Alveolar microlithiasis

small, calcific density nodules spread throughout both lungs, more so in the lower zones

Pulmonary AVM

Descending thoracic aortic aneurysm

Allergic Broncho Pulmonary Aspergillosis

FINGER IN GLOVE

On ct-appear as band like abnormalities in expected position of bronchi

Bronchiectasis-proximal bronchiectasis (characterstic finding and highly specific for ABPA)
  Distal airways remain normal and patent

Silicosis

CXR-

1) 1-3 mm round well-defined nodules in the posterior portion of upper 2/3 rd of lungs , symmetric

  -Sometimes calcified

  -With time the nodules increase in size and number and may involve all zones

2) Reticular pattern may also be noted

CT-

1) Centrilobular micronodules

   -Upper zone preponderance (spreads anteriorly and inferiorly as the disease progresses

   -Subpleurally  the nodules may cluster to form “pseudoplaques”

   -Larger nodules may calcify

Malignant mesothelioma

1) Extensive nodular or lobular thickening of the pleura which may conglomerate to form a circumferential lobular sheet of  soft tissue density encasing the lung
  - Often runs into fissures accompanied with varying amounts of pleural fluid
   * neoplastic encasement of lung fixes the mediastinum ,so  mediastinal shift away from the site of effusion is not seen in MM
 2) Ipsilateral volume loss
 3) On CT- soft tissue density of tumor tissue is easily distinguished from adjacent pleural effusion ; but when nodules are tiny the only CT feature may be pleural effusion
 4) Calcification -rare

Septic emboli

*diagnosis may be first suggested at chest CT as abnormalities may be seen on CT even before blood cultures become positive

     CXR and CT appearance-
1) Multiple pulmonary opacities - may occur in any portion of lung (but usually maximal in lower zones)
-Either round (nodular) in shape or wedge shaped densities based on pleura and pointing towards hilum (like an infarct)
-Frequently cavitate
Air bronchograms frequently seen in all types of opacity including nodular lesions on CT

2) feeding vessel sign-
  Common CT finding of both sterile and infected infarcts
  It is a distinct vessel leading to apex of  a peripheral area of consolidation
  Not specific for embolic sequelae  but seen more frequently with septic emboli and sterile thrombo-embolic infarctions than in other conditions

3) Pleural effusion and empyema - common features

Hypersensitivity pneumonitis

  CXR-

1) Ground glass opacification

2) Fine nodular or reticulonodular pattern (more prominent in sub acute phase)

   [ Lower lung predominance ]

3) Chronic cases - fibrosis with upper lobe retraction, reticular opacity, volume loss and honeycombing may be seen

HRCT-
1) Poorly defined centrilobular nodules - < 5 mm in diameter , profuse throughout the lung ,but a mid to lower lung zone predominance noted (*ground glass attenuation)
   - Usually regress with removal of exposure
2) Ground glass attenuation - most common in AHP
    - may be patchy or diffuse
    - middle lung zone predominance
    - may resolve with removal of exposure

Miliary TB

   Widespread fine nodules , unifomly distributed and equal in size

   As there is a threshold below which nodules are invisible , miliary TB can be present in patients with normal chest radiograph

   More  readily detected with HRCT and have a random distribution in relation to secondary pulmonary lobule

   Miliary TB does not leave residual calcification

Extramedullary hematopoesis

• usually consist of paravertebral soft tissue masses(caused by extrusion of marrow through the thinned cortex of the posterior ribs)

Pt. may be asymptomatic or paraplegia from cord compression

Common anemias resulting in EMH –

   congenital hemolytic anemias-thalassemia,hereditary spherocytosis,sickle cell disease

Swyer James

CXR-

1) Unilateral transradiancy (due to reduced lung perfusion)

Size and no. of mid lung and peripheral vessels are reduced on affected side

2) Contralateral plethoric lung (due to increased blood flow)

3) Small hilum on involved side (but lung volume is normal or only slightly decreased)

4) mediastinum- may show some shift to affected side

5) Ipsilateral air trapping- key finding

Pan acinar emphysema

• Uniform non selective destruction of the entire acinus
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• Often associated with alpha-1-antitrypsin deficiency
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• Hyperinflated lung fields
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• Diffuse simplification of lung architecture with septal and vascular distortion with pruning
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• Paucity of vessels, bullae

Bronchocoele

• Dilated mucus filled bronchi
• Seen distal to a carcinoma obstructing segmental / sub-segmental bronchus 
• Seen as peripheral tubular density, may branches.
• Causes – bronchial carcinoid, endobronchial mets, cong.bronchial atresia and ABPA.

Pulmonary hamartoma

• 90% peripheral & present as solitary nodule
• Well-defined nodule with normal surrounding lung
• Popcorn calcification –diagnostic
• Central fat density – diagnostic
• DD-chondrosarcoma
• Carney’s triad – pulmonary chondroma, gastric leiomyosarcoma and functioning non-adrenal paraganglioma

Pulmonary avm

Plain film- racemose opacity with draining and feeding vessels.

CT- homogenous serpentine opacity in a bronchopulmonary segment with calcification

Bronchial carcinoid

• polypoid tumour
• collar button lesion-involves the parenchyma and bronchi
• supplied by bronchial circulation
• causes atelectasis or bronchiectasis 

Bronchopleural fistula

• return of mediastnum to midline, presence of increasig air and decreasing fluid in pneumonectomy space, contralateral aspiration pneumonitis

• “Split pleura” sign on CT

• Delayed onset(>6 months later) indicates tumor recurrence

Histoplasmosis

1.Transient bilateral non segmental bronchopneumonic pattern

2.Nodules,punctate calcification

3.central calcification-target lesion

Hydatid cyst lung

water lily sign or sign of Camalote, 
floating membranes
communication with bronchial tree-meniscus sign, double arch sign,crescent sign

Anterior mediastinal mass - Thymic cyst