Radiology Exam 2 63 emily made

When should you use CT w/o contrast?

intracranial hemorrhage

When should you use CT w/ contrast?

suspected tumor, infection, CTA, CTV

When should you use MRI w/o contrast?

usually everything else (stroke, MS, malignancy, infection)

When should you use MRI w/ contrast?

comparison w/o contrast, malignancy, infection

When should you use Ultrasound?

evaluation of carotid arteries, baby brains

gray matter vs white matter on a CT

gray matter appears brighter (cell bodies) than white matter (axons)

epidural hemorrhages

located b/w skull & dura mater

confined by sutures

CAN cross midline

common cause: skull fracture

subdural hemorrhages

located b/w dura & arachnoid

cross suture

CANNOT cross midline, confined to cerebral hemispheres

common cause: trauma, elderly, child abuse

subarachnoid hemmorage

where CSF is (appears bright)

conformed to CSF space surrounding brain common cause: trauma

parenchymal hemorrhages

in the "meat" of the brain; associated with edema

common cause: trauma, hypertension

intraventricular hemorrhages

blood w/in ventricular system; usually from other bleed; can lead to hydrocephalus

intracranial mass

mass effect

phenomenon that occurs when a concussion in the brain compresses surrounding brain tissue

midline shift

occurs when the midline is shifted R or L

causes: inter cranial pressure, TBI, stroke, tumor, abscess

ID Dense MCA & what it suggests

warning sign of stroke on CT

dense = bright

indicative of clot in the middle cerebral artery

What is Diffusion-weighted imaging (DWI) best for?

stroke identification

-highly sensitive for finding recent infarcts

core in CVA

infarcted brain tissue supplied immediately upstream of clot/aneurysm

tissue is DEAD & can't be recovered

penumbra in CVA

ischemic tissue further upstream relative to core

tissue CAN be recovered

clot in basilar artery

*would show between F & A

blockage of MCA

CT of cortical strokes

- loss of gray/white matter differentiation

- both gray & white matter become dark

- acute stroke associated w/ mass effect

- chronic stroke associated w/ atrophy

- first line to determine hemorrhage

unruptured aneurysm

ruptured aneurysm

relationship b/w aneurysms & subarachnoid hemorrhages

ruptured inter cranial aneurysms can CAUSE subarachnoid hemorrhage (aka bleeding into the space b/w the arachnoid & Pia mater

Best modality for compression fractures, instability/flexion/extension imaging

XR

Best modality for acute trauma, osseous injuries

CT

best modality for everything else, evaluates bone but also soft tissues, discs, spinal cord, nerve roots

MRI

spinal trauma imaging criteria

age over 65

history of malignancy

pain lasting 6+ weeks

significant trauma

neurological deficit

what is injury to 2/3 columns called?

unstable spinal injury

anterior column consists of

anterior longitudinal ligament, anterior 2/3 of vertebral body

middle column consists of

posterior longitudinal ligament, posterior 1/3 of vertebral body

posterior column consists of

pedicles, articular facts & facets capsule, lamina, spinous processes, ligamentum flavum, interspinous ligament

spinal cord injury

spondylosis

= osteophytes

hook like projections that develop over time

"extra bone projection"

spondyloisthesis

= translation

movement of superior vertebrae relative to inferior vertebrae

spondylolysis

= defect thru facet joints

degenerative disc disease

dark disc on MRI

herniated vs bulging disc

herniated: disc cracks open & soft inside leaks out

bulging: disc stretches & pushes outward, doesn't open (even distribution throughout)

protrusion of disc

herniation stays at level of the disc

extrusion of disc

herniation extends past level of the disc (cranial & caudal migration)

Discitis/Osteomyelitis

characterized by:

disc space narrowing

endplate destruction

fluid signal at disc

marrow edema

epidural spread of infection

abcess

*MRI best

compression fracture of the spinal column

what is the best imaging modality for MSK trauma?

XR

-want at least 2 views

epiphysis of long bone

metaphysis of long bone

diaphysis/shaft of long bone

location of scaphoid bone & what damage to it can cause

fracture can sever artery --> bone can become osteonecrotic

importance of what/when to do imaging on trauma patients

- follow up = important!!!

- XR can't catch everything

- CT more sensitive for finding small fractures & more views

- MRI used to further evaluate soft tissue & marrow; malignancy detection

comminuted fractures

more than 2 fragments

interarticular (fracture)

whether fracture reaches articular surface (joint)

displacement (fracture)

describes movement of distal fragment relative to proximal

open fracture

whether fracture extends thru skin

*prone to infection; urgent tx

Buckle/Torus fracture

fracture w/o a cortical break

-looks like a bone that buckles in on itself; a telescope

-more common in children

Salter-Harris Classification

used to characterize pediatric fractures thru epiphysis, physis (growth plate), and metaphysis

- higher the classification the higher the risk for complication

Salter-Harris Type 1

fracture through physeal plate only

*may be hard to visualize, look for misalignment b/w epiphysis & metaphysis

Salter-Harris Type 2

physeal plate fracture with metaphyseal fracture

Salter-Harris Type 3

physeal plate fracture with epiphyseal fracture

Salter-Harris Type 4

physeal plate fracture with metaphyseal & epiphyseal fracture

Salter-Harris Type 5

crush injury

shoulder separation

disruption of acromioclavicular joint

shoulder dislocation

disruption of glenohumeral joint

Lisfranc fractures of the foot & why they are important to catch

extremely subtle; located medial cuneiform of 2nd metatarsal

*failure to catch can cause M2-M4 to shift laterally

what kind of imaging is required for septic joint

NONE; if signs up infection --> ASPIRATE