thoracic spine technique Flashcards
clinical indications for t-spine (10 indications)
1) compression #
2) wedge #
3) chance #
4) dislocation
5) scoliosis
6) kyphosis
7) spondylosis
8) ankylosing spondylitis
9) osteoporosis
10) metastatic disease
6 ways radiation protection for t-spine
1) identification check
2) careful technique to avoid repeats
3) gonad protection applied wherever practicable
4) efficient collimation
5) application of the 28 day rule
6) consider using alternative imaging modalities e.g. ultrasound
how does the patient lie on the table
supine with the head resting on the pillow and arms relaxed at the patients side
what is the long axis of the patient in relation to the midline of the table (AP position)
long axis is co-incident with the midline of the patient
what should the ASIS’s be to the table top (AP)
equidistant in order to prevent rotation
what is MSP
median sagittal plane
what is the MSP of the patient to the table top (AP)
MSP is 90 degrees to table top indicating no rotation
how should the patients head be (AP) and why
the head should be raised to ensure the chin is clear of the upper thoracic area
where and what ray should be used for an AP t-spine
should direct the vertical ray 90 degrees midway between the sternal notch (T1) and the xiphi-sternum (T12) in the midline
what anatomical point is associated with T1
the sternal notch
what anatomical point is associated with T12
the xiphi-sternum
what should be ensured of the patient to the imaging receptor
alignment
how should an AP t-spine be done; on what breathing and SID
expose on arrested respiration using an SID of 100cm
what is the correct area of interest for an AP t-spine (3 points)
1) C7 superiorly
2) Just below L1 inferiorly
3) Costo-vertebral joints and medial 1/3 of ribs, laterally
what is the correct positioning for an AP t-spine (5 points)
1) vertebral bodies to be co-incident with midline of imaging receptor
2) spinous processes central to vertebral bodies
3) evidence of intervertebral joint space
4) sternal ends of clavicle equidistant from spine indicating no rotation
5) mandible clear of upper thoracic cavity
what are the other 8 image criteria (other than AOI and positioning)
1) correct name
2) correct aspect marker
3) no artefacts
4) evidence of collimation
5) need for repeats
6) further views
7) correct exposure factors
8) evidence of pathology
what should the cortical outlines and trabecular patterns be
1) cortical outlines of the vertebrae should be intact
2) trabecular pattern should be comparable between each of the vertebrae
what happens to the size of the vertebral bodies
increases progressively from T1 to T12
what should the interspinous distance be
approximately equal throughout the throracic spine indicating no widening or loss of joint space
what should the spinous process be (AP t-spine)
centralised throughout the t-spine indicating no disruption of the vertebral alignment
what should the inter-pedicular distance be
virtually equal throughout the t-spine indicating no disruption of the vertebral bodies
pedicles and transverse processes should be
symmetrical throughout the t-spine indicating no disruption of the vertebral alignment
there should be no evidence of…
abnormal soft tissue outlines
what to abnormal soft tissue outlines indicate
para-vertebral swelling
why do we use expiration for a t-spine (2 points)
1) as there is less contrast as the lungs are not fully filled with air
2) expiration is seen as the phase where the body is at rest and organs in the ‘true’ anatomical position
how should the patient lie for a lateral t-spine
patient rolls onto affected side (posterior aspect of patient facing radiographer)
elbows flexed and patients arms resting anteriorly
how are the patients hips and shoulders adjusted and why
so that they are in the same plane, allowing MSP to be parallel to the table top
the long axis of the patient is what with the image receptor (lateral)
co-incident with the midline of the IR
how should knees and ankles be and why
flexed to aid stability
where and what ray should be used for a lateral t-spine
a direct vertical central ray 90 degrees to 2.5cm behind the mid-axillary line at the level of the inferior angle of the scapula (the postero-inferior aspect of the axilla)
what SID is used for lateral t-spine
100cm
where is a lead rubber sheet placed and why
posterior to thoracic region to improve image quality by absorbing scattered radiation
on what respiration should a lateral t-spine be taken
arrested respiration
why is a longer exposure time used for a lateral t-spine
patient breathes throughout the exposure to blur out the overlying ribs and visualise the vertebrae more clearly
what is the correct area of interest for a lateral t-spine (4 marks)
1) C7 superiorly
2) L1 inferiorly
3) Soft tissue borders posteriorly
4) Soft tissues anteriorly following the vertebral line
Correct positioning for lateral t-spine (4 marks)
1) Vertebral bodies to co-incident with midline of image receptor
2) Superimposition of anterior, posterior, superior and inferior borders of vertebral bodies
3) Evidence of intervertebral joint space
4) Intervertebral foramina open and superimposed
what should there be for posterior ribs (lateral)
symmetry and alignment
