S1_L2_MSKI - 4-7 Flashcards
NEUROIMAGING CT scan (2)
structural
functional
Demonstrate microanatomy and macroanatomy of the brain
● Structural Imaging
Displays the activity of the brain based on
metabolic activity
● Functional Imaging
Usually given a contrast media to
light up hyperactive areas
functional imaging
More metabolic activity, __ in funcctional ikmaging
more lightne up
Diagnosis of lesions that are too small to
be detected is what type of neuroimaging
functional imaging
Indirect imaging of the brain by injecting
air in the ventricular system
Ventriculography
used for patients with
hydrocephalus
Ventriculography
Very invasive as it injects air into the brain
Ventriculography
Demonstrates blood vessels in and
around the brain
● Cerebral Angiography
Indirect imaging of the brain
● Cerebral Angiography
cerebral angiography is _ imaging of the brain
indirect
If there are occlusions c pt c stroke, you
can see where it is cut off in _
cerebral angiography
Identifies blood clots or thrombosis,
hemorrhage
cerebral angiography
When _ is seen due to contrast
media leaking, this represents a _
haziness, hemorrrhagic stroke
CT scan used for neuroimaging, when
1970s
CT + Nuclear medicine when
1980s
Single-photon emission CT (SPECT) when
1980s
Positron emission tomography (PET) when
1980s
Uses radioactively labeled chemicals for functional imaging of the brain
1980s
CT or MRI? Modality of choice for acute settings due to the short scanning times.
CT
CT or MRI? Detects changes in fluid content, ischemia, edema and
hemorrhage more accurately
MRI
CT or MRI? Axial Slice: Most commonly used for diagnostic purposes
CT
CT or MRI? Best
view of the ventricular system
ct
CT or MRI? Best view for spinal cord and brainstem
ct
Most commonly used for diagnostic purposes
Axial Slice
Best
view of the ventricular system
coronal slice
Best view for spinal cord and brainstem
sagittal slices
displays changes in blood flow through the paramagnetic properties of
Hgb or use of contrasts
Functional MRI (fMRI)
Demonstrates ischemia
immediately following its occurrence
Functional MRI (fMRI)
used in staging of stroke crucial in deciding treatment
Functional MRI (fMRI)
Not recommended for traumatic cases
mri
gray matter has a _ than white matter
because the nerve cell bodies are in the gray matter.
higher signal intensity
SIX BRAIN IMAGES in CT scan
cross
star
happy
sad
worms
coffee beans
The brain may be scanned in all _ orthogonal planes
3
CT scan: gray matter
Bright (more radiodense)
CT scan: white matter
less brighter than gray
CT Scan: CSF
dark more radiolucent
CT scan: bones
bright
ct scan subcutaneous fat
dark
MRI (T1) white matter
bright
MRI (T1) gray matter
dark (lower signal intensoty)
MRI (T1) bones
dark
MRI (T1) csf
dark
MRI (T1) subcutaneous fat
bright
MRI (T2) gray matter
bright (higher signal intesnity)
MRI (T2) white matter
dark
MRI (T2) bones
dark
MRI (T2) csf
bright
MRI (T2) subcutaneous fat
dark
A limb is made up of lesser wings or
sphenoid, a petrosal portion of temporal
bone
the cross
_ of the skull contains the anterior,
middle, and posterior cranial fossa
base
base of the skull contains:
anterior,
middle, and posterior cranial fossa
In the middle cranial fossa, the
_ lobe will be seen
temporal
A limb is made up of _ and _
lesser wings or
sphenoid, a petrosal portion of temporal
bone
Slice just above the base of the skull
star
Circle of Willis is seen, more evident in a contrast enhanced CT, what shape
star
Cut above the previous cut (star)
mr happy
eyes in mr happy is __
anterior horn of the lateral ventricles
mouth in mr happy is __
Quadrigeminal cistern
Down turned lips: posterior horns of the
lateral ventricle: what shape
mr sad
Down turned lips in mr sad
posterior horns of the
lateral ventricle
The (Back-to-Back) Worms what shape
mr sad
The (Back-to-Back) Worms, what part of brain
lateral ventricles
Cut almost at the vertex of the skull
the coffee beans
Sees the brain parenchyma
the coffee beans
Grey matter is denser than white matter. it appears whiter
due to its _
higher radiodensity
t or f If you suspect your relative has a stroke, go to the nearest hospital with
a CT scan because it is part of the protocol for treatment in the acute setting.
t
Non-invasive imaging technology that produces
three-dimensional detailed anatomical images
MAGNETIC RESONANCE IMAGING
It is often used for disease detection,
diagnosis, and treatment and monitoring
MRI
It is based on sophisticated technology that excites and detects the
change in the direction of the rotational axis of protons found in the
water that makes up living issues.
MRI
MRI is based on _ technology that excites and detects the
change in the direction of the_ found in the
water that makes up living issues.
sophisticated, rotational axis of protons
ct scan how many mns
10 mins
● mri is Not ideal for claustrophobic patients t or f
t
Sound of machine is loud, so patients are
given noise-canceling headphones in __
MRI
Cross-sectional imaging technology that uses a
magnetic field and radiofrequency signals to cause
hydrogen nuclei to emit their own signals which are
then converted to images by a computer
MRI
The energy emitted varies according to the
tissues form which the signal emanates which allows the MRI to distinguish
between different types of tissues
MRI
These are different processes that are related to the return of
protons to alignment with the magnetic field.
T1 & T2 PHENOMENA
t1 and t2 phenomena are different processes that are
related to the return of _to alignment with the _
protons, magnetic field
Following the RF pulse, 2 things happen:
○ The protons gain longitudinal magnetization or realign with the
magnetic field
○ The protons lose their transverse
magnetization
In MRI, the contrast between tissues in the
images is created based on differences in T1 and T2 and _,
or number of hydrogen nuclei in the different tissues
proton density
Two parameters are most important in
creating for creating contrast in the image:
TR (Time to Repetition)
TE (Time to Echo)
Time at which the RF pulse is repeated to again displace the atoms
○ TR (Time to Repetition)
■ Time at which the signal is captured
○ TE (Time to Echo)
Imaging protocols of events during image
acquisition
sequence
T1 is more sensitive to __
fat
● Short TE and TR times:
t1
in _ phenomena, The signal is caught __ and tissues that
rapidly recover their longitudinal
magnetization such as fat give rise to _ signal intensities
t1, early, high
When __ TE is employed, tissues that are slow to recover
their longitudinal magnetization such as tissues with high
__ content render __ signal intensities. what phenomena?
short, high, low, T1
Long TE and TR times
T2
T2 images are measured __ in the process so
tissues that have high water content renders high signal intensity
Late
Tissues with _ content (gives up energy fast) gives rise to
__ intensity on T2
fat, low signal
Brighter images for structures with higher water content in what phenomena
t2
Darker images for structures with higher fat content in what phenomena
t2
T1 vs T2: Measures energy early
T1
T1 vs T2: Selectively images structures that to not readily give up energy
T2
T1 vs T2: Provides images of good and tonic detail, displaying
tissues in a fairly balanced manner
T1
T1 vs T2: High signal intensity – WATER
T2
T1 vs T2: Measures energy later
T2
T1 vs T2: High signal intensity – FAT
T1
T1 vs T2: Low signal intensity - fat
T2
T1 vs T2: Low signal intensity – WATER
T1
