Radiology Flashcards
Where does a plain abdo film extend to?
Lung bases to pubic symphysis
System for plain abdo film reporting?
4 solid organs - liver, spleen, pancreas, kidneys (over psoas muscle)
4 hollow organs - stomach, small bowel, large bowel, bladder (gall and normal)
4 other things to check for - lung bases, bones, calculi, free gas and hernial orifices
NB aortic/splenic artery calcification normal
What are the only times you would see the spleen or the pancreas?
Spleen if enlarged
Pancreas if calcifies
Most common axis for the stomach to twist on in volvulus?
Organoaxial due to hiatus hernia
How to distinguish small bowel loops vs large bowel loops?
Small bowel: lines () go all the way across, lots of it, central.
Large bowel: bigger? lines only extend 2/3s of the way across, outside of centre - fixed at splenic flexure and hepatic flexure
‘Gas filled viscus’ if unsure which
What is thumb-printing?
Oedematous bowel wall - gas trapped in lumen hence shape around edge.
Causes of oedematous bowel wall?
Infection/inflammation/ischaemia/infiltration due to malignancy etc
What to consider if massive massive colon?
Pseudo-obstruction (?laxative abuse)
Common places for large bowel volvulus?
Caecal and sigmoid
Where might abnormal gas be?
NB beware no gas within bowel is not normal either.
Can do a lateral xray to check for free gas.
Intraperitoneal - NB meniscus if gas in stomach to help differentiate/ nb can see lung markings behind/look nder liver.
Retroperitoneal - Riglers sign?
Biliary tree - rare - emphysematous cholecystitis associated with diabetes. OR gas after a stone passed.
Urinary - iatrogenic.
Abscess
What does free gas look like in comparison to bowel contained gas?
Quadrilateral shapes.
Normal vs pathogenic calcification?
Normal - lymph nodes, fibroids, phleboliths
Pathological - renal/biliary/vascualr/bladder.
Systemic approach to CXR?
Details
View
Adequately inspired/exposed?
Heart - aorts - hilum - long zones - diaphragm - gas elsewhere - ribs/bones
Where does the 50% of the chest rule for the heart apply?
50 % of GREATEST trans thoracic diameter
What is peri bronchial cuffing?
Fluid tracking before florid pulmoary oedema
What helps distinguish pneumonia types?
Peripheral/zones vs per-hilar
Why does TB prefer apical ZONES of lungs?
Less oxygen
What common disease gives rise to chronically flat diaphragms?
Emphysema
What is the lingula?
RMV equivalent
What would you see on a CXR if pneuomothorax?
Flat diaphragm, vertical R bronchus, mediastinal shift - reveals vertebral bodies/widening.
What is the deep sulcus sign?
Costophrenic deepening, often only see flattened diaphragm
Rib fractures on CXR?
Consistently underestimated.
How to tell if fluid is in a vacuum or not?
Meniscus = vacuum
How can you see the difficult LLL collapse common after cardiac surgery?
Look at medial end of hemidiaphragm. Can you follow hemidiaphragm to the aorta? If not could be LLL collapse mimicking heart border.
Also, left hilum lowers/vessels on the left move.
What is the sail sign?
Big thymus in kids?
What does hilar lymphadenopathy show?
Sarcoid or malignancy (should be concave not bulging)
If an US is lower frequency what does that mean?
Higher penetration, lower resolution picture
When do you use linear not curved US probes?
For carotid dopplers/nerve blocks etc
What things in US are very reflective of sound?
Gas and stones
Fat
(All v white)
How to tell the difference between gas and stones on US?
Gas: lines echoing behind (ringdown?)
US landmark for pancreas?
SMA coming of aorta
Early and late signs on US of biliary obstruction?
Early - dilated CBD (if no gall bladder 10-12mm acceptable)
Late - visible/dilated intrahepatic ducts
Where do you look for free fluid in the abdomen?
Morrison’s pouch (potential space between R kidney and liver) NB also on left - spleen
Signs of hydronephrosis on US?
If can see black collecting system around fatty medulla of kidney
How to measure aorta for aneurysm?
AP: look up cut offs but 5/5.5cm for surgical fixing.
Pelvic US - instructions to patient?
Full bladder: to move bowel out the way
What used to be common first-line imaging in major trauma?
CXR, pelvis, lateral c-spine, plain abdominal film
What are you looking for in major trauma in mediastinum?
Superior mediastinal contours for aortic injury, mediastinal widening - rupture.
What is the deep sulcus sign?
Deep costophrenic angle
Why do people die of tension pneumothoraces quickly?
Increase in thoracic pressure causes kinking of SVC/IVC -> VF > Death.
What views for a C-spine xray?
CTLV -> inferior lateral -> AP -> obliques - to get cervical/thoracic junction.
Where are most C-spine injuries?
50% are in the cervical-thoracic junction.
50% are in the base of C2 (?)
Structure for assessing c-spine xray?
Anterior v line; odontoid peg in the vertebral body of C2; interlaminar/spinolaminar line; spinous processes line (aka curvature - NB not C1); Soft tissue anterior area in adults - common area to develop a haematoma.
What is the mechanism for a C1 compression injury?
Occipital condyles press against C1 body, if the ligament is torn then this leads to the connection with C1 and C2 being lost.
What is a Jefferson fracture?
Fracture through the anterior and posterior arches of C1; mostly due to axial loading - hyperextension injury. Stability is dependent on the integrity of transverse ligament. Lateral masses are displaced laterally as transverse ligament if torn.
C2 fracture of odontoid peg - how many types?
Type I: stable - above ligament
Type II: below peg
Type III: through entire body
C2 fracture of odontoid peg - what is seen on x-ray/how do they present?
Lack of alignment in anterior line/present late holding head - wobbly.
What is a Hangman’s fracture?
Fracture of pars interarticularis/both pedicles.
C2/3 posterior relapse.
If unstable then the posterior ligament is ruptured -> anterior displacement due to chip of vertebral body.
Stability rule for vertebral fractures?
If more than one out of three columns if affected
What is the cause of locked facets?
Lateral blows/hyperflexion (like a tiled roof when flex, jams up)
What are the signs/problems associated with 1 vs bilateral locked facets?
1: malrotation is biggest problem. Look for transverse processes on AP film.
Bilateral: translocation of vertebral body on lateral film. (movement of the v body forward)
Pelvis - blunt trauma and haemorrhage - what can we do?
Embolisation.
