Ultrasound imaging of bowel obstruction in neonates

Bowel obstruction (BO) in children has a wide differential diagnosis, ranging from non-urgent conditions to surgical emergencies. Abdominal radiographs are most often used as the first imaging modality for the evaluation of obstruction. However, for some indications, ultrasound can be the primary imaging modality. Therefore, it is incumbent on radiologists to recognize the types of bowel obstruction that can be recognized with US. Key sonographic features of BO include differential dilation of bowel loops, bowel wall thickening, and free fluid. "Do Not Miss" findings that indicate need for emergent treatment include volvulus, pneumoperitoneum, and/or signs of ischemia (bowel wall thinning and/or absent perfusion). The aim of this pictorial essay is to provide guidance on the sonographic technique and findings that enable identification of BO on US. Examples of neonatal BO on US, including common and less frequently encountered etiologies, are illustrated in this pictorial essay.

The “Black Pattern”, a Simplified Ultrasound Approach to Non-Traumatic Abdominal Emergencies

Background: A key issue in abdominal US is the assessment of fluid, which is usually anechoic, thus appearing “black”. Our approach focuses on searching for fluid in non-traumatic patients, providing a new, simplified method for point-of-care US (POCUS). Objective: Fluid assessment is based on a three-step analysis that we can thus summarize. 1. Look for black where it should not be. This means searching for effusions or collections. 2. Check if black is too much. This means evaluating anatomical landmarks where fluid should normally be present but may be abnormally abundant. 3. Look for black that is not clearly black. This means evaluating fluid aspects, whether wholly anechoic or not (suggesting heterogeneous or corpusculated fluid). Discussion: Using this simple method focused on US fluid presence and appearance should help clinicians to make a timely diagnosis. Although our simplified, systematic algorithm of POCUS may identify abnormalities; this usually entails a second-level imaging. An accurate knowledge of the physio–pathological and anatomical ultrasound bases remains essential in applying this algorithm. Conclusion: The black pattern approach in non -traumatic emergencies may be applied to a broad spectrum of abnormalities. It may represent a valuable aid for emergency physicians, especially if inexperienced, involved in a variety of non-traumatic scenarios. It may also be a simple and effective teaching aid for US beginners.

Bowel ultrasonography in acute abdomen: beyond acute appendicitis

Acute abdomen is a common reason for consultation in the emergency department. A broad spectrum of entities, including diverse diseases of the gastrointestinal tract, can cause acute abdomen. Although computed tomography is the technique most widely used to evaluate acute abdomen in the emergency department, abdominal ultrasound is often performed first and allows bowel disease to be suspected. This article describes the ultrasound features of diverse bowel diseases that can cause acute abdomen, such as acute diverticulitis, bowel obstruction, gastrointestinal perforation, bowel ischemia, intraabdominal fat necrosis, and miscellaneous processes such as endometriosis, foreign bodies, or vasculitis. Radiologists must be familiar with the different features of abnormal bowel that can be detected incidentally in patients without clinical suspicion of bowel disease. This article focuses on ultrasonographic signs of bowel disease; other articles in this series cover the ultrasonographic signs of acute appendicitis, inflammatory bowel disease, and infectious diseases.

Hyperechoic Abdominal Fat: A Sentinel Sign of Inflammation

One of the most useful sonographic signs of acute abdominal inflammation is the identification of increased echogenicity of the surrounding fat. Hyperechoic fat results from vasodilation and edema extending from an adjacent source of infection or inflammation. These changes are mediated by such factors such as bradykinin, histamine, and various cytokines. The recognition of hyperechoic fat on sonography may be an important indicator of the primary source of pathology. In addition, it often reflects a more advanced degree of transmural pathology, such as "walled-off" perforation of a hollow viscus. This pictorial essay will present a variety of examples of hyperechoic inflamed fat involving different abdominal organs and will illustrate the diagnostic value of this finding.

The value of ultrasound in diagnosis of pneumoperitoneum in emergent or critical conditions: A meta-analysis

Background:

Hollow organs perforation is a life-threatening condition. Early diagnosis and emergent intervention are important. Bedside ultrasound may be an alternative diagnostic tool for this condition.

Objective:

The aim of this study was to explore the diagnostic value of ultrasound of pneumoperitoneum in emergent or critical conditions through meta-analysis.

Methods:

PubMed, EMBASE, and Cochrane Library were systematically searched for potential studies. Then, two reviewers performed the processes of study selection, data extraction, and quality assessment independently. Finally, diagnostic indexes were analyzed with STATA 12.0 software (Serial No. 40120519635).

Results:

A total of five studies with moderate to high quality were eligible for meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio and their 95% confidence interval were 0.91 (95% confidence interval = 0.86–0.94), 0.96 (95% confidence interval = 0.75–0.99), 22.05 (95% confidence interval = 3.10–156.96), and 0.10 (95% confidence interval = 0.07–0.15), respectively. The area under the summary receiver operating characteristic curve was 0.92 (95% confidence interval = 0.90–0.94).

Conclusion:

Abdominal ultrasound is a useful alternative tool in diagnosing of pneumoperitoneum. However, due to limited evidence, it is not yet indicated for routine clinical use.

Small Bowel Perforations: What the Radiologist Needs to Know

The incidence of small bowel perforation is low but can develop from a variety of causes including Crohn disease, ischemic or bacterial enteritis, diverticulitis, bowel obstruction, volvulus, intussusception, trauma, and ingested foreign bodies. In contrast to gastroduodenal perforation, the amount of extraluminal air in small bowel perforation is small or absent in most cases. This article will illustrate the main aspects of small bowel perforation, focusing on anatomical reasons of radiological findings and in the evaluation of the site of perforation using plain film, ultrasound, and multidetector computed tomography equipments. In particular, the authors highlight the anatomic key notes and the different direct and indirect imaging signs of small bowel perforation.

Imaging Patients With Alimentary Tract Perforation: Literature Review

Alimentary tract perforation is a frequent emergency condition. Imaging plays an important role to make an accurate diagnosis, defining the presence, the level, and the cause of the perforation, essential information to enable the most correct therapeutic choice. Plain radiography is generally performed as the first choice. In case of a clinically suspected bowel perforation, not detected on x-ray imaging, the contribution of computed tomography is essential. Magnetic resonance is not yet widely used in diagnostic workup of patients with acute abdominal pain, but it can be useful in the differential diagnosis of acute abdomen in specific patients (pregnancy and pediatric patients).