Special studies Flashcards
(37 cards)
What are the four phases of bone scans?
Phase 1: Immediate/flow phase also known as an angiogram. 2-3 seconds.
Phase 2: Blood pool phase. 2-3 minutes
Phase 3: Delayed phase 2-3 hours.
Phase 4: Fourth phase 24 hours.
What do each of the phases of a bone scan test for?
Phase 1: Blood flow
Phase 2: Soft tissue infection
Phase 3: Bone activity
Phase 4: Bone uptake when Peripheral vascular disease is present.
What are the structures that commonly light up in a bone scan?
Bladder Ribs/Sternum Epiphysis of a growing child Fractures Tips of the scapula
What is the half life of Tech 99?
6 hours
This means you cannot do the 24 hour phase with this bad boi
Say a bone scan lights up during phase 1 and phase 2 but not in phase 3.
What’s the interpretation?
This is indicative of likely cellulitis
Name a way to test between charcot disease and osteomyelitis via imaging.
Ceretec scan or Indum 111 scan.
Indium-111 and Ceretec scan tags WBC’s
What does indium-111 tag?
WBC
Ceretec scan does the same
What does Indium-111 test for?
Highly sensitive and specific for acute soft tissue and osseous infections.
What does gallium-67 test for?
Acute inflammation and infection
How long does it take for gallium-67 test to work?
2-3 days, it localizes a little better than Indium-111
However, it is very expensive.
Why would you use a Tech-99 scan with a Galium-67 scan?
It helps to differentiate between Acute osteomyelitis, chronic osteomyelitis, and septic arthritis.
Can further be used to differentiate between fractures, acute cellulitis, and charcot.
What causes increased signal intensity in a T1 image?
T1 is the Fat image.
Fat lights up with increased signal intensity here.
What causes an increased signal intensity in a T2 image?
T2 is the pathological image.
Fluid, infection, inflammation, and tumors light up here.
What does the FIIT mnemonic describe with T2 imaging?
Describes the four things that generally have an increased signal intensity on T2 imaging. Fluid Infection Inflammation Tumor
For MRI what are the indications for STIR imaging?
Useful for the evaluation of edema in high lipid regions, such as bone marow.
Also for evaluating cartilage.
What is Fat saturation imaging used for?
Evaluating fat…
What is gradient echo imaging also known as?
Steady state magnetization
What is Gradient echo used for?
Joint imaging
What are the two uses for gadolinum?
NOTE THIS IS DIFFERENT THAN GALLIUM
Intravenous use: Distributes to places with increased vascularity such as neoplasms, inflammations, and the walls of abscesses.
Intraarticular use: Tests the cartilage integrity.
How will a stress fracture appear in T1 imaging?
Linear zone of decreased signal intensity surrounded by a less defined area of signal intensity.
How will a stress fracture appear in T2 imaging?
Linear zone of decreased signal intensity surrounded by an increased signal intensity due to edema.
How will a stress fracture appear in STIR imaging?
Increased signal intensity because fatty bone marrow is suppressed.
How will osteomyelitis appear in T1 imaging?
Break in cortex with decreased signal in the bone marrow.
How will osteomyelitis appear in T2 imaging?
Break in cortex, increased signal intensity in the bone marrow!!
