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Bronchiectasis, Industrial and Interstitial Lung Diseases

  1. Radiographic features of Bronchiectasis: Q
    1. ‘Bunch of grapes’ appearance
    2. ‘Gloved fingered’ appearance
    3. ‘Ring’ shadows
    4. ‘Tram track’ appearance

‘Signet-ring’ sign on HRCT lung is diagnostic sign of bronchiectasis.

  1. Asbestosis
    1. Pleural changes:
      1. Commonest radiological feature of asbestos exposure is the pleural plaque, which is well-defined soft tissue sheet originating on the parietal pleural. The extent of the plaques is related to the severity of exposure.
      2. There is a latent period of over 10 years between exposure and plaque
      3. development, and calcification within the plaques is rarely seen less than 20 years after exposure.
      4. Diffuse pleural thickening
      5. Pleural effusions
      6. Malignant mesothelioma

The lesions are usually bilateral, lying in middle and lower zones and over the diaphragm. When calcified they form a 'holly leaf' pattern with sharp, often angulated outlines.

  1. Pulmonary changes:
    1. The radiological features are similar to those of fibrosing alveolitis.
    2. Unlike CWP, UZ are spared even in smokers (100 times the rate in nonsmokers).
    3. Pulmonary pseudotumor can be a feature, which characteristically shows distortion of pulmonary vasculature producing a ‘Comet tail’ appearance on plain x-ray, and CT.
    4. ‘Comet tail’ appearance is also seen in Round atelectesis.Q
    5. Extrathoracic changes: Peritoneal mesothelioma and laryngeal carcinoma.

  1. Lung Neoplasms
    1. Pulmonary hamartomas
      1. These are benign lung neoplasms with average age of presentation being 40–45 years.
      2. They consist of masses of cartilage with clefts lined by bronchial epithelium, which may contain large collections of fat.
      3. Malignant transformations are either non-existent/extremely rare.
      4. QCarney's triad:
        1. Pulmonary chondromas
        2. Gastric leiomyosarcoma
        3. Extraadrenal paragangliomas
      5. CXR: Spherical or slightly lobulated well-defined nodule (< 4 cm size) with normal surrounding lung, Q'irregular/popcorn' calcification and frequency of calcification increases with the size of lesion.
      6. CT: Popcorn calcification is virtually diagnostic (only DD is a Chondrosarcoma) and central fat density if present also establishes the diagnosis.
    2. Solitary Pulmonary Nodule
      1. A solitary pulmonary nodule is any pulmonary or pleural sharply defined discrete nearly circular radio-opacity of < 3 cm but > 2 cm diameter.
      2. It is called mass when the diameter exceeds 3 cm. Q

Characterization of SPN: Q





< 2 cm

>3 cm

Doubling time

Longer (18 months)

1–6 months


Smooth, well defined

Irregular, spiculated or notched


Sharply marginated



Thin, smooth walled

Thick, irregular walled


Central, solid, laminated 'popcorn' like (hamartoma)rarely punctate

Peripheral, diffuse, amorphous,

Fat (intranodular)

Seen in hamartoma-

Internal attenuation


Bubble like areas of low attenuation.
Bronchoalveolar carcinoma and lymphoma show significant
enhancement on CECT.

Satellite lesions

99% inflammatory lesions Only 1%
show it (TB)

Bone destruction



Causes of calcifying malignant lung lesions include: Q
  1. Carcinoid (33%),
  2. Lung cancer (6%),
  3. Metastases from chondrosarcoma and
  4. Mucinous adenocarcinoma metastases.

QPET is non-invasive method to distinguish benign from malignant focal pulmonary abnormalities. It can provide biochemical information about lesions that are indeterminate by conventional imaging methods. 18F-2-deoxy-D-glucose (FDG), a D-glucose analogue, is the most commonly used radionuclide. Increased glucose metabolism by malignant lesions results in increased uptake, trapping and accumulation of FDG, which permits differentiation from most benign abnormalities. It accurately excludes malignancy in pulmonary nodules as small as 1 cm.

  1. Lung Cancer
    1. Small cell tumors of Lung have the fastest rate of growth, usually disseminate at the time of presentation, are usually central and are typically associated with mediastinal and hilar adenopathy, but rarely cavitate while non-small cell tumors, especially the adenocarcinomas usually arise peripherally, sometimes in fibrotic lung and cavitate less often but Squamous cell carcinoma arise centrally, gross relatively slowly and cavitate often.
    2. Small cell carcinoma of the lung is a more common cause of paraneoplastic syndromes, particularly the Eaton Lambert syndrome of myasthenic myopathy and hypercortisolism due to ectopic ACTH production. Q
    3. A peripheral pulmonary mass on chest X-ray is a common presentation of lung cancer.
    4. Few features can also differentiate between a benign and a malignant pulmonary nodule.
    5. Malignant tumors are usually larger at the time of presentation, have poorly defined, lobulated, spiculated or umbilicated margins, may cavitate with thick walls with irregular nodular inner margin, may have associated bone destruction and asymmetrical pleural thickening.
    6. Benign lesion like folded lung or diffuse calcification in a nodule can be easily diagnosed on CT thus excluding malignancy.
  1. Pancoast/superior sulcus Tumor
    1. It includes:
      1. Bronchogenic ca, usually Squamous cell type, affecting left lung apex,
      2. eroding ribs (1st and 2nd)
      3. Involving brachial plexus and sympathetic chain (Horner’s syndrome.)
      4. Pancoast Tumour:


MRI is optimal modality to demonstrate the extent of superior sulcus tumor.Q

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