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

Enhancement Patterns of Malignant Gallbladder Masses at Multiphasic Contrast-enhanced CT: Associations With Clinicoradiopathological Features

Purpose

To assess the enhancement patterns of malignant gallbladder masses at multiphasic contrast-enhanced computed tomography (CECT) and their association with the clinicoradiopathological features.

Material and methods

In this retrospective study, consecutive patients with mass-forming gallbladder cancer (GBC) who underwent biphasic [hepatic arterial phase (HAP) and portal venous phase (PVP)] CECT between January 2019 and January 2023 were included. The enhancement patterns at CT scans were assessed independently by two radiologists blinded to the clinicopathological data. The masses were categorized into the typical group (hypoattenuation relative to normal liver in HAP) and the atypical group (isoenhancement or hyperenhancement in HAP). Enhancement patterns in PVP were also evaluated. The association between enhancement characteristics and the pathological grade and type, radiological aggressiveness (biliary/vascular involvement, lymph node, liver, and omental metastases), resectability, and overall survival was assessed.

Results

Sixty-five patients (41 females, mean age was 52.5 ± 17.6 years) were included in the study. On HAP images, eight lesions (12.3%) were hyperattenuating, nine (13.8%) were isoattenuating, and 48 (73.8%) were hypoattenuating. Of the 17 masses in the atypical group, 8 (47.1%) lesions showed washout, and 9 showed persistent enhancement (52.9%) in the PVP. Heterogeneous peripheral and central enhancement in HAP were significantly associated with lymph node metastases (P = 0.019). Enhancement pattern was not significantly associated with pathological grade/type, other radiological features, resectability, and overall survival.

Conclusion

Mass-forming GBC has variable enhancement. Heterogeneous HAP enhancement is associated with lymph node metastases.

Case 329: Intracholecystic Papillary Neoplasm of the Gallbladder

HISTORY

A 45-year-old female patient who was previously healthy presented after several weeks of fullness in the right upper quadrant of the abdomen. The patient did not experience pain, nausea, vomiting, or jaundice, and had no contributory past medical or surgical history, including no history of malignancy. Upon examination, vital signs were within normal limits and the patient appeared well, with soft palpable fullness in the right upper quadrant. The abdomen was nontender and nondistended. Laboratory investigation revealed no abnormalities, with a normal complete blood cell count and normal serum tumor markers that included α-fetoprotein (<2.0 ng/mL; reference, <8.3 ng/mL), cancer antigen 19-9 (21.6 U/mL; reference, <35 U/mL), and carcinoembryonic antigen (1.3 ng/mL; reference, <5 ng/mL). CT of the abdomen and pelvis was performed with intravenous contrast material in the emergency department. Subsequently, combined MRI and MR cholangiopancreatography of the abdomen was performed with and without intravenous contrast material for further evaluation. CT of the chest performed during the same encounter was unremarkable.

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.

Natural products and long noncoding RNA signatures in gallbladder cancer: a review focuses on pathogenesis, diagnosis, and drug resistance

Gallbladder cancer (GBC) is an aggressive and lethal malignancy with a poor prognosis. Long noncoding RNAs (lncRNAs) and natural products have emerged as key orchestrators of cancer pathogenesis through widespread dysregulation across GBC transcriptomes. Functional studies have revealed that lncRNAs interact with oncoproteins and tumor suppressors to control proliferation, invasion, metastasis, angiogenesis, stemness, and drug resistance. Curcumin, baicalein, oleanolic acid, shikonin, oxymatrine, arctigenin, liensinine, fangchinoline, and dioscin are a few examples of natural compounds that have demonstrated promising anticancer activities against GBC through the regulation of important signaling pathways. The lncRNAs, i.e., SNHG6, Linc00261, GALM, OIP5-AS1, FOXD2-AS1, MINCR, DGCR5, MEG3, GATA6-AS, TUG1, and DILC, are key players in regulating the aforementioned processes. For example, the lncRNAs FOXD2-AS1, DILC, and HOTAIR activate oncogenes such as DNMT1, Wnt/β-catenin, BMI1, and c-Myc, whereas MEG3 and GATA6-AS suppress the tumor proteins NF-κB, EZH2, and miR-421. Clinically, specific lncRNAs can serve as diagnostic or prognostic biomarkers based on overexpression correlating with advanced TNM stage, metastasis, chemoresistance, and poor survival. Therapeutically, targeting aberrant lncRNAs with siRNA or antisense oligos disrupts their oncogenic signaling and inhibits GBC progression. Overall, dysfunctional lncRNA regulatory circuits offer multiple avenues for precision medicine approaches to improve early GBC detection and overcome this deadly cancer. They have the potential to serve as novel biomarkers as they are detectable in bodily fluids and tissues. These findings enhance gallbladder treatments, mitigating resistance to chemo- and radiotherapy.

Dual-energy CT in differentiating benign gallbladder wall thickening from wall thickening type of gallbladder cancer

OBJECTIVE

To evaluate the performance of dual-energy computed tomography (DECT) in differentiating non-acute benign from malignant gallbladder wall thickening (GBWT).

METHODS

This prospective study comprised consecutive adults with GBWT who underwent late arterial phase (LAP) and portal venous phase (PVP) DECT between January 2022 and May 2023. The final diagnosis was based on histopathology or 3-6 months follow-up imaging. DECT images in LAP and PVP were assessed independently by two radiologists. The demographic, qualitative, and quantitative parameters were compared between two groups Multivariate logistic regression was performed to determine the association between the aforementioned factors and malignant GBWT.

RESULTS

Seventy-five patients (mean age 56 ± 12.8 years, 46 females) were included. Forty-two patients had benign, and 33 had malignant GBWT. In the overall group, female gender (p = 0.018), lymphadenopathy (p = 0.011), and omental nodules (p = 0.044) were significantly associated with malignant GBWT. None of the DECT features differed significantly between benign and malignant GBWT in overall group. In the xanthogranulomatous cholecystitis (XGC, n = 9) vs. gallbladder cancer (GBC) (n = 33) subgroup, mean attenuation value at 140 keV LAP VMI was significantly associated with malignant GBWT [p = 0.023, area under curve 0.759 (95%CI 0.599-0.919)].

CONCLUSION

DECT-generated quantitative parameters do not add value in differentiating non-acute benign from malignant GBWT. However, DECT may have a role in differentiating XGC from GBC in a selected subgroup of patients. Further, larger studies may be necessary to confirm these findings.

CLINICAL RELEVANCE STATEMENT

In patients with non-acute gallbladder wall thickening in whom there is suspicion of xanthogranulomatous cholecystitis (XGC), DECT findings may allow differentiation of XGC from wall thickening type of gallbladder cancer.

KEY POINTS

Differentiation of benign and malignant gallbladder wall thickening (GBWT) at CT is challenging. Quantitative dual energy CT (DECT) features do not provide additional value in differentiating benign and malignant GBWT. DECT may be helpful in a subgroup of patients to differentiate xanthogranulomatous cholecystitis from gallbladder cancer.

Cholangiocarcinoma of the Common Bile Duct Presenting as Empyema of the Gallbladder: A Rare Case Report

Cholangiocarcinoma of the common bile duct (CBD) presenting as empyema of the gallbladder is a rare entity that poses a risk of septicemia, septic shock, peritonitis, and abscess formation. This case report describes an elderly female presenting with pain in the right hypochondrium, a positive Murphy's sign, and a history of regurgitation and constipation. It highlights the value of imaging in the early diagnosis of this rare presentation of underlying malignancy. The most common cause of empyema of the gallbladder is acute cholecystitis, followed by gallbladder neck obstruction by a calculus. This report discusses the important role of imaging supported by clinical history, examination, laboratory tests, and histopathological findings to diagnose this rare presentation of empyema of the gallbladder as a complication of underlying cholangiocarcinoma. Additionally, it briefly discusses the change in the management line for cholangiocarcinoma patients with complications such as gallbladder perforation and septicemia. The study concludes that the possibility of underlying bile duct malignancy cannot be overlooked in patients with similar symptoms, particularly among the elderly.

Deep-learning enabled ultrasound based detection of gallbladder cancer in northern India: a prospective diagnostic study

Background

Gallbladder cancer (GBC) is highly aggressive. Diagnosis of GBC is challenging as benign gallbladder lesions can have similar imaging features. We aim to develop and validate a deep learning (DL) model for the automatic detection of GBC at abdominal ultrasound (US) and compare its diagnostic performance with that of radiologists.

Methods

In this prospective study, a multiscale, second-order pooling-based DL classifier model was trained (training and validation cohorts) using the US data of patients with gallbladder lesions acquired between August 2019 and June 2021 at the Postgraduate Institute of Medical Education and research, a tertiary care hospital in North India. The performance of the DL model to detect GBC was evaluated in a temporally independent test cohort (July 2021-September 2022) and was compared with that of two radiologists.

Findings

The study included 233 patients in the training set (mean age, 48 ± (2SD) 23 years; 142 women), 59 patients in the validation set (mean age, 51.4 ± 19.2 years; 38 women), and 273 patients in the test set (mean age, 50.4 ± 22.1 years; 177 women). In the test set, the DL model had sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of 92.3% (95% CI, 88.1-95.6), 74.4% (95% CI, 65.3-79.9), and 0.887 (95% CI, 0.844-0.930), respectively for detecting GBC which was comparable to both the radiologists. The DL-based approach showed high sensitivity (89.8-93%) and AUC (0.810-0.890) for detecting GBC in the presence of stones, contracted gallbladders, lesion size <10 mm, and neck lesions, which was comparable to both the radiologists (p = 0.052-0.738 for sensitivity and p = 0.061-0.745 for AUC). The sensitivity for DL-based detection of mural thickening type of GBC was significantly greater than one of the radiologists (87.8% vs. 72.8%, p = 0.012), despite a reduced specificity.

Interpretation

The DL-based approach demonstrated diagnostic performance comparable to experienced radiologists in detecting GBC using US. However, multicentre studies are warranted to explore the potential of DL-based diagnosis of GBC fully.

Funding

None.

Proposal for a new morphological "combined type" of gallbladder cancer: description of radiopathological characteristics and comparison with other morphological types

OBJECTIVE

To describe the radiopathological characteristics of a new morphological "combined type" of gallbladder cancer (GBC) and compare it with the mass replacing gallbladder and thickening types of GBC.

MATERIALS AND METHODS

The imaging and pathological details of consecutive patients with GBC between August 2020 and December 2022 were retrospectively reviewed. Two radiologists reviewed computed tomography/magnetic resonance imaging in consensus for the morphological type of GBC. The radiologists classified GBC as mass replacing gallbladder, wall thickening, and combined type. The combined type was defined as a mass arising from the thickened wall of an adequately distended gallbladder that extended exophytically into the adjacent liver parenchyma. The presence of calculi, site, and size of lesion, biliary/portal vein involvement, liver, lymph node, and omental metastases was compared among the various types. The pathological characteristics were also compared.

RESULTS

Of the 481 patients (median age 55 years, 63.2% females) included in the study, mass replacing gallbladder, wall thickening, and combined-type GBC were seen in 42.8% (206/481), 40.5% (195/481), and 16.6% (80/481) of patients, respectively. In the combined type of GBC, biliary/portal vein involvement was seen in 63.7% (51/80) and 7.5% (6/80) of patients. Liver, lymph node, and omental metastases were seen in 67.5% (54/80), 40% (32/80), and 41.2% (33/80) patients, respectively. Liver metastases were significantly more common in the combined type (p = 0.002). There were no significant differences in pathological characteristics among the various types.

CONCLUSION

Combined-type GBC is less common than the mass replacing gallbladder and thickening types and is associated with a higher risk of liver metastases.

The Many Hidden Faces of Gallbladder Carcinoma on CT and MRI Imaging-From A to Z

Gallbladder carcinoma represents the most aggressive biliary tract cancer and the sixth most common gastrointestinal malignancy. The diagnosis is a challenging clinical task due to its clinical presentation, which is often non-specific, mimicking a heterogeneous group of diseases, as well as benign processes such as complicated cholecystitis, xanthogranulomatous cholecystitis, adenomyomatosis, porcelain gallbladder or metastasis to the gallbladder (most frequently derived from melanoma, renal cell carcinoma). Risk factors include gallstones, carcinogen exposure, porcelain gallbladder, typhoid carrier state, gallbladder polyps and abnormal pancreaticobiliary ductal junction. Typical imaging features on CT or MRI reveal three major patterns: asymmetric focal or diffuse wall-thickening of the gallbladder, a solid mass that replaces the gallbladder and invades the adjacent organs or as an intraluminal enhancement mass arising predominantly from the gallbladder fundus. The tumor can spread to the liver, the adjacent internal organs and lymph nodes. Depending on the disease stage, surgical resection is the curative treatment option in early stages and adjuvant combination chemotherapy at advanced stages. The purpose of this scientific paper is to fully illustrate and evaluate, through multimodality imaging findings (CT and MRI), different presentations and imaging scenarios of gallbladder cancer in six patients and thoroughly analyze the risk factors, patterns of spread and differential diagnosis regarding each particular case.

Sonographic "Cervix Sign": A New Ancillary Sign of Gallbladder Neck Malignancy

Background

The differentiation of benign and malignant gallbladder wall thickening is challenging. The purpose of this study is to evaluate a new sonographic sign, "cervix sign" for differentiation of benign and malignant gallbladder neck thickening.

Methods

This retrospective study comprised consecutive patients with gallbladder neck thickening who underwent sonography between August 2019 and December 2021. The presence of "cervix sign" was assessed by two radiologists independently.

Results

Sixty-five patients had gallbladder neck thickening (28 malignant and 37 benign). The sonographic "cervix sign" was present in 18 (64%) patients with malignant thickening and in only one (2.7%) patient with benign thickening (P = 0.0001). The mean wall thickness was greater, and symmetric wall thickening and liver metastases were more common in malignant thickening with "cervix sign" (without reaching statistical significance). There was substantial agreement (kappa = 0.78) between the two observers for the cervix sign.

Conclusion

Sonographic "cervix sign" is a useful ancillary feature of gallbladder neck cancer.

Xanthogranulomatous cholecystitis in a patient with ulcerative colitis and primary sclerosing cholangitis: A case report

Chronic gallbladder disease due to xanthogranulomatous cholecystitis is uncommon, and its symptoms are generally vague. While there is no firm evidence to link xanthogranulomatous cholecystitis to primary sclerosing cholangitis or ulcerative colitis. The patient is a 41-year-old male with a history of ulcerative colitis, primary sclerosing cholangitis, and biliary stenting who complained of symptoms of anorexia, jaundice, and pruritus. In the initial ultrasound exam, there was evidence of intrahepatic and extra-hepatic bile duct dilation along with a significant and mass-like circumferential thickening of the gallbladder wall. Magnetic resonance cholangiopancreatography was performed for further evaluation, which indicated increased gallbladder wall thickness, containing multiple T2 hyper-signal nodules while the mucosal layer was intact. There was also a filling defect in the common bile duct's distal portion. These findings matched a xanthogranulomatous cholecystitis diagnosis and a possibly malignant lesion in the distal of the common bile duct. The patient ultimately had a cholecystectomy, and pathology findings confirmed the diagnosis of xanthogranulomatous cholecystitis. Biopsy specimens obtained from the distal of the common bile duct lesion were microscopically identified as intramucosal adenocarcinoma. In patients with a history of primary sclerosing cholangitis who present with nonspecific symptoms suggesting chronic gallbladder disease and radiologic evidence of circumferential gallbladder wall thickening containing intramural nodules and intact mucosa, xanthogranulomatous cholecystitis should be kept in mind.

Imaging of Hepatobiliary Cancer

The liver and biliary tree are common sites of primary and secondary malignancies. MRI followed by CT is the mainstay for the imaging characterization of these malignancies with the dynamically acquired contrast enhanced phases being the most important for diagnosis. The liver imaging reporting and data system classification provides a useful framework for reporting lesions in patents with underlying cirrhosis or who are at high risk for developing hepatocellular carcinoma. Detection of metastases is improved with the use of liver specific MRI contrast agents and diffusion weighted sequences. Aside from hepatocellular carcinoma, which is often diagnosed noninvasively, other primary hepatobiliary tumors may require biopsy for definite diagnosis, especially when presenting with nonclassic imaging findings. In this review, we examine the imaging findings of common and less common hepatobiliary tumors.

RadFormer: Transformers with global-local attention for interpretable and accurate Gallbladder Cancer detection

We propose a novel deep neural network architecture to learn interpretable representation for medical image analysis. Our architecture generates a global attention for region of interest, and then learns bag of words style deep feature embeddings with local attention. The global, and local feature maps are combined using a contemporary transformer architecture for highly accurate Gallbladder Cancer (GBC) detection from Ultrasound (USG) images. Our experiments indicate that the detection accuracy of our model beats even human radiologists, and advocates its use as the second reader for GBC diagnosis. Bag of words embeddings allow our model to be probed for generating interpretable explanations for GBC detection consistent with the ones reported in medical literature. We show that the proposed model not only helps understand decisions of neural network models but also aids in discovery of new visual features relevant to the diagnosis of GBC. Source-code is available at https://github.com/sbasu276/RadFormer.

What's new in the hot gallbladder: the evolving radiologic diagnosis and management of acute cholecystitis

Acute cholecystitis (AC) is a common condition and its incidence is rising. New technologies have advanced the imaging diagnosis of AC, providing more structural and functional information as well as allowing the radiologist to distinguish AC from mimics and identify complications from both the disease and its management. Dual energy CT aids in detecting gallstones and gallbladder wall enhancement, which helps to diagnose AC and identify its complications. Similarly, contrast-enhanced and non-contrast perfusion ultrasound techniques improve detection of abnormal gallbladder wall enhancement. Advances in MR imaging including hepatobiliary contrast agents aid in characterizing post-cholecystectomy complications such as bile leaks. Newer interventional techniques have also expanded the suite of options for minimally invasive management. Lumen apposing metal stents provide more options for conservative treatment in non-surgical candidates and are compared to a standard percutaneous cholecystostomy. Radiologists should be familiar with these advanced imaging methods and intervention techniques and the value they can bring to the diagnosis and management of AC.

Precordial pain caused by a hemocholecyst due to gallbladder cancer: A case report

INTRODUCTION AND IMPORTANCE

A hemocholecyst refers to hemorrhage originating from and confined to the gallbladder. Intraluminal hemorrhage of the gallbladder is a rare symptom of gallbladder cancer (GBC), which can cause hemorrhagic cholecystitis. The symptoms of hemorrhagic cholecystitis are similar to those of classic acute cholecystitis where precordial pain is atypical. Here, we report a case of a precordial pain-inducing hemocholecyst due to GBC.

CASE PRESENTATION

An 86-year-old woman was admitted to the emergency department due to persistent, sudden-onset precordial pain. Electrocardiogram (ECG) findings and cardiac enzyme levels were normal; however, severe anemia (hemoglobin 6.4 g/dL) was noted. Computed tomography (CT) showed a tense gallbladder with a heterogeneous, high-density area. Contrast-enhanced CT did not reveal contrast extravasation or obvious mass lesions. Considering the risk of hemorrhagic cholecystitis, we performed laparoscopic cholecystectomy. Operative findings were normal, however, the gallbladder lumen was filled with blood clots, while the gallbladder body had a papillary, infiltrating-type lesion.

CLINICAL DISCUSSION

Histopathological examination confirmed the diagnosis of moderately differentiated gallbladder adenocarcinoma. The precordial pain disappeared postoperatively. Due to the patient's age and general condition, no additional gallbladder bed resection or S4/5 hepatic bisegmentectomy and lymphadenectomy were performed.

CONCLUSION

A hemocholecyst can cause precordial pain; therefore, abdominal imaging may be useful for diagnosing patients with nonspecific precordial pain. In addition, GBC should be considered as a potential cause of hemocholecysts. Early diagnosis and urgent cholecystectomy should be performed to prevent gallbladder perforation in patients with hemocholecysts.

Robotic versus open extended cholecystectomy for T1a–T3 gallbladder cancer: A matched comparison

Background

The feasibility and safety of robotic extended cholecystectomy (REC) are still uncertain. This study was performed to compare the short- and long-term outcomes of REC with those of open extended cholecystectomy (OEC) for T1a–T3 gallbladder cancer.

Methods

From January 2015 to April 2022, 28 patients underwent REC in our center. To minimize any confounding factors, a 1:2 propensity score-matching analysis was conducted based on the patients’ demographics, liver function indicators, T stage, and symptoms. The data regarding demographics, perioperative outcomes, and long-term oncologic outcomes were reviewed.

Results

The visual analogue scale score was significantly lower in the REC than OEC group immediately postoperatively (3.68 ± 2.09 vs. 4.73 ± 1.85, P = 0.008), on postoperative day 1 (2.96 ± 1.75 vs. 3.69 ± 1.41, P = 0.023), and on postoperative day 2 (2.36 ± 1.55 vs. 2.92 ± 1.21, P = 0.031). In addition, the REC group exhibited a shorter time to first ambulation (P = 0.043), a shorter time to drainage tube removal (P = 0.038), and a shorter postoperative stay (P = 0.037), but hospital costs were significantly higher in the REC group (P &lt; 0.001). However, no statistically significant difference was found in the operation time (P = 0.134), intraoperative blood loss (P = 0.467), or incidence of postoperative morbidity (P = 0.227) or mortality (P = 0.289) between the REC and OEC groups. In regard to long-term outcomes, the 3-year disease-free survival rate was comparable between the OEC and REC groups (43.1% vs. 57.2%, P = 0.684), as was the 3-year overall survival rate (62.8% vs. 75.0%, P = 0.619).

Conclusion

REC can be an effective and safe alternative to OEC for selected patients with T1a–T3 gallbladder cancer with respect to short- and long-term outcomes.

Layered Double Hydroxide-Based Micro "Chemical Factory" with Arsenic Processing and Screening Functions on Nitinol for Gallbladder Cancer Treatment

Gallbladder cancer is a common malignant tumor of the biliary system with a high fatality rate. Nitinol (Ni-Ti) stents, a standard treatment for prolonging patients' lives, are susceptible to reocclusion and cannot inhibit tumor recurrence because they lack antitumor and antibacterial activity. Herein, an arsenic-loaded layered double-hydroxide film is constructed on Ni-Ti, forming a micro "chemical factory." The LDH plays the role of a "processer" which absorbs highly toxic trivalent arsenic (As(III)) and processes it into lowly toxic pentavalent arsenic (As(V)). It also acts as a "quality-inspector," confining As(III) in the interlayer and releasing only As(V) (the finished product) to the outside. This control mechanism minimizes the toxicity during contact with normal tissue. The acidic microenvironment and overexpression of glutathione in tumor tissues not only accelerates the release of arsenic from the platform but also triggers the in situ transformation of arsenic from lowly toxic As(V) to highly toxic As(III), exerting a strong arsenic-mediated antineoplastic effect. Such a microenvironment-responsive "chemical factory" with arsenic processing and screening functions is expected to prevent tumor overgrowth, metastasis, and bacterial infection and provide new insights into the design of Ni-Ti drug-eluting stents for gallbladder cancer treatment.

Multimodality Imaging of Cholecystectomy Complications

Cholecystectomy is one of the most common surgeries performed in the United States. Although complications are uncommon, the high incidence of this surgery means that a radiologist will likely encounter these complications in practice. Complications may arise in the immediate postoperative period or can be delayed for weeks, months, or years after surgery. Vague and nonspecific symptoms make clinical diagnosis challenging. As a result, multimodality imaging is important in postoperative evaluation. US and multidetector CT are the usual first-line imaging modalities. Hepatobiliary scintigraphy, SPECT/CT, and MRI with conventional or gadoxetate hepatobiliary contrast material are important and complementary modalities that are used for workup. The authors begin with a brief discussion of surgical technique and expected postoperative findings and then describe complications organized into four groups: (a) biliary complications, (b) stone-related complications, (c) iatrogenic complications, and (d) gallbladder complications. Biliary complications include bile leaks and bilomas, acute biliary obstruction, and biliary stricture. Stone-related complications include retained and recurrent stones and spillage of stones into the peritoneum. Iatrogenic complications include hemorrhage, vasculobiliary injury, arterial pseudoaneurysms, duodenal injury, and migration of clips. Gallbladder complications include recurrent cholecystitis after subtotal reconstituting cholecystectomy and unexpected gallbladder cancer. An invited commentary by Mullens and Ibrahim is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Antigallbladder Carcinoma Activity Analysis of a New Nanometer Drug Delivery System Based on Data Acquisition

In order to solve the problem of the application of data acquisition in the new nanometer drug delivery system of microscope, a research of antigallbladder carcinoma activity analysis was proposed. Gallbladder carcinoma (GBC) is a common malignant tumor in biliary tract diseases. Due to the lack of specific clinical manifestations in the early stage, GBC has the shortcomings of the hidden onset, the difficult diagnosis, and the high misdiagnosis rate. GBC ranks in the top position among the most common tumors of the digestive system worldwide. The preoperative diagnosis rate is low, and the incidence of accidental gallbladder carcinoma is gradually increasing. Domestic gallbladder carcinoma related to cholecystectomy is not sensitive to radiotherapy and chemotherapy. Surgical resection is still the only effective method for the treatment of accidental gallbladder carcinoma.

Preoperative Assessment and Perioperative Management of Resectable Gallbladder Cancer in the Era of Precision Medicine and Novel Technologies: State of the Art and Future Perspectives

Gallbladder carcinoma (GBC) is a rare malignancy, with an estimated 5-year survival rate of less than 5% in the case of advanced disease. Surgery is the only radical treatment for early stages, but its application and effectiveness depend on the depth of tumoral invasion. The extent of resection is usually determined according to the T-stage. Therefore, an early and correct preoperative assessment is important for the prognosis, as well as for the selection of the most appropriate surgical procedure, to avoid unnecessary morbid surgeries and to reach the best outcomes. Several modalities can be used to investigate the depth of invasion, from ultrasounds to CT scans and MRI, but an ideal method still does not exist. Thus, different protocols are proposed according to different recommendations and institutions. In this scenario, the indications for laparoscopic and robotic surgery are still debated, as well as the role of new technologies such as next-generation sequencing and liquid biopsies. The aim of this article is to summarize the state of the art current modalities and future perspectives for assessing the depth of invasion in GBC and to clarify their role in perioperative management accordingly.

Abdominal and pelvic splenosis: atypical findings, pitfalls, and mimics

Splenosis is an acquired form of ectopic splenic tissue that typically arises after trauma or splenectomy. It is often an incidental image finding in an otherwise asymptomatic patient, but the spectrum of symptoms varies based on the site of implantation. Radiologists should be familiar with the imaging features of splenosis to avoid mistaking it for malignancy. Splenosis has identical imaging features to that of the native spleen on US, CT, MRI, and nuclear medicine examinations. Therefore, when the radiologic findings support the diagnosis of splenosis, the patient can be spared invasive procedures for tissue sampling.

Gallbladder reporting and data system (GB-RADS) for risk stratification of gallbladder wall thickening on ultrasonography: an international expert consensus

The Gallbladder Reporting and Data System (GB-RADS) ultrasound (US) risk stratification is proposed to improve consistency in US interpretations, reporting, and assessment of risk of malignancy in gallbladder wall thickening in non-acute setting. It was developed based on a systematic review of the literature and the consensus of an international multidisciplinary committee comprising expert radiologists, gastroenterologists, gastrointestinal surgeons, surgical oncologists, medical oncologists, and pathologists using modified Delphi method. For risk stratification, the GB-RADS system recommends six categories (GB-RADS 0-5) of gallbladder wall thickening with gradually increasing risk of malignancy. GB-RADS is based on gallbladder wall features on US including symmetry and extent (focal vs. circumferential) of involvement, layered appearance, intramural features (including intramural cysts and echogenic foci), and interface with the liver. GB-RADS represents the first collaborative effort at risk stratifying the gallbladder wall thickening. This concept is in line with the other US-based risk stratification systems which have been shown to increase the accuracy of detection of malignant lesions and improve management.

Magnetic Fields and Cancer: Epidemiology, Cellular Biology, and Theranostics

Humans are exposed to a complex mix of man-made electric and magnetic fields (MFs) at many different frequencies, at home and at work. Epidemiological studies indicate that there is a positive relationship between residential/domestic and occupational exposure to extremely low frequency electromagnetic fields and some types of cancer, although some other studies indicate no relationship. In this review, after an introduction on the MF definition and a description of natural/anthropogenic sources, the epidemiology of residential/domestic and occupational exposure to MFs and cancer is reviewed, with reference to leukemia, brain, and breast cancer. The in vivo and in vitro effects of MFs on cancer are reviewed considering both human and animal cells, with particular reference to the involvement of reactive oxygen species (ROS). MF application on cancer diagnostic and therapy (theranostic) are also reviewed by describing the use of different magnetic resonance imaging (MRI) applications for the detection of several cancers. Finally, the use of magnetic nanoparticles is described in terms of treatment of cancer by nanomedical applications for the precise delivery of anticancer drugs, nanosurgery by magnetomechanic methods, and selective killing of cancer cells by magnetic hyperthermia. The supplementary tables provide quantitative data and methodologies in epidemiological and cell biology studies. Although scientists do not generally agree that there is a cause-effect relationship between exposure to MF and cancer, MFs might not be the direct cause of cancer but may contribute to produce ROS and generate oxidative stress, which could trigger or enhance the expression of oncogenes.

Grayscale ultrasonography findings for characterization of gallbladder wall thickening in non-acute setting: a systematic review and meta-analysis

BACKGROUND

The accurate characterization of gallbladder wall thickening (GWT) into benign or malignant on ultrasound (US) is a significant challenge.

METHODS

We searched the MEDLINE and EMBASE databases for studies reporting two-dimensional grayscale US in benign and malignant GWT. The pooled prevalence was calculated using a generalized linear mixed method with a random-effects model. The pooled sensitivity and specificity were calculated using a bivariate random-effects model.

RESULTS

Of the 7309 studies screened by titles, 73 studies with 18,008 patients were included. The most common findings in xanthogranulomatous cholecystitis (XGC) were lack of wall disruption and intramural hypoechoic nodules while adenomyomatosis (ADM) was frequently associated with intramural cysts and intramural echogenic foci. Echogenic foci, lack of gallbladder wall disruption, and hypoechoic nodules had a sensitivity of 89%, 77%, and 66% and specificity of 86%, 51%, and 80%, respectively for the diagnosis of benign GWT. Focal thickening and indistinct liver interface had a sensitivity of 75% and 55% and specificity of 64% and 69%, respectively for the diagnosis of malignant GWT.

CONCLUSION

intramural features (echogenic foci, hypoechoic nodules), gallbladder wall disruption, and liver interface are useful US features for the characterization of GWT.

Temporal evolution of metastatic disease: part I-an in-depth review of the evolution of metastatic disease across diverse spectrum of non-neural solid tumors on serial oncologic imaging studies and relevant practical applications

With improved survival rates of patients with metastatic disease due to continuously evolving multimodality treatment options, radiologists are increasingly interpreting imaging studies from patients with protracted metastatic disease. It is thus crucial for radiologists to have an in-depth understanding of the temporal evolution of metastatic spread and the accompanying findings on imaging studies, to provide accurate interpretation that supports optimal management. A general overview of the evolution of cancer spread on serial imaging studies and common pathways of tumor spread across multiple tumor types and tumor locations is not readily available in radiology literature. The key common pathways of tumor spread across diverse spectrum of tumors relevant to radiologists are summarized in a logical schematic approach which focusses on aiding radiologists to understand the pathways of spread resulting in current sites of metastatic disease involvement and then to potentially predict future sites of metastatic involvement. This article also summarizes the practical applications of this knowledge to the routine oncologic imaging interpretation.