First, let's talk about the reading and interpretation of CT scans. When a CT scan is ordered, the doctor explains what they are looking for, you make an appointment and the tech performs the scan.

A radiologist reads the scan and reports the findings back to the doctor; concentrating on the reason for the order, other items found are reported as "incidental findings." Depending on the orders, the report may be text only, text with relevant slides, or text with the entire CT file.
Here is an interesting description of one radiologist's way of reading images:
https://www.neighborhoodradiologist.com/how-i-read-imaging-studies/
The ordering doctor reads the report/views the scan (and may consult further with the radiologist, a colleague or a specialist) then interprets it to you. You may then be told all is well, or you may be referred to a specialist.

Why see a pulmonologist? As a generalist, your doctor "knows a little about a lot of things", but as a specialist the pulmonologist "knows a lot about some specific things." They have at least 6000 hours of additional training, and day-to-day experience adds thousands more hours to their personal knowledge database.

My pulmonologist re-reads all CTs and interprets them based on her knowledge and experience. She often shows me specific images noted by the radiologist and explains why they are or are not significant in my case. I would not suggest that she submit my CT scan to a third party, she would know to do it herself if she had questions.

So, I would meet with the pulmonologist. Here are some questions I might ask -
-Why is there a difference between the CT findings?
-If you recommend additional imaging, how does it differ from what is already done?
-What specifically does the nodule suggest at this point (based on size, shape, location, appearance of total lung, your medical history) based on your education and experience?
-Is this of immediate concern, and if so, what is the next step?
-If not, do we follow up to see if the nodule changes? How often?

Does this help you in planning your visit? When is the appointment?