Radiologists' agreement when using a 10-point scale to report abdominal radiographic findings of necrotizing enterocolitis in neonates and infants

Development of a Prediction Model for Surgery or Early Mortality at the Time of Initial Assessment for Necrotizing Enterocolitis

OBJECTIVE

 No available scale, at the time of initial evaluation for necrotizing enterocolitis (NEC), accurately predicts, that is, with an area under the curve (AUC) ≥0.9, which preterm infants will undergo surgery for NEC stage III or die within a week.

STUDY DESIGN

 This is a retrospective cohort study (n = 261) of preterm infants with <33 weeks' gestation or <1,500 g birth weight with either suspected or with definite NEC born at Parkland Hospital between 2009 and 2021. A prediction model using the new HASOFA score (Hyperglycemia, Hyperkalemia, use of inotropes for Hypotension during the prior week, Acidemia, Neonatal Sequential Organ Failure Assessment [nSOFA] score) was compared with a similar model using the nSOFA score.

RESULTS

 Among 261 infants, 112 infants had NEC stage I, 68 with NEC stage II, and 81 with NEC stage III based on modified Bell's classification. The primary outcome, surgery for NEC stage III or death within a week, occurred in 81 infants (surgery in 66 infants and death in 38 infants). All infants with pneumoperitoneum or abdominal compartment syndrome either died or had surgery. The HASOFA and the nSOFA scores were evaluated in 254 and 253 infants, respectively, at the time of the initial workup for NEC. Both models were internally validated. The HASOFA model was a better predictor of surgery for NEC stage III or death within a week than the nSOFA model, with greater AUC 0.909 versus 0.825, respectively, p < 0.001. Combining HASOFA at initial assessment with concurrent or later presence of abdominal wall erythema or portal gas improved the prediction surgery for NEC stage III or death with AUC 0.942 or 0.956, respectively.

CONCLUSION

 Using this new internally validated prediction model, surgery for NEC stage III or death within a week can be accurately predicted at the time of initial assessment for NEC.

KEY POINTS

· No available scale, at initial evaluation, accurately predicts which preterm infants will undergo surgery for NEC stage III or die within a week.. · In this retrospective cohort study of 261 preterm infants with either suspected or definite NEC we developed a new prediction model (HASOFA score).. · The HASOFA-model had high discrimination (AUC: 0.909) and excellent calibration and was internally validated..

Analysis of agreement between specialists for the evaluation of radiological findings of necrotizing enterocolitis

OBJECTIVE

The analysis of abdominal radiography is essential for the diagnosis and management of necrotizing enterocolitis (NEC) in newborns (NB). Studies, however, show a lack of agreement among physicians in the interpretation of images. This study aims to evaluate the agreement in the radiological interpretation of the NEC between examiners from different specialties (interexaminer analysis) and between the same examiner at different times (intraexaminer analysis).

METHODS

Cross-sectional study for concordance analysis using plain radiographs of the abdomen of NB with suspected or confirmed NEC. The study included two neonatologists (Neo), two surgeons (SU), and two radiologists (RD). The participants filled out a form with questions about the radiographic findings; regarding the presence of intestinal loop distension, the specialists answered subjectively (yes or no) and objectively (calculation of the ratio between loop diameter and lumbar vertebrae measurements). Kappa coefficients were calculated for agreement analysis.

RESULTS

A total of 90 radiological images were analyzed. For the interexaminer evaluation, the agreement was low (kappa<0.4) in 30 % of the answers (Neo versus SU), 38 % (Neo versus RD), and 46 % (SU versus RD). In the intraexaminer evaluation, the neonatologist and the surgeon presented substantial or almost perfect agreement in 92 % of the answers, and the radiologist in 77 %. In the evaluation of intestinal loop distention, the greatest agreement between the specialties occurred when done objectively.

CONCLUSION

The results confirmed the low intra- and interexaminer agreement in the radiological analysis of the NEC, reinforcing the importance of standardizing the methods of radiological interpretation of the disease.

Clinical Characteristics of Necrotizing Enterocolitis Diagnosed by Independent Adjudication of Abdominal Radiographs, Laparotomy, or Autopsy in Preterm Infants in the "Connection Trial"

OBJECTIVE

 Necrotizing enterocolitis (NEC) classically is diagnosed by radiographic demonstration of pneumatosis intestinalis/portal venous gas (PI/PVG). This study examines clinical characteristics of NEC confirmed by independent evaluation of abdominal radiographs, taken for clinical signs of NEC, or by pathologic findings at laparotomy or autopsy (confirmed NEC [cNEC]).

STUDY DESIGN

 The investigated cohort included 1,382 extremely low birth weight (BW) infants (BW range: 500-1,000 g) with median 27 weeks (range: 23-32) gestational age (GA) at birth. They were randomized into the placebo-controlled "Connection Trial" of the new biological drug candidate IBP-9414 with cNEC as one primary endpoint.

RESULTS

 Total 119 infants (8.6%) had cNEC diagnosed at median 14 days of age by confirming PI/PVG at X-ray adjudication (n = 111) and/or by surgery/autopsy (n = 21). Sixteen percent of cNEC cases died. Adverse events of NEC were reported in 8.5% of infants and 4.1% had NEC diagnosed by radiology and surgery/autopsy at the participating centers. Regression analyses showed that the risk of cNEC decreased by 11 to 30% for every 100-g increment in BW and single-week increment in GA and associated cNEC with odds ratios (ORs) > 2.0 for gastrointestinal (GI) perforation and obstruction, hypotension, hypokalemia, hypophosphatemia, and death. Comparing risks of cNEC in infants below and above 750-g BW showed higher ORs (2.7-4.3) for GI perforation, hypotension, hypokalemia, and renal complications in the smaller infants, whereas the bigger infants had higher ORs (1.9-3.2) for serious non-GI events, late-onset sepsis (LOS), and death. Predictors of cNEC (hazard ratio, HR > 1.5) included serious non-GI events (mainly infections), hyponatremia, and hyperglycemia, whereas the HR was 0.52 for intravenous antibiotics. After cNEC diagnosis, there were higher rates of GI perforation and obstruction, hypotension, hypokalemia, and LOS.

CONCLUSION

 Independent adjudication of abdominal radiographs increased radiological recognition of NEC and proved to be feasible in a multicenter study setting as well as able to diagnose clinically relevant NEC.

KEY POINTS

· Independent adjudication of abdominal radiographs in ELBW infants increased NEC recognition.. · Risk of NEC decreased by 11 to 30% with every 100-g increment in BW and GA week.. · In infants with BW 750 to 1,000 g, the risk of death from NEC was almost twice that in infants with BW 500 to 749 g. · Infants with NEC received antibiotics during one-third and parenteral nutrition during half of the first 7 postnatal weeks..

Impact of fetal inflammatory response on the severity of necrotizing enterocolitis in preterm infants

OBJECTIVE

Neonates born with fetal inflammatory response (FIR) are at increased risk for adverse neonatal outcomes. Our objective was to determine whether FIR and its severity is associated with severity of necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A case-control retrospective study of infants <33 weeks gestational age or <1500 g birthweight, including 260 with stage I-III NEC and 520 controls matched for gestational age. Placental pathology was evaluated, and FIR progression and its severity were defined according to Amsterdam classification.

RESULTS

In this study, mild FIR (i.e., stage 1 FIR) was present in 52 controls (10.0%) and 22 infants with stage I-III NEC (8.5%), while moderate to severe FIR (i.e., ≥stage 2 FIR) was present in 16 controls (3.1%) and 47 infants with stage I-III NEC (18.1%). Both stage and grade of FIR were associated with stage of NEC (P < 0.001). On multinomial logistic regression, stage III NEC was associated with stage of FIR (P < 0.001).

CONCLUSION

This is the first report demonstrating the association between progression and increasing severity of FIR and stage of NEC.

IMPACT

Fetal Inflammatory Response (FIR) and its progression and severity are associated with the stages of necrotizing enterocolitis (NEC). This is the first study demonstrating the impact of progression and severity of FIR on stage III NEC. These observations provide additional insight into understanding the impact of intrauterine exposure to inflammation on the severity of NEC in preterm infants.

Degree of Uncertainty in Reporting Imaging Findings for Necrotizing Enterocolitis: A Secondary Analysis from a Pilot Randomized Diagnostic Trial

Diagnosis of necrotizing enterocolitis (NEC) relies heavily on imaging, but uncertainty in the language used in imaging reports can result in ambiguity, miscommunication, and potential diagnostic errors. To determine the degree of uncertainty in reporting imaging findings for NEC, we conducted a secondary analysis of the data from a previously completed pilot diagnostic randomized controlled trial (2019-2020). The study population comprised sixteen preterm infants with suspected NEC randomized to abdominal radiographs (AXRs) or AXR + bowel ultrasound (BUS). The level of uncertainty was determined using a four-point Likert scale. Overall, we reviewed radiology reports of 113 AXR and 24 BUS from sixteen preterm infants with NEC concern. The BUS reports showed less uncertainty for reporting pneumatosis, portal venous gas, and free air compared to AXR reports (pneumatosis: 1 [1-1.75) vs. 3 [2-3], p < 0.0001; portal venous gas: 1 [1-1] vs. 1 [1-1], p = 0.02; free air: 1 [1-1] vs. 2 [1-3], p < 0.0001). In conclusion, we found that BUS reports have a lower degree of uncertainty in reporting imaging findings of NEC compared to AXR reports. Whether the lower degree of uncertainty of BUS reports positively impacts clinical decision making in infants with possible NEC remains unknown.

Application of comprehensive score of risk factors to determine the best time for surgical intervention in neonatal necrotizing enterocolitis

AIM

Necrotizing enterocolitis (NEC) is a severe digestive systemic disease. Surgery is critical treatment for NEC patients. However, it is still hard to predict the optimal timing of surgery. Our study aimed to explore the indicative effect of comprehensive risk factors method in surgical intervention in NEC patients.

METHODS

Retrospective analysis was made on newborns with NEC, who were divided into group I (patients with NEC conservative therapeutic approach or no necrosis or perforation found in NEC operation) and group II (patients with necrosis or perforation found in NEC operation or failure of NEC conservative approach). Clinical manifestations and complications were recorded and the risk factors scores were calculated. The receiver operating characteristic curve and Youden index were calculated.

RESULTS

One hundred and six NEC patients in Huizhou Central People's hospital were analysed. Significant difference was observed in the comprehensive scores of the two groups to judge the indications of NEC surgery. Among the risk factors of NEC surgery, the incidence specificity of abdominal induration, abdominal tenderness, hypotension and pneumoperitoneum was 100% in group II. The area under the curve of the comprehensive score of risk factors was 0.981 (95% confidence interval 0.958-1.000). The best cutoff value obtained by the maximum Youden index is 3.5 (sensitivity 97.2%; specificity 52.8%). When the specificity is 100%, the best interception value is 7.5 (sensitivity 91.4%; specificity 100%). Complications such as surgical intervention, mortality, stenosis after conservative treatment, perforation or necrosis during surgery were significantly different in different comprehensive scores.

CONCLUSIONS

Abdominal induration, abdominal tenderness, hypotension and pneumoperitoneum are independent predictors of NEC surgery. Comprehensive risk factors score may be a potentially useful clinical decision-making tool for NEC surgery.

Imaging for Diagnosis and Assessment of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is inflammatory bowel necrosis of preterm and critically ill infants. The disease is seen in 6-10% of preterm infants who weigh less than 1500 g at birth and carries considerable morbidity, mortality, and healthcare cost burden. Efforts focused on timely mitigation remain restricted due to challenges in early diagnosis as clinical features, and available laboratory tests remain nonspecific until late in the disease. There is renewed interest in the radiological and sonographic assessment of intestinal diseases due to technological advances making them safe, cost-efficient, and supporting Web-based transmission of images, thereby reducing time to diagnosis by disease experts. Most of our experience has been with plain abdominal radiography, which shows characteristic features such as pneumatosis intestinalis in up to 50-60% of patients. Many patients with advanced disease may also show features such as portal venous gas and pneumoperitoneum. Unfortunately, these features are not seen consistently in patients with early, treatable conditions, and hence, there has been an unfulfilled need for additional imaging modalities. In recent years, abdominal ultrasound (AUS) has emerged as a readily available, noninvasive imaging tool that may be a valuable adjunct to plain radiographs for evaluating NEC. AUS can allow real-time assessment of vascular perfusion, bowel wall thickness, with higher sensitivity in detecting pneumatosis, altered peristalsis, and characteristics of the peritoneal fluid. Several other modalities, such as contrast-enhanced ultrasound (CEUS), magnetic resonance imaging (MRI), and near-infrared spectroscopy (NIRS), are also emerging. In this article, we have reviewed the available imaging options for NEC evaluation.

Clinical significance of positive fecal occult blood test in neonates

The fecal occult blood test (FOBT) is a screening tool for hematochezia. This study aims to summarize the clinical features associated with a positive FOBT in neonates and to explore some clues for the underlying causes. Combination with other clinical information, identifying the possible etiology is more likely and could be useful for choosing an effective therapeutic strategy. The medical records of 282 neonates with positive FOBTs from January 1 to July 31, 2016, were collected and retrospectively analyzed. The total incidence rate of FOBT positivity in neonates was 6.2%. Among these patients, 71 (25.2%) neonates had false-positive FOBTs, whereas 211 (74.8%) neonates had intraintestinal sources of hematochezia. Necrotizing enterocolitis (NEC, 20.9%), structural abnormalities of gastrointestinal tract (SAGT, 12.4%), and suspected food allergy (sFA, 10.6%) were the most common causes of neonatal hematochezia. It indicated that FOBT-positive neonates with NEC were more likely to suffer due to a younger gestational age, lower birth weight, and lower weight on admission than the neonates with other conditions. The proportions of neonates with bloody stool (90.0%) and diarrhea (63.3%) in the sFA group were markedly higher than those in the other groups. However, in the SAGT group, emesis (94.3%) and abdominal distension (80.0%) were evidently higher, usually accompanied by a relatively poor response (60.0%) and weakened bowel sounds (48.6%). Furthermore, the higher incidences of poor response (72.1%), abdominal distension (71.2%), bloody stools (64.4%), and weakened bowel sounds (62.7%) were observed in the NEC group. Due to the complicated etiology associated with a positive FOBT, the analyzed indexes were combined with other clinical features to identify the likely causes of neonatal hematochezia. Because NEC, sFA and SAGT show similar clinical manifestations and can occasionally transform into each other, close and frequent observation is crucial for timely intervention to achieve a better prognosis. Although it failed to provide an early warning of severe disease through FOBT, and the early intervention for FOBT might not decrease NEC, sFA, structural bowel injuries, or any other complications, newborn FOBT positive reminds medical staff to be alert to the related diseases including NEC, SAGT and sFA, by closer observation and follow-up.

Radiographic predictors determined with an objective assessment tool for neonatal patients with necrotizing enterocolitis

OBJECTIVE

The objective of this study was to develop and validate a computational tool to assist radiological decisions on necrotizing enterocolitis.

METHODOLOGY

Patients that exhibited clinical signs and radiographic evidence of Bell's stage 2 or higher were included in the study, resulting in 64 exams. The tool was used to classify localized bowel wall thickening and intestinal pneumatosis using full-width at half-maximum measurements and texture analyses based on wavelet energy decomposition. Radiological findings of suspicious bowel wall thickening and intestinal pneumatosis loops were confirmed by both patient surgery and histopathological analysis. Two experienced radiologists selected an involved bowel and a normal bowel in the same radiography. The full-width at half-maximum and wavelet-based texture feature were then calculated and compared using the Mann-Whitney U test. Specificity, sensibility, positive and negative predictive values were calculated.

RESULTS

The full-width at half-maximum results were significantly different between normal and distended loops (median of 10.30 and 15.13, respectively). Horizontal, vertical, and diagonal wavelet energy measurements were evaluated at eight levels of decomposition. Levels 7 and 8 in the horizontal direction presented significant differences. For level 7, median was 0.034 and 0.088 for normal and intestinal pneumatosis groups, respectively, and for level 8 median was 0.19 and 0.34, respectively.

CONCLUSIONS

The developed tool could detect differences in radiographic findings of bowel wall thickening and IP that are difficult to diagnose, demonstrating the its potential in clinical routine. The tool that was developed in the present study may help physicians to investigate suspicious bowel loops, thereby considerably improving diagnosis and clinical decisions.

Abdominal ultrasound should become part of standard care for early diagnosis and management of necrotising enterocolitis: a narrative review

Necrotising enterocolitis (NEC) is a leading cause of death and disability in preterm newborns. Early diagnosis through non-invasive investigations is a crucial strategy that can significantly improve outcomes. Hence, this review gives particular attention to the emerging role of abdominal ultrasound (AUS) in the early diagnosis of NEC, its performance against abdominal radiograph and the benefits of AUS use in daily practice. AUS has been used in the diagnosis and management of NEC for a couple of decades. However, its first-line use has been minimal, despite growing evidence demonstrating AUS can be a critical tool in the early diagnosis and management of NEC. In 2018, the NEC group of the International Neonatal Consortium recommended using AUS to detect pneumatosis and/or portal air in preterm NEC as part of the 'Two out of three' model. To facilitate widespread adoption, and future improvement in practice and outcomes, collaboration between neonatologists, surgeons and radiologists is needed to generate standard operating procedures and indications for use for AUS. The pace and scale of the benefit generated by use of AUS can be amplified through use of computer-aided detection and artificial intelligence.

Application of abdominal sonography in diagnosis of infants with necrotizing enterocolitis

The purpose of this study was to explore the diagnostic significance of abdominal sonography (AUS) in infants with Necrotizing enterocolitis (NEC) admitted to a neonatal intensive care unit to better evaluate the ability of AUS to differentiate necrotizing enterocolitis from other intestinal diseases.All patients diagnosed with NEC at the Department of General Surgery and Neonatal Surgery, Qilu Children's Hospital between 1st, Jun, 2010 and 30th, Dec, 2015. The logistic regression analysis and the area under receiver operating characteristic (ROC) curve (AUCs) were also used to identify the sonographic factors for diagnosing NEC.For the entire cohort of 91 patients, we divided these patients into suspected NEC (n = 35) group and definite NEC (n = 56) group. After adjusting for competing sonographic factors, we identified that thick bowel wall (more than 2.5 mm) (P = .013, OR: 1.246), intramural gas (pneumatosis intestinalis) (P = .002, OR:1.983), portal venous gas (P = .022, OR:1.655) and reduced peristalsis (P = .011, OR:1.667) were independent diagnostic factors associated with NEC. We built a logistic model to diagnose NEC according to the results of multivariable logistic regression analysis. We found the AUROC for thick bowel wall (more than 2.5 mm), intramural gas (pneumatosis intestinalis), portal venous gas and reduced peristalsis were significantly lower than the AUROC for the logistic model was 0.841 (95% CI: 0.669 to 0.946).We found that thick bowel wall (more than 2.5 mm), intramural gas (pneumatosis intestinalis), portal venous gas and reduced peristalsis were independent diagnostic factors associated with NEC. The logistic model was significantly superior to the single sonographic parameter for diagnosing NEC.

Modifiable Risk Factors in Necrotizing Enterocolitis

Multicenter groups have reported reductions in the incidence of necrotizing enterocolitis (NEC) among preterm infants over the past 2 decades. These large-scale prevalence studies have coincided with reports from multicenter consortia and single centers of modifications in practice using quality-improvement techniques aimed at either reducing NEC risk specifically or reducing risk of mortality and multiple morbidities associated with extreme prematurity. The modifications in practice have been based on mechanistic studies, epidemiologic association data, and clinical trials. Recent reports from centers modifying practice to reduce NEC are reviewed and select modified/modifiable practices discussed.

Pathophysiology of Necrotizing Enterocolitis: An Update

NEC is a devastating disease that, once present, is very difficult to treat. In the absence of an etiologic treatment, preventive measures are required. Advances in decoding the pathophysiology of NEC are being made but a more comprehensive understanding is needed for the targeting of preventative strategies. A better definition of the disease as well as diagnostic criteria are needed to be able to specifically label a disease as NEC. Multiple environmental factors combined with host susceptibility appear to contribute to enhanced risks for developing this disease. Several different proximal pathways are involved, all leading to a common undesired outcome: Intestinal necrosis. The most common form of this disease appears to involve inflammatory pathways that are closely meshed with the intestinal microbiota, where a dysbiosis may result in dysregulated inflammation. The organisms present in the intestinal tract prior to the onset of NEC along with their diversity and functional capabilities are just beginning to be understood. Fulfillment of postulates that support causality for particular microorganisms is needed if bacteriotherapies are to be intelligently applied for the prevention of NEC. Identification of molecular effector pathways that propagate inflammation, understanding of, even incipient role of genetic predisposition and of miRNAs may help solve the puzzle of this disease and may bring the researchers closer to finding a treatment. Despite recent progress, multiple limitations of the current animal models, difficulties related to studies in humans, along with the lack of a "clear" definition will continue to make it a very challenging disease to decipher.

Comparison of abdominal radiographs and sonography in prognostic prediction of infants with necrotizing enterocolitis

PURPOSE

The purpose of this study was to investigate the comparison of AR and AUS in predicting prognosis in infants with necrotizing enterocolitis.

METHODS

All patients were diagnosed as NEC at the department of general surgery and neonatal surgery, Qilu children's hospital between 1st, Jun, 2010 and 30th, Dec, 2016. The logistic regression analysis and the area under ROC curve (AUC)s were also used to compare the prognostic values of radiograph and sonograph for NEC.

RESULTS

Throughout the study period, 86 preterm neonates were hospitalized with diagnosis of definite NEC. Among these patients, 39 infants (45.3%) required surgical treatment. After adjusting for competing sonographic factors, we identified that thick bowel wall (more than 2.5 mm) (p = 0.001, HR: 1.849), intramural gas (pneumatosis intestinalis) (p = 0.017, HR: 1.265), portal venous gas (p = 0.002, HR: 1.824), and reduced peristalsis (p = 0.021, HR: 1.544) were independent prognostic factors associated with NEC. After adjusting for competing radiographic factors, we identified that free peritoneal gas (p = 0.007, HR: 1.472), portal venous gas (p = 0.012, HR: 1.649), and dilatation and elongation (p = 0.025, HR: 1.327). Moreover, we found that the AUROC for AR logistic model was 0.745 (95% CI 0.629-0.812), which was significant lower than the AUS logistic model (AUROC: 0.857, 95% CI 0.802-0.946) for predicting prognosis of NEC.

CONCLUSIONS

In conclusion, we found that several radiographic and sonographic parameters were associated with the prognosis of patients with NEC. The AUS model based on the logistic regression analysis was significant superior to the AR model in the prognostic prediction of NEC.

The role of imaging in the management of necrotising enterocolitis: a multispecialist survey and a review of the literature

Objectives

To investigate current practices and perceptions of imaging in necrotising enterocolitis (NEC) according to involved specialists, put them in the context of current literature, and identify needs for further investigation.

Methods

Two hundred two neonatologists, paediatric surgeons, and radiologists answered a web-based questionnaire about imaging in NEC at their hospitals. The results were descriptively analysed, using proportion estimates with 95% confidence intervals.

Results

There was over 90% agreement on the value of imaging for confirmation of the diagnosis, surveillance, and guidance in decisions on surgery as well as on abdominal radiography as the first-choice modality and the most important radiographic signs. More variation was observed regarding some indications for surgery and the use of some ultrasonographic signs. Fifty-eight per cent stated that ultrasound was used for NEC at their hospital. Examination frequency, often once daily or more but with considerable variations, and projections used in AR were usually decided individually rather than according to fixed schedules. Predicting the need of surgery was regarded more important than formal staging.

Conclusion

Despite great agreement on the purposes of imaging in NEC and the most important radiographic signs of the disease, there was considerable diversity in routines, especially regarding examination frequency and the use of ultrasound. Apart from continuing validation of ultrasound, important objectives for future studies include definition of the supplementary roles of both imaging modalities in relation to other diagnostic parameters and evaluation of various imaging routines in relation to timing of surgery, complications, and mortality rate.

Key Points

• Imaging is an indispensable tool in the management of necrotising enterocolitis

• Predicting the need of surgery is regarded more important than formal staging

• There is great consensus on important signs of NEC on abdominal radiography

• There is more uncertainty regarding the role of ultrasound

• Individualised management is preferred over standardised diagnostic algorithms

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5362-x) contains supplementary material, which is available to authorized users.

Diagnostic imaging features of necrotizing enterocolitis: a narrative review

Necrotizing enterocolitis (NEC) is an inflammatory process, characterized by intestinal necrosis of variable extension, leading to perforation, generalized peritonitis and death. The classical pathogenetic theory focuses on mucosal damage related to a stress induced intestinal ischemia leading to mucosal injury and bacterial colonization of the wall. A more recent hypothesis emphasizes the role of immaturity of gastrointestinal and immune system, particularly of the premature, responsible of bowel wall vulnerability and suffering. NEC is the most common gastrointestinal emergency in the newborn, with a higher incidence in the preterm; improvement of neonatal resuscitation techniques enables the survival of premature of very low birth weight (VLBW) with prolongation of hospital stay for perinatal and neonatal care and a higher risk of NEC. Clinical presentation of NEC in newborn ranges from mild forms with moderate gastrointestinal tract disorder and that can heal spontaneously, to very serious forms with fulminant course characterized by perforation, peritonitis, sepsis, disseminated intravascular coagulation (DIC) and shock. Imaging modality in the diagnosis of NEC is historically represented by the plain-film abdominal radiographs which can be performed every 6 hours because of the rapid evolution that may occur in the patient's clinical condition. However ultrasound (US), in recent years, is playing an increasingly important role in the evaluation of early stages of the disease as it provides images in real time of the abdominal structures being able to assess the presence and validity of peristalsis of the bowel loops, detect the thickness of the intestinal wall and the presence of minimal amounts of fluid in the peritoneal cavity. In this paper we review the pathogenesis, clinical presentation and imaging of NEC with a particular attention to the emergent role of US in the diagnosis of the disease.

Agreement and reproducibility of radiological signs in NEC using The Duke Abdominal Assessment Scale (DAAS)

PURPOSE

Necrotizing enterocolitis (NEC) is associated with high morbidity and mortality. Abdominal radiography is currently an imaging modality of choice in NEC. Recently, a numeric scale of radiological signs in NEC-The Duke Abdominal Assessment (DAAS) was introduced. The aim of this study was to measure the intra- and inter-observer agreement on the radiological signs of NEC according to DAAS to access the feasibility of this scale.

MATERIALS AND METHODS

We have retrospectively analyzed 87 radiographs performed in a group of 43 high-risk neonates with suspected NEC. Radiographs were assessed by 6 independent observers: two pediatric radiologists, two radiology residents, and two neonatologists. Data were analyzed using κ statistics as a measure of intra- and inter-observer agreement.

RESULTS

Fair-to-good intra-observer agreement was noted for all but one of observers. However, with the wide range in κ values, we found only fair inter-observer agreement detecting signs of NEC according to DAAS. There was a higher intra-group agreement in radiology practitioners, with the highest among experienced pediatric radiologists.

CONCLUSION

However, with high observer variability in interpretation of all radiologic signs, we did not confirm that Duke Abdominal Assessment Scale could reliable facilitate reporting of abdominal radiographic findings in neonates with suspected NEC.

Ultrasonography and radiography findings predicted the need for surgery in patients with necrotising enterocolitis without pneumoperitoneum

AIM

The timing of surgical intervention in patients with necrotising enterocolitis (NEC) without pneumoperitoneum remains unclear. This study aimed to identify the predictors associated with surgical intervention in such patients and to assess how effective imaging reports were as an aid to surgical decision-making.

METHODS

We collected clinical data, laboratory investigations and imaging findings on NEC patients without pneumoperitoneum. A critical imaging report was defined as persistent dilation of bowel loops and evidence of portal venous gas on radiography and thickening of the bowel wall, absent peristalsis and evidence of echogenic-free fluid on sonography. Independent predictors of surgical NEC were identified using multivariate logistic regression analysis. Sensitivity and specificity analyses were performed for the imaging findings, and receiver operator characteristic curve analysis was used to evaluate the predictive accuracy.

RESULTS

Of the 238 neonates studied, 54 (22.69%) required surgical intervention. The multivariate logistic regression analysis showed that abdominal erythema, C-reactive protein levels and the critical imaging report were independent predictors of the need for surgical intervention. The critical imaging report was the most powerful predictor of surgical NEC.

CONCLUSION

Both ultrasonography and radiography findings proved helpful in predicting the need for surgery in NEC without pneumoperitoneum.

Acute drop in blood monocyte count differentiates NEC from other causes of feeding intolerance

OBJECTIVE

Necrotizing enterocolitis (NEC) is characterized by macrophage infiltration into affected tissues. Because intestinal macrophages are derived from recruitment and in situ differentiation of blood monocytes in the gut mucosa, we hypothesized that increased recruitment of monocytes to the intestine during NEC reduces the blood monocyte concentration and that this fall in blood monocytes can be a useful biomarker for NEC.

STUDY DESIGN

We reviewed medical records of very-low-birth-weight (VLBW) infants treated for NEC and compared them with a matched control group comprised of infants with feeding intolerance but no signs of NEC. Clinical characteristics and absolute monocyte counts (AMCs) were recorded. Diagnostic accuracy of AMC values was tested using receiver-operator characteristics (ROC).

RESULT

We compared 69 cases and 257 controls (median 27 weeks, range 26 to 29 in both the groups). In stage II NEC, AMCs decreased from median 1.7 × 10(9) l(-1) (interquartile range (IQR) 0.98 to 2.4) to 0.8 (IQR 0.62 to 2.1); P < 0.05. In stage III NEC, monocyte counts decreased from median 2.1 × 10(9) l(-1) (IQR 0.1.5 to 3.2) to 0.8 (IQR 0.6 to 1.9); P < 0.05. There was no change in AMCs in control infants. ROC of AMC values showed a diagnostic accuracy (area under the curve) of 0.76. In a given infant with feeding intolerance, a drop in AMCs of > 20% indicated NEC with sensitivity of 0.70 (95% confidence interval (CI) 0.57 to 0.81) and specificity of 0.71 (95% CI 0.64 to 0.77).

CONCLUSION

We have identified a fall in blood monocyte concentration as a novel biomarker for NEC in VLBW infants.

Predicting disease severity of necrotizing enterocolitis: how to identify infants for future novel therapies

Necrotizing enterocolitis (NEC) remains a very devastating problem within the very low birth weight neonatal population. Several experimental therapies are being tested in animal models and soon may be ready for human trials. Despite this progress, we currently have no way to identify infants who would be optimal targets for therapy. Specifically, we are unable to predict which infants will progress to the more severe Bell's stage of disease that may necessitate surgery. Ideally, an algorithm could be constructed that would encompass multiple neonatal and maternal risk factors as well as potential biologic markers of disease so that these infants could be identified in a more timely fashion. This review summarizes the known risk factors and biomarkers of disease in hopes of stimulating clinical research to identify such an “early warning” NEC algorithm.

Inter-rater agreement in the evaluation of abdominal radiographs for necrotizing enterocolitis

PURPOSE

Abdominal radiographs are frequently employed in the surveillance of patients with necrotizing enterocolitis (NEC), with typical findings well described. Clinicians interpret and act upon these films at different intervals, however, and inter-rater agreement has not been evaluated to date.

METHODS

Thirty abdominal radiographs of premature infants were distributed to attending radiologists (4), pediatric surgeons (4), and trainees (4), who evaluated for findings of NEC from a list of eight potential choices (1=normal, 8=perforation). Fleiss's Kappa (FK) was used to evaluate concordance between multiple raters with 0-0.2=slight association and 0.8-1=almost perfect agreement.

RESULTS

Practicing surgeons had an FK of 0.77 overall (95% CI: 0.67-0.87), but demonstrated poor agreement when evaluating decubitus films (FK: 0.39, 95% CI:0.12-0.65). Radiologists had excellent inter-rater agreement (FK: 0.81, 95% CI: 0.74-0.88), but had only modest agreement with surgeons (FK: 0.59, 95% CI: 0.56-0.63) and poor agreement for decubitus films (FK: 0.15, 95% CI: 0.47-0.26). Surgical and radiology trainees had fair agreement with their respective attendings (0.60, 95% CI: 0.55-0.65 and 0.64, 95% CI: 0.60-0.69, respectively).

CONCLUSIONS

While inter-rater agreement was good-excellent among attending staff, it was only moderate between radiologists and surgeons and between trainees and their attendings. This highlights the importance of inter-disciplinary and hierarchical communication to optimize clinical decision-making. Decubitus films may be of limited value in evaluating patients with NEC.

Cohort study of probiotics in a North American neonatal intensive care unit

OBJECTIVE

To determine whether routine probiotic administration to very preterm infants would reduce the incidence of necrotizing enterocolitis (NEC) without adverse consequences.

STUDY DESIGN

Since the end of July 2011, we have administered a probiotic mixture to all admitted infants of <32 weeks' gestation. We give 0.5 g of a mixture of 4 bifidobacteria (Bifidobacterium breve, bifidum, infantis, and longum) and Lactobacillus rhamnosus HA-111 [corrected] (2 × 10(9) colony-forming units) per day, starting with the first feed, until the infant reaches 34 weeks. We compared complications among infants admitted during the first 17 months of routine use with those admitted during the previous 17 months.

RESULTS

Two hundred ninety-four infants received probiotics, and 317 infants formed the comparison group. Introduction of probiotics was associated with a reduction in NEC (from 9.8% to 5.4%, P < .02), a nonsignificant decrease in death (9.8% to 6.8%), and a significant reduction in the combined outcome of death or NEC (from 17% to 10.5%, P < .05). After adjustment for gestational age, intrauterine growth restriction, and sex, the improvements remained significant (OR for NEC, 0.51; 95% CI, 0.26-0.98; OR for death or NEC, 0.56; 95% CI, 0.33-0.93). There was no effect of probiotics on health care-associated infection.

DISCUSSION

A product that is readily available in North America, that has excellent quality control, and that contains strains similar to those that have been shown effective in randomized controlled trials substantially reduced the frequency of NEC in our neonatal intensive care unit.

A prospective comparison of intestinal sonography and abdominal radiographs in a neonatal intensive care unit

BACKGROUND

No study reported in the literature comprehensively compares findings on neonatal abdominal radiographs with sonography.

OBJECTIVE

To compare the findings on abdominal radiographs and sonograms in infants in intensive care, to better understand how the various intestinal gas patterns on radiographs relate to the spectrum of appearances on sonography and, second, to evaluate the ability of sonography to differentiate necrotizing enterocolitis from other intestinal pathology.

MATERIALS AND METHODS

We prospectively evaluated sonograms and radiographs, blinded to the other modality and to clinical information. Patients' charts were reviewed by a third blinded reader and used as a reference standard for diagnosis. We made associations between sonographic findings, radiographic intestinal gas patterns and clinical diagnoses.

RESULTS

We included 75 infants with gestational ages between 23 weeks and 41 weeks. Sonographic abnormalities were present in infants with all radiographic intestinal gas patterns, including normal patterns. We only saw absent intestinal perfusion and fluid collections on sonography (suggesting intestinal necrosis and sealed perforation) in infants with intestinal dilatation with elongation on radiographs. Separation of intestinal loops on radiographs was most commonly caused by reasons other than intestinal wall thickening. Increased intestinal echogenicity or free fluid with echoes on sonography correlated with a diagnosis of necrotizing enterocolitis, whereas anechoic free fluid correlated with absence of necrotizing enterocolitis.

CONCLUSION

Sonography is complementary to radiographs in infants with suspected intestinal pathology, with a spectrum of appearances seen on each modality. Some sonographic findings either strongly suggest necrotizing enterocolitis or supply evidence against this diagnosis.

The Duke Abdominal Assessment Scale: initial experience

Plain abdominal radiographs are the current standard imaging modality of choice in the evaluation of patients with clinically suspected necrotizing enterocolitis. The time interval between radiographic exams varies with the severity of disease and may range from every 6 h to every 24 h. Radiographs are often also obtained at any point of acute clinical deterioration. Evaluation of the abdominal radiographic series is critical as the findings may alter patient management and can be an indication for surgical intervention. For these reasons, it is essential that the radiographic findings are communicated to the referring neonatologist in a clear and consistent manner. Inherent variability and lack of consistency in radiology reporting makes it difficult for the referring clinician to incorporate radiographic reports into his/her treatment algorithm. Assigning abdominal radiographic findings in necrotizing enterocolitis to a numerical scale that increases as the disease progresses provides objective terminology in lieu of subjective descriptors and may facilitate communication to our clinical colleagues. With this task in mind, the Duke Abdominal Assessment Scale was created as a 10-point numerical scale of plain film bowel gas pattern findings designed to reflect progressive disease and increased certainty of the diagnosis of necrotizing enterocolitis.

Radiographic predictors of disease severity in neonates and infants with necrotizing enterocolitis

OBJECTIVE

The objective of our study was to validate a radiographic scale, the Duke abdominal assessment scale (DAAS), as a tool for predicting the severity of disease in neonates and infants with suspected necrotizing enterocolitis (NEC).

MATERIALS AND METHODS

Study group patients (n = 43) underwent at least two two-view abdominal radiographic series within 48 hours of surgical intervention for suspected NEC complications. Control group patients (n = 86) were patients with suspected NEC who did not undergo surgery for suspected NEC complications. DAAS scores were assigned by two pediatric radiologists with 20 and 6 years' experience.

RESULTS

The initial radiographs of 26 of 43 (60.5%) patients in the study group showed fixed bowel loops (10/43, 23.3%), highly probable or definite pneumatosis (9/43, 20.9%), or portal venous gas (7/43, 16.3%). These findings had progressed to pneumoperitoneum on the follow-up series in 20 (46.5%) study group patients. Among the control group, three patients (3.5%) had highly probable or definite pneumatosis, and none had fixed bowel loops, portal venous gas, or pneumoperitoneum. Patients with higher DAAS scores were more likely to undergo surgical intervention than patients with lower scores (odds ratio, 1.69; 95% CI, 1.40-2.03). A receiver operating characteristic curve analysis showed good overall performance (c statistic = 0.83) for predicting eventual surgical intervention in the study group with higher DAAS scores.

CONCLUSION

The DAAS provides a standardized 10-point radiographic scale that increases with disease severity when using need for surgical intervention as a surrogate for severe NEC. For every 1-point increase in the DAAS score, patients were statistically significantly more likely to have severe disease as measured by need for surgical intervention.