EVERYTHING Flashcards
T/F:
X ray Uses a single pulse of ionizing radiation
True
XRAY
Good for:
Bad for:
Good for: bones and airspaces
Bad for: soft tissue and overlapping structures
Five basic radiographic densities
(a) Air (Darkest)
(b) Fat (Less Dark)
(c) Fluid/Blood/Soft Tissue (Gray)
(d) Bone (White)
(e) Metal/Contrast (Most White)
XRAY
When would you use an AP chest
Used if patient is unable to stand or sit for a PA view
T/F:
CT
Uses multiple pulses (“shots”) of ionizing radiation
True
CT
What are the three views
(a) Sagittal or Median
(b) Coronal
(c) Axial or Transverse or Cross-sectional
MRI
Does MRI use ionizing radiation
No exposure to ionizing radiation, but time consuming
MRI
Good for:
Bad for:
Good for: Soft tissue (nerves, muscles, connective tissue, brain, joints).
Bad for: People who cannot hold still or have ferrous metal in the body.
MRI
What are the three views
(a) Sagittal or Median
(b) Coronal
(c) Axial or Transverse or Cross-sectional
Same as CT
US
Does US use ionizing radiation
No radiation, but can’t go very deep
US
Good for:
Bad for:
Good for: Determining fluid vs solids, abdominopelvic imaging (gallbladder, kidneys,
uterus, testis), assessing blood flow (Doppler).
Bad for: Things under bones (chest) and air filled chambers, deep things
US
What are the two views
Longitudinal (same as sagittal)
Transverse (same as axial)
What are the 6 things that you must confirm during the pre-read
(a) Image is from the correct patient
(b) Image is from the correct date
(c) Image is the correct body part
(d) Image is the correct type
(e) Image has the number of views expected
(f) Check to see if any comparison films exist
How do you assess technical adequacy
- Rotation
a. Look at the clavicles relative to the vertebral column - Inspiration
b. Should be able to count 9-10 ribs - Penetration
(a) Should see the ribs through the heart
(b) Should barely see the spine through
the heart
(c) Should see pulmonary vessel near the edges of the lungs (lungs should not be completely black).
1) Over-penetrated film
a) Lung fields almost completely black
b) Suggests pneumothorax
2) Under-penetrated film
a) Soft tissue structures are obscured
b) Image appears bright suggesting consolidation (like a pneumonia).
What are the ABCDE’s of reading a CXR
(a) A- Airways/Airspaces
(b) B- Bones/Soft Tissue
(c) C- Cardiac Shadow
(d) D- Diaphragm
(e) E- Everything else
How do you measure the cardiac silhouette
(a) The transverse diameter of the silhouette should NOT exceed 50% of the transverse diameter of the thoracic cage, called cardiothoracic ratio (only applies to PA film).
1) AP films magnify the heart
2) Shallow inspiration makes the heart horizontal and larger
(b) Cardiac borders (moguls):
1) Upper right border: Superior vena cava
2) Lower right border: Right atrium
3) Left border (from the top):
a) Aortic arch
b) Pulmonary arteries
c) Left atrial appendage
d) Left ventricle
What are the OTTAWA rules for ankles
(a) Has pain in the “malleolar” zone AND
(b) Has bone tenderness at the posterior edge (6cm) of the lateral or medial malleolus
OR
(c) Inability to bear weight both immediately after the injury and for four steps in the
evaluation room.
1) If the patient can transfer weight twice to each foot, the patient can bear weight.
2) If the patient limps, the patient can bear weight.
What are the OTTAWA rules for acute foot pain
(1) Ottawa Rules
(2) Foot series is indicated if:
(a) Has pain in the “midfoot” region AND
(b) Has bone tenderness at the base of the 5th metatarsal or the navicular OR
(c) Inability to bear weight both immediately after the injury and for four steps in the evaluation room.
1) If the patient can transfer weight twice to each foot, the patient can bear weigh.
2) If the patient limps, the patient can bear weight.
What are the OTTAWA rules for knee pain
(a) Age >55 year old*
(b) Isolated tenderness of the patella (with no other bony tenderness to the knee).*
(c) Tenderness at the head of the fibula.
(d) Inability to flex the knee to 90 degrees.*
(e) Inability to bear weight both immediately after the injury and for four steps in the evaluation room (limping is allowed).*
(f) Ottawa knee rules are for bony injuries.
(g) If you suspect ligamentous injury, MRI is the preferred imaging.*
(h) Immobilize while awaiting further evaluation.
(i) If plain radiographs are negative and you still suspect bony fracture, consider CT.
When would you consider imaging for headaches
(1) Consider imaging if:
(a) Associated with head/neck trauma
(b) New, worse or new features, or abrupt onset headache
(c) Focal neurologic signs or symptoms
(d) Thunderclap headache (sudden, severe)
(e) Headache radiating to the neck
(f) Persistent positional headache
(g) Temporal headache in older than 55 years of age
(h) Suspect infection
1) Associated with cough, exertion, or sexual activity
(2) CT is preferred for trauma, to rule out hemorrhage, bone abnormalities, or prior to lumbar punctures.
(3) MRI is preferred for soft tissue causes such as tumors, or vascular.
What are common fractures seen on orthopedic xrays
(1) Oblique- has angulated fracture line*
(2) Transverse- runs perpendicular to the shaft of the bone
(3) Spiral- has a multiplanar and complex fracture line*
(4) Overriding-one bone is displaced over the other
(5) Distraction - fragments are separated by a gap
(6) Torus - looks like a bump classified as incomplete fracture seen in children*
(7) Greenstick - fractures by bending like a green twig classified as incomplete fracture seen in children.*
(8) Comminuted - have more than two fracture fragments
In general, imaging should confirm a ____
(a) It should not be a ______
In general, imaging should confirm a suspicion.
(a) It should not be a “fishing expedition”
For suspicion of stress fractures, what are the three things to keep in mind
(1) X-rays may be normal initially
(2) Bone scan can show abnormalities before X-ray findings
(3) Consider CT or MRI
3 reasons for getting shoulder imaging
(1) Traumatic cause
(2) Presence of pain
(3) Loss of range of motion
