Which diagnostic test is both diagnostic and therapeutic for intussusception?

Choice A reason: Barium or air enema is both diagnostic and therapeutic for intussusception. It visualizes the telescoped bowel segment (diagnostic) and applies pressure to reduce the invagination (therapeutic), resolving most cases non-surgically. This dual role makes it the standard approach, aligning with the correct answer. Choice B reason: Abdominal x-ray can suggest intussusception by showing air-fluid levels or obstruction but is not therapeutic. It lacks the specificity to confirm the diagnosis and cannot reduce the telescoped bowel, making it an incorrect choice for a test that serves both diagnostic and therapeutic purposes. Choice C reason: Abdominal ultrasound is highly sensitive for diagnosing intussusception, showing the “target sign” of telescoped bowel. However, it is not therapeutic, as it cannot reduce the invagination. It is used for confirmation, not treatment, making it incorrect for a dual-purpose test in this context. Choice D reason: CT scans can diagnose intussusception by visualizing bowel obstruction but are not therapeutic. They involve radiation exposure, making them less preferred in children, and do not reduce the telescoped bowel, making this an incorrect choice for a test with both diagnostic and therapeutic roles.