Detection of biliary duct narrowing and choledocholithiasis: accuracy of portal venous phase multidetector CT

Part 2: Current Concepts in Radiologic Imaging & Intervention in Acute Biliary Tract Diseases

Acute cholangitis is encountered commonly in critically ill, often elderly, patients. The most common causes of cholangitis include choledocholithiasis, biliary strictures, and infection from previous endoscopic, percutaneous, or surgical intervention of the biliary tract. Rare causes of acute cholangitis in the United States include sclerosing cholangitis and recurrent pyogenic cholangitis, the latter predominantly occurring in immigrants of Asian descent. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, gastroenterologists, endoscopists, and infectious disease physicians typically involved in the care of these patients. In this paper intended for intensivists predominantly, we will review the imaging findings and radiologic interventional management of critically ill patients with acute cholangitis, primary and secondary sclerosing cholangitis, and recurrent pyogenic cholangitis.

Unnecessary endoscopic retrograde cholangiopancreatography associated with the spontaneous passage of common bile duct stones into the duodenum: a multicenter retrospective study

BACKGROUND

Unnecessary endoscopic retrograde cholangiopancreatography (ERCP) after spontaneous passage of common bile duct stones (CBDSs) should be avoided. This study aimed to examine the cumulative diagnosis rate and the predictive factors of spontaneous CBDS passage during the interval between the imaging diagnosis and ERCP.

METHODS

This multicenter retrospective study included 1260 consecutive patients with native papilla diagnosed with CBDSs using imaging modalities. Predictive factors and cumulative diagnosis rate of spontaneously passed CBDSs during the interval between imaging diagnosis and ERCP were analyzed.

RESULTS

The overall cumulative diagnosis rate of spontaneous CBDS passage was 6.2% (78/1260) during a mean interval of 5.0 days. In the multivariate analysis, CBDS sized < 6 mm on diagnostic imaging, solitary CBDS on diagnostic imaging, intervals between the imaging diagnosis and ERCP, and nondilated common bile duct (< 10 mm) were the significant factors associated with spontaneous CBDS passage. Specifically, the cumulative diagnosis rate of spontaneous passage was significantly higher in patients with solitary and CBDSs sized < 6 mm than in those with other CBDSs (14.4% [54/376] vs. 2.7% [24/884], P < 0.001). In both the asymptomatic and symptomatic groups, the cumulative diagnosis rate of the spontaneous passage of CBDSs was significantly higher in patients with solitary and CBDSs sized < 6 mm on diagnostic imaging than in those with multiple and/or CBDSs sized ≥ 6 mm on diagnostic imaging during a mean interval of 20.5 and 2.4 days, respectively (asymptomatic group: 22.4% [15/67] vs. 3.5% [4/113], P < 0.001, symptomatic group: 12.6% [39/309] vs. 2.6% [20/771], P < 0.001).

CONCLUSIONS

Solitary and CBDSs sized < 6 mm on diagnostic imaging can often lead unnecessary ERCP due to spontaneous passage. Preliminary endoscopic ultrasonography immediately before ERCP is recommended, especially in patients with solitary and small CBDSs on diagnostic imaging.

Endoscopic ultrasound versus magnetic resonance cholangiopancreatography for the diagnosis of computed tomography-negative common bile duct stone: Prospective randomized controlled trial

OBJECTIVES

For suspected common bile duct stone (CBDS) missed on computed tomography (CT), there is no clear evidence on whether endoscopic ultrasound (EUS) or magnetic resonance cholangiopancreatography (MRCP) is the better diagnostic tool. We aimed to compare the diagnostic accuracy of EUS and MRCP for cases of missed CBDS on CT.

METHODS

Patients suspected of having CBDS were enrolled and randomly allocated to the EUS or MRCP group. Upon the initial examination, those having CBDS or sludge formation underwent endoscopic retrograde cholangiopancreatography (ERCP), while those who were CBDS-negative underwent a second examination with either MRCP or EUS, which was distinct from the initial diagnostic procedure. The primary outcome was diagnostic accuracy, and the secondary outcomes were diagnostic ability, detection rate and characteristics of CBDS in the second examination, and the frequency of adverse events.

RESULTS

Between April 2019 and January 2021, 50 patients were enrolled in the study. The accuracy was 92.3% for EUS and 68.4% for MRCP (P = 0.055). EUS showed 100% sensitivity, 88.2% specificity, 81.8% positive predictive value, and 100% negative predictive value, and MRCP showed 33.3% sensitivity, 84.6% specificity, 50% positive predictive value, and 73.3% negative predictive value. The CBDS detection rate in the second examination was 0% for MRCP after a negative EUS and 35.7% for EUS after a negative MRCP (P = 0.041). No adverse events occurred in any of the patients.

CONCLUSIONS

Endoscopic ultrasound may be a superior diagnostic tool compared to MRCP for the detection of CBDS that are undetected on CT. (UMIN000036357).

The high rate of spontaneous migration of small size common bile duct stones may allow a significant reduction in unnecessary ERCP and related complications: results of a retrospective, multicenter study

INTRODUCTION

Common bile duct stones (CBDS) can spontaneously migrate through the duodenal papilla. In this case, ERCP could be unnecessary and a significant rate of complications could be avoided. In this study, we aim at retrospectively evaluating the rate of spontaneous stone passage in patients with an imaging diagnosis of CBDS and at analysing the factors associated to spontaneous stone migration.

METHODS

We conducted a retrospective multi-centre analysis of patients undergoing ERCP for CBDS in a 12-month period. 1016 patients with CBDS were analysed. In all patients CBDS was diagnosed with adequate imaging methods performed prior to ERCP. ERCPs with failed biliary cannulation were excluded. Data regarding patients' characteristics, imaging findings and ERCP procedure were analysed.

RESULTS

1016 patients with CBDS undergoing ERCP were analysed (male sex 43.3%; mean age 69.9 ± 16.5 years). Diagnosis of CBDS was obtained by EUS in 415 patients (40.8%), MR in 343 (33.8%), CT in 220 (21.7%), and US in 38 (3.7%). No stones were found at ERCP in 179 patients (17.6%), in 14 (6.2%) when ERCP was performed within 6 h from imaging study, in 114 (18.5%) between 7 h and 7 days, in 32 (24.6%) between 8 and 29 days, and in 19 (43.2%) after 30 days. The rate of unnecessary ERCP occurred significantly more frequently in patients in whom imaging methods demonstrated either sludge or ≤ 5 mm CBDS (29.9 vs. 8.3%; p < 0.001).

DISCUSSION

Spontaneous migration of small CBDS is a frequent event, and ≤ 5 mm size and a delay in ERCP > 7 days represent predictive factors for it. We suggest that CBDS ≤ 5 mm should not undergo immediate removal and this fact would allow reducing the rate of unnecessary ERCP with their related complications. Prospective studies are needed to confirm these results and demonstrate the safety of a conservative management in this setting.

Noninvasive Imaging Prior to Biliary Interventions

Noninvasive imaging is a crucial and initial step in the diagnostic algorithm of patients with suspected biliary pathology and directs the subsequent diagnostic and therapeutic workup, including the endoluminal and percutaneous biliary interventions. This article reviews the current noninvasive imaging methods for the evaluation of biliary system and further discusses their roles in the diagnostic workup of different biliary disease.

Management of cholelithiasis with choledocholithiasis: Endoscopic and surgical approaches

Gallstone disease and complications from gallstones are a common clinical problem. The clinical presentation ranges between being asymptomatic and recurrent attacks of biliary pain requiring elective or emergency treatment. Bile duct stones are a frequent condition associated with cholelithiasis. Amidst the total cholecystectomies performed every year for cholelithiasis, the presence of bile duct stones is 5%-15%; another small percentage of these will develop common bile duct stones after intervention. To avoid serious complications that can occur in choledocholithiasis, these stones should be removed. Unfortunately, there is no consensus on the ideal management strategy to perform such. For a long time, a direct open surgical approach to the bile duct was the only unique approach. With the advent of advanced endoscopic, radiologic, and minimally invasive surgical techniques, however, therapeutic choices have increased in number, and the management of this pathological situation has become multidisciplinary. To date, there is agreement on preoperative management and the need to treat cholelithiasis with choledocholithiasis, but a debate still exists on how to cure the two diseases at the same time. In the era of laparoscopy and mini-invasiveness, we can say that therapeutic approaches can be performed in two sessions or in one session. Comparison of these two approaches showed equivalent success rates, postoperative morbidity, stone clearance, mortality, conversion to other procedures, total surgery time, and failure rate, but the one-session treatment is characterized by a shorter hospital stay, and more cost benefits. The aim of this review article is to provide the reader with a general summary of gallbladder stone disease in association with the presence of common bile duct stones by discussing their epidemiology, clinical and diagnostic aspects, and possible treatments and their advantages and limitations.

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.

Making the invisible visible: improving conspicuity of noncalcified gallstones using dual-energy CT

PURPOSE

To determine whether virtual monochromatic imaging (VMI) increases detectability of noncalcified gallstones on dual-energy CT (DECT) compared with conventional CT imaging.

MATERIALS AND METHODS

This retrospective IRB-approved, HIPAA-compliant study included consecutive patients who underwent DECT of the abdomen in the Emergency Department during a 30-month period (July 1, 2013-December 31, 2015), with a comparison US or MR within 1-year. 51 patients (36F, 15M; mean age 52 years) fulfilled the inclusion criteria. All DECT were acquired on a dual-source 128 × 2 slice scanner using either 80/Sn140 or 100/Sn140 kVp pairs. Source images at high and low kVp were used for DE post-processing with VMI. Within 3 mm reconstructed images, regions of interest of 0.5 cm² were placed on noncalcified gallstones and bile to record hounsfield units (HU) at VMI energy levels ranging between 40 and 190 keV.

RESULTS

Noncalcified gallstones uniformly demonstrated lowest HU at 40 keV and increase at higher keV; the HU of bile varied at higher keV. Few of the noncalcified stones are visible at 70 keV (simulating a conventional 120 kVp scan), with measured contrast (bile-stone HU difference) <10 HU in 78%, 10-20 HU in 20%, and >20 HU in 2%. Contrast was maximal at 40 keV, where 100% demonstrated >20 HU difference from surrounding bile, 75% >44 HU difference, and 50% >60 HU difference. A paired t test demonstrated a significant difference (p < 0.0001) between this stone-bile contrast at 40 vs. 70 keV and 70 vs. 190 keV.

CONCLUSION

Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

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.

Biliary strictures and masses: an expanded differential diagnosis

Biliary strictures and masses are commonly a result of cholangiocarcinoma. However, there are several congenital, infectious, inflammatory, autoimmune, iatrogenic, and neoplastic etiologies that should also be considered in the differential diagnosis. Knowledge of the key imaging and clinical findings will aid in facilitating the diagnosis and treatment.

Noninvasive Imaging of the Biliary Tree for the Interventional Radiologist

Patients with suspected biliary tract disease often pose a diagnostic challenge to the clinician and radiologist. Although advances across all imaging modalities, including ultrasound, computed tomography, and magnetic resonance, have improved our diagnostic accuracy for biliary disease, many of the imaging findings remain nonspecific. Recognition of key imaging findings combined with knowledge and understanding of the clinical context is essential to piecing together a diagnosis and guiding management for patients with biliary disease. Although there is a wide range of biliary pathology, interventional radiologists most commonly play a role in the management of biliary obstruction and leak.

Diagnostic value of magnetic resonance cholangiopancreatography in choledocholithiasis

AIM: To evaluate the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) in patients with choledocholithiasis.

METHODS: We systematically searched MEDLINE, EMBASE, Web of Science, and Cochrane databases for studies reporting on the sensitivity, specificity and other accuracy measures of diagnostic effectiveness of MRCP for detection of common bile duct (CBD) stones. Pooled analysis was performed using random effects models, and receiver operating characteristic curves were generated to summarize overall test performance. Two reviewers independently assessed the methodological quality of studies using standards for reporting diagnostic accuracy and quality assessment for studies of diagnostic accuracy tools.

RESULTS: A total of 25 studies involving 2310 patients with suspected choledocholithiasis and 738 patients with CBD stones met the inclusion criteria. The average inter-rater agreement on the methodological quality checklists was 0.96. Pooled analysis of the ability of MRCP to detect CBD stones showed the following effect estimates: sensitivity, 0.90 (95%CI: 0.88-0.92, χ² = 65.80; P < 0.001); specificity, 0.95 (95%CI: 0.93-1.0, χ² = 110.51; P < 0.001); positive likelihood ratio, 13.28 (95%CI: 8.85-19.94, χ² = 78.95; P < 0.001); negative likelihood ratio, 0.13 (95%CI: 0.09-0.18, χ² = 6.27; P < 0.001); and diagnostic odds ratio, 143.82 (95%CI: 82.42-250.95, χ² = 44.19; P < 0.001). The area under the receiver operating characteristic curve was 0.97. Significant publication bias was not detected (P = 0.266).

CONCLUSION: MRCP has high diagnostic accuracy for the detection of choledocholithiasis. MRCP should be the method of choice for suspected cases of CBD stones.

Detectability of choledocholithiasis on CT: The effect of positive intraduodenal enteric contrast on portovenous contrast-enhanced studies

BACKGROUND/AIM

To retrospectively assess the accuracy of intravenous (IV) contrast-enhanced multidetector CT (MDCT) in choledocholithiasis detectability, in the presence and absence of positive intraduodenal contrast.

PATIENTS AND METHODS

Over a 3-year period, patients in whom endoscopic retrograde cholangiopancreatography (ERCP) was performed within a week from a portovenous (PV)-enhanced abdominal CT were identified. The final cohort consisted of 48 CT studies in which the entire common bile duct (CBD) length was visualized (19 males, 29 females; mean age, 68 years). We identified two groups according to the absence (n = 31) or presence (n = 17) of positive intraduodenal contrast. CT section thickness ranged from 1.25 to 5 mm. Two radiologists, blinded to clinical information and ERCP results, independently evaluated the CT images. Direct CBD stone visualization was assessed according to previously predefined criteria, correlating with original electronic CT reports and using ERCP findings as the reference standard. A third reader retrospectively reviewed all discordant results. The diagnostic performances of both observers and interobserver agreement were calculated for both groups.

RESULTS

77%-88% sensitivity, 50%-71% specificity, and 71%-74% accuracy were obtained in the group without positive intraduodenal contrast, versus 50%-80% sensitivity, 57%-71% specificity, and 59%-71% accuracy in the group with positive intraduodenal contrast. With the exception of the positive predictive value (PPV), all diagnostic performance parameters decreased in the positive intraduodenal contrast group, mostly affecting the negative predictive value (NPV) (71%-78% vs 50%-67%).

CONCLUSION

PV-enhanced MDCT has moderate diagnostic performance in choledocholithiasis detection. A trend of decreasing accuracy was noted in the presence of positive intraduodenal contrast.

Diagnosis and management of choledocholithiasis in the golden age of imaging, endoscopy and laparoscopy

Biliary lithiasis is an endemic condition in both Western and Eastern countries, in some studies affecting 20% of the general population. In up to 20% of cases, gallbladder stones are associated with common bile duct stones (CBDS), which are asymptomatic in up to one half of cases. Despite the wide variety of examinations and techniques available nowadays, two main open issues remain without a clear answer: how to cost-effectively diagnose CBDS and, when they are finally found, how to deal with them. CBDS diagnosis and management has radically changed over the last 30 years, following the dramatic diffusion of imaging, including endoscopic ultrasound (EUS) and magnetic resonance cholangiography (MRC), endoscopy and laparoscopy. Since accuracy, invasiveness, potential therapeutic use and cost-effectiveness of imaging techniques used to identify CBDS increase together in a parallel way, the concept of “risk of carrying CBDS” has become pivotal to identifying the most appropriate management of a specific patient in order to avoid the risk of “under-studying” by poor diagnostic work up or “over-studying” by excessively invasive examinations. The risk of carrying CBDS is deduced by symptoms, liver/pancreas serology and ultrasound. “Low risk” patients do not require further examination before laparoscopic cholecystectomy. Two main “philosophical approaches” face each other for patients with an “intermediate to high risk” of carrying CBDS: on one hand, the “laparoscopy-first” approach, which mainly relies on intraoperative cholangiography for diagnosis and laparoscopic common bile duct exploration for treatment, and, on the other hand, the “endoscopy-first” attitude, variously referring to MRC, EUS and/or endoscopic retrograde cholangiography for diagnosis and endoscopic sphincterotomy for management. Concerning CBDS diagnosis, intraoperative cholangiography, EUS and MRC are reported to have similar results. Regarding management, the recent literature seems to show better short and long term outcome of surgery in terms of retained stones and need for further procedures. Nevertheless, open surgery is invasive, whereas the laparoscopic common bile duct clearance is time consuming, technically demanding and involves dedicated instruments. Thus, although no consensus has been achieved and CBDS management seems more conditioned by the availability of instrumentation, personnel and skills than cost-effectiveness, endoscopic treatment is largely preferred worldwide.

Pancreatitis-imaging approach

Pancreatitis is defined as the inflammation of the pancreas and considered the most common pancreatic disease in children and adults. Imaging plays a significant role in the diagnosis, severity assessment, recognition of complications and guiding therapeutic interventions. In the setting of pancreatitis, wider availability and good image quality make multi-detector contrast-enhanced computed tomography (MD-CECT) the most used imaging technique. However, magnetic resonance imaging (MRI) offers diagnostic capabilities similar to those of CT, with additional intrinsic advantages including lack of ionizing radiation and exquisite soft tissue characterization. This article reviews the proposed definitions of revised Atlanta classification for acute pancreatitis, illustrates a wide range of morphologic pancreatic parenchymal and associated peripancreatic changes for different types of acute pancreatitis. It also describes the spectrum of early and late chronic pancreatitis imaging findings and illustrates some of the less common types of chronic pancreatitis, with special emphasis on the role of CT and MRI.

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.

Bile Duct Strictures Caused by Solid Masses: MR in Differential Diagnosis and as a Prognostic Tool to Plan the Endoscopic Treatment

The aim of the study was to assess how realiable is differential diagnosis and prognosis for endoscopic treatment with MR signal characteristics as the qualitative parameter and magnetic resonance cholangiopancreatography (MRCP) images in cases of bile duct obstructions caused by solid masses. Material and Methods. Retrospective study of MR and MRCP images in 80 patients (mean age 58 ys) was conducted. Mean signal intensity ratio (SIR) from planar MR images and MRCP linear measurements were compared between benign and malignant lesions and in groups including the size and number of stents placed during ERCP (< 10 F <) in 51 cases in which ERCP was performed. Results. Significantly higher SIR values were encountered in malignant lesions in T2W images (r = 0,0003) and STIR T2W images (r = 0,0002). Malignant lesions were characterised by longer strictures (r = 0,0071) and greater proximal biliary duct dilatation (r = 0,0024). High significance for predicting ERCP conditions was found with mean SIR in STIR T2W images and stricture length. Conclusion. Probability of malignancy of solid lesions obstructing biliary duct increased with higher SIR in T2W images and with longer strictures. Passing the stricture during ERCP treatment was easier and more probable in cases of shorter strictures caused by lesions with higher SIR in STIR T2W images.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular findings.

Reconstruction of the portal vein with 64-slice spiral CT of bile duct obstruction

The aim of this study was to evaluate 64-slice spiral CT image reconstruction of the portal vein in biliary obstruction. A total of 34 clinical patients with biliary obstruction were confirmed by 64-slice spiral CT scanning with portal venous phase multi-planar reconstruction (MPR) of the biliary tract, curved planar reconstruction (CPR), thin-slab minimum-intensity projection (TS-MinIP) and maximum intensity projection (MIP). The reconstructed images were reviewed to further assess the position and cause of the biliary obstruction and to judge the accuracy of diagnosis. The 64-slice spiral CT image reconstruction of the biliary obstructions determined the causes with an accuracy of 88.2% (30/34) and identified the location of the obstruction with an accuracy of 100%. A 64-slice spiral CT reconstructed image of the portal bile duct lesions was generated, which indicated the lesion morphology, location and anatomical relationship with surrounding tissues, secondary biliary stricture and the degree of expansion and is of great clinical value in the characterization and preoperative evaluation of biliary disease.

Pre-ERCP imaging of the bile duct and gallbladder

Advances in biliary imaging have improved making accurate diagnoses of the presence and causes of biliary obstruction. Abdominal ultrasound is a useful screening tool because it is highly specific for choledocholithiasis. New developments in CT and MRI have also been useful in the diagnosis of biliary disease. Although diagnosis of biliary disease can be achieved in a noninvasive manner, there are limitations to modern MRI and CT cholangiographic techniques; their use may not be necessary or cost effective. MRI and CT imaging of the biliary tract provides opportunities for less-invasive diagnostic techniques but should be used judiciously before interventional endoscopy.

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.

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.

Initial assessment of dual-energy CT in patients with gallstones or bile duct stones: can virtual nonenhanced images replace true nonenhanced images?

OBJECTIVE

The purpose of our study was to investigate whether virtual nonenhanced images can replace true nonenhanced images for the evaluation of biliary stones and to compare two virtual nonenhanced images obtained from dual-energy data sets during the late arterial phase (LAP) and portal venous phase (PVP) with true nonenhanced images.

MATERIALS AND METHODS

One hundred patients with gallstones (n = 77) or bile duct stones (n = 23) who had undergone dual-source dual-energy CT (using 80kVp and 140kVp with the ratio of dose-partitioning, 1:1.3), were included. The CT numbers for the stone, liver, and bile; stone size; and image noise were assessed for each image set. The conspicuity and size of the stones, image quality, and acceptability of the virtual nonenhanced images as a replacement for true nonenhanced images were assessed.

RESULTS

Virtual nonenhanced images from both LAP (VNE(LAP)) and PVP showed lower CT numbers for the stone and smaller stone size than did true nonenhanced images (p < 0.05). VNE(LAP) images failed to show stones in 16 patients (16%) with relatively radiolucent bile duct stones (< 78 HU) or small gallstones (< 9 mm(2), < 1.7 mm). There was no difference between the two virtual nonenhanced image sets except for the contrast-to-noise ratio of stone to bile and the image noise (CT numbers for the stone, liver, and muscle; stone size; and contrast-to-noise ratio of stone to liver, p = 1; the CT number for the bile, p = 0.1618; and effective dose, p = 0.7478). VNE(LAP) images were considered acceptable as a replacement for true nonenhanced images in 89% and 90% by reviewers 1 and 2, respectively.

CONCLUSION

Virtual nonenhanced images allow the detection of biliary stones with moderate accuracy, irrespective of the dual-energy contrast-enhanced phase. The detection of gallbladder stones of 9 mm(2) or smaller and of relatively radiolucent bile duct stones of 78 HU or lower is limited.

Negative predictive value of intravenous contrast-enhanced CT of the abdomen for patients presenting to the emergency department with undifferentiated upper abdominal pain

The purpose of this study is to calculate the negative predictive value (NPV) CT of the abdomen in patients presenting to the emergency department (ED) with undifferentiated upper abdominal pain. Approved by the hospital research ethics board, this retrospective study examined consecutive patients presenting to the ED with undifferentiated upper abdominal pain whose intravenous contrast-enhanced CT of the abdomen was reported as "normal" from June 2006-August 2010. Exclusion criteria included active malignancy, trauma, and known inflammatory bowel disease. True-negative (TN) vs. false-negative (FN) cases were categorized by consensus opinion of radiologist and emergency physician using a composite reference standard including clinical, laboratory, imaging, surgery, pathology, and patient self-reporting via phone questionnaire. The NPV was calculated with confidence intervals of 95%. The TN and FN groups were compared based on gender, age, site of pain, oral contrast use, and laboratory values. One hundred twenty-seven patients were included for analysis. The NPV was 64% (95% CI 55-72). The FN group had a higher proportion of patients with epigastric pain (p = 0.02) and a lower proportion of patients with left upper quadrant pain (p = 0.02). The WBC, lipase, and ALT were all higher in the FN group compared with the TN group. The most commonly missed pathologies were inflammatory conditions of the biliary tract and upper gastrointestinal systems. The NPV of CT for evaluation of undifferentiated upper abdominal pain in the ED was low at 64%. Physicians should consider this limitation and the commonly missed pathology when discharging patients with a "normal" CT report.

Diagnostic performance of multidetector CT for acute cholangitis: evaluation of a CT scoring method

OBJECTIVE

The aim of this study was to retrospectively assess the diagnostic performance of multidetector CT (MDCT) for the diagnosis of acute cholangitis using a new scoring method.

METHODS

Of 80 patients with suspected biliary disease who underwent biphasic CT and endoscopic retrograde cholangiography, 39 were diagnosed as having acute cholangitis (Group 1) and 41 patients were classified as suspected biliary disease (Group 2). 100 age-matched patients without evidence of biliary disease were selected randomly as a control group (Group 3). Each patient's axial scan was scored by two independent radiologists for the extent of transient hepatic attenuation difference, the presence of biliary dilatation and identification of a biliary obstructive lesion. The difference in the scores among the three groups was evaluated and the optimal cut-off score for the diagnosis of acute cholangitis was determined. Interobserver agreement was also evaluated.

RESULTS

The total scores (mean ± standard deviation) for Groups 1, 2 and 3 were 7.0 ± 2.0, 4.4 ± 2.4 and 0.9 ± 1.2, respectively, for Reviewer 1 and 7.2 ± 2.7 and 0.7 ± 1.1, respectively, for Reviewer 2. Significant differences were found for the subscores and the total scores among the three groups (p < 0.001). Using a cut-off score of ≥ 5, the sensitivity and specificity for diagnosing acute cholangitis were 84.6% and 83.7%, respectively, for Reviewer 1 and 89.7% and 83.7%, respectively, for Reviewer 2. Agreement for the subscores between readers was good to excellent (κ = 0.74-0.86).

CONCLUSION

Based on dynamic MDCT and the described CT scoring method, the diagnosis of acute choangitis can be made with high sensitivity and specificity.

Comparison of three-dimensional negative-contrast CT cholangiopancreatography with three-dimensional MR cholangiopancreatography for the diagnosis of obstructive biliary diseases

PURPOSE

The purpose of our study was to compare three-dimensional (3D) negative-contrast CT cholangiopancreatography (3D-nCTCP) with 3D MR cholangiopancreatography (3D-MRCP) for the diagnosis of obstructive biliary diseases.

MATERIALS AND METHODS

3D-nCTCP and 3D-MRCP were performed on seventy clinically documented obstructive biliary diseases patients. The accuracy of each technique in determining the location and cause of biliary obstruction was evaluated compared with the final clinical diagnoses.

RESULTS

Both methods achieved 100% of accuracy in the diagnosis of the presence and location of biliary obstruction, and had a similar sensitivity, specificity, accuracy in differentiating benign from malignant biliary obstruction or calculous from noncalculous biliary obstruction (p>0.05). At 3D-nCTCP, six patients with stones were misinterpreted as cholangitis (N=2), papillitis (N=3), or bile duct adenocarcinoma (N=1); two metastases were mistaken as acute pancreatitis or pancreatic head carcinomas, and one intrahepatic cholangiocarcinoma was misled as bile duct adenoma. At 3D-MRCP, one small stone, one ampullary adenoma, and one intrahepatic cholangiocarcinoma were mistaken as cholangitis, ampullary stone, and intrahepatic bile duct stone, respectively, and three gallbladder carcinomas and another intrahepatic cholangiocarcinoma were misdiagnosed as hilar cholangiocarcinoma (N=3) or common hepatic duct stone (N=1); four metastases were mistaken as pancreatic head carcinomas (N=3) or distal cholangiocarcinoma (N=1). The overall accuracy in making specific diagnosis of the cause of biliary obstruction was 87.1% for 3D-nCTCP and 84.3% for 3D-MRCP, respectively, (p>0.05).

CONCLUSION

3D-nCTCP has the similar effects as 3D-MRCP for the diagnosis of biliary obstruction and, the location and the cause of biliary obstruction. In view of selected cases contraindications for MRI, 3D-nCTCP is a potential substitute.

MR imaging and CT of the biliary tract

Magnetic resonance (MR) imaging and computed tomography (CT) can be useful in the diagnosis of biliary disease, with both modalities allowing detailed evaluation of the biliary tract. Careful interrogation of the images is critical, regardless of modality. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section imaging. Smooth, concentric short-segment strictures favor a benign cause, whereas abrupt, eccentric long-segment strictures favor a malignancy. At MR imaging, extrabiliary entities such as crossing vessels or metallic clip artifact may mimic strictures and should not be mistaken for disease. A stone is the most common biliary filling defect and may occur in the absence of dilated ducts. Stones commonly have a lamellated, geometric shape and are found in a dependent portion of the duct. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Improved diagnosis of biliary disease can be achieved with a knowledge of the benefits and limitations of modern MR and CT cholangiographic techniques, including the use of biliary-excreted contrast material and of various postprocessing techniques. Familiarity with the radiologic appearances of the duct lumen, wall, and surrounding structures is also important for accurate image interpretation. The rapidly evolving technology for both MR imaging and CT of the biliary tract will continue to present radiologists with opportunities as well as challenges.

How many CT detector rows are necessary to perform adequate three dimensional visualization?

INTRODUCTION

The technical development of computer tomography (CT) imaging has experienced great progress. As consequence, CT data to be used for 3D visualization is not only based on 4 row CTs and 16 row CTs but also on 64 row CTs, respectively. The main goal of this study was to examine whether the increased amount of CT detector rows is correlated with improved quality of the 3D images.

MATERIAL AND METHODS

All CTs were acquired during routinely performed preoperative evaluation. Overall, there were 12 data sets based on 4 detector row CT, 12 data sets based on 16 detector row CT, and 10 data sets based on 64 detector row CT. Imaging data sets were transferred to the DKFZ Heidelberg using the CHILI teleradiology system. For the analysis all CT scans were examined in a blinded fashion, i.e. both the name of the patient as well as the name of the CT brand were erased. For analysis, the time for segmentation of liver, both portal and hepatic veins as well as the branching depth of portal veins and hepatic veins was recorded automatically. In addition, all results were validated in a blinded fashion based on given quality index.

RESULTS

Segmentation of the liver was performed in significantly shorter time (p<0.01, Kruskal-Wallis test) in the 16 row CT (median 479 s) compared to 4 row CT (median 611 s), and 64 row CT (median 670 s), respectively. The branching depth of the portal vein did not differ significantly among the 3 different data sets (p=0.37, Kruskal-Wallis test). However, the branching depth of the hepatic veins was significantly better (p=0.028, Kruskal-Wallis test) in the 4 row CT and 16 row CT compared to 64 row CT. The grading of the quality index was not statistically different for portal veins and hepatic veins (p=0.80, Kruskal-Wallis test). Even though the total quality index was better for the vessel tree based on 64 row CT data sets (mean scale 2.6) compared to 4 CT row data (mean scale 3.25) and 16 row CT data (mean scale 3.0), these differences did not reach statistical difference (p=0.53, Kruskal-Wallis test).

CONCLUSION

Even though 3D visualization is useful in operation planning, the quality of the 3D images appears to be not dependent of the number of CT detector rows.