Contrast-enhanced ultrasound to assess gallbladder polyps

Recent Advances in Endoscopic Ultrasound for Gallbladder Disease Diagnosis

Gallbladder (GB) disease is classified into two broad categories: GB wall-thickening and protuberant lesions, which include various lesions, such as adenomyomatosis, cholecystitis, GB polyps, and GB carcinoma. This review summarizes recent advances in the differential diagnosis of GB lesions, focusing primarily on endoscopic ultrasound (EUS) and related technologies. Fundamental B-mode EUS and contrast-enhanced harmonic EUS (CH-EUS) have been reported to be useful for the diagnosis of GB diseases because they can evaluate the thickening of the GB wall and protuberant lesions in detail. We also outline the current status of EUS-guided fine-needle aspiration (EUS-FNA) for GB lesions, as there have been scattered reports on EUS-FNA in recent years. Furthermore, artificial intelligence (AI) technologies, ranging from machine learning to deep learning, have become popular in healthcare for disease diagnosis, drug discovery, drug development, and patient risk identification. In this review, we outline the current status of AI in the diagnosis of GB.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

SIUMB recommendations on the use of ultrasound in neoplastic lesions of the gallbladder and extrahepatic biliary tract

Extrahepatic biliary tract and gallbladder neoplastic lesions are relatively rare and hence are often underrepresented in the general clinical recommendations for the routine use of ultrasound (US). Dictated by the necessity of updated summarized review of current literature to guide clinicians, this paper represents an updated position of the Italian Society of Ultrasound in Medicine and Biology (SIUMB) on the use of US and contrast-enhanced ultrasound (CEUS) in extrahepatic biliary tract and gallbladder neoplastic lesions such as extrahepatic cholangiocarcinoma, gallbladder adenocarcinoma, gallbladder adenomyomatosis, dense bile with polypoid-like appearance and gallbladder polyps.

Value of Micro Flow Imaging in the Prediction of Adenomatous Polyps

OBJECTIVE

The aim of this study was to assess the value of micro flow imaging (MFI) in distinguishing adenomatous polyps from cholesterol polyps.

METHODS

A total of 143 patients who underwent cholecystectomy for gallbladder polyps were retrospectively analyzed. B-mode ultrasound (BUS), color Doppler flow imaging (CDFI), MFI and contrast-enhanced ultrasound (CEUS) were performed before cholecystectomy. The weighted kappa consistency test was used to evaluate the agreement of vascular morphology among CDFI, MFI and CEUS. Ultrasound image characteristics, including BUS, CDFI and MFI images, were compared between adenomatous polyps and cholesterol polyps. The independent risk factors for adenomatous polyps were selected. The diagnostic performance of MFI combined with BUS in determining adenomatous polyps was compared with CDFI combined with BUS.

RESULTS

Of the 143 patients, 113 cases were cholesterol polyps, and 30 cases were adenomatous polyps. The vascular morphology of gallbladder polyps was more clearly depicted by MFI than CDFI, and it had better agreement with CEUS. Differences in maximum size, height/width ratio, hyperechoic spot and vascular intensity on CDFI and MFI images were significant between adenomatous polyps and cholesterol polyps (p < 0.05). The maximum size, height/width ratio, and vascular intensity on MFI images were independent risk factors for adenomatous polyps. For MFI combined with BUS, sensitivity, specificity and accuracy were 90.00%, 94.69% and 93.70%, respectively. Area under the receiver operating characteristic curve (AUC) of MFI combined with BUS was significantly higher than that of CDFI combined with BUS (AUC = 0.923 vs. 0.784).

CONCLUSION

Compared with CDFI combined with BUS, MFI combined with BUS had higher diagnostic performance in determining adenomatous polyps.

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

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

Value of Conventional Ultrasound-based Scoring System in Distinguishing Adenomatous Polyps From Cholesterol Polyps

BACKGROUND AND AIM

Ultrasound has increased the detection of gallbladder polyps, but it has limitations in evaluating the nature of gallbladder polyps, especially the maximum size of 1.0 to 1.5 cm. We assessed the value of ultrasound scoring system based on independent predictive parameters in distinguishing adenomatous polyps from cholesterol polyps with the maximum size of 1.0 to 1.5 cm.

MATERIALS AND METHODS

We enrolled 163 patients with gallbladder polyps (1.0 to 1.5 cm) who underwent ultrasonography and cholecystectomy. Ultrasound image characteristics were compared between cholesterol polyps and adenomatous polyps in the training cohort from April 2018 to January 2020. An ultrasound scoring system was constructed in the training cohort, and its diagnostic performance was evaluated in the validation cohort from February 2020 to February 2021.

RESULTS

Maximum size, height/width ratio, stone or sludge, vascularity, and hyperechoic spot were significantly different between cholesterol polyps and adenomatous polyps in the training cohort ( P <0.05). The independent predictive parameters for adenomatous polyps were lower height/width ratio, presence of vascularity and absence of hyperechoic spot. The total score was as follows: (height/width ratio, <0.9=4, ≥0.9=0) + (vascularity, present=3, absent=0) + (hyperechoic spot, absent=2, present=0). The sensitivity, specificity and accuracy of ultrasound scoring system ≥5 for diagnosis of adenomatous polyps in the validation cohort were 73.33%, 80.49%, and 78.57%, respectively.

CONCLUSIONS

The ultrasound scoring system aids in distinguishing adenomatous polyps from cholesterol polyps, and effectively decreasing unnecessary cholecystectomy.

[Differential diagnosis of gallbladder polypoid lesions by micro-flow imaging]

OBJECTIVE

To explore the value of micro-flow imaging (MFI) in evaluating blood flow characteristics and differential diagnosis of gallbladder polypoid lesions.

METHODS

We retrospectively analyzed the clinical data and ultrasound images of 73 patients with gallbladder polypoid lesions, including 24 patients with pathologically confirmed neoplastic polyps (n=24) and 49 with non-neoplastic polyps (n=49). All the patients underwent conventional ultrasound, MFI and contrast enhanced ultrasound (CEUS) before cholecystectomy. The blood flow characteristics of the lesions in color Doppler flow imaging (CDFI) and MFI were compared, and the consistency of the findings by these two modalities with those of CEUS were evaluated by weighted Kappa consistency test. The diagnostic performance of MFI for gallbladder polypoid lesions was assessed.

RESULTS

There were significant differences between MFI and CDFI in the evaluation of blood flow characteristics of gallbladder polypoid lesions (χ2=37.684, P < 0.001). MFI showed better performance than CDFI in displaying the blood flow characteristics of the polyps. The consistency in the findings was 0.118 between CDFI and CEUS and 0.816 between MFI and CEUS. The sensitivity, specificity and accuracy of MFI in distinguishing neoplastic polyps from non-neoplastic polyps were 75.00%, 93.88% and 87.67%, respectively.

CONCLUSION

MFI has a good consistency with CEUS in displaying the blood flow characteristics of gallbladder polypoid lesions and can accurately distinguish neoplastic polyps from non-neoplastic polyps, thus providing new ultrasound diagnostic evidence to support clinical decisions on optimal treatments of gallbladder polypoid lesions.