Read first the text book: Computed Tomography and Magnetic resonance of the Thorax by Nadich et all

Then go through this exercise to assess your comprehension

Fluid accumulates in pleural space. 

Irrespective of the nature of fluid, radiologically they will look similar.

Radiological criteria are:

• Upright film 
  • Density In dependent portion 
  • S ilouhette of upper limit of density
  • Upper margin high in axilla in PA view 
  • Loss of costophrenic angle in PA view
  • Note also lack of identifiable left diaphragm before and visible diaphragm after  clearance of fluid (Silouhette sign principle)
• .Lateral film
  • Anterior and posterior portions of gutter in lateral view
  • Upper margin high anteriorly and posteriorly in lateral view 
• Lateral decubitus 
  • Along sides in lateral decubitus position
•  Supine position,
  • Along posteriorly in supine position, giving diffuse haziness on the side of effusion 
• Compare the Costophrenic angle before and after clearance of effusion. 
  
  
  

Physical Findings 

• Mediastinum is in midline to start with and gradually gets shifted to opposite site as the pleural pressure becomes positive. 

• Chest Expansion decreases on the side of effusion due to decreased ventilation. 

• Resonance is dull and flat to percussion. Dullness is most in posterior base in erect position. Flatness is recognized by tapping the chest with flat of your hand. Traube's space will be obliterated on left sided effusions. 

• Breath Sounds are decreased since the ventilation to that hemithorax is decreased. Fluid is a good conductor of sound. If there is underlying consolidation a good bronchial breathing will be heard over the effusion. In massive effusions with completely atelectic lung and patent airways one can also hear bronchial breathing over the effusion. 

• Voice Transmission decreases and follows breath sound characteristics. Egophony is noted along the upper margin of the fluid. This is probably due to a thin film of fluid separating pleural space. 

• Adventitious Sounds: None 

• Hemithorax size is larger due to loss of negative pressure in pleural space. 

• Effort of Ventilation: Respiratory rate increases and use of accessory muscles can be recognized. 

Effect on Function: Can lead to central cyanosis. 



Focused Exam 

• Upper Limit of Fluid can be recognized by: 

• Percussion 

• Scratch test 

• Egophony 

• The upper limit of dullness should be horizontal across the hemithorax. 

• Shifting Dullness 

• Try to elicit shifting dullness. In prone position the previously dull pleural gutter will
  become resonant as the fluid shifts and lung floats up. Shifting dullness is demonstrable
  with ease when there is hydropneumothorax. 

• Diaphragmatic Function 
  Ipsilateral diaphragmatic function is decreased and can become paradoxical in massive
  effusions. 

• Chest Wall Edema 

• Chest wall edema is recognizable in empyemas. 

• Chest Wall Warmth 

• Chest wall increased warmth is recognizable in empyema. 

• Clubbing 

• Clubbing is associated with malignant effusions and empyemas. 

Exceptions 

• Size of hemithorax is smaller in negative pressure induced pleural effusion. 

• Mediastinal shift to the same side of effusion occurs in negative pressure induced effusion and in lung cancer with endobronchial lesion and atelectasis. Fluid accumulation in pleural space. 

Clinical Picture 

• Patients present with shortness of breath and cough. 

• Can be asymptomatic and recognized on routine CXR. 

• Dullness with decreased breath sounds and mediastinal
  shift can be seen.

Chest x-ray shows fluid in pleural space with classical meniscus. Additional findings will depend on the etiology. 

Etiology 

Multiple etiologies can give rise to pleural effusion. Following are the common. 

• Congestive heart failure 

• Malignancy 

• Parapneumonic 

• Tuberculosis 

• Rheumatoid arthritis 

Pathophysiology 

Mechanisms leading to accumulation of fluid in pleural spaces vary. Following are some. 

• Increased hydrostatic pressure eg CHF. 

• Increased capillary permeability eg malignancy 

• Direct extravasation eg Chylothorax 

Negative pressure induced eg trapped lung 

Diagnosis 

• Pleural effusions are categorized as exudates and transudates. 

• Thoracentesis is essential to obtain fluid for appropriate studies based on the clinical setting. 

• Malignancy is the most common cause of exudative effusions and should be ruled out with cytological exam.

•  In undiagnosed effusions one have to consider pleural biopsy either by blind method or by thoracoscopy.

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•  

Treatment 

• Appropriate specific therapy based on the etiology. 

• Therapeutic thoracentesis may be required to relieve shortness of breath. 

• Pleural sclerosis will be a consideration in malignant effusions to prevent recurrence. 
  
  
  

Q1: What are the characteristics of Fissural pseudo-tumors

Answer

Q1: What are the characteristics of Fissural pseudo-tumors

• Common in CHF

• Loculation of fluid within fissure

• previous inflammatory disease with adherence of pleura

• lies in expected region of fissure

• margins hazy or poorly defined

• with free communication between lateral portion of oblique fissure and pleural space fluid extends into fissure and has a triangular appearance with apex pointing towards hilum

Q2: What are the major interpretive issues with Para pneumonic effusion

Answer

Q2: What are the major interpretive issues with Para pneumonic effusion

• Differentiation from pleural and parenchymatous disease (often difficult, may exist together)

• Characterization of underlying lung disease

• free or loculated

  • Loculated effusions are most often empyema

• appearance of pleural membrane with contrast

• guidance of therapy

Q3 : How do you distinguish Empyema from Lung abscess?

Answer

Q3 : How do you distinguish Empyema from Lung abscess?

• Lung abscess

  • Spherical

  • irregularly thick wall

  • little compression of adjacent lung

• Empyema

  • lenticular in shape

  • smooth wall

  • compression of lung

Q4 : How do you distinguish Lung abscess from Necrotizing pneumonia

Answer

Q4 : How do you distinguish Lung abscess from Necrotizing pneumonia

• lung abscess

  • homogenous area of low density

  • Thick irregular wall

  • hyper vascular wall (bronchial arteries)

• Necrotizing pneumonitis

  • multiple poorly defined foci of low density

  • unassociated with enhancing margins

• Gangrene lung

Q5 : What are the appearance of pleural membrane with contrast

Answer

Q5 : What are the appearance of pleural membrane with contrast

• contrast enhancement of parietal pleura

• thickening of parietal pleura

• thickening of extra pleural sub costal tissue

• attenuation of extra-pleural fat

• pleural thickening can resolve with therapy

Q6 :  How is CT useful in guidance of therapy

Answer

Q6 :  How is CT useful in guidance of therapy

• appropriate placement when loculated

• inadvertent placement in fissure or lung

Q7: List  benign Asbestos related pleural disease

Answer

Q7: List  benign Asbestos related pleural disease

• Pleural plaques

• Exudative effusion

• Diffuse pleural fibrosis

• Round atelectasis

Q8: What are the characteristics of Pleural plaques

Answer

Mesothelial plaques: these are fibrous plaques and nodules on
pleura associated with asbestos exposure. Their presence, by
itself, does not predispose to malignant mesothelioma or
asbestos-related lung disease 

Q8: What are the characteristics of Pleural plaques

• latency period of 20-30 years

• asymptomatic

• discrete elevated sharply defined and may measure upto 1 cm in thickness

• characteristically bilateral

• follow the rib contours

• morphologically ivory white in color

• Calcification in 10%

• Calcified plaques vary from small leniar or circular shadows usually situated over the diaphragmatic domes

• acellular bundle of collagen

• due to irritation of asbestos fibers protruding through visceral pleura

• Markers of asbestos exposure

Q9: What are the characteristics of  exudative effusion

Answer

Q9: What are the characteristics of  exudative effusion

• earlier than plaques 10-20 years

• unilateral or bilateral

• recurrent

• eosinophilic

• not a risk factor for Mesothelioma

Q10: What are the characteristics of round atelectasis

Answer

Q10: What are the characteristics of round atelectasis

• folded lung

• Incidental finding

• male predominance

• sharply defined pleural-based mass

• acute angle with the adjacent pleura

• usually located posteriorly in lower lobes adjacent to pleural thickening

• air bronchogram may be present

• vessels and bronchi have curvilinear appearance "comet tail" sign

• focal volume loss

• uniform enhancement with contrast

Q11: What are the clinical characteristics of Malignant mesothelioma

Answer

Q11: What are the clinical characteristics of Malignant mesothelioma

• association with asbestos exposure

• not dose related

• crocodolite poses a greater risk

• latency period of 20-30 years

• 80% pleural 20% peritoneal

• diagnosis usually requires open biopsy

• require  EM and immunohistochemistry

• epithelial, mixed and sarcomatous

• Cough, chest pain, sob and weight loss

• clubbing of fingers

• median survival 6-12 months

• thick gray-white mass encasing the lung and exitrinsically compressing the bronchi

• grows by contiguous spread including chest wall and diaphragm

• seldom metastizes to distant sites

• extra pleural pneumonectomy vs. pleurectomy followed by radiation

Q12: What are the radiological characteristics of Malignant mesothelioma

Answer

Q12: What are the radiological characteristics of Malignant mesothelioma

• pleura markedly thickened and irregular and nodular

• often encircles lung

• mass spreading into fissures

• effusions in 80% of cases

• trapped lung

• frequently not accompanied by mediastinal shift

• spread to mediastinal nodes and contra lateral lung

Q13: List common primaries that Metastatises to pleura

Answer

Localized pleural mesothelioma

Solitary, fibrous tumor: previously known as localized pleural mesothelioma, solitary fibrous tumor of the pleura is a sessile or pedunculated mass, ranging in size from 1-36 cm. Microscopically, these are composed of bundles of bland spindle cells with elongated nuclei. The histogenesis of SFTs is controversial. Immunocytochemical and ultrastructural studies favour fibroblastic differentiation. Approximately 30% of SFTs are malignant with local invasion, recurrence and distant metastases 

Malignant mesothelioma: almost all cases are related to asbestos exposure. There are three major histologic patterns which may blend into one another 

Epithelioid mesotheliomas (60-65%): there are epithelial cells arranged in cords, nests, acini, cell balls and papillary formations. Individual malignant cells are mostly polygonal with abundant eosinophilic cytoplasma and bland nuclei 

Sarcomatoid mesotheliomas (10-15%): they have a fibrosarcoma like appearance and are composed of cells with elongated cytoplasm, arranged in parallel bundles. There is greater pleomorphism, more mitoses and worse prognosis than epithelioid mesothelioma 

Biphasic mesotheliomas (25-30%): 

Their prognosis is the same as sarcomatoid mesothelioma i.e., worse than the epithelioid type. They are composed of various mixtures of
epithelioid and sarcomatoid cells 

Immunohistochemistry (Keratin, vimentin and epithelial membrane antigen are positive) and electron microscopy (numerous long microvilli and no secretory granules) are very helpful in diagnosis 

Chest wall swelling 
Pleural biopsy 
Pleural biopsy Thoracotomy 
Encasing lung 
Low power pleura 
Alcian blue+ve 
Alcian blue(-ve) after hyaluronidase 
EM 

Q13: List common primaries that Metastatises to pleura

• Lung

• Breast

• GI tract

• Kidney

• Ovaries

• unknown primary

Q14: What are the radiological characteristics of pleural metastasis

Answer

Q14: What are the radiological characteristics of pleural metastasis

• Marked thickening

• nodularity

• pleural effusion

Q15: What are the clinical characteristics of Pleural lymphoma

Answer

Q15: What are the clinical characteristics of Pleural lymphoma

• 10% of malignant pleural effusions are due to lymphoma

• more often with non-hodgkin's lymphoma

• more often with extensive disease

Q16: What are the possible mechanisms for accumulation of pleural fluid in Lymphoma?

Answer

Q16: What are the possible mechanisms for accumulation of pleural fluid in Lymphoma?

• impaired lymphatic drainage

• obstruction of thoracic duct

• direct pleural infiltration

Q17: What are the characteristics of Post -pneumonectomy space

Answer

Q17: What are the characteristics of Post - pneumonectomy space

• rotation and ipsilateral displacement of mediastinum

• hyper aeration of the contra lateral lung

• residual fluid

• obliteration of space

Q18:  What do you have to watch for in post-pneumonectomy space?

Answer

Q18:  What do you have to watch for in post-pneumonectomy space?

• Tumor recurrence

• emphysema

• right pneumonectomy syndrome

  • dyspnea

  • recurrent pneumonia

  • shift of mediastinum causing compression of left main

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