Intramural bowel gas and portal venous gas
Intramural gas in the bowel wall is an imaging sign, rather than a diagnosis. This entity can result from various pathologic processes in the neonatal period including prematurity, necrotizing enterocolitis, hypoplastic left or right heart syndrome, bowel obstruction, Hirschsprung disease and gastrointestinal Rotavirus.
Plain abdominal radiography and ultrasonography are the mainstays of imaging workup. A vertical beam and a horizontal beam radiography with the patient being in the supine position are necessary for diagnosis.
Portal venous gas appears as branching (lucencies on radiograph and echogenicity on ultrasonography) extending toward the periphery of the liver. The advantage of ultrasound over radiograph is real time ability for depicting bowel mural thickness, echogenicity, peristalsis, mural gas, perfusion and intraperitoneal fluid.
With appropriate clinical history, the radiologist can play an important role in the detection of pneumatosis intestinalis, differentiation of its medical and surgical causes and finally suggesting appropriate treatment approach.