what are the indications for mri & ct:

What are the indications for MRI & CT:

Disc lesionsPost-operative spine(after surgery)

TumorsAny degenerative disease

TraumaCongenital abnormalities of the spine

• Preparations for CT & MRI:1-Fasting for 4-6 hours2-Contrast material Urographin ,telebrix 1-2 mg/kg

• Administration of contrast:Yes: In post-operative lumbar spine,

inflammatory disorders& neoplastic lesions.No: disc lesions, trauma.AnesthesiaUsed with children & uncooperative patients.

Patient position: Is usually supine, sometimes side lying, &

rarely prone. How to see:         Scanogram: primitive picture to detect the

site of lumbar spine 

Computed tomography (CT):  . Usual scanning. . Axial slides 2-4 mm.

2 mm in cervical spine / 4 mm in lumbar spine Has bone & soft tissue window. CT screening:. Whole segment of the spine 5 mm in cervical spine, 8 mm in lumbar spine.. Selective Scanning Every 3 mm especially in trauma, also in cervical

disc lesions. N.B:If I want to see one vertebra e.g. L3 I have to take 1

vertebra above (L2 )& 1 below (L4).

CT Myelography:o Is considered as intrathecal contrast injection with

L- puncture needle.o We have 2 windows o Soft tissue & bone window.What are the structures I should evaluate in CT of

lumbar spine:• Lumbar spinal canal diameter normally 13 mm.• Disc lesions.• Others.

• facet, sacroiliac joints & paravertebral soft tissue.

Soft &bone window (CT) LumbarSoft &bone window (CT) Lumbar

1. Lumbar spinal canal diameter:Spinal canal is bony structure, so we see it in

bone window.The spinal canal must be closed (at the level of

pedicles).We measure the AP diameter. Types of canal stenosis:1-Relative:11-12 mm & this doesn’t need operation but it

needs operation if there’s disc. 2- Absolute: 8 -10 mm & it must be operated.

• Disc lesions:We detect it in soft tissue window.

Posterior border of the disc is more important as it has relation to the disc.

The normal posterior border of the disc is CONCAVE.

The abnormal is STRAIGHT OR CONVEX.

N.B:. Normally due to overload ,the disc of L5-

S1 is CONVEX & the abnormal is also convex, so to judge if it’s normal or no look at the next slide if: the posterior border of the disc is convex so it is ABNORMAL.

. The angle of inclination in L5-S1 is more than 30 & the device accept up till 30 only so part of the slide will contain bone & part will contain disc.

Normal CT Lumbar

Disc bulge(CT axial)

NERVE ROOTS

MRI – LUMBAR SPINEM

AXIAL VIEW

FORAMEN

Manifestations of arthritis in any joint: (Spondylosis in spine and osteoarthritis of

other joints)1.Osteophytic lipping.2.Narrow joint space.3.Subarticular bone sclerosis4.Sub cortical pseudo cystic changes.5.Intra articular air.(vaccum phenomena)

Vacuum phenomenaVacuum phenomena

CT of cervical spine

We have 2 types of joints:• Neurocentral joint:Is the articulation between one vertebra above &

one vertebra below which makes the shape of the body of the vertebral end plate .

• Facet joint:Is the articulation between the inferior lip of the

transverse process of one vertebra above with the superior lip of the transverse process of the vertebra below, it’s called Hamburger’s Sandwich.

Arthritis of the neurocentral or facet joint gives the same manifestations of nerve compression due to disc lesion.

Cervical disc in CT:• We see it in soft tissue window .The disc in cervical spine is very narrow so every

slide will contain both disc & bone, therefore there isn’t a slide of pure disc, So we choose the slide which contain more disc for assessment.

. All posterior edges of cervical spine are normally convex.

. See if there’s disc substance protruded than the bone.

. Normal spinal cord picture is kidney shaped.

Item Cervical Lumbar

Slide Width 2 mm 4mm

Neurocentral joint Present Absent

Spinal canal diameter

No diameters, but assessed by vision the spinal cord is kidney shaped & surrounded by C.S.F.

13 mm

Posterior edge of disc

Is usually convex All lumbar discs are concave except L5-S1 is normally convex or flat.

Difference between cervical & lumbar spine in CT

Stages of disc pathology (4 stages)

CT of the spine

CT axial  bone& soft tissue widow

CT machine

MRI CT plain x-Ray

CT– CERVICAL SPINE

AXIAL SAGITTAL

C2-3 INTERVERTEBRAL DISC

DISC

FACET JOINTFACET JOINT

SPINOUS PROCESS

FORAMEN

FORAMEN

AXIAL SAGITTAL

CT- CERVICAL SPINEC-1 SECTION

ARCH OF C-1

DENS

BASE OF SKULL

MASTOID

DISC

SPINOUS PROCESS

CT- LUMBAR SPINEPOST MYELOGRAM

CT– CERVICAL SPINEC- 3 SECTION

AXIAL SAGITTAL

PEDICLE

PEDICLE

LAMINA

AXIAL SAGITTAL

CT-- CERVICAL SPINEC-2 SECTION

CT-- CERVICAL SPINEC-2 SECTION

C-2 SPINOUS PROCESS

C-2 BODY

DEGENERATED

C6-7

CT axial                                 CT sagittal  

PEDICLE PEDICLE

NERVE ROOTS

CT- LUMBAR SPINEPOST MYELOGRAM

Axial

Posterior arch #(CT)

Burst # (CT) axial

   sagittal CT

CT axial section (base of the skull)

FORAMEN

CT- LUMBAR SPINEPOST MYELOGRAM

FORAMEN

CT of cervical spine(sagittal)

CT axial

CT of cervical spine (axial)

CT sagittal 

CT sagittal tear drop # dislocation

Tear drop # dislocation(plain)

THECAL SAC

LAMINALAMINA

CT-LUMBAR SPINEPOST MYELOGRAM

FACET JOINTS

CT- LUMBAR SPINEPOST MYELOGRAM

PEDICLE PEDICLE

NERVE ROOTS

CT- LUMBAR SPINEPOST MYELOGRAM