MSK mri Flashcards
(25 cards)
what is t1w TSE/FSE good for seeing and what tissue gives most signal in this
- bone marrow pathology
- muscle tears (blood appears hypertintense/bright)
- protons from fat
signal in PD FAT sat comes from?
- as signal from protons in fat is saturated, image shows good contrast between cartilage and bone especially
what is a MRI arthrogram and how’s it done, what sequence used
- mri for any joints
- gadolinium and locan anaesthetic injected into joint then scanned
- t1 FS in 3 planes or 3D t1
what do you align the positioning of a shoulder MRI to
glenohumoral joint
PD FS (proton density fat sat) (coronal oblique) good for seeing what in shoulder
rotator cuff tear OR shoulder impingement
remember that extremities have their own coils e.g shoulder coil, wrist coil
for PD FS you always want on in coronal, axial and saggital plane (whether its oblique is dependant on what ur scanning (e.g should requires oblique in those 3 planes but wrist doesnt))
what weighting best identified avascular necrosis of bones and why
t1 weighing (e.g scaphoid fracture leading to AVN)
- low signal seen can indicate AVN due to breakdown of bone from low blood supply
what sequence is additional used to identify synovitis (inflammation of joint)
t1 FS VIBE DIXON post contrast
what is tenosynovitis
inflammation around tendons
compare channel/array used in pelvis and wrist
wrist = 8 channel + wrist coil
pelvis = 18 channel body array
Array coil systems are collections of small surface coils whose signals may be combined but generally feed into independent receiver circuitry.
what sequence is best used to rule out occult (hidden) fracture of hip and in what plane
t1 w coronal
tx/rx knee coil used for knees
which anatomy is the positioning for a knee mri aligned to
lateral femoral condyle
what would a normal and torn ACL look like on PD FS image
normal = dark / hypo intense continuous fibres of intact ACL
torn = bright/ hyper intense oedema (blood) from rupture
menisci appear dark / hypo intense on both PD FS and T1W images, how would you go about identifying a tear then
using t2 w image (fluid leaked from menisci would be bright)
which suppression sequence is used for ankle
STIR (fat suppression)
on a PD FS sequence for the ankle, what would tendonitis look like
thickening and hyper intense (bright) signal around the tendon indicating tendonitis
how can there be tibial bone infants?
sickle cells (moon shaped RBC) get stuck in small blood vessels causing obstruction and iscaemia leading to AVN
what suppression sequence is used for foot mri
STIR (FAT SUPRESSION)
Why is STIR required in feet for example when there is already PD FS
STIR works better at suppressing fat when theres high susceptibility differences between tissue (feet are non uniform in shape)
what anatomy is positioning aligned to in feet mri
acquisitions are orientated to a specific area in food e.g specific metatarsal
what is a plantar plate tear
- fibrocartilaginous ligament connecting metatarsal to proximal phalanx (forming part of MTP joint capsule) tears
how does a plantar plate tear present on PD FS
hyperintense signal seen in region of plantar plate
