Cross-sectional imaging of gastric neoplasia. Clin Radiol. 2009;64:420-429. [PMID: 19264188 DOI: 10.1016/j.crad.2008.09.012]

Diagnostic Endoscopic Ultrasound (EUS) of the Luminal Gastrointestinal Tract

The purpose of this review is to focus on the diagnostic endoscopic ultrasound of the gastrointestinal tract. In the last decades, EUS has gained a central role in the staging of epithelial and sub-epithelial lesions of the gastrointestinal tract. With the evolution of imaging, the position of EUS in the diagnostic work-up and the staging flow-chart has continuously changed with two extreme positions: some gastroenterologists think that EUS is absolutely indispensable, and some think it is utterly useless. The truth is, as always, somewhere in between the two extremes. Analyzing the most up-to-date and strong evidence, we will try to give EUS the correct position in our daily practice.

Implementation of cinematic rendering of gastric masses into clinical practice: a pictorial review

High-resolution CT is the gold standard diagnostic imaging study for staging of gastric malignancies. Cinematic rendering creates a photorealistic evaluation using the standard high-resolution CT volumetric data set. This novel display method offers unique possibilities for the evaluation of gastric masses. Here we present further observations of the role of cinematic rendering in the evaluation of gastric masses at a large tertiary care center. We offer three valuable teaching points for the application of the cinematic rendering for gastric masses with several case examples for each teaching point, discuss potential limitations of cinematic rendering, and review future directions for cinematic rendering in this setting.

CT features of confirmed and presumed gastric wall edema in dogs

Postcontrast computed tomographic (CT) characteristics of gastrointestinal (GI) wall edema in humans have been described as GI wall thickening with a thickened submucosal layer and thin enhanced inner and outer layers. Published studies describing CT features of gastric wall edema in dogs are currently lacking. The aim of this retrospective, case series was to describe CT features of gastric wall edema in a group of dogs. Medical records were searched for dogs with postcontrast abdominal CT scans and a diagnosis of gastric wall edema based on histopathology (group I) or CT characteristics consistent with those reported in humans (group II). Clinical diagnosis, mean serum albumin concentration, and histopathological diagnosis were recorded. The following CT characteristics were recorded: numbers of wall layers, attenuation and contrast enhancement, presence of blood vessels, locations, distribution, and thickness. Twelve dogs (3 in group I and 9 in group II) were included. The most common clinical finding was hypoalbuminemia. In group I, a well-defined three-layer appearance with a non-enhancing fluid-attenuating middle layer was observed in three dogs and thin blood vessels in the middle layer in two dogs. In group II, nine dogs had a three-layer appearance with a non-enhancing fluid-attenuating middle layer. Locations of gastric wall thickening were diffuse in two, focal concentric in six, and focal asymmetric in four dogs. Findings supported including gastric wall edema as a differential diagnosis for dogs with hypoalbuminemia and CT characteristics of a three-layer appearance in the gastric wall, with a non-enhancing fluid-attenuating middle layer and thin blood vessels.

Imaging of Gastric Carcinoma. Part One: Diagnosis and Staging

Gastric cancer is one of the leading causes of death from malignancy. Despite the enormous advancement in medical oncology over the past decade, surgical resection of early tumors remains the most effective treatment. Accurate interpretation of radiologic imaging studies is crucial for staging local disease spread, predicting possible lymphatic involvement, and identifying metastatic disease, thereby guiding management plans. This article reviews imaging patterns of the normal stomach along with appearances of gastric cancer, its local spread patterns and distant metastasis, and also describes key features pertaining to preoperative staging.

Imaging of Neuroendocrine Tumors: Indications, Interpretations, Limits, and Pitfalls

Imaging is critical in the diagnosis, prognosis, and management of neuroendocrine tumors (NETs). NETs share common imaging features, but each type exhibits unique features. Computed tomography scans or MRI of the abdomen is used to assess tumor burden routinely. Functional imaging with octreotide scan or gallium-68 somatostatin analog PET is used selectively to confirm diagnosis and guide therapy. Clinicians and radiologists should be familiar with the indications and interpretations of imaging modalities. Novel functional imaging modalities likely will be developed to detect small NETs, predict prognosis, guide therapeutic choices, and design novel therapies.

Endoscopic ultrasound in oncology: An update of clinical applications in the gastrointestinal tract

An accurate staging is necessary to select the best treatment and evaluate prognosis in oncology. Staging usually begins with noninvasive imaging such as computed tomography, magnetic resonance imaging or positron emission tomography. In the absence of distant metastases, endoscopic ultrasound plays an important role in the diagnosis and staging of gastrointestinal tumors, being the most accurate modality for local-regional staging. Its use for tumor and nodal involvement in pre-surgical evaluation has proven to reduce unnecessary surgeries. The aim of this article is to review the current role of endoscopic ultrasound in the diagnosis and staging of esophageal, gastric and colorectal cancer.

Diagnostic accuracy of endoscopic ultrasonography (EUS) for the preoperative locoregional staging of primary gastric cancer

BACKGROUND

Endoscopic ultrasound (EUS) is proposed as an accurate diagnostic device for the locoregional staging of gastric cancer, which is crucial to developing a correct therapeutic strategy and ultimately to providing patients with the best chance of cure. However, despite a number of studies addressing this issue, there is no consensus on the role of EUS in routine clinical practice.

OBJECTIVES

To provide both a comprehensive overview and a quantitative analysis of the published data regarding the ability of EUS to preoperatively define the locoregional disease spread (i.e., primary tumor depth (T-stage) and regional lymph node status (N-stage)) in people with primary gastric carcinoma.

SEARCH METHODS

We performed a systematic search to identify articles that examined the diagnostic accuracy of EUS (the index test) in the evaluation of primary gastric cancer depth of invasion (T-stage, according to the AJCC/UICC TNM staging system categories T1, T2, T3 and T4) and regional lymph node status (N-stage, disease-free (N0) versus metastatic (N+)) using histopathology as the reference standard. To this end, we searched the following databases: the Cochrane Library (the Cochrane Central Register of Controlled Trials (CENTRAL)), MEDLINE, EMBASE, NIHR Prospero Register, MEDION, Aggressive Research Intelligence Facility (ARIF), ClinicalTrials.gov, Current Controlled Trials MetaRegister, and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), from 1988 to January 2015.

SELECTION CRITERIA

We included studies that met the following main inclusion criteria: 1) a minimum sample size of 10 patients with histologically-proven primary carcinoma of the stomach (target condition); 2) comparison of EUS (index test) with pathology evaluation (reference standard) in terms of primary tumor (T-stage) and regional lymph nodes (N-stage). We excluded reports with possible overlap with the selected studies.

DATA COLLECTION AND ANALYSIS

For each study, two review authors extracted a standard set of data, using a dedicated data extraction form. We assessed data quality using a standard procedure according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. We performed diagnostic accuracy meta-analysis using the hierarchical bivariate method.

MAIN RESULTS

We identified 66 articles (published between 1988 and 2012) that were eligible according to the inclusion criteria. We collected the data on 7747 patients with gastric cancer who were staged with EUS. Overall the quality of the included studies was good: in particular, only five studies presented a high risk of index test interpretation bias and two studies presented a high risk of selection bias.For primary tumor (T) stage, results were stratified according to the depth of invasion of the gastric wall. The meta-analysis of 50 studies (n = 4397) showed that the summary sensitivity and specificity of EUS in discriminating T1 to T2 (superficial) versus T3 to T4 (advanced) gastric carcinomas were 0.86 (95% confidence interval (CI) 0.81 to 0.90) and 0.90 (95% CI 0.87 to 0.93) respectively. For the diagnostic capacity of EUS to distinguish T1 (early gastric cancer, EGC) versus T2 (muscle-infiltrating) tumors, the meta-analysis of 46 studies (n = 2742) showed that the summary sensitivity and specificity were 0.85 (95% CI 0.78 to 0.91) and 0.90 (95% CI 0.85 to 0.93) respectively. When we addressed the capacity of EUS to distinguish between T1a (mucosal) versus T1b (submucosal) cancers the meta-analysis of 20 studies (n = 3321) showed that the summary sensitivity and specificity were 0.87 (95% CI 0.81 to 0.92) and 0.75 (95% CI 0.62 to 0.84) respectively. Finally, for the metastatic involvement of lymph nodes (N-stage), the meta-analysis of 44 studies (n = 3573) showed that the summary sensitivity and specificity were 0.83 (95% CI 0.79 to 0.87) and 0.67 (95% CI 0.61 to 0.72), respectively.Overall, as demonstrated also by the Bayesian nomograms, which enable readers to calculate post-test probabilities for any target condition prevalence, the EUS accuracy can be considered clinically useful to guide physicians in the locoregional staging of people with gastric cancer. However, it should be noted that between-study heterogeneity was not negligible: unfortunately, we could not identify any consistent source of the observed heterogeneity. Therefore, all accuracy measures reported in the present work and summarizing the available evidence should be interpreted cautiously. Moreover, we must emphasize that the analysis of positive and negative likelihood values revealed that EUS diagnostic performance cannot be considered optimal either for disease confirmation or for exclusion, especially for the ability of EUS to distinguish T1a (mucosal) versus T1b (submucosal) cancers and positive versus negative lymph node status.

AUTHORS' CONCLUSIONS

By analyzing the data from the largest series ever considered, we found that the diagnostic accuracy of EUS might be considered clinically useful to guide physicians in the locoregional staging of people with gastric carcinoma. However, the heterogeneity of the results warrants special caution, as well as further investigation for the identification of factors influencing the outcome of this diagnostic tool. Moreover, physicians should be warned that EUS performance is lower in diagnosing superficial tumors (T1a versus T1b) and lymph node status (positive versus negative). Overall, we observed large heterogeneity and its source needs to be understood before any definitive conclusion can be drawn about the use of EUS can be proposed in routine clinical settings.

Gastric large cell neuroendocrine carcinoma with venous tumor thrombus: the value of PET/CT and contrast-enhanced computed tomography

Venous involvement is commonly detected microscopically on gastric neuroendocrine carcinomas (NECs), but related imaging studies have been rarely documented. We report a rare case of gastric large cell NEC with tumor thrombi in gastric and splenic veins, elevated serum alpha fetoprotein, and multiple hepatic nodules. In this case, (18)F-fluorodeoxyglucose positron emission tomography combined with contrast-enhanced computed tomography provided valuable information on tumor staging.

Is endoscopic ultrasonography still the modality of choice in preoperative staging of gastric cancer?

The treatment option for gastric cancer is usually based on preoperative staging by imaging modalities. Endoscopic ultrasonography (EUS) and computed tomography (CT) have been used as the diagnostic modality of choice in preoperative staging of gastric cancer. Magnetic resonance imaging (MRI) has been employed in several studies, and (¹⁸F) 2-Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has emerged as a new promising imaging modality. The purpose of this article is to provide summarized information on preoperative staging using EUS, multi-detector row CT (MDCT), MRI and PET for gastric cancer. In T staging, both EUS and MDCT show high accuracy. MRI seemed to have better performance, but the number of MRI studies is limited. FDG-PET is not able to properly evaluate the depth of invasion. In N staging, the diagnostic accuracy of EUS, MDCT and MRI is not sufficient. In preoperative M staging, MDCT and FDG-PET showed similar diagnostic accuracies. FDG-PET/CT fusion could be expected to show better performance in the future. Physicians should keep in mind that each diagnostic modality has advantages and limitations and choose an appropriate diagnostic strategy tailored for each patient.

The extent of lymph node dissection for gastric cancer: a critical appraisal

The extent of lymphadenectomy during therapeutic gastrectomy for gastric cancer remains a protracted and controversial issue. While traditionally extended lymphadenectomy is performed in Eastern Asia, limited lymphadenectomy is advocated by most western surgeons. Two large western randomized trials, meta-analyses and a recent systematic review were unable to demonstrate overall benefit from extended lymphadenectomy. In this review, the currently available data on this topic are critically evaluated, while ongoing studies and future perspective are discussed.

Diagnosis and staging in gastrointestinal lymphoma

The diagnosis gastrointestinal lymphoma can be made on endoscopic biopsies in the vast majority of cases. Definitive subtyping of the lymphoma according to the WHO classification with the use of additional immunological and molecular markers is the cornerstone for further decision making. Several lymphomas may occur multifocally or show both small cell and large cell components. Therefore, a second endoscopy with an extensive biopsy protocol (mapping) may be mandatory. Staging procedures are required for therapeutic decision making and should include CT-scan, laboratory studies and bone marrow examination as required in other lymphomas. Additional studies must be performed depending subtype and localisation of the lymphoma. In gastric lymphoma endosonography reveals prognostic information. In marginal zone lymphoma of MALT-type attention to other MALT-sites and autoimmune diseases is necessary. In enteropathy-associated T-cell lymphoma screening for coeliac disease and enteroscopy are required. In several lymphomas (diffuse large B-cell lymphoma and mantle cell lymphoma) a PET-scan is considered as standard of care. The value of staging procedures after treatment is less well defined. At least in gastric lymphomas, histology is the gold standard after treatment and during follow-up.

Advances in imaging diagnosis of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST) are the most common non-epithelial tumors. In recent years, the development of imaging technology has resulted in an increase in diagnostic yield of GIST. In this article, we will review the recent advances in imaging diagnosis of GIST.