Imaging of the thoracic, lumbar & cervical spine

Question 1

lanes and surface landmarks

Answer 1

EAM
Mastoid tip
Occiput
Thyroid cartilage

ASIS
Sternal notch
PSIS
Lower costal margin
Xyphoid sternum

Question 2

Spinal anatomy

Answer 2

The vertebral column has four curvatures, the cervical, thoracic, lumbar, and sacrococcygeal curves.

The thoracic and sacrococcygeal curves are primary curves retained from the original feotal curvature.

The cervical and lumbar curves develop after birth and thus are secondary curves

Primary Curves x2
thoracic and sacrococcygeal
Secondary curves x2
cervical and lumbar

Lordotic Curves- upright spine

Kyphotic Curves- curved spine

Question 3

2 main functions of the spine

Answer 3

Protect spinal cord and protect posture.

Question 4

Spinal stability

Answer 4

The junctions of the
curves create natural
areas of weakness

Question 5

Stable fracture

Answer 5

1 Column

Often managed conservatively

A weight bearing fracture in some cases

Does not usually involve spinal cord injury

Can become multi-column if managed incorrectly

Question 6

unstable fracture

Answer 6

Multi column

Requires correction/surgery

Integrity of spinal cord at risk

Possible instantaneous paralysis

Not a weight bearing injury

Question 7

Common clinical indications

Answer 7

Blunt trauma
Axial loading
Hyper-extension, hyper-flexion
Degenerative change
OA/RA
Congenital cause

Question 8

Lumbar Spine Specific clinical indications

Answer 8

Trauma
Pain (sudden onset or longstanding & increasing)
?osteoporotic collapse
? Bone primary/hot spot
? Osteomyelitis
SI joint lesion

Question 9

L-SPINE AP PROJECTION PATIENT POSITION

Answer 9

• Patient supine on x-ray table
• M-S plane in midline at right angles to the cassette
• Patient’s head on pillow, arms by side
• ASIS equidistant from table top
• Shoulders equidistant from table top
• Hips and knees flexed

Question 10

L-SPINE CENTRING POINT

Answer 10

Central ray vertical to the image receptor
Midline at level of lower costal margin
Expose on arrested expiration

Question 11

TOP TIPS - AP

Answer 11

Spinous processes not in midline of vertebral bodies- Rotation of the spine;
MSP not perpendicular to table top
? scoliosis

Intervertebral disc spaces not clearly demonstrated- ? Excessive lordosis – bend hips and knees;
Angle x-ray beam to different sides of the curve

Question 12

L-SPINE LATERAL PATIENT POSITION

Answer 12

SUPINE: Lay patient on table in the lateral position

M-S plane parallel and middle of axilla coincident with midline of table.

Arms raised and folded over head

Vertebral column parallel to cassette

ASIS superimposed

Shoulders superimposed

Can be done standing/erect too

Question 13

L-SPINE LATERAL CENTRING POINT

Answer 13

Central ray vertical to the image receptor

8-10cm anterior to spinous processes at level
of lower costal margin (L3)

Expose on arrested expiration

Question 14

L-spine image criteria

Answer 14

Bony cortex and trabeculae seen.

Intervertebral disk spaces demonstrated.

Bodies of T12-L5/S1 demonstrated.

Vertebral endplates superimposed.

Cortices at the posterior and anterior margins of the vertebral body should also be superimposed. (No double edges)

The imaging factors selected must produce an image density sufficient for diagnosis from T12 to L5/S1, including the spinous processes.

Question 15

TOP TIPS - Lateral

Answer 15

Vertebral bodies not superimposed- Rotation of the spine; MSP not parallel to table top; ensure hips and shoulders are superimposed

Intervertebral disc spaces not clearly demonstrated- ? Scoliosis – consider turning patient onto opposite side

L5/S1 not clearly demonstrated- Inadequate kVp to penetrate area – consider L5/S1 projection

Question 16

L-SPINE- & ADDITIONAL SPINAL PROJECTIONS

Answer 16

AP L5/S1 projection
PA sacrum
Lateral sacrum
Posterior/anterior obliques
Horizontal Beam lateral
Sacro-iliac joints (prone and posterior obliques)
Lateral flexion and lateral extension
Side-bending APs
Erect spine

1,4,5,7,8,9 can be used for additional lumbar spine views

Question 17

L5/S1 LATERAL patient position and entering point

Answer 17

PATIENT POSITION
Same as lateral L-spine

CENTRING POINT
Central ray vertical to the image receptor
8cm anterior L5 spinous process
PSIS

Question 18

L5-S1 Anteroposterior projection

Answer 18

Patient is supine.
Angling around 30 degrees cranially on this projection allows better visualisation through the L5-S1 disc space due to the lumbar spines natural lordotic curvature

Question 19

SACRUM PA

Answer 19

Patient is prone
Central ray perpendicular to IR then angled caudally 10° -25°
Midway between PSIS
Ensures x-ray beam is 90° to sacrum

Question 20

Sacro-iliac joints

Answer 20

To position patient in order to bring the SI joint 90° to the imaging plate and enable the diverging x-ray beam to pass through the joint rather than across the joint (PA not AP).

Question 21

SACRUM LATERAL

Answer 21

Centered over the sacrum, this view is usually performed under specialist request and helps tovisualise pathology of the sacrumand coccyxNot performed very often

Question 22

Left and right posterior oblique L-spine

Answer 22

To demonstrate the pars interarticularis. Side closest to the IR is demonstrated.

Question 23

Horizontal Beam Lateral Lumbar Spine

Answer 23

To avoid moving the trauma patient and avoid exacerbating their injury and causing potential paralysis

Question 24

Lateral flexion and extension (Lumbar)

Answer 24

To assess the degree of movement/flexibility in the spine with the patient flexed forwards and extended backwards – Specialist orthopaedic request.

Question 25

Erect PA spine (WHOLE SPINE)

Answer 25

To assess the affect of gravity on the scoliosis spine To measure Cobb angle - measurement to assess the degree of curvature

Question 26

Side-bending APs

Answer 26

To assess the degree of flexibility in the scoliosis spine with the patient bending to the L and R, and give an indication of the level of spinal fusion. Performed with horizontal beam Tend to image Lumbar and Thoracic spine separately as apposed to one whole image.

Question 27

Thoracic Spine: T1-T12 Standard Projections

Answer 27

AP LATERAL (turned) Additional Projections Lateral (HBL)

Question 28

Thoracic spine Common specific indications

Answer 28

Trauma Pain ?osteoporotic collapse ? Bone primary/hot spot ? Osteomyelitis ? Arthropathy Orthopaedic follow up

Question 29

T-SPINE - AP PROJECTION PATIENT POSITION:

Answer 29

Patient supine with legs straight M-S plane in midline at right angles to the cassette Upper edge of IR at level just below prominence of thyroid cartilage Patient’s head on pillow, arms by side Shoulders equidistant from IR ASIS equidistant from tabletop

Question 30

T-SPINE - AP PROJECTION CENTRING POINT

Answer 30

Central ray vertical to the image receptor Midline at level 5cm below sternal notch (T7)/ midway between xiphisternum and sternal notch Ensure tube locked/aligned with bucky.

Question 31

T-SPINE – AP PROJECTION Essential Image Characteristics

Answer 31

Bony cortex and trabeculae visualised - kVp C7 – L1 demonstrated Intervertebral disk spaces demonstrated Spinous process should be central within vertebral bodies (no rotation).

Question 32

T-SPINE - LATERAL PATIENT POSITION

Answer 32

Lay patient on table in the lateral position M-S plane parallel and middle of axilla coincident with midline of table or vertical IR Arms raised and folded over head Vertebral column parallel to cassette Shoulders superimposed ASIS superimposed

Question 33

T-SPINE - LATERAL CENTRING POINT

Answer 33

Central ray vertical to the image receptor 3 – 4” below suprasternal notch (T7) Perpendicular to mid-axillary line Expose on arrested inspiration, in practice this is the armpit

Question 34

T-SPINE – LATERAL

Answer 34

Bony cortex and trabeculae seen - kVp Intervertebral disk spaces demonstrated. Intervertebral foramina superimposed Bodies of T3-T12 demonstrated.

Question 35

Thoracic Spine - Considerations

Answer 35

Different range of densities overlying TSP = different attenuations of the XR beam\ Upper TSP superimposed by air filled trachea Lower TSP superimposed by denser heart + liver Thinner AP at top, thicker at bottom Ribs superimpose TSP lateral Difficult to demonstrate whole AP TSP in one projection

Question 36

Thoracic Spine - SOLUTIONS

Answer 36

High KVp – demonstrates TSpine in useful density range Filters to even out densities (not often used these days) Anode heel effect – anode cranially ensures higher intensity of XR beam directed at the larger/denser lower end of the T-Spine Gentle breathing blurs out ribs (not often used due to longer exposure time/increased dose and risk of unsharpness of spine). These are quite dated techniques now. The advanced software removes the need for filters and breathing exposures. Correct positioning technique, use of grids and correct use of AEC are essential!

Question 37

C-Spine injury prevalence

Answer 37

The most common mechanism of injury is accidental falls Followed by motor vehicle/transport injuries. A common site of injury is the atlantoaxial region the most commonly injured levels in the subaxial cervical spine are C6 and C7. 1/3 of injuries identified are considered clinically insignificant. Despite surprising number of clinically minor injuries, 55% of spinal cord injuries occur in the cervical spine region.

Question 38

CERVICAL SPINE specific clinical indications

Answer 38

Trauma Unconscious patient (Unsure of injury if fallen) ? Ankylosing spondylitis ? Bone primary/hot spot ? Osteomyelitis ? RA Pain and radiculopathy

Question 39

C-SPINE – Anteroposterior (AP) PATIENT POSITION

Answer 39

Patient erect/supine with posterior aspect of head and shoulders against IR M-S plane in midline at right angles to the IR Depress/relax the shoulders Elevate patient’s chin so that symphysis menti and occiput are superimposed

Question 40

C-SPINE – Anteroposterior (AP) CENTRING POINT

Answer 40

Centre vertical central ray to sternal notch – then angle central ray Cranially to the thyroid cartilage (5-15º)

Question 41

C-SPINE - AP IMAGE CRITERIA C3 – T1

Answer 41

Bifid spinous process of C3 2. Superimposed articular processes 3. Uncinate processes 4. Air filled trachea 5. Transverse process of C7 6. Transverse process of T1 7. 1st rib 8. Clavicle

Question 42

C- Spine Essential Image Characteristics

Answer 42

The image must demonstrate the third cervical vertebra down to the cervical-thoracic junction. Lateral collimation to soft tissue margins. The chin should be superimposed over the occipital bone

Question 43

C-spine top tips

Answer 43

3rd cervical vertebra obscured by mandible- Mandible not superimposed over occiput - chin not raised enough 3rd cervical vertebra obscured by occiput- Mandible not superimposed over occiput - chin raised too much Top part of C-Spine ‘shooting off’ the top of the image receptor- Remember to align image receptor after angling the x-ray tube

Question 44

C-SPINE - LATERAL Patient position

Answer 44

Patient stands with the affected side against the erect chest stand. Feet slightly apart. M-S plane parallel to the IR Chin slightly raised preventing the angle of the mandible from being superimposed over bodies of the upper cervical vertebrae Ask patient to depress shoulders

Question 45

C-SPINE - LATERAL Centering point

Answer 45

Central ray horizontal to the image receptor (SID = 180) Centre at level of C4 (2.5cm behind, 5cm below angle of mandible)

Question 46

C spine- essential image characteristics

Answer 46

- Entire cervical spine and upper part of T1 should be included (C7-T1 joint space). - Mandible or occipital bone should not obscure any part of the upper vertebra. - Angles of the mandible and the lateral portions of the floor of the posterior cranial fossa should be superimposed. - Soft tissues of the neck should be included.

Question 47

Air-Gap technique:

Answer 47

Gap between C-spine & IR Reduces amount of scatter reaching the IR – improving image quality without need for a grid. Removing need for a grid means exposure factors and therefore dose can be reduced. Increased SID with air-gap can counteract magnification Increased SID can prevent geometric unsharpness.

Question 48

C- spine lateral top tips

Answer 48

Vertebral bodies not superimposed- MSP not parallel Rotation of neck Mandible superimposed over anterior borders of vertebral bodies- Chin not raised enough T1 not demonstrated- Superimposition of shoulders; Inadequate penetration

Question 49

C-SPINE – PEG VIEW (AP C1-C2 PROJECTION) PATIENT POSITION

Answer 49

- Patient erect/supine with posterior aspect of head and shoulders against IR - M-S plane in midline at right angles to the IR - Neck extended so that the inferior border of the upper incisors are superimposed on the occiput (an imaginary line joining the tip of the mastoid and the inferior border of the upper incisors is at right angles to the IR) - Immediately prior to exposure ask patient to open mouth as wide as possible.

Question 50

C-SPINE – PEG VIEW (AP C1-C2 PROJECTION) entering point and collimation

Answer 50

CENTRING POINT Central ray vertical to the image receptor Level of lower border of incisors (through open mouth) COLLIMATION SUP: Upper C1 INF: Body C3 LAT: Transverse process

Question 51

C-SPINE - AP PEG/C1-C2 PROJECTION: image criteria

Answer 51

Upper teeth and occiput superimposed Odontoid peg and articulation demonstrated through open mouth NO ROTATION (can mimic misalignment of lateral masses) Ensure symmetry of lateral masses

Question 52

C-SPINE- ADDITIONAL PROJECTIONS

Answer 52

Anterior/posterior obliques Horizontal Beam Lateral Lateral extension Lateral flexion Lateral C7/T1 (Swimmers View)

Question 53

Anteroposterior oblique

Answer 53

Demonstrate intervertebral foramina for size, shape and any impingement

Question 54

Horizontal beam lateral

Answer 54

Trauma patients – avoid moving the patient and exacerbating their injury

Question 55

Lateral flexion & lateral extension

Answer 55

To assess range of movement for cervical spondylosis To assess stability of spine To assess atlanto-axial joint for RA patients prior to intubation for anaesthetic.

Question 56

‘Swimmers’ Lateral C7 – T1 projection

Answer 56

To demonstrate C7/T1 junction & alignment when unable to do so with a routine lateral

Question 57

Terminology

Answer 57

Spondylo – Spondylitis Spondylosis Spondylolysis Spondylolisthesis Retrolisthesis

Question 58

Spondylitis

Answer 58

Inflammation of the vertebrae Ankylosing Spondylitis: a painful, progressive, rheumatic disease mainly affects the spine can also affect other joints, tendons and ligaments. Bamboo spine

Question 59

Spondylosis

Answer 59

General term for degenerative changes due to OA (Osteoarthritis) Can affect cervical, thoracic and lumbar regions Bony spurs Osteophytes at the anterior, lateral, and less commonly, posterior aspects of the superior and inferior margins of vertebral bodies

Question 60

Spondylolysis

Answer 60

Defect of the pars interarticularis Stress injury common in young athletes

Question 61

Spondylolisthesis

Answer 61

Anterior displacement of vertebra or vertebral column Most common in L4/L5 and L5/S1 Graded 1-4 Retrolisthesis is displacement posteriorly in the opposite direction

Question 62

Spinal variations - Kyphosis

Answer 62

Anterior curvature of the thoracic spine