4. Evaluate for the presence of radiodensities such as calcifications and air fluid levels. If these exist, calcifications within or around the bowel will be seen as white masses and a bowel filled with fluid will cast vague and confluent gray shadows. Calcifications may be caused by sterile meconium peritonitis, which appears as small, rounded opacities; renal calculi; teratomas that are retroperitoneal; or neuroblastoma.