CAT scans, MRIs and Herniations Flashcards
CT scans key points
has ionising radiation radiation is absorped to make image- > density > whiteness Bone window or soft tissue window take transverse sections ST will show bone has hyperintense
Positivesof CT scan
good for bone fragments, good for calcified structures, haematomoas, disc injuries,
Negatives of CT scan
high radiation, contrast media can be contrainidcated, claustrophobia
Disc herniation regions
Central- usually prevent by PLL
Paracentral- most common, it will compress the TRAVERSING spinal nerve root not the EXITING (e.g L5 disc herniation, S1 nerve root)
Intraformanial zone herniation: rare
Extraforaminal hernination zone: very rare
MRI key points
t1= fat study t2= water (think alphabetical) 3 views: coronal/ frontal, axial/ transverse, sagittal/ lateral T1: spinal cord, skin, bone, T2: CSF, effusion, oedema
MRI advantages
multiplanar non-ionising can use contrast media optimum for IVD high sensitivityadn specificity
MRI disadvantages
large patients dont fit, claustrophobia and long immbolituly, expensive, cant have pacemaker
overused
Proton density scan vs stir
will see both water and fat
stir will supress fat and enhances water in all tissues
Fat saturation study
suppresses fat signals, you wont see any subcutaneous fat in the scan. increases definition of tendons and ligaments, and visualisation of water, x
COmmon herniation sites
95% in L4/5/S1
then L3/4.
Cervicals C6/7, then C5/6
Degenerative disc
reduced water content= dessicated. on T2 MRI it will not be grey in the area where the disc should be
loss of disc height
Traumatic disc
flexion rotation mechanism, damage to annulus fobrosis will result in herniation.
Tests for disc
SLR: shows if L5 S1 are affected,
Crossed SLR:
Prone knee bend: L2,3 4
Slump
Treatment of disc
bed rest for no more than 2 days Exercise programs Cortisone injection or local anaestethic Laminectomy- Microdisectomy: removal of the iside of the disc to preent reherniation
Imaging for dsic
- MRI, 2. CAT, 3. X-ray
x-eay: decreased disc height,
