CT differentiation of adenomyomatosis and gallbladder cancer

Should we suspect gallbladder cancer if which CT finding is observed in patients with localized gallbladder wall thickening?

PURPOSE

To identify high-risk computed tomography (CT) features for predicting gallbladder (GB) cancer in patients presenting with localized GB wall thickening.

METHODS

This retrospective analysis included 120 patients (mean age: 63.9 ± 10.0 years; 51 men) exhibiting localized GB wall thickening on CT scans obtained between January 2008 and May 2017. Two radiologists independently evaluated CT imaging features for predicting GB cancer. The diagnostic performance of significant imaging features and their combinations was evaluated. High-risk CT features ranked by accuracy were delineated for predicting GB cancer.

RESULTS

This study included 55 patients with GB cancer and 65 with benign GB conditions. The top-four most accurate CT imaging features for predicting GB cancer were identified: heterogeneously enhancing single layer or strongly enhancing thick inner layer; GB wall thickness > 6.5 mm; hyperenhancement on arterial phase; and absence of intramural small cystic lesions (accuracies of 90.0 %, 88.3 %, 85.0 %, and 85.0 %, respectively). The combination of any three high-risk features exhibited the highest accuracy (94.2 %). The presence of any high-risk feature yielded a sensitivity of 100 %, whereas that of all high-risk features indicated a specificity of 100 %.

CONCLUSION

CT imaging features, whether alone or in combination, could effectively and accurately predict GB cancer among patients with localized GB wall thickening. This finding holds significance in guiding decisions regarding further diagnostic tests and treatment planning.

Symptomatic Gallbladder Adenomyomatosis: A rare clinical presentation

INTRODUCTION AND IMPORTANCE

Gallbladder Adenomyomatosis (GA) is a benign rare condition that is mostly asymptomatic but can present as abdominal pain. GA usually occurs in the middle-aged population with an equal sex distribution.

CASE PRESENTATION

A case of a 49-years-old female who sought medical care several times due to abrupt abdominal pain. She underwent echography, Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI) before performing laparoscopic cholecystectomy for symptomatic GA. The pathology report confirmed acalculous cholecystitis in the presence of GA.

CLINICAL DISCUSSION

In fact, echography can reveal the "comet- tail" sign, the CT can show the "rosary sign"; and MRI shows the "pearl necklace" sign. These signs, in the absence of gallstones, can justify the abdominal pain hence the diagnosis of symptomatic GA.

CONCLUSION

GA is being increasingly reported; however, symptomatic cases remain the exception. We believe that awareness to this entity should be raised so that healthcare professionals can establish the diagnosis efficiently.

Imaging update on gallbladder adenomyomatosis and its mimics

Radiologists across many imaging modalities commonly encounter gallbladder adenomyomatosis. The classic imaging appearances of gallbladder adenomyomatosis are well described and confirm benignity. However, in clinical practice, adenomyomatosis can be challenging to differentiate from other gallbladder pathologies that require cholecystectomy. In this article, we describe the common and uncommon appearances of gallbladder adenomyomatosis on multimodality imaging, helping differentiate adenomyomatosis from non-benign gallbladder abnormalities. Accurately differentiating adenomyomatosis from its mimics provides the surgical team with important clinical and surgical management information, improving patient outcomes.

Optimal radiological gallbladder lesion characterization by combining visual assessment with CT-based radiomics

OBJECTIVES

Differentiating benign gallbladder diseases from gallbladder cancer (GBC) remains a radiological challenge because they can appear very similar on imaging. This study aimed at investigating whether CT-based radiomic features of suspicious gallbladder lesions analyzed by machine learning algorithms could adequately discriminate benign gallbladder disease from GBC. In addition, the added value of machine learning models to radiological visual CT-scan interpretation was assessed.

METHODS

Patients were retrospectively selected based on confirmed histopathological diagnosis and available contrast-enhanced portal venous phase CT-scan. The radiomic features were extracted from the entire gallbladder, then further analyzed by machine learning classifiers based on Lasso regression, Ridge regression, and XG Boosting. The results of the best-performing classifier were combined with radiological visual CT diagnosis and then compared with radiological visual CT assessment alone.

RESULTS

In total, 127 patients were included: 83 patients with benign gallbladder lesions and 44 patients with GBC. Among all machine learning classifiers, XG boosting achieved the best AUC of 0.81 (95% CI 0.72-0.91) and the highest accuracy rate of 73% (95% CI 65-80%). When combining radiological visual interpretation and predictions of the XG boosting classifier, the highest diagnostic performance was achieved with an AUC of 0.98 (95% CI 0.96-1.00), a sensitivity of 91% (95% CI 86-100%), a specificity of 93% (95% CI 90-100%), and an accuracy of 92% (95% CI 90-100%).

CONCLUSIONS

Machine learning analysis of CT-based radiomic features shows promising results in discriminating benign from malignant gallbladder disease. Combining CT-based radiomic analysis and radiological visual interpretation provided the most optimal strategy for GBC and benign gallbladder disease differentiation.

KEY POINTS

Radiomic-based machine learning algorithms are able to differentiate benign gallbladder disease from gallbladder cancer. Combining machine learning algorithms with a radiological visual interpretation of gallbladder lesions at CT increases the specificity, compared to visual interpretation alone, from 73 to 93% and the accuracy from 85 to 92%. Combined use of machine learning algorithms and radiological visual assessment seems the most optimal strategy for GBC and benign gallbladder disease differentiation.

[Incidental and "leave me alone" findings of abdominal organs-part 1 : Liver, gall ducts and pancreas]

Incidentalomas of the parenchymal organs of the abdomen, i.e. radiological findings in these organs that are not the primary focus of the clinical question, are frequent in this region of the body. In particular, findings presumed to be unimportant, such as cystic masses in the liver, the bile duct system or the pancreas, initially appear to be irrelevant in the diagnosis. For the liver we define the mostly clearly diagnosable simple cysts and hemangiomas as leave me alone lesions. Otherwise, we recommend a classification of incidentalomas into the three major categories (<0.5 cm, 0.5-1.5 cm and >1.5 cm) as well as an assessment with respect to clearly benign and suspect imaging characteristics in the context of a classification of patients into three different risk groups.

The Effectiveness of Identifying Primary Gallbladder Adenocarcinoma Utilizing Contrast-Enhanced Ultrasound: A Case Report

Gallbladder carcinoma is rare and difficult to detect in the early stages of the disease process, due to lack of symptoms. Sonography is typically the first modality of choice for assessing gallbladder pathology due to its high sensitivity, portability, real-time imaging capability, and non-ionizing technique. Conventional gray-scale and color Doppler sonographic imaging may be ambiguous for diagnosing solid tumors, such as gallbladder carcinoma. In this case, gallbladder carcinoma was definitively diagnosed utilizing contrast-enhanced ultrasound, allowing for quick patient treatment options and an optimal surgical outcome.

Diagnostic performance of preoperative CT in differentiating between benign and malignant origin of suspicious gallbladder lesions

PURPOSE

To determine diagnostic performance of preoperative CT in differentiating between benign and malignant suspicious gallbladder lesions and to develop a preoperative risk score.

METHOD

All patients referred between January 2007 and September 2018 for suspicion of gallbladder cancer (GBC) or incidentally found GBC were retrospectively analyzed. Patients were excluded when preoperative CT or histopathologic examination was lacking. Two radiologists, blinded to histopathology results, independently reviewed CT images to differentiate benign disease from GBC. Multivariable analysis and internal validation were used to develop a risk score for GBC. Model discrimination, calibration, and diagnostic performance were assessed.

RESULTS

In total, 118 patients with 39 malignant (33 %) and 79 benign (67 %) lesions were included. Sensitivity of CT for diagnosing GBC was 90 % (95 % confidence interval [CI]: 76-97). Specificity rates were 61 % (95 % CI: 49-72) and 59 % (95 % CI: 48-70). Three predictors of GBC (irregular lesion aspect, absence of fat stranding, and locoregional lymphadenopathy) were included in the risk score ranging from -1 to 4. Adequate performance was found (AUC: 0.79, calibration slope: 0.89). In patients allocated >0 points, the model showed higher performance in excluding GBC than the radiologists (sensitivity 92 % [95 % CI: 79-98]). Moreover, when allocated >3 points, the risk score was superior in diagnosing GBC (specificity 99 % [95 % CI: 93-100]).

CONCLUSIONS

Sensitivity rates of CT for differentiation between benign and malignant gallbladder lesions are high, however specificity rates are relatively low. The proposed risk score may facilitate differentiation between benign and malignant suspicious gallbladder lesions.

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.

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.

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.

Chronic inflammation-related radiological findings of gallbladder adenomyomatosis

PURPOSE

This study aimed to assess radiological findings of adenomyomatosis advancing to chronic inflammation to differentiate between adenomyomatosis with and without chronic inflammation.

MATERIALS AND METHODS

We retrospectively identified 79 patients with pathologically proven adenomyomatosis without (n = 10) or with chronic inflammation (n = 69), who underwent computed tomography (CT) and magnetic resonance imaging (MRI) followed by surgery. MRI analysis included evaluation of GB wall-thickening type, presence and location of intramural cysts, and presence of stones. CT analysis included GB wall-thickening type only. Multivariate logistic regression analysis was used to identify the image-based findings of adenomyomatosis associated with chronic inflammation.

RESULTS

On univariate analysis, MRI-based GB wall-thickening type and presence of stones, and CT-based GB wall-thickening type were significantly different between adenomyomatosis with and without chronic inflammation. On multivariate analysis, only the absence of stones was identified as a significant predictor of adenomyomatosis without chronic inflammation (odds ratio 5.58; 95% confidence interval 1.20-26.01; p = 0.029). There was no significant difference in other MRI- and CT-based findings between adenomyomatosis with and without chronic inflammation.

CONCLUSION

In patients with adenomyomatosis, the presence of stones was independently associated with chronic inflammation.

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.

Uncommon Intraluminal Tumors of the Gallbladder and Biliary Tract: Spectrum of Imaging Appearances

Intraluminal pathologic conditions of the bile ducts and gallbladder are common, most frequently consisting of calculi and adenocarcinoma. In recent years, intraductal papillary neoplasm of the bile ducts (IPN-B), which is analogous to intraductal papillary mucinous neoplasm of the pancreas, has been recognized as a distinct pathologic entity and a precursor lesion to adenocarcinoma of the bile ducts. Intraductal tubulopapillary neoplasm (ITPN) of the bile duct was subsequently described as a distinct pathologic entity. With increased awareness and advances in imaging techniques, these lesions are diagnosed with increased frequency at preoperative imaging. A similar neoplasm in the gallbladder is referred to as intracholecystic papillary neoplasm. These lesions are often diagnosed at a preinvasive stage and have a better prognosis than invasive cholangiocarcinoma when treated with curative resection, underscoring the importance of an accurate imaging diagnosis. The most common causes of polypoid lesions of the gallbladder are cholesterol polyps and adenomyomatosis. These lesions need to be differentiated from the less common but clinically important adenocarcinoma of the gallbladder. Imaging is crucial to identify polyps that are at high risk for malignancy so that the appropriate management choice between imaging follow-up and cholecystectomy can be made by the treating physicians. Other less common gallbladder tumors, such as gallbladder adenomas, lymphoma, and metastases to the gallbladder, can manifest as intraluminal tumors; and awareness of these lesions is also important. In this article, the recent literature is reviewed; and the imaging appearances, histopathologic findings, and management of uncommon intraluminal tumors of the bile ducts and gallbladder and their mimics are discussed. ^©RSNA, 2019.

Incidentally Detected Focal Fundal Gallbladder Wall Thickening at Contrast-Enhanced Computed Tomography: Prevalence and Computed Tomography Features of Malignancy

OBJECTIVE

The aim of this study was to determine the prevalence and computed tomography (CT) features of malignancy in incidental focal fundal gallbladder wall thickening.

METHODS

Patients with incidental focal fundal gallbladder wall thickening on CT were included if they had an ultrasound or magnetic resonance imaging diagnostic of the etiology (n = 19), stability on CT for 1 year (n = 84), or pathological correlation (n = 13). Morphologies were classified as type 1 (nodular/pinched intramural low attenuation), type 2 (intramural low attenuation), type 3 (homogeneous enhancement), type 4 (nodular/pinched homogeneous enhancement), type 5 (intramural cystic spaces), or type 6 (hyperenhancing/heterogeneous enhancement).

RESULTS

One hundred sixteen patients had the following morphologies: type 1 (n = 57), type 2 (n = 10), type 3 (n = 6), type 4 (n = 19), type 5 (n = 14), and type 6 (n = 10). Four cases (3.4%; 95% confidence interval, 0.9%-8.6%) of malignancy were identified (type 6 in 3 and type 3 in 1).

CONCLUSIONS

Incidental focal fundal gallbladder wall thickening is usually benign. Computed tomography features help distinguish benign from malignant etiologies.

Comet tail artifact on ultrasonography: is it a reliable finding of benign gallbladder diseases?

Purpose

The aim of this study was to evaluate whether the comet tail artifact on ultrasonography can be used to reliably diagnose benign gallbladder diseases.

Methods

This retrospective study reviewed the clinical findings, imaging findings, preoperative ultrasonographic diagnoses, and pathological diagnoses of 150 patients with comet tail artifacts who underwent laparoscopic cholecystectomy with pathologic confirmation. The extent of the involved lesion was classified as localized or diffuse, depending on the degree of involvement and the anatomical section of the gallbladder that was involved. This study evaluated the differences in clinical and imaging findings among pathologic diagnoses.

Results

All gallbladder lesions exhibiting the comet tail artifact on ultrasound examination were confirmed as benign gallbladder diseases after cholecystectomy, including 71 cases of adenomyomatosis (47.3%), 74 cases of chronic cholecystitis (49.3%), two cases of xanthogranulomatous cholecystitis (1.3%), and three cases of cholesterolosis (2.0%); there were two cases of coexistent chronic cholecystitis and low-grade dysplasia. There were no statistically significant differences in any of the clinical and ultrasonographic findings, with the exception of gallstones (P=0.007), among the four diseases. There were no significant differences in the average length, thickness, or number of comet tail artifacts among the four diagnoses. No malignancies were detected in any of the 150 thickened gallbladder lesions.

Conclusion

The ultrasonographic finding of the comet tail artifact in patients with thickened gallbladder lesions is associated with the presence of benign gallbladder diseases, and can be considered a reliable sign of benign gallbladder disease.

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.

Imaging Evaluation of Enhancement Patterns of Flat Gall Bladder Wall Thickening and Its Correlation with Clinical and Histopathological Findings

INTRODUCTION

Gall bladder Wall Thickening (GWT) is caused by wide spectrum of diseases. Initially Ultrasound (USG) was used as imaging modality for screening of acute abdomen because of its high sensitivity and real time character. Now, Computed Tomography (CT) is used because of its high temporal and spatial resolution.

AIM

Evaluation of GWT and its enhancement patterns on contrast enhanced CT scan in a bid to differentiate benign from malignant causes and to correlate the imaging features with clinical and histopathological findings.

MATERIALS AND METHODS

It was a hospital based prospective study in which USG was done as an initial modality for screening and Multi Detector Computed Tomography (MDCT) scan was done later on for detailed evaluation of enhancement patterns of GWT. The study cases were then divided into five CT patterns according to enhancement patterns. The diagnostic performance of MDCT was compared with histopathological and serological findings. Relevant history, clinical examination and routine investigations were done.

RESULTS

The one layered pattern with a heterogeneously enhancing thick layered pattern (Type 1) was significantly associated with gall bladder cancer (p<0.001). The sensitivity and specificity of Type 1 enhancement pattern on CT for predicting the Gall Bladder (GB) malignancy were 90.476% and 97.43% respectively. The positive and negative predictive values were 95% and 95%, respectively. Focal wall thickening, irregular margin character and hepatic infiltration by GWT and lymphadenopathy were other findings that predict malignancy (p-value<0.05).

CONCLUSION

MDCT enhancement patterns of a thickened GB wall and associated findings were helpful in differentiating malignant GWT from benign GWT.

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.

Preoperative predictive factors for gallbladder cholesterol polyp diagnosed after laparoscopic cholecystectomy for polypoid lesions of gallbladder

BACKGROUNDS/AIMS

We investigated patients' clinical and radiological data to determine preoperative factors that predict cholesterol gallbladder (GB) polyps of large size, which can be helpful for decision on further diagnostic tools.

METHODS

In this study, we retrospectively analyzed 126 patients who underwent laparoscopic cholecystectomy for GB polyps >10 mm diagnosed preoperatively by abdominal ultrasonography between February 2002 and February 2016 in Department of Surgery, Sanggye Paik Hospital. Patients were divided into non-cholesterol polyps group and cholesterol polyps group, based on the postoperative pathologic diagnosis. Clinical and radiological data, such as gender, age, body weight, height, body mass index (BMI), laboratory findings, size, number and shape of the polypoid lesions, and presence of the concurrent GB stone were compared between the two groups.

RESULTS

Of the 126 cases, 73 had cholesterol polyps (57.9%) and 53 cases were non-cholesterol polyps (42.1%). The younger age (<48.5 years), size of polyp <13.25 mm and multiple polyps were independent predictive variables for cholesterol polyps, with odd ratios (OR) of 2.352 (p=0.045), 5.429 (p<0.001) and 0.472 (p<0.001), respectively.

CONCLUSIONS

Age, size and polyp number were used to predict cholesterol GB polyp among polypoid lesions of the gallbladder >10 mm. For cases in which these factors are not applicable, it is strongly recommended to evaluate further diagnostic tools, such as computed tomography, endoscopic ultrasonography and tumor markers.

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.

Polypoid lesions of the gallbladder: disease spectrum with pathologic correlation

Gallbladder polyps are seen on as many as 7% of gallbladder ultrasonographic images. The differential diagnosis for a polypoid gallbladder mass is wide and includes pseudotumors, as well as benign and malignant tumors. Tumefactive sludge may be mistaken for a gallbladder polyp. Pseudotumors include cholesterol polyps, adenomyomatosis, and inflammatory polyps, and they occur in that order of frequency. The most common benign and malignant tumors are adenomas and primary adenocarcinoma, respectively. Polyp size, shape, and other ancillary imaging findings, such as a wide base, wall thickening, and coexistent gallstones, are pertinent items to report when gallbladder polyps are discovered. These findings, as well as patient age and risk factors for gallbladder cancer, guide clinical decision making. Symptomatic polyps without other cause for symptoms, an age over 50 years, and the presence of gallstones are generally considered indications for cholecystectomy. Incidentally noted pedunculated polyps smaller than 5 mm generally do not require follow-up. Polyps that are 6-10 mm require follow-up, although neither the frequency nor the length of follow-up has been established. Polyps that are larger than 10 mm are typically excised, although lower size thresholds for cholecystectomy may be considered for patients with increased risk for gallbladder carcinoma, such as patients with primary sclerosing cholangitis.

Gallbladder splenosis: a hereto unreported mimicker of a gallbladder neoplasm

Splenosis is a completely benign entity that can mimic a primary mass or metastasis. Herein we report the first known case of gallbladder splenosis in a 49-year-old woman with an extensive surgical and medical history. Cross-sectional computed tomography and MRI demonstrated a single mass arising from the gallbladder fundus. Revelation of splenectomy, confirmed to be traumatic from medical records, raised the suspicion for splenosis. The diagnosis was confirmed with a Technecium-99m-labeled heat-damaged blood cell scan, considered the gold-standard for detection of ectopic splenic tissue.

Features suggestive of gallbladder malignancy: analysis of T1, T2, and T3 tumors on cross-sectional imaging

OBJECTIVES

Gallbladder cancer carries an extremely high mortality rate, with a 5-year survival rate as low as 12%. Survival is dependent on the diagnosis of these tumors in their earliest stages. This study sought to describe the clinical and imaging features of stages T1, T2, and T3 gallbladder tumors and to illustrate features that may allow radiologists to make an early diagnosis.

MATERIALS AND METHODS

After approval from the institutional review board, a search of the pathology department database yielded 18 patients with surgically proven T1, T2, and T3 gallbladder cancers with available preoperative computed tomography (CT) or magnetic resonance imaging. The imaging was reviewed for lesional morphology (focal polyploid mass, focal wall thickening, circumferential wall thickening), enhancement characteristics, liver invasion, locoregional lymphadenopathy, and distant metastatic disease. The electronic medical record was also searched for demographic information and clinical presentation.

RESULTS

There were 10 women and 8 men with a mean age of 69 years. Virtually all patients were symptomatic, with most patients demonstrating symptoms suggestive of underlying malignancy (including jaundice, weight loss, and chronic abdominal pain). Tumors on CT and MRI included 6 polyploid masses, 9 tumors with focal wall thickening, and 3 with circumferential wall thickening. The mean attenuation of those tumors imaged with CT was 59.4 Hounsfield units (HUs) on the arterial phase and 86.5 HUs on the venous phase, with a mean increase in Hounsfield attenuation between the arterial and venous phases of 28.2 HUs. Twelve of the 18 patients were correctly diagnosed prospectively on CT.

CONCLUSIONS

The imaging findings of gallbladder cancer can be subtle, regardless of whether the tumor presents as a discrete mass, focal wall thickening, or circumferential diffuse wall thickening, and radiologists should be aware of the wide range of different possible appearances. Moreover, the vast majority of these patients had clinical symptoms suggestive of an underlying malignancy, and this should precipitate a careful evaluation of the gallbladder in all such cases.

Differentiating between adenomyomatosis and gallbladder cancer: revisiting a comparative study of high-resolution ultrasound, multidetector CT, and MR imaging

Objective

To compare the diagnostic performance of high-resolution ultrasound (HRUS) with contrast-enhanced CT and contrast-enhanced magnetic resonance imaging (MRI) with MR cholangiopancreatography (MRCP) to differentiate between adenomyomatosis (ADM) and gallbladder cancer (GBCA).

Materials and Methods

Forty patients with surgically proven ADM (n = 13) or GBCA at stage T2 or lower (n = 27) who previously underwent preoperative HRUS, contrast-enhanced CT, and contrast-enhanced MRI with MRCP were retrospectively included in this study. According to the well-known diagnostic criteria, two reviewers independently analyzed the images from each modality separately with a five-point confidence scale. The interobserver agreement was calculated using weighted κ statistics. A receiver operating characteristic curve analysis was performed and the sensitivity, specificity, and accuracy were calculated for each modality when scores of 1 or 2 indicated ADM.

Results

The interobserver agreement between the two reviewers was good to excellent. The mean Az values for HRUS, multidetector CT (MDCT), and MRI were 0.959, 0.898, and 0.935, respectively, without any statistically significant differences between any of the modalities (p > 0.05). The mean sensitivity of MRI with MRCP (80.8%) was significantly higher than that of MDCT (50.0%) (p = 0.0215). However, the mean sensitivity of MRI with MRCP (80.8%) was not significantly different from that of HRUS (73.1%) (p > 0.05). The mean specificities and accuracies among the three modalities were not significantly different (p > 0.05).

Conclusion

High-resolution ultrasound and MRI with MRCP have comparable sensitivity and accuracy and MDCT has the lowest sensitivity and accuracy for the differentiation of ADM and GBCA.

Neonatal adenomyomatosis of the gallbladder: An incidental finding at 12 hours of life

Adenomyomatosis of the gallbladder, although relatively common in adults, is a rare entity in the pediatric age group. Controversy still exists as to whether or not to perform followup ultrasound, as there is a questionable increased risk of gallbladder carcinoma in adults. We present a case of neonatal adenomyomatosis that was diagnosed at 12 hours of life in a term newborn.

Focal thickening at the fundus of the gallbladder: computed tomography differentiation of fundal type adenomyomatosis and localized chronic cholecystitis

Background/Aims

The objective of our study was to identify useful computed tomography (CT) findings for differentiating fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder.

Methods

We retrospectively identified cases of 41 patients with pathologically proven adenomyomatosis (n=21) or chronic cholecystitis (n=20) who had fundal thickening of the gallbladder on preoperative abdominal CT. Analysis of the CT findings included evaluation of the thickness, contour, border, intralesional cystic area, adjacent gallbladder wall thickening, presence of inner layer enhancement, enhancement grade, enhancement pattern, and presence of stones. Statistical analyses were performed using the Mann-Whitney U test and Fisher exact test.

Results

Oval contour, inner layer enhancement and intralesional cystic area were more frequently noted in adenomyomatosis than in chronic cholecystitis (p<0.05 for each finding). Flat contour and adjacent gallbladder wall thickening were more frequently observed in chronic cholecystitis than in adenomyomatosis. No differences between adenomyomatosis and chronic cholecystitis in terms of the thickness, enhancement grade, enhancement pattern and presence of stones were apparent.

Conclusions

CT may help to differentiate fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder.

Actual status of clinical diagnosis in patients with primary gallbladder cancer associated with adenomyomatosis

AIM

The purpose of this study was to reveal differences in clinical diagnosis of gallbladder cancer among patients with or without adenomyomatosis (ADM) by analyzing demonstrated tumor patterns on imaging and diagnostic opportunities.

METHODS

Ninety-seven patients with gallbladder cancer were enrolled. Demonstrated imaging patterns were classified into mass lesion (ML), wall thickening (WT), and papillary lesion (PL). Clinical status during periodic follow up and other diagnostic opportunities were determined from medical records.

RESULTS

All adenomyomatosis-associated cases were diagnosed at the T2 or higher stage. The distribution of demonstrated imaging patterns was significantly different between the adenomyomatosis-associated and non-adenomyomatosis-associated groups (p = 0.0002). No adenomyomatosis-associated gallbladder cancer had the PL pattern, which was readily identifiable and characteristic of early-stage cancer. The WT pattern presented difficulties for diagnosis, and the ML pattern was relatively specific, although most of these cases were at advanced stages. Approximately 40% of ADM patients were found to be in advanced stages of gallbladder cancer, in spite of undergoing periodic follow up.

CONCLUSIONS

This study revealed the difficulty of early diagnosis of primary gallbladder cancer in the setting of concurrent ADM. Current results suggest the possible utility of preventive cholecystectomy for management of asymptomatic ADM patients.

CT and MR features of xanthogranulomatous cholecystitis: an analysis of consecutive 49 cases

OBJECTIVE

To study the CT and MR features of xanthogranulomatous cholecystitis (XGC).

MATERIALS AND METHODS

49 patients had pathologically confirmed XGC. All patients underwent contrast enhanced CT, and 10 patients had additional plain MRI. The CT and MRI results were retrospectively analyzed.

RESULTS

On CT, all patients had thickening of gallbladder wall, with 87.8% cases showed diffuse thickening. 85.7% cases had intramural hypo-attenuated nodules in the thickened wall. Continuous mucosal line and luminal surface enhancement were noted in 79.6% and 85.7% cases, respectively. Gallbladder stones were seen in 69.4% patients. The coexistence of the above 5 CT features was seen in 40% cases, and 80% cases had the coexistence of ≥ 4 features. Diffused gallbladder wall thickening in XGC is more likely to have disrupted mucosal line, and XGC with disrupted mucosal line is more likely to be associated with liver infiltration. In 60% patients the inflammatory process extended beyond gallbladder, with the interface between gallbladder and liver and/or the surrounding fat blurred. 40% cases had an early enhancement of liver parenchyma. Infiltration to other surrounding tissues included bowel (n=3), stomach (n=2), and abdominal wall (n=1). On MR images, 7 of 9 intramural nodules in 7 subjects with T1-weighted dual echo MR images showed higher signal intensity on in-phase images than out-of-phase images.

CONCLUSION

Coexisting of diffuse gallbladder wall thickening, hypo-attenuated intramural nodules, continuous mucosal line, luminal surface enhancement, and gallbladder stone highly suggest XGC. XGC frequently infiltrate liver and surrounding fat. Chemical-shift MRI helps classifying intramural nodules in the gallbladder wall.

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

OBJECTIVES

To evaluate the diagnostic performance of transabdominal high-resolution ultrasound (HRUS) for differentiation of adenomyomatosis from early-stage, wall-thickening-type gallbladder (GB) cancer.

METHODS

HRUS was defined as the addition of high megahertz imaging to conventional low megahertz imaging with use of state-of-the-art imaging technology. HRUS findings were retrospectively compared in 45 patients with adenomyomatosis and 28 patients with stage T1/T2 wall-thickening-type GB cancer. For evaluating HRUS performance in the differential diagnosis of adenomyomatosis from GB cancer, receiver operating characteristic curve analysis was used with a five-point confidence scale independently scored by three blinded radiologists who also analysed morphological abnormalities.

RESULTS

The area under the receiver operating characteristic curve (A (z)) values of HRUS in the diagnosis of adenomyomatosis were 0.948, 0.915 and 0.917 for reviewers 1, 2 and 3. Symmetrical wall thickening, intramural cystic spaces, intramural echogenic foci and twinkling artefacts were significantly associated with adenomyomatosis (P < 0.05), whereas irregular thickening of the outer wall, focal innermost hyperechoic layer (IHL) discontinuity, IHL irregularity, IHL thickening greater than 1 mm, loss of multilayer pattern in the GB wall, and intralesional vascularity were significantly associated with cancer (P < 0.05). The sensitivity, specificity and accuracy of intramural cystic spaces/echogenic foci for the diagnosis of adenomyomatosis were 80.0 %, 85.7 % and 82.2 %.

CONCLUSIONS

This study showed that HRUS can be helpful for distinguishing adenomyomatosis from early-stage, wall-thickening-type GB cancer.

High b-value diffusion-weighted magnetic resonance imaging for gallbladder lesions: differentiation between benignity and malignancy

BACKGROUND

Recently, the clinical application of diffusion-weighted magnetic resonance imaging (DWI) has been expanding to abdominal organs. However, only a few studies on gallbladder diseases have been published. The aim of this study was to evaluate the usefulness and limitations of high b-value DWI for gallbladder diseases.

METHODS

A total of 153 patients (mean age 60 ± 15 years, 78 males) who had undergone DWI for evaluating gallbladder wall thickening or polypoid lesions were included in this study. Of these 153 patients, 36 had gallbladder cancer and 117 had benign gallbladder diseases (67 chronic cholecystitis, 44 adenomyomatosis, four cholesterol polyp, one gallbladder adenoma, and one xanthogranulomatous cholecystitis). We evaluated the positive signal rate with DWI and the apparent diffusion coefficient (ADC) value of each disease.

RESULTS

The positive signal rate with DWI was significantly higher in gallbladder cancer (78 %) than in benign gallbladder diseases (22 %) (p < 0.001). The mean ADC value of gallbladder cancer was (1.83 ± 0.69) × 10(-3) mm(2)/s and that of benign gallbladder diseases was (2.60 ± 0.54) × 10(-3) mm(2)/s (p < 0.001). Benign gallbladder diseases with acute cholecystitis or a history of that had a higher positive signal rate with DWI (p < 0.001) and a lower ADC value (p = 0.018) than those without such conditions.

CONCLUSION

DWI can contribute to the improvement of the diagnostic capability for gallbladder wall thickening or polypoid lesions by compensating for weaknesses of other modalities by its many advantages, although cases with acute cholecystitis or such history sometimes show false-positive on DWI.

Diagnosis and management of gallbladder cancer

Gallbladder cancer (GBC) is a rather uncommon disease, but at the time when it gives symptoms it has usually reached no longer curable stage. Therefore, all attempts must be made to make the diagnosis earlier to have better opportunity for cure. The author searched PubMed, and reviewed literatures on diagnoses and treatment of GBC.

Adenomyomatosis of the gallbladder--case report

Adenomyomatosis of the gallbladder is a benign, mostly asymptomatic condition of an unknown aetiology. Hyperplastic changes in the gallbladder wall cause an overgrowth of the mucosa, thickening of the muscular wall, and formation of intramural diverticula or sinus tracts termed Rokitansky-Aschoff sinuses. Adenomyomatosis is divided on general, segmental and localised. Ultrasound examination, computerized tomography and magnetic resonance are used in diagnostic procedure. The importance of the disease lies in the fact that it can cause recurrent right upper quadrant pain so it must be concerned in resolving pain cause. This paper was aimed at explaining the aetiology of the disease, its clinical manifestation, making diagnosis and therapy in order to make its diagnosis and treatment possible.

Analysis of enhancement pattern of flat gallbladder wall thickening on MDCT to differentiate gallbladder cancer from cholecystitis

OBJECTIVE

The objective of our study was to determine the diagnostic value of analyzing the pattern of gallbladder wall enhancement on MDCT to characterize diffuse gallbladder wall thickening as benign or malignant.

MATERIALS AND METHODS

MDCT scans obtained during the portal venous phase in 78 patients with gallbladder wall thickening caused by various pathologic conditions were retrospectively reviewed by two blinded observers. The CT features of benign and malignant gallbladder wall thickening were compared by means of univariate and multivariate analyses. The study cases were then divided into five patterns according to enhancement pattern. Using these five patterns, two radiologists reviewed the MDCT images and recorded their diagnostic confidence for differentiating benign versus malignant cause on a 5-point scale. The diagnostic performance of CT was evaluated by each observer using a receiver operating characteristic curve analysis.

RESULTS

The thicknesses of the inner and outer layers ("thick" enhancing inner layer > or = 2.6 mm, "thin" outer layer < or = 3.4 mm), strong enhancement of the inner wall, and irregular contour of the affected wall were significant predictors for a malignant cause of gallbladder wall thickening (p < 0.001). The two-layer pattern with a strongly enhancing thick inner layer and weakly enhancing or nonenhancing outer layer and the one-layer pattern with a heterogeneously enhancing thick layer were patterns that were significantly associated with gallbladder cancer (p < 0.05). When we consider those two enhancing patterns as a sign of malignancy, the diagnostic accuracy of MDCT was 89.1% and 87.6% for the two observers, respectively.

CONCLUSION

Analyzing the enhancement pattern of a thickened gallbladder wall on MDCT is helpful in differentiating gallbladder cancer from benign inflammatory diseases.