13. Imaging techniques in pulmonology

What is a chest x ray + fluoroscopy used for

• create 2D image

• fluoro- functional information about lung function

What are the standard projections of a CXR

• PA

• AP

• Lateral

What are the indications of imaging

• asymptomatic → low dose CT screening, staging

• symtpomatic- suspicion of lung disease, cancer, chest trauma, PTX, HF

• unconscious, polytrauma

• follow up

• intervention techniques

What are the contraindications of imaging

• pregnancy

• extreme obesity

What are the shadows seen on a CXR

• Intrapulmonary

  • alveolar, interstitial, blood vessels shade, bronchial shadow

• Extrapulmonary

  • pleural, extrathoracic

• Findings

  • nodules, pulmnoary infiltrates, line/ linear shadows, coverage

What are the different nodules seen on a CXR

• solitary

• multiplex

describe the appearance of bengin nodules on a CXR

• round

• segmented

• sharrp edges

• central calcification- popcorn

• well defined boundary

Describe the appearance of malignant nodules on a CXR

• irregular

• spiculated

• blurred contour

• eccentric calcification

What are the causes of calcerous deviations 

• hamarthoma

• TB

• malignancy

What are the regular settlings seen on a CXR

• TB- apical location due to increased ventilation

• Metastasis- base due to increased perfusion

What are the pulmonary infiltrates seen on a CXR

• Bronchopneumonia

  • spotted structure- patchy, inhomogenous

  • multifocal

• Lobar pneumonia

  • respects borders of lobes

  • airbronchogram

What are the causes of atelectasis shadow

• lung cc

• compression of LN

• mucous plugs

• foreign body

• pleural effusion

• abdominal diseases

What are the causes of infiltrate shadow

• pneumonia

• lung cc

• TB

• pulmonary infarction

What are the causes of scattering shadow

spread/ dissemination

• coniosis

• granulomatous disease

• TB

• metastasis

• sarcoidosis

What are the causes of linear shadow

• pulmonary embolism

• lymphangiosis carcinomatosa

What are the causes of nodular shadow

• primary lung cancer

• metastasis

• tuberculoma

• benignoma

• arteriovenous malformations

• echinococcus

What are the causes of hilar expansion shadow

• central lung cc

• mediastinal tumours

• sarcoidosis

• lymphomas

• oesophagus dilation

• pulmonary circulation’s stagnation

What are the causes of vessel shadow

• pulmonary hypertension

• dilation of vessels

What are the causes of pleural effusion shadow

Meniscus sign

What are the causes of Barbelll shadow

• focal TB + lymphangitis + enlarged hilar LN

What are the causes of Kerley line shadow

Pulmonary oedema

What are the causes of apical bullous emphysema shadow

Thin walled sacs

What are the causes of bronchial shadow

• thickened bronchial wall

• Tram track lines

• signet ring

• Bronchiectasis

What are the causes of calcificated residual nodules shadow

• curvilinear opacities

• extend from subpleural mass towards hilum

• distortion of vessels and bronchi that lead to an adjacent area of rounded atelectasis

• TB, asbestos, pleuritis, tumour 

What are the causes of fissures shadow

Horizontal, oblique

Intrapleural recess

• outlined if thickened

• if in pleural soace- air, effusion, other appearing

What are the causes of basket shadow

Pulmonary abscess

What are the causes of aspergilloma shadow

mycetoma, fungus ball

What are the causes of cavity shadow

TB, tumour

Calcareous tisssue- hamarthoma, tumour, tb

What are the Negative shadows on CXR

• watermark sign

• airbronchogram

What is a watermark sign on a CXR

• behind obstruction or valvular bronchoconstriction

• lung parenchyma= brighter or with increase transparency

What is an air bronchogram on CXR

• when no air in alveoli

• surrounding lungs infiltrated

• bronchial lumen outlined

What can cause volume increase on CXR

• intrapulmonary

  • inflammation, haemorrhage, pleural fluid, hematoma, pneumothorax

Needs more space than usual- size of lung is unchanged

What causes volume decrease on CXR

• Atelectasis

• Fibrosis

• pneumectomy

What are the differences in effusion and atelectasis

• Effusion

  • mediastium pushed away

  • diaphragm pushed down

• Ateletcasis

  • mediastinum pulled

  • diaphragm raise

What are the different appearances of pneumothorax

• partial- apical, basal

• cape like

• complete

• tension

• sero/ hydro PTX

• mediastinal

What is the Ellis Damoiseau line

curved upper border of a pleural effusion

• concave upward

• homogeneous opacity

What are the advantages of chest fluoroscopy

• shows movement of diaphragm

• pulsation of heart, hilus

• judgement of paradoxical movement

• Holzknecht Jacobson sign

• eliminate superposition, localisation of target lesion

What are the disadvantages of chest fluoroscopy

• higher radiation exposure

• bad resolution

• documentation is difficult

What is the Holzknecht Jacobson sign

• pendulum movement of mediastinum during inspiration and expiration

• hilus moves towards the obstructed lung during inspiration, expiration teh other direction

What can be seen on contrast enhanced fluoroscopy

• enlargement of heart

• chest tightness

• contrast media passe through

• locate/ rule out fistula- aspiration

• confirm hiatus hernia

What are the indications for a CT

• suspisious CXR, inaccurate difference

• tumour staging, RECIST

• intesrstitial lung disease

• lung transplant patients

• traumatology

• negative CXR, abnormal spirometry, chronic cough

• CT guided biopsy

What are the uses of CT angiography

• vessel representation

  • normal/ abnormal vessels

  • AVM, VCS syndrome

  • thromboembolic process

• representation of parenchymal organs

• 3D reconstruction of plane

What is a virtual bronchoscopy

used before interventio of trachea, for planning

What are the uses of HRCT

• morphology reflects morphological function

  • only in exams by inhalation and exhalation- air trap, obstruction

• ILD, bronchiectasis, COPD

• pulmonary fibrosis, CF, pneumonia, COVID

What is the indicatio of low dose CT

screening for lung cancer

What can US be used to detect

• pleural fluid

• heart + big vessel abnormalities

• close pathologies of thorax and pleura

• pneumothorax

What are the advantages of US

• non invasive, non ionising

• cheap, no prep needed

• simple, fast

What are the disadvantages of US

• air makes exam hair

• disturbing shadows can occur

• fat can cause deflection and increased attenuation

• accuracy is dependent on examiner

What are the indications for an MRI

• for chest wall + mediastinal structures

• pancoast tumour, hematoma

• DWI- pathological lymph nodes

• detection of perfusion disorders

What are the indications for PET CT

• detection of primary/ metastatic cancer

• staging of cancer

• follow up after cancer therapy

• before invasive procedures