Gastrointestinal Ultrasound in Emergency Setting

Abstract

Acute bowel diseases are responsible for more than one third of subjects who were referred to the emergency department for acute abdominal pain and gastrointestinal evaluation. Gastrointestinal ultrasound (GIUS) is often employed as the first imaging method, with a good diagnostic accuracy in the setting of acute abdomen, and it can be an optimal diagnostic strategy in young females due to the radiation exposure related to X-ray and computed tomography methods. The physician can examine the gastrointestinal system in the area with the greatest tenderness by ultrasound, thus obtaining more information and data on the pathology than the standard physical examination. In this comprehensive review, we have reported the most relevant indications and advantages to using ultrasound in the investigation of abdominal acute pain.

Keywords: abdomen; bowel; emergency; inflammation; ultrasound.

Figure 1

Image obtained with a high frequency linear probe. Longitudinal scan on the parietal stratification of bowel loop: the innermost portion represents the lumen, the first layer (hyperechoic) represents the interface between the mucosa and the lumen, the second layer (hypoechoic) to the mucosa, the third layer (hyperechoic) to the submucosa, the fourth layer (hypoechoic) to the muscolaris propria and fifth layer (hyperechic) to the interface echo between the muscolaris and the serosa.

Figure 2

Transverse scan image of a normal bowel loop, in which the succession of hyperechoic and hypoechoic layers is evident.

Figure 3

Figures representing Crohn ileitis: the walls are diffusely thickened (white arrows) and a clear distinction between the different parietal layers is lost; the thickening and distortion of the wall can be such as to determine a stenosis of the colon section involved; in the last figure a Crohn ileitis complication is represented [fluid collection (yellow arrow)].

Figure 4

Patient went to the emergency room reporting diffuse abdominal pain for about 10 days associated with diarrhea and traces of blood and mucus, and weight loss (about 10 kg). GIUS showed diffuse wall thickening of the entire colon, particularly at the level of the ileocecal valve (11 mm) and submucosa thickness of 6 mm; multiple lymph nodes were evident in the right iliac area, with a maximum size of 11 mm. The clinical and ultrasound findings are compatible with Crohn’s disease.

Figure 5

Image obtained with a low frequency convex probe. There is a coarse echogenic formation adjacent to the ileocecal valve which presents a clear wall thickening. Image obtained from a patient with CD who was referred to the emergency room for fever and abdominal pain in the right iliac fossa; final diagnosis of CD acute flare with phlegmon.

Figure 6

Images obtained with a high frequency linear probe. The image (a) shows a transversal scan of a section of colon with thickened walls (ulcerative colitis diagnosis); there is a hypertrophic feature of the submucosa layer. In image (b) the color function is inserted, which shows a hypervascularization of the wall, compatible with acute ulcerative colitis flare.

Figure 7

Images of a case of appendicitis. In figures (a,b) a longitudinal scan of the appendix is evident, which presents thickened walls and a hypoechoic appearance; compression with the probe does not allow the lumen to collapse and this maneuver evokes elective pain; In figure (c) the appendix is visualized in cross scan (white circle); In figure (d) multiple lymph nodes are evident in the right iliac fossa (white arrow).

Figure 8

The image represents a section of the descending colon with diffusely thickened and hypoechoic walls; in particular, there are multiple outpourings of the wall, compatible with diverticula.

Figure 9

Image obtained by a linear probe. There is evidence of bowel wall thickening and parietal outpouring (white arrow) of a section of the descending colon, compatible with a diverticulum. The hypoechoic formation extends into the surrounding fatty tissue, which appears hyperechoic (red arrow). The findings appear indicative of acute diverticulitis.

Figure 10

Images obtained with a high frequency linear probe. Sigmoid tract with thickened walls and evidence of a diverticular formation of the wall with an aerial artifact inside it (b). The peri-sigmoid adipose tissue is thickened and hyperechoic. In image (a) an anechoic area is also visible which from the sigmoid wall moves towards the surrounding adipose tissue, suggestive for abscess area.

Figure 11

Image obtained with convex probe. There is an overdistension of the stomach with clear evidence of echoes inside it from ingestion. Final diagnosis of duodenal cancer with overdistention of the stomach upstream.

Figure 12

Image obtained with convex probe. Dilated loops of small intestine, with fecal material inside and thinned walls. Diagnosis of small bowel obstruction due to adhesions.

Figure 13

Image obtained with convex probe. Dilated small bowel loops, with evidence of Kerckring valves also called valvulae conniventes (“keyboard sign”), and corpuscular material inside. In live examination there is a to-and-fro movement. Diagnosis: small bowel obstruction due to adhesions.

Figure 14

A dilated loop of the small intestine is visualized, with complete loss of wall stratification and diffuse hypoechoic appearance of the wall. In live examination, peristalsis was abolished at the level of that bowel tract. Upon CEUS, there was no parietal perfusion. Image obtained from a patient with newly diagnosed atrial fibrillation and diagnosis of intestinal ischemia (embolic nature).