Lecture MRI Spine

Bone marrow changes: 1- Type I: edema 2- Type II: fatty ( white in T1) 3- Type III: bone sclerosis (like bone cortex black in T1 & T2) Degenerative marrow changes: If bony end plate is white in T1  fatty [as it 's not seen in T2] If bony end plate is black  sclerosis

1- Hypertrophy (developmental spinal canal stenosis) 2- calcification   1- Hypertrophy (developmental spinal canal stenosis) 2- calcification 3- ossification  .Calcium deposition: is more seen in CT than in MRI as ca is black in both T1&T2 . Buckled ligamentum flava : I see if spinal canal is encroached or no. . Ossification of posterior longitudinal ligament: OPL N.B Osteophytes has wide base against vertebra versus ossification has narrow base

1- edema : due to compression by disc (ant) & ligamentum flava (post) 2- early myelomalacia : reversible if edema is treated 3- late myelomalacia : irreversible if edema isn't treated N.B. Both early & late myelomalacia produce focal area (white stain) of low signal in T1 & high signal in T2 so we differentiate by clinical pressure, by history & duration of illness If it's recent edema Not so far early myelomalacia Far  late myelomalacia If there is local lesion in spinal cord without compression another pathology  

Paravertebral soft tissue shadows .Hemorrhage, bone fragments . Abcesses( inflammatory disorders) .Tumor (neoplastic extra osseous mass)

Contrast administration ;DTPA We use it to differentiate between postoperative scar tissue & residual or recurrent disc lesions If it gains dye (becomes white in colour)  scar tissue If it doesn't gain dye  disc lesion If part gains dye & part doesn't gain  so there's both disc & scar tissue

Indications of contrast 1- To detect site of operation 2- To detect degree of thecal decompression 3- To detect post operative complications

N.B. Post operative cervical surgery: There's no contrast administration in cervical spine as the aggressiveness of scar tissue formation in cervical spine is not as in lumbar spine after surgical interference. N.B. Contrast administration from 2 month to 20 years not after that as scar tissue becomes mature & contrast doesn't appear.

Types of surgery 1- spinolaminectomy 2-hemi laminectomy (pore in the lamina & suction of the disc) 3-laminar fenestration minimally invasive ( the lamina of the above vertebra which is removed)

Post operative complications: 1- Scar tissue / disc lesions (scar tissue enhances) 2- Disc space infection 3- Arachnoiditis (adhesion between cauda equina nerve roots) N.B. Perineural scar: scar formation around roots which become compressed  

Differential diagnosis between nerve root & recurrent disc: After contrast administration if we see a black point on one side look at the contra lateral side if there's also another black point so this is a nerve root & if there's not present so this is recurrent disc N.B. Usually the nerve root at site of scar tissue is thick due to compression which leads to swelling

Arachnoiditis: It's diagnosed in axial T2 image never to be diagnosed in sagittal image As nerve roots are black & C.S.F. is white Pseudo cord sign: All nerve roots become adhesive to each other & appear as a cord in the cauda equine level (after L1-L2) Empty thecal sac sign: Nerve roots become attached at the edges of the thecal sac Disc space infection: Hyperemia, fluid, pus, edges of the vertebrae are filled with water In T2 appears white & in T1 appears black

Comparison between degenerated disc and disc space infection . Disc is black in T1& T2 . Presence of osteophytes with bone marrow changes. disc is white in T2 but black in T1 . sclerotic only