Radiology Flashcards
preferred imaging studies
ct without contrast: trauma, stroke, acute headache, coma
mr without contrast: chronic headache, dementia
mr without contrast: seizure, infection, cancer
facial fractures are commonly caused by ___
blunt or penetrating trauma (vehicle accidents, assaults, falls)
types of fractures
- linear (temporal, parietal)
- depressed (due to direct blow to head)
- diastatic (widening suture lines in childhood)
- basilar
- ping pong (infants)
most common form of traumatic intraaxial injury
cerebral contusion
- at inferior and polar surfaces of frontal and temporal lobes
epidural vs subdural hematoma
read
radiographic features of hematomas
acute = hyperdense subacute = hypo/isodense chronic = hypodense
features of subarachnoid hemorrhage
- ct: hyperdense material in subarachnoid space
- angiography: to see aneurysms (cta, mra, dsa)
- tears of subarachnoid vessels
intracerebral hematomas occur in ___
within brain tissue and due to severe head injury
causes of stroke
infarction: in situ thrombosis (atherosclerosis or embolism)
hemorrhage: hypertension
gold standard imaging for hemorrhage
ct
early signs of stroke
- hypoattenuating brain tissue
- obscuration of lentiform nucleus
- dense mca sign
- insular ribbon sign
benefits of mri for stroke
- can contrast hemorrhagic and ischemic
- diffusion weighted imaging: most sensitive sequence for stroke imaging
screening assessment for head injuries
read (noncontrast ct)
imaging of choice for cervical spine injuries
plain films
lines that should be parallel and aligned
- ant vertebral bodies
- post vertebral bodies
- spinolaminar lines
- spinous process
most common fracture mechanism in cervical injuries
hyperflexion
fracture from cervical hyperextension
hangman’s fracture
- best on lateral view
- fractures through pars intercularis
- anterior dislocation of the c2 vertebral body
- prevertebral soft tissue swelling
fracture from axial compression
jefferson’s fracture
- axial blow to vertex of head (from diving headfirst)
radiographic features of spinal cord compression
- plain film and ct: not for assessment and cause
- mri: gold standard!! to see spinal canal and contents
imaging of choice for thorax
cxr
- rib fractrues
- pulmonary contusions/ lacerations
- abnormal collections of air
- abnormal collections of fluid
most common blunt chest injury
rib fractures
- 4-9 most common = pneumothorax and contusion
- 1 only = facial fractures
- 1 2 3 = serious trauma, ruptured bronchus
- 10-12 = lacerated liver/spleen
what is flail chest
> /=3 contiguous broken ribs in 2 or more places, moves paradoxically with respiration
most common pulmonary finding in blunt chest injury
pulmonary contusion
pulmonary laceration can result in the formation of a ___
traumatic lung cyst or traumatic lung hematoma
pneumothorax secondary to high intrathoracic pressures from ventilation resulting in rupture of pleural bleb
tension pneumothorax
- midline structures are pulled to contralateral side
signs of pneumomediastinum
- spinnaker sail sign: elevation of thymic lobes due to pneumomediastinum
- continuous diaphragm sign: entire diaphragm is visualized from one side to the other
air appears around heart but does not extend above great vessels
pneumopericardium
streaky air over lateral chest wall or neck
subcutaneous emphysema
- localized: penetrating injury
- diffuse: pulmonary interstitial emphysema
abnormal collections of fluid from lungs
- hemothorax
- chylothorax (lymph)
abdominal radiology tests
- erect cxr
- abdominal x-ray (first line)
- us abdomen
- ct abdomen
imaging for pneumoperitoneum
plain radiograph or ct
bowel related signs of pneumoperitoneum
- double wall sign or rigler’s sign
- telltale triangle sign
peritoneal ligament related signs of pneumoperitoneum
- football sign
- falciform ligament sign (silver’s sign)
- lateral umbilical ligament sign (inverted v)
- urachus sign
right upper quadrant signs of pneumoperitoneum
- lucent liver sign
- hepatic edge sign
- ligamentum teres sign
- morison’s pouch sign
- cupola sign
most common disorder of the urinary tract
renal/ureteric calculi, mostly calcium oxalate
imaging modality for acute cholecystitis
uts
findings in acute cholecystitis
- cholelithiasis
- gb wall thickening >3-5 mm
- pericholecystic fluid
- positive murphy sign
- gb distention
most common cause and imaging for peptic ulcer disease
h pylori infection and nsaid use, uses endoscopy or upper gi series
imaging for appendicitis
uts or ct scan
signs of diverticulitis
- diverticulosis
- pericolonic fat inflammation and inc vascularitis in mesocolon
- symmetrical mural thickening
- phlegmon formation
- free fluid
diagnostics for mechanical obstruction
- xray, ct, uts, or mri
- normal bowels: small bowel <3 cm, large bowl <6 cm, cecum <9 cm
- 80% small bowel obs
abnormal aaa findings
- > 3cm abdominal aorta
- thrombus within aneurysm
- calcification
types of fractures
read
describing fractures by direction of fracture line
- transverse
- oblique
- spiral
- longitudinal
describing fractures by relationship of fragments
- displacement
- angulation (a/p, m/l)
- shortening
- rotation
- impaction, depression, compression
describing fractures by number of fragments
2 = simple >2 = comminuted
uncommon: fatigue, insufficiency, secondary to pre-existing abnormality
