Imaging evaluation of bowel obstruction in children: updates in imaging techniques and review of imaging findings

Diagnostic Yield of Abdominal Radiographs in the Pediatric Emergency Department

BACKGROUND AND OBJECTIVES

Abdominal radiographs (ARs) are commonly used in the pediatric emergency department (PED). Their low diagnostic accuracy leads to overuse, excess radiation exposure, and increased resource usage. This study aims to assess the diagnostic yield of ARs in the evaluation of intraabdominal pathology in the PED.

METHODS

Retrospective, cross-sectional study of patients aged 0 to 18 years with an AR who visited the PED between 2017 and 2019. Diagnostic yield was analyzed with sensitivity, specificity, positive predictive value, negative predictive value (NPV), and likelihood ratio.

RESULTS

A total of 4288 ARs were identified, with a rate of 6%. The overall abnormal AR rate was 31%. The incidences of an abnormal AR in abdominal pain, vomiting, and constipation were 26%, 37%, and 50%, respectively. There was a 13% rate of clinically significant diagnoses. The AR diagnostic yield showed 44% sensitivity, 70% specificity, 17% positive predictive value, and 90% NPV ( P < 0.05). Unadjusted odds ratio analysis of positive AR and abdominal pain, vomiting, and constipation revealed an odds ratio of 0.68 (95% confidence interval [CI], 0.63-0.75), 1.22 (95% CI, 1.06-1.39), and 1.72 (95% CI, 1.54-1.91), respectively.

CONCLUSIONS

There is a low rate of intraabdominal pathologic processes that an AR can identify. A normal AR does not change patient management, nor does it reduce the need for further radiologic imaging. Despite a good NPV, the AR is not a useful diagnostic tool in the PED because of its limited ability to rule in or rule out clinically significant diagnoses.

Ultrasound in the evaluation of necrotic bowel in children: A pictorial essay

Necrotic bowel is a serious condition involving death of gastrointestinal tissue. The diagnosis is difficult to make clinically, and plain radiography is often inconclusive. Ultrasonography is an inexpensive, portable and readily available complementary diagnostic tool. In some cases, ultrasonography can detect features of necrotic bowel earlier than plain radiography or when plain radiography is equivocal and does not correlate with the clinical findings. This pictorial essay aims to compare the ultrasonography features of normal bowel and necrotic bowel in children. The role of ultrasonography and the ultrasonographic features of necrotic bowel will be illustrated by discussing some of the causes of necrotic bowel in children. Correlation with plain radiographs and pathological specimens is made. Frequent causes of necrotic bowel in neonates include necrotising enterocolitis, malrotation with small bowel volvulus and incarcerated inguinal hernias. Causes in older children include intussusception, complications of Meckel's diverticulum, post-surgical adhesions, internal hernias and vasculitic abnormalities. Ultrasonography features suggestive of necrotic bowel include persistently dilated loops of aperistaltic bowel, increase or decrease of bowel wall thickness, intramural or portal venous gas, loss of bowel wall perfusion, and free intraperitoneal gas and fluid. The diagnosis of necrotic bowel may be made earlier on ultrasonography than on abdominal radiographs alone. This pictorial essay will familiarise the reader with the role of ultrasonography and the ultrasonographic features of necrotic bowel through a wide range of conditions that may cause necrotic bowel in children. Familiarity with these findings will facilitate timely imaging diagnosis of necrotic bowel before complications develop.

Ultrasonographic and computed tomographic characterization and localization of suspected mechanical gastrointestinal obstruction in dogs

OBJECTIVE To evaluate the usefulness of noncontrast abdominal CT and abdominal ultrasonography for the detection of mechanical gastrointestinal obstruction in dogs and compare intestinal diameter ratios between dogs with and without obstruction. DESIGN Controlled trial. ANIMALS 16 client-owned dogs with physical and radiographic findings consistent with mechanical gastrointestinal obstruction. PROCEDURES Abdominal ultrasonography and CT were performed for all dogs, followed by laparoscopy and exploratory laparotomy. Time required for image acquisition and presence and location of gastrointestinal obstruction were assessed with both imaging modalities. Findings were compared with those of exploratory surgery. Maximum and minimum intestinal diameters were recorded on CT scans; values were converted to a ratio and compared between dogs with and without obstruction. RESULTS Results of abdominal CT and exploratory surgery for the diagnosis of mechanical obstruction agreed for all 16 dogs; 10 dogs had complete obstruction, 3 had partial obstruction, and 3 had no obstruction. In 1 dog with functional ileus, abdominal ultrasonography resulted in an incorrect diagnosis of mechanical obstruction. Median (interquartile range) image acquisition time for abdominal CT (2.5 minutes [2.0 to 3.8 minutes]) was markedly and significantly shorter than that for ultrasonography (26.0 minutes [22.0 to 35.8 minutes]). In both dorsal and transverse CT planes, dogs with gastrointestinal obstruction (partial or complete) had significantly larger intestinal diameter ratios than dogs without obstruction. CONCLUSIONS AND CLINICAL RELEVANCE Abdominal CT was feasible, rapid, and accurate for the diagnosis of mechanical obstruction in dogs with clinical signs and physical examination findings consistent with partial or complete gastrointestinal obstruction.

Pelvic pain in the middle of the night: use of MRI for evaluation of pediatric female pathology in the emergent setting

Acute pelvic pain in pediatric female patients is a common cause of emergency room visits. Imaging plays a crucial role in the clinical evaluation of these patients. Pelvic pain in female children can result from various pathologies. Ultrasound is the preferred first line imaging study; however, magnetic resonance imaging (MRI) is a helpful adjunct after hours, as it is available 24/7 in many institutions. Advantages of MRI include superior delineation of anatomy and higher tissue contrast resolution, particularly of the small pelvic structures. Given the lack of ionizing radiation, there is increasing use of MRI in children and adolescents, specifically in an emergent setting. In this pictorial review, we discuss pelvic MRI techniques and illustrate imaging findings of common etiologies of pelvic pain, emphasizing the advantages of MRI as an adjunct imaging modality.

Abdominal ultrasonography of the pediatric gastrointestinal tract

Ultrasound is an invaluable imaging modality in the evaluation of pediatric gastrointestinal pathology; it can provide real-time evaluation of the bowel without the need for sedation or intravenous contrast. Recent improvements in ultrasound technique can be utilized to improve detection of bowel pathology in children: Higher resolution probes, color Doppler, harmonic and panoramic imaging are excellent tools in this setting. Graded compression and cine clips provide dynamic information and oral and intravenous contrast agents aid in detection of bowel wall pathology. Ultrasound of the bowel in children is typically a targeted exam; common indications include evaluation for appendicitis, pyloric stenosis and intussusception. Bowel abnormalities that are detected prenatally can be evaluated after birth with ultrasound. Likewise, acquired conditions such as bowel hematoma, bowel infections and hernias can be detected with ultrasound. Rare bowel neoplasms, vascular disorders and foreign bodies may first be detected with sonography, as well. At some centers, comprehensive exams of the gastrointestinal tract are performed on children with inflammatory bowel disease and celiac disease to evaluate for disease activity or to confirm the diagnosis. The goal of this article is to review up-to-date imaging techniques, normal sonographic anatomy, and characteristic sonographic features of common and uncommon disorders affecting the gastrointestinal tract in children.

Gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy in the years 2000

AIM: To review gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy. To look at gut microflora features in oncology children.

METHODS: We selected studies published after year 2000, excluding trials on transplanted pediatric patients. We searched English language publications in MEDLINE using the keywords: “gastrointestinal infection AND antineoplastic chemotherapy AND children”, “gastrointestinal infection AND oncology AND children”, “liver infection AND antineoplastic chemotherapy AND children”, “liver abscess AND chemotherapy AND child”, “neutropenic enterocolitis AND chemotherapy AND children”, “thyphlitis AND chemotherapy AND children”, “infectious diarrhea AND children AND oncology”, “abdominal pain AND infection AND children AND oncology”, “perianal sepsis AND children AND oncology”, “colonic pseudo-obstruction AND oncology AND child AND chemotherapy”, “microflora AND children AND malignancy”, “microbiota AND children AND malignancy”, “fungal flora AND children AND malignancy”. We also analysed evidence from several articles and book references.

RESULTS: Gastrointestinal and liver infections represent a major cause of morbidity and mortality in children undergoing antineoplastic chemotherapy. Antineoplastic drugs cause immunosuppression in addition to direct toxicity, predisposing to infections, although the specific risk is variable according to disease and host features. Common pathogens potentially induce severe diseases whereas opportunistic microorganisms may attack vulnerable hosts. Clinical manifestations can be subtle and not specific. In addition, several conditions are rare and diagnostic process and treatments are not standardized. Diagnosis may be challenging, however early diagnosis is needed for quick and appropriate interventions. Interestingly, the source of infection in those children can be exogenous or endogenous. Indeed, mucosal damage may allow the penetrance of endogenous microbes towards the bowel wall and their translocation into the bloodstream. However, only limited knowledge of intestinal dysbiosis in oncology children is available.

CONCLUSION: The diagnostic work-up requires a multimodal approach and should be implemented (also by further studies on new biomarkers) for a prompt and individualized therapy.

Abdominal emergencies in pediatrics

Abdominal symptoms are among the most common reasons for pediatric emergency department visits, and abdominal pain is the most frequently reported symptom. Thorough history taking and physical examination can often reach the correct diagnosis. Knowing the abdominal conditions that are most common in each age group can help radiologists narrow the differential diagnosis. When imaging tests are indicated, ultrasonography is usually the first-line technique, enabling the diagnosis or adding relevant information with the well-known advantages of this technique. Nowadays, plain-film X-ray studies are reserved for cases in which perforation, bowel obstruction, or foreign body ingestion is suspected. It is also important to remember that abdominal pain can also occur secondary to basal pneumonia. CT is reserved for specific indications and in individual cases, for example, in patients with high clinical suspicion of abdominal disease and inconclusive findings at ultrasonography. We review some of the most common conditions in pediatric emergencies, the different imaging tests indicated in each case, and the imaging signs in each condition.

Sonography of the pediatric gastrointestinal system

Sonography is a commonly used modality for the investigation of abdominal symptoms in the pediatric population. It is a highly sensitive, readily available imaging modality that does not require ionizing radiation, iodinated contrast material, or anesthesia and can be performed at the bedside if necessary. Abdominal ultrasound is therefore often the first examination performed. This article presents an overview of the ultrasound characteristics of some of the most frequently encountered pathologies as well as some more rarely encountered entities. Our aim was to present a series of characteristic images of a wide gamut of pediatric abdominal conditions. The goal was to familiarize the reader with key sonographic features of both congenital and acquired gastrointestinal pathologies in children, making them more easily recognizable.

Intussusception in childhood: role of sonography on diagnosis and treatment

OBJECTIVE

The aim of this study was to determine the role of ultrasound in the diagnosis and treatment of pediatric patients with acute abdominal pain caused by intussusceptions.

MATERIALS AND METHODS

We performed a retrospective study of all pediatric patients with acute abdominal pain caused by intussusceptions and that underwent ultrasound examination at the emergency service of the Radiology Department between November 2007 and June 2013. The role of ultrasonography in the diagnosis of intussusceptions has been assessed by comparing the echographic presumptive diagnosis with the final diagnosis of discharge. Its importance in the treatment has been assessed by determining the value of ultrasound findings in the choice of the best treatment.

RESULTS

The ultrasound examination was positive in 16/18 patients with a final diagnosis of intussusception. Some sonographic findings seemed to be able to predict the opportunity to resort to non-surgical therapeutic options like hydrostatic or pneumatic reduction of the intestinal segments invaginated. In our casuistry, five children presented characteristics typical of this subgroup and underwent barium enema which provided the reduction of the intestinal segments involved. The future challenge will be to perform non-surgical ultrasound-guided reductions to avoid the exposure of the infants to ionizing radiations.

CONCLUSIONS

Ultrasonography is essential not only in the diagnosis, but also it adds important elements in the therapeutic choice and could play in the future an important role in non-surgical reduction of intestinal intussusceptions in pediatric patients.

Common and uncommon applications of bowel ultrasound with pathologic correlation in children

OBJECTIVE

The purpose of this article is to describe the indications and techniques for bowel ultrasound for inflammatory bowel disease and other common and uncommon entities and describe and illustrate their imaging appearances, including endoscopic or surgical correlation.

CONCLUSION

Ultrasound is a useful tool for the evaluation of inflammatory bowel disease and many other bowel diseases. Radiologists must become familiar with the full potential of ultrasound in the evaluation of the bowel in children because the need for alternative radiation-free imaging techniques continues to grow.

A descriptive study of transient neonatal feeding intolerance in a tertiary care center in Turkey

OBJECTIVE

To investigate the characteristic features of transient neonatal feeding intolerance (TNFI) during the hospitalization for birth in the maternity ward.

DESIGN

A prospective follow-up study.

SETTING

Maternity ward and neonatal intensive care unit (NICU) in an academic medical center.

PARTICIPANTS

Term (≥ 37-weeks gestation) infants admitted to the neonatal intensive care unit with recurrent vomiting and refusal to feed between January and December 2011. These infants were prospectively followed-up at 1, 2, 4, 6 months of age in the outpatient clinic.

RESULTS

During the study period 1280 infants were evaluated in the maternity ward. Forty-eight (3.75%) neonates with repeated vomiting and refusal to feed were hospitalized from the maternity unit to the NICU Level I on the first postnatal day for further investigation. All infants started vomiting in the first day (median 5.75 hours; interquartile range: 1-24) and recovered by the 48(th) postnatal hour (median 27.5 hours; interquartile range: 14-48 hours). Laboratory and imaging studies showed no abnormalities. After discharge, 6-month follow-up of these infants showed no vomiting or feeding intolerance during well-child visits.

CONCLUSIONS

Infants with TNFI can be managed with close observation and supportive measures if they have no other indications of underlying disease. We believe that expectant management and supportive measures under skilled nursing care will prevent unnecessary diagnostic evaluation, mother/infant separation, and prolonged hospital stay.

Magnetic resonance enterography: inflammatory bowel disease and beyond

This article addresses the current technique and protocols for magnetic resonance (MR) enterography, with a primary focus on inflammatory bowel disease (IBD) and a secondary detailed discussion of other diseases of the small bowel beyond IBD. A brief discussion of MR imaging for appendicitis is included, but the evaluation of appendicitis does not require an enterographic protocol. The focused key points and approach presented in this article are intended to enhance the reader's understanding to help improve patient compliance with the MR enterographic studies, overcome challenges, and improve interpretation.