Imaging Thorax Flashcards

1
Q

CXR interpretation order

A
  • Name, DOB, date and time film taken, any previous imaging, type of imaging (plain film, CT)
  • Image quality: RIPE
  • RIPE –> Rotation(medial aspect of each clavicle equidistant from spinous processes, spinous processes vertically orientate against vertebral bodies),Inspiration(adequately inspirated (5-7 ribs), adequate penetration,Projection(AP vs PA), Exposure (left hemidiaphragm visible to the spine and vertebrae visible behind the heart)
  • Systems/ structures –> ABCDEFGHI
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2
Q

ABCDEFGHI acronym for CXR?

A

Airway

Bones and tissues

Cardia

Diaphragm

Edges of pleura

Fields of lungs

Gastric bubble

Hila

Instruments and wires

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3
Q

How would you present a CXR using a structured approach?

A
  1. State type of image, notable demographics and presenting complaint if known
  2. state adequacy of film
  3. describe main abnormality –>
    • appearance; patchy, focal, well rounded…
    • Location –> split lung into “zones”- upper, mid and lower
  4. Review areas:
    • lung apices
    • the heart
    • the diaphragm
    • the bones and soft tissues
    • any lines/ wires?
  5. State differential diagnoses based on your findings
  6. Say what you would like to do next
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4
Q

Name the main visible structures you may see on an Xray

A

Visible structures:

  • Trachea
  • Hila
  • Lungs
  • Diaphragm
  • Heart
  • Aortic knuckle
  • Ribs
  • Scapulae
  • Breasts
  • Bowel gas
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5
Q

Name some important obscured structures you may see on xray?

A

Sternum

Oesophagus

Spine

Pleura

Fissures

Aorta

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6
Q

Label the structures

A
  1. 1st rib –> remeber tends to wrap around
  2. Aortic knuckle
  3. Left upper lobe
  4. Aortopulmonary window
  5. Left heart border –> represents left ventricle
  6. left oblique fissure
  7. gastric bubble under diaphragm
  8. left lower lobe
  9. costophrenic angle
  10. right lower lobe
  11. right oblique fissure
  12. right middle lobe
  13. right heart border
  14. horizontal fissure
  15. right hilum
  16. right upper lobe
  17. right paratracheal stripe –> can be seen on most CXR, should not be wider than 4mm thickness, made from right wall of trachea, adjacent pleura of R lung and fat. If widened can be a sign of thyroid and parathyroid cancer and lymph node enlargement
  18. trachea
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7
Q

Surface anatomy:

Where can you find the left oblique fissure?

Where can you find the right oblique fissure?

Where can you find the horizontal fissure?

A
  • Left oblique fissure –> Arises between spinous processes T3-T4, follows the 5th intercostal space laterally, follows the contour of the 6th rib anteriorly
  • Right oblique fissure –> begins at T4 spinous process, 5th intercostal space laterally and follows the contour of the 6th rib anteriorly
  • Horizontal fissure –> Arises from right oblique fissure –> follows the 4th intercostal space from the sternum and meets the oblique fissure as it crosses the 5th rib
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8
Q

What shape is the AP (aortopulmonary) window normally?

What traverse the AP window?

Why is this important?

A

AP (aortopulmonary window) is normally concave. It is the concave space inferior to the arch of the aorta and superior to the pulmonary trunk.

The most common reason for a straightened or convex lateral border is mediastinal lymphadenopathy.

Traversing the AP window:

  • Left phrenic nerve
  • Left recurrent laryngeal nerve
  • Left vagus nerve
  • Left bronchial arteries
  • Ligamentum ateriosum (remnant of ductus arteriosus)
  • Fat
  • Lymph nodes
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9
Q

What is consolidation?

how does it appear on CXR?

A

Consolidation - any pathologic process that fills the alveoli with fluid, pus, blood, cells (including tumor cells) or other substances resulting in lobar, diffuse or multifocal ill-defined opacities.

.

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10
Q

What is lung/ lobar collapse?

A

Lobar collapse = signs of volume loss and absence of air bronchograms

Air bronchogram = air filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/ white). Almost always caused by pathologic airspace/alveolar process, in which something other than air fills the alveoli.

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11
Q

What is atelectasis?

A

atelectasis is used generally for partial collapse, often unilateral affecting part or all of one lung.

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12
Q

What is the silhouette sign?

Why is it useful for indicating the site of pathology?

A

Usually different densities of adjacent structures causes a silhouette

Pathological loss of differentiation between two adjacent structures.

Used to localise areas of opacities, atelectasis or mass within the lung.

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13
Q

What is a useful way of remembering the imaging features of consolidation?

A

A2BC3

  • A- Acinar rosettes“fluffy” appearance of the parenchyma distal to the terminal bronchiole (acini at the end of the terminal bronchiole filled with tissue/ fluid)
  • A- Air bronchograms
  • B - bat wing distribution
  • C - confluent ill defined appearance
  • C - consolidation - diffuse/ perihilar/ bibasal, lobar/ segmental, locular/multifocal
  • C- changes occur rapidly
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14
Q

Is the image on the L collapse or consolidation?

A
  • Can see this fissures, trachea is central, hilum still visible
  • Consolidation over the R upper lobe.
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15
Q

Consolidation or collapse?

A

This is an example of L upper lobe lung collapse:

Trachea is deviated, general opacity over the left lung, loss of heart border, loss of aortic knuckle (obscured). Loss of silhouette sign, loss of contrast.

Left upper lobe collapse becomes thin sheet like appearance –> Veil sign

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16
Q
A
  • Loss of left lower heart border, hilum are at the same level indicating something is pulling down, loss of silhouette sign.
  • Know there are two lobes in the lung, left lower lobe collapse
  • Called retrocardiac “Sail sign”
17
Q
A

Diagnosis: Right middle lobe collapse this is a PA chest radiograph of a child.

Signs:

Lost the right heart border

The trachea is visible, child has inhaled a foreign body and it has caused right middle lobe collapse.

(due to angle of right bronchus foreign body has gone down R main bronchus).

Horizontal fissure lost, hilum lost.

18
Q

Collapse vs consolidation?

Loss of silhouette sign?

Which lobe is affected?

Why should you be especially aware when you see this sign on a CXR?

A

Diagnosis: R upper lobe collapse

Called the golden S sign.

When this sign is seen you should be especially suspicious of a carcinoma. The mass can block the R upper bronchus, causing R upper lobe collapse. Lobe rotates backwards, causing backwards S shape.

19
Q

What is the diagnosis in this image?

Are the hilar level?

Are the lung markings obvious?

What is the tx for this diagnosis?

A
  • Hilar look level, Left should be higher than the right
  • Lung markings generally seen well until the left upper lobe.
  • Air compressing the lung down, due to the compression the hilar are at the same level.
  • Diagnosis: Tension pneumothorax
    • If suspicious of tension pneumothorax clinically —> never wait for CXR
    • TX: 14G cannula in the 2nd intercostal space, midclavicular line.
20
Q

Is this ET tube placed correctly?

A
  • This ET has entered the R main bronchus
  • This is dangerous as will overinflate the R lung without allowing airflow to the L
21
Q

Is this ET tube placed correctly?

A
  • This ET tube is placed correctly, can see it following the trachea centrally up to the carina, both the R and L main bronchi are visible.
22
Q

Why are ET tubes used?

How are they shown on CXR?

What is the risk?

What are the rules for placement?

A
  • ET tubes are inserted into the trachea to allow artificial ventilation
  • Radioopaque strip so that they are visible on CXR
  • The risk = left lung collapse and hyperinflation of the R lung

Rules for placement:

  1. Ax mandible position in the CXR –> is the neck flexed, neutral (mandible over C5/C5) or extended?
  2. Desired position is 5 +/- 2cm above the carina if the neck is neutral

Flexed neck - 3cm (+/- 2cm)

Extended neck - 7cm (+/- 2cm)

23
Q

What is the tube shown on this CXR?

Is it correctly placed?

A

This is a NG tube. It is not correctly placed, but actually going down the L main bronchus.

24
Q

How can be make sure NG tube placement is safe?

A

Must request for special CXR to check the position –> must see the tip of the tube below the diaphragm.

The risk = feeding into the resp sx which can be disastrous

4 points to check:

1) Tube descends the thorax in the midline
2) Tube bisects the carina
3) Tube crossed the diaphragm in the midline
4) The tip sits below the diaphragm.

25
Q

Case 1:

25 yr old man, recently has major surgery, presents with 3 day hx of SOB, chest pain, haemoptysis

Wells score = 5 ( Wells’ Criteria risk stratifies patients for pulmonary embolism (PE) )

What would 1st line imaging be? why?

What are the differentials?

What if the pt was a pregnant female? what would your first line imaging be? If she has signs and sx of DVT? If she doesnt have signs or sx of DVT?

A
  • Most likely diagnosis = PE, potentially infection, potentially tumour
  • 1st line –> CXR (for lowest dose of XRAY), CT scan next if sure of PE diagnosis
  • Gold standard imaging test for PE = CT pulmonary angiogram (using contrast).
  • Do not perform D-dimer test in pregnancy (always comes back as a false positive). (D dimer test = fragment of cross linked fibrin, can detect if abnormally raised, negative predictor value, if not present highly unlikely individual has DVT/PE. However no positive predictor value, can be raised by many conditions).
  • In pregnancy first line investigations = ECG and CXR (ECG can sometimes have slight characteristics of PE, plus CXR to rule out any other diagnosis).
  • If woman has signs and sx of DVT –> compression duplex ultrasound is enough if positive
  • If woman is w/out signs and sx of DVT can do ventilation/ perfusion scan (V/Q lung scan) or CTPA (CT pulmonary angiography) scan.
  • If CXR is abnormal (but not diagnostic) plus clinical suspicion of PE, CTPA should be done in preference to V/Q scan.
  • V/Q scan might carry increased risk of childhood cancer compared to CTPA, but associated with lower risk of maternal breast cancer. Risk of both is small.
26
Q

CTPA - normal or abnormal?

A

Abnormal, two clots shown in both branches of the pulmonary artery.

27
Q

What is used during a V/Q scan?

A
  • Radioisotope scan uses:
    • radioisotope labelled technecium- 99m through aerosol (ventilation) and IV (perfusion) to assess for PE.
    • By seeing radionucleid emitted when it decays you can see the concentration of radionuclide being delivered either ventilatory or circulatory
    • If reduced during IV –> evidence due to PE.
28
Q

75 yr old smoker presents w 1 yr history of gradually worsening dysponea on exertion and dry cough

Examination shows he is cachectic, has finger clubbing and fine end-inspiratory crackles on ausculation of the lungs.

Pulmonary lung function tests show the FEV1: FVC ratio as normal

What initial imaging investigations will you do? Why?

What is the gold standard imaging investigation?

A
  • CXR initial imaging –> differentials thinking lung carcinoma, chronic lung conditions, HF
  • Reticulonodular shadowing shown on pts CXR –> reticular and linear opacification is caused by a decrease in the ratio of gas to soft tissue, due to a pathological process centred in or around the pulmonary intersitium.
  • Gold standard imaging = High resolution CT (HRCT)
  • Latice/ honey comb pattern of pulmonary fibrosis, plus bullae formation –> diagnostic of COPD.
29
Q

Case 3: 60 yr old female 4 week hx reduced exercise tolerance and breathlessness

Sharp pain on left with inspiration

Differentials?

First line imaging?

A

Differentials –> pneumonia, decompensating HF, pleural effusion, rib fracture

First line imaging –> erect PA CXR

CXR –> shows pleural effusion with meniscus line of fluid, 250-600 ml of fluid is required before it becomes evident on PA CXR –> common causes are CHF, infection, trauma, PE, tumor, autoimmune, renal failure

30
Q

Case 3 continued:

Unilateral pleural effusion found to be secondary to pleural metastases, she requires symptomatic drainage of the effusion.

What imaging will you use to help for the drainage and why would you choose this?

A

Therapeutic aspiration –> Thoracocentesis

Ultrasound allows detection of small amounts of fluid (as small as 3-5ml)

Ultrasound guided aspiration is reliable and fast

Enables loculated effusions to be drained. (Fibrotic scar tissue may form in the pleural cavity (called loculation), preventing effective drainage of the fluid.)