Ultrasonography in gastroenterology

Gastric Emptying of Low- and High-Caloric Liquid Meals Measured Using Ultrasonography in Healthy Volunteers

Purpose

Delayed gastric emptying is present in patients with functional dyspepsia (FD), diabetes mellitus, and neurological diseases. Diet may affect gastric emptying symptoms in patients with FD. We sought to determine the extent to which gastric emptying and symptoms of dyspepsia are influenced by caloric content in healthy subjects using ultrasonography.

Materials and Methods

32 healthy volunteers were given 2 meals with different caloric content in random order. Gastric emptying was determined using ultrasonography to measure antral area when fasting, and postprandially at intervals of 0, 10, 20, and 30 min. Dyspeptic symptoms including discomfort, nausea, and fullness were graded.

Results

The antral area following a high-caloric meal compared to a low-caloric meal was significantly increased at 0, 10, 20, and 30 min (P=0.0203,<0.0001<0.0001,<0.0001, respectively), as was the median fullness (P<0.0048, 0.0001, 0.0009, 0.0001, respectively) measured at the same time points. There was a weak correlation (r2=0.1, P<0.0001) between the antral area and subjective fullness. No differences between gastric emptying in males and females were found.

Conclusion

The caloric content of a meal influences gastric emptying. Using ultrasonography to measure the antral area helps us to assess gastric emptying and therefore to assess patients with functional dyspepsia.

Transabdominal ultrasound elastography of the esophagogastric junction predicts reflux esophagitis

PURPOSE

Abdominal ultrasound (US) can visualize the esophagogastric junction (EGJ) as a hyperechoic area in the dorsal portion of the lateral segment of the liver. We prospectively evaluated the EGJ using US elastography (US-EG) in patients with reflux esophagitis (RE) to examine prediction of distal esophageal function.

METHODS

Of 108 patients undergoing US-EG and esophagogastroduodenoscopy, 102 in whom the EGJ was observed for ≥ 15 s were included. The subjects were divided into a RE group (n = 41, Grade M/A/B:24/13/4 according to modified Los Angeles Classification) and a non-RE group (n = 61). Direct strain elastography (LOGIQ E9, GE Healthcare), which gives a semi-quantitative elasticity index within a region of interest including the lateral segment, was used as a standard for measurement of the change in stiffness (CS) at the EGJ.

RESULTS

The number of CS as determined by US-EG was 6.0 (5.5-6.7) in the RE group and 8.6 (6.6-10.0) in the non-RE group (P < 0.0001). In ROC analysis, the AUC was 0.8415 for diagnosis of RE using the number of CS. At a cut-off of 7.7, the sensitivity, specificity, and accuracy for diagnosis were 92.7, 65.6, and 74.5%, respectively.

CONCLUSION

The presence of RE can be predicted based on US-EG.

Ultrasonography in Gastroenterology: The Need for Training

The use of ultrasonography (US) as an imaging modality in medicine has spread across almost every clinical specialty. This diffusion is based on the simplicity, accessibility, portability and affordability of the technique producing real-time high-resolution images using non-ionising radiation. On the other hand, this trend also extended the technique to settings other than healthcare, such as public facilities, private houses or remote sites. This tendency can be observed worldwide, from developing countries to prestigious medical schools and tertiary referral hospitals. Furthermore, point-of-care US (POCUS), i.e., US executed at the patient's bedside to obtain real-time objective information with diagnostic and clinical monitoring purposes or to guide invasive procedures, has been incorporated in many specialties. In gastroenterology, despite the essential role of endoscopy, clinical practice is highly dependent on non-endoscopic imaging techniques. However, as in other specialties, the indications of US in gastroenterology have been increasing steadily, covering a broad range of conditions. In response to the generalised employment of US by non-radiologists, institutions such as the European Federation of Societies for Ultrasound in Medicine and Biology and the Royal College of Radiologists issued recommendations to ensure high-quality practice. These theoretical and practical requisites include performing a certain number of examinations and mandatory skills in order to achieve certification to execute unsupervised US. Therefore, there is a need for modern gastroenterology to include US as a basic skill in its clinical practice. To ensure the provision of high-quality US, adequate instruction of future specialists should be guaranteed by the gastroenterology departments and required in the residency training programme.

Prolonged intestinal transit and diarrhea in patients with an activating GUCY2C mutation

Introduction

Increased intestinal hydration by activation of the epithelial enzyme linked receptor guanylate cyclase C (GC-C) is a pharmacological principle for treating constipation. Activating mutations in the GUCY2C gene encoding GC-C cause Familial GUCY2C diarrhea syndrome (FGDS) which has been diagnosed with severe dysmotility.

Aim

To investigate gut motility and hormones before and after a meal in FGDS patients and compare with healthy controls (HC).

Subjects and methods

Bristol stool chart and stool frequency was assessed. Before and after a meal occlusive and non-occlusive contractions were obtained using ultrasound. A wireless motility capsule (WMC) recorded gut transit time, pH, contractions and pressure. Plasma levels of selected gut hormones were measured at different time points.

Results

The FGDS patients had 4 (range 1–10) loose stools/day and prolonged total gut transit time compared to HC, 55.5 h vs 28.5 h, respectively,with significantly increased colon transit time. In FGDS patients, pH in duodenum, small bowel and colon was increased and the number of contractions and the intraluminal pressure were significantly decreased, measured by WMC. Ultrasound showed in small bowel increased number of non-occlusive contractions in the FGDS patients. Serotonin (5-HT) plasma levels in the HC peaked 30 min after the meal, while the FGDS patients had no response.

Conclusion

Despite having diarrhea, the FGDS patients have prolonged transit time through the gut compared to HC, particularly in colon. The reduced number of intestinal contractions and lack of 5-HT release after a meal in FGDS patients surprisingly resemble colonic motility disturbances seen in patients with constipation.