Spine Radiology x ray ct mri normal anatomy

8/12/2019 Spine Radiology x ray ct mri normal anatomy

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Spine Radiology

Cervical spine

Thoracolumbar spineX-RAY

CT

MRI


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CERVICAL SPINE Standard views

- Lateral view

- Anterior-Posterior (AP) view

- Odontoid Peg view (or Open Mouth view)

In trauma case these images are all difficult to acquire because thepatient may be in pain, confused, unconscious, or unable tocooperate due to the immobilisation devices.

Additional views

- 'Swimmer's view'

If the lateral view does not show the vertebrae down to T1 then arepeat view with the arms lowered or a 'Swimmer's view' may berequired.


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Systematic approach to interpret

cervical spine xray

Coverage- Adequate?

Alignment-Anterior/Posterior/Spinolaminar

Bones- Cortical outline/Vertebral bodyheight

Spacing- Discs/Spinous processes Soft tissues - Prevertebral

Edge of image


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AP View

Coverage- The AP view shouldcover the whole C-spine andthe upper thoracic spine

Alignment - The lateral edgesof the C-spine are aligned (redlines )

Bone- Fractures are moreclearly visible on lateral view

Spacing- The spinousprocesses (orange) are in astraight line and spacedapproximately evenly

Soft tissues- Check for surgicalemphysema

Edges of image- Check forinjury to the upper ribs andthe lung apices forpneumothorax


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Lateral viewthe most informative image

Coverage- All vertebrae are visible from the

skull base to the top of T1/T2 (If T1 is not

visiblerepeat image with the patient's

shoulders lowered or a 'swimmer's' view may

be necessary

Alignment- Check the Anterior lineGREEN

(the line of the anterior longitudinal ligament),

the Posterior lineORANGE(the line of the

posterior longitudinal ligament), and the

Spinolaminar lineRED(the line formed by the

anterior edge of the spinous processes -

extends from inner edge

of skull).

Bone- Trace the cortical

outline of all the bones

to check for fractures


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Lateral

Bone- The cortical outlineis not always well definedbut forcing your eye aroundthe edge of all the boneswill help identify fractures

C2 Bone Ring- At C2 (Axis) thelateral masses viewed sideon form a ring of corticatedbone (red ring )

This ring is not complete in all

subjects and may appear asa double ring

A fracture is sometimes seenas a step in the ring outline


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Lateral view Disc spaces- The vertebral bodies are

spaced apart by the intervertebral discsThese spaces should be approximatelyequal in height

Prevertebral soft tissue- Somefractures cause widening of theprevertebral soft tissue due toprevertebral haematoma

- Normal prevertebral soft tissue(asterisks) - narrow down to C4 and

wider below- Above C4 1/3rd vertebral body width

- Below C4 100% vertebral body width

Note:Not all C-spine fractures areaccompanied by prevertebralhaematoma - lack of prevertebral soft

tissue thickening should NOTbe takenas reassuring

Edge of image- Check other visiblestructures


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Odontoid peg /Open mouth view Its primary purpose is to view

lateral mass alignment.

If a fracture of the odontoid

peg (dens) is presentoftennot visible with this view. If apeg fracture is not visible, butis suspected clinically by a

senior clinician, then furtherimaging with CT should beconsidered.


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Open Mouth view-

cont.

This view is consideredadequate if it shows thealignment of the lateralprocesses of C1 and C2(redcircles)

The distance between the pegand the lateral masses of C1(asterisks) should be equal oneach side

Note:In this image theodontoid peg is fully visible

which is not often achievablein the context of trauma dueto difficulty in patientpositioning


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Swimmers viewIf the lateral view does not show the vertebrae down to T1 then a repeat view with the arms

lowered or a 'Swimmer's view'may be required.

This is an oblique view whichprojects the humeral heads awayfrom the C-spine.

A swimmer's view may be usefulin assessing alignment at the

cervico-thoracic junction if C7/T1has not been adequately viewedon the lateral image, or on arepeated lateral image with theshoulders lowered.

The view is difficult to achieve,and often difficult to interpret. Ifplain X-ray imaging of the cervico-thoracic junction is limited thenCT may be required.


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Swimmers view- cont.

Oblique image with the

humeral heads projected

away from the C-spine

The cervico-thoracicjunction can be seen

Check alignment by

carefully matching the

corners of each adjacentvertebral body -

anteriorly and posteriorly


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Thoracolumbar spine

Standard views

- AP

- Lateral

Systematic approach- Coverage - Adequate?

- Alignment - Anterior/Posterior/Lateral

- Bones - Cortical outline/Vertebral body height

- Spacing - Discs/Spinous processes/Pedicles- Soft tissues - Paravertebral

- Edge of image

Coverage The whole spine is


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Thoracic s Lateral and AP Coverage- The whole spine is

visible on both views (T1 till T12)

Alignment - Follow the cornersof the vertebral bodies from one

level to the next

Bones- The vertebral bodiesshould gradually increase in sizefrom top to bottom

Spacing- Disc spaces graduallyincrease from superior toinferior

Soft tissues - Check theparavertebral line (in AP image)

Edge of image - Check the otherstructures visible

L l (i d il)


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Lateral (in detail)

Alignment - Vertebral body alignmentis assessed by carefully matching theanterior and posterior corners of thevertebral bodies with the adjacentvertebra

Bones - Gradual increase in vertebral

body height from superior to inferior

Spacing - Disc spaces graduallyincrease in height from superior toinferior

VB = Vertebral body

P = Pedicle

SP = Spinous process (ribs overlying)

F = Spinal nerve exit foramen

AP (i d il)


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AP (in detail) Alignment- The vertebral bodies and

spinous processes (SP) are aligned

Bones- The vertebral bodies and pediclesare intact

Other visible bony structures include the

- transverse processes (TP)

- -ribs- costovertebral and costotransverse joints

Spacing- Each disc space is of equal heightwhen comparing left with right. The pediclesgradually become wider apart from superior

to inferior

Soft tissue - Note the normal paravertebralsoft tissue which forms a straight line on theleft - distinct from the aorta


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Lumbar s Lateral Coverage - The whole L-

spine should be visible

Alignment - Follow thecorners of the vertebralbodies from one level tothe next (dotted lines)

Bones- Follow the corticaloutline of each bone

Spacing- Disc spacesgradually increase in heightfrom superior to inferior -Note: The L5/S1 space isnormally slightly narrower

than L4/L5


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Lateral (in detail)

Check the cortical outline of

each vertebra

The facet joints comprisethe inferior and superiorarticular processes of eachadjacent level

The pars interarticularisliterally means 'part

between the joints'- P = Pedicle

- SP = Spinous process

L spine Normal


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L-spine - NormalAP

Alignment- The vertebralbodies and spinous processesare aligned

Bones- The vertebral bodiesand pedicles are intact

Spacing - Gradually increasingdisc height from superior to

inferior. The pedicles graduallybecome wider apart fromsuperior to inferior - Note: Thelower discs are angled awayfrom the viewer and so are less

easily assessed on this view


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L-spine - Normal

AP


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L-spine AP (detail)

Check carefully for pedicle integrity andtransverse process fractures


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Three column model -

Fracture Anterior column = Anterior

half of the vertebral bodiesand soft tissues

Middle column = Posteriorhalf of the vertebral bodiesand soft tissues

Posterior column = Posteriorelements and soft softtissues

Three column


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Three column

model

Injuries 1 and 2 affectone column only andare considered 'stable'

1 - Spinous processinjury

2 - Anteriorcompression injury


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Injuries 3 and 4 affecttwo or more columnsand are considered'unstable'

3 - 'Burst' fracture

4 - Flexion-distractionfracture - 'Chance'type injury


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CT scan of spine Up to 20 % of fractures are missed on conventional radiographs.

The advantages of CT are:

1. CT is excellent for characterizing fractures and identifying osseouscompromise of the vertebral canal because of the absence ofsuperimposition from the transverse view.

2. CT provides patient comfort by being able to reconstruct images in

the axial, sagittal, coronal, and oblique planes from one patientpositioning.

The limitations of CT are:

1. difficult to identify those fractures oriented in axial plane (e.g. dens

fractures).2. unable to show ligamentous injuries.

3. relatively high costs.


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CT Cervical Spine Axial


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CT Cervical Spine Coronal


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CT Cervical Spine Sagittal


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CT Thoracic Spine Axial


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CT Thoracic-Lumbar Spine

Sagittal


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CT Lumbar Spine Axial


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Zyapophyseal joint= facet joint


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MRI Most sensitive imaging modality in the study of spine disease.


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Difference between T1 and T2 image

T1-weighted image T2-weighted image

Bone marrow Hyperintense/high

signal

(white)

Hypointense/low signal

(black )

CSF Hypointense/low signal(black )

Hyperintense/high signal(white)

Neural tissue

(eg.spinal cord/nerve roots)

Intermediate signal Intermediate signal

Cortical bone Hypointense Hypointense

Intervertebral disc Intermediate signal Hyperintense

(because of the water content)

T1-weighted sagittal,

cervicothoracic spine


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The spinal cord is veryeasily seen.

The CSF anterior andposterior to the cord is

hypointense.

The high signal arising fromthe vertebral body bonemarrow (arrows) is due tothe fat content.

The disk spaces are readilyvisualized and are of lowersignal intensity

T2-weighted sagittallumbar spine


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CSF is now very hyperintense,and the spinal cord appears tohave relatively low signalintensity.

The disks (arrowheads),because of their water content(when normal), appear higherin signal intensity whencompared with the T1-

weighted image. The bone marrow, on the other

hand, is lower in signalintensity .

Lumbar spineT1 & T2


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Axial T2 wtd MRI of cervical spine at C5-C6 level


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Axial T1 wtd MRI of thoracic spine


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Spine Radiology x ray ct mri normal anatomy

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