Necrotizing Enterocolitis: Review of State-of-the-Art Imaging Findings with Pathologic Correlation

Abstract

Plain abdominal radiography is the current standard imaging modality for evaluation of necrotizing enterocolitis (NEC). Sonography is still not routinely used for diagnosis and follow-up, as it is not widely recognized that it can provide information that is not provided by plain abdominal radiography and that may affect the management of NEC. Like plain abdominal radiography, sonography can depict intramural gas, portal venous gas, and free intraperitoneal gas. However, the major advantages of abdominal sonography over plain abdominal radiography are that it can depict intraabdominal fluid, bowel wall thickness, and bowel wall perfusion. Sonography may depict changes consistent with NEC when the plain abdominal radiographic findings are nonspecific and inconclusive. Thinning of the bowel wall and lack of perfusion at sonography are highly suggestive of nonviable bowel and may be seen before visualization of pneumoperitoneum at plain abdominal radiography. The mortality rate is higher after perforation; thus, earlier detection of severely ischemic or necrotic bowel loops, before perforation occurs, could potentially improve the morbidity and mortality in NEC. The information provided by sonography allows a more complete understanding of the state of the bowel in patients with NEC and may thus make management decisions easier and potentially change outcome.

Monitoring technologies in the neonatal intensive care unit: implications for the detection of necrotizing enterocolitis

“…14 In NEC, inflammation causes initial hyperemia in the bowel wall, which is followed by ischemia and bowel wall thinning. This progression of NEC, which was confirmed by color Doppler U/S evidence, 13 is illustrated in Figure 3. …”

“…Color Doppler U/S may be useful in determining bowel viability, which can be characterized by bowel wall thickness and perfusion. 13,14 Determining the viability by differentiating ischemic from necrotic bowel is not possible using the current radiographic method. Color Doppler detection of absent blood flow showed 100% sensitivity, which is far greater than that of radiographic detection of peritoneal free air (40%) as a positive sign for severe NEC with necrotic bowel (P ¼ 0.3).…”

Ultrasound in newborns and children suffering from non-traumatic acute abdominal pain: imaging with clinical and surgical correlation

“…Clinical signs and symptoms include: abdominal distension, hematochezia, apnea, acidosis, temperature instability and lethargy. Plain abdominal radiography is still the current modality of choice for the evaluation of neonates suspected of having NEC [13].…”

Technical aspects of abdominal ultrasound and color Doppler assessment of bowel viability in necrotizing enterocolitis

“…The diagnosis of NEC might be delayed at times because the early signs are nonspecific [2][3][4][5]. The prognosis of NEC worsens with perforation, and mortality rates range from 15% to 30% [2][3][4].Abdominal radiography is the standard modality for diagnosis, monitoring and guiding management in NEC. The use of abdominal US in NEC has been described in publications since the 1980s and 1990s [6][7][8][9].…”

“…The prevalence is approximately 1-5% of admissions in the NICU [2][3][4]. NEC manifests in the first 2 weeks after birth or later [2].…”