diagnostic accuracy ct and ercp

8/4/2019 Diagnostic Accuracy Ct and Ercp

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ABSTRACT

DIAGNOSTIC ACCURACY OF COMPUTED TOMOGRAPHY (CT) IN

DETECTING THE CAUSE OF OBSTRUCTION IN BILIARY OBSTRUCTIVE

DISEASE COMPARATIVE EVALUATION WITH ENDOSCOPIC

RETROGRADE CHOLANGIOPANCREATOGRAPHY (ERCP)

Statement of the Problem

The study aims to assess the accuracy of CT in detecting the cause of

obstruction in biliary obstructive disease in comparison with ERCP. Specifically thestudy sought the answers to the following questions:

1. What is Computed tomography ?

2. What is endoscopic retrograde cholangiopancreatography?

3 .What is diagnostic accuracy of CT in detecting causes of biliary obstructive

disease compared with ERCP in terms of :

a. Sensitivity

b. Specificity

c. Detection accuracy

Methodology

The study employed semi-systematic literature review was employed in the

study. An electronic search was performed using a wide range of data base in order to

obtain the information for the progress of the study. Each study was carefully reviewed

for their content and relevance to present investigation.


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Summary of Findings

1.What is Computed Tomography (CT)

CT or computed tomography is a diagnostic imaging procedure that uses x-rays

to obtain cross-sectional images. It is a non-invasive procedure that aid in the correct

diagnosis of biliary obstructions among others. Among the risks in CT procedure to

patients are possible allergy from contrast agent used in some cases and lifetime

exposure to radiation adverse health effects like hair loss, skin injury among others.

2. What is Endoscopic retrograde cholangio pancreatography

(ERCP).

Endoscopic retrograde cholanagiopacreatography is both a diagnostic and

therapeutic tool. Endoscopic refers to a thin, flexible tube with a tiny video camera and

light at the end, while retrograde refers to the direction in which the endoscope is used

to inject a liquid enabling X-rays to be taken of the parts of the GI tract called the bile

duct system and pancreas. ERCP is an invasive diagnostic modality indicated in

detecting biliary obstructions.

3 .What is accuracy rate of CT in detecting causes of biliary obstructive disease

compared with ERCP ?

a. Sensitivity


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Except with two studies the sensitivity rate of ERCP is consistently higher

compared with that of CT rate in detecting obstructive jaundice, biliary strictures,

common bile duct stones, choledochal stones and pancreatitis.

b. Specificity

Studies have shown that ERCP is superior to CT specificity-wise in detecting

causes of obstruction biliary strictures, jaundice and common bile duct stones, but is

out-performed in one case that involves detection of pancreaticobiliary.

c. Detection Accuracy

In all biliary obstructions examined by four studies indicate that only choledochal

cysts, bile duct injury had CT in equal footing with ERCP. But detecting gallbladder

stones, intrahepatic bile duct stones except with 1 study; choledocholithaiasis,

pancreatobiliary tumor, gallbladder carcinoma; pancreatic head carcinoma, bile papilla

carcinoma and chronic pancreatic, CT remains inferior to ERCP.

Conclusions

1. Computed tomography is a non-invasive diagnostic imaging procedure that

aided diagnosis and detection of some biliary obstructions.

2. Endoscopic retrograde cholangiography is an invasive diagnostic imaging tool

and therapeutic instrument for diagnosing and detecting biliary obstruction.


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3. In comparison between CT and ERCP, CT has lower sensitivity rate

compared to ERCP in detecting biliary obstructions like choledochal stones, obstructive

jaundice, biliary strictures; common bile duct stones and biliary pancreatitis.

5. In terms of specificity ERCP is found superior among diagnostic imaging

modalities including CT. Only 1 studies had found out that CT has 100% specificity in

detecting pancreatico biliary as against 91.7% of ERCP . The rest the studies showed

that ERCP remains superior with CT in terms of specificity rate in detecting obstructive

jaundice, biliary strictures and common bile duct stones.

6. In terms of detection accuracy, studies reviewed indicated the consistently

high accuracy rates of ERCP over CT.

Recommendations

The researcher recommends local studies on the clinical values of different

diagnostic imaging tools in view of rising cases of obstructive biliary disease in the

country.


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CHAPTER I

THE PROBLEM AND ITS BACKGROUND

Introduction

In any type of disease exact diagnosis is essential for proper medical

management and treatment. This is very important especially when the presenting

symptoms need immediate attention and could endanger the life of the patient. There

are diseases that could not be detected or diagnosed by auscultation alone. Different

diagnostic imaging modalities are used for accurate diagnosis of diseases. These tools

are used in examining diseases in the internal organs.

Diagnostic imageological tools are either invasive or non-invasive types.

Sometimes both types are used when initial diagnosis is doubtful. These tools greatly

aid in the diagnosis of internal organs like the bile duct. Bile duct is any of a number of

long tube-like structures that carry bile. Bile is required for the digestion of foods is

excreted by the liver into passages carrying it toward the hepatic duct which joins with

the cystic duct to form the common bile duct that opens into the intestine. The biliary

tree is the whole network of various sized ducts branching through the liver

(www.wikipedia.com). Several problems and abnormalities can arise from the bile

ducts. There are many causes of biliary obstruction. In recent years saw a rapid and

continuous evolution in the diagnosis of biliary obstructive disease (Ferrari, 2005).

These tools include invasive and non-invasive types. These include traditional

methodologies such as ultrasonography (US); computed tomography (CT), endoscopic
http://www.wikipedia.com/http://www.wikipedia.com/


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retrograde cholangiopancreatography (ERCP), percutaneous transhepatic

cholangiography) magnetic resonance cholangiopancreatogaphy (MRCP) and other

modalities which are improvement of the existing ones.

In this study, the focus of interest lies between computed tomography (CT) and

endoscopic retrograde cholangiopancreatography (ERCP). The main objective of the

study is to assess the diagnostic accuracy of CT in detecting causes of biliary

obstructive disease compared with ERCP.

Conceptual Framework

Diagnostic tests and examinations are used to confirm, exclude or classify the

location, severity, size, shape or other clinically meaningful subgroups of disease in

order to guide treatment, indicate prognosis or monitor progress. These tests are also

indicated in cases when clinical history and examination provide insufficient information

to distinguish a disease/s from a set of candidate diseases (differential diagnoses) or to

plan management. The results of these tests may lead to a decision threshold for a

given diagnosis or it may lead to further testing. In the case of biliary obstruction,

clinical decision-making is particularly complex, due to the wide range of differential

diagnoses including pancreaticobiliary disease that may need to be considered and the

potentially high penalty of delayed treatment if the cause is not detected in a timely

fashion (MSAC,2005).

In making diagnosis concerning biliary obstructive disease, there are a number

of diagnostic modalities available that includes CT and ERCP. Determining the

outcomes of the results of these test predetermined the health outcomes. However,

the outcomes depends on the accuracy of the test results with reference to sensitivity,


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specificity, and accuracy of detection. In the study, rate of sensitivity, specificity, level of

detection are predictors of accuracy of diagnosis of causes of biliary obstruction.

Statement of the Problem

The study deals with an evaluation of diagnostic accuracy CT in detecting causes

of biliary obstructive disease in comparison with ERCP. Specifically, the study aims to

answer the following questions:

1. What is Computed tomography ?

2. What is endoscopic retrograde cholangiopancreatography?

3 .What is diagnostic accuracy of CT in detecting causes of biliary obstructive

disease compared with ERCP in terms of :

a. Sensitivity

b. Specificity

c. Detection accuracy

Significance of the Study

Accurate diagnosis is essential in making informed decisions about the therapy

and treatment of diseases. The cost of wrong diagnosis is very high and at extreme

fatal for the patients and devastating for the doctors and the institutions. In the case of

diagnosing biliary obstruction, several imaging tools or modalities are available to aid

the doctors to come up with the correct and accurate diagnosis. The results of the tests

predetermined the outcome of the treatment. Computed tomography and endoscopic


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retrograde cholangiopancreatography are but two of the diagnostic tools in detecting

biliary obstruction and causes. Understanding the clinical value of each type will

increase the readers knowledge and help doctors decide which of the two type will be

effective in making informed clinical decisions regarding the patients conditions which

ultimately benefit the patients. Hence, the significance of the study.

Definition of Terms

These terms are used in the study. For clarity and appreciation of the present

study, these terms are defined:

Computed Tomography (CT). In the study refers to both plain and improved

typed OF diagnostic imaging tool in detecting biliary

obstruction. It is a cross-sectional representation of anatomy that is constructed by a

computer from the signals generated by x-ray beams passing through the body from

different directions (MASC,2005).

Diagnostic accuracy. As used in the study refers to the correctness of the results

of the tests using CT and ERCP.

Endoscopic retrograde cholangiopancreatography (ERCP). It is another

diagnostic tool for detecting biliary obstruction. It is an invasive tool that can also be

used for therapeutic intervention (MASC,2005).

Negative predictive value. It refers to the proportion of patients with negative test

results who are correctly diagnosed (www.wikipedia.com).

Positive predictive value. Defined as proportion of patients with positive test

results who are correctly diagnosed (www.wikipedia.com).
http://www.wikipedia.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.wikipedia.com/


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Sensitivity. One of the predictors of diagnostic accuracy refers to how many

cases of a disease a particular test can find (Boring 1990).

Specificity. Another diagnostic accuracy predictors in the study, refers to how

accurately it diagnoses a particular disease without giving false positive results.


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CHAPTER II

REVIEW OF RELATED LITERATURE AND STUDIES

Related Literature

The following is extracted from an assessment report prepared by the Medical

Service Advisory Committee of Australia that is found relevant to the present study on

accuracy of detection of diagnostic imaging modalities such as computed tomography

(CT) and endoscopic retrograde cholangeopancreatography (ERCP).

Normal function of the bile ducts and pancreas

Bile is a liquid produced by the liver that contains bile salts, cholesterol, lipids and waste

products, such as the pigment bilirubin. It is needed for the digestion and absorption of

fats and fat-soluble vitamins. The normal function of the bile ducts is to transport bile

from the liver to the gallbladder, where it is stored and concentrated, and then it is

released into the duodenum where it aids digestion. The bile is transported from the

gallbladder to the duodenum via the common bile duct through the valvular opening of

the sphincter of Oddi at the ampulla of Vater. After eating, the entrance of fat or protein

into the small intestine triggers the secretion of a hormone called cholecystokinin, which

stimulates contraction of the gallbladder and the opening of the sphincter of Oddi so that

bile may pass into the duodenum.

The pancreas is a small gland that lies behind the stomach and is surrounded by

the intestines and liver. Normal function of the pancreas is essential for the production


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of hormones such as glucagon and insulin that are released into the blood stream to

regulate blood glucose levels as well as enzymes that are released into the duodenum

for digestion. The pancreas also produces digestive enzymes and these enter the

duodenum from the pancreatic duct via the Ampulla of Vater to aid digestion.

Diseases associated with obstruction of the bile or pancreatic ducts

Pancreaticobiliary diseases (not including patients with associated gallbladder

disease) accounted for 19,552 hospital separations in Australia over the 12-month

period from 2002-2003. As described on page 10, common clinical presentations where

MRCP may be indicated include patients with symptoms or signs due to biliary

obstruction as a result of bile duct stones or strictures due to cancer, inflammation or

other benign causes.

Surgical treatment for bile duct stones and localised benign strictures is often

curative. If untreated, biliary obstruction can lead to fulminant infection (cholangitis) and

death. Long-term obstruction can also lead to chronic liver disease.

Stones in the common bile duct

Common presenting symptoms of bile duct stones are acute pain, jaundice and

sometimes fever due to cholangitis (infection of the duct) with or without sepsis (Ko &

Lee 2002). Bile duct stones may also be a cause of symptoms in patients who have had

their gallbladder removed as described below.


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Post-cholecystectomy syndrome

Post-cholecystectomy syndrome is a term used to describe the presence of

symptoms following cholecystectomy, that can be attributed to the gallbladder or its

removal. These symptoms include pain, nausea, vomiting and jaundice. In some cases,

these patients require further investigation to exclude biliary causes including common

bile duct stones.

Strictures of the bile duct

Strictures of the bile duct may be due to malignancy or benign causes. Further

imaging of the bile duct is indicated if ultrasound and CT scans are equivocal and may

also be used to determine the extent of the stricture for disease staging and planning

management .

Cancer of the pancreas

Ductal adenocarcinoma is the most common type of pancreatic cancer. Common

symptoms include jaundice, abdominal pain and weight loss. Primary cystic tumours are

rarer and more likely to be identified in asymptomatic patients incidentally. Although

rare, the detection and accurate differentiation between benign and malignant cystic

tumours and the extent of disease are critical to plan appropriate treatment.

Cholangiocarcinoma

Cholangiocarcinoma may arise in the bile ducts within the liver (intrahepatic, 10%

of cases) or outside the liver (extrahepatic), including at the hepatic hilus. Incidence of


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this uncommon cancer increases with age and the diagnosis is usually made in patients

over 60 years of age presenting with jaundice and in some cases, abdominal pain,

pruritus and weight loss. Early onset may occur in patients aged between 40 and 60

years with risk factors such as primary sclerosing cholangitis and choledochal cysts.

Cancer of the ampulla of Vater

Ampullary cancer was the primary diagnosis at discharge for 278 patients

hospitalised in Australia in 2002-2003 (Table 3). It presents with biliary obstruction but

also may present with cholangitis or pancreatitis. The early detection of this disease and

distinction from cancer of the pancreas or second part of the duodenum are important

because management is different and early surgery can be curative..

Pancreatitis

Pancreatitis refers to acute, chronic or relapsing inflammation of the gland.

Typical symptoms are abdominal pain, jaundice, malaise and vomiting. Blood tests

show raised pancreatic enzymes. The commonest causes of acute pancreatitis are

gallstone obstruction of the pancreatic duct and alcohol abuse. It also occurs as a

complication of ERCP. Recovery with supportive treatment is usually uneventful;

however, in 10-15% of patients it can be complicated by a systemic inflammatory

response and lead to pancreatic necrosis, which has a high mortality rate.

Chronic pancreatitis is characterised by permanent damage to the gland.

Treatment of chronic pancreatitis involves the management of pain and malabsorption

due to insufficient pancreatic enzymes. In the long term, up to 50% of patients require


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treatment of diabetes. Complications include inflammatory cysts (pseudocysts),

pancreatic stones, pancreatic or biliary duct strictures, duodenal stenosis, portal

hypertension and an increased risk of pancreatic cancer .

Related Studies

Jang, Chong, and Kim (2010) studied the safety of performing ERCP in young

children from Korea. The researchers concluded that ... diagnostic and therapeutic

ERCPs were performed safely and effectively in Korean children for the management of

various biliary and pancreatic diseases. Pediatricians and pediatric surgeons, especially

those working in Asian countries, should become more familiar with ERCP as a

diagnostic and therapeutic modality, as Asia has a high incidence of CCs and

anomalous union of the pancreaticobiliary duct.

According to Chong, Yin and Lim (2005) ERCP is a potentially life-saving

intervention in the elderly population. Our study showed that ERCP is safe in the elderly

Asian populations. In conclusion, our study showed that ERCP is safe in the elderly

Asian population. Minor complications are usually transient and related to sedation, and

mortality is usually related to severity of illness and underlying malignancies. ERCP

should be considered when indicated in the elderly population as this may be life

saving.


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CHAPTER III

METHODOLOGY

Research Design

The study is a qualitative literature review. It utilized relevant research that has

been done on the same field. The results of these studies were extracted to obtain the

relevant data necessary to answer the questions raised in the study.

Selection of the Studies

Studies selected in the study are those that involved comparison of imaging

modalities for detecting biliary obstruction that includes CT and ERCP. The studies

selected includes all or any of the predictors used by the present study in making

comparative evaluation of CT with ERCP. The present study employed a deliberate

sampling of studies was based on the criteria that studies involves an assessment of

different diagnostic imaging modalities for biliary obstructions that include CT and ERCP

and that the assessment includes all or any of the predictors set for comparing and

evaluation of both imaging modalities. Eleven studies qualified on the criteria set for

inclusion in this research.

Data Gathering Procedure

An electronic search was performed using a wide range of data base in order to

obtain the information for the progress of the study. Each study was carefully reviewed

for their content and relevance to present investigation. Twenty-five potential studies


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were screened and initially assessed. Out of these 4 studies were rejected for the title;

the abstract of the remaining 21 were screened and out of these 5 were rejected. The

full content of the 16 studies were read and screened. Two studies were rejected.

Fourteen selected were found potentially relevant and but 3 were rejected for quality.

Finally eleven studies were selected and employed as primary source of data in the

present research.

Data Analysis

The data gathered from the studies selected in the study were assessed

according to the criteria set in the present study. As previously mentioned studies must

include an evaluation of diagnostic modalities for biliary obstruction that includes CT

and ERCP. These studies must include all or any of the data on the rate of sensitivity,

specificity, rate of positive and negative predictive values and rate of detection.


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CHAPTER IV

PRESENTATION, ANALYSIS AND INTERPRETATION OF DATA

This chapter presents the results of the literature review on the diagnostic

accuracy of CT in detecting causes of biliary obstruction in comparison with ERCP.

What is Computed Tomography (CT)

CT is a diagnostic imaging procedure that uses x rays to obtain cross-sectional images

of the body. Since its introduction and rapid adoption into medicine in the mid-1970s,

CT has become recognized as a valuable medical tool for the diagnosis of disease,

trauma, or abnormality and for planning, guiding, and monitoring therapy

(www.wiki.medpedia,com).

1. A motorized table moves the patient through a circular opening in the CT imaging

system.

2. While the patient is inside the opening of the CT imaging system, an x-ray source

and detector within the housing rotate around the patient. A single rotation takes

about 1 second. The x-ray source produces a narrow, fan-shaped beam of x-rays

that passes through a section of the patient's body.

3. A detector opposite from the x-ray source records the x-rays passing through the

patient's body as a "snapshot" image. Many different "snapshots" (at many

angles through the patient) are collected during one complete rotation.
http://wiki.medpedia.com/Imaginghttp://www.wiki.medpedia%2Ccom/http://www.wiki.medpedia%2Ccom/http://wiki.medpedia.com/Imaging


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4. For each rotation of the x-ray source and detector, the image data are sent to a

computer to reconstruct all of the individual "snapshots" into one or multiple

cross-sectional images (slices) of the internal organs and tissues (like the biliary

ducts).

As in any diagnostic procedures, CT is not risk free. Among the main risks

associated with CT ARE:

1. An increased lifetime risk of cancer due to x-ray radiation exposure.

2. Since the procedure in some cases involves use of contrast agent or dye,

there is a possible allergic reactions or kidney failure.

3. The need for additional follow-up tests after receiving abnormal test

results or to monitor the effect of a treatment on disease, such as to

monitor a tumor after surgical removal. Some of these tests may be

invasive and present additional risks.

4. Under some rare circumstances of prolonged, high-dose exposure, x-rays

can cause other adverse health effects, such as skin reddening

(erythema), skin tissue injury, hair loss, cataracts, and potentially, birth

defects (if scanning is done during pregnancy).

Radiation exposure is a concern in both adults and children. However, these

concerns are greater for children because they are more sensitive to radiation and have

a longer life expectancy than adults. As a result, accumulated exposures over a childs

lifetime are more likely to result in an adverse health effect. A childs smaller size also

has an impact on the radiation dose they receive. For example, if a CT scan is

performed on a child using the same parameters as those used on an adult, an


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unnecessarily large dose will be delivered to the child. CT equipment settings (exposure

parameters such as, x-ray tube current, slice thickness, or pitch) can be adjusted to

reduce dose significantly while maintaining diagnostic image .quality(www.hhs.gov.).

What is Endoscopic retrograde cholangio pancreatography (ERCP)

The term endoscopic refers to the endoscope which is a thin, flexible tube with a

tiny video camera and light on the end. The endoscope is used by a highly trained

subspecialist, the gastroenterologist, to diagnose and treat various problems of the GI

tract. The GI tract includes the stomach, intestine, and other parts of the body that are

connected to the intestine, such as the liver, pancreas, and gallbladder.

Retrograde refers to the direction in which the endoscope is used to inject a

liquid enabling X-rays to be taken of the parts of the GI tract called the bile duct system

and pancreas. The process of taking these X-rays is known as

cholangiopancreatography. Cholangio refers to the bile duct system, pancrea to the

pancreas.

ERCP is indicated for the following:

Gallstones which are trapped in the main bile duct

Blockage of the bile duct

Yellow jaundice which turns the skin yellow and the urine dark

Undiagnosed upper-abdominal pain

Cancer of the bile ducts or pancreas

Pancreatitis


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The main symptoms of pancreatitis are acute, severe pain in the upper abdomen,

frequently accompanied by vomiting and fever. The abdomen is tender, and the patient

feels and looks ill. The diagnosis is made by measuring the blood pancreas enzymes

which are elevated. A sound wave test (ultrasound) or abdominal CT exam often shows

an enlarged pancreas. The condition is treated by resting the pancreas while the tissues

heal. This is accomplished through bowel rest, hospitalization, intravenous feeding and,

pain medications.

When pancreatitis is caused by gallstones, it is necessary to remove the

gallbladder. This is usually done after the acute pancreatitis has resolved. At times, an

ERCP (Endoscopic Retrograde CholangioPancreatography) test is recommended. This

involves passing a flexible tube through the mouth and down to the small intestine. A

small catheter is then inserted into the bile duct to see if any stones are present. If so,

they are then removed with the scope (http://www. e-

radiography.net/technique/ercp/ercp.htm).



a. Sensitivity

In a study comparing CT and ERCP in pancreatibiliary disease, Tobin and his co-

authors(2004) found CT to be superior than ERCP in terms of sensitivity having 100%

sensitivity rate compared to 91.7 of the later. But in a study by Pasanen et al (1992) of

diagnositic accuracy in diagnosis of choledochal stones, ERCP performed better with a

sensitivity rate of of 80.6% compared to CTs 23.2%. Tobins et al. study involved only


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57 patients; while that of Pasanen et all consisted of 220 patients. Meanwhile in the

study of Pasanen et al in diagnosis of cholestasis among 220, CT fared better with 97%

compared with ERCP 89%.. Meanwhile in a study comparing with CT among others,

Vipul and Dy, found out that in more than 3000 patients, ERCP performed better in

diagnosing common bile duct stones with 79-93% sensitivity rate compared to CTs 71-

75% rate.

On the other hand a study comparing diagnostic accuracy among different

modalities including CT and ERCP in diagnosing biliary strictures, Rosch, et al (2002),

ERCP has 85% sensitivity rate compared to CTs 77%. The study involved 50 patients.

Pasanen, et al (1991) compared the diagnostic accuracy in obstructive jaundice of CT

and ERCP among others in 187 jaundiced patients. The results indicate that the

sensitivity rate of ERCP is greater at 87% than CTs 77%. In the study of Jong, et al

(2002) ERCP exhibited 90% sensitivity compared to only 40% of CT in biliary

pancreatitis.


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TABLE 1. STUDIES COMPARING CT AND ERCP IN TERMS OF

SENSITIVITY

StudyNo. of Patients

Biliary

Obstruction

Sensitivity

CT(%)

ERCP(%)

Tobin,Vogetzang,Gore andKeigley 57

PancreaticoBiliary 100 91.7

Pasanen, P., et al220 Choledochal

Stones 23.3 80.6

Pasanen, P. et al 220 Cholectasis 97 87

Pasanen, P. et al. 187ObstructiveJaundice 77 87

Rosch,T. Meining,A. et al. 50 BiliaryStrictures 77 85

Rathod, V and Dy, Frederick 3000CommonBile ductStones 71-75 79-93

Moon, Cho et al. 32Biliary

pancreatitis 40 90

b. Specificity

In a study of Rathod and Dy, the specificity value of ERCP is 92-100% which is

greater than the specificity value of CT which is 78-97% in detecting common bile duct

stones. The same trend is noted in the study of Rosch et al (2002). as the specificity of

ERCP is 75% which is greater than the specificity of CT which is 63% in biliary

strictures

Tobin and his associates (2004) declared in their study that in terms of

specificity, ERCP is 100% in diagnosing pancreaticobiliary disease compared to 91% of


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CT. Whereas in a study of 220 patients, Pasanen, et al (1992) claimed that in

diagnosing cholestasis ERCP specificity level is 94% while that of CT is 92%.

TABLE 2. STUDIES COMPARING CT AND ERCP IN TERMS OF

SPECIFICITY

Study No. of Patients BiliaryObstruction

Specificity

CT(%)

ERCP(%)

Tobin,Vogetzang,Gore andKeigley 57Pancreatico

Biliary 100 91.7

Pasanen, P. et al. 187ObstructiveJaundice 92 94

Rosch,T. Meining,A. et al. 50 BiliaryStrictures 63 75

Rathod, V and Dy, Frederick 3000CommonBile ductStones 78-97 92-100


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TABLE 3. STUDIES COMPARING CT AND ERCP

IN TERMS OF DETECTION ACCURACY

StudyNo of

PatientsBiliary

Obstruction(Causes)

CT(%)

ERCP(%)

Zhong,Yao,Li & Xu 82 Gallbladder stone 75.0 80.0

Upadhaya, et al

Zhong,Yao, Li & Xu

100

82

Intrahepatic bileduct stone

85.71

100.0

95.83

100.0

Zhong,Yao,Li & Xu 82 Choledocholithiasis

88.2 94.1

Yang,Ping, et al; 58 Pancreato-biliarytumor

80 92

Zhong,Yao,Li & Xu Gallbladdercarcinoma

75.0 60.0

Wei-Xing et al.,

Zhong,Yao,Li & Xu

41

82Ampullarycarcinoma

84

50.

100

100

Zhong,Yao,Li & Xu 82Pancreatic headcarcinoma 81.8 100

Zhong,Yao,Li & Xu 82Bile papillacarcinoma 66.7 100

Zhong,Yao,Li & Xu 82 Bile duct injury

100. 100

Zhong,Yao,Li & Xu 82 Choledochal cyst

100 100

Zhong,Yao,Li & Xu 82Chronicpancreatitis 75.0 100


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In a study by Zhong, Yao, Li and XU (2003) they evaluate the clinical values of

various imageological methods including CT and ERCP in diagnosing the pancreato-

biliary diseases. The results of their study indicate that the accurate rate in detection of

biliary obstructions such as gallbladder stones for CT 75% and for ERCP is 80%;

intrahepatic bile duct stone is 100% for both methods, but the trend is different from

the study of Upadhaya et al (2006) where ERCP remains superior with accuracy rate of

95.83 as against 85.7% for CT. Zhong, and his associated noted the accuracy of ERCP

and CT in detecting Choledocholithiasis where ERCP remains superior with 94.1% rate

as compared to 88.2% rate for CT.where Zhong et al is 88.2 % for CT and 94.1%; The

same trend is noted by the authors in detecting pancreatic carcinoma(CT-81.8; ERCP-

100%); bile papilla carcinoma (CT-66.7% and ERCP -100%); and chronic pancreatitis

with accuracy rate of 75% for CT and 100% for ERCP. However, the authors show that

both modalities have the same accuracy rate in detecting choledochal cyst and bile duct

stones with 100%. Meanwhile the accuracy rate of detecting pancreato-biliary tumour,

Yang-Ping et al (2007), find ERCP superior with 92% as against 80% rate of CT. In the

study of Wei-Xing, et al found the accuracy rate of ERCP in detecting ampullary

carcinoma to be 100% as against 84% of CT. The same trend is noted in the study of

Zhong, Yao, Li and Xu (2003) where CT accuracy rate is documented as 50% and that

of ERCP as 100%.


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CHAPTER V

SUMMARY, CONCLUSIONS AND RECOMMENDATIONS

This chapter is the culminating part of the study. It presents the summary of

findings, conclusions and recommendations.

Summary of Findings

1.What is Computed Tomography (CT)

CT or computed tomography is a diagnostic imaging procedure that uses x-rays

to obtain cross-sectional images. It is a non-invasive procedure that aid in the correct

diagnosis of biliary obstructions among others. Among the risks in CT procedure to

patients are possible allergy from contrast agent used in some cases and lifetime

exposure to radiation adverse health effects like hair loss, skin injury among others.

2. What is Endoscopic retrograde cholangio pancreatography

(ERCP).

Endoscopic retrograde cholanagiopacreatography is both a diagnostic and

therapeutic tool. Endoscopic refers to a thin, flexible tube with a tiny video camera and

light at the end, while retrograde refers to the direction in which the endoscope is used

to inject a liquid enabling X-rays to be taken of the parts of the GI tract called the bile

duct system and pancreas. ERCP is an invasive diagnostic modality indicated in

detecting biliary obstructions.


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a. Sensitivity

Two studies that of Tobin, and Pasanen had indicated that CT has higher level of

sensitivity rate in detecting pancreatico biliary; and cholectasis; compared with ERCP;

however the rests of the 7 studies reviewed indicated that the accuracy rate of ERCP is

consistently higher than CT in detecting obstructive jaundice, biliary strictures; common

bile duct stones, Choledochal stones and biliary pancreatitis.

b. Specificity

According to three studies reviewed the level of specificity of CT is lower in

diagnosing obstructive jaundice; detecting biliary strictures and common bile duct

stones compared with the rate of ERCP; but is found higher than the later in detecting

pancreaticobiliary.


In all biliary obstructions examined by four studies indicate that only choledochal

cysts, bile duct injury had CT in equal footing with ERCP. But detecting gallbladder

stones, intrahepatic bile duct stones except with 1 study; choledocholithaiasis,

pancreatobiliary tumor, gallbladder carcinoma; pancreatic head carcinoma, bile papilla

carcinoma and chronic pancreatic, CT remains inferior to ERCP.


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Conclusions

1. Computed tomography is a non-invasive diagnostic imaging procedure that

aided diagnosis and detection of some biliary obstructions.

2. Endoscopic retrograde cholangiography is an invasive diagnostic imaging tool

and therapeutic instrument for diagnosing and detecting biliary obstruction.

3. In comparison between CT and ERCP, CT has lower sensitivity rate compared

to ERCP in detecting biliary obstructions like choledochal stones, obstructive jaundice,

biliary strictures; common bile duct stones and biliary pancreatitis.

5. In terms of specificity ERCP is found superior among diagnostic imaging

modalities including CT. Only 1 studies had found out that CT has 100% specificity in

detecting pancreatico biliary as against 91.7% of ERCP . The rest the studies showed

that ERCP remains superior with CT in terms of specificity rate in detecting obstructive

jaundice, biliary strictures and common bile duct stones.

6. As to detection accuracy, ERCP had been proven by studies reviewed to

remain the gold standard for diagnosis of biliary obstruction.

Recommendations

The researcher has noted in the course of researching for studies, there has

been no local studies on the subject. It is believed that cases obstructive biliary disease

is increasing in the country. And the need for accurate diagnosis for biliary obstructions

demands the need for adequate knowledge among our doctors of clinical values of

different diagnostic imaging tools. For this reason, the researcher recommends studies

on the subject beyond systematic literature reviews.


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Figure 1. Pathway flow

of diagnosing causes of

cholestatic jaundice

source:www.ima in athwa s.health.wa. ov.


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APPENDIX B

SUMMARY OF SELECTION PROCESS

Potentially relevant

studies identified

and screened

n = 25

Total abstract

screenedn=21

Total full paper

screened

n=16

Studies potentially

relevant

n=14

Included Studiesn=11

Studies rejected for

title

n=4

Studies Rejected for

abstract

n=5

Rejected full papers

n=2

Studies excluded

for quality

n=3

diagnostic accuracy ct and ercp

Documents