Chest x-rays and HRCT interpretation Flashcards
What is the hallmark finding on CTPA that indicates an acute pulmonary embolism?
Polo mint sign
Fresh thrombus (grey) located in centre of lumen (thin rim of white contrast)
What are the 4 hallmark findings on HRCT that can indicate bronchiectasis?
Signet ring sign
Tram tack sign
String of pearls sign
Bunch of grapes sign
What is the signet ring sign on HRCT, and what condition does it indicate?
Bronchus is markedly dilated (ring) compared to accompanying pulmonary artery (signet): Suggests bronchial dilation
Bronchiectasis
What is the tram-tack sign on HRCT, and what condition does it indicate?
Parallel linear opacities along the length of the bronchi show thickening
Cylindrical bronchiectasis
What is the string of pearls sign on HRCT, and what condition does it indicate?
Uneven constriction and dilation of the bronchi
Varicose bronchiectasis
What is the bunch of grapes sign on HRCT, and what condition does it indicate?
Dilation of the bronchi forms intermittent pouches
Cystic bronchiectasis
What are the 3 hallmark findings on HRCT that indicate early pulmonary fibrosis?
Interlobar septal thickening
Irregular pleural thickening
Reticular (net-like) opacities in the lobes (bilateral)
What are the 2 hallmark findings on HRCT that indicate advanced pulmonary fibrosis?
Interlobar septal thickening
Honeycombing in subpleural areas
What is the hallmark finding on HRCT that indicates pneumothorax?
Thin, sharply-defined opacity that is the visceral pleura
Grey area is compressed lung
Black area that contains no lung markings is peripheral to visceral pleura line, indicates air
What is the hallmark finding on HRCT that indicates pleural effusion?
Grey area peripheral to visceral pleura line (thin, sharply-defined opacity)
What is a CTPA?
CT pulmonary angiogram
Scan of the pulmonary arteries
What is a HRCT?
High resolution CT
Scans chest in 1mm slices (16 total) to provide detailed imaging of lung tissues
When is CTPA indicated?
Pulmonary embolism
When is HRCT indicated?
Bronchiectasis
ILD
CTD-ILDs
Before interpreting a scan, which patient details should you confirm?
Patient name
DOB
Hospital number
Date and time of scan
In CXR interpretation, how do you comment on the adequacy of the scan?
P: Projection: Is the scan PA or AP, if it doesn’t say assume PA
R: Rotation: Are the medial aspects of clavicles both equal distance from the spinous processes
I: Inspiration: Can you see 8/9 posterior ribs
M:
P: Penetration: Are the vertebrae visible behind heart
In CXR interpretation, what order do you use to comment on the scan?
ABCDE
In CXR interpretation, what does A stand for?
A: Airway
- Trachea: Should be central or slightly to right of aortic notch
- Carina and bronchi: Should be clear
- Hilar lymph nodes: Left and right should be similar size
In CXR interpretation, what does B stand for?
Breathing
- Lung fields: Compare upper, middle, lower zones of both lungs and see if they are similar, are there any decreased/increased densities
- Pleura: Do lung markings extend all the way to chest wall, do pleura look thickened
In CXR interpretation, what does C stand for?
Cardiac
- Are the heart borders clear or shaggy
- Is the cardiac width less than half of the thoracic width
- Is there heart or mediastinal shift
In a CXR interpretation, what does D stand for?
Diaphragm
- Is the right hemidiaphragm higher than the left diaphragm
- Are the hemidiaphragms curved normally or abnormally flattened
- Are the costophrenic angles sharp or blunt
- Can you see the gastric bubble
In CXR interpretation, what does E stand for?
Everything else
In CXR interpretation, how can you tell where the pathology is in the lungs?
Silhouette sign: Normal adjacent anatomical structures of differing densities form a crisp contour or ‘silhouette’, when this is lost you can tell which lobe is affected
In CXR interpretation, how should you point out abnormalities within the struture?
PRIMP
Comment on any obvious abnormalities and what pathology it could be
Go through ABCDE
Summarise findings again
In CXR interpretation, what does silhouette sign of the left heart border suggest?
Pathology is in the lingula of the left upper lobe
In CXR interpretation, what does silhouette sign of the right heart border suggest?
Pathology is in the right middle lobe
In CXR interpretation, what does silhouette sign of the left hemidiaphragm suggest?
Pathology is in the left lower lobe
In CXR interpretation, what does silhouette sign of the right hemidiaphragm suggest?
Pathology is in the right lower lobe
In CXR interpretation, what does silhouette sign of the aortic notch suggest?
Pathology is in the left upper lobe or middle mediastinum
In CXR interpretation, what does the pathology being above the right heart border suggest?
Pathology is in the right upper lobe
What are the main CXR findings of a tension pneumothorax?
- A: Tracheal deviation away from the air
- B: Loss of lung markings on affected side, can see the lung edge
- C: Mediastinal shift and heart shift
- D: Depressed diaphragm on side of air entry
- E: Could be fractures, iatrogenic trauma
What are the main CXR findings of a simple pneumothorax?
- A: Trachea is central
- B: Loss of lung markings on affected side, can see lung edge
- C: Mediastinum isn’t shifted, heart isn’t shifted
- D: Depressed diaphragm
- E: Could be fractures, iatrogenic trauma
What are the main CXR findings of COPD?
A: Trachea central
B: Lung fields symmetrical, can’t see lung edge
C: Heart and mediastinum is normal
D: Depressed diaphragms
E: Nothing else
Can count more than 8/9 posterior ribs: Hyperinflation
What are the main CXR findings of pleural effusions?
A: Trachea central or deviated away from large pleural effusions
B: Can see lung edge, loss of lung field markings, fluid ‘white-out’ appearance
C: Heart is normal size, borders can be obscured
D: Meniscus sign (costophrenic angle blunting)
E: Can be trauma to ribs, ECG leads which suggest heart failure
What are the main CXR findings of pulmonary edema?
A: Trachea central
B: Kerley B lines (horizontal lines near the pleura), batwing opacities starting from the hilum
C: Cardiomegaly
D: Costophrenic blunting
E: ECG leads, pace maker
What are the causes of solitary pulmonary nodules on CXR?
C – Cancer
A – Abscess
S – Solitary Metastasis
H – Hamartoma
P – Pseudotumor
L – Lymphoma
E – Echinococcus
A – Actinomyces
S – Sequestration
What are the causes of cavitating lung lesions on CXR?
Lung abscess
Mycobacterium tuberculosis (mostly in upper lobe)
Primary squamous cell carcinoma of lung
Lymphoma
Kaposi sarcoma
RA, granulomatous disease eg. sarcoid
Bullous emphysema
What is a pneumoperitoneum, and what are common causes?
Free air in peritoneum cavity
Intestinal perforation eg. perforated tumour, peptic ulcer, abdominal trauma
What are the causes of upper lobe pulmonary fibrosis?
S: Silicosis, sarcoidosis
C: Coal worker’s pneumoconiosis
H: Histiocytosis
A: Ankylosing spondylitis, allergic bronchopulmonary aspergillosis
R: Radiation
T: Tuberculosis
What are the causes of lower lobe pulmonary fibrosis? RASCO
R: Rheumatoid arthritis
A: Asbestosis
S: Scleroderma
C: Cryptogenic fibrosing alveolitis
O: Other eg. bleomycin, methotrexate, amiodarone, nitrofurantoin
Where on a CT scan is the right subclavian artery?
1
Where on a CT scan is the left subclavian artery?
4
Where on a CT scan is the right common carotid artery?
2
Where on a CT scan is the left common carotid artery?
3
Where on a CT scan is the right lung?
5
Where on a CT scan is the left lung?
6
Where on a CT scan is the trachea?
8
Where on a CT scan is the oesophageus?
7
