Imaging of the Chest Flashcards
What is the most common view of the chest taken in clinic or hospital?
a PA view
What are 4 things to consider if a film is adequate?
- adequate breath?
- over or under pentrated?
- anything cut off?
- patient rotated?
How can you tell if it was an adequate breath?
should have 10-11 ribs visible within the lung fields
Why do you need an adequate breath?
inadequate breath will crowd the lung structures and make them look pathologic
If a film looks too dark, is it over or under penetrated?
over
What should you check the bones for on a CXR?
fractures are most common - old or new
lesions are next - lytic or blastic
If you see something that looks like a rib lesion, what is the MOST likely diagnosis?
not a lesion at all - a callous due to a healing fracture - look to see if there are others on the adjacent ribs - it’s almost impossible to break only one rib
What are the most common lesions in older age groups?
metastatic lesions
What is located in the mediastinum to look at on a CXR?
heart, aorta, pulmonary vessels, trachea and esophagus
WHat’s a good rule of thumb for how big the heart should be?
It should be less than half the size of the entire chest
What are some non-pathological things that can make a heart look bigger on CXR?
poor inspiration
supine pictures = AP films in general
What are three reasons for the heart to actually be enlarged?
hypertrophy due to overuse
cardiomyopathy from CV disease, drugs or infection
fluid around the heart
Can you tell what’s making the heart big on CXR?
not really - tissue will look the same as fluid - you need a CT
If you see a slight bulge in the left atrium in the context of no cardiomegaly, what does that suggest?
mitral stenosis
What are the two main worrisome things with an abnormal aorta?
aneurysm or dissection
Can you usually see a diaphragm on a CXR?
You shouldn’t see the diaphragm itself, but you can see where it is based on the lung contour - the only way you’d see it is if there were air under the diaphragm
If you don’t have a sharp border showing the diaphragm, what’s something you should check for? How?
diaphragm paralysis
do inspiration and expiration films or a fluoroscopic evaluation with a sniff test. the diaphragm should move down and if it doesn’t, it’s paralyzed
What does air trapping due to COPD look like on a CXR?
- the lungs will look too dark (radiolucent)
- the lungs will be hyper-expanded
- Flat diaphragm
What’s the most common cause of tracheal deviation?
enlarged thyroid gland
Can you usually see lymph nodes on CXR?
nope - only if they’re enlarged. they’re look like fluffy masses
What are the possibilities when you see lymph nodes on CXR?
metastatic disease
lymphoma
reactive nodes related to infection - TB
granulomatous disease like sarcoidosis
What is the silhouette sign?
basically, you can only see other things on CXR because of the border they make with the air in the lungs. So if there is a border that’s obscured, that means there’s something that’s replaced the air and it also tells you WHERE it is in the lungs
Which lung has three lobes and which has two?
right - three
left - two
What does the left have in stead of a third lobe?
A lingula…it’s basically another lobe, but it isn’t divided by a fissure
If something blurs the left heart border (left ventricle), where is the pneumonia?
lingula
If something blurs the left diaphragm, where is the pneumonia?
left lower lobe
If something blurs the right diaphragm, where is the pneumonia?
RLL
If something blurs the right atrium, where is the pneumonia?
right middle lobe
If something blurs the superior vena cava, where is hte pneumonia?
right upper lobe
If something obscures the aortic knob, where is the pneumonia?
left upper lobe
In addition to the obscured border, what will you often see on CXR in a pneumonia?
air bronchograms -
they’re air-filled bronchoa nd bronchioles that are outlined by disease int he adjacent alveoli, so you’ll see black tubes in the white stuff
Can a CXR tell what’s filling up the alveoli and making them look dense?
nope - pus, fluid and blood all look the same on CXR
What are the two general areas infiltrates can develop in the lungs?
interstiail - between the alvolei or in the alveoli themselves
What does an interstitial infiltrate look like?
lacy, reticular (linear) pattern
What is an interstitial infiltrate associated with?
atypical pneumonia, early CSF and fibrosis
What do alveolar infiltrates look like?
fluffy consolidating patterns, usually with air bronchograms
What is an alveolar infiltrate associated with?
bacterial pneumonia, late CSF or acute respiratory distress syndrome
What are some common CXR findings in CHF?
early pulmonary is intersitial while late pulmonary edema is alveolar
pleural effusions
cardiomegaly
Kerley’s B lines (septal lines)
What will pleural effusions appear as on CXR?
blunting of the costophrenic angles
How can you tell if costophrenic angle blunting is from scarring or from effusion?
do a decubitus view and see if the fluid layers out.
WHat’s the difference between a lung nodule and lung mass?
nodules are less than 3 cm, masses are greater than 3cm
What is the number one thing to do if you’re trying to rule out cancer with a newly found lung mass?
check old films - stability over 2-3 years suggests a benign process
What else can you look for to rule out cancer?
calcifications - coarse, central calcifications suggest a benign process
What should be on your differential when you see multiple nodules in the lungs?
metastatic disease
infeciton
granulomatous disease
What should be on yoru differential when you see a solitary nodule in the lungs?
lung cancer abscess infection - TB or blasto AV malformation Granulomatous disease Benign Granuloma
When you have a patient presenting with chest pain, what is the number one thing on the DDx?
acute coronary syndrome - MI or angina
How is the diagnosis of an acute coronary syndrome made?
EKG and enzymes - not really with imaging
What is the second thing to have on your DDx with chest pain?
pneumothorax
Pneumothorax puts air between what?
hte parietal and visceral pleura
Which PTX is life threatening?
tension - air accumulates and can’t get out, causing increased pressure and vena cava compression/impaired venous return
What will you see on CXR with PTX?
you’ll see a sharp line in the mid lung field, which is the visceral pleura
no lung markings lateral to that line
What percentage of PE are diagnosed before death? What percentage of those diagnosed with PE actually ahve one?
only 30%
less than 35%
What are the non specific signs of PE on CXR?
Hamptom’s hump - a wedge-shaped opacity corresponding to lung infarct
Westermark’s sign - a translucent area
What scans can be used to diagnose PE?
A VQ Scan - nuclear medicine scan with ventrilation and perfusion components; perfusion abnormality with normal ventilation suggests PE
Chest CT angiography is more common now
What is the most common aortic emergency requiring immediate surgery?
aortic dissection
What happens in aortic dissection?
you get a tear in the intimal layer of the vessel, which separates the intima from the media or the adventitia on the outside, which causes a false channel to form in the aorta
What do people present with when they have an aortic dissection?
severe pain with tearing or ripping quality
What are the risk factors for aortic dissection?
HTN is the main one
marfans or ehler-danlos
cocaine use
pregnancy
What will a dissection look like on CXR?
a wide mediastinum
abnormal arch configuration - it will bow way out
pleural effusion L>R
What is the study of choice for diagnosing dissection?
CT
How does CT help in determining treatment for dissection?
If it involves the ascending aorta, they need immediate surgery
if it’s just the descending, the patient can be treated medically - lower HTN and it will often heal on its own
