Bowel Ultrasound for the Diagnosis of Necrotizing Enterocolitis

Abstract

Radiographic evaluation for necrotizing enterocolitis (NEC) often yields nonspecific findings. Bowel ultrasound (BUS) provides additional information beyond that of abdominal radiographs and may be helpful in the diagnosis of NEC in neonates. We systematically reviewed and aggregated existing literature to get a better estimate of diagnostic accuracy of BUS in the diagnosis of NEC. A literature search was performed using PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature to identify studies in which infants with clinically suspected NEC were evaluated using BUS. Studies that used modified Bell staging criteria as the reference standard were included. Study quality was assessed, and pooled sensitivity and specificity of various BUS findings for diagnosing NEC were determined. Six articles with a total of 462 patients met eligibility and inclusion criteria. There was heterogeneity in BUS findings evaluated across studies. Ultrasound detection of classic signs of NEC (portal venous gas, pneumatosis, and free air) had pooled sensitivities ranging from 0.27 to 0.48 and pooled specificities ranging from 0.91 to 0.99. Bowel wall thinning and absent peristalsis had overall low sensitivity (0.22 and 0.30) but high specificity (0.96 and 0.96) for NEC. Assessment of abdominal fluid, which included ascites and focal fluid collection, also had overall low sensitivity and high specificity (simple ascites: 0.45 and 0.92; focal fluid collection: 0.19 and 0.98). In summary, individual BUS findings have low sensitivity and high specificity for diagnosis of NEC. Bowel ultrasound may be a useful adjunct to plain abdominal radiographs in the evaluation of infants with clinical suspicion of NEC.

Portal venous gas by ultrasound in advance of impending necrotizing enterocolitis of a very low birth weight infant

“…Compared with X‐ray, the advantage of ultrasound in sensitivity and specificity of PVG has been proved, which indicates that ultrasound can differentiate NEC with other neonatal intestinal diseases effectively . For this patient, although clinical manifestations, the initial lab test and X‐ray were all negative, we still gave fasting, antiinfection and other treatment in view of these research, which verified the value of ultrasound in detection of PVG and the performance of differentiating NEC from other neonatal intestinal diseases, the ensuing routine stool, X‐ray examinations and clinical course confirmed our judgment.…”

Use of ultrasound findings to predict bowel ischemic changes in pediatric patients with intestinal volvulus

“…Therefore, ascites due to volvulus may be difficult to differentiate from physiologic ascites. However, echogenic ascites is an important indicator for surgical interventions in neonates with necrotizing enterocolitis . In our limited study cohort, although this finding was associated with bowel resection but not with bowel ischemia, the 2 cases with echogenic ascites had bowel ischemia and needed bowel resection.…”

“…Various imaging findings have been reported as predictors of intestinal disorders . On the basis of these previous findings, we reviewed the following US findings: (1) superior mesenteric artery collapse (Figures ); (2) ascites (Figure ); (3) echogenic ascites (Figure ); (4) portal venous gas; and (5) free air.…”

“…Portal venous gas and pneumatosis intestinalis were detected in patients with various underlying diseases such as life‐threatening conditions including intestinal necrosis as well as non–life‐threatening conditions including food allergies, constipation, and drug‐induced effects . Furthermore, free air was reported to be a predictor of a worse prognosis in patients with intestinal necrosis . Although computed tomography is usually performed in adult patients with suspected bowel necrosis, ultrasound (US) imaging is a useful examination that can be conducted at a patient's bedside and is usually the first examination for pediatric patients with suspected volvulus …”

“…3 Various imaging findings, such as portal venous gas, pneumatosis intestinalis, free air, and ascites, have been used to Video online at jultrasoundmed.org diagnose intestinal volvulus and necrosis. [6][7][8][9] Portal venous gas and pneumatosis intestinalis were detected in patients with various underlying diseases such as life-threatening conditions including intestinal necrosis as well as non-life-threatening conditions including food allergies, constipation, and druginduced effects. 6,7,[10][11][12] Furthermore, free air was reported to be a predictor of a worse prognosis in patients with intestinal necrosis.…”