CT Diagnosis of Diffuse Pulmonary Nodules —— Distribution Types (I)

Perilymphatic distribution: Nodules are caused by lymphangiopathy, mainly distributed in and around lymphatic vessels, including peribronchovascular bundle, lobular center, interlobular septum and subpleural area, and are common in sarcoidosis, carcinomatous lymphangitis, pneumoconiosis or silicosis.

Distribution in the center of lobule: Nodules are confined in the center of lobule, not connected with interlobular septum and pleura, but at a certain distance from them, generally 5 ~ 10 mm away from pleural surface in the periphery of lung. Nodules are common in pathological changes caused by airway inhalation, such as allergic pneumonia, disseminated pulmonary tuberculosis, diffuse bronchiolitis and pneumoconiosis. According to the shape of pulmonary nodules, they can be divided into tree bud type and tree bud type.

Encyclopedia of radiology

Nodules with tree bud sign are small airway nodules.

Nodules without tree bud sign mainly include interstitial nodules and air cavity nodules.

Tree bud sign-small airway nodule

CT findings are nodular and short-line images with a diameter of 3 ~ 5 mm, which are connected with bronchial vascular bundles and resemble branching buds, which is called "tree bud sign".

Mainly seen in small airway lesions, its pathological basis is that bronchioles and distal small airways are filled with mucus or inflammatory secretions.

It is found in many inflammatory diseases, such as disseminated pulmonary tuberculosis, diffuse bronchiolitis and infectious bronchiolitis.

No tree bud sign-cavitation nodule

CT showed ground glass density nodules with blurred edges and located in the center of lobules.

The pathological basis of air cavity nodules is consolidation of air cavity around bronchioles, which is common in all kinds of inflammation, bleeding and edema.

Common air cavity sarcoidosis becomes allergic pneumonia, eosinophilic granuloma and so on.

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