The possible clinical causes of 8mm striated shadow in the lungs include old tuberculosis, pneumonia, interstitial fibrosis, etc. 1. Old tuberculosis: this is the most common cause of the above situation, after regular anti-tuberculosis treatment, people with the disease will often leave old calcified foci, and lung imaging can find streaks. 2. Pneumonia: some people with this disease have poor recovery ability, the inflammatory lesions can not be completely absorbed and left with fibrous streaks. 3. Interstitial fibrosis: the presence of striated shadows in the lungs usually suggests that the people with the disease have fibrous connective tissue hyperplasia in the lungs, so it may be interstitial fibrosis caused by related diseases, which can either show focal distribution or diffuse distribution. It is recommended that people with this condition should go to the hospital for examination to make a clear diagnosis, so as to carry out targeted treatment.