Sonographic assessments of gastrointestinal and biliary functions

Multivariate analysis of factors associated with the successful prediction of initial blind placement of a nasointestinal tube in the stomach based on X-ray imaging: a retrospective, single-center study

BACKGROUND

Patients in the intensive care unit (ICU) are highly susceptible to malnutrition, and while enteral nutrition via nasogastric tube is the preferred method, there is a risk of inadvertent reflux and aspiration. Therefore, clinicians have turned to nasointestinal tubes (NET) for enteral nutrition as an alternative option. But the precise localization of NET presents an ongoing challenge. We proposed an innovative approach to provide a valuable reference for clinicians involved in NET placement.

METHOD

Data were obtained retrospectively from the medical records of adult patients with a high risk of aspiration or gastric feeding intolerance who had a NET placed in the ICU of Zhejiang Provincial People's Hospital between October 1, 2017, and October 1, 2023. The collected data were subjected to statistical analysis using SPSS and R software.

RESULT

There were 494 patients who met the inclusion and exclusion criteria. The first-pass success rate was 81.4% (n = 402). The success of a patient's initial NET placement was found to be associated with Angle SPC and Distance CP, as determined by univariate analysis (25.6 ± 16.7° vs. 41.9 ± 18.0°, P < 0.001; 40.0 ± 26.2 mm vs. 62.0 ± 31.8 mm, P < 0.001, respectively). By conducting a multivariate regression analysis, we identified a significant association between pyloric types and the success rate of placing NET (OR 29.559, 95%CI 14.084-62.038, P < 0.001).

CONCLUSION

Angle SPC, Distance CP, and the type of pylorus are independently associated with successful initial placement of NET. Besides, patients with the outside type of pylorus (OP-type) exhibit a higher rate of initial placement success.

Recent advances in measuring the effects of diet on gastrointestinal physiology: Probing the "leaky gut" and application of real-time ultrasound

There is a large pool of ideas in both mainstream and non-mainstream medicine on how diet can be manipulated in order to treat or prevent illnesses. Despite this, our understanding of how specific changes in diet influence the structure and function of the gastrointestinal tract is limited. This review aims to describe two areas that might provide key information on the integrity and function of the gastrointestinal tract. First, demystifying the "leaky gut syndrome" requires rational application and interpretation of tests of intestinal barrier function. Multiple ways of measuring barrier function have been described, but the inherent difficulties in translation from animal studies to humans have created misinterpretations and misconceptions. The intrinsic nature of intestinal barrier function is dynamic. This is seldom considered in studies of intestinal barrier assessment. To adequately understand the effects of dietary interventions on intestinal barrier function, background barrier function in different regions of the gut and the dynamic responses to stressors (such as psychological stress) should be assessed as a minimum. Second, intestinal ultrasound, which is now established in the assessment and monitoring of inflammatory bowel disease, has hitherto been poorly evaluated in assessing real-time intestinal function and novel aspects of structure in patients with disorders of gut-brain interaction. In conclusion, a more complete functional and structural profile that these investigations enable should permit a greater understanding of the effects of dietary manipulation on the gastrointestinal tract and provide clinically relevant information that, amongst other advantages, might permit opportunities for personalized health care delivery.

Incidental Findings of Gallbladder and Bile Ducts-Management Strategies: General Aspects, Gallbladder Polyps and Gallbladder Wall Thickening-A World Federation of Ultrasound in Medicine and Biology (WFUMB) Position Paper

The World Federation of Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings with a series of position papers to give advice on characterization and management. The biliary system (gallbladder and biliary tree) is the third most frequent site for incidental findings. This first part of the position paper on incidental findings of the biliary system is related to general aspects, gallbladder polyps and other incidental findings of the gallbladder wall. Available evidence on prevalence, diagnostic work-up, malignancy risk, follow-up and treatment is summarized with a special focus on ultrasound techniques. Multiparametric ultrasound features of gallbladder polyps and other incidentally detected gallbladder wall pathologies are described, and their inclusion in assessment of malignancy risk and decision- making on further management is suggested.

Contrast-enhanced ultrasound using SonoVue mixed with oral gastrointestinal contrast agent to evaluate esophageal hiatal hernia: Report of three cases and a literature review

BACKGROUND

Due to a thicker abdominal wall in some patients, ultrasound artifacts from gastrointestinal gas and surrounding tissues can interfere with routine ultrasound examination, precluding its ability to display or clearly show the structure of a hernial sac (HS) and thereby diminishing diagnostic performance for esophageal hiatal hernia (EHH). Contrast-enhanced ultrasound (CEUS) imaging using an oral agent mixture allows for clear and intuitive identification of an EHH sac and dynamic observation of esophageal reflux.

CASE SUMMARY

In this case series, we report three patients with clinically-suspected EHH, including two females and one male with an average age of 67.3 ± 16.4 years. CEUS was administered with an oral agent mixture (microbubble-based SonoVue and gastrointestinal contrast agent) and identified a direct sign of supradiaphragmatic HS (containing the hyperechoic agent) and indirect signs [e.g., widening of esophageal hiatus, hyperechoic mixture agent continuously or intermittently reflux flowing back and forth from the stomach into the supradiaphragmatic HS, and esophagus-gastric echo ring (i.e., the “EG” ring) seen above the diaphragm]. All three cases received a definitive diagnosis of EHH by esophageal manometry and gastroscopy. Two lesions resolved upon drug treatment and one required surgery. The recurrence rate in follow-up was 0%. The data from these cases suggest that the new non-invasive examination method may greatly improve the diagnosis of EHH.

CONCLUSION

CEUS with the oral agent mixture can facilitate clear and intuitive identification of HS and dynamic observation of esophageal reflux.

Utility of gastrointestinal ultrasound in functional gastrointestinal disorders: A narrative review

Gastrointestinal (GI) ultrasound (GIUS) is valuable in the evaluation of GI diseases such as inflammatory bowel disease, but its use in functional GI disorders (FGIDs) is largely unknown although promising. In order to review the current knowledge on current and potential uses of GIUS in FGIDs, information was obtained via a structured literature search through PubMed, EMBASE and Google Scholar databases with a combination of MESH and keyword search terms: “ultrasound”, “functional GI disorders”, “irritable bowel syndrome”, “functional dyspepsia”, “intestinal ultrasound”, “point of care ultrasonography”, “transabdominal sonography”, “motility”, “faecal loading”, “constipation”. GIUS is currently used for various settings involving upper and lower GI tracts, including excluding organic diseases, evaluating physiology, guiding treatment options and building rapport with patients. GIUS can be potentially used to correlate mechanisms with symptoms, evaluate mechanisms behind treatment efficacy, and investigate further the origin of symptoms in real-time. In conclusion, GIUS is unique in its real-time, interactive and non-invasive nature, with the ability of evaluating several physiological mechanisms with one test, thus making it attractive in the evaluation and management of FGIDs. However, there are still limitations and concerns of operator dependence and lack of validation data for widespread implementation of GIUS in FGIDs.

Gastrointestinal ultrasound in inflammatory bowel disease: an underused resource with potential paradigm-changing application

Evolution of treatment targets in IBD has increased the need for objective monitoring of disease activity to guide therapeutic strategy. Although mucosal healing is the current target of therapy in IBD, endoscopy is invasive, expensive and unappealing to patients. GI ultrasound (GIUS) represents a non-invasive modality to assess disease activity in IBD. It is accurate, cost-effective and reproducible. GIUS can be performed at the point of care without specific patient preparation so as to facilitate clinical decision-making. As compared with ileocolonoscopy and other imaging modalities (CT and MRI), GIUS is accurate in diagnosing IBD, detecting complications of disease including fistulae, strictures and abscesses, monitoring disease activity and detecting postoperative disease recurrence. International groups increasingly recognise GIUS as a valuable tool with paradigm-changing application in the management of IBD; however, uptake outside parts of continental Europe has been slow and GIUS is underused in many countries. The aim of this review is to present a pragmatic guide to the positioning of GIUS in IBD clinical practice, providing evidence for use, algorithms for integration into practice, training pathways and a strategic implementation framework.

How to perform gastrointestinal ultrasound: Anatomy and normal findings

Gastrointestinal ultrasound is a practical, safe, cheap and reproducible diagnostic tool in inflammatory bowel disease gaining global prominence amongst clinicians. Understanding the embryological processes of the intestinal tract assists in the interpretation of abnormal sonographic findings. In general terms, the examination principally comprises interrogation of the colon, mesentery and small intestine using both low-frequency and high-frequency probes. Interpretation of findings on GIUS includes assessment of bowel wall thickness, symmetry of this thickness, evidence of transmural changes, assessment of vascularity using Doppler imaging and assessment of other specific features including lymph nodes, mesentery and luminal motility. In addition to B-mode imaging, transperineal ultrasonography, elastography and contrast-enhanced ultrasonography are useful adjuncts. This supplement expands upon these features in more depth.

A New Reliable Method for Evaluating Gallbladder Dynamics: The 3-Dimensional Sonographic Examination

OBJECTIVES

The purpose of this study was to compare conventional 2-dimensional (2D) B-mode sonography with 3-dimensional (3D) sonography for assessing gallbladder volume and contractility.

METHODS

Gallbladder volume and contractility were evaluated in 32 healthy volunteers after fasting and abstinence from smoking for 8 hours and after a standardized balanced liquid meal. The gallbladder was evaluated with 2D sonography (with the use of the ellipsoid method) and with 3D sonography using a volumetric matrix probe. Both measurements were made by an operator who was skilled in sonography and an unskilled operator. The group of volunteers was subdivided into 2 subgroups including 16 participants, which represented the "2 moments" of acquisition by the techniques, particularly for the unskilled operator.

RESULTS

The postprandial volumes obtained with 3D sonography were significantly lower in comparison to the volumes obtained with 2D sonography (P= .013), and there was a significant difference between the measurements made by the skilled and unskilled operators only for 2D sonography (P< .001), whereas between the 2 moments of acquisition by the 3D technique, there was no significant difference. The reproducibility of the technique for evaluation of gallbladder volumes was higher for 3D sonography than 2D sonography, particularly for the postprandial evaluation.

CONCLUSIONS

The new 3D sonographic method using a volumetric matrix probe is a simple, reliable, and more reproducible technique than conventional 2D sonography, even if performed by an unskilled operator, and it allows a reliable stimulation test for a gallbladder dynamic study.

US of gastrointestinal tract disease

The potential use of ultrasonography (US) in evaluating gut disease has been underappreciated in most diagnostic imaging departments in North America. The impression that US has a questionable role in bowel assessment is related to the operator-dependent nature of the modality, the technical challenges of performing bowel US examinations, and the lack of familiarity of radiologists and technologists with the US appearances of normal and abnormal bowel. However, with development of technical experience by the sonographer and integration of a clinical focus at patient evaluation, US can become a powerful tool for bowel assessment. Unlike computed tomography and magnetic resonance imaging, it provides a widely available, noninvasive, inexpensive method for evaluating the gut without the use of ionizing radiation. These factors are of particular importance in young patients and those who require recurrent follow-up imaging. Because US is performed with real-time imaging, the modality also allows the sonographer to view and assess the motility properties of the bowel, a feature that has not been previously used to its full potential. Color Doppler US can yield useful information about mural vascularity in bowel disease when used in conjunction with gray-scale findings and clinical symptoms. Radiologists should be familiar with the static and dynamic US appearances of the normal and abnormal bowel, recognize features of various pathologic conditions, and understand potential errors at imaging interpretation. Online supplemental material is available for this article.

Feasibility and usefulness of using swallow contrast-enhanced ultrasound to diagnose Zenker's diverticulum: preliminary results

Zenker's diverticulum (ZD) may be misdiagnosed on conventional ultrasound as a thyroid nodule or other lesion. A barium esophagram is usually used to confirm the diagnosis; however, this procedure exposes the patient to radiation. The aim of this study was to evaluate the feasibility of using swallow contrast-enhanced ultrasound (swallow-CEUS) to diagnose ZD. Ten consecutive patients with ZD (7 men and 3 women, aged 67 ± 11 y) were included in the study. In 4 patients, ZD was incidentally found on head and neck ultrasound, and in 6 patients, ZD was suspected because of dysphagia. All lesions could be detected on conventional ultrasound before swallow-CEUS. Ten healthy volunteers (8 men and 2 women, aged 60 ± 12 y) were chosen as a control group. Written informed consent was obtained. With the patient in the sitting or upright position, conventional ultrasound was performed first to image the lesion, then the patient was asked to swallow ultrasound contrast agent (UCA) (2-4 drops of SonoVue diluted with about 200 mL of tap water). Transity of the contrast agent in the esophagus was imaged with CEUS. Retention of the UCA in the diverticulum was monitored for at least 3 min. All patients underwent a barium esophagram as the gold standard. Swallow-CEUS revealed that in all patients (100%), the UCA was transported from the pharynx to the esophagus while the patient swallowed. ZD appeared as a pouch-shaped structure at the posterior pharyngo-esophageal junction that retained UCA longer than 3 min. The barium esophagram confirmed the diagnosis of ZD in all patients. For the 10 volunteers, no abnormal structure (retaining UCA) was detected during or after swallowing of UCA. With the advantages of no radiation and bedside availability, swallow-CEUS may become a method of choice in confirmation of the diagnosis of ZD, especially when ZD is suspected on conventional ultrasound.

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

BACKGROUND

The stimulation and intragastric accumulation of gastric secretion has been recognized as an important factor in gastroesophageal reflux disease. However, the interaction of gastric secretion and meal emptying has not been fully understood. Current methods to assess gastric secretion are either invasive or unable to provide information on its volume, distribution and dynamics. The aim of this study was to quantify the interaction between meal emptying and meal induced gastric secretion by using quantitative magnetic resonance imaging (MRI) and pharmacokinetic analysis.

METHODS

A chocolate test meal was developed which is secretion stimulating and MRI compatible. Meal emptying and gastric secretion were assessed in fourteen healthy volunteers using a validated quantitative MRI technique. A population based pharmacokinetic model was developed and applied to the extracted volume data, assessing the meal emptying rate, rate of secretion and their interaction.

KEY RESULTS

The test meal continuously induced gastric secretion in all subjects, which partly accumulated at the meal-air interface, forming a 'secretion layer' in the proximal stomach. Traditional fitting detected a significant correlation between meal emptying rate and rate of secretion. The pharmacokinetic model quantified this interaction and estimated a 2.3 ± 1 fold higher effect of meal on secretion than vice versa. The efficacy of the emptied meal to produce gastric secretion was 61%.

CONCLUSIONS & INFERENCES

The combined quantitative MRI and pharmacokinetic model approach allows for the quantification of gastric secretion volume and its interaction on meal emptying. The observed secretion layer might explain previous findings postulating the presence of an intragastric 'acid pocket'.

Floating microspheres: a review

Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI) transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.

Gastroesophageal reflux disease: From pathophysiology to treatment

This review focuses on the pathophysiology of gastroesophageal reflux disease (GERD) and its implications for treatment. The role of the natural anti-reflux mechanism (lower esophageal sphincter, esophageal peristalsis, diaphragm, and trans-diaphragmatic pressure gradient), mucosal damage, type of refluxate, presence and size of hiatal hernia, Helicobacter pylori infection, and Barrett’s esophagus are reviewed. The conclusions drawn from this review are: (1) the pathophysiology of GERD is multifactorial; (2) because of the pathophysiology of the disease, surgical therapy for GERD is the most appropriate treatment; and (3) the genesis of esophageal adenocarcinoma is associated with GERD.

Technical advances in monitoring human motility patterns

Abnormal motor patterns are implicated in many motility disorders. However, for many regions of the gut, our knowledge of normal and abnormal motility behaviors and mechanisms remains incomplete. There have been many recent advances in the development of techniques to increase our knowledge of gastrointestinal motility, some readily available while others remain confined to research centers. This review highlights a range of these recent developments and examines their potential to help diagnose and guide treatment for motility disorders.