MDCT imaging of the stomach: advances and applications

Assessing Residual Gastric Fluid Volume after Administering Diluted Oral Contrast until One Hour Prior to Anesthesia in Children: An Observational Cohort Study

Background: Gastric fluid volume has been used as a surrogate marker for pulmonary aspiration risk in studies evaluating fasting protocol safety. This study measured residual gastric fluid volume in children using a protocol in which diluted oral contrast medium was administered up until one hour before anesthesia. Methods: This was a single-center prospective observational cohort trial of 70 children for elective abdominal/pelvic computed tomography (CT). Imaging was performed after diluted enteral contrast medium administration, beginning two hours before and ending at least one hour before induction. For each patient, gastric fluid volume was calculated using an image region of interest. The primary outcome measure was gastric fluid volume measured using the computed tomography image. Results: The median time from the end of contrast administration to imaging was 1.5 h (range: 1.1 to 2.2 h). Residual gastric volume, measured using CT was <0.4 mL/Kg in 33%; ≥0.4 mL/Kg in 67%; and ≥1.5 mL/Kg in 44% of patients. Residual gastric volumes measured using CT and aspiration were moderately correlated (Spearman's correlation coefficient = 0.41, p = 0.0003). However, the median residual gastric volume measured using CT (1.17, IQR: 0.22 to 2.38 mL/Kg) was higher than that of aspiration (0.51, IQR: 0 to 1.58 mL/Kg, p = 0.0008 on differences in paired measures). Three cases of vomiting were reported. No evidence of pulmonary aspiration was identified. Conclusions: Children who receive large quantities of clear fluid up to one hour before anesthesia can have a significant gastric residual volume.

Imaging Features of Gastrointestinal Neoplasms Complicating Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory diseases affecting the gastrointestinal (GI) tract. Patients with IBD, besides other non-neoplastic complications, are also at increased risk of GI malignancies such as colorectal cancer, small bowel adenocarcinoma and lymphoma. The principal purpose of imaging in patients with IBD to assess complications and to stage a clinically known cancer. In addition, the goal of imaging has expanded to include the diagnosis of GI malignancies in clinical situations where colonoscopy cannot be performed or is incomplete. In addition, imaging allows the detection of cancers in patients where the development of either disease-related or treatment-related neoplasia is clinically suspected. The purpose of this review is to present the different imaging techniques used to detect GI malignancies in IBD patients and describe the radiological appearances of GI malignancies in IBD patients.

The incremental value of multislice CT in diagnosis of late bariatric surgery complications

Background

Bariatric surgery has become a widely accepted treatment option among the population for obesity management. Nevertheless, different complications may still be encountered during the late post-operative period. Our prospective cross-sectional study aimed to show the incremental value of multislice CT for diagnosis of such complications.

Results

Within the included twenty patients who underwent multislice CT of upper abdomen, gastric pouch dilatation causing recurrent weight gain was the commonest complication detected in 70% of the studied patients and was found mainly after sleeve gastrectomy in whom mean gastric pouch volume was 248.4 ml. Gastric stricture, gastric herniation through plication suture, hiatus hernia and incisional hernia were less commonly encountered complications.

Conclusion

Multislice CT is a useful non-invasive imaging modality for detection of late bariatric surgery complications.

Mesenchymal tumors of the stomach: radiologic and pathologic correlation

Mesenchymal tumors of the stomach are uncommon, with gastrointestinal stromal tumor (GIST) being the most common among them. Majority of the tumors may arise from cells of Cajal, smooth muscle cells, neural cells, totipotent stem cells, adipocytes or fibroblasts. Imaging plays an important role not only in staging but also in characterizing these tumors. Many of these tumors have characteristic imaging features. GISTs usually present as large cavitating and necrotic tumors with exophytic component. Presence of fat tissue within the tumor suggests a lipoma or a teratoma, early phase hyperenhancement indicates glomus tumor and hemangioma, and delayed contrast enhancement is seen in schwannoma. Their differentiation from epithelial tumors like carcinoma and neuroendocrine tumors is often possible based on the location (mesenchymal tumors are intramural), spread, morphological appearance and enhancement patterns. However, overlapping features exist between these tumors with imaging often being only suggestive. A biopsy is necessary for a definitive diagnosis in many cases.

Correlation between pneumo-computed tomography and pathology findings for subepithelial gastric lesions

OBJECTIVE

This article aims to show the usefulness of the pneumo-computed tomography gastric distention technique in the detection and morphological characterization of subepithelial gastric lesions. We correlate the pneumo-computed tomography and pathology findings in lesions studied at our institution and review the relevant literature.

CONCLUSION

Pneumo-computed tomography, combined with multiplanar reconstructions, three-dimensional reconstructions, and virtual endoscopy, is useful for delineating the morphological details of subepithelial gastric lesions, thanks to the additional gastric distention. This technique better delimits and characterizes the upper and lower margins of the lesions. Pneumo-computed tomography can be considered a useful noninvasive imaging techniques for characterizing these lesions.

A Heterogeneity Radiomic Nomogram for Preoperative Differentiation of Primary Gastric Lymphoma From Borrmann Type IV Gastric Cancer

OBJECTIVE

This study aimed to preoperatively differentiate primary gastric lymphoma from Borrmann type IV gastric cancer by heterogeneity nomogram based on routine contrast-enhanced computed tomographic images.

METHODS

We enrolled 189 patients from 2 hospitals (90 in the training cohort and 99 in the validation cohort). Subjective findings, including high-enhanced mucosal sign, high-enhanced serosa sign, nodular or an irregular outer layer of the gastric wall, and perigastric fat infiltration, were assessed to construct a subjective finding model. A deep learning model was developed to segment tumor areas, from which 1680 three-dimensional heterogeneity radiomic parameters, including first-order entropy, second-order entropy, and texture complexity, were extracted to build a heterogeneity signature by least absolute shrinkage and selection operator logistic regression. A nomogram that integrates heterogeneity signature and subjective findings was developed by multivariate logistic regression. The diagnostic performance of the nomogram was assessed by discrimination and clinical usefulness.

RESULTS

High-enhanced serosa sign and nodular or an irregular outer layer of the gastric wall were identified as independent predictors for building the subjective finding model. High-enhanced serosa sign and heterogeneity signature were significant predictors for differentiating the 2 groups (all, P < 0.05). The area under the curve with heterogeneity nomogram was 0.932 (95% confidence interval, 0.863-0.973) in the validation cohort. Decision curve analysis and stratified analysis confirmed the clinical utility of the heterogeneity nomogram.

CONCLUSIONS

The proposed heterogeneity radiomic nomogram on contrast-enhanced computed tomographic images may help differentiate primary gastric lymphoma from Borrmann type IV gastric cancer preoperatively.

Gastric Outlet Obstruction in the Current Era–A Pictorial Review on Computed Tomography Imaging

Gastric outlet obstruction is a pathophysiological entity characterized by mechanical impediment of gastric emptying, which may occur due to a variety of intrinsic or extrinsic causes affecting the antrum or pylorus or duodenum. The obstruction may be benign or malignant or secondary to a motility disorder. Imaging in gastric outlet obstruction identifies majority of these causes and may indirectly even point toward motility disorders. The advent of computed tomography imaging and its subsequent advances have allowed it to become the mainstay of evaluation of stomach, particularly in gastric outlet obstruction. In this pictorial review, a few causes of gastric outlet obstruction are exhibited.

Intra-mural distribution of the blood vessels in the stomach demonstrated by contrast medium injection: a cadaver study

PURPOSE

With advances in diagnostic imaging techniques of gastric cancer screening with X-ray fluoroscopy, it has been suggested that mucosal projections induced by the vessels distributed in the submucosal layer of the stomach may be mistaken for abnormal mucosal folds. In this study, we aimed to describe the distribution of blood vessels in the submucosal layer of the stomach to improve the diagnostic accuracy of screening of gastric cancer.

METHODS

Twenty-four stomachs from Japanese cadavers were used in this study. Uncolored or colored contrast agents were injected into arteries and/or veins for macroscopic analyses, X-ray imaging, and methyl salicylate clearing. In addition, histological analysis was performed to examine blood vessels distributed inside the stomach wall.

RESULTS

Following contrast agent injection, thick blood vessels were distributed perpendicular to both curvature sides, and branches parallel to both curvature sides flowed from these thick blood vessels, and a vascular network was formed throughout the stomach wall. This vascular network had intra-mural anastomoses connecting both curvature sides. Moreover, in histological analyses, blood vessels depicted by injection were mainly distributed in the submucosal layer.

CONCLUSION

This study strongly suggests that the mucosal projections induced by arteries and veins in the submucosal layer could be mistaken for abnormal mucosal folds. Therefore, a better understanding of the vascular distribution in the submucosal layer is important to improve diagnostic accuracy from imaging studies of the stomach. The information provided by this research may facilitate better accuracy in diagnosis and reduce the number of unnecessary invasive procedures.

Hemosuccus pancreatitis due to a ruptured splenic artery pseudoaneurysm - diagnosis and endovascular management

Hemosuccus pancreatitis is a rare and potentially fatal cause of upper gastrointestinal bleeding characterized by hemorrhage from the ampulla of Vater via the pancreatic duct. In this case, a patient with chronic pancreatitis on a background of chronic alcoholism is found to have a splenic artery pseudoaneurysm that was bleeding into the pancreatic duct. This was identified on contrast-enhanced computed tomography imaging and successfully managed via microcoil embolization.

Gastrointestinal Applications of Iodine Quantification Using Dual-Energy CT: A Systematic Review

Dual-energy computed tomography (DECT) can estimate tissue vascularity and perfusion via iodine quantification. The aim of this systematic review was to outline current and emerging clinical applications of iodine quantification within the gastrointestinal tract using DECT. The search was conducted with three databases: EMBASE, Pubmed and The Cochrane Library. This identified 449 studies after duplicate removal. From a total of 570 selected studies, 30 studies were enrolled for the systematic review. The studies were categorized into four main topics: gastric tumors (12 studies), colorectal tumors (8 studies), Crohn’s disease (4 studies) and miscellaneous applications (6 studies). Findings included a significant difference in iodine concentration (IC) measurements in perigastric fat between T1–3 vs. T4 stage gastric cancer, poorly and well differentiated gastric and colorectal cancer, responders vs. non-responders following chemo- or chemoradiotherapy treatment among cancer patients, and a positive correlation between IC and Crohn’s disease activity. In conclusion, iodine quantification with DECT may be used preoperatively in cancer imaging as well as for monitoring treatment response. Future studies are warranted to evaluate the capabilities and limitations of DECT in splanchnic flow.

Diagnostic accuracy of the gastric cancer T-category with respect to tumor localization

Purpose

Diagnosing early gastric cancer (EGC) or advanced gastric cancer (AGC) according to T-category is important for optimal GC treatment; however, the clinical and pathological diagnosis of tumor depths can sometimes vary. This study investigated the accuracy of clinical diagnosis of the tumor depth from the viewpoint of tumor localization and prognosis of patients with GC with discordance between clinical and pathological findings.

Methods

This study enrolled 741 patients with primary GC who underwent curative gastrectomy. Based on the clinical and pathological diagnosis of T-category, the patients were classified into four groups: Early-look EGC, Early-look AGC, Advanced-look EGC, and Advanced-look AGC. Tumor localization was classified longitudinally (the upper [U], middle [M], and lower [L] parts and cross-sectionally (the anterior [Ant] and posterior [Post] walls, and the lesser [Less] and greater [Gre] curvatures).

Results

Of the 462 clinical EGC cases, 52 were Early-look AGC cases that exhibited a significant association of tumor localization with the Post and Less in the U and M locations (UM-PL; p = 0.037). An Advanced-look EGC (p = 0.031) and Advanced-look AGC (p = 0.025) were independent prognostic factors for relapse-free survival each in pathological EGC and AGC, respectively.

Conclusions

Patients with clinically diagnosed EGC but with pathologically diagnosed AGC more frequently presented tumor in the UM-PL than in any other location. Selection of therapeutic strategy according to the clinical diagnosis might be critical; however, it should be also considered that the accuracy of preoperative assessments varies with tumor localization.

Electronic supplementary material

The online version of this article (10.1007/s00423-020-01971-3) contains supplementary material, which is available to authorized users.

Consensus statement of the Hellenic and Cypriot Gastric Cancer Study Group on the diagnosis, staging and management of gastric cancer

Gastric Cancer epidemics have changed over recent decades, declining in incidence, shifting from distal to proximal location, transforming from intestinal to diffuse histology. Novel chemotherapeutic agents combined with modern surgical operations hardly changed overall disease related survival. This may be attributed to a substantial inherent geographical variation of disease genetics, but also to a failure to standardize and implement treatment protocols in clinical practice. To overcome these drawbacks in Greece and Cyprus, a Gastric Cancer Study Group under the auspices of the Hellenic Society of Medical Oncology (HeSMO) and Gastrointestinal Cancer Study Group (GIC-SG) merged their efforts to produce a consensus considering ethnic parameters of healthcare system and the international proposals as well. Utilizing structured meetings of experts, a consensus was reached. To achieve further consensus, statements were subjected to the Delphi methodology by invited multidisciplinary national and international experts. Sentences were considered of high or low consensus if they were voted by ≥ 80%, or < 80%, respectively; those obtaining a low consensus level after both voting rounds were rejected. Forty-five statements were developed and voted by 71 experts. The median rate of abstention per statement was 9.9% (range: 0-53.5%). At the end of the process, one statement was rejected, another revised, and all the remaining achieved a high consensus. Forty-four recommendations covering all aspects of the management of gastric cancer and concise treatment algorithms are proposed by the Hellenic and Cypriot Gastric Cancer Study Group. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and individualization are emphasized.

Contrast-enhanced computed tomography may be helpful for characterizing and staging canine gastric tumors

In humans, computed tomography (CT) is a widely performed technique for the diagnosis and staging of gastric tumors. The purpose of this retrospective case series study was to describe CT findings in a group of dogs with confirmed gastric tumors. For each included dog, the following CT parameters were recorded: gastric tumor location, tumor shape, gastric involvement pattern, tumor enhancement pattern in early and late phases, presence and location of lymphadenopathy, gastric tumor attenuation values, attenuation values of enlarged lymph nodes, maximum short-axis diameter (mm) of enlarged lymph node, maximum long-axis diameter (mm) of enlarged lymph node, and short-axis diameter to long-axis diameter ratio (short axis/long axis). A total of 16 dogs met inclusion criteria and had the following final diagnoses: five lymphoma, six adenocarcinoma, three inflammatory polyps, and two leiomyoma. In the early- and delayed-phase postcontrast images, the mean CT attenuation value for lymphoma was lower than that of other gastric tumors. Lymphadenopathy was widespread in lymphomas and regional in adenocarcinomas. Lymphadenopathy was not detected in leiomyomas. Lymph node measurements in lymphoma were larger than lymph node measurements in adenocarcinoma. Although there were overlapping findings for the different types of gastric tumors, contrast-enhanced CT provided helpful information for characterizing gastric tumors based on the following criteria: early and late enhancement patterns, the site of origin of the mass lesion, and extent of local invasion and distant metastases. Lymphoma should be considered for canine gastric tumors with low mean attenuation values during early- and delayed-phase postcontrast images, and widespread, bulky, and rounded lymphadenopathy.