Diffusion-weighted MRI for differentiation of benign from malignant lesions in the gallbladder

Contrast Enhanced CT Versus MRI for Accurate Diagnosis of Wall-thickening Type Gallbladder Cancer

Introduction

Diagnosis of wall-thickening type gallbladder cancer (GBC) is challenging. Computed tomography (CT) and magnetic resonance imaging (MRI) are commonly utilized to evaluate gallbladder wall thickening. However, there is a lack of data comparing the performance of CT and MRI for the detection of wall-thickening type GBC.

Aim

We aim to compare the diagnostic accuracy of CT and MRI in diagnosis of wall-thickening type GBC.

Materials and methods

This prospective study comprised consecutive patients suspected of wall-thickening type GBC who underwent preoperative contrast-enhanced CT and MRI. The final diagnosis was based on the histopathology of the resected gallbladder lesion. Two radiologists independently reviewed the characteristics of gallbladder wall thickening at CT and MRI. The association of CT and MRI findings with histological diagnosis and the interobserver agreement of CT and MRI findings were assessed.

Results

Thirty-three patients (malignancy, 13 and benign, 20) were included. None of the CT findings were significantly associated with GBC. However, at MRI, heterogeneous enhancement, indistinct interface with the liver, and diffusion restriction were significantly associated with malignancy (P = 0.006, <0.001, and 0.005, respectively), and intramural cysts were significantly associated with benign lesions (P = 0.012). For all MRI findings, the interobserver agreement was substantial to perfect (kappa = 0.697-1.000). At CT, the interobserver agreement was substantial to perfect (k = 0.631-1.000).

Conclusion

These findings suggest that MRI may be preferred over CT in patients with suspected wall thickening type GBC. However, larger multicenter studies must confirm our findings.

Multiparametric MR imaging with diffusion-weighted, intravoxel incoherent motion, diffusion tensor, and dynamic contrast-enhanced perfusion sequences to assess gallbladder wall thickening: a prospective study based on surgical histopathology

OBJECTIVE

To investigate the diagnostic performance of a multiparametric magnetic resonance imaging (MRI) protocol comprising quantitative MRI (diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), and dynamic contrast-enhanced (DCE) perfusion MRI) and conventional MRI in the characterization of gallbladder wall thickening (GWT).

METHODS

This prospective study comprised consecutive adults with GWT who underwent multiparametric MRI between July 2020 and April 2022. Two radiologists evaluated the MRI independently. The final diagnosis was based on surgical histopathology. The association of MRI parameters with malignant GWT was evaluated. The area under the curve (AUC) for the quantitative MRI parameters and diagnostic performance of conventional, and multiparametric MRI were compared. The interobserver agreement between two radiologists was calculated.

RESULTS

Thirty-five patients (mean age, 56 years, 23 females) with GWT (25 benign and ten malignant) were evaluated. The quantitative MRI parameters significantly associated with malignant GWT were apparent diffusion coefficient on DWI (p = 0.007) and mean diffusivity (MD) on DTI (p = 0.013), perfusion fraction (f) on IVIM (p = 0.033), time to peak enhancement (TTP, p = 0.008), and wash in rate (p = 0.049) on DCE-MRI. TTP had the highest AUC of 0.790, followed by MD (0.782) and f (0.742) (p = 0.213) for predicting malignant GWT. Multiparametric MRI had significantly higher sensitivity (90% vs. 80%, p = 0.045) than conventional MRI for diagnosing malignant GWT. The two radiologists' reading had substantial to near-perfect agreement (kappa = 0.639-1) and moderate to strong correlation (interclass correlation coefficient = 0.5-0.88).

CONCLUSION

Multiparametric protocol incorporating advanced sequences improved the diagnostic performance of MRI for differentiating benign and malignant GWT.

KEY POINTS

• Multiparametric MRI had 90% sensitivity and 88% specificity for diagnosing malignant GWT, compared to 80% sensitivity and 88% specificity for conventional CE-MRI. • Among the quantitative MRI parameters, TTP (perfusion-MRI) had the highest AUC of 0.790, followed by MD (0.782) and IVIM-f (0.742). • For most quantitative MRI parameters, there was moderate to strong agreement (ICC = 0.5-0.88).

Risk factor analysis and construction of prediction models of gallbladder carcinoma in patients with gallstones

Background

Gallbladder carcinoma (GBC) is a biliary tract tumor with a high mortality rate. The objectives of this study were to explore the risk factors of GBC in patients with gallstones and to establish effective screening indicators.

Methods

A total of 588 patients from medical centers in two different regions of China were included in this study and defined as the internal test samples and the external validation samples, respectively. We retrospectively reviewed the differences in clinicopathologic data of the internal test samples to find the independent risk factors that affect the occurrence of GBC. Then, we constructed three different combined predictive factors (CPFs) through the weighting method, integral system, and nomogram, respectively, and named them CPF-A, CPF-B, and CPF-C sequentially. Furthermore, we evaluated these indicators through calibration and DCA curves. The ROC curve was used to analyze their diagnostic efficiency. Finally, their diagnostic capabilities were validated in the external validation samples.

Results

In the internal test samples, the results showed that five factors, namely, age (RR = 3.077, 95% CI: 1.731-5.496), size of gallstones (RR = 13.732, 95% CI: 5.937-31.762), course of gallstones (RR = 2.438, 95% CI: 1.350-4.403), CEA (RR = 9.464, 95% CI: 3.394-26.392), and CA199 (RR = 9.605, 95% CI: 4.512-20.446), were independent risk factors for GBC in patients with gallstones. Then, we established three predictive indicators: CPF-A, CPF-B, and CPF-C. These models were further validated using bootstrapping with 1,000 repetitions. Calibration and decision curve analysis showed that the three models fit well. Meanwhile, multivariate analysis showed that CPF-B and CPF-C were independent risk factors for GBC in patients with gallstones. In addition, the validation results of the external validation samples are essentially consistent with the internal test samples.

Conclusion

Age (≤58.5 vs. >58.5 years), size of gallstones (≤1.95 vs. >1.95cm), course of gallstones (≤10 vs. >10 years), CEA (≤5 vs. >5 ng/ml), and CA199 (≤37 vs. >37 U/ml) are independent risk factors for GBC in patients with gallstones. When positive indicators were ≥2 among the five independent risk factors or the score of the nomogram was >82.64, the risk of GBC was high in gallstone patients.

Differentiating benign from malignant gallbladder wall thickening in non-contrast MRI imaging: Preliminary study of a combined diagnostic indicator

To synthetically evaluate the diagnostic accuracy of image features for differentiating benign from malignant gallbladder wall thickening disease with non-contrast MRI and establish the optimal diagnostic indicator. A total of 23 patients with wall thickening type gallbladder carcinoma and 61 patients with benign wall thickening disease were included. The diagnostic performance of six image features including the layered pattern on T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) images, T2WI signal intensity, papillary growth, the apparent diffusion coefficient (ADC) value, and the lesion to liver parenchyma ratio (LLR) of gallbladder were evaluated and compared. The receiver operating characteristic (ROC) curve and binary logistic regression analysis were used to construct the optimally combined indicator. All six indicators showed high diagnostic accuracy. The layered pattern on DWI and LLR had the highest area under the curve (AUC) value (0.904), followed by the layered pattern on T2WI (0.883), T2WI signal intensity (0.859), ADC value (0.836), and papillary growth (0.796). There was no statistically significant difference in the AUC among indicators for pairwise comparisons. A combination of layered patterns on DWI and papillary growth was shown to be the optimal indicator by binary logistic regression analysis. The AUC value of the combination (0.972) was higher than the layered pattern on DWI (0.904) and papillary growth (0.796) (P < .001). Non-contrast MRI provides several reliable indicators for differentiating benign from malignant gallbladder thickening disease. The combination of layered patterns on DWI and papillary growth is the optimal indicator.

Computed diffusion-weighted magnetic resonance imaging with high b-values in the diagnosis of gallbladder lesions

PURPOSE

The diagnosis of gallbladder lesions remains challenging. The efficacy of computed diffusion-weighted imaging (DWI) with high b-values and apparent diffusion coefficient (ADC) for the diagnosis of gallbladder cancer remains unknown. We aimed to investigate the usefulness of computed DWI with high b-values and the combination of computed DWI and ADC in differentiating malignant and benign gallbladder lesions.

METHODS

Sixty patients (comprising 30 malignant and 30 benign lesions) who underwent magnetic resonance imaging for gallbladder lesions were included in this retrospective study. Qualitative evaluations were performed using conventional DWI with b1000, computed DWI with b1500, b1000 DWI/ADC, and computed b1500 DWI/ADC, and their diagnostic performances were compared.

RESULTS

The sensitivity, specificity, and accuracy of computed b1500 DWI/ADC were 90% (27/30), 80% (24/30), and 85% (51/60), respectively. The accuracy of computed b1500 DWI/ADC was higher than that of conventional b1000 DWI (52%, 31/60, p < 0.001), computed b1500 DWI (72%, 43/60, p = 0.008), and b1000 DWI/ADC (78%, 47/60, p = 0.125). The specificity of computed b1500 DWI/ADC was also higher than that of conventional b1000 DWI (7%, 2/30, p < 0.001), computed b1500 DWI (47%, 14/30, p = 0.002), and b1000 DWI/ADC (67%, 20/30, p = 0.125). No significant difference was observed in the sensitivity between the groups.

CONCLUSION

This study shows that computed DWI with high b-values combined with ADC can improve diagnostic performance when differentiating malignant and benign gallbladder lesions. Computed diffusion-weighted magnetic resonance imaging with high b-values in the diagnosis of gallbladder lesions. *Computed DWI with b1500 combined with ADC can improve diagnostic performance when differentiating gallbladder lesions compared with conventional methods (b1000 DWI).

Management of Incidentally Detected Gallbladder Polyps: Society of Radiologists in Ultrasound Consensus Conference Recommendations

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue.

Differential diagnoses of gallbladder tumors using CT‐based deep learning

Background

The differential diagnosis between gallbladder cancer (GBC) and xanthogranulomatous cholecystitis (XGC) remains quite challenging, and can possibly lead to improper surgery. This study aimed to distinguish between XGC and GBC by combining computed tomography (CT) images and deep learning (DL) to maximize the therapeutic success of surgery.

Methods

We collected a dataset, including preoperative CT images, from 28 cases of GBC and 21 XGC patients undergoing surgery at our facility. It was subdivided into training and validation (n = 40), and test (n = 9) datasets. We built a CT patch‐based discriminating model using a residual convolutional neural network and employed 5‐fold cross‐validation. The discriminating performance of the model was analyzed in the test dataset.

Results

Of the 40 patients in the training dataset, GBC and XGC were observed in 21 (52.5%), and 19 (47.5%) patients, respectively. A total of 61 126 patches were extracted from the 40 patients. In the validation dataset, the average sensitivity, specificity, and accuracy were 98.8%, 98.0%, and 98.5%, respectively. Furthermore, the area under the receiver operating characteristic curve (AUC) was 0.9985. In the test dataset, which included 11 738 patches, the discriminating accuracy for GBC patients after neoadjuvant chemotherapy (NAC) (n = 3) was insufficient (61.8%). However, the discriminating model demonstrated high accuracy (98.2%) and AUC (0.9893) for cases other than those receiving NAC.

Conclusion

Our CT‐based DL model exhibited high discriminating performance in patients with GBC and XGC. Our study proposes a novel concept for selecting the appropriate procedure and avoiding unnecessary invasive measures.

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.

Clinical value of diffusion-weighted MRI for differentiation between benign and malignant gallbladder disease: a systematic review and meta-analysis

BACKGROUND

Radiological differentiation between benign and malignant gallbladder disease is important but remains challenging. Furthermore, the clinical value of diffusion-weighted imaging (DWI) remains unclear.

PURPOSE

To determine the value of DWI in discriminating benign from malignant gallbladder disease by conducting a systematic review and meta-analysis.

MATERIAL AND METHODS

The literature was systematically searched. Studies analyzing diagnostic value of DWI in gallbladder disease with histopathology or follow-up as reference standard were included. Study selection and data extraction were done by two reviewers independently. Methodological quality was assessed using the QUADAS-2 tool. Sensitivity and specificity were calculated and displayed in a forest plot. A sensitivity analysis was performed in case of outliers. Pooled sensitivity and specificity of DWI were plotted on a hierarchical summary receiver operating characteristic curve. If available, the added value of DWI to conventional magnetic resonance imaging (MRI) sequences was analyzed.

RESULTS

Out of 2456 articles, eight studies fulfilled the inclusion criteria; 592 patients with 221 malignant lesions were included. Pooled sensitivity and specificity rates were 0.87 and 0.84, respectively. In two studies, diagnostic accuracy rates improved after adding DWI to conventional MRI (64% and 75% for conventional MRI vs. 89% and 94% after combining conventional MRI with DWI). In another study, the area under the curve increased from 0.92 to 0.95.

CONCLUSION

DWI appears to be an accurate imaging technique in discriminating benign from malignant gallbladder disease. To achieve optimal patient care, it should be part of multiparametric MRI and should be combined with other imaging modalities.

The value of diffusion-weighted imaging in diagnosing gallbladder malignancy: performance of a new parameter

AIM

To assess the value of the ratio of signal intensities at high and low b-values (b800/b0 ratio) during diffusion-weighted imaging (DWI) for gallbladder cancer diagnosis.

MATERIALS AND METHODS

All patients presenting with suspicious gallbladder lesions between January 2011 and December 2016 who underwent DWI and histopathological diagnoses of the lesions were assessed.

RESULTS

Thirty-two patients (24 men, eight women) were identified. Eighteen patients had benign gallbladder lesions while 14 had malignant lesions. The mean apparent diffusion coefficient (ADC) value was 1.62 (±0.57)×10^-3 mm²/s for benign cases and 1.27 (±0.39)×10^-3 mm²/s for malignant cases; this difference was not significant (p=0.0773). The mean b800/b0 ratio was 0.31 (±0.19) for benign cases and 0.48 (±0.13) for malignant cases; this difference was significant (p=0.007). The ROC curve for b800/b0 had an AUC of 0.782 (95% confidence interval [CI]: 0.616-0.947) with a sensitivity and specificity of 85.7% and 72.2%, respectively, at a cut-off point of 0.33.

CONCLUSION

The b800/b0 ratio can help differentiate benign and malignant gallbladder lesions and may be more reliable than ADC values in quantitative DWI assessments.

Current update on gallbladder carcinoma

Gallbladder (GB) carcinoma is a relatively rare malignancy and is associated with poor prognosis. Numerous risk factors have been associated with the development of GB carcinoma. GB carcinomas may present as mass lesions replacing the GB, focal or diffuse thickening of the GB wall, and intraluminal mass in the GB. Various benign conditions can mimic GB carcinoma. This article reviews the epidemiology, pathology, clinical findings, imaging features, and management of GB carcinomas.

Clinical practice guidelines for the management of biliary tract cancers 2019: The 3rd English edition

BACKGROUND

The Japanese Society of Hepato-Biliary-Pancreatic Surgery launched the clinical practice guidelines for the management of biliary tract cancers (cholangiocarcinoma, gallbladder cancer, and ampullary cancer) in 2007, then published the 2nd version in 2014.

METHODS

In this 3rd version, clinical questions (CQs) were proposed on six topics. The recommendation, grade for recommendation, and statement for each CQ were discussed and finalized by an evidence-based approach. Recommendations were graded as Grade 1 (strong) or Grade 2 (weak) according to the concepts of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

RESULTS

The 31 CQs covered the six topics: (a) prophylactic treatment, (b) diagnosis, (c) biliary drainage, (d) surgical treatment, (e) chemotherapy, and (f) radiation therapy. In the 31 CQs, 14 recommendations were rated strong and 14 recommendations weak. The remaining three CQs had no recommendation. Each CQ includes a statement of how the recommendations were graded.

CONCLUSIONS

This latest guideline provides recommendations for important clinical aspects based on evidence. Future collaboration with the cancer registry will be key for assessing the guidelines and establishing new evidence.

Gallbladder Carcinoma and Its Differential Diagnosis at MRI: What Radiologists Should Know

Gallbladder carcinoma is the most common cancer of the biliary system. It is challenging to diagnose because patients are often asymptomatic or present with nonspecific symptoms that mimic common benign diseases. Surgical excision is the only curative therapy and is best accomplished at early non-locally advanced stages. Unfortunately, gallbladder cancer often manifests at late locally advanced stages, precluding cure. Early tumors are often incidentally detected at imaging or at cholecystectomy performed for another indication. Typical imaging features of localized disease include asymmetric gallbladder wall thickening, polyps larger than 1.0 cm, and a solid mass replacing the gallbladder lumen. Advanced tumors are often infiltrative and can be confusing at CT and MRI owing to their large size. Determination of the origin of the lesion is paramount to narrow the differential diagnosis but is often challenging. It is important to identify gallbladder cancer and distinguish it from other benign and malignant hepatobiliary processes. Since surgical resection is the only curative treatment option, radiologist understanding and interpretation of pathways of nodal and infiltrative tumor spread can direct surgery or preclude patients who may not benefit from surgery. While both CT and MRI are effective, MRI provides superior soft-tissue characterization of the gallbladder and biliary tree and is a useful imaging tool for diagnosis, staging, and evaluation of treatment response. ^©RSNA, 2020.

Progression to invasive cancer after snare polypectomy of intracholecystic papillary neoplasms during gallbladder stone removal by percutaneous transhepatic choledochoscopy: a case report

Background

Intracholecystic papillary neoplasms (ICPNs) of the gallbladder are rare, preinvasive lesions characterized by an intracholecystic papillary growth that may be associated with invasive adenocarcinoma. The natural history of ICPN is unknown. Here, we report a case of ICPN, highlighting its natural course.

Case presentation

A 79-year-old woman presented to the emergency department with perforated cholecystitis. After percutaneous transhepatic gallbladder drainage, due to the presence of surgical risk factors, we opted to perform gallstone removal through percutaneous transhepatic cholangioscopy instead of cholecystectomy. ICPN, which was accidentally detected after the removal of the gallbladder stones, was also endoscopically removed. After 4 years, the patient came back to the hospital with a large gallbladder mass. After cholecystectomy, pathological examination revealed ICPN with invasive adenocarcinoma.

Conclusion

The current case showed endoscopic findings of ICPN and its natural progression, particularly its clinicopathological features and outcomes.

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.

Scoring System to Predict pt2 in Gallbladder Cancer Based on Carcinoembryonic Antigen and Tumor Diameter

BACKGROUND AND AIMS

T2 gallbladder cancer requires lymph node dissection for curative resection, whereas simple cholecystectomy is adequate to treat T1 gallbladder cancer. Hence, this study aimed to develop an accurate scoring system to preoperatively predict pT2 in gallbladder cancer.

MATERIAL AND METHODS

We retrospectively assessed data from 57 patients with suspected gallbladder cancer who underwent curative resection between September 2003 and May 2017. Six with apparent invasion of adjacent organs on preoperative images were excluded. We evaluated preoperative computed tomography, magnetic resonance and endoscopic ultrasonographic images, blood biochemistry, and the maximum standard uptake value in fluorodeoxyglucose-positron emission tomography images. We analyzed whether correlations between preoperative findings and the depth of tumor invasion could predict pT2.

RESULTS

The pathological diagnosis was gallbladder cancer in 30 (58.8%) patients, of whom 21 (69.9%) had pT2 or worse. Multivariate analyses selected carcinoembryonic antigen and tumor diameter as independent predictors of pT2 or worse (odds ratios = 1.741 and 1.098, respectively; 95% confidence intervals = 1.004-3.020 and 1.008-1.197, respectively). A regression formula was created using carcinoembryonic antigen and tumor diameter to calculate pT2 predictive scores. The area under the receiver operating characteristics curve of the pT2 predictive score was 0.873.

CONCLUSION

We created a scoring system to predict pT2 in gallbladder cancer using carcinoembryonic antigen and tumor diameter. The present findings suggested that carcinoembryonic antigen is important for the preoperative evaluation of gallbladder cancer.

Histopathological Examination of Gallbladder Specimens in Kumaon Region of Uttarakhand

Gall stones are one of the major causes of morbidity and mortality all over the world and common health problems throughout in developing countries. Cholecystectomy is one of the most common surgical practices and postoperative analysis of cholecystectomy specimen has a great value since histopathological reports may document some entities with significant clinical significances. Gallbladder carcinomas in cholecystectomy specimens are received in our histopathology laboratory to analyse their clinicopathological features. This was a descriptive study carried out at the histopathology section of the Department of Pathology at our hospital over a period of two years ranging from November 2016 to October 2018. Both intraoperative and postoperative histological examinations of the excised gallbladder facilitated the diagnosis of gallbladder cancer. Surgery-related variables and surgical approaches were evaluated according to the extent of tumor invasion. Twenty five cholecystectomy specimens of the acute and symptomatic chronic cholecystitis patients were analyzed. Standardization of the reporting were examined. Age, gender, presence of gall stone, cholesterolosis, adenomatous hyperplasia, gastric or intestinal metaplasia, dysplasia, histopathological type of gallbladder carcinoma, cellular differentiation, grading, lympho vascular invision, perineural invasion, lymph node invasion, involvement of cystic duct end margin, liver invasion, omental tissue invasion and T.N.M. staging were investigated. Reported rates of histopathological findings were comparable between patients aged twenty six years to seventy six years. Epithelial hyperplasia and metaplasia were found to be related to age. The correlation between cholesterolosis and gender or metaplasia was noted. We suggest that in India and other nations, high incidences of gallbladder carcinoma, all cholecystectomy specimens must be submitted to routine macroscopic and histopathology examination in the laboratory, as this is the only capability through which malignancies can be detected at an early, potentially curable stage. This incidental finding has altered the management and outcome of this dreadful disease.

Usefulness of noncontrast MRI in differentiation between gallbladder carcinoma and benign conditions manifesting as focal mild wall thickening

BACKGROUND

Magnetic resonance imaging (MRI) is a reliable imaging tool for evaluating gallbladder carcinoma, but it is costly and time-consuming.

PURPOSE

To compare noncontrast MRI with multidetector row CT (MDCT) and gadoxetic acid-enhanced whole MRI in distinguishing gallbladder carcinoma from benign disease.

MATERIALS AND METHODS

101 patients (36 with gallbladder carcinoma and 65 with benign disease) with mild focal gallbladder wall thickening were included. Two radiologists reviewed the MDCT and MRI to determine the differential features between malignancy and benignity. Then, the diagnostic performance of MDCT and MRI (T1-, T2- and diffusion-weighted images) with and without gadoxetic acid enhancement in the diagnosis of gallbladder carcinoma was evaluated.

RESULTS

The benign group more often showed T2 necklace sign or T2 hyperintensity within the thickened wall (P < 0.0001) and T1 hyperintensity within the wall or gallbladder lumen (P = 0.0002). Meanwhile, malignancy more frequently showed T2 moderate hyperintensity of the thickened wall, papillary appearance, and diffusion restriction (all P < 0.0001). There were significant differences in sensitivity (79.2% vs 98.6% for observer 1; 84.7% vs 100% for observer 2) and specificity (80.7% vs 96.9%; 79.2% vs 95.4%) between the MDCT and noncontrast MRI (P < 0.05). We found similar diagnostic values between the noncontrast MRI and whole MRI (P = 0.479-1.000) for both observers.

CONCLUSION

Noncontrast MRI could be a useful alternative to gadoxetic acid-enhanced MRI in the diagnosis of gallbladder carcinoma that presents as mild gallbladder wall thickening on MDCT.

Diagnostic performance of diffusion-weighted imaging for differentiating benign and malignant gallbladder lesions: A systematic review and meta-analysis

BACKGROUND

Although diffusion-weighted imaging (DWI) has been characterized as an alternative imaging modality for gallbladder (GB) lesions, it has not been routinely used in clinical practice because of relatively low signal-to-noise ratio.

PURPOSE

To assess the sensitivity and specificity of the diagnostic performance of DWI for differentiating benign and malignant GB lesions.

STUDY TYPE

Meta-analysis.

POPULATION

Patients with GB lesions.

FIELD STRENGTH/SEQUENCE

DWI at 3.0T or 1.5T.

ASSESSMENT

PubMed and EMBASE were searched following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy guidelines.

STATISTICAL TESTS

Bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) modeling were performed to compare the overall diagnostic performance of DWI. Subgroup analyses were performed for qualitative and quantitative assessment of the DWI. Meta-regression analyses were performed according to the characteristics of the patients, study, and MRI.

RESULTS

Eight studies (including 557 patients) were included. The DWI exhibited a pooled sensitivity of 91%, a pooled specificity of 87%, and HSROC of 0.95. In subgroup analyses, qualitative assessment (sensitivity, 90%; specificity, 87%; HSROC, 0.94) was more accurate than quantitative assessment (sensitivity, 82%; specificity, 86 %; HSROC, 0.88). On meta-regression analysis, studies that used 3.0T field strength and thinner slices (≤5 mm) reported a significantly higher sensitivity (P ≤ 0.02) than those using only 1.5T field strength and thicker slices (>5 mm).

DATA CONCLUSION

DWI can discriminate malignant from benign GB lesions with excellent diagnostic performance in both qualitative and quantitative assessments. To enhance the diagnostic ability of DWI, images obtained with thinner slices (≤5 mm) with 3T field strength and qualitative assessment are recommended.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1375-1388.

Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion for the diagnosis of acute cholecystitis

Prompt and accurate diagnosis is critical in the treatment of acute cholecystitis. Diffusion-weighted whole-body magnetic resonance imaging with background body signal suppression/T2 image fusion (DWIBS/T2) identifies areas with high signal intensity, corresponding to inflammation. In the present study, the records and images of patients with acute cholecystitis who underwent DWIBS/T2 between January 2013 and March 2014 were retrospectively analyzed. A total of 11 patients with acute cholecystitis were enrolled. In one patient, DWIBS/T2 identified a thickened wall and high signal intensity, with high signal intensity in the pericholecystic space that suggested localized peritonitis. Positive DWIBS/T2 results indicating acute cholecystitis were obtained in 10/11 patients, with a sensitivity of 90.9%. In addition, wall thickening and high signal intensity were absent in DWIBS/T2 images when wall thickening was not detected by computed tomography. Wall thickening and high signal intensity was attenuated when patients with acute cholecystitis were clinically treated. These data suggest that a thickened gallbladder wall and high signal intensity are indicative of acute cholecystitis and that DWIBS/T2 may be a useful technique in evaluating the severity of acute cholecystitis.

A Case of Intracystic Papillary Neoplasm With an Associated Invasive Adenocarcinoma

Intracystic papillary neoplasm (ICPN) is a preinvasive neoplasm of the gallbladder. Preoperative discrimination between ICPN and gallbladder cancer (GC) is difficult. The standard surgical strategy for ICPN has not yet been established. Herein, we report a case of ICPN with an associated invasive adenocarcinoma. A gallbladder tumor was detected by abdominal ultrasonography in an asymptomatic 69-year-old man, and he was referred to our hospital. Although computed tomography (CT), endoscopic ultrasonography, and magnetic resonance imaging findings in the present case were similar to those for GC, positron emission tomography-CT revealed that fluorodeoxyglucose (FDG) did not accumulate within the tumor. These imaging features suggested that patient was suspected to have GC with serosal invasion, and he underwent extended cholecystectomy and D2 lymph node dissection. He did not develop any postoperative complications, and he was discharged on postoperative day 7. There was no evidence of recurrence for 20 months after surgery. Histopathologic examination confirmed ICPN with an associated invasive adenocarcinoma. Because a previous study reported that almost half of ICPNs more than 1.0 cm in size often developed invasive cancer as our case, ICPNs more than 1.0 cm should be suspected of developing invasive carcinoma regardless of positive or negative accumulation of FDG.

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.

Diffusion-weighted magnetic resonance imaging to differentiate malignant from benign gallbladder disorders

PURPOSE

To retrospectively evaluate the utility of apparent diffusion coefficient (ADC) and lesion to spinal cord ratio (LSR) in diffusion-weighted magnetic resonance (MR) imaging (DWI) as compared with morphological assessment alone, for differentiating malignant from benign gallbladder disorders.

METHODS

This study was approved by the ethics committee, and written informed consent was waived. Ninety-one patients (13 malignancy and 78 benignancy) were reviewed. ADC was calculated using two DW images with different motion-probing gradient strengths (b=0, 1000s/mm(2)). LSR was measured by dividing the signal intensity of a thickened gallbladder wall by the maximum signal intensity of the lumbar enlargement of the spinal cord. In addition, the morphology of the gallbladders was assessed with conventional MR imaging.

RESULTS

In receiver operating characteristic curve analysis, the areas under the curves for ADC and LSR were 0.861 and 0.906, respectively. Three morphological findings were considered: a massive formation, a disrupted mucosal line, and the absence of a two-layered pattern. When a combination of two or more of these morphological findings was positive for malignancy, the sensitivity, specificity, and accuracy were 76.9%, 84.0%, and 83.0%, respectively. When a combination of three or more of the above morphological findings together with ADC of less than 1.2 × 10(-3)mm(2)/s or LSR of more than 0.48 were positive for malignancy, these values were 73.0%, 96.2%, and 92.9%, respectively. There were significant differences in specificity and accuracy.

CONCLUSION

Use of ADC and LSR in DWI can improve diagnostic performance for differentiating malignant from benign gallbladder disorders.

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.

Diffusion-weighted magnetic resonance imaging in cancer: Reported apparent diffusion coefficients, in-vitro and in-vivo reproducibility

There is considerable disparity in the published apparent diffusion coefficient (ADC) values across different anatomies. Institutions are increasingly assessing repeatability and reproducibility of the derived ADC to determine its variation, which could potentially be used as an indicator in determining tumour aggressiveness or assessing tumour response. In this manuscript, a review of selected articles published to date in healthy extra-cranial body diffusion-weighted magnetic resonance imaging is presented, detailing reported ADC values and discussing their variation across different studies. In total 115 studies were selected including 28 for liver parenchyma, 15 for kidney (renal parenchyma), 14 for spleen, 13 for pancreatic body, 6 for gallbladder, 13 for prostate, 13 for uterus (endometrium, myometrium, cervix) and 13 for fibroglandular breast tissue. Median ADC values in selected studies were found to be 1.28 × 10(-3) mm(2)/s in liver, 1.94 × 10(-3) mm(2)/s in kidney, 1.60 × 10(-3) mm(2)/s in pancreatic body, 0.85 × 10(-3) mm(2)/s in spleen, 2.73 × 10(-3) mm(2)/s in gallbladder, 1.64 × 10(-3) mm(2)/s and 1.31 × 10(-3) mm(2)/s in prostate peripheral zone and central gland respectively (combined median value of 1.54×10(-3) mm(2)/s), 1.44 × 10(-3) mm(2)/s in endometrium, 1.53 × 10(-3) mm(2)/s in myometrium, 1.71 × 10(-3) mm(2)/s in cervix and 1.92 × 10(-3) mm(2)/s in breast. In addition, six phantom studies and thirteen in vivo studies were summarized to compare repeatability and reproducibility of the measured ADC. All selected phantom studies demonstrated lower intra-scanner and inter-scanner variation compared to in vivo studies. Based on the findings of this manuscript, it is recommended that protocols need to be optimised for the body part studied and that system-induced variability must be established using a standardized phantom in any clinical study. Reproducibility of the measured ADC must also be assessed in a volunteer population, as variations are far more significant in vivo compared with phantom studies.

Diffusion-weighted magnetic resonance imaging of gallbladder adenocarcinoma: analysis with emphasis on histologic grade

PURPOSE

To investigate the value of diffusion-weighted imaging (DWI) for differentiating gallbladder adenocarcinoma from adenoma, and predicting histologic grades of gallbladder adenocarcinoma.

MATERIALS AND METHODS

Fourty-three gallbladder adenocarcinomas and 8 adenomas were included. We compared apparent diffusion coefficient (ADC) values between adenocarcinoma and adenoma, and ADC values of gallbladder adenocarcinoma among the histologic grade.

RESULTS

Gallbladder adenocarcinoma (1.041×10(-3)mm(2)/s) showed significantly lower ADC values than adenoma (2.039×10(-3)mm(2)/s) (P<.001). Well-differentiated adenocarcinoma (1.290×10(-3)mm(2)/s) showed significantly higher ADC values than higher-grades (1.104×10(-3) and 0.915×10(-3)mm(2)/s in moderately- and poorly-differentiated, respectively) (P<.001).

CONCLUSION

DWI can help to differentiate gallbladder adenocarcinoma from adenoma, and well-differentiated from higher-grade adenocarcinoma.

Utility of diffusion-weighted MRI for differentiating acute from chronic cholecystitis

PURPOSE

To assess the use of diffusion-weighted imaging (DWI) for differentiating acute from chronic cholecystitis, in comparison with conventional magnetic resonance imaging (MRI) features.

MATERIALS AND METHODS

Liver MRI including DWI (b-values 0/500/1000s/mm(2) ) was performed at 1.5T ≤30 days before cholecystectomy in 83 patients with abdominal pain. Two radiologists assessed cases for conventional (gallstones, wall thickening, pericholecystic fluid, pericholecystic fat changes, gallbladder distension, pericholecystic liver enhancement, mural T2 -hyperintensity, mural hyperenhancement, mural striations, abscess, intraluminal membranes, and mural defect) and DWI (increased mural signal on high b-value images, visually low apparent diffusion coefficient [ADC], and ADC values) features.

RESULTS

Acute cholecystitis was present in 43%; chronic cholecystitis was present in 57%. Nine of 12 conventional features were more frequent in acute cholecystitis for both readers (P ≤ 0.003). Increased mural signal on high b-value images was more frequent (P < 0.001) in acute than chronic cholecystitis for R1 (92% vs. 32%) and R2 (83% vs. 30%). Sensitivity and specificity of increased signal on high b-value images were: R1, 92%/68%; R2, 83%/70%. Visually low ADC was more frequent in acute cholecystitis for R2 (P < 0.001) but not R1 (P = 0.406); ADC values were not different between groups for either reader (P = 0.104-0.139). Among conventional and DWI features, only increased signal on high b-value DWI was independently associated with acute cholecystitis for both readers (P = 0.006-0.012).

CONCLUSION

Visually increased mural signal on high b-value DWI was highly sensitive and moderately specific for acute cholecystitis, being an independent predictor relative to conventional features for both readers. Although requiring larger studies, DWI (particularly the high b-value images) may have additive value relative to conventional MRI-suspected acute cholecystitis. J. Magn. Reson. Imaging 2016;44:89-97.

Diffusion-weighted magnetic resonance imaging for non-neoplastic conditions in the hepatobiliary and pancreatic regions: pearls and potential pitfalls in imaging interpretation

Potentially, diffusion-weighted magnetic resonance imaging (DWI) can assess the functional information on concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion. DWI in the hepatobiliary and pancreatic regions has demonstrated the usefulness to detect malignant lesions and differentiate them from benign lesions. However, it has been shown more recently that there is some overlap in ADC values for benign and malignant neoplasms. Moreover, some non-neoplastic lesions in the hepatobiliary and pancreatic regions exhibit restricted diffusion on DWI, because of pus, inflammation, or high cellularity. Focal eosinophilic liver disease, hepatic inflammatory myofibroblastic tumor, granulomatous liver disease, acute cholecystitis, xanthogranulomatous cholecystitis, focal pancreatitis, or autoimmune pancreatitis frequently exhibit restricted diffusion on DWI, which may be confused with malignancy in the hepatobiliary and pancreatic regions. Thus, DWI should not be interpreted in isolation, but in conjunction with other conventional images, to avoid the diagnostic pitfalls of DWI. Nevertheless, the presence of diffusion restriction in the non-neoplastic lesions sometimes provides additional information regarding the diagnosis, in problematic patients where conventional images have yielded equivocal findings. DWI may help differentiate hepatic abscess from malignant necrotic tumors, gallbladder empyema from dense bile or sludge in the gallbladder, and pylephlebitis from bland thrombosis in the portal vein. Therefore, knowledge of DWI findings to conventional imaging findings of diffusion-restricted non-neoplastic conditions in the hepatobiliary and pancreatic regions helps establishing a correct diagnosis.

Gallbladder Cancer in the 21st Century

Gallbladder cancer (GBC) is an uncommon disease in the majority of the world despite being the most common and aggressive malignancy of the biliary tree. Early diagnosis is essential for improved prognosis; however, indolent and nonspecific clinical presentations with a paucity of pathognomonic/predictive radiological features often preclude accurate identification of GBC at an early stage. As such, GBC remains a highly lethal disease, with only 10% of all patients presenting at a stage amenable to surgical resection. Among this select population, continued improvements in survival during the 21st century are attributable to aggressive radical surgery with improved surgical techniques. This paper reviews the current available literature of the 21st century on PubMed and Medline to provide a detailed summary of the epidemiology and risk factors, pathogenesis, clinical presentation, radiology, pathology, management, and prognosis of GBC.

Thymoma of the Left Thymic Lobe with a Contralateral Small Pleural Implant Successfully Detected with Diffusion-weighted MRI

Thymoma is the most common primary neoplasm of the anterior mediastinum. At diagnosis, up to 40% of patients present with advanced disease. Because advanced thymomas receive neoadjuvant chemotherapy, diagnostic imaging is crucial to plan the correct treatment. For characterizing thymomas, CT is the first choice modality, whereas 18F-FDG/PET is reserved for questionable cases and MRI is not routinely employed. Hereby, we describe a case of thymoma with a single contralateral pleural implant in a 30-year-old woman. The small pleural thickening detected at CT was correctly interpreted as pleural seeding related to thymoma at diffusion-weighted (DW)-MRI after a negative 18F-FDG/PET scan, and was subsequently confirmed at surgery. Precise diagnosis and accurate preoperative staging are crucial in managing thymic epithelial tumours in order to design the appropriate treatment and improve prognosis. Indeed, when stage IVa for pleural seeding is diagnosed preoperatively, a multimodality approach including primary chemotherapy followed by surgery and postoperative radiotherapy/chemotherapy is recommended. This is the first report that used DW-MRI for the characterization of pleural seeding in thymoma and demonstrates that DW-MRI could be useful for the correct pre-operatory staging in thymoma patients, especially in cases with indeterminate pleural thickenings at CT, in order to define the correct management.

Optical diagnosis of gallbladder cancers via two-photon excited fluorescence imaging of unstained histological sections

Two-photon excited fluorescence (TPEF) microscopy, based on signal from cells, can provide detailed information on tissue architecture and cellular morphology in unstained histological sections to generate subcellular-resolution images from tissue directly. In this paper, we used TPEF microscopy to image microstructure of human normal gallbladder and three types of differentiated carcinomas in order to investigate the morphological changes of tissue structure, cell, cytoplasm, and nucleus without hematoxylin and eosin (H&E) staining. It displayed that TPEF microscopy can well image the stratified normal gallbladder tissue, including the mucosa, the muscularis, and the serosa. The typical cancer cell, characterized by cellular and nuclear pleomorphism, enlarged nuclei, and augmented nucleolus, can be identified in histological sections without H-E staining as well. The quantitative results showed that the areas of the nucleus and the nucleolus in three types of cancerous cells were all significantly greater than those in normal gallbladder columnar epithelial cells derived from TPEF microscopic images. The studies demonstrated that TPEF microscopy has the ability to characterize tissue structures and cell morphology of gallbladder cancers differentiated from a normal gallbladder in a manner similar to traditional histological analysis. As a novel tool, it has the potential for future retrospective studies of tumor staging and migration by utilizing histological section specimens without H-E staining.