Can computed tomography with coronal reconstruction improve the diagnosis of choledocholithiasis?

Incremental diagnostic value of virtual non-contrast dual-energy CT for the diagnosis of choledocholithiasis over conventional unenhanced CT

PURPOSE

The purpose of this study was to evaluate the incremental diagnostic value of virtual non-contrast (VNC) images derived from unenhanced dual-energy computed tomography (CT) for the diagnosis of choledocholithiasis by comparison with conventional unenhanced CT.

MATERIALS AND METHODS

Eighty-nine patients with gallbladder stones who had undergone both abdominal unenhanced dual-energy CT and magnetic resonance cholangiopancreatography (MRCP) were retrospectively included. There were 53 men and 36 women, with a mean age of 54 ± 13 (standard deviation) years (age range: 41-67 years). VNC and conventional CT images were generated. Two independent radiologists evaluated the presence of choledocholithiasis in three reading sessions (session 1, conventional unenhanced CT images; session 2, VNC images; session 3, conventional unenhanced CT plus VNC images). The reading time to identify choledocholithiasis was recorded. Inter-reader agreement was measured by using the Cohen kappa (κ) test. Incremental diagnostic value of VNC imaging when combined with conventional unenhanced CT was assessed based on discrimination (area under the curve [AUC]) and clinical utility (decision curve analysis). The diagnostic performance of dual-energy CT and that of MRCP were compared using DeLong test.

RESULTS

Using the standard of reference, 39 patients (39/89; 44%) had choledocholithiasis. The diagnosis of choledocholithiasis was improved using VNC images in combination with conventional unenhanced CT (AUC, 0.877; 95% confidence interval [CI]: 0.808, 0.947) by comparison with conventional unenhanced CT alone (AUC, 0.789; 95% CI: 0.718, 0.877) (P = 0.033) and achieved almost perfect inter-reader agreement (κ = 0.88; 95% CI: 0.72, 1.00) for the diagnosis of choledocholithiasis, without lengthening the median reading time (16.2 s for the combination of conventional CT and VNC images vs. 14.7 s for conventional CT alone; P= 0.325). Based on decision curve analysis, adding VNC imaging to conventional unenhanced CT resulted in a higher net benefit among most of decision thresholds. No differences in diagnostic performance were found between the combination of conventional unenhanced CT and VNC imaging (AUC, 0.877; 95% CI: 0.808, 0.947) and MRCP (AUC, 0.913; 95% CI: 0.852, 0.974) (P= 0.458).

CONCLUSIONS

VNC images derived from dual-energy unenhanced CT have incremental diagnostic value for the diagnosis of choledocholithiasis. Unenhanced CT in a dual-energy mode may be a useful tool for the diagnosis of choledocholithiasis.

Evidence-based clinical practice guidelines for cholelithiasis 2021

The Japanese Society of Gastroenterology first published evidence-based clinical practice guidelines for cholelithiasis in 2010, followed by a revision in 2016. Currently, the revised third edition was published to reflect recent evidence on the diagnosis, treatment, and prognosis of cholelithiasis conforming to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Following this revision, the present English version of the guidelines was updated and published herein. The clinical questions (CQ) in the previous version were reviewed and rearranged into three newly divided categories: background questions (BQ) dealing with basic background knowledge, CQ, and future research questions (FRQ), which refer to issues that require further accumulation of evidence. Finally, 52 questions (29 BQs, 19 CQs, and 4 FRQs) were adopted to cover the epidemiology, pathogenesis, diagnosis, treatment, complications, and prognosis. Based on a literature search using MEDLINE, Cochrane Library, and Igaku Chuo Zasshi databases for the period between 1983 and August 2019, along with a manual search of new information reported over the past 5 years, the level of evidence was evaluated for each CQ. The strengths of recommendations were determined using the Delphi method by the committee members considering the body of evidence, including benefits and harms, patient preference, and cost-benefit balance. A comprehensive flowchart was prepared for the diagnosis and treatment of gallbladder stones, common bile duct stones, and intrahepatic stones, respectively. The current revised guidelines are expected to be of great assistance to gastroenterologists and general physicians in making decisions on contemporary clinical management for cholelithiasis patients.

Multiple Field-of-View Based Attention Driven Network for Weakly Supervised Common Bile Duct Stone Detection

OBJECTIVE

Common bile duct (CBD) stones caused diseases are life-threatening. Because CBD stones locate in the distal part of the CBD and have relatively small sizes, detecting CBD stones from CT scans is a challenging issue in the medical domain.

METHODS AND PROCEDURES

We propose a deep learning based weakly-supervised method called multiple field-of-view based attention driven network (MFADNet) to detect CBD stones from CT scans based on image-level labels. Three dominant modules including a multiple field-of-view encoder, an attention driven decoder and a classification network are collaborated in the network. The encoder learns the feature of multi-scale contextual information while the decoder with the classification network is applied to locate the CBD stones based on spatial-channel attentions. To drive the learning of the whole network in a weakly-supervised and end-to-end trainable manner, four losses including the foreground loss, background loss, consistency loss and classification loss are proposed.

RESULTS

Compared with state-of-the-art weakly-supervised methods in the experiments, the proposed method can accurately classify and locate CBD stones based on the quantitative and qualitative results.

CONCLUSION

We propose a novel multiple field-of-view based attention driven network for a new medical application of CBD stone detection from CT scans while only image-levels are required to reduce the burdens of labeling and help physicians automatically diagnose CBD stones. The source code is available at https://github.com/nchucvml/MFADNet after acceptance.

CLINICAL IMPACT

Our deep learning method can help physicians localize relatively small CBD stones for effectively diagnosing CBD stone caused diseases.

Bile duct penetrating duodenal wall sign: a novel computed tomography finding of common bile duct stone impaction into duodenal major papilla

PURPOSE

Impacted common bile duct stones cause severe acute cholangitis. However, the early and accurate diagnosis, especially iso-attenuating stone impaction, is still challenging. Therefore, we proposed and validated the bile duct penetrating duodenal wall sign (BPDS), which shows the common bile duct penetrating the duodenal wall on coronal reformatted computed tomography (CT), as a novel sign of stone impaction.

METHODS

Patients who underwent urgent endoscopic retrograde cholangiopancreatography (ERCP) for acute cholangitis due to common bile duct stones were retrospectively enrolled. Stone impaction was defined by endoscopic findings as a reference standard. Two abdominal radiologists blinded to clinical information interpreted CT images to record the presence of the BPDS. The diagnostic accuracy of the BPDS to diagnose stone impaction was analyzed. Clinical data related to the severity of acute cholangitis were compared between patients with and without the BPDS.

RESULTS

A total of 40 patients (mean age 70.6 years; 18 female) were enrolled. The BPDS was observed in 15 patients. Stone impaction occurred in 13/40 (32.5%) cases. Overall accuracy, sensitivity, and specificity were 34/40 (85.0%), 11/13 (84.6%), and 23/27 (85.2%), respectively; 14/16 (87.5%), 5/6 (83.3%), and 9/10 (90.0%) for iso-attenuating stones; and 20/24 (83.3%), 6/7 (85.7%), and 14/17 (82.4%) for high-attenuating stones. Interobserver agreement of the BPDS was substantial (κ = 0.68). In addition, the BPDS was significantly correlated with the number of factors in the systemic inflammatory response syndrome (P = 0.03) and total bilirubin (P = 0.04).

CONCLUSION

The BPDS was a unique CT imaging finding to identify common bile duct stone impaction regardless of stone attenuation with high accuracy.

[Effectiveness of Radiological Technologists in Reporting Computed Tomography Findings in After-hour Emergencies]

PURPOSE

This study investigated the effectiveness of assistive work of radiological technologists (RTs) in conducting computed tomography (CT)/magnetic resonance imaging (MRI) during emergencies.

METHODS

In total, 2681 examinations in 2294 patients who underwent CT or MRI during our after-hours clinic hours were conducted. The emergency of the diseases was classified into three categories: emergency diseases, semi-emergency diseases, and non-emergency diseases. The reading report of the RTs group, resident physicians (RPs) group, and senior physicians (SPs) group were used to calculate the sensitivity, specificity, and accuracy.

RESULTS

The RTs group had an accuracy of 87.0% for emergency and semi-emergency diseases. The sensitivity of the combined RTs/RPs/SPs group was higher than that of the RPs and SPs group alone.

CONCLUSION

After-hours help from RTs for emergency and semi-emergency diseases enhanced sensitivity and thus demonstrated the effectiveness in emergency care.

Destiny for Rendezvous: Is Cholecysto/Choledocholithiasis Better Treated with Dual- or Single-Step Procedures?

Biliary lithiasis is common worldwide, affecting almost 20% of the general population, though few experience symptoms. The frequency of choledocholithiasis in patients with symptomatic cholelithiasis is estimated to be 10-33%, depending on patients' age. Unlike gallbladder lithiasis, the medical and surgical treatment of common bile duct stones is uncertain, having changed over the last few years. The prior gold standard treatment for cholelithiasis and choledocholithiasis was open cholecystectomy with bile duct clearance, choledochotomy, and/or surgical sphincterotomy. In the last 10-15 years, new treatment approaches to the complex pathology of choledocholithiasis have emerged with the advent of endoscopic retrograde cholangiopancreatography (ERCP), laparoscopic surgery, and advanced diagnostic procedures. Although ERCP followed by laparoscopic cholecystectomy is the preferred mode of management, a single-step strategy (laparo-endoscopic rendezvous) has gained acceptance due to lesser morbidity and a lower risk of iatrogenic damage. Given the above, a tailored approach relying on careful evaluation of the disease is necessary in order to minimize complication risks and overall costs. Yet, the debate remains open, with no consensus on the superiority of laparo-endoscopic rendezvous to more conventional approaches.

Endoscopic ultrasound avoids adverse events in high probability choledocholithiasis patients with a negative computed tomography

BACKGROUND

The current guideline recommends patients who meet high probability criteria for choledocholithiasis to receive endoscopic retrograde cholangiopancreatography (ERCP). However, adverse events can occur during ERCP. Our goal is to determine whether endoscopic ultrasound (EUS) before ERCP can avoid unnecessary ERCP complications, especially in patients with a negative CT scan.

METHODS

A total of 604 patients with high probability of choledocholithiasis were screened and 104 patients were prospectively enrolled. Patients with malignant biliary obstruction, altered GI anatomy, and choledocholithiasis on CT scan were excluded. Among them, 44 patients received EUS first, and ERCP if choledocholithiasis present (EUS-first group). The other 60 patients received ERCP directly (ERCP-first group). The baseline characteristics, presence of choledocholithiasis, and complications were compared between groups. All patients were followed for 3 months to determine the difference in recurrent biliary event rate. Cost-effectiveness was compared between the two strategies.

RESULTS

There was no marked difference in age, sex, laboratory data, presenting with pancreatitis, and risk factors for choledocholithiasis. Overall, 51 patients (49.0%) had choledocholithiasis, which did not justify the risk of direct ERCP. In the EUS-first group, 27 (61.4%) ERCP procedures were prevented. The overall complication rate was significantly lower in the EUS-first group compared to the ERCP-fist group (6.8% vs. 21.7%, P = 0.04). The number-needed-to-treat to avoid one unnecessary adverse event was 6.71. After a 3-month follow-up, the cumulative recurrence biliary event rates were similar (13.6% vs. 15.0%, P = 0.803). EUS-first strategy was more cost-effective than the ERCP-first strategy (mean cost 2322.89$ vs. 3175.63$, P = 0.002).

CONCLUSIONS

In high-probability choledocholithiasis patients with a negative CT, the EUS-first strategy is cost-effective, which can prevent unnecessary ERCP procedures and their complications.

Controversies in ERCP: Indications and preparation

The aim of the series of papers on controversies of biliopancreatic drainage procedures is to discuss the pros and cons of the varying clinical practices and techniques in ERCP and EUS for drainage of biliary and pancreatic ducts. The first part focuses on indications, clinical and imaging prerequisites before ERCP, sedation options, post-ERCP pancreatitis (PEP) prophylaxis, and other related technical topics. In the second part, specific procedural ERCP-techniques including precut techniques and its timing as well as management algorithms are discussed. In addition, controversies in EUS-guided bile duct and pancreatic drainage procedures are under preparation.

Remaining issues of recommended management in current guidelines for asymptomatic common bile duct stones

Current guidelines for treating asymptomatic common bile duct stones (CBDS) recommend stone removal, with endoscopic retrograde cholangiopancreatography (ERCP) being the first treatment choice. When deciding on ERCP treatment for asymptomatic CBDS, the risk of ERCP-related complications and outcome of natural history of asymptomatic CBDS should be compared. The incidence rate of ERCP-related complications, particularly of post-ERCP pancreatitis for asymptomatic CBDS, was reportedly higher than that of symptomatic CBDS, increasing the risk of ERCP-related complications for asymptomatic CBDS compared with that previously reported for biliopancreatic diseases. Although studies have reported short- to middle-term outcomes of natural history of asymptomatic CBDS, its long-term natural history is not well known. Till date, there are no prospective studies that determined whether ERCP has a better outcome than no treatment in patients with asymptomatic CBDS or not. No randomized controlled trial has evaluated the risk of early and late ERCP-related complications vs the risk of biliary complications in the wait-and-see approach, suggesting that a change is needed in our perspective on endoscopic treatment for asymptomatic CBDS. Further studies examining long-term complication risks of ERCP and wait-and-see groups for asymptomatic CBDS are warranted to discuss whether routine endoscopic treatment for asymptomatic CBDS is justified or not.

Dual-layer spectral detector computed tomography versus magnetic resonance cholangiopancreatography for biliary stones

OBJECTIVE

Dual-layer spectral detector computed tomography (DLCT) can detect noncalcified biliary stones. The diagnostic ability of DLCT for detecting biliary stones may be comparable to that of magnetic resonance cholangiopancreatography (MRCP). This study seeks to compare the diagnostic ability for biliary stones between these two imaging modalities.

METHODS

This retrospective study included 102 cases with a diagnosis of biliary stones including gallstones (n = 66) and common bile duct (CBD) stones (n = 25) or spontaneously passing CBD stones (n = 11). The reference standard used was operative findings, endoscopic retrograde cholangiopancreatography or follow-up over 6 months. In DLCT, 120-kVp images, 40-keV virtual monoenergetic images and material decomposition images were created. We compared the diagnostic ability of DLCT and MRCP for biliary stones using the McNemar's test.

RESULTS

The sensitivity and specificity of DLCT versus MRCP for biliary stones were 91.2% versus 95.6% and 90.9% versus 90.9%. Thus, the sensitivity and specificity were not significantly different (P = 0.25 and P = 1.0). Although in small stones (<9 mm) the sensitivity of calcified stones was not different between DLCT and MRCP (100% versus 92.5%), the sensitivity of noncalcified stones in DLCT was lower than that in MRCP (38.5% versus 100%).

CONCLUSION

The diagnostic ability of biliary stones in DLCT appears comparable to that of MRCP in overall cases. However, detecting noncalcified stones less than 9 mm in size is limited in DLCT.

ACR Appropriateness Criteria® Jaundice

Jaundice is the end result of myriad causes, which makes the role of imaging in this setting particularly challenging. In the United States, the most common causes of all types of jaundice fall into four categories including hepatitis, alcoholic liver disease, blockage of the common bile duct by a gallstone or tumor, and toxic reaction to a drug or medicinal herb. Clinically, differentiating between the various potential etiologies of jaundice requires a detailed history, targeted physical examination, and pertinent laboratory studies, the results of which allow the physician to categorize the type of jaundice into mechanical or nonmechanical causes. Imaging modalities used to evaluate the jaundiced patient (all etiologies) include abdominal ultrasound (US), CT, MR cholangiopancreatography, endoscopic retrograde cholangiopancreatography and endoscopic US. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Combining endoscopic ultrasound and tumor markers improves the diagnostic yield on the etiology of common bile duct dilation secondary to periampullary pathologies

Background

Unexplained common bile duct (CBD) dilatation may be caused by many etiologies, such as periampullary tumors, a pancreatic neoplasm, choledocholithiasis or an inflammatory stenosis. The aim of this study is to evaluate the diagnostic yield of endoscopic ultrasonography (EUS) in patients with unexplained CBD dilatation, in combination with tumor markers, liver chemistry, symptoms, surgical history and whether there is dilatation of the pancreatic duct (PD).

Methods

From January 2016 to July 2017, 115 patients were referred for EUS in our center for CBD dilatation of an unknown etiology. A treatment plan is made based on the EUS result combined with the other clinical information. The final diagnosis is determined by surgical histology or follow-up of at least 3 months.

Results

The sensitivity, specificity and accuracy of EUS for patients with choledocholithiasis were 100.0% (10/10), 100.0% (105/105) and 100.0% (115/115), respectively. The sensitivity, specificity and accuracy of EUS for patients with periampullary tumor were 86.5% (32/37), 89.7% (70/78) and 88.7% (102/115), respectively. The sensitivity, specificity and accuracy of EUS for patients with inflammatory stenosis were 88.2% (60/68), 89.4% (42/47) and 88.7% (102/115), respectively. The overall accuracy of EUS for diagnosing an undetermined etiology for CBD dilatation was 88.7% (102/115) and was higher than the accuracy of ultrasound (US) (64.1%), computed tomography (CT) (66.2%), magnetic resonance imaging (MRI) (67.0%) or PET-CT (66.0%). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of EUS combined with tumor markers for patients with malignant dilatation of CBD were 91.9% (34/37), 97.4% (76/78), 94.4% (34/36), 96.2% (76/79) and 95.7% (110/115), respectively. PD dilation (P=0.026) and weight loss (P=0.035) had significant predictive values of malignancy.

Conclusions

EUS is an effective diagnostic tool for determining the etiology of a CBD dilatation, and offers meaningful information for guiding a treatment plan. EUS used in conjunction with tumor markers has high yield in differentiating benign and malignant CBD dilatation. More attention should be paid to patients with PD dilation or weight loss to prevent misdiagnosis of malignant CBD dilation.

Updated guideline on the management of common bile duct stones (CBDS)

Common bile duct stones (CBDS) are estimated to be present in 10-20% of individuals with symptomatic gallstones. They can result in a number of health problems, including pain, jaundice, infection and acute pancreatitis. A variety of imaging modalities can be employed to identify the condition, while management of confirmed cases of CBDS may involve endoscopic retrograde cholangiopancreatography, surgery and radiological methods of stone extraction. Clinicians are therefore confronted with a number of potentially valid options to diagnose and treat individuals with suspected CBDS. The British Society of Gastroenterology first published a guideline on the management of CBDS in 2008. Since then a number of developments in management have occurred along with further systematic reviews of the available evidence. The following recommendations reflect these changes and provide updated guidance to healthcare professionals who are involved in the care of adult patients with suspected or proven CBDS. It is not a protocol and the recommendations contained within should not replace individual clinical judgement.

Efficacy of Endoscopic Ultrasonography in Evaluation of Undetermined Etiology of Common Bile Duct Dilatation on Abdominal Ultrasonography

BACKGROUND The cause of common bile duct (CBD) dilatation cannot be determined by imaging modalities in many patients. The aim of this study was to assess the value of endoscopic ultrasonography (EUS) in detecting the cause of CBD dilatation in patients in whom ultrasonography could not demonstrate the cause of dilation. METHODS Prospectively, 152 consecutive patients who were referred for evaluation of dilated CBD (diameter ≥7 mm) of undetermined origin by ultrasonography were included in this study. All the patients underwent EUS. Final diagnoses were determined by using endoscopic retrograde cholangiopancreatography (ERCP), EUS-guided fine needle aspiration (FNA), surgical exploration, or follow-up for at least 10 months. Patients with choledocholithiasis were referred for ERCP and sphincterotomy, and patients with operable tumors were referred for surgery.Patients with inoperable tumors underwent biliary stenting with or without tchemoradiotherapy. RESULTS 152 patients (54% female) with dilated CBD were included. Mean (±SD) age of the patients was 60.4 (±17.3) years. The mean CBD diameter for all study group in transabdominal ultrasonography and EUS were 11.7 millimeter and 10.1 millimeter, respectively. Most of the patients with dilated CBD and abnormal liver function test (LFT) had an important finding in EUS and follow-up diagnosis including peri-ampullary tumors. Mean diameter of CBD in patients with and without abnormal LFT were 10.5 IU/L and 12.1 IU/L, respectively. Final diagnoses included choledocholithiasis in 32 (21.1%),passed CBD stone in 35 (23%), opium-induced CBD dilation in 14 (9.2%), post-cholecystectomy states in 20 (13.1%), ampullary adenoma/carcinoma in 15 (15.8%), cholangiocarcinoma in 14 (9.2%), and pancreatic head cancer in9 (5.9%) patients. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of EUS for patients with abnormal EUS were 89.5%, 100.0%, 100.0%, 91.2%, and 90.9%, respectively. CONCLUSION After diagnosis of CBD dilation by transabdominal ultrasonography, EUS may be a reasonable choice for determining the etiology of dilated CBD and tumor staging.

Staged multidisciplinary step-up management for necrotizing pancreatitis

Background

Some 15 per cent of all patients with acute pancreatitis develop necrotizing pancreatitis, with potentially significant consequences for both patients and healthcare services.

Methods

This review summarizes the latest insights into the surgical and medical management of necrotizing pancreatitis. General management strategies for the treatment of complications are discussed in relation to the stage of the disease.

Results

Frequent clinical evaluation of the patient's condition remains paramount in the first 24–72 h of the disease. Liberal goal-directed fluid resuscitation and early enteral nutrition should be provided. Urgent endoscopic retrograde cholangiopancreatography is indicated when cholangitis is suspected, but it is unclear whether this is appropriate in patients with predicted severe biliary pancreatitis without cholangitis. Antibiotic prophylaxis does not prevent infection of necrosis and antibiotics are not indicated as part of initial management. Bacteriologically confirmed infections should receive targeted antibiotics. With the more conservative approach to necrotizing pancreatitis currently advocated, fine-needle aspiration culture of pancreatic or extrapancreatic necrosis will less often lead to a change in management and is therefore indicated less frequently. Optimal treatment of infected necrotizing pancreatitis consists of a staged multidisciplinary ‘step-up’ approach. The initial step is drainage, either percutaneous or transluminal, followed by surgical or endoscopic transluminal debridement only if needed. Debridement is delayed until the acute necrotic collection has become ‘walled-off’.

Conclusion

Outcome following necrotizing pancreatitis has improved substantially in recent years as a result of a shift from early surgical debridement to a staged, minimally invasive, multidisciplinary, step-up approach.

Infections of the biliary tract

Infection of the biliary tract, or cholangitis, is a potentially life-threatening condition. Bile duct stones are the most common cause of biliary obstruction predisposing to cholangitis. The key components in the pathogenesis of cholangitis are biliary obstruction and biliary infection. Several underlying mechanisms of bactibilia have been proposed. Characteristic clinical features of cholangitis include abdominal pain, fever, and jaundice. A combination of clinical features with laboratory tests and imaging studies are frequently used to diagnose cholangitis. Endoscopic retrograde cholangiopancreatography is the best diagnostic test. Less invasive imaging tests may be performed initially in clinically stable patients with uncertain diagnoses.

Common bile duct stones on multidetector computed tomography: Attenuation patterns and detectability

AIM: To investigate the attenuation patterns and detectability of common bile duct (CBD) stones by multidetector computed tomography (MDCT).

METHODS: Between March 2010 and February 2012, 191 patients with suspicion of CBD stones undergoing both MDCT and endoscopic retrograde cholangiopancreatography (ERCP) were enrolled and reviewed retrospectively. The attenuation patterns of CBD stones on MDCT were classified as heavily calcified, radiopaque, less radiopaque, or undetectable. The association between the attenuation patterns of CBD stones on MDCT and stone type consisting of pure cholesterol, mixed cholesterol, brown pigment, and black pigment and the factors related to the detectability of CBD stones by MDCT were evaluated.

RESULTS: MDCT showed CBD stones in 111 of 130 patients in whom the CBD stones were demonstrated by ERCP with 85.4% sensitivity. The attenuation patterns of CBD stones on MDCT were heavily calcified 34 (26%), radiopaque 31 (24%), less radiopaque 46 (35%), and undetectable 19 (15%). The radiopacity of CBD stones differed significantly according to stone type (P < 0.001). From the receiver operating characteristic curve, stone size was useful for the determination of CBD stone by MDCT (area under curve 0.779, P < 0.001) and appropriate cut-off stone size on MDCT was 5 mm. The factors related to detectability of CBD stones on MDCT were age, stone type, and stone size on multivariate analysis (P < 0.05).

CONCLUSION: The radiopacity of CBD stones on MDCT differed according to stone type. Stone type and stone size were related to the detectability by MDCT, and appropriate cut-off stone size was 5 mm.

Linear echoendoscope-guided ERCP for the diagnosis of occult common bile duct stones

Background

Less than 67% of patients with intermediate risk for common bile duct (CBD) stones require therapeutic intervention. It is important to have an accurate, safe, and reliable method for the definitive diagnosis of CBD stones before initiating therapeutic endoscopic retrograde cholangiopancreatography (ERCP). Few publications detail the diagnostic efficacy of linear echoendoscopy (EUS) for CBD stones.

Methods

30 patients with biliary colic, pancreatitis, unexplained derangement of liver function tests, and/or dilated CBD without an identifiable cause were enrolled in the study. When a CBD stone was disclosed by linear EUS, ERCP with stone extraction was performed. Patients who failed ERCP were referred for surgical intervention. If no stone was found by EUS, ERCP would not be performed and patients were followed-up for possible biliary symptoms for up to three months.

Results

The major reason for enrollment was acute pancreatitis. The mean predicted risk for CBD stones was 47% (28–61). Of the 12 patients who were positive for CBD stones by EUS, nine had successful ERCP, one failed ERCP (later treated successfully by surgical intervention) and two were false-positive cases. No procedure-related adverse events were noted. For those 18 patients without evidence of CBD stones by EUS, no false-negative case was noted during the three-month follow-up period. Linear EUS had sensitivity, specificity, positive and negative predicted values for the detection of CBD stones of 1, 0.9, 0.8 and 1, respectively.

Conclusion

Linear EUS is safe and efficacious for the diagnosis of occult CBD stones in patients with intermediate risk for the disease.

Advances in the investigation of obstructive jaundice

The causes of obstructive jaundice are varied, and timely, accurate methods of investigation are essential to avoid the development of complications. Imaging, invasive or non-invasive, should be carefully selected depending on the suspected underlying pathology in order to determine the degree and level of obstruction along with tissue acquisition and staging where relevant. Several imaging techniques will also allow subsequent therapeutic interventions to be carried out. This article reviews advances in the investigation of obstructive jaundice, highlighting recent developments, many of which at present remain restricted to large centres of expertise, but are likely to become more widespread in use as research progresses and local experience continues to improve.

Biliary, pancreatic, and hepatic imaging for the general surgeon

Technologic advancements have allowed imaging modalities to become more useful in the diagnosis of hepatobiliary and pancreatic disorders. Computed tomography scanners now use multidetector row technology with contrast-delayed imaging for quicker and more accurate imaging. Magnetic resonance imaging with cholangiopancreatography can more clearly delineate liver lesions and the biliary and pancreatic ducts, and can diagnose pathologic conditions early in their course. Newer technologies, such as single-operator cholangioscopy and endoscopic ultrasonography, have sometimes shown superiority to traditional modalities. This article addresses the literature regarding available imaging techniques in the diagnosis and treatment of common surgical hepatobiliary and pancreatic diseases.