Thoracic Imaging: Chest X-Rays Flashcards
when are some instances when you may order a chest x-ray?
(indications)
- acute respiratory/cardiac disease
- major chest trauma
- hemoptysis
- dyspnea
- post tube/line insertion
- suspected mass, LAN, metastisis
- suspected PE, Pulmonary edema, CHF, PNA, Pleural effusion, PTX, TB
when would you NOT get a chest x-ray
- routine following pneumonia
- no clinical change in ICU pts.
- minor chest trauma (rib fracture)
- URTI
- lung cancer screening (get CT)
- acute asthma (isnt going to help clinical decision making)
what are the 4 parts of adequacy for a chest x -ray
- penetration
- rotation
- magnificaion
- angulation
what is penitration of an x-ray ?
how do you determine if its proper penitration on an x ray ?
what is over and under penitration?
penitration:if the appropriate amoutn of radiation was used to caputre the image
you should be able to see the throacic spines through the heart shadow
over-penitration: the lung markers will be decreased or absent (look too black)
under-penitrated: unable to see the sping through the heart (too light)
what is rotation of the x ray?
how is it determined?
rotation: the film should be perpendicular to the pt.
check that the medial ends of the clavical are centered around the spinous processes of the vertebrae
slight rotation may be ok depending on the pt. and the study
but tii much can alter the size and visability of specific things in the thoracic cavity
what is angulation of the x-ray?
how do yu determine if there is proper angulation?
think rib counting! should see the 3rd rib intersect with the clavicle
sometimes the pt. is just kyphotic (curved) or slumped in bed!!
what is adequate inspiration for an x-ray?
what can you do to determine adequate inspiration?
why might there be poor inspiration?
poor inspiration: the lungs will be compressed and the lung markings will be crowded (take a deep breath before!)
- can be due to LOC, poor effort, mechanical restriction of the lungs (disease, pregnancy, obeset, laying in bed)
count the ribs on image – should see about 7-10
what is magnification on x-ray?
what directions (AP, PA) will produce bigger or smaller shadow
magnification: the size of the heart will change depedning on which way the x-ray was taken
AP: anterior-posterior (the emitter is in the anterior – heart is closer) therefore the shadow of the heart will appear larger
PA: posterior-anterior (the emitter is in the back commonly how its done standing)
the heart shadow will be smaller
how is cardiomegaly identifed on xray?
- AP? PA?
- PA film: if the heart covers > 50% of the thoracic rib cavity = cardiomegaly
- AP film: if the left heart border is touching the left chest wall = cardiomegaly
not diagnostic but signs pointing towards
how will atelectasis appear on imaging?
Atelectasis: a collapsed lung (or lobe of the lung!! (not due to a buildup of air in the pleural cavitiy– but a lost of air within the lung itself)
-loss of air inside the lung –> lung will appear white on imaging
-increased densitiy of the lung
- a shift of the mediastium (the bronchi and tracha) towards the side of the atelectasis)
- sail sign the collasped lobe ( LLL)
usually due to an obstruction in the airway (mucus plug, obstruction, tumor, FB)
-inhibition prevents inhaliation but may allow air to escape
How will a pneumothorax present on imaging?
pneumothorax: air in the pleural cavity
- identified as losing the lung vasculature markings in areas where the lung should be
- seeing the “outline” of the lung, visceral pleura not at the full inspiration it should be at (towards the chest wall)
- tension pneumothorax does not require xray since its life threatening –> you will commonly see a shift of the mediastinum away from the side of the pneumo. as the air is creating pressure
what are airspace diseases? what are intersistial diseases? how are they different
airspace disease: a disease of the airways within the lungs – the alveoli
- some disease process takes up the airspace (which should be darker on image) become consolidated
- seen in pneumonia, hemorrhage, pulmonary edema, aspiration (things in the airway!)
interstitial disease: disease of the lung paryenchyma itself (the interstitum, walls of the alveoli or the capillary walls)
- described as infiltrative
- seen in idopathic pulm. fiberosis, scleroderma, bronchogenic carcinoma, sarcoidosis
how will airspace diseases appear on xray? what are some descriptors?
- airspace disease appears “fluffy” or “cloud-like” consolidations on imaging
- there are no sharp borders/hard lines unless it is the edge of a lung lobe, etc.
- air bronchiograms areas where usually the bronchi would not be seen (as the entire lung is mostly black) but when the alveoli are conslidated (look white) the bronchi appear to stick out on imaging
- silhouette sign usually each thing should have its own borders, easily identifiable but a silhouette sign is when two strucutres share a border (like the heart and a tumor)
how will interstital lung diseases appear on xray? what are some descriptors?
- reticular: networks of lines (inflammed connective tissue)
- nodular: assortment of dots
- reticulonoldular: a combo
- will not see airbronchiograms and will not be uniform in appearance
how will a pleural effusion appear on imaging? different reasons for transudative v exudative effusion?
transudative: think fluid overload due to imbalance in osmotic pressure
- CHF, liver dz, renal dz.
exudative: higher in protein – think cancer or infection
- malignancy
- empyema
- hemothorax
- chylothorax
imaging
- appear with a minuscus shape
- blunted costophrenic angle
- can be loculated – in that fluid gets trapped in pockets between fiberosis septal lines
