Radiology Flashcards
Primary signs of fracture on XR
Cortical disruption
Lucency
Impaction sclerosis (esp on weight bearing bones)
Secondary signs of fracture on XR
Lipohaemarthrosis
Haemarthrosis
Soft tissue swelling
Common problems with AP CXR
Mediastinum is widened
Rotation usually in play due to difficult positioning
Poor inspiration esp if flat or intubated
Lateral CXR features
Labelled by side that is closest to cassette
L hemidiphragm has stomach bubble directly under
L oblique fissure more vertical than R
R hemidiaphragm wider than L on L lateral film
R hemidiaphragm complete. L hemidiaphragm incomplete due to cardiac silhouette
Can use lateral decubitus if concern for effusion or PTX and no other imaging modality available. If ?PTX place this side up, if ?effusion, place this side down for best visualisation
CXR assessment of adequacy
Inspiratory effort - 6 anterior ribs on R
Rotation
Angulation - clavicles should overlie posterior 3rd rib
Penetration/Exposure
Poor inspiratory effort CXR - complications
Enlarged mediastinum
Crowding of vessels at lung bases
Rotation on CXR - complications
Hypertranslucecy of ipsilateral lung
Pseudomediastinal mass on R rotation
Aortic arch widened appearance on L rotation
CXR angulation
Craniocaudal beam divergence
Clavicles should project over posterior third rib
CXR penetration
Thoracic vertebrae should be just visible on a PA CXR
Underpenetration common in mobile AP films due to battery power
CXR over penetration complications
Harder to see subtleties
CXR under penetration complications
Pulmonary vessels and interstitium appear more prominent
Detail is lost at the lung bases and the vertebrae
Lung zones
From anterior rib 2 up = upper zone
Ribs 2-4 = midzone
Rib 4 to diaphragm = lower zone
Silhouette signs on CXR
Objects of similar densities will lose their margins when touching each other
RUL forms silhouette with medial pleura of R mediastinum
RML silhouettes to RHB
RLL silhouettes to diaphragm
LUL to LHB and aortic knuckle
LLL to L diaphragm
Silhouette sign CXR pitfalls
Pectus excavatum can cause loss of RHB
Pericardial fat pads
ETT on CXR
Should be 4cm above carina
Can move up and down by 2cm with neck flexion and extension
CVL on CXR
Should be at junction between SVC and RA
Subclavian line may migrate caudally to internal jugular instead of to SVC - increased risk of thrombosis due to decreased size of IJV compared to SVC
If too long can land in RA or RV and cause arrhythmia
Swan-Ganz catheter placement check on CXR
In pulmonary artery - between main pulmonary artery and interlobar artery
Forms a loop on CXR
Should be no more than 2cm from cardiac silhouette
NGT should be at least 10cm past GJ junction at T10
Pacemaker placement check on CXR
Single chamber - RA or RV
Dual chamber - RA and RV
Biventricular or three lead pacemaker - RA, RV and coronary sinus
ICD lead is thicker than pacemaker
RA lead should be anterosuperior on lateral CXR, RV lead should be anteroinferior
Check the leads have a direct course, no fracture and neither taut nor slack
Heart position on CXR
1/3 to the right and 2/3 to the left
RV anterior heart border on lateral CXR
Posterior HB on lateral is LA + LV
Size can vary by 2cm based on insp/exp and systole/diastole
LA enlargement gives subcarinal angle >100’ and a double atria shadow + posterior bulge on lateral
LV or RA enlargement gives prominence of the heart border
RV enlargement appears as filling of the retrosternal space
Signs of pericardial effusion on CXR
Globular heart shape
Straight, well defined heart border
Rapid increase in size
Signs of LHF on CXR
Enlarged mediastinum
Upper lobe diversion
Pleural fluid/increased interstitial markings/Kerley B lines - followed by airspace opacification
Pleural effusion - R precedes L, usually bilateral
L mediastinal borders
LBH:
L subclavian vessels
Aortic knuckle
L pulmonary artery
Auricle
LV
RHB:
R brachiocephalic vessels
R SVC
RA
IVC (not always visible)