Types of Imaging Flashcards
During an ultrasound, When moving _________ the transducer, sound waves reflected off of blood cells arrive at transducer _________
toward; faster
During an ultrasound, When moving _________ the transducer, sound waves reflected off of blood cells arrive at transducer _________
away; slower
What does ultrasound provide information on?
- presence of blood flow
- direction of blood flow
- gross circulation abnormalities
What are the characteristics of blood flowing through a narrowed foramen during ultrasound?
increased speed and turbulence
Limitation of CT scan
- inability to distinguish small areas of different tissues
- radiation exposure
Characteristics of T1 weight MRI
measures energy from structures that give up energy quickly (fat)
- good anatomic detail
- tissues with high water content appear darker (CSF)
- fat is brighter and water (CSF) is darker
characteristics of T2 weighted MRI
measures energy from structures that give up energy slowly (water)
- fat appears darker, water (CSF) is brighter
- grainer, less spatial resolution
- good for identifying inflammation
Which weighted image is good for identifying inflammation?
T2
In which weighted image is CSF low? high?
low = T1
high = T2
What is a MRI angiography sensitive to?
changes in bone marrow
- dx of bone tumor
- stress fx
- avascular necrosis (AVN)
What is the general indication of nuclear imaging?
testing function of tissues
- intent of diagnosis
What does increased and decreased uptake mean on a bone scan?
increased uptake - osteoblastic
decreased uptake - osteoclastic
What are the 3 phases of a bone scan?
1st Phase: flow study (immediate)
2nd Phase: blood pool (30 minutes)
3rd study: delayed (2-4 hours)
Advantages and disadvantages of a bone scan
Advantages
- High sensitivity for changes in bone metabolism
Disadvantages
- Low specificity
- Poor anatomic detail
contraindications of a bone scan
- pregnancy
- currently breast-feeding
