I am a 23 year old guy. I recently had a master health checkup done. Everything was ok except for a fact that my chest xray indicated that I had prominent left hilum. The doctor who I consulted that there is nothing to worry in 99% of the cases but I should be careful and take a CT scan done. Is it necessary or should I go for an MRI? Do I need to worry? P.S I have had asthma and weezing as a child and I had primary complex twice in my childhood. I have been smoking for the last 4 years.