Radiology Clinical IV

~~~Spine & Bony

Thorax~~~~~

Image Review

The following information is only a personal suggested guideline to follow when positioning for Spine and

Bony Thorax exams.

For additional information on positioning of these

exams, please reference your Radiographic

Positioning and Related Anatomy Textbook.

Cervical

Spine*Good

positioning Images will

always be on the right.

Lateral C-Spine• CR ┴ to IR• Relax/drop shoulders• Body in lateral position • Protract chin (to get mandibular

rami away from the anterior arch of C-1)• Direct CR to C4• Expiration

Artifact and poor centering and technique

Artifact and C7 is not visualized.

Motion & no marker

Image ok, just showing pathology of previous surgery.

Poor centering and technique, due to patient moving and causing AEC chambers to not hit appropriate anatomy. Optional: Choose manual technique.

A

B

F

E

D

C

T-1

T-1

Superior

Articular

Process

Inferior Articular

Process

Zygapophyseal joint

Spinous Processor C7Vertebral Prominens

Intervertebral Disc Space

Body

AP C-Spine• CR is 15°-20° cephalad• Body in AP position• Ensure tip of mandible to

base of skull is ║ with CR<• Direct CR to C4

Artifact and poor positioning of headAnd no marker

Image ok, just showing pathology of previous surgery.

4

5

6

7

2

3

4

5

6

7

Red line = chin, pink line = base of skull.Head is flexed downward, causing chin to superimpose on top of upper C-spine.

4

5

6

7 CR

Red line = chin, pink line = base of skull.Head is flexed downward, causing chin to superimpose on top of upper C-spine.

3

4

5

6

7

2

3

4

5

6

7

Red line = chin, pink line = base of skull.Head is extended to far back, causing base of skull to superimpose on top of upper C-spine.

3

4

5

6

7

2

3

4

5

6

7

CR

Red line = chin, pink line = base of skull. Left Image shows the head over extended, causing the base of skull to superimpose on top of upper C-spine. Right image shows how this positioning error took place viewing the patient from the side.

CR

Left Image is an excellent AP Cervical Spine ~ Right Image is an example of how you should step to the side, and view the patient’s lateral side to ensure that the “lower mandible to base of skull” line is parallel with the CR.

Oblique C-Spine• CR 15°cephalad for AP

or 15° caudad for PA• Body is rotated 45°• Protract chin• Direct CR to C4

Positioning- over rotatedCR – not centered and no angleExposure – due to being not centered

Repeatable error?

Anatomy - patient’s mandible is in the way of the c-spine. No marker

Repeatable error?

Positioning – under rotated & Patient’s mandible is in the way of the c-spine.

Repeatable error?

LPO will show right intervertebral foramina (the ones closer to the CR)

Extremely poor positioning ~ possible due to patient’s inability to cooperate.

Patient’s mandible is in the way of the c-spine.

Patient’s mandible is in the way of the c-spine.

A

B

C

DE

Hyoid Bone

Intervertebral Foramen

Pedicle

InferiorVertebralNotch

SuperiorVertebralNotch

Odontoid C-Spine• CR is ┴ to IR• Body in AP position• Open mouth to ensure upper

incisors are ║ with base of skull

• Ensure no rotation of skull• Direct CR into open mouth

Positioning - Head is over extended and slightly tilted to the left. Poor collimation

Repeatable error?

Positioning - Head is over extended too far back .

Repeatable error?

Positioning - Head is flexed too far forward. No Markers

Repeatable error?

Poor positioning:A) Upper teeth B) Motion of lower teeth C) Base of skull D) Motion of moving mandible

AB

C

D

Even almost perfect positioning leads to no visualization of the odontoid. In this case, if the exam was for trauma, you would have to do an additional Judd or Fuchs position.

Besides excellent positioning, the mouth is also opened appropriately. To show any displacement of C1 & C2 laterally. Sometimes fillings or crowns of the back molars prohibit this visualization.

Pathology - Ankylosing Spondylitis = Calcification with ossification (formation of bony ridges between vertebrae), creating stiffness and lack of joint mobility.

ThoracicSpine

AP T-Spine• CR ┴ to IR• Body in AP position• Flex legs• Direct CR to T7• Expiration• Opt. If using a long exposure

technique-Suspending respiration on inspiration is recommended.

Repeatable error? Incorrect CR centering - Clipped anatomy

Repeatable error? Incorrect CR centering - Clipped anatomy

Poor image, possibly due to using AEC. Manually set, long exposure techniques help blur out mediastinal structures to better visualize costovertebral joints. Note: Right adrenal gland calcification.

Poor image, possibly due to using AEC. Patient is obviously barrel chested causing lower T-spines to be too light. Manually set, long exposure techniques help blur out mediastinal structures to better visualize costovertebral joints.

Pathology - Scoliosis

Lateral T-Spine• CR ┴ to IR• Body in Lateral position• Flex legs• Ensure NO rotation• Direct CR to T7• Expiration• Opt. If using a long exposure technique-

Suspending respiration on inspiration is recommended.

Pathology – showing previous surgery.

Poor image, possibly due to using AEC. Manually set, long exposure techniques help blur out lung markings to better visualize the spine.

Better Technique BEST Technique!

Swimmers – suggestion:Look for the wishbone.

The clavicles create the wishbone ends. Then between them will be the

first rib as it attaches to T-1. C-7 is located just above this spine.

Swimmers• CR ┴ to IR(*3°-5° caudad<)• Body in Lateral position• Separate shoulders• Direct CR to T1• Expiration• Opt. Long exposure technique

Oblique T-Spine• CR ┴ to IR• Rotate whole body 20° from true

lateral to create a 70° from plane of table.

• Direct CR to T7• Expiration• Opt. If using a long exposure technique-

Suspending respiration on inspiration is recommended.

A C

Oblique T-SpineRotate body 20° from true lateral, to create a 70° oblique from plane of table.

B

Oblique T-Spine• Anterior obliques will visualize the

zygapophyseal joints closest to the IR.• Posterior obliques will visualize

zygapophyseal joints closest to the CR.

Superior Articular Process

Inferior Articular Process

Zygapophyseal joint

A

B

DG

HC

EF

Body

Vertebral Foramen

Transverse Process

Costotransverse Joint

Costovertebral Joint

Pedicle

LaminaSpinous Process

Lumbar Spine

AP L-Spine• CR ┴ to IR• Flex legs• Ensure NO rotation of pelvis• Direct CR to iliac crest• Expiration

Repeatable error?Incorrect CR/IR alignment –

Clipped anatomy

Repeatable error? Marker in anatomy

Repeatable error? Marker in anatomy

Pathology – Gun shot.

Pathology – Previous surgery. Kyphoplasty

Pathology – showing previous surgery.

Pathology – showing Scoliosis.

Lateral L-Spine• CR ┴ to IR• Flex legs• Ensure NO rotation• Ensure NO “sag”• Direct CR to iliac crest• Suspend/Expiration

Repeatable error?Structures are not shown – positioning

and no marker

Double exposure, and clipped spinous processes.

Pathology – showing previous surgery(almost clipped L1 with centering).

Pathology – showing previous surgery-Kyphoplasty

Pathology – Impacted compression fracture/MRI

Poor marker placement.

A

BC

D

E

F

Intervertebral Disc Space

BodyIntervertebral

Foramina

Pedicle

Inferior Vertebral Notch

Superior Vertebral Notch

Oblique L-Spine• CR ┴ to IR• Rotate whole body 45°& align

spine with IR• Direct CR to 1” above iliac

crest & 2” medial to up side ASIS

• Suspend/Expiration

C

E

F

A

G

D

B

Nose

Ear

Body

Foot

Zygapophyseal Joint

Eye

Neck

The Scotty Dog

Transverse Process

Superior Articular Process

Lamina

Inferior Articular Process

Zygapophyseal Joint

Pedicle

Pars Interarticilaris

L5-S1 L-Spine• CR ┴ to IR• Flex legs• Ensure NO rotation• Ensure NO “sag”• Direct CR 1.5” inferior to iliac

crest & 2” posterior to ASIS• Suspend/Expiration

Repeatable error?

Incorrect CR/IR alignment – Clipped anatomy

Repeatable error?Incorrect Centering–

Clipped anatomy

Left Image shows the “cake top” or “pop can” effect of the vertebral bodies when no radiolucent support is used under the waist.

Left Image shows white ovals of the “cake top”or “pop can” effect of the vertebral bodies when no radiolucent support is used under the waist.

Left Image shows that no radiolucent support was used under the wait and possibly no caudad angle of the CR was used, causing the L5-S1 space to not be open. The yellow dotted lines show how the iliac crests are not superimposed.

Flexion & Extension L-Spine

Flexion – both are good images

Extension– both are good images

Sacrum

&

Coccyx

AP Sacrum• CR is 15° cephalad (to the nose)

• Body in AP position• Flex legs• Direct CR 2” superior to the

pubic symphysis

Left Image shows that the patient needs to empty their bladder before the x-ray is taken.

Left Image shows not enough cephalad angle. See how sacral foramina are still slightly foreshortened as compared to the image on the right.

AP Coccyx• CR is 10° cephalad (to the toes)• Body in AP position• Flex legs• Direct CR 2” superior to the

pubic symphysis

Left Image shows that the patient needs to empty their bladder before the x-ray is taken.

Artifact - patient needs to remove their underwear before the x-ray is taken.

Repeatable Error?

Lateral Sacrum/Coccyx• CR ┴ to IR• Flex legs• Ensure NO rotation• Ensure NO “sag”• Direct CR 3”-4” posterior to

ASIS

Does not appear as though support was used under the waist to help make the spine parallel with the IR. Image is also very gray from poor technique choice.

Image appears as though the body is rotated.

Image is better but still appears as though support has not been used under the waist to help make the spine parallel with the IR. Could have centered slightly more posterior as distal sacrum and coccyx are almost clipped.

Sacroiliac Joints

Axial S-I Jts• CR is 30°-35° cephalad• Body in AP position• Flex legs slightly• Direct CR 2” inferior to the

ASIS

Oblique S-I Jts• CR is ┴ to the IR• Body in AP position, then

rotated 20°-25° each way• Direct CR 1” medial to

upside ASIS

BonyThora

x

Rib Techniques“Long” exposure is best for fine detail of ribs.(Low Ma & 2-3 sec)

• Pt holds their breath in for upper ribs and out for lower ribs

• Expose on suspended respiration

Oblique RibsHow to remember which oblique to do in order to get the elongated view of the ribs:• Turn the spine away from

the effected side• AP towards IR and• PA “Away” from IR

Image on the left - Uses AEC and is not ideal for rib x-rays. Image on the right - Uses a manually set long exposure technique which best visualizes rib detail.

Image on the left – poor detail due to inappropriate KvP, poor histogram settings for processing image or due to using AEC.

Image on the left – slightly better technique, AEC was probably still used but at a low KvP range to enforce a longer exposure.

Image on the left - Uses AEC and is not ideal for rib x-rays. Image on the right - Uses a manually set long exposure technique which blurs out heart and lungs to best visualizes rib detail.

Image on the left – Manually set technique using long exposure, but the patient’s breast needs to be moved out of the way. Ask patient to hold their breast out of the way.

Sternum Techniques“Breathing” Technique is best for viewing the sternum in the RAO position. Low MA and 2-3 second exposure.• Pt exhales slowly to blur

out lung markings and ribs.

RAO Sternum• CR is ┴ to the IR• 40” SID• Body in 15°-20° RAO

(Deep chested thorax requires less rotation than thin-chested)

• Direct CR to mid-sternum and 1” to left of midline

• Breathing Technique

Lateral Sternum• CR is ┴ to the IR• 72” SID• Body in true lateral position• Arms back• Direct CR to mid-sternum • Expiration

S/C Jts• CR is ┴ to the IR• 40” SID• Direct CR T2/T3 (3”

inferior to vertebral prominens)

• Expiration

Both Oblique SC Jts• CR is ┴ to the IR• 40” SID• Rotate body 10°-15° each way for

RAO and LAO• Direct CR (T-3) 3” inferior to

vertebral prominens & 1”-2” to upside from midline

• Expiration

With lesser body rotation (5°-10°) the upside S/C joint will be visualized.

~The End~