Pulmonary speckle foci refer to the phenomenon of speckled shadows in the lungs with a higher density than the surrounding normal cellular tissue during the medical imaging process. Because the interstitial tissue of the lung is affected by the disease and has organ damage, after effective treatment, the organism secretes collagen and other proteins to heal the damage due to the self-repair mechanism, which results in the appearance of speckled foci. It may also be a symptom of lung lesions, as the lesions may cause localized nodules in the interstitial lung tissue or fibrosis in the lung, resulting in the appearance of dotted high-density shadow.