quiz 1 Flashcards
what does PACS stand for?
picture archiving communications storage
what types of images can be stored through PACS?
- xray
- CT
- MRI
- US
- fluoroscopy
- nuclear medicine
advantages to x-rays
- inexpensive
- commonly used
- can be obtained almost anywhere via portable devices
disadvantages to x-rays
- uses ionizing radiation
- limited to 5 basic densities
5 basic densities
- air
- fat
- soft tissue/fluid
- calcium
- metal
air on an x-ray
- absorbs least amount of x-rays
- appears blackest
fat on an x-ray
- gray
- slightly darker than soft tissue
soft tissue/fluid on an x-ray
- both have same density on films
- cannot tell the difference between the two
calcium
- most dense of naturally occurring materials
- absorbs the most x-ray
metal
absorbs all x-rays and appears whitest
requirements for production of x-rays
- source of electrons
- way to accelerate them
- way to stop them
- vacuum
x-rays are the initial imaging study of choice for what type of injury?
skeletal trauma
lateral x-ray position
- 90 degrees to AP or PA
- decubitus is recumbent to horizontal beam
lateral decubitus x-ray position
- used to see air/fluid levels
- side up shows air
- side down shows fluild
- good for abdominal problems
oblique x-ray view
- halfway between AP/PA and lateral view
- most extremity projections involve 3 views
x-ray projections
- path of central ray as it exits and goes through patient to image receptor
- AP/PA
- axial
- tangential
- lateral
- oblique
extremity pain with negative x-ray
- treat with splint
- f/u with ortho in 7-10 days
- repeat x-rays may show cortical changes
underpenetrated film
appears too white, no goo range of densities and have blurring of interfaces
overpenetrated film
appears too black, no good range of radiological densities and absence of interfaces
what is the most important part of musculoskeletal evals?
history
reading the x-ray
- viewed in anatomical position
- your left is pts right
- extremity work viewed fingers/toes up
- assess adequacy of image
- motion, magnification, distortion
- geometric vs photographic properties
geometric properties
- magnification- size
- distortion
- elongation- shape
- foreshortening- shape
shape distortion
- elongation occurs when tube or image receptor are improperly aligned
foreshortening
the further away from the plate an object is the bigger it looks
ABCS of reading the x-ray
- A- adequacy, alignment
- B- bones
- C- cartilage
- S- soft tissue
CT scan
- uses rapidly spinning arrays of x-rays and computer processing to increase sensitivity of findings visible
- cross-sectional imaging
- mod expensive
- uses much higher dose of ionizing radiation than x-ray
CT better than x-ray in:
- ident subtle fractures
- visualizing articular fx extension
- assessing presence of articular stop off/gap
ultrasound
- produces images using acoustic properties of tissues
- no ionizing radiation
- useful in eval of soft tissue and blood flow
- less expensive
- portable
MRI
- produces images based on energy derived from H atoms
- atoms placed in magnetic field and subjected to RF pulsing
benefits of MRI
- no ionizing radiation
- good for neuro and soft tissue
- helpful to dx occult fx
fluoroscopy
- utilizes ionizing radiation to produce real-time visual of body
- eval of motion, positioning, GI studies
- eval of fx for reduction and placement of pins/ hardware
- c arm support system
nuclear medicine
- utilizes radioisotopes that have been given property target
- pt is source of radiation
- used for metastases, occult/stress fx, insufficiency fx
5 radiographic opacities
- air
- fat
- soft tissue
- bone
- metal
CXR basics
- AP or PA view
- upright/ erect or supine
- rotation
- inspiration
- penetration
- all landmarks present
how to tell of CXR is rotated
should normally have equal distance between medial end of clavicle and midline of body
why inspiration is important for CXR
- when you inspire diaphragm goes down
- allows for better view of cavity
- should be able to see 10 ribs
CXR penetration
- appropriate- should barely see discs through heart
- over- clearly see discs
- under- don’t see discs at all
pitfalls to CXR interpretation
- poor inspiration -> squish effect
- over or under penetration
- rotation -> shadow summation effect
normal CXR cardiac structure
- central in younger infants and kids
- more on L in older infants and teens/adults
normal CXR cardiac size
- measure R boarder of heart to midline
- measure L boarder of heart to midline
- these two spaces should be less than the wides space at bottom of lungs
- greater than 50% of chest is abnormal
normal CXR diaphragm
- rounded with sharp pointed costophrenic and costocardiac angles
- right diaphragm is usually slightly higher
lung inflitrate
- collection of fluid within lung parenchyma itself
lung effusion
- collection of fluid in a potential space of the lung
- outside the tissue itself
lobes of the R lung
- upper, middle and lower lobes
- upper- more anterior
- middle- anterior and inferior
- lower- posterior
lobes of left lung
- upper- anterior
- lower- posterior
- lingula- bottom part of L lobe
radiopacity
- whiteness
- increased density
radiolucency
- blackness
- decreased density
mass
- solid
- generally well marginated
- doesn’t belong
lesion
- poorly marginated
- doesnt belong
alveolar pattern
- fluffy, soft, poorly demarcated opacifications
possible causes of alveolar pattern
- pulmonary edema
- viral pneumonia
- pneumocystis
- alveolar cell carcinoma
interstitial pattern
- consolidation of interstitial tissue
- looks like branching lines radiating towards periphery of lungs
possible causes of interstitial pattern
- interstitial pneumonitis
- pulmonar fibrosis
vascular pattern
- increase in size of arteries that extend into lung- pulmonary HTN
- decreased size truncation, obliteration of pulm artery- embolus
- lack of vascular marking in the periphery- pneumothorax
atelectasis
- loss of air
- obstructive atelectasis- no ventilation
- compensatory hyperinflation of normal lungs
CHF CXR
- large hila with indistinct markings
- fluid in interlobar fissues
- pleural effusions
- alveolar edema (bat’s wings)
- kerley b lines (interstitial edema)
- cardiomegaly
- dilated prominent upper lobe vessels
boundaries of abdomen
- superior = diaphragm
- posterior = deep back muscles
- lateral= abdominal muscles
- inferior = pelvic floor
9 quadrants of abdomen
- R and L hypochondriac
- epigastric
- R and L lumbar
- umbilical
- R and L iliac
- hypograstric
4 quadrants of abdomen
- R and L upper
- R and L lower
- more commonly used for physical exam
pancreas
- sits across 3 upper quadrants
- also sits in extraperitoneal space
- pancreatic duct joins common bile duct
intraperitoneal anatomy
- pancreatic tail
- stomach
- jejununum, ileum, cecum
- transverse colon
- sigmoid colon
- liver, GB, spleen
retroperitoneal anatomy
- head/neck/body of pancreas
- 2, 3, 4 part of duodenum
- ascending and descending colon
- rectum
- Kidney, ureters
- abdominal aorta
- IVC
adequate abdominal x-ray
- aka KUB xray
- includes diaphragm to top of symphysis pubis
- see spinal owel
- see SI joints
what does string of pearls sign represent
- mechanical bowel obstruction
- can indicate multiple air fluid levels
coffee bean sign
- sign of volvulus
- volvulus= twisting of loop of bowel
- appears as big loop of colon with central dividing line
- can be caused by colon cancer or adhesions from surgery
wilms tumor
tumor of kidney
what disease is associated with string sign
Chron’s
cortical bone
- hard outer surface, compact bone
- provides skeletal support
- site of attachments for tendons and ligaments
- disruption= fracture
cancellous bone
- spongy/ trabecular bone
- found in ends of long bone, pelvis, ribs, skull, vertebrae
- disruption= bone bruise
- has red and yellow marrow
osteoblasts
build bone
osteoclasts
break down bone
metaphysis
- transition of diaphysis and epiphysis
- where growth plates are found
diaphysis
shaft of bone
epiphysis
end of bone
tendon
muscle to bone
ligament
bone to bone
xrays used to evaluate
- cortical integrity
- articular surface congruity
- joint space
- osseous lesions
- bone density (to lesser extent)
what is the most important part of musculoskel exam?
history
comminuted fracture
greater than 2 fracture fragments
fracture types
- transverse
- linear
- nondisplaced
- displaced
- spiral
- greenstick
- comminuted
spiral fracture
- spirals around the bone
- very unstable
- needs surgery
butterfly fracture
- subtype of comminuted
- wedge shaped fracture fragment along shaft of bone
green stick
- fracture does not go all the way through the bone
- fx in convex cortex
- usually in kids
lucent fracture line
- most fx appear this way
- in nondisplaced fx lucent line is thin
- visualization depends on angle of xray
mach bands
- appear at sites of cortex overlap between two bones
- can also be due to skin folds
- most common site- ankle
sclerotic fx line
- compression fx may appear this way
- most common in vertebral bodies and distal radius
cortical buckling
- buckling in absence of fracture line
- often in distal radius
aspects of displacement
- translation
- angulation
- rotation
translation
- line drawn down center of bone with fx
- want to describe translation of distal fx compared to proximal
- describe amount of translation as %
displacement
- loss of normal anatomical position
- direction of displacement described using 2 views
- described in terms of position of distal fragment compared to proximal
angulation
- line drawn down center of bone angled at the fracture
- describe angulation of distal fracture compared to proximal
- amount of angulation in degrees
- need two views
distraction
- common with transverse fx from tension force
avulsion
- caused by abnormal tensile stress on ligaments or tendons
- typical in hand, feet, and pelvis
transverse fx
- perpendicular to long axis of bone
- commonly caused by direct force
- can also be due to tension force
- most common in forearm and leg
oblique fx
- commonly cause by indirect force
- unstable
- usually requires surgery
buckle fx
- aka torus fx
- incomplete fx
- typically occurs after FOOSH
- very stable
salter harris system
- evaluates epiphyseal plate fractures
- common in kids
- salter harris fx can result in premature closure of growth plate
salter harris type 1
- fx plane passes all the way through growth plate
- not involving bone
- good prognosis
salter harris type 2
- fx passes across most of growth plate and up through metaphysis
- good prognosis
- most common
salter harris type 3
- fx through growth plate and epitphysis and into joint
- poorer prognosis
salter harris type 4
- contiguous through metaphysis, physis, and epiphysis
- poor prognosis
salter harris type 5
- crush injury to physis
- crushing does not displace growth plate but damages by direct compression
- worst prognosis
