8. Why is ultrasound used to investigate congenital hypertrophic pyloric stenosis? Posted on April 19, 2023 Correct answer: Ultrasound scan demonstrates the thickened pylorus and large stomach. Post navigation Previous Post7. What special investigations would you use to investigate congenital hypertrophic pyloric stenosis? Next Post9. Why is abdominal X-ray used to investigate congenital hypertrophic pyloric stenosis?