Ch 5/6 Reading Questions Flashcards
(32 cards)
MRI measures energy emitted from hydrogen nuclei after their stimulation by what type of signals:
radiofrequency
Return to longitudinal magnetization is called
T1 frequency
The faster the return the ___________ the signal from the tissue
stronger
T1 is taken at a time during the sequence when the difference between ______ and _____ is most noticeable
fat and water
What tissue gives the highest signal in T1 and therefore is the brightest white?
fat
___
is slow to give up energy and therefore gives a high signal intensity on T2 sequences
free water
T2 images are ___ and display less ___ ___.
grainer and spatial resolution
Tissues with high signal intensity under T1
yellow marrow, fat, and acute hemorrhage
Tissues with high signal intensity on T2 image sequence
soft tissue tumors, synovial fluid, inflammation, and CSF
What does MRI do best (general and specific pathologies)?
-disc herniations
-soft tissue detail
-stage neoplasm and identify tissue invasion
-detect changes in bone marrow
MRI Limitations
-contrainidcated for pts with pacemaker (or other metal)
-cost
-staying still for a long time
-sedation may be needed
-claustraphobic
-lengthy imaging
Ultrasound is a ___ _____ imaging method based on _____ waves.
cross sectional
sound
How many ultrasound imaging types can PTs use in therapy?
2
Ultrasound _____ converts the electricity from the pulser into sound energy
transducer
Attenuation and processes for it
reduction in the amount of ultrasound signal
-reflection, scattering, absorption, and refraction
Factors for refraction
-smoothness of tissue
-angle of reflection
-tissue type
-difference in impedance between tissue types
Doppler is used to measure the ____ in an artery or vein. Power doppler is used more frequently in Physical Therapy because it measures the ________
of blood flow without estimating its _____
nor is it dependent on the ______ of the flow.
blood flow, volume, velocity, direction
Typically palpation is done prior to ultrasound imaging yet Sonopalpation is palpation done through the ___ during application.
transducer
The echogenic properties of tissue is called the “echogenicity” of a tissue. Structures that reflect much energy are said to be _______. When there is no reflection tissue may be referred to as _____.
hyperechoic, anechoic
The echogenic properties of tissue is called the ______ of a tissue. Therefore the use of hyper means brighter and hypo means ____ brightness.
echogenicity, reduced
Two terms for planes of ultrasound imaging include _____ which means along the length of a structure and ____ which means a cross section or axial image of the structure.
longitudinal, transverse
Characteristic of bursa ultrasound imaging
a potential space with minimal fluid shows up as a hypoechoic line
Characteristic of bone ultrasound imaging
Can not penetrate and therefore returns all waves
Characteristic of ligaments ultrasound imaging
hyperechoic compared to muscle with a compact parallel fiber pattern
