When were your sputum cultures done? You had at least three done, each a week apart, and two were positive? If the sputum samples were 7 months ago like your last CT I myself would want to repeat them. I have read that you can have MAC without lung damage and I believe I have read some members here comment on having little to no damage on CT. But given the symptoms you are describing, to a novice like myself, that seems curious, and I understand your confusion. I am asymptomatic but my CT’s show quite a bit of damage. And that seems strange to me also. My infection disease doctor says it’s like back pain - the CT is not an accurate barometer for clinical symptoms. Hopefully you can find an NTM expert near you to guide you on this confusing and challenging path.