Differentiation of adenomyomatosis of the gallbladder from early-stage, wall-thickening-type gallbladder cancer using high-resolution ultrasound

Value of high frame rate contrast enhanced ultrasound in gallbladder wall thickening in non-acute setting

BACKGROUND

Ultrasound (US) has been widely used in screening and differential diagnosis of gallbladder wall thickening (GWT). However, the sensitivity and specificity for diagnosing wall-thickening type gallbladder cancer are limited, leading to delayed treatment or overtreatment. We aim to explore the value of high frame rate contrast enhanced ultrasound (H-CEUS) in distinguishing wall-thickening type gallbladder cancer (malignant) from GWT mimicking malignancy (benign).

METHODS

This retrospective study enrolled consecutive patients with non-acute GWT who underwent US and H-CEUS examination before cholecystectomy. Clinical information, US image and H-CEUS image characteristics between malignant and benign GWT were compared. The independent risk factors for malignant GWT on H-CEUS images were selected by multivariate logistic regression analysis. The diagnostic performance of H-CEUS in determining malignant GWT was compared with that of the gallbladder reporting and data system (GB-RADS) score.

RESULTS

Forty-six patients included 30 benign GWTs and 16 malignant GWTs. Only mural layering and interface with liver on US images were significantly different between malignant and benign GWT (P < 0.05). Differences in enhancement direction, vascular morphology, serous layer continuity, wash-out time and mural layering in the venous phase of GWT on H-CEUS images were significant between malignant and benign GWT (P < 0.05). The sensitivity, specificity and accuracy of H-CEUS based on enhancement direction, vascular morphology and wash-out time in the diagnosis of malignant GWT were 93.75%, 90.00%, and 91.30%, respectively. However, the sensitivity, specificity and accuracy of the GB-RADS score were only 68.75%, 73.33% and 71.74%, respectively. The area under ROC curve (AUC) of H-CEUS was significantly higher than that of the GB-RADS score (AUC = 0.965 vs. 0.756).

CONCLUSIONS

H-CEUS can accurately detect enhancement direction, vascular morphology and wash-out time of GWT, with a higher diagnostic performance than the GB-RADS score in determining wall-thickening type gallbladder cancer. This study provides a novel imaging means with high accuracy for the diagnosis of wall-thickening type gallbladder cancer, thus may be better avoiding delayed treatment or overtreatment.

Sonographic "Cervix Sign": A New Ancillary Sign of Gallbladder Neck Malignancy

Background

The differentiation of benign and malignant gallbladder wall thickening is challenging. The purpose of this study is to evaluate a new sonographic sign, "cervix sign" for differentiation of benign and malignant gallbladder neck thickening.

Methods

This retrospective study comprised consecutive patients with gallbladder neck thickening who underwent sonography between August 2019 and December 2021. The presence of "cervix sign" was assessed by two radiologists independently.

Results

Sixty-five patients had gallbladder neck thickening (28 malignant and 37 benign). The sonographic "cervix sign" was present in 18 (64%) patients with malignant thickening and in only one (2.7%) patient with benign thickening (P = 0.0001). The mean wall thickness was greater, and symmetric wall thickening and liver metastases were more common in malignant thickening with "cervix sign" (without reaching statistical significance). There was substantial agreement (kappa = 0.78) between the two observers for the cervix sign.

Conclusion

Sonographic "cervix sign" is a useful ancillary feature of gallbladder neck cancer.

Usefulness of contrast-enhanced ultrasonography for biliary tract disease

Conventional ultrasonography (US) for biliary tract disease shows high time and spatial resolution. In addition, it is simple and minimally invasive, and is selected as a first-choice examination procedure for biliary tract disease. Currently, contrast-enhanced US (CEUS), which facilitates the more accurate assessment of lesion blood flow in comparison with color and power Doppler US, is performed using a second-generation ultrasonic contrast agent. Such agents are stable and provide a timeline for CEUS diagnosis. Gallbladder lesions are classified into three types: gallbladder biliary lesion (GBL), gallbladder polypoid lesion (GPL), and gallbladder wall thickening (GWT). Bile duct lesions can also be classified into three types: bile duct biliary lesion (BBL), bile duct polypoid lesion (BDPL), and bile duct wall thickening (BDWT). CEUS facilitates the differentiation of GBL/BBL from tumorous lesions based on the presence or absence of blood vessels. In the case of GPL, it is important to identify a vascular stalk attached to the lesion. In the case of GWT, the presence or absence of a non-contrast-enhanced area, the Rokitansky-Aschoff sinus, and continuity of a contrast-enhanced gallbladder wall layer are important for differentiation from gallbladder cancer. In the case of BDWT, it is useful to evaluate the contour of the contrast-enhanced medial layer of the bile duct wall for differentiating IgG4-related sclerosing cholangitis from primary sclerosing cholangitis. CEUS for ampullary carcinoma accurately reflects histopathological findings of the lesion. Evaluating blood flow in the lesion, continuity of the gallbladder wall, and contour of the bile duct wall via CEUS provides useful information for the diagnosis of biliary tract disease.

Effect of different lymph node dissection methods on the number of lymph nodes detected and prognosis in gallbladder cancer

At present, the extent of lymph node dissection (LND) for radical gallbladder cancer (GBC) is still controversial, and there is no evidence that LND improves prognosis, however, the latest guidelines for GBC recommend that removal of more than 6 lymph nodes facilitates staging of regional lymph nodes. The aim of this study is to investigate the effect of different LND methods on the number of lymph nodes detected and assess the prognostic factors during radical resection of GBC. This study retrospectively analyzed 133 patients (46 men and 87 women; average age: 64.01, range: 40-83 years) who underwent radical resection of GBC in a single center between July 2017 and July 2022, of which 41 underwent fusion lymph node dissection (FLND) and 92 underwent standard lymph node dissection (SLND). Baseline data, surgical results, number of LNDs, and follow-up data were analyzed. Each patient was followed up every 3 months. The total number of lymph nodes detected after the operation was 12.00 ± 6.95 versus 6.10 ± 4.71 (P < .05). The number of positive lymph nodes detected was (mean) 1.85 versus 0.78 and (percentage) 15.45% versus 12.83% (P < .05). Postoperative complications (8 vs 23, P > .05). The progression-free survival was 13 versus 8 months, the median survival time was 17 versus 9 months (P < .05). This study concluded that FLND can increase the detection rate of total lymph nodes and positive lymph nodes after surgery, which can prolong the survival time of patients.

Gallbladder polyps and adenomyomatosis

Incidental findings are commonly detected during examination of the gallbladder. Differentiating benign from malignant lesions is critical because of the poor prognosis associated with gallbladder malignancy. Therefore, it is important that radiologists and sonographers are aware of common incidental gallbladder findings, which undoubtedly will continue to increase with growing medical imaging use. Ultrasound is the primary imaging modality used to examine the gallbladder and biliary tree, but contrast-enhanced ultrasound and MRI are increasingly used. This review article focuses on two common incidental findings in the gallbladder; adenomyomatosis and gallbladder polyps. The imaging features of these conditions will be reviewed and compared between radiological modalities, and the pathology, epidemiology, natural history, and management will be discussed.

RadFormer: Transformers with global-local attention for interpretable and accurate Gallbladder Cancer detection

We propose a novel deep neural network architecture to learn interpretable representation for medical image analysis. Our architecture generates a global attention for region of interest, and then learns bag of words style deep feature embeddings with local attention. The global, and local feature maps are combined using a contemporary transformer architecture for highly accurate Gallbladder Cancer (GBC) detection from Ultrasound (USG) images. Our experiments indicate that the detection accuracy of our model beats even human radiologists, and advocates its use as the second reader for GBC diagnosis. Bag of words embeddings allow our model to be probed for generating interpretable explanations for GBC detection consistent with the ones reported in medical literature. We show that the proposed model not only helps understand decisions of neural network models but also aids in discovery of new visual features relevant to the diagnosis of GBC. Source-code is available at https://github.com/sbasu276/RadFormer.

Incidental Findings of Gallbladder and Bile Ducts-Management Strategies: General Aspects, Gallbladder Polyps and Gallbladder Wall Thickening-A World Federation of Ultrasound in Medicine and Biology (WFUMB) Position Paper

The World Federation of Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings with a series of position papers to give advice on characterization and management. The biliary system (gallbladder and biliary tree) is the third most frequent site for incidental findings. This first part of the position paper on incidental findings of the biliary system is related to general aspects, gallbladder polyps and other incidental findings of the gallbladder wall. Available evidence on prevalence, diagnostic work-up, malignancy risk, follow-up and treatment is summarized with a special focus on ultrasound techniques. Multiparametric ultrasound features of gallbladder polyps and other incidentally detected gallbladder wall pathologies are described, and their inclusion in assessment of malignancy risk and decision- making on further management is suggested.

A Case of Early-Stage Gallbladder Cancer, Positive for ALDH1A1, Which Arose from Adenomyomatosis of the Gallbladder

Adenomyomatosis (ADM) of the gallbladder is a condition characterized by the proliferation of Rokitansky–Aschoff sinus (RAS), in which the epithelium of the gallbladder extends into the muscular layer, causing a thickening of the gallbladder wall. Although ADM is generally considered not to be a precancerous lesion of gallbladder cancer, there are some reports of cases of gallbladder cancer from ADM. Therefore, the relationship between ADM and gallbladder cancer remains controversial. We herein report a case of early-stage gallbladder cancer, BilIN3 (high grade), arising from ADM that was positive for ALDH1A1, an important marker of stem cells and cancer stem cells.

A Review of the Etiology and Epidemiology of Gallbladder Cancer: What You Need to Know

Gallbladder cancer (GBC) is the sixth most prevalent cancer of the gastrointestinal system but the most prevalent cancer of the biliary tract. This tumor is a highly fatal condition. The importance of early diagnosis cannot be overstated because GBC develops quietly with late detection. Several genetic and environmental variables have been associated with the onset of GBC. Cholelithiasis and chronic inflammation from the biliary tract and parasite infections are prime examples of environmental factors that significantly influence the development of GBC. Abnormal pancreaticobiliary duct junction and biliary cysts are examples of congenital causes. In the past decade, new imaging technologies and a more radical and aggressive surgical approach have improved patient outcomes and aided prolonged survival for GBC patients. This review article focuses on the epidemiology of GBC, its risk factors, and clinical characteristics.

Gallbladder reporting and data system (GB-RADS) for risk stratification of gallbladder wall thickening on ultrasonography: an international expert consensus

The Gallbladder Reporting and Data System (GB-RADS) ultrasound (US) risk stratification is proposed to improve consistency in US interpretations, reporting, and assessment of risk of malignancy in gallbladder wall thickening in non-acute setting. It was developed based on a systematic review of the literature and the consensus of an international multidisciplinary committee comprising expert radiologists, gastroenterologists, gastrointestinal surgeons, surgical oncologists, medical oncologists, and pathologists using modified Delphi method. For risk stratification, the GB-RADS system recommends six categories (GB-RADS 0-5) of gallbladder wall thickening with gradually increasing risk of malignancy. GB-RADS is based on gallbladder wall features on US including symmetry and extent (focal vs. circumferential) of involvement, layered appearance, intramural features (including intramural cysts and echogenic foci), and interface with the liver. GB-RADS represents the first collaborative effort at risk stratifying the gallbladder wall thickening. This concept is in line with the other US-based risk stratification systems which have been shown to increase the accuracy of detection of malignant lesions and improve management.

Grayscale ultrasonography findings for characterization of gallbladder wall thickening in non-acute setting: a systematic review and meta-analysis

BACKGROUND

The accurate characterization of gallbladder wall thickening (GWT) into benign or malignant on ultrasound (US) is a significant challenge.

METHODS

We searched the MEDLINE and EMBASE databases for studies reporting two-dimensional grayscale US in benign and malignant GWT. The pooled prevalence was calculated using a generalized linear mixed method with a random-effects model. The pooled sensitivity and specificity were calculated using a bivariate random-effects model.

RESULTS

Of the 7309 studies screened by titles, 73 studies with 18,008 patients were included. The most common findings in xanthogranulomatous cholecystitis (XGC) were lack of wall disruption and intramural hypoechoic nodules while adenomyomatosis (ADM) was frequently associated with intramural cysts and intramural echogenic foci. Echogenic foci, lack of gallbladder wall disruption, and hypoechoic nodules had a sensitivity of 89%, 77%, and 66% and specificity of 86%, 51%, and 80%, respectively for the diagnosis of benign GWT. Focal thickening and indistinct liver interface had a sensitivity of 75% and 55% and specificity of 64% and 69%, respectively for the diagnosis of malignant GWT.

CONCLUSION

intramural features (echogenic foci, hypoechoic nodules), gallbladder wall disruption, and liver interface are useful US features for the characterization of GWT.

The Role of Fine Needle Aspiration Cytology in the Diagnosis of Gallbladder Cancer: A Systematic Review

Gallbladder cancer is the most common malignancy of the biliary tract. When diagnosed in an advanced stage it has a very poor prognosis. Therefore, early diagnosis and thorough assessment of a suspicious gallbladder polyp is essential to improve survival rate. The aim of this systematic review is to assess the role of fine needle aspiration cytology (FNAC) in the management of gallbladder cancer. For that purpose, a systematic review was carried out in the MEDLINE, EMBASE, Cochrane, Scopus and Google Scholar databases between 1 July 2004 and 22 April 2021. Six studies with 283 patients in total were included. Pooled sensitivity and specificity of FNAC were 0.85 and 0.94, respectively, while the area under the calculated summary receiver operating characteristic (SROC curve (AUC) was 0.98. No complications were reported. Based on the high diagnostic performance of FNAC in the assessment of gallbladder masses, we suggest that every suspicious mass should be evaluated further with FNAC to facilitate the most appropriate management.

How Can We Manage Gallbladder Lesions by Transabdominal Ultrasound?

The most important role of ultrasound (US) in the management of gallbladder (GB) lesions is to detect lesions earlier and differentiate them from GB carcinoma (GBC). To avoid overlooking lesions, postural changes and high-frequency transducers with magnified images should be employed. GB lesions are divided into polypoid lesions (GPLs) and wall thickening (GWT). For GPLs, classification into pedunculated and sessile types should be done first. This classification is useful not only for the differential diagnosis but also for the depth diagnosis, as pedunculated carcinomas are confined to the mucosa. Both rapid GB wall blood flow (GWBF) and the irregularity of color signal patterns on Doppler imaging, and heterogeneous enhancement in the venous phase on contrast-enhanced ultrasound (CEUS) suggest GBC. Since GWT occurs in various conditions, subdividing into diffuse and focal forms is important. Unlike diffuse GWT, focal GWT is specific for GB and has a higher incidence of GBC. The discontinuity and irregularity of the innermost hyperechoic layer and irregular or disrupted GB wall layer structure suggest GBC. Rapid GWBF is also useful for the diagnosis of wall-thickened type GBC and pancreaticobiliary maljunction. Detailed B-mode evaluation using high-frequency transducers, combined with Doppler imaging and CEUS, enables a more accurate diagnosis.

Surgical Choice for Different Types of Gallbladder Adenomyomatosis: An Initial Experience of 20 Years Laparoscopic Cholecystectomy

OBJECTIVES

The objective of this study was to compare the difference of clinical biochemical statistics in different types of gallbladder adenomyomatosis (GA). To investigate the different effects of patients between the 3 different types of GA.

MATERIALS AND METHODS

Retrospective analysis of the clinical data of the adenomyomatosis patients that come from our hospital between 2010 to 2018. According to the preoperative image (all cases are performed as elective surgery), it could be divided into 3 groups: group A: fundal (localized) type; group B: segmental type; group C: diffuse type. The number of each group is 136, 27, 17. We analyze the biochemical statistics (total bilirubin, direct bilirubin, serum bile acid, alanine aminotransferase, aspartate aminotransferase, cholinesterase, etc.) of the 3 groups to explore the difference in operative mode, operative time and prognosis between these 3 groups.

RESULTS

(1) In the liver function statistics, aspartate aminotransferase has the statistical significance (F=4.974, P=0.012); (2) And the diffuse adenomyomatosis might have a higher bile acid (F=6.048, P=0.005); (3) The segmental and diffuse adenomyomatosis is easier to be combined with stones (F=19.226, P<0.001); (4) The fundal adenomyomatosis seems to have a better prognosis: fewer hospital stay (F=4.519, P=0.018), fewer drainage time (F=6.575, P=0.004) and fewer complications (χ=29.429, P<0.001).

CONCLUSIONS

GA is a disease characterized by epithelial proliferation and hypertrophy of the muscles of the gallbladder wall with an outpouching of the mucosa into or through the thickened muscular layer and cannot be regarded as a precancerous lesion based on available evidence. As for asymptomatic GA, conservative treatment is recommended with ultrasound examinations twice a year. The fundal type GA can be treated by partial laparoscopic cholecystectomy. The segmental and diffuse-type should undergo a total laparoscopic cholecystectomy.

Gallbladder polyps ultrasound: what the sonographer needs to know

Gallbladder polyps are protuberances of the gallbladder wall projecting into the lumen. They are usually incidentally found during abdominal sonography or diagnosed on histopathology of a surgery specimen, with an estimated prevalence of up to 9.5% of patients. Gallbladder polyps are not mobile and do not demonstrate posterior acoustic shadowing; they may be sessile or pedunculated. Gallbladder polyps may be divided into pseudopolyps and true polyps. Pseudopolyps are benign and include cholesterolosis, cholesterinic polyps, inflammatory polyps, and localised adenomyomatosis. True gallbladder polyps can be benign or malignant. Benign polyps are most commonly adenomas, while malignant polyps are adenocarcinomas and metastases. There are also rare types of benign and malignant true gallbladder polyps, including mesenchymal tumours and lymphomas. Ultrasound is the first-choice imaging method for the diagnosis of gallbladder polyps, representing an indispensable tool for ensuring appropriate management. It enables limitation of secondary level investigations and avoidance of unnecessary cholecystectomies.

NIR/photoacoustic imaging of multitype gallbladder cancer using carboxyl/amino functionalized polymer dots

Gallbladder cancer has high incidence and mortality and a low early diagnosis rate and requires rapid and efficient diagnosis. Herein, carboxyl/amino functionalized polymer dots (Pdots) were designed to enhance cellular internalization and tumor accumulation. The prepared Pdots were 40-50 nm in diameter, contained no toxic metal, exhibited long circulation time and high stability, and produced strong NIR emission and photoacoustic signals. Different cellular uptake and distribution of functionalized Pdots in eight gallbladder cell lines were quantitatively investigated using flow cytometry and super-resolution microscopy. In vivo NIR fluorescence imaging showed that the functional Pdots had high accumulation in the tumor after 30 minutes of injection and remained there for up to 6 days. In addition, photoacoustic imaging found that the abundant blood vessels around the tumor microenvironment and Pdots entered the tumor through the blood vessels. Furthermore, a high heterogeneity of vascular networks was visualized in real-time and high resolution by probe-based confocal laser endomicroscopy imaging. These results offer a new avenue for the development of functional Pdots as a probe for multi-modal and multi-scale imaging of gallbladder cancer in small animals.

A narrative review of gallbladder adenomyomatosis: what we need to know

Gallbladder adenomyomatosis (GA) is increasingly encountered in clinical practice due to increasing use of imagings especially ultrasound (US). Clinicians need to know what is the implication of this condition and its proper management. GA is a degenerative and proliferative disease characterized by excessive epithelial proliferation associated with hypertrophy of muscularis propria. This leads to outpouchings of mucosa into or beyond the muscle layer forming intramural diverticula recognized as Rokitansky-Aschoff sinuses (RAS). Three types of GA are recognised: fundal, segmental and diffuse type. In fundal GA, there is focal thickening involving the GB fundus. In segmental GA, there is circumferential overgrowth of the GB wall that leads to formation of compartments. In diffuse GA, there is disseminated thickening and irregularity of the mucosa and muscularis. The pathogenesis of GA is unknown. It commonly occurs in middle age with equal sex distribution. Diagnosis of GA is by imagings showing thickened gallbladder wall containing cysts. Characteristic features are “comet-tail” artefacts and “twinkling” artefacts on US, “pearl-necklace sign” on magnetic resonance imaging (MRI) and “rosary sign” on computed tomography (CT). Cholecystectomy should be offered for symptomatic GA of any type. For asymptomatic GA, cholecystectomy may be considered for segmental type for its increased risk of malignancy and for diffuse type for its difficult visualization of any coexisting malignancy. Asymptomatic fundal GA can be safely observed with US. How frequent and how long should a fundal GA be monitored with US remains unknown. In case of diagnostic doubt, cholecystectomy should always be offered to avoid overlooked malignancy.

Imaging-based algorithmic approach to gallbladder wall thickening

Gallbladder (GB) wall thickening is a frequent finding caused by a spectrum of conditions. It is observed in many extracholecystic as well as intrinsic GB conditions. GB wall thickening can either be diffuse or focal. Diffuse wall thickening is a secondary occurrence in both extrinsic and intrinsic pathologies of GB, whereas, focal wall thickening is mostly associated with intrinsic GB pathologies. In the absence of specific clinical features, accurate etiological diagnosis can be challenging. The survival rate in GB carcinoma (GBC) can be improved if it is diagnosed at an early stage, especially when the tumor is confined to the wall. The pattern of wall thickening in GBC is often confused with benign diseases, especially chronic cholecystitis, xanthogranulomatous cholecystitis, and adenomyomatosis. Early recognition and differentiation of these conditions can improve the prognosis. In this minireview, the authors describe the patterns of abnormalities on various imaging modalities (conventional as well as advanced) for the diagnosis of GB wall thickening. This paper also illustrates an algorithmic approach for the etiological diagnosis of GB wall thickening and suggests a formatted reporting for GB wall abnormalities.

Gallbladder cancer revisited: the evolving role of a radiologist

Gallbladder cancer is the most common malignancy of the biliary tract. It is also the most aggressive biliary tumor with the shortest median survival duration. Complete surgical resection, the only potentially curative treatment, can be accomplished only in those patients who are diagnosed at an early stage of the disease. Majority (90%) of the patients present at an advanced stage and the management involves a multidisciplinary approach. The role of imaging in gallbladder cancer cannot be overemphasized. Imaging is crucial not only in detecting, staging, and planning management but also in guiding radiological interventions. This article discusses the role of a radiologist in the diagnosis and management of gallbladder cancer.

A Novel Staging System to Forecast the Cancer-Specific Survival of Patients With Resected Gallbladder Cancer

Objective: Gallbladder cancer (GBC) is one of the most aggressive malignant tumors, and there is no effective and convenient method for predicting cancer-specific survival (CSS). We aim to develop a novel nomogram staging system based on the positive lymph node ratio (pLNR) for GBC patients.

Methods:A total of 1,356 patients enrolled in the study. We evaluated the prognostic value of the pLNR and built a prognostic nomogram staging system based on the pLNR in the training cohort. The concordance index and calibration plots were used to evaluate model discrimination. The predictive accuracy and clinical value of the nomograms were measured by decision curve analysis (DCA). The CSS nomogram was further validated in an internal validation cohort.

Results:The pLNR was an independent prognostic factor for CSS based on Cox regression analyses. A prognostic nomogram that combined T classification, pLNR, M classification, histologic grade, live metastasis, and tumor size was formulated with a c-index of 0.763 (95% CI, 0.728–0.798), while the c-indexes for the staging system of AJCC 8th, 7th, and 6th for CSS prediction were 0.718, 0.718, and 0.717, respectively. The calibration curves showed perfect agreement. The DCA showed that the nomogram provided substantial clinical value. The nomogram (the AUCs for 1, 3, and 5 years were 0.693, 0.716, and 0.726, respectively,) showed high prognostic accuracy.

Conclusion:We have developed a formulated nomogram staging system based on the pLNR that allows more accurate individualized predictions of CSS for resected GBC patients than the AJCC staging systems.

Incidentally detected focal fundal gallbladder wall thickening: Differentiation contrast enhanced ultrasound features with high-resolution linear transducers

AIM

To investigate the value of contrast enhanced ultrasound with high resolution linear transducers (HF-CEUS) for differential diagnosis of focal fundal gallbladder (GB) wall thickening.

METHODS

A total of 32 patients with incidentally detected focal fundal GB wall thickening were included. After conventional B mode ultrasound (BMUS) examinations, HF-CEUS were performed with a 7.5-12 MHz 9L4 linear transducer (S2000 HELX OXANA unit, Siemens). Two radiologists independently reviewed the HF-CEUS enhancement patterns to determine the differential features between malignancy and benignity with a five-point confidence scale. The diagnostic accuracy of BMUS and HF-CEUS for GB wall thickening was compared. The final gold standard was surgery with histological examination.

RESULTS

Final diagnoses included GB adenocarcinoma (n = 16), adenomyomatosis (n = 12), Xanthogranulomatous (n = 2) and cholecystitis (n = 2). HF-CEUS features associated with GB adenocarcinoma including arterial phase inhomogeneous hyperenhancement, venous phase hypoenhancement and disruption of GB wall layer structure (P < 0.05). Two small (5 mm) liver metastasis were confirmed by HF-CEUS during the late phase liver sweep as hypoenhanced lesions. Nonenhanced Rokitansky-Aschoff sinuses were clearly observed in 83.3% focal adenomyomatosis. Overall sensitivity, specificity and accuracy for differentiation between malignant and benign focal fundal GB wall thickening of HF-CEUS and BMUS were 84.3% vs 53.1%, 90.6% vs 59.3% and 87.5% vs 56.2% (P < 0.005).

CONCLUSIONS

CEUS performed with high frequency linear transducers could be a useful alternative in the differential diagnosis of focal fundal GB wall thickening on conventional ultrasound.

Benign gallbladder diseases: Imaging techniques and tips for differentiating with malignant gallbladder diseases

Benign gallbladder diseases usually present with intraluminal lesions and localized or diffuse wall thickening. Intraluminal lesions of the gallbladder include gallstones, cholesterol polyps, adenomas, or sludge and polypoid type of gallbladder cancer must subsequently be excluded. Polyp size, stalk width, and enhancement intensity on contrast-enhanced ultrasound and degree of diffusion restriction may help differentiate cholesterol polyps and adenomas from gallbladder cancer. Localized gallbladder wall thickening is largely due to segmental or focal gallbladder adenomyomatosis, although infiltrative cancer may present similarly. Identification of Rokitansky-Aschoff sinuses is pivotal in diagnosing adenomyomatosis. The layered pattern, degree of enhancement, and integrity of the wall are imaging clues that help discriminate innocuous thickening from gallbladder cancer. High-resolution ultrasound is especially useful for analyzing the layering of gallbladder wall. A diffusely thickened wall is frequently seen in inflammatory processes of the gallbladder. Nevertheless, it is important to check for coexistent cancer in instances of acute cholecystitis. Ultrasound used alone is limited in evaluating complicated cholecystitis and often requires complementary computed tomography. In chronic cholecystitis, preservation of a two-layered wall and weak wall enhancement are diagnostic clues for excluding malignancy. Magnetic resonance imaging in conjunction with diffusion-weighted imaging helps to differentiate xathogranulomatous cholecystitis from gallbladder cancer by identifying the presence of fat and degree of diffusion restriction. Such distinctions require a familiarity with typical imaging features of various gallbladder diseases and an understanding of the roles that assorted imaging modalities play in gallbladder evaluations.

Evaluation of gallbladder wall thickening: a multimodality imaging approach

INTRODUCTION

Gallbladder (GB) wall thickening is a relatively common finding on imaging. While there are clear recommendations for the management of gallstones, GB wall thickening presents a significant challenge. Despite advances in radiological as well as endoscopic techniques, the ability to characterize GB wall thickening is still limited.

AREAS COVERED

This review summarizes the currently available literature on various imaging investigations to characterize GB wall thickening. This review also summarizes the differences between benign and malignant GB wall thickening based on available imaging modalities. Transabdominal ultrasonography is the first-line investigation for evaluation of GB wall thickening. However, further characterization requires additional imaging tests. Magnetic resonance imaging (MRI) with the use of gadolinium and diffusion-weighted sequence is the preferred modality for GB wall characterization.

EXPERT OPINION

The accurate characterization of GB wall thickening is a challenging task. The available imaging criteria allow differentiation of benign and malignant GB wall thickening with moderate accuracy. The advanced imaging techniques, including contrast enhanced ultrasound, contrast-enhanced endoscopic ultrasound, and shear wave elastography, continue to evolve. There is a need for a well-designed reporting system for GB wall thickening to ensure uniformity of reporting of imaging tests, especially in regions with a high prevalence of GB cancer.

Gallbladder Cancer: Imaging Appearance and Pitfalls in Diagnosis [Formula: see text]

Gallbladder cancer is an uncommon malignancy with an overall poor prognosis. The clinical and imaging presentation of gallbladder cancer often overlaps with benign disease, making diagnosis difficult. Gallbladder cancer is most easily diagnosed on imaging when it presents as a mass replacing the gallbladder. At this stage, the prognosis is usually poor. Recognizing the features of gallbladder cancer early in the disease can enable complete resection and improve prognosis. Recognition of the patterns of wall enhancement on computed tomography can help differentiate gallbladder cancer from benign disease. Gallbladder wall thickening without pericholecystic fluid presenting in an older patient with raised alkaline phosphatase should raise concern regarding gallbladder cancer. Gallbladder polyps in high-risk individuals need close surveillance or surgery as per guidelines. Small gallbladder cancers in the neck can present as biliary dilatation or cholecystitis, and careful examination of this area is needed to assess for lesion. The imaging appearance of gallbladder cancer is reviewed and supported by local institutional data. Features that differentiate it from its common mimics enabling earlier diagnosis are described.

B-mode ultrasonographic diagnosis in gallbladder wall thickening

Diseases associated with gallbladder wall thickening include benign entities such as adenomyomatosis of the gallbladder, acute and chronic cholecystitis, and hyperplasia associated with pancreaticobiliary maljunction, and also cancer. Unique conditions such as sclerosing cholecystitis and cholecystitis associated with immune checkpoint inhibitor treatment can also manifest as wall thickening, as in some systemic inflammatory conditions. Gallbladder cancer, the most serious disease that can show wall thickening, can be difficult to diagnose early and to distinguish from benign causes of wall thickening, contributing to a poor prognosis. Differentiating between xanthogranulomatous cholecystitis and gallbladder cancer with wall thickening can be particularly problematic. Cancers that thicken the wall while coexisting with benign lesions that cause wall thickening represent another potential pitfall. In contrast, some benign gallbladder lesions that can cause wall thickening, such as adenomyomatosis and acute cholecystitis, typically show characteristic ultrasonographic features that, together with clinical findings, permit easier diagnosis. In this review of the literature, we describe B-mode abdominal ultrasonographic diagnosis of gallbladder lesions showing wall thickening.

Optimization of diagnostic ultrasonography of the gallbladder based on own experience and literature

Although transabdominal imaging of the gallbladder has become a gold standard, new light should be shed on some aspects, which will prove useful in everyday practice. Therefore, based on our own experience and the available literature, we would like to draw attention to those elements of gallbladder ultrasound imaging which may increase its diagnostic efficacy. The paper draws attention to the difficulty in assessing certain anatomical structures, such as the inferior wall, the bottom and the region of the neck of the gallbladder, and offers ways to improve their imaging. We also emphasized the negative effects of duodenal and transverse colon (along with their contents) adhesion to the bottom of the gallbladder on the correct diagnosis. Due to the importance of size in the management strategy for detected gallbladder polyps, we suggest their measurement on an image enlarged with the zoom function. This technique also allows for an accurate assessment of the shape and echostructure of these lesions. An enlarged image of a polyp makes it possible to trace its behavior in time. We also remind that the hepatic wall of the gallbladder is the only site allowing for a reliable wall thickness measurement. We also pointed to the importance of changing patient’s position when assessing the mobility and the nature of lesions. Altering patient’s position during examination may help detect anomalies in the form of a floating gallbladder, which may promote its torsion. Finally, pathologies whose diagnosis may be facilitated by color-coded blood flow imaging are also presented. The issues discussed in this paper are only a fraction of problems faced by an ultrasound operator in the field of gallbladder diagnostic imaging. However, the proposed ultrasound approaches should help solve some of these problems in everyday practice.

A Resected Gallbladder Carcinoma Coexisting With Adenomyomatosis Involving Varied Degrees of Intraepithelial Dysplasia: A Case Report and Literature Review

A 59-year-old asymptomatic man underwent ultrasonography, which revealed gallstones and thickened gallbladder wall. Abdominal computed tomography (CT) showed a slightly swollen bilocular gallbladder and a soft tissue mass in the fundus site. Segmental adenomyomatosis (ADM) was suspected because numerous fundic cystic lesions were seen on magnetic resonance imaging. Endoscopic ultrasonography revealed numerous Rokitansky-Aschoff sinuses (RAS) and a papillary soft tissue shadow surrounded with irregular and remarkably thickened fundic gallbladder wall. Fluoro-2-deoxy-D-glucose-positron emission tomography/CT demonstrated slightly increased fluoro-2-deoxy-D-glucose uptake in the corresponding lesion. Surgery was performed under a diagnosis of gallbladder carcinoma (GBC) with concomitant ADM, and histopathology revealed a 30-mm papillotubular adenocarcinoma extending from the gallbladder body to fundus with invasion into the subserosa. Numerous RAS were present throughout the gallbladder showing various degrees of dysplasia. Ki67 and p53-labeling index (LI) was significantly higher in the dysplastic epithelium compared with normal fundic epithelium. p53-LI was also markedly increased (72.1%) in tissue in front of tumor invasion. Interestingly, these hyperproliferation indicators were extremely high (Ki67-LI: 28.8%; p53-LI: 91.9%) in RAS with low-grade dysplasia even in the gallbladder neck. Although, generally, tumors do not develop in the gallbladder neck with segmental ADM, our results suggest that a gallbladder with ADM has potential for carcinogenesis regardless of location, with segmental ADM. On the basis of histopathology, our patient was diagnosed with GBC arising from RAS with multicentric and multistep growth. A relationship between GBC and ADM, especially segmental ADM, has been suggested but remains controversial. Our experience is very suggestive of carcinogenesis developing from ADM.

Differentiation of gallbladder adenomyomatosis from early-stage gallbladder cancer before surgery

Backgrounds/Aims

This study aimed to compare the perioperative and clinical outcomes in patients undergoing laparoscopic cholecystectomy for gallbladder adenomyomatosis (GBA) or early-stage gallbladder cancer (GBC).

Methods

The perioperative and clinical outcomes of 194 patients diagnosed with GBA and 30 patients diagnosed with GBC who underwent laparoscopic cholecystectomy in our institution from January 2011 to December 2017 were retrospectively compared.

Results

There were no significant differences between the GBA and GBC groups in sex (male:female ratio 1.0:0.8 vs. 1.0:0.7, p=0.734), BMI (23.9±3.4 vs. 24.0±3.8 kg/m², p=0.916), or preoperative liver function tests. Patients in the GBC group were significantly older (50.5±14.1 vs. 65.9±10.6 years, p<0.001) and had a higher ASA grade (40.3 vs. 63.4% grade II or III, p=0.043) than patients in the GBA group. Although there was no significant difference in preoperative diagnostic methods (p=0.442), the GBC group showed a significantly higher rate of misdiagnosis on preoperative imaging compared with postoperative histopathologic findings (30.9% vs. 53.3%, p=0.011). There were significantly more patients with gallstones in the GBA group than in the GBC group (68.6% vs. 40.0%, p=0.004).

Conclusions

In older patients hospitalized for biliary colic without gallstones but with a thickened gallbladder wall with inflammation on preoperative diagnostic exam, the possibility of early-stage GBC should be considered.

Computer-aided diagnosis of gallbladder polyps based on high resolution ultrasonography

BACKGROUND AND OBJECTIVE

Gallbladder polyp is a common disease with an overall population prevalence between 4 and 7%. It can be classified as neoplastic and non-neoplastic lesions. Surgical treatment is necessary for neoplastic polyps. Due to its easy accessibility and nonradioactive, ultrasonography is the mostly used preoperative diagnosis tool for gallbladder polyps. However, human image analysis depends greatly on levels of experience, which results in many overtreatment cases and undertreatment cases in clinics.

METHODS

In this study, we proposed an ultrasound image segmentation algorithm, combined with principal components analysis (PCA) and AdaBoost algorithms to construct a computer-aided diagnosis system for the differentiate diagnosis of neoplastic and non-neoplastic gallbladder polyps.

RESULTS

The proposed segmentation method achieved a high accuracy of 95% for outlining the gallbladder region. The accuracy, sensitivity, specificity for the proposed computer-aided diagnosis system based on the segmented images are 87.54%, 86.52% and 89.40%, compared to 69.05%, 67.86% and 70.17% with convolutional neural network. The diagnosis result is also slightly higher than the human eyes of sonologists (86.22%, 85.19% and 89.18% as an average of four sonologists), while with a much faster diagnosis speed (0.02s vs 3s).

CONCLUSIONS

We proposed an efficient ultrasound image segmentation approach and a reliable system of automatic diagonals of neoplastic and non-neoplastic gallbladder polyps. The results show that the diagnosis accuracy is competitive to the expert sonologists while requires much less diagnosis time.

Range-ambiguity artifact in abdominal ultrasound

Range-ambiguity artifacts (RAAs) are an erroneous mapping of returning echoes into a composite picture. The purpose of this review was to illustrate the mechanism of RAAs and to present the diagnostic problems caused by RAAs. RAA features differ slightly from organ to organ. At the level of the urinary bladder, RAAs take the form of a cloud-like, ill-demarcated, immobile, echogenic area, and the depth of the echogenic area differs depending on the pulse repetition frequency (PRF). This form is referred to as "static RAA" in this review. There are two key ultrasound characteristics of RAAs at the level of the liver: (a) the depth of RAAs change according to the PRF, and (b) RAAs move in accordance with the cardiac cycle. This form is referred to as "mobile RAA" in this review. At the level of the gallbladder, RAAs take the form of fine echogenic lines in the gallbladder. This phenomenon is actually a combination of two phenomena: a ring-down artifact and RAA. This form is referred to as "complex RAA (searchlight phenomenon)" in this review. The easiest way to reduce RAAs is to change the image depth. Sufficient knowledge of RAAs can prevent misdiagnosis of erroneously displayed returning echoes as real pathologic changes.

Ultrasonic sector imaging using plane wave synthetic focusing with a convex array transducer

Synthetic transmit focusing (STF) methods using unfocused waves or plane waves (PWs) have recently been investigated extensively. However, STF using PWs with a convex array (PWSTF-CA) has not been rigorously studied for high-resolution sector imaging. In this paper, the authors suggest an analytical model for accurate characterization of the spatial beam patterns of PWSTF-CA using a large range of either uniformly or non-uniformly distributed PW angles. On the basis of the model, a frame-based PWSTF-CA approach with non-uniform PW angles is suggested to achieve superior image quality at a higher frame rate than conventional transmit focusing (CTF). The analytical model can also be used for optimal selection of a set of PW angles to scan the entire sectorial field of view and its subsets employed for STF at each imaging point. The authors also investigate how to select transmit subarrays for each of the PWs to obtain the best spatial resolution. A theoretical analysis and simulations are conducted for the verification of the analytical model and the optimal utilization strategy of PWSTF-CA. The results indicate that the PWSTF-CA improves not only the frame rate but also the contrast, signal-to-noise ratio, and resolution compared with the CTF, as in the case of PWSTF with linear arrays.

Pathogenesis of gallbladder adenomyomatosis and its relationship with early-stage gallbladder carcinoma: an overview

The exact pathogenesis of gallbladder adenomyomatosis is still lacking and some controversies over its diagnosis and treatment exist. Originally recognized as a precancerous lesion, adenomyomatosis is currently recognized by recent studies as a benign alteration of the gallbladder that is often associated with cholecystitis and cholecystolithiasis. Gallbladder carcinoma is an extremely malignant disease with a 5-year survival rate of less than 5%. Therefore, it is important to diagnose, differentiate, and confirm the relationship between adenomyomatosis and early-stage gallbladder carcinoma. However, the early clinical symptoms of adenomyomatosis are extremely similar to those of gallbladder stones and cholecystitis, increasing the difficulty to identify and treat this disease. This article summarizes the research progress on gallbladder adenomyomatosis, aiming to improve the understanding of the pathogenesis of adenomyomatosis and further provide insight for its clinical diagnosis and treatment.

CT diagnosis of gallbladder adenomyomatosis: importance of enhancing mucosal epithelium, the "cotton ball sign"

OBJECTIVES

To determine the diagnostic value of the cotton ball sign and other CT features in patients with gallbladder (GB) wall thickenings (WTs).

METHODS

Three blinded readers reviewed the preoperative CT and MR images of 101 patients with pathologically confirmed GB adenomyomatosis (GA) (n = 34) and other benign (n = 29), malignant (n = 41), and premalignant (n = 2) GBWTs. Three readers analysed the morphological features of GBWT and presence of the "cotton ball sign", defined as fuzzy grey dots in GBWT or a dotted outer border of the inner enhancing layer on contrast-enhanced (CE) CT. In addition, the "pearl necklace sign" on MR was analysed.

RESULTS

In the GA group (n = 34), prevalence of the cotton ball sign and pearl necklace sign was 74% (25/34) and 44% (15/34), respectively. Presence of the cotton ball sign, smooth contour of the mucosa, double-layering enhancement, and enhancement degree weaker than the renal cortex on CT images were significant predictors of benign GBWT (p < 0.01). When differentiating GA from GB malignancy or premalignancy, accuracy of the cotton ball sign and pearl necklace sign was 81% (62/77) and 74% (57/77), respectively.

CONCLUSION

The cotton ball sign on CE-CT showed higher sensitivity and comparable specificity to those of the pearl necklace sign in differentiating GA from malignancy.

KEY POINTS

• Prevalence of the cotton ball sign on CT was 74% in gallbladder adenomyomatosis. • The cotton ball sign was useful in differentiating gallbladder adenomyomatosis from gallbladder cancer. • The cotton ball sign was more sensitive than the pearl necklace sign for adenomyomatosis diagnosis.

Gallbladder cancer with tumor thrombus in the portal vein: A case report

RATIONALE

Gallbladder cancer (GBC) is a highly fatal malignancy. Due to its invasiveness and delayed diagnosis, many GBC patients are diagnosed with synchronous liver and hepatoduodenal ligament involvement. In our case, we report a gallbladder cancer with portal vein thrombus.

PATIENT CONCERNS

A 60-year-old woman presented with persistent upper abdominal dull pain for 2 months.

DIAGNOSES

Ultrasound examination showed gallbladder carcinoma invading liver segment IV, and a tumor thrombus in the left and right main portal trunk. Ultrasonography and contrast-enhanced magnetic resonance imaging (MRI) showed gallbladder carcinoma with invasion of adjacent liver, and tumor thrombus in the right branch of the portal vein and intrahepatic bile duct. Abdominal computed tomography angiography (CTA) revealed no hepatic artery invasion.

INTERVENTIONS

We made a decision to perform extended right lobectomy. Twenty-six days later, the patient underwent intravenous infusion port implantation for S-1 plus oxaliplatin (SOX) therapy.

OUTCOMES

After treatment, the patient has been doing very well and no recurrence has been found for 5 months.

LESSONS

The patient with gallbladder cancer and tumor thrombus in the portal vein described in this report provides a reminder for surgeons of the importance of early diagnosis, and adequate surgical and adjuvant treatment. Multi-disciplinary treatment is significantly beneficial for the overall survival of patients with advanced GBC.

Comparison of DWIBS/T2 image fusion and PET/CT for the diagnosis of cancer in the abdominal cavity

Fusion images of diffusion-weighted whole-body imaging with background body signal suppression and T2-weighted image (DWIBS/T2) demonstrate a strong signal for malignancies, with a high contrast against the surrounding tissues, and enable anatomical analysis. In the present study, DWIBS/T2 was compared with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for diagnosing cancer in the abdomen. Patient records, including imaging results of examination conducted between November 2012 and May 2014, were analyzed retrospectively. In total, 10 men (age, 73.6±9.6 years) and 8 women (age, 68.9±7.1 years) were enrolled into the current study. Of the enrolled patients, 2 were diagnosed with hepatocellular carcinoma, 1 with cholangiocellular carcinoma, 1 with liver metastasis, 2 with pancreatic ductal adenocarcinoma, 1 with renal cell carcinoma and 1 with malignant lymphoma. Benign lesions were also analyzed, including adenomyomatosis of the gallbladder (5 patients), intraductal papillary mucinous neoplasm (4 patients) and right adrenal adenoma (1 case). All the patients with cancer showed positive results on DWIBS/T2 images. However, only 7 out of 8 patients were positive with PET/CT. One patient with right renal cellular carcinoma was positive with DWIBS/T2, but negative with PET/CT. All the patients with benign lesions were negative with DWIBS/T2 and PET/CT. In conclusion, DWIBS/T2 was more sensitive in diagnosing cancer of organs in the abdominal cavity compared with PET/CT. Furthermore, negative results with DWIBS/T2 and PET/CT were useful for the diagnosis of benign lesions, such as adenomyomatosis of the gallbladder and intraductal papillary mucinous neoplasm.

Risk stratification of gallbladder polyps larger than 10 mm using high-resolution ultrasonography and texture analysis

OBJECTIVES

To assess important features for risk stratification of gallbladder (GB) polyps >10 mm using high-resolution ultrasonography (HRUS) and texture analysis.

METHODS

We included 136 patients with GB polyps (>10 mm) who underwent both HRUS and cholecystectomy (non-neoplastic, n = 58; adenomatous, n = 32; and carcinoma, n = 46). Two radiologists retrospectively assessed HRUS findings and texture analysis. Multivariate analysis was performed to identify significant predictors for neoplastic polyps and carcinomas.

RESULTS

Single polyp (OR, 3.680-3.856) and larger size (OR, 1.450-1.477) were independently associated with neoplastic polyps (p < 0.05). In a single or polyp >14 mm, sensitivity for differentiating neoplastic from non-neoplastic polyps was 92.3%. To differentiate carcinoma from adenoma, sessile shape (OR, 9.485-41.257), larger size (OR, 1.267-1.303), higher skewness (OR, 6.382) and lower grey-level co-occurrence matrices (GLCM) contrast (OR, 0.963) were significant predictors (p < 0.05). In a polyp >22 mm or sessile, sensitivity for differentiating carcinomas from adenomas was 93.5-95.7%. If a polyp demonstrated at least one HRUS finding and at least one texture feature, the specificity for diagnosing carcinoma was increased to 90.6-93.8%.

CONCLUSION

In a GB polyp >10 mm, single and diameter >14 mm were useful for predicting neoplastic polyps. In neoplastic polyps, sessile shape, diameter >22 mm, higher skewness and lower GLCM contrast were useful for predicting carcinoma.

KEY POINTS

• Risk of neoplastic polyp is low in <14 mm and multiple polyps • A sessile polyp or >22 mm has increased risk for GB carcinomas • Higher skewness and lower GLCM contrast are predictors of GB carcinoma • HRUS is useful for risk stratification of GB polyps >1 cm.

Gallbladder adenomyomatosis: imaging findings, tricks and pitfalls

Abstract

Gallbladder adenomyomatosis (GA) is a benign alteration of the gallbladder wall that can be found in up to 9% of patients. GA is characterized by a gallbladder wall thickening containing small bile-filled cystic spaces (i.e., the Rokitansky–Aschoff sinuses, RAS). The bile contained in RAS may undergo a progressive concentration process leading to crystal precipitation and calcification development. A correct characterization of GA is fundamental in order to avoid unnecessary cholecystectomies. Ultrasound (US) is the imaging modality of choice for diagnosing GA; the use of high-frequency probes and a precise focal depth adjustment enable correct identification and characterization of GA in the majority of cases. Contrast-enhanced ultrasound (CEUS) can be performed if RAS cannot be clearly identified at baseline US: RAS appear avascular at CEUS, independently from their content. Magnetic resonance imaging (MRI) should be reserved for cases that are unclear on US and CEUS. At MRI, RAS can be identified with extremely high sensitivity, but their signal intensity varies widely according to their content. Positron emission tomography (PET) may be helpful for excluding malignancy in selected cases. Computed tomography (CT) and cholangiography are not routinely indicated in the suspicion of GA.

Teaching points

1. Gallbladder adenomyomatosis is a common benign lesion (1–9% of the patients).

2. Identification of Rokitansky–Aschoff sinuses is crucial for diagnosing gallbladder adenomyomatosis.

3. Sonography is the imaging modality of choice for diagnosing gallbladder adenomyomatosis.

4. Intravenous contrast material administration increases ultrasound accuracy in diagnosing gallbladder adenomyomatosis.

5. Magnetic resonance is a problem-solving technique for unclear cases.

Diagnostic accuracy of transabdominal high-resolution US for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with EUS

PURPOSE

To compare the diagnostic accuracy of transabdominal high-resolution ultrasound (HRUS) for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with endoscopic ultrasound (EUS) and pathology.

MATERIALS AND METHODS

Among 125 patients who underwent both HRUS and EUS, we included 29 pathologically proven cancers (T1 = 7, T2 = 19, T3 = 3) including 15 polypoid cancers and 50 surgically proven polyps (neoplastic = 30, non-neoplastic = 20). We reviewed formal reports and assessed the accuracy of HRUS and EUS for diagnosing cancer as well as the differential diagnosis of neoplastic polyps. Statistical analyses were performed using chi-square tests.

RESULTS

The sensitivity, specificity, PPV, and NPV for gallbladder cancer were 82.7 %, 44.4 %, 82.7 %, and 44 % using HRUS and 86.2 %, 22.2 %, 78.1 %, and 33.3 % using EUS. HRUS and EUS correctly diagnosed the stage in 13 and 12 patients. The sensitivity, specificity, PPV, and NPV for neoplastic polyps were 80 %, 80 %, 86 %, and 73 % using HRUS and 73 %, 85 %, 88 %, and 69 % using EUS. Single polyps (8/20 vs. 21/30), larger (1.0 ± 0.28 cm vs. 1.9 ± 0.85 cm) polyps, and older age (52.5 ± 13.2 vs. 66.1 ± 10.3 years) were common in neoplastic polyps (p < 0.05).

CONCLUSION

Transabdominal HRUS showed comparable accuracy for diagnosing gallbladder cancer and differentiating neoplastic polyps compared with EUS. HRUS is also easy to use during our routine ultrasound examinations.

KEY POINTS

• HRUS showed comparable diagnostic accuracy for GB cancer compared with EUS. • HRUS and EUS showed similar diagnostic accuracy for differentiating neoplastic polyps. • Single, larger polyps and older age were common in neoplastic polyps. • HRUS is less invasive compared with EUS.

Xanthogranulomatous cholecystitis: diagnostic performance of US, CT, and MRI for differentiation from gallbladder carcinoma

OBJECTIVES

The purpose of this study is to evaluate the diagnostic performance of HRUS, CT, and MRI for differentiating xanthogranulomatous cholecystitis (XGC) from gallbladder (GB) cancer.

MATERIALS AND METHODS

Patients with surgically proven XGC (n = 40) and GB cancer (n = 44), who had undergone at least one HRUS (n = 43), CT (n = 82), or MRI (n = 34) examination between 2000 and 2012, were included. Two radiologists retrospectively graded the likelihood of XGC or GB cancer using a 5-point confidence scale; they also assessed the imaging features. Statistical analyses were performed using ROC, ANOVA, and Fisher's exact test.

RESULTS

Diagnostic performance of MRI was better than HRUS for differentiating XGC from GB cancer (AUCs = 0.867 and 0.911 vs. AUCs = 0.818 and 0.86). However, HRUS showed a better performance than CT (AUCs = 0.818 and 0.86 vs. AUCs = 0.806 and 0.84) with moderate to excellent agreement (κ = 0.48-0.83). Statistically common findings for XGC included non-focal thickening, smooth GB wall, presence of intramural nodules, type I enhancement of wall, transient hepatic attenuation difference, and continuity of mucosa (p < 0.05). Co-existence of gallstones (OR = 16.5), non-focal thickening (OR = 14.7), and collapsed lumen (OR = 13.0) on HRUS, and type I enhancement on CT (OR = 3.52) were independently associated with XGC (p < 0.05).

CONCLUSION

Although MRI showed a better performance than both HRUS and CT, HRUS showed a better performance than CT. The co-existence of gallstones, non-focal thickening, and collapsed lumen on HRUS was independently associated with XGC.

Negative signals for adenomyomatosis of the gallbladder upon diffusion-weighted whole body imaging with background body signal suppression/T2-weighted image fusion analysis

Differentiation between adenomyomatosis (ADM) and cancer of the gallbladder is necessary during diagnosis. Diffusion-weighted whole body imaging with background body signal suppression (DWIBS) images are able to indicate cancer and inflammation. The fusion of a DWIBS with a T2 weighted image (DWIBS/T2) facilitates both functional and anatomical investigations. In the present study, patient records and images from patients with surgically confirmed ADM from April 2012 to October 2014 were analyzed retrospectively. The enrolled patients, including 6 men (64.2±13.1 years) and 4 women (57.3±12.4 years) were subjected to DWIBS/T2 during routine clinical practice. The diagnosis of ADM was based on magnetic resonance cholangiopancreatography, transabdominal ultrasonography, and endoscopic ultrasonography; ADM was diagnosed definitively when cystic lesions were observed, indicating the Rokitansky-Aschoff sinus. A single patient was indicated to be positive by DWIBS/T2 imaging. The Rokitansky-Aschoff sinus revealed a relatively high signal intensity; however, it was not as strong as that of the spleen. The signal intensity was also high on an apparent diffusion coefficient map, suggesting T2 shine-through. The thickened wall displayed low signal intensity. The aforementioned results indicate that ADM may be negative upon DWIBS/T2 imaging; one false positive case was determined to be ADM, accompanied by chronic cholecystitis. The majority of patients with ADM displayed negative findings upon DWIBS/T2 imaging, and chronic cholecystitis may cause false positives.

A literature review of radiological findings to guide the diagnosis of gallbladder adenomyomatosis

BACKGROUND

Gallbladder adenomyomatosis (GA) is a benign gallbladder entity discovered as an asymptomatic gallbladder mass. Since gallbladder cancer is in the differential diagnosis for gallbladder masses, the ability to differentiate benign disease avoids a more extensive oncologic resection. This study sought to review imaging modalities used to diagnose GA.

METHODS

PubMed and SciVerse Scopus were systematically searched using the terms: "gallbladder adenomyomatosis" and "gallbladder imaging" for articles published between January 2000 and January 2015.

RESULTS

A total of 14 articles were reviewed in this analysis. Contemporary series report the use of ultrasound (US), computed tomography (CT) or magnetic resonance imaging (MRI) in GA imaging. Ultrasound detection of Rokitansky-Aschoff sinuses, visualized as small cystic spaces with associated "comet-tail" or "twinkling" artifact, is pathognomonic for GA. A "Pearl-Necklace" sign of small connected sinuses on MRI or "Rosary" sign on CT are additional characteristics that may assist in establishing a diagnosis.

CONCLUSION

Ultrasound is the most commonly used tool to investigate GA. If not diagnostic, CT or MRI are effective in attempting to differentiate a benign or malignant cholecystic mass. Characteristic signs should lead the surgeon to perform a laparoscopic cholecystectomy in symptomatic patients or manage non-operatively in asymptomatic patients.

Gallbladder carcinoma: causes of misdiagnosis at CT

Gallbladder carcinomas can present with varied imaging features on computed tomography. The three major imaging features include (1) focal or diffuse wall thickening with or without irregularity of the gallbladder; (2) polypoidal intraluminal mass; and (3) large mass obscuring and replacing the gallbladder, often extending to the liver. Patterns of wall thickening or polypoid growth are often confused with various benign gallbladder diseases due to overlap of imaging findings. Moreover, gallbladder carcinomas that coexist with benign gallbladder diseases make accurate preoperative diagnosis more difficult. Recently, high-resolution ultrasound (HRUS) has been regarded as a problem-solving tool for gallbladder diseases. In this article, we will illustrate various imaging presentations of gallbladder cancer, along with imaging pitfalls and recently updated HRUS findings.

Contrast-enhanced ultrasonography diagnosis of fundal localized type of gallbladder adenomyomatosis

Background

Adenomyomatosis of gallbladder is an acquired hyperplastic lesion, characterized by focal or diffuse thickening of the gallbladder with intramural cysts or echogenic areas with comet tail on ultrasonography. But in some cases, especially in the localized fundal type of adenomyomatosis, the intramural anechoic cystic spaces are uncertainty which causes difficult to differential adenomyomatosis from GB cancer. The purpose of this study was to determine the accuracy of real-time contrast-enhanced ultrasonography(CEUS) in the diagnosis of the fundal localized type of gallbladder adenomyomatosis.

Methods

We performed a retrospective study of 21 patients with pathologically proven fundal localized type of gallbladder (GB) adenomyomatosis. All patients underwent preoperative grayscale ultrasound (US) and real-time CEUS examination. The study’s reviewers made the diagnosis of adenomyomatosis according to the presence of the focal thickening of the fundal gallbladder wall with intramural cyst or intramural echogenic foci on grayscale US or CEUS. The diagnostic accuracy of US and CEUS was compared. The enhanced pattern and degree of intactness of the GB wall were also recorded.

Results

The fundal portion of the GB wall showed localized thickness in all 21 patients. Small anechoic spaces or intramural echogenic foci were detected in 14 (66.7 %) and 21 (100 %) of cases respectively, and the intactness of the GB wall’s outer hyper-echoic layer was demonstrated in 17 (81 %) and 20 (95 %) on grayscale US and CEUS, respectively. The accuracy rate of the above two examination modalities was significantly different (p < 0.05). In the arterial phase of the CEUS, areas of focal thickened GB wall were iso-enhanced in 18 cases and hyper-enhanced in 3 cases. All 21 cases appeared to show heterogeneous enhancement with small non-enhancement spaces. The mucosal and serosal layers of the GB wall surrounding the lesions were enhanced, which presented as two “hyper-echoic lines” in the arterial phase of CEUS. In the venous phase of the CEUS, 19 lesions were iso-enhanced and 2 lesions were hypo-enhanced. The small non-enhancement spaces were more clearly during the venous phase.

Conclusion

The small non-enhancement space is a characteristic finding of the fundal localized type of gallbladder adenomyomatosis on CEUS. CEUS could increase the degree of visualization of Rokitansky-Aschoff sinuses (RAS) and intactness of the GB wall, which play an important role in differential diagnosis.

High-resolution sonography for distinguishing neoplastic gallbladder polyps and staging gallbladder cancer

OBJECTIVE. The purposes of this study were to compare staging accuracy of high-resolution sonography (HRUS) with combined low- and high-MHz transducers with that of conventional sonography for gallbladder cancer and to investigate the differences in the imaging findings of neoplastic and nonneoplastic gallbladder polyps. MATERIALS AND METHODS. Our study included 37 surgically proven gallbladder cancer (T1a = 7, T1b = 2, T2 = 22, T3 = 6), including 15 malignant neoplastic polyps and 73 surgically proven polyps (neoplastic = 31, nonneoplastic = 42) that underwent HRUS and conventional transabdominal sonography. Two radiologists assessed T-category and predefined polyp findings on HRUS and conventional transabdominal sonography. Statistical analyses were performed using chi-square and McNemar tests. RESULTS. The diagnostic accuracy for the T category was T1a = 92-95%, T1b = 89-95%, T2 = 78-86%, and T3 = 84-89%, all with good agreement (κ = 0.642) using HRUS. The diagnostic accuracy for differentiating T1 from T2 or greater than T2 was 92% and 89% on HRUS and 65% and 70% with conventional transabdominal sonography. Statistically common findings for neoplastic polyps included size greater than 1 cm, single lobular surface, vascular core, hypoechoic polyp, and hypoechoic foci (p < 0.05). The value of HRUS in the differential diagnosis of a gallbladder polyp was more clearly depicted internal echo foci than conventional transabdominal sonography (39 vs 21). A polyp size greater than 1 cm was independently associated with a neoplastic polyp (odds ratio = 7.5, p = 0.02). The AUC of a polyp size greater than 1 cm was 0.877. The sensitivity and specificity were 66.67% and 89.13%, respectively. CONCLUSION. HRUS is a simple method that enables accurate T categorization of gallbladder carcinoma. It provides high-resolution images of gallbladder polyps and may have a role in stratifying the risk for malignancy.

Surgical treatment of gallbladder cancer: Strategy and optimization

Gallbladder cancer is the most common malignant tumor of the biliary tract. It is difficult to diagnose early due to the lack of special symptoms and physical signs. Most cases are diagnosed in advanced stages and the response to traditional chemotherapy and radiotherapy is extremely limited, with modest impact on overall survival. Despite improvements in outcome associated with extended resections, selection of patients for such extensive surgery remains controversial. In this article, we analyze and discuss the key issues about the surgical management of gallbladder cancer, with the hope of a more comprehensive recognition of this malignancy.

Differential diagnosis of gallbladder wall thickening: the usefulness of contrast-enhanced ultrasound

he purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of gallbladder wall (GBW) thickening and determine the predictors of malignant GBW thickening. One hundred fifty-nine patients with GBW thickening, including 76 men and 83 women, from eight institutions were enrolled. CEUS was performed after injection of a sulfur hexafluoride microbubble-based ultrasound contrast agent. Multiple logistic regression analysis was used to reveal independent predictor sassociated with malignant GBW thickening. The final diagnoses were 48 gallbladder carcinomas and 111 benign gallbladder diseases.Maximal thicknesses of the GBW in malignant and benign GB Wthickening were 17.3 ± 5.2 (6 – 30) mm and 8.6 ± 5.1 (4 – 26) mm respectively (p , 0.001). CEUS revealed significant differences in intralesional vessels, enhancement homogeneity, time to hypo-enhancement, inner layer discontinuity, outer layer discontinuity and adjacent liver involvement (all p-values , 0.05) between malignant and benign GBW thickening. Patient age . 46.5 y, focal GBW thickening, inner layer discontinuity and outer layer discontinuity were found to be associated with malignancy by multiple logistic regression analysis (all p-values , 0.05). Receiver operating characteristic curve analysis revealed Az values for patient age, focal GBW thickening, inner wall discontinuity and outer wall discontinuity of 0.709 (95%confidence interval [CI]: 0.627–0.790), 0.714 (95% CI: 0.630–0.798), 0.860 (95%CI: 0.791 – 0.928) and 0.858 (95% CI: 0.783 – 0.933), respectively. CEUS is useful in the differential diagnosis between malignant and benign GBW thickening. Focal GBW thickening, inner wall discontinuity and outer wall discontinuity observed on CEUS are diagnostic clues for malignant GBW thickening.

Gallbladder cancer

Gallbladder cancer is the fifth most common cancer involving gastrointestinal tract, but it is the most common malignancy of the biliary tract, accounting for 80-95% of biliary tract cancers. This tumor is a highly lethal disease with an overall 5-year survival of less than 5% and mean survival mere than 6 months. An early diagnosis is essential as this malignancy progresses silently with a late diagnosis. The percentage of patients diagnosed to have gallbladder cancer after simple cholecystectomy for presumed gallbladder stone disease is 0.5-1.5%. Patients with preoperative suspicion of gallbladder cancer should not be treated by laparoscopy. Epidemiological studies have identified striking geographic and ethnic disparities-inordinately high occurrence in American Indians, elevated in Southeast Asia, yet quite low elsewhere in the Americas and the world. Environmental triggers play a critical role in eliciting cancer developing in the gallbladder, best exemplified by cholelithiasis and chronic inflammation from biliary tract and parasitic infections. Improved imaging modalities and improved radical aggressive surgical approach in the last decade has improved outcomes and helped prolong survival in patients with gallbladder cancer. The overall 5-year survival for patients with gallbladder cancer who underwent R0 curative resection was from 21% to 69%. In the future, the development of potential diagnostic markers for disease will yield screening opportunities for those at risk either with ethnic susceptibility or known anatomic anomalies of the biliary tract.