Imaging lumbar spine - exam 3 Flashcards
Who should get imagining with low back P!
> 50 yrs. of age w/ hx of cancer
saddle parathesis
bowel and bladder dysfunction
specific neurological deficits (spinal m. brain, spinal cord)
progressive/disabbling symptoms
no improvement after 6 wks. of conservative Rx
Imaging does improve outcomes? T or F
False; DOES NOT
Black:
Gray:
White:
Bright white:
Solid white:
Air
Soft tissue
Bone
Dyes
Metal
Viewing -AP and PA projections
—place on the viewer as if the ______________
—exception
–patient were facing you and in an anatomical position
–hands and feet viewed with toes or fingers pointing up
________ view is in the path of the beam
identify at least _____ markers such as _______ and _________
Lateral
2; PHI and side of body
ABCS:
alignment, bone density, cartilage space, soft tissue
misalignment indicated fx/dislocation and possible cord compromise -
alignment
bone density - outer __________ bone brighter white than inner _________ bone
cortical; cancellous
narrowing, sclerosis, growth plates -
cartilage space
Soft tissue:
muscle wasting, capsular distension from swelling
periosteal disruption or rasing
Routine radiographs: (4)
AP
Lateral
Right and Left Oblques
Lateral L5, S1
Normal findings for AP view:
vertically aligned vertebral bodies
preserved intervertebral spaces
midline SPs
—tear drop shaped
—smaller spacing in lower segments
Normal findings for AP view: Articular Processes (2)
—casts a butterfly-shaped shadow on vertebral bodies
—joints not specifically visible but alignment is noted
Normal findings for AP view: Pedicles (2)
oval densities
equidistance from SPs
Normal findings for Lateral view:
_______parallel lines
_______ and ______ border?
vertebral bodies are ________ w/ ______heads
________intervetbral spaces
intervertebral or lateral foramen L5, S1 is the ________
_________observe L5, S1 due to illiac crest
3 parallel lines
ant. vertebral border ; post. vertebral borders
boxed; smooth
perserved
smallest
CAN NOT
Normal findings for lateral view:
Should remain __________ whether the low back is in neutral, flexed, or extended
constant
Normal finding for Lateral L5, S1:
close up of _________junction
normal vertebral alignment by _____ parallel lines
_______disc spaces
lumbosacral
3
well preserved
Normal finding for Lateral L5, S1: WB views
What is Barges Angle -
— _____º average
What is Ferguson’s Angle-
—_____º average
angle between sacral base and vertical line
53º
angle between sacral base and horizontal line
41º
Normal findings for Lateral L5, S1: WB views
Smaller Barges and Larger Fergusons indicates:
more lordosis
greater facets compression, ant. shearing forces and lateral foramen narrowing
Normal findings for Lateral L5, S1: WB views
Larger Barge’s and smaller Fergusons indicates:
less lordosis
greater vertebral body and discal compression
The oblique view is best for picking up: (2)
spondylolysis and spondylolisthesis on radiograph
The normal oblique view you should see what structures
articular processes, facets, pars interarticularis , and pedicles - Scottie Dogs
what are major advantages of CT scan?
less overlap of structures due to slicing
able to locate subtle bone changes
what are major disadvantages of CT scan/
greater radiation exposure
limited with soft tissue abnormalities
how do you start to understand a CT image?
start with scout image
locate specific slice position and image
how do you read transverse plane slices of CT?
patient is supine so anterior surface is at the top of each image slice
looking upward at the anatomic structures from below so your right is patient’s left
how are sagittal plane slices viewed on CT image?
left to right
what are MRIs best at looking at?
Slicing and positioning as with CT
what are major advantages of MRI?
less overlap like CT due to slicing
excellent at soft tissue abnormalities, cancellous bone, staging metastasis
no radiation like with CT and X ray
high resolution
what are major disadvantages of MRI?
contraindications with magnetic implants except for stable joint implants
precaution with claustrophobia
In a T2 image, fluid is ____
bright
In a T1 image, fluid is _____
dark
in a T1 image bright signals are from and dark signals are from:
bright: fat and bone marrow
dark: cortical bone and fluid
what are T1 best for demonstrating?
anatomical definition of structure
in a T2 image bright signals occur from?
fluid and water
what are T2 best for demonstrating?
swelling and neoplasms particularly in cancellous bone
what two structures are often gray in both T1 and T2 images?
nerve
muscle
how does inflammation present on T1 images? T2?
low (dark)
high (white)
