with the final diagnosis made by histopathological or cytological findings and with the therapeutic outcome. Aim: To evaluate the role of MRCP in the determination of the etiological spectrum, to evaluate level and degree of biliary obstruction in cases of obstructive jaundice and to correlate findings on mrcp with surgical findings where possible. Results: Of fifty patients, 29 were benign lesions and 21 were malignant lesions. Among the benign lesions, 12 had choledocholithiasis and 16 had benign strictures. One case was of a choledochal cyst. Among the malignant lesions, 12 were gallbladder carcinoma, six were cholangiocarcinoma, two were periampullary carcinoma, and one was a case of metastatic deposit. The overall sensitivity of MRCP was 96.5%, specificity was 95.2%, and with an accuracy of 96% for benign lesions. The accuracy, sensitivity, and specificity of MRCP in the diagnosis of benign strictures was 92%, 93.7%, and 91.2%, for choledocholithiasis was 92%, 75%, and 97.3%, and for malignant lesions was 95.2, 96.5%, and 96%, respectively. Conclusion: MRCP is a relatively quick, accurate, and noninvasive imaging modality for the assessment of obstructive jaundice, in ruling out potentially correctable underlying cause.
Keywords: Benign stricture, choledocholithiasis, gallbladder carcinoma, magnetic resonance cholangiopancreatography
|How to cite this article:|
Attri A, Galhotra RD, Ahluwalia A, Saggar K. Obstructive jaundice: Its etiological spectrum and radiological evaluation by magnetic resonance cholangiopancreatography. Med J DY Patil Univ 2016;9:443-50
| Introduction|| |
Magnetic resonance cholangiopancreatography (MRCP) is an important noninvasive imaging investigation in the preoperative evaluation of patients with obstructive jaundice. Since its first clinical introduction, dated 1991, MRCP has proved to be a reliable technique in the evaluation of biliary and pancreatic duct obstruction. In the early phases of its clinical application, it was considered as a second level examination in the diagnostic workup of the obstructive jaundice, following percutaneous transhepatic cholangiography and endoscopic retrograde cholangiopancreatography (ERCP) which were considered as first level examinations. Since decades, this imaging technique has significantly increased its diagnostic role in the diagnosis of obstructive jaundice. MRCP nowadays is widely used as a primary noninvasive imaging modality in the diagnosis of obstructive jaundice. It plays a primary role in the workup and therapeutic operative planning of obstructive jaundice.
Heavily T2-weighted fat suppressed sequences are used to produce images, in which static fluid is hyperintense, and background signal is suppressed. These images are suitable for postprocessing into projection images that resemble direct cholangiogram produced by ERCP or percutaneous transhepatic cholangiopancreatography.
Among the imaging techniques currently advocated for evaluating the biliary tree and pancreas, sonography and computed tomography (CT) are the most frequently used techniques. However, in a significant number of patients, especially when choledocholithiasis, an inflammatory stenosis, a postoperative stricture or even in many cases of malignant obstruction, direct opacification of the biliary tree or of the pancreatic duct is usually required for diagnosis or for surgical planning. In such cases, heavily T2-weighted images can be used to outline the biliary tree and pancreatic duct without the use of any intravenous contrast medium, and it can also outline the system even proximal to the obstruction. Hence, mrcp has an edge over ultrasound or contrast-enhanced CT.
Although generally considered a safe procedure, ERCP has a morbidity and mortality rate of 7% and 1%, respectively. In addition, the technique is highly operator dependent with unsuccessful cannulation of the common bile ducts (CBDs) occurring in 3-9% of cases, limited or no opacification of ducts proximal to a severe or complete obstruction and requires routine sedation. Consequently, there may be a role for a noninvasive test that can be a substitute for diagnostic ERCP. It is in this respect that MRCP which depicts the biliary tree noninvasively and without the injection of contrast medium offers an advantage over ERCP.
| Materials and Methods|| |
This study was started after taking ethical clearance from the Institutional Ethical Committee and fifty patients with clinical suspicion of obstructive biliary disease (showing jaundice, pain abdomen, melena, and deranged liver function test) were included in this study. The magnetic resonance (mr) scan was done using Magnetom Avanto 18 Channel 1.5 Tesla Y Machine by Siemens India Pvt Ltd., in the Department of Radio Diagnosis and Imaging, DMC and Hospital, Ludhiana.
Magnetic resonance cholangiopancreatography protocol
Localizer (flash T1-weighted) was taken in the coronal and axial plane after proper positioning of the patient. The MRCP protocol consisted of axial MPRAGE T1-weighted (TE 322/TR 1530, average-2, flip angle-150), coronal T2-weighted HASTE (TE 120/TR 1100, average-1, flip angle-150), transverse T2-weighted HASTE (TE 119/TR 1100), and three-dimensional (3D) heavily T2-weighted SPACE sequence with respiratory triggering (TE 622/TR 1600, average-1, flip angle-180). A 3D image (thick maximum intensity projection [MIP]) was reconstructed to visualize the billiary and pancreatic duct in a 3D view. In addition, T2 thick slab sequences RARE (TE 752/TR 4500, average-1, flip angle-180) with a slice thickness of 50 mm was taken in positive and negative angulations along the pancreatic duct. Multiplanner reconstruction was done in a coronal, axial, and sagittal plane with a slice thickness of 1 mm. Thick MIP of 15 mm was done in the coronal plane.
MR imaging (MRI) diagnosis was subsequently correlated with histopathological or cytologic outcome. The data were recorded in a proforma and were analyzed using descriptive statistics.
| Results|| |
In our study, on fifty patients of obstructive jaundice, the most common presenting complaint was jaundice (82%) followed by vomiting (72%) [Table 1]. There was a male preponderance in this study with a male:female ratio of 1.2:1.
Pathologies involving the common hepatic duct (CHD) constituted the bulk of patients (24%) followed by involvement of both CHD and primary confluence (22% cases) as well as intrapancreatic part (22%) [Table 2].
|Table 2: Distribution of subjects according to level of obstruction on magnetic resonance cholangiopancreatography|
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Benign causes of obstruction included 58% (29/50) cases, and malignant cause of obstruction were 42% (21/50).
Of total 29 benign cases, the most common cause of obstruction was benign strictures (16 cases) [Figure 1]. The second common cause was choledocholithiasis which was seen in total 12 patients and of them there were three patients who had coexistent strictures of CBD. There also was one case of Mirizzi's syndrome [Table 3].
|Figure 1: (a) Coronal T2-weighted image and T2 HASTE image (b) Nonvisualization of primary confluence and common hepatic duct (arrow). Common bile duct is normal in caliber. (c) Dilated intrahepatic biliary radicals are also seen in T2-weighted axial image. In a 50-year-old female patient with obstructive jaundice after cholecystectomy|
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|Table 3: Distribution of subjects according to benign cause of obstruction|
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The most common site of benign stricture in our analysis was CHD, which constitutes (37.5%) cases of benign strictures and 50.0% of total pathologies [Table 4].
Of total 21 malignant causes of obstruction, (24%) were carcinoma gallbladder infiltrating into biliary system. Cholangiocarcinoma and periampullary carcinoma constituted 12% and 4%, respectively [Table 5].
|Table 5: Distribution of subjects according to malignant cause of obstruction|
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Lesions involving intrapancreatic CBD were mostly benign which constitutes 31.0% (nine cases) of total benign lesions and 81.8 % of total intrapancreatic lesions. Lesions involving CHD as the level of obstruction were of equal incidence among benign and malignant pathologies, i.e., six subjects in each group. The highest incidence of malignant lesions was seen involving both CHD and primary confluence which included 9 (42.8%) out of total 21 malignant cases and 81.8% total lesions at this level. Twenty-eight cases with benign pathology and twenty cases with malignant pathologies were accurately diagnosed on MRCP. The overall sensitivity of MRCP was 96.5%, specificity was 95.2%, and with an accuracy of 96% for benign lesions. The overall sensitivity of MRCP was 95.2%; specificity was 96.5% with an accuracy of 96% for malignant lesions [Table 6].
|Table 6: Distribution of subjects according to level of obstruction for benign and malignant cause and correlation with final diagnosis|
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| Discussion|| |
Obstructive jaundice is a common surgical problem that occurs when there is an obstruction to the passage of conjugated bilirubin from liver cells to intestine. In obstructive jaundice, early investigation to elucidate the precise etiology is of great importance because pathological changes (e.g., secondary biliary cirrhosis) can occur if the obstruction is unrelieved.
MR cholangiography has proved effective in demonstrating bile duct dilatation, strictures, and choledocholithiasis. This noninvasive imaging technique demonstrates the site of the stenosis, degree of proximal dilatation, presence and size of biliary stones, and associated findings such as intraductal tumor growth. In patients with malignant obstruction, conventional (cross-sectional) MRI is performed along with MR cholangiography to determine the size and define the margins of the tumor. These factors must be considered when assessing the resectability of a malignant lesion.
In the present study, there were fifty patients in the age group of 11-90 years with the mean age of 52.6 years. Majority of cases below the age of 50 years presented with benign lesions (1.8:1), whereas beyond 50 years of age the benign and malignant lesions had equal age distribution (1:1). The mean age of the patients with benign lesions was 50 years and for malignant lesions it was 56.6 years. This was consistent with the study by Hasan and Hosam in which the mean age of malignant lesions was 54 years.
The most common presenting complaints of the subjects in our study were jaundice (82%) and vomiting (72%), respectively, which is consistent with the study by Verma et al.
On MRCP, features of obstruction were found in 47 patients in the form of CBD or IHBR dilatation; none of the cases had isolated CBD dilatation. Isolated IHBR dilatation was found in 21 patients, and both CBD and IHBR dilatation were found in 26 patients.
In the present series, pathologies involving the CHD constituted the bulk with 24% of the total number of cases. This was in contrast to study done by Upadhyayaet al., in which most frequent level of obstruction was found to be intrapancreatic CBD followed by suprapancreatic CBD and CHD. In the present study, there were 12 cases of gallbladder carcinoma infiltrating CHD and primary confluence, six cases of postcholecystectomy strictures at the level of CHD, and four cases of cholangiocarcinoma involving CHD. The other causes involving CHD included inflammatory strictures and calculi.
The benign cause of obstruction constituted 58% (29/50), and malignant constituted 42% (21/50). However, in a study done by Siddique et al. majority of patients had malignant obstructive jaundice, i.e., 56.66% (34/60) while the benign lesions were seen in 43.33% (26/60).
Among the 21 cases of malignant causes of obstruction, 12 (24% of total cases and 57.1% of malignant cases) were carcinoma gallbladder infiltrating into biliary system which correlated with findings in previous study done by Sharma and Ahuja in which they found carcinoma gallbladder (28.7% of total cases) to be the most common cause of malignant obstruction [Figure 2].
|Figure 2: T2-weighted coronal (a) And axial (b) Images reveal hypointense mass lesion involving neck of gallbladder (white arrow) extending along cystic duct to infiltrate into common hepatic duct (thick white arrow) resulting in intrahepatic biliary radical dilatation. Primary confluence is spared. Coronal HASTE image (c) Reveals the similar findings. (Magnetic resonance cholangiopancreatography in a 64-year-old female with yellowish discoloration of skin, loss of appetite and weight)|
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In our study, cancer antigen (CA) 19-9 was found to be raised in 11 (78.5%) out of 13 cases of malignant lesions consistent with the study by Saluja et al. who showed that CA 19-9 levels were significantly higher in cases with malignant strictures.
In the present study, we were able to identify the level of obstruction in all fifty cases. ERCP or surgical findings were similar for the level of obstruction in 47 cases. ERCP was not successful in three cases due to technical issues. Thus, the overall diagnostic accuracy of MRCP for detection of the level of obstruction was 94%.
Some recent studies have reported the high accuracy of MRCP in detecting the level and cause of obstruction. Regan et al. demonstrated biliary dilatation in 100% cases and detected the level of obstruction in 87% cases. Magnuson et al. detected the level of obstruction in 24 and cause of obstruction in 21 of the 25 patients with a malignant cause of obstruction. Of 48 patients with a benign cause, they were able to detect 45. Georgopoulos et al. detected the level accurately in 13 (87%) of 15 patients with malignant obstruction. Adamek et al. reported that MRCP could identify the presence and level of biliary obstruction with a sensitivity of about 90% and a specificity reaching almost 100%.
In biliary obstruction, advantages of MRCP are mainly related to routine visualization of ducts above and below the obstruction with a consistent demonstration of intrahepatic biliary branches. Patients with high bile duct strictures and with biliary obstruction at multiple levels are best suited for MRCP. It is also useful in cases in which ERCP is incomplete or when cannulation of the bile duct is not possible because of technical difficulties or anatomic factors. Moreover, MRCP offers a physiologic evaluation of the bile ducts [Figure 3].
|Figure 3: T2-weighted (a) And HASTE (b) Coronal images reveals hypointense mass lesion (thin white arrow) involving primary confluence resulting in biliary obstruction. Distal common bile duct is normal in caliber (thick white arrow). The diagnosis of cholangiocarcinoma (Klatskin tumor) was made on histopathology. (Magnetic resonance cholangiopancreatography in 42-year-old male patient with jaundice and weight loss)|
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Benign causes of obstructive jaundice
Of 12 cases of choledocholithiasis, nine were accurately diagnosed on MRCP, one of which was diagnosed as Mirizzi's syndrome. One case was falsely diagnosed as choledocholithiasis on MRCP, and later on was found to have sludge on ERCP. Of the three cases that were diagnosed to have strictures on MRCP, two were found to have stones on ERCP and one had stricture co-existent with stone. Hence, the overall sensitivity of MRCP for diagnosing choledocholithiasis was 75%, specificity 97.3%, and accuracy 92% [Figure 4].
|Figure 4: T2-weighted axial (a) Image reveals hypointense focus suggestive of calculus (arrow) in the suprapancreatic common bile duct. Multiple calculi are also seen in gallbladder. HASTE coronal image (b) Reveals multiple calculi (arrows) in the suprapancreatic and intrapancreatic common bile duct resulting in obstructive biliopathy. (Magnetic resonance cholangiopancreatography in a 45-year-old male patient came with clinical features of obstructive jaundice)|
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MRCP is comparable with ERCP in the detection of choledocholithiasis and superior to CT or ultrasonography. Numerous studies have shown sensitivities of 81–100% and specificities of 85-100% for MRCP. Because of the very high signal-to-background ratio of bile, calculi are readily identified as dark filling defects within the high-signal-intensity fluid at MRCP. Calculi as small as 2 mm in diameter can be visualized, and the accuracy of stone detection is greater with single-shot fast spin-echo techniques because of the reduction of motion and susceptibility artifacts. Small calculi may not cause secondary dilatation of the ducts and are best seen on the axial images.
In benign strictures (n = 16)
Fifteen out of 16 cases of benign strictures were accurately diagnosed on MRCP. One case diagnosed as choledocholithiasis on MRCP was also found to have benign stricture along with stone on ERCP. One case with inflammatory stricture due to chronic pancreatitis was found to have calculus in intrapancreatic part of CBD on ERCP. One case diagnosed as postcholecystectomy stricture involving posterior division of the right hepatic duct was also found to have multiple calculi in the right hepatic duct and CBD, and yet one another case diagnosed as stricture on MRCP also had calculi on ERCP.
Three cases were falsely diagnosed as benign stricture on MRCP. Two of these cases were later found to have stones, and one case had sludge only on ERCP. The overall sensitivity of MRCP was 93.7%, specificity was 91.2%, and with an accuracy of 92% for benign strictures.
In a study by Obaidi et al., the sensitivity, specificity, negative predictive value, positive predictive value, and diagnostic accuracy for benign strictures were 100%, 98.5%, 100%, 91.6%, and 98.7%, respectively.
Verma et al. in their study found the sensitivity and specificity for diagnosing benign strictures to be 92.3% and 86%, respectively.
In malignant strictures (n = 21)
Twenty out of 21 cases of malignant strictures were accurately diagnosed on MRCP. One case diagnosed as sclerosing cholangitis on MRCP was also found to have malignancy on histopathology.
One case was falsely diagnosed as a malignant lesion on MRCP in periampullary location, later on, was found to be benign on histopathology.
Hence, the overall sensitivity of MRCP for malignant strictures was 95.2%, specificity 96.5%, and accuracy 96%.
The criteria for differentiation of benign and malignant strictures included an irregular margin, asymmetric dilatation of the biliary radicles, abrupt or gradual tapering of stricture, presence or absence of a mass, and length of the stricture. Malignant strictures are usually long as they have an infiltrative growth pattern, which spreads intramurally beneath the epithelial lining. They are irregular with an asymmetric dilatation because of the nature of involvement of the bile duct by the tumor. We found that presence of a mass, stricture with long length (3 cm vs. 1.2 cm), and an irregular margin and asymmetric dilatation of the bile ducts helped in making a diagnosis of a malignant stricture. Park et al. found stricture length (3 cm vs. 1.3 cm) with irregular margin and asymmetric narrowing of bile ducts to suggest a malignant etiology. Bain et al. found long stricture (3 cm vs. 0.8 cm) and the presence of intrahepatic duct dilatation (93% vs. 36%) to suggest a malignant etiology.
Gallbladder carcinoma (n = 12)
All the cases diagnosed as gallbladder cancer in this study were diagnosed as adenocarcinoma on histopathology.
Gallbladder carcinoma can manifest as a polypoid mass with an intraluminal component, a bulky exophytic mass, or a mass infiltrating liver parenchyma and occupying the gallbladder lumen.
In the present study, MRCP showed high sensitivity, specificity, and accuracy (100%) for all the cases of gallbladder cancer were causing obstructive jaundice.
Cholangiocarcinoma (n = 6)
Cholangiocarcinoma had equal incidence among male and female in the present study.
Anatomically, cholangiocarcinomas are classified into three broad groups:
- Perihilar; and
- Distal extrahepatic.,
Intrahepatic cholangiocarcinoma arises from small intrahepatic bile duct branches and invades adjacent liver parenchyma. Perihilar cholangiocarcinoma or Klatskin tumor is the most common type and accounts for 50-60% of tumors. The distal extrahepatic type includes tumors that arise from extrahepatic ducts from the level of the upper border of the pancreas to the ampulla of Vater. The intrahepatic and distal extrahepatic types comprise 20-25% of cholangiocarcinomas each.,
In the present study, total six cases of cholangiocarcinoma were seen. Three of these cases were involving perihilar region, one involving only CHD, and two cases were seen diffusely involving the biliary system.
Five out of six cases of cholangiocarcinoma were accurately diagnosed on MRCP. One case diagnosed as sclerosing cholangitis on MRCP was found to have cholangiocarcinoma on histopathology. The overall sensitivity was 83.3%, specificity was 100%, and accuracy was 98.0% for cases with cholangiocarcinoma on MRCP.
Periampullary adenocarcinoma (n = 2)
Biliary obstruction in the intrapancreatic segment of the CBD may be caused by pancreatic carcinoma, ampullary carcinoma, or pancreatitis. In the present study, all two cases of periampullary malignant lesion were diagnosed accurately on MRCP. One periampullary lesion was falsely diagnosed as malignant on MRCP which later on histopathology came out to be benign. Hence, overall sensitivity was 66.7%, specificity was 100%, and accuracy was 96% for cases with periampullary tumors.
To summarize that pathology involving the CHD constituted the bulk of patients (24%). Benign lesions constituted 58%, and malignant lesions constituted 42% of total cases. In cases with benign lesions, most common level of involvement was intrapancreatic CBD (9/28). The most common benign cause was strictures (16/29). The accuracy, sensitivity, and specificity of MRCP in the diagnosis of benign strictures were 92%, 93.7%, and 91.2%, respectively. The most common level of obstruction in malignant causes was both CHD and primary confluence (9/21). The sensitivity, specificity, and accuracy of MRCP in the diagnosis of malignant diseases were 95.2, 96.5%, and 96%, respectively.
| Conclusion|| |
Hence, MRCP is a useful noninvasive and essential method in the preoperative evaluation of patients with obstructive jaundice. It is the modality of choice for optimal characterization of the causative lesions in most of the cases of obstructive jaundice. It accurately demarcates the level of obstruction and therefore influences clinician's diagnosis and management plans.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]