Lab Practical Written Portion Flashcards
x ray
electromagnetic radiation
less dense (soft tissue) appears dark
bony tissue appears white
can see fractures, foreign objects, degenerative disk disease, malalignment, facet joint dysfunction
lungs-dark
fat-gray
bone-white
can use dye, but often reserved for MRI and CT
x ray purposes
rule out fractures, dislocation, bony abnormalities, foreign objects, tumors, infection (not the easiest to see)
x ray considerations
inexpensive, accessible, quick, generally comfortable
ABCs of x rays
Assess general skeletal structures
- gross size and appearance
- presence of accessory bones
- congenital anomalies
- absence of bones
- deformity
Assess general contour
- irregular in cortical outlines
- presence of osteophytes
- break in continuity of cortex
- angles in cortex
- muscles, tendon, ligament attachment
- previous surgical sites
general Bone density
- adequate contrast between bone and surrounding tissues
- adequate contrast within bone including distinct cortex
- bone density influenced by age, activity level, disorders
- texture abnormalities
Cartilage space
-well-preserved joint space indicates that cartilage is normal thickness
- joint space identified as “potential space” or “radiographic joint space”
- specific to the joint and best measured in WB
- epiphyseal plate:
–> in growing child are cartilaginous
–> evaluated for size comparing skeletal maturity to age
–> borders bound by smooth margin with band of sclerosis
–> may need contralateral films for comparison
radionuclide bone scan
nuclear imaging
short-lived radionuclide to assess abnormalities in bone tissue
shows stress fractures
tracer injected: emits gamma radiation
circulates through body (30 m-2 hrs)
special camera reveals “hot spots” on bone (areas of increased metabolic activity)
bone scan indications
rule out stress fracture, bone infections, tumors, arthritis(not the best)
fluoroscopy
ionizing radiation
allows for “real time image” (used during clinical procedures)
indications/uses similar to x rays
clarity depends on power and type of machine
positron emission tomography (PET)
used to examine cell metabolism and biochemistry of tissues and organs
radionuclide injection: goes to area of abnormal cellular metabolism
3D image of tissues
identify cancers (tumors), thyroid conditions, infections, and bleeding (often done in a series)
TUMORS
magnetic resonance imaging (MRI/MR)
applies a magnetic field to the body (body atoms align along magnetic field, releasing radio wave)
- computer analyses wave to create image
MRI indications
to image organs, soft tissues, bone, tumors, bleeding, inflammation, infection
confirmation of stroke, assessment of intracranial tumor, chronic headache, seizure disorder, demyelinating disorder (MS need GAD)
used extensively in Ortho and neuro
MRI considerations
excessive movement can cause blurry images - sedation may be necessary
claustraphobia - open vs closed machines; again sedation may be necessary
no radiation
can’t have metal
high cost (compared to radiographs)
MRI t1 weighted image
fluid: slow signal intensity (black)
muscle: intermediate signal intensity (gray)
fat: high signal intensity (white)
CNS/brain:
- gray matter: gray
- white matter: white-ish
MRI t2 weighted images
fluid: high signal intensity (white)
muscle: intermediate signal intensity (gray)
fat: high signal intensity (white)
CNS/brain:
- gray matter: gray
- white matter: dark-ish
MR arthrogram
MR with gadolinium
adds dye to the structure
good for identification of cartilage lesions, neurotrauma (demyelination)
gadolinium goes to areas of demyelination - good for tracking MS progression
ultrasound
uses nonthermal sound wave to image soft tissue structures
clarity depends on machine and level of skill of the technician
ultrasound indications
image musculoskeletal structures
used to guide clinical procedures
doppler ultrasound
ID blood flow/obstruction of blood flow
thromboembolism will usually travel, so it’s important to find
computed tomography (CT) scan
ionizing radiation (larger dose than with x ray)
used to scan multiple systems (Ortho, ortho-spine, internal medicine, neurology, etc)
can get back 3D view (very helpful for diagnosis of certain fractures)
an x-ray likely wouldn’t show a fine fracture, but a CT would
non contrast CT indications
stroke, trauma, headache, tumors, seizures, change in mental status, etc.
most common
contrast CT indications
less common
performed when brain tumors or abscesses are suspected and patient can’t get MRI
IV contrast is also given to assess vasculature
CT scan of the brain/skull/SC
findings discussed in terms of densities
white (hyperdense):
- bone, calcium deposits, fresh blood, melanin, contrast
grey (isodense):
- brain parenchyma, glial tumors, subacute fat
dark grey (hypodense):
- CSF, brain edema, fat, chronic blood
black (hypodense):
- air
MRI of the brain
multiplanar assessment
did sequences allow for assessment of dif pathology
no ionizing radiation (good for children)
MRI limitations
much longer study (20-40 minutes)
less available
issues with claustrophobic patients
contraindicated for patients with metallic fragments or implants
FLAIR
similar to T2 but fluid is suppressed and therefore dark
useful for assessing edema/inflammation
imaging of the SC
cervical, thoracic, lumbar
x ray, MRI, CT
MRI of the SC
indications:
- neurological S/S: disc herniation and cervical stenosis
- soft tissue injury evaluation: ligament injury, tumors, or infections
STIR
suppresses fat
edema is bright
