Radiology Flashcards
Which 4 densities can be detected in x-ray?
• Air (black) • Fat • Soft Tissue • Bone (white)
Label the following:
1) Aorta
2) Pulmonary artery
3) Left auricle
4) Left ventricle
5) Right atrium
6) Trachea
7) Hemidiaphragm
8) Stomach
9) Horizontal fissure
Silhouette sign
Loss of a silhouette when you have 2 tissues of the same density are together
Middle lobe collapse
RUL Pneumonia
Consolidation
If the alveoli and small airways fill with dense material, you cant see the vessels through the lung as they are all the same density the lung
Cystic fibrosis with bronchiectasis
What defines lung tumours as peripheral tumours?
Tumours arising beyond the hilum
What defines lung tumours as central tumours?
Tumours arising at or close to the hilum
What are the cardinal signs for central tumours on CXR?
Cardinal signs:
Hilar enlargement
Distal Collapse/consolidation
Which view is used most regularly, PA or AP?
PA (minimises cardiac shadow as it is anterior so imaged last)
In terms of breathing, when should a CXR be taken?
At full inspiration
When are AP CXRs used?
Used in patients who are immobile
What are the steps to carry out before interpreting a CXR?
- Check the patient’s name and CHI
- Is there a side marker on the CXR -are you looking at the CXR the correct way round ?
- Is it technically adequate? Consider the ‘ations’: Inspiration, Rotation and Penetration (is there enough radiation?)
- Check can see normal structures: Heart/great vessel, Trachea, Pulmonary hilia, Clavicle/scapula/ribs/vertebrae
Which lies most superior, the left or right hilum?
Left
Which lobes/fissures can you see radiologically both anteriorly and posteriorly?
(RML is the medial right border of the heart)
Which lies superiorly, the right or left hemidiaphragm?
Right, it lies 1.5cm above the left due to the liver
True or False: the retrosternal and retrocardiac spaces should be dark on lateral CXR
True, otherwise there is disease present
What can you see anteriorly on CXR?
Which lobe is affected if you can no longer see the right heart border?
Right middle lobe
If you can still see the right hemidiaphragm, which lobe is not affected?
Right lower lobe
Which area is affected if you can no longer see the left heart border?
Lingula
What causes lobar collapse?
Obstruction of the lobar bronchus due to tumour, aspiration of foreign body etc.The lobe supplied by an obstructed bronchus is no longer ventilated and its air gets resorbed. As the affected lobe loses volume it begins to collapse, like a balloon deflating.
What happens with LUL collapse?
- As the lobe collapses, the left oblique fissure is pulled anteriorly. A well defined lobar edge becomes visible on the lateral view
- The collapsed lobe abuts the left heart border which becomes obscured on the PA view.
- Other PA signs include attenuation of the x-ray beam throughout much of the left hemithorax, seen as a ‘veil like’ opacity and reduced left lung size
What does RUL collapse look like?
Bronchial malignancy
What does a pleural effusion look like on erect CXR?
dense pleural fluid is seen to collect at the lung bases and often forms the curved appearance of a ‘meniscus’ at the lung edges
What would you look for with a pneumothorax on CXR?
look for a dark crescent without lung markings bounded medially by the lung edge. It is often at the lung apex.
What would you look for with a tension pneumothorax?
A large air filled unilateral pleural space. With a right sided one for eg, this displaces the mediastinum to the left and depresses the right diaphragm. The collapsed right lung is squashed against the heart.
Where should the tip of a endotracheal tube be placed?
about 2cm proximal to the carina
(The tube below has been inserted too far and has passed into the right main bronchus. There is early collapse of the unventilated left lung)
It is easier for foreign bodies such as this tube to pass into the right main bronchus rather than the left because there is a more obtuse angle between trachea and right main bronchus.
Once carried out the initial checks, what steps should you go through when interpreting a CXR?
- Trachea
- Central?
- Deviated by collapse? (towards lesion)
- Tension pneumothorax? (away from lesion)
- Mediastinum: 3 things normally visible on left border:
- aortic knuckle
- pulmonary outflow tract
- left ventricle
- may be shifted towards collapsed lung or away from process which increases lung volume (e.g. an effusion)
- Hila
- Symmetrical – size & density
- Calcification
- Heart
- ½ of width of thorax
- 1/3 lie to right, 2/3 to left
- Diaphragm
- Right side often higher – liver
- Costophrenic angles
- Any consolidation (pneumonia)?
- Any lobar collapse?
- Any pneumothorax?
- Any TB or masses?
- Any hilar lymphadenopathy?
- Bilateral hilar enlargement?
- Ring shadows of bronchiectasis?
- Pulmonary oedema? (ABCDE)
- Asbestos bodies?
- Lung hyperinflation (COPD)?
RLL pneumonia
Tension Pneumothorax (of the right side)
Normal CXR
Normal
Left pneumothorax
Right middle lobe pneumonia
Misplaced NG tube in the right main bronchus
Right lower lobe consolidation
Benign calcified granulomas
In a CT, where does the contrast go in?
The SVC, so can follow the SVC into the RA
Big white perfect circle on CT with contrast?
Aortia
