Chest Masterclass Flashcards
how does X ray make an image?
compares densities
- more dense = whiter
less dense = darker
process of interpreting an X ray?
check name and CHI is there a side marker? is it technically accurate - projection - inspiration - rotation - penetration
PA radiograph?
…
normal cardiothoracic ratio?
<0.5
how is cardiothoraciC ratio (CTR) measured?
PA x-ray
not AP as objects close to the x ray tube are enlarged so the heart would look bigger on AP
why is a large inspiration in CXR important?
to see at least 6 ribs
can look like pathology of not fully inspired
how can you tell if CXR is centred?
medial ends of clavicles are equal distance from spinous processes
mediastinal borders on CXR?
aorta pulmonary artery left auricle left ventricle right atrium trachea hemidiaphragm stomach bubble horizontal fissure - should all be seen on CXR
what are pulmonary hila?
junctions between the heart and lungs
where the pulmonary arteries and bronchi enter and the pulmonary veins exit the lungs
mainly arteries (veins small)
which hilum generally sits higher?
left
- come out above the bronchus which the right comes out below
normal difference in diaphragm height?
right side 1.5cm higher
zones of lungs?
not same as lobes lungs divided into - upper (to 2nd rib) - middle (2-5) - lower (below 5) should be roughly same size
review areas/
ares where things are missed
- lung apices (masses etc)
- behind heart (consolidation etc)
- below diaphragm (gas bubbles, gastic things etc)
- bones and soft tissue
lingula is found in which lung?
left lower lobe
what causes lobar collapse?
blockage in bronchus (lobe supplied by obstructed bronchus isnt ventilated and its air gets reabsorbed so lobe looses volume and collapses)
signs of lobe collapse?
reduced volume in lung
- sail sign
- higher diaphragm
how does upper lobe collapse present?
collapses forward against anterior chest wall
heart becomes less visible
volume loss causing higher diaphragm etc
“veil like opacity” in upper lobe
how does middle lobe collapse present?
smallest lobe so not much volume loss seen
obscuration of righ atrium loss of clarity of right heart border
preservation of the diaphragm on that side
what can cause collapse of middle and lower right lobes?
blockage in bronchus intermedius (common bronchus which splits to supply air to middle and lower lobes)
how does consolidation present?
diaphragm preserved
may have clouding of other mediastinal features but no volume loss?
air bronchograms?
tubular outline of an airway made visible by filling of the surrounding alveoli with fluid/exudate etc (e.g from infection)
specific for consolidation?
should pleural cavity be visible if normal?
no
when is pleural cavity seen?
pleural effusion
- fluid gathers at lung bases if upright and often forms curved meniscus sign (blunt costophrenic recess)
pneumothorax
larger pleural effusion?
more homogenous
meniscus sign tracks against the lobes
what is seen in pneumothorax?
clear black crescent overlying edge of lung markings
clear black area surrounding lung if larger
(lung edge should not be visible in normal lungs as stuck to pleura)
how does large tension pneumothorax present?
large air filled space displaces mediastinum and trachea
heart can be pushed over to other side
signs of pulmonary oedema (heart failure) in order?
- dilation of upper lobe vessels and right side of heart (then left side)
- upper lobe veins should be pencil thin and hard to see) - interstitial opacities (fluid overspills into interstitium which supports the lungs)
- airspace opacification (alveoli causing cotton wool appearence, perihilar/batwing effusion)
- pleural effusion
ABCDE of heart failure signs?
alveolar bat wings kerly B lines cardiomegaly dilated upper lobe vessels edema
tubes which may be seen on CXR?
endotracheal tubes
-normal = 5cm abover carina, 2/3 width of trachea, balloon cuff should not expand trache
- abnormal = tip extends past carina inot right main bronchus, may enter oesophagus)
nasogastric tube
- normal = in subdiaphragmatic position in stomach (overlying gastric bubble on CXR), 10cm beyond gastro-oesophageal junction
- abnormal = tip in oesophagus, bronchus/lung, coiled un upper airway, intracranial in case of skull fracture
Central venous catheters
- inserted via right or left internal jugular or subclavian veins but has to enter right side SVC
- 2nd intercostal space is normal place of tip
- abnormal = too high in proximal SVC
- ……..
what might malpositioned endotracheal tube cause?
lung collapse
if too far into right bronchus, only right lung will be inflated
nodule classification based on size?
miliary nodule = <2mm
pulmonary micronodule = 2-7mm
pulmonary nodule = 7-30mm
pulmonary mass = >30mm
distribution of pulmonary nodules?
perilymphatic
centrilobular
random
morphology of pulmonary nodules?
solid
partly solid
ground glass
primary lung cancer tend to be where?
apical (where the smoke does)
metastases = lower (where most blood vessels are)
cancer staging?
TNM
- tumour size
- nodes
- metastases
investigations in suspected lung cancer?
contract enhanced CT - asses size, mets and biopsy guidacne FDG-PET CT - nodal metastases - distant mets - delineating tumour
what is pneumoperitoneum?
perforation of hollow organ results in gas in peritoneal cavity
gas rises up above the diaphragm
seen as a thin black line between diaphragma nd sub-diaphragmatic structures
PE presentation?
dyspnoea pleuritic chest pain cough orthopnoea haemoptysis signs of DVT in leg
PE investigation?
D dimers (can rule out but not confirm) CTPA = gold standard as visualises the clot
PE x ray features?
usually normal or show non-specific findings
only really used to look for alternative causes of symptoms
CTPA features of PE?
clot can be visualised
V/Q scan features of PE?
looks for defects caused by the clot
mis-matched perfusion defect
how might the heart be affected by PE?
enlarged right side as it cant pump blood out against blockage in pulmonary artery
contrast/blood can back up into IVC etc
