Endoscopic sonography in the diagnosis of gallbladder wall lesions in patients with gallstones

Imaging based flowchart for gallbladder polyp evaluation

BACKGROUND

Preoperative differentiation between neoplastic and nonneoplastic gallbladder polyps, and the subsequent indication for cholecystectomy remains a clinical dilemma. The current 1 cm size threshold for neoplasia is unspecific. The aim of this study was to improve diagnostic work-up for gallbladder polyps using sonographic and MRI characteristics of neoplastic and nonneoplastic polyps.

METHODS

A prospective, exploratory study including patients undergoing cholecystectomy for gallbladder polyp(s) was conducted. Patients underwent targeted transabdominal ultrasound (TAUS) and MRI. Outcomes were sensitivity and specificity for polyp diagnosis, and the radiological characteristics of neoplastic and nonneoplastic polyp types. Histopathology after cholecystectomy was used as reference standard.

RESULTS

Histopathology demonstrated gallbladder polyps in 20/27 patients (74%): 14 cholesterol polyps, three adenomyomatosis, two adenomas and one gastric heterotopia. Sensitivity of polyp identification were 72% (routine TAUS) and 86% (targeted TAUS and MRI). Both adenomas were identified as neoplastic on targeted TAUS and MRI. Sonographic presentation as multiple, pedunculated polyps, either heterogeneous or with hyperechoic foci, or as single polyps containing cysts were limited to nonneoplastic polyps. On MRI hyperintense polyps on T1-weighted image were cholesterol polyps. An adenoma with high-grade dysplasia showed foci of decreased ADC values. We propose a checklist for polyp evaluation by targeted TAUS and a flowchart for radiological work-up of gallbladder polyps.

CONCLUSIONS

The presented checklist and flowchart could aid diagnostic work-up for gallbladder polyps compared to current routine ultrasound, by elimination of nonneoplastic polyps and ultimately improve treatment decision for patients with gallbladder polyps.

Interobserver Reliability of Endoscopic Ultrasonography: Literature Review

Endoscopic ultrasonography (EUS) has been applied to the diagnosis of various digestive disorders. Although it has been widely accepted and its diagnostic value is high, the dependence of EUS diagnosis on image interpretation done by the endosonographer has persisted as an important difficulty. Consequently, high interobserver reliability (IOR) in EUS diagnosis is important to demonstrate the reliability of EUS diagnosis. We reviewed the literature on the IOR of EUS diagnosis for various diseases such as chronic pancreatitis, pancreatic solid/cystic mass, lymphadenopathy, and gastrointestinal and subepithelial lesions. The IOR of EUS diagnosis differs depending on the disease; moreover, EUS findings with high IOR and those with IOR that was not necessarily high were used as diagnostic criteria. Therefore, to further increase the value of EUS diagnosis, EUS diagnostic criteria with high diagnostic characteristics based on EUS findings with high IOR must be established.

The role of endoscopic ultrasound in the diagnosis of gallbladder diseases

Endoscopic ultrasound (EUS) has recently played an increasing role in the diagnosis of gallbladder diseases. This review aims to summarize the role of EUS in the diagnosis of gallbladder lesions. EUS provides high-resolution images that can improve the diagnosis of gallbladder polypoid lesions and microlithiasis, in addition to evaluating gallbladder thickness and staging of gallbladder carcinoma. Contrast-enhancing agents may be useful for the differential diagnosis of gallbladder lesions, but the evidence of their effectiveness is still limited and further studies are required in this area to establish its usefulness. Endoscopic ultrasound combined with fine needle aspiration has played an increasing role in providing histological diagnosis of gallbladder tumors in addition to gallbladder thickening.

Contrast-enhanced harmonic endoscopic ultrasonography in the differential diagnosis of gallbladder wall thickening

BACKGROUND AND AIMS

Differentiation of gallbladder (GB) carcinoma from benign GB wall thickening is challenging. The recent introduction of second-generation ultrasonic contrast agents has made contrast harmonic imaging with EUS possible. The aim of our study was to evaluate the utility of contrast-enhanced harmonic EUS (CH-EUS) for the differential diagnosis of GB wall thickening.

METHODS

Thirty-six consecutive patients with GB wall thickening imaged by CH-EUS and then underwent surgery were enrolled in this study. After the lesions were observed with conventional harmonic EUS (H-EUS), CH-EUS was performed with intravenous injection of 0.015 ml/kg of Sonazoid. Three reviewers with various levels of experience of EUS (Reviewer A: experienced endosonographer, B: EUS trainee, C: experienced gastroenterologist with expertise in transabdominal ultrasound but no EUS experience) were blinded to findings of recorded video of H-EUS and CH-EUS. The diagnostic accuracy of H-EUS and CH-EUS for malignant GB wall thickening was compared.

RESULTS

Final diagnoses based on surgical histology were GB carcinoma in 16, cholecystitis in 11, adenomyomatosis in 6 and cholesterolosis in 3. Overall sensitivity, specificity and accuracy for diagnosing malignant GB wall thickening of H-EUS and CH-EUS were 83.3 versus 89.6, 65 versus 98% (p < 0.001) and 73.1 versus 94.4% (p < 0.001). The inter-observer agreement for H-EUS was moderate (κ = 0.51), whereas that for CH-EUS was substantial (κ = 0.77). The inhomogeneous enhanced pattern on CH-EUS was a strong predictive factor of malignant GB wall thickening.

CONCLUSION

CH-EUS has the potential to improve the preoperative diagnostic accuracy and inter-observer agreement in the differential diagnosis of GB wall thickening.

Differential diagnostic and staging accuracies of high resolution ultrasonography, endoscopic ultrasonography, and multidetector computed tomography for gallbladder polypoid lesions and gallbladder cancer

OBJECTIVE

The authors undertook to investigate the diagnostic performance of high-resolution ultrasound (HRUS), and to compare the differential diagnostic and staging accuracies of endoscopic ultrasonography (EUS), HRUS, and multidetector computed tomography for gallbladder (GB) polypoid lesions and GB cancer.

SUMMARY OF BACKGROUND DATA

Endoscopic ultrasonography was considered the most sensitive diagnostic modality for GB polypoid lesions. However, recent technical advancements in other image modalities including conventional sonography (US) allow the production of comparable images.

METHODS

A total of 170 patients, with a more than 1-cm sized polypoid GB lesion, and without evidence of definite local invasion to adjacent organs during primary screening, were consecutively enrolled in this prospective, blind, comparative study. After excluding 26 patients with inappropriate medical histories, 144 patients were finally enrolled. All patients underwent surgical resection. Clinical diagnoses were compared with histopathologic findings by diagnostic modality.

RESULTS

Of the 144 patients, there were 115 (79.8%) cases of benign GB polypoid lesions and 29 (20.2%) cases of GB cancers. Diagnostic sensitivities for malignancy were 90% for HRUS, 86% for EUS, and 72% for CT. When evaluating the abilities of these modalities to predict GB cancer depth of invasion, we excluded 2 unusual GB malignancies (melanoma and lymphoma), HRUS was found to have the highest diagnostic accuracy of 62.9%; EUS and CT had accuracies of 55.5% and 44.4%, respectively.

CONCLUSIONS

The diagnostic accuracies of HRUS and EUS for the differential diagnosis of GB polypoid lesions were comparable. In view of patient comfort and no requirement for sedation, we consider that HRUS is likely to become an important diagnostic modality for the differential diagnosis and staging of GB polypoid lesions and early GB cancer.

Endoscopic ultrasonography does not differentiate neoplastic from non-neoplastic small gallbladder polyps

AIM: To assess the ability of endoscopic ultrasonography (EUS) to differentiate neoplastic from non-neoplastic polypoid lesions of the gallbladder (PLGs).

METHODS: The uses of EUS and transabdominal ultrasonography (US) were retrospectively analyzed in 94 surgical cases of gallbladder polyps less than 20 mm in diameter.

RESULTS: The prevalence of neoplastic lesions with a diameter of 5-10 mm was 17.2% (10/58); 11-15 mm, 15.4% (4/26), and 16-20 mm, 50% (5/10). The overall diagnostic accuracies of EUS and US for small PLGs were 80.9% and 63.9% (P < 0.05), respectively. EUS correctly distinguished 12 (63.2%) of 19 neoplastic PLGs but was less accurate for polyps less than 1.0 cm (4/10, 40%) than for polyps greater than 1.0 cm (8/9, 88.9%) (P = 0.02).

CONCLUSION: Although EUS was more accurate than US, its accuracy for differentiating neoplastic from non-neoplastic PLGs less than 1.0 cm was low. Thus, EUS alone is not sufficient for determining a treatment strategy for PLGs of less than 1.0 cm.

[The application of digestive endoscopic ultrasonography in the gallbladder pathology]

A WELL DEFINED PATHOLOGY: Bilary lithiasis and vesicular parietal abnormalities constitute the totality of the gallbladder pathology. The surgical experience and widely current use of digestive imaging, notably ultrasonography, have contributed to enlightening our knowledge of this pathology. POTENTIAL DIAGNOSTIC PROBLEMS: There is no particular problem in the diagnosis of gallbladder lithiasis and its treatment is currently codified. However the discovery of thickened gallbladder wall or polyps increases the fear of gallbladder cancer. A FUNDAMENTAL ROLE FOR ENDOSCOPIC ULTRASONOGRAPHY: Within the framework of screening for cancer, endoscopic ultrasonography, the performance of which in gallbladder pathology has rarely been studied, appears promising. Other than its role in the control of the extension of gallbladder cancers, it provides reliable characterisation of most of the polyps. Hence its place today is unavoidable in the therapeutic decision trees of such affections.

A linear-array freehand 3-D endoscopic ultrasound

Recognition of the clinical importance of linear-array endoscopic ultrasound (EUS) has increased. In this study, we developed a linear-array 3-D EUS, a miniature position sensor attached to the tip of the echoendoscope used in freehand scanning. To evaluate the geometrical accuracy of the 3-D reconstruction of the system, the diameter of a sphere-shaped phantom (38 mm) was determined by five examiners and five measurers. Measured size of the sphere was 39.03 +/- 1.29 mm, with variance between examiners and measurers, and interaction of examiners with measurers was not significant. In animal and clinical studies, the system facilitated anatomical interpretation of the EUS images, especially in the pancreatobiliary area and vascular images. We concluded that this system is both accurate and reproducible, and may resolve difficulties in linear-array EUS.