How Can We Manage Gallbladder Lesions by Transabdominal Ultrasound?

Transabdominal ultrasound evaluation of vascularity of gallbladder lesions: particularly those with wall thickening

Gallbladder wall thickening is relatively common in clinical settings, and for appropriate diagnosis, the size, shape, internal structure, surface contour, and vascularity of the gallbladder wall must be evaluated. Morphological evaluation is the most important; however, some gallbladder lesions resemble gallbladder cancer in imaging studies, making differential diagnosis challenging. Vascular evaluation is indispensable for a precise diagnosis in these cases. In this review, we present the current status of vascular evaluation using US and diagnosis using vascular imaging for gallbladder lesions, including those presenting with wall thickening. To date, several ultrasound imaging techniques have been developed to assess vascularity, including Doppler imaging with high sensitivity, use of contrast agents, and microvascular imaging using a novel filter for Doppler imaging. Although conventional color Doppler imaging is rarely used for the diagnosis of gallbladder lesions, the efficacy of contrast-enhanced ultrasound in assessing the vascularity, enhancement pattern, or timing of enhancement/washout has been reported. Presence of multiple irregular microvessels has been speculated to indicate malignancy. However, few reports on microvessels have been published, and further studies are required for the precise diagnosis of gallbladder lesions with microvascular evaluation.

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.

Reply to Fujimoto, T. Comment on "Okaniwa, S. How Can We Manage Gallbladder Lesions by Transabdominal Ultrasound? Diagnostics 2021, 11, 784"

Thank you for your interesting comments [...].

How Can We Identify T1 or Shallow T2 Gallbladder Carcinoma Using Ultrasound? Comment on Okaniwa, S. How Can We Manage Gallbladder Lesions by Transabdominal Ultrasound? Diagnostics 2021, 11, 784

I am keenly interested in ultrasound diagnosis of the invasion depth of gallbladder carcinoma (GBC) [...].

Biliary Anatomy 2.0 Quiz: Test Your Knowledge

Anatomy has remained an interest of physicians throughout the ages. The biliary tract spans from the liver to the hepatoduodenal mesentery, pancreas, and into the duodenum. Therefore, it is important for not only hepatobiliary surgeons but also general gastrointestinal surgeons, gastroenterologists, radiologists, and pathologists to be familiar with biliary anatomy and its variants. While surgery for hilar cholangiocarcinoma is one of the most challenging procedures, cholecystectomy is one of the most common procedures done from the beginning of surgical training. We hope that by answering the following questions, you will gain a comprehensive understanding of biliary anatomy and a greater appreciation for it.

Imaging patterns of wall thickening type of gallbladder cancer

Gallbladder cancer (GBC) has a high incidence in certain geographical regions. Morphologically, GBC presents as a mass replacing the gallbladder, a polypoidal lesion, or wall thickening. The incidence of preoperative diagnosis of wall thickening type of GBC is less well studied. The patterns of mural involvement and extramural spread are not well described in the literature. Additionally, wall thickening in the gallbladder does not always indicate malignancy and can be secondary to inflammatory or benign gallbladder diseases and extracholecystic causes and systemic pathologies. Objective reporting of gallbladder wall thickening will help us appreciate GBC's early features. In this review, we illustrate the imaging patterns of wall thickening type of GBC.

Development and Validation of a Preoperative Nomogram for Predicting Benign and Malignant Gallbladder Polypoid Lesions

Purpose

The purpose of this study was to develop and validate a preoperative nomogram of differentiating benign and malignant gallbladder polypoid lesions (GPs) combining clinical and radiomics features.

Methods

The clinical and imaging data of 195 GPs patients which were confirmed by pathology from April 2014 to May 2021 were reviewed. All patients were randomly divided into the training and testing cohorts. Radiomics features based on 3 sequences of contrast-enhanced computed tomography were extracted by the Pyradiomics package in python, and the nomogram further combined with clinical parameters was established by multiple logistic regression. The performance of the nomogram was evaluated by discrimination and calibration.

Results

Among 195 GPs patients, 132 patients were pathologically benign, and 63 patients were malignant. To differentiate benign and malignant GPs, the combined model achieved an area under the curve (AUC) of 0.950 as compared to the radiomics model and clinical model with AUC of 0.929 and 0.925 in the training cohort, respectively. Further validation showed that the combined model contributes to better sensitivity and specificity in the training and testing cohorts by the same cutoff value, although the clinical model had an AUC of 0.943, which was higher than 0.942 of the combined model in the testing cohort.

Conclusion

This study develops a nomogram based on the clinical and radiomics features for the highly effective differentiation and prediction of benign and malignant GPs before surgery.

The Role of Endoscopic Ultrasound in the Diagnosis of Gallbladder Lesions

Gallbladder (GB) diseases represent various lesions including gallstones, cholesterol polyps, adenomyomatosis, and GB carcinoma. This review aims to summarize the role of endoscopic ultrasound (EUS) in the diagnosis of GB lesions. EUS provides high-resolution images that can improve the diagnosis of GB polypoid lesions, GB wall thickness, and GB carcinoma staging. Contrast-enhancing agents may be useful for the differential diagnosis of GB lesions, but the evidence of their effectiveness is still limited. Thus, further studies are required in this area to establish its usefulness. EUS combined with fine-needle aspiration has played an increasing role in providing a histological diagnosis of GB tumors in addition to GB wall thickness.

The Role of EUS and EUS-FNA in Differentiating Benign and Malignant Gallbladder Lesions

Endoscopic ultrasonography (EUS) has greater spatial resolution than other diagnostic imaging modalities. In addition, if gallbladder lesions are found and gallbladder cancer is suspected, EUS is an indispensable modality, enabling detailed tests for invasion depth evaluation using the Doppler mode and ultrasound agents. Furthermore, for gallbladder lesions, EUS fine-needle aspiration (EUS-FNA) can be used to differentiate benign and malignant forms of conditions, such as xanthogranulomatous cholecystitis, and collect evidence before chemotherapy. EUS-FNA is also useful for highly precise and specific diagnoses. However, the prevention of bile leakage, an accidental symptom, is highly important. Advancements in next-generation sequencing (NGS) technologies facilitate the application of multiple parallel sequencing to EUS-FNA samples. Several biomarkers are expected to stratify treatment for gallbladder cancer; however, NGS can unveil potential predictive genomic biomarkers for the treatment response. It is believed that NGS may be feasible with samples obtained using EUS-FNA, further increasing the demand for EUS-FNA.