Diseases characterised by Parenchymal opacification Shivaprakash B Hiremath DNB Resident
Oct 26, 2014
Diseases characterised by Parenchymal opacification
Shivaprakash B HiremathDNB Resident
Normal lung density
•Slightly higher than air
Air in airspaces and small airways
Interstitial lung tissues
Wall of the alveoli
Small airways
Capillaries, blood in these
Vs
Increased lung opacity< in the amount of air
> size / volume of soft tissues
• Reduction in the volume (expansion) of the airspaces
• Partial or total replacement of the air in the airspaces by fluid or cells
• Increase in blood flow and blood volume in vessels
• Thickening of the interstitial tissues and of the alveolar wall
Degree of Opacification
•“Ground-glass opacity” - hazy increase in lung opacity that does not obscure the underlying vessels and bronchi
•“Lung consolidation” or “consolidation” - vessels and bronchial walls are obscured
•“Increased lung attenuation that have a density that is greater than soft tissue density”▫Development of calcifications within
existing lesions ▫Deposition of calcium within the lung
parenchyma ▫Diffuse or multifocal pulmonary ossification
Ground Glass Opacity
• Patchy distribution of ground-glass opacity Pneumocystis jiroveci pneumonia
Focal Vs Diffuse
Focal Vs Diffuse
Ground Glass Opacity
Diffuse ground-glass opacity Hypersensitivitypneumonitis
• Pulmonary haemorrhage in the right middle lobe
• Ill-defined GGO
• Sharply defined area of GGO in RUL• Pulmonary haemorrhage
GGO located near centre of the secondary pulmonarylobules and then look like ill-defined nodules
Reduction of Air in the Airspaces
•Volume Loss of the Alveoli▫Physiological phenomenon – development
of ground-glass opacity▫Increase in density in dependent lung
regions Lower lung > Middle and upper zones
Greater diaphragmatic movement Gravitational effectProne scans
Dependent density is no longer visible against the posterior chest wall and may appear against the anterior chest wall
•Volume Loss of the Alveoli▫Pathological changes in the lung and pleura
Fibrotic scarring in the lung Pleural thickening
Restrict lung expansion Ground-glass opacity
Decreased expansion right lung due to Right-sided malignant mesothelioma
•Replacement of Alveolar Air▫Partial filling of the alveolar spaces by fluid or
cells Alveolar proteinosis Respiratory bronchiolitis, bronchiolitis Interstitial lung disease Alveolar haemorrhage Bronchioloalveolar cell carcinoma
•Partial filling of the alveolar spaces + Thickening of the interstitium, alveolar walls = Crazy paving
Alveolar proteinosis• Areas of ground-glass opacity with intralobular reticular
pattern superimposed creating the crazy-paving pattern
• Increase in Parenchymal Perfusion▫> in capillary blood volume = > in lung
density▫Mosaic perfusion = Areas with >
attenuation (GGO) + < attenuation
Mosaic perfusionDecreased attenuation Increased lung attenuation
• Narrowing or obstruction of the blood vessels
• Small airways narrowing▫ Reflex vasoconstriction
• Redistribution of blood flow
GGO Vs Mosaic perfusionCalibre of the blood vesselsDelineation of the ground-glass opacityDensity changes after deep expiration
• Mosaic perfusion secondary to recurrent pulmonary embolism
Thickening of Parenchymal Interstitium / Alveolar Wall
•Minimal thickening of the alveolar wall, parenchymal interstitium = groundglass opacity
•Inflammation or infiltration•Intraalveolar cellular infiltrate, filling the
airspaces•Acute inflammation i.e indicating active
disease or reactivation of disease
•GGO ▫Fibrosis and result from fibrotic thickening
of the alveolar wall and interstitium•Be careful to diagnose GGO as an active
process▫Traction bronchiectasis or honeycombing
• Usual interstitial pneumonia in Systemic sclerosis• GGO in the dorsal and basal subpleural region of both
lungs, i.e active lung disease
•When a lung biopsy is performed, areas of ground-glass opacity are the best locations to be targeted, especially when no signs of fibrosis are present
• Diffuse ground-glass opacity in chronic hypersensitivity pneumonitis
• Bronchial deformation indicates pulmonary fibrosis
Acute Versus Subacute or Chronic Disease
Crazy-Paving Pattern
•Superposition of a linear pattern on ground-glass opacity = Crazy paving
•Pulmonary alveolar proteinosis
• Acute radiation pneumonitis in a patient treated for left-sided breast cancer
• Ground-glass opacity and consolidation
• Faint intralobular reticular pattern
• Crazy-paving pattern
Lung Consolidation
•Increase in lung density with obscuration of the underlying vessels & bronchial walls
•Bronchi can be recognised as an air bronchogram, i.e. low-density branching tubular structures
•Lung consolidation are similar to the lung changes that are responsible for ground-glass opacity
•Most frequent cause is a decrease in the amount of air in the airspaces
•Replacement of this air by fluid, cells, tissue or other substances
•Interstitial pneumonia (UIP)•Sarcoidosis
• Subpleural areas of lung consolidation• Eosinophilic pneumonia
Consolidation margins
•Consolidation has one or more sharply defined borders because the pathology reaches an anatomic structure such as a fissure
•Borders of consolidation that are not adjacent to the fissure may be,▫Sharply defined ▫Irregular and blurred▫Possibly surrounded with ground-glass
opacity
Sharp delineation by major fissure
• Lung consolidation and ground-glass opacity in a patient with overwhelming pneumonia
• Pulmonary infection with lung consolidation and GGO
•Airspace filling is the most frequent cause of consolidation, this pattern is often associated with,▫presence of centrilobular airspace nodules -
early airspace filling, ▫i.e bronchial distribution
Diseases producing ID-GGO:
•Diffuse pneumonias•Primarily opportunistic infections•Chronic interstitial diseases•Acute alveolar diseases•Unusual miscellaneous disorders
Increased Lung Attenuation more than Soft Tissue Density•Multifocal lung calcification•Granulomatous diseases
▫Tuberculosis▫Silicosis Associated with lung
nodules▫Sarcoidosis▫Amyloidosis
Metastatic calcification
•Deposition of calcium typically within the parenchymal, peribronchovascular interstitium▫Hypercalcaemia – abnormal calcium and
phosphate metabolism▫Chronic renal failure▫Secondary hyperparathyroidism
•Areas of GGO with calcification that may be inconspicuous or very dense or present as patchy areas of consolidation
•Consolidated lung parenchyma appears abnormally dense
• Metastatic calcification• Dense centrilobular ground-glass
opacities
• Metastatic calcification in consolidated lung in chronic renal failure and secondary hyperparathyroidism
Disseminated pulmonary ossification
•Small deposits of mature bone form within the lung parenchyma▫Chronic heart disease (mitral stenosis)▫Idiopathic pulmonary fibrosis (IPF)▫Asbestosis
Amiodarone lung toxicity
•Pulmonary toxic reaction with interstitial pneumonia and fibrosis
•Consolidated lung parenchyma may appear abnormally dense
•Liver and spleen appear abnormally dense as drug accumulates in the organs