imaging of the lung Flashcards
what is in the lung field
diaphragm and recesses
fissures
hilar region
thoracic cage
what is in the mediastinum
heart
great vessels
trachea
soft tissues
commonly used medical techniques
radiography - plane and special CT MRI ultrasonography nuclear medicine imaging
what is the principle of imaging
body tissues selectively limit the passage of radiation
order of tissues from radiolucent to radioopaque
air/gas fat water/fluid bone metal
order of PA components
posterior - x-ray tube
person
anterior - detector
what position do you take PA from
erect
what position do you take AP from
erect or supine
PA view
normal
heart close to film so undistorted
scapular rotated away from the heart
clavicle cross lung field
AP view
supine
heart magnified
scapula overlaps
clavicles projected above apex
what do you check when you get an x ray
patient details
rotation
inspiration - diaphragm low enough so can see top 9 ribs
AP/PA/lateral/supine
exposure - should be able to see the intravertebral disks behind the cardiac shadow
anatomical things to check on an x ray
airways bones distance of the clavical from the midline is symmetrical fractures circulation diaphragm effusion - check lung edges are sharp - if not fluid angle obtuse if atria are enlarged? lung fields gas bubble in stomach mediastinal shadow aortic knuckle/aorta cardiac silhouette transverse diameter of heart should exceed 50% of thorax any other
pneumothorax
no vascular markings hyperlucent R lung field eg clavicle fracture no lung sounds cause tachycardia
treatment for pneumothorax
chest drain
pleural effusion
fluid in pleural cavity
fluid level in relation to R lobe
right costo-diaphragmatic recess obliterated
lung hilar lymphadenopathy
lymph node masses because of sarcoid or lymphoma
lung spread from carcinoma of uterine cervix
mass in r middle lobe and hilar nodes
pulmonary artery angiogram
special contrast imaging
radio opaque contrast contrast material injected into the pulmonary artery and imaged as pass through arterial tree
oesophagus barium swallow
can see the aortic arch impression
Lt main bronchus impression
left arterial impression
Tomos (CT)
slice
Graphein (CT)
to draw
what does a CT do
x ray tube moves in arc around body image detectors moves in opposite dirn in same arc only axial point in surface signal put into a computer image reconstructed and displayed image viewed from inferior side can see the heart chambers
choices for CT
standard CT, Ct angiography, contrast, windowing, reconstructions
what is a window setting
after scan obtained data is digitally manipulated to reveal different structures in great detail
MR imaging
more details and differentiation is seen
uses magnetic field
depends on alignment of protons of H atoms in magnetic field
radio waves excite protons which flip over
they give measurable energy when they flip back when pulsing is removed
more protons (ie more water) emit larger signal
signals processed by a computer and images are formed
what planes can you do MRI in
sagittal
coronal
axial
T1 weighting
show soft tissues
ventricles of lungs
T2 weighting
fluid filled areas more clearly
ventricular depolarisation
defect in septum
mitral regurgitation
reflux into L atrium
how much radiation does an x ray give
equal to 10 days of background radiation
what causes an expression in the oesophagus
aortic arch, L main bronchus, l atrium
if heart bigger they block the atrium
effect of digital subtraction angiography
make black`
what are the surface markings for the heart
3rd CC 1cm from sternal border
6th cc 1cm from sternal border
2nd ICS/CC 2.5cm from sternal border
5th ICS to apex beat and the midclavicular line
what is cardiac dullness
when palpate where the heart is you cant hear the resonance that you would be able to hear from the lungs
