A 2-year-old boy admitted to the hospital complaining of wheezing and shortness of breath for 6 weeks. At the beginning, the mother claimed that she noticed her baby had chocking one time. There was no cough, no fever. He was treated with inhaled corticosteroids but with no improvement. No history of allergy and no family history of atopic dermatitis. On day of admission, Chest x ray was normal and leukocyte number was normal. Note: (think about the neck region only)

What is the next step of radiological investigation should be done for this patient?
What is the anatomical structure you should think to be involved in this patient?
What is the suspected diagnosis in this case?
What is the appropriate management in this case?
What in your opinion is the most important point must the physician always keep in mind?​