WEEK 3: Radio of the Skull, Brain and Spine Flashcards
Energy used to produce the image must be capable of
penetrating tissues. T or F?
T
High frequency sound waves
ultrasound
basically an electrode pair inside a glass
vacuum tube.
Xray machine
Anode or cathode? Electric current passes through the filament, heating it
up
o Heat sputters electrons off the filament surface
cathode
Anode or cathode? o Flat disc mode if tungsten.
o Draws electrons across the tube.
anode
negative part of the xray tube?
Cathode
Radiolucent or radiopaque?
o Transmitted radiation
▪ Passes through the patient and interacts with the
detector to create the image
Radiolucent
absorbed radiation or scattered radiation? Interacts with the tissues of the patient depositing
energy in tissues.
absorbed
what is the density of water?
1
white to black on Xray?
Bone Soft tissue Water Fat Air
T or F? the thicker the object the more radiopaque it is.
T
▪ Passes through the patient, but changes its original
path, leaving the patient along a different course
▪ Can degrade the quality of the image
▪ Can be exposure source to personnel
absorbed radiation or scattered radiation?
scattered radiation
Radiography is usually used for
- Broken bones
- Cavities
- Foreign objects
- Lungs
- Blood vessels (angiography)
- Breasts (mammography)
liquids that absorb x-rays more effectively than surrounding tissue
▪ To bring organs in the digestive tract into focus typically a barium compound will be swallowed or introduced
Contrast media
gadolinium based agents with T1 relaxation time shortening effects
MRI
micro-bubbles which have higher echogenicity compared to human tissue are injected into the patient’s vein.
Ultrasound
A narrow beam of x-ray scans across a patient in synchrony with a radiation detector on the opposite side of the patient.
• Internal structure of an object is reconstructed from multiple projections
CT
uses of angiography
Diagnosis of primary vascular disease
• Pre-operative definition of vascular anatomy
• Diagnosis of vascular complications
A quantity used in CT to express CT numbers in a standardized and convenient form
Hounsfield unit
Created by and named after Sir Godfrey Hounsfield
Radiodensity of distilled water at STP
0 HU
Radiodensity of air at STP
-1000 HU
HU of fat
-200 - -50
Aka grey-level mapping, contrast stretching, histogram modification
Windowing
o Can detect diffuse and focal changes
o Bone window can detect fracture
what CT?
Plain CT
When to use MRI?
• Soft tissue details in areas such as the brain, internal pelvic organs, and joints (such as knees & shoulders) can often be better evaluated by MRI.
• In pregnant women, while CT can be performed safely, other imaging exams not involving radiation, such as ultrasound or MRI, are preferred but only if they are likely be as good as CT in diagnosing your condition.
• A person who is very large may not fit into the opening of a conventional CT scanner or may be overweight the limit – usually 450 lbs. – for the moving table (gantry)
Gantry/table won’t move if px is >450 lbs.
o Can detect and characterize focal lesions
o Majority of pathological lesions have a predominantly arterial supply, and thus “enhance”
What CT
Contrast CT
Process in which the image greyscale component of an image is manipulated via CT numbers
• Will change the appearance of the picture to highlight particular structures
• Brightness of the image is adjusted via window level
• Contrast is adjusted via the window width
windowing
CT is more versatile than X-rays and usually used for
o Presence, size and location of tumors o Organs in the pelvis, chest and abdomen o Colon health (CT colonography) o Vascular condition/blood flow o Pulmonary embolism (CT angiography) o Abdominal aortic aneurysms ( CT angiography) o Bone injuries o Cardiac tissue o Traumatic injuries o Cardiovascular disease
- Does not use ionizing radiation
- Images are created using radiofrequency energy emitted by hydrogen protons when strong magnetic fields generated around a patient are manipulated
MRI
Identify if CT or MRI? x-ray beams
CT
Identify if CT or MRI? fast scan time
CT
multiplanar: CT or MRI?
BOTH
superior soft tissue differentiation: CT OR MRI?
MRI
density: CT or MRI?
CT. MRI y intensity
Lower time to relax, lower time to emit ratio. T1 or T2?
T1. T1 has lower TR and TE
Grey matter is both isointense in T1 and T2. T or F?>
t
White matter, because of their fat content (rich in myelin, lipid filled) is bright on T1 and hypointense on T2. T or F?
T
Ventricles which is mainly composed of water is black on T1 and white on T2. T or F?
T. World War 2 mnemonic WW2, water is white on T2
White areas on sulci are CSF which are in the subarachnoid space.
T
why is blood both black on T1 and T2?
Blood are both black on T1 and T2 because of the principle of how you measure, blood flows so when it’s measured the molecule measured is no longer there after few secs.
identify the intensity in T1 and t2: gray matter
isointense on T1 & T2
identify the intensity in T1 and t2: White matter
bright on T1, dark on T2
identify the intensity in T1 and t2: Ventricles/CSF
black on T1, white on T2
identify the intensity in T1 and t2: Blood vessels (flowing blood)
black on T1 & T2.
Gray Matter o Higher blood flow o Isointense on T1 ▪ Darker/brighter than ventricles? o Isointense on T2 ▪ Darker/Brighter than ventricles?
Brighter;
Darker
• CSF
o 99% water
o Black on T1
o White on T2
is this true?
T
Appearance of all cortical bone in all sequences?
DaRK
is fat bright or dark in T1?
bright;
T or F? Brain lesions usually produce edema?
T
Most lesions are dark on T2. T or F?
F. Bright
T or F? We always look on T2 first, if there’s any funny looking on T2 we confirm it on T1
T.
Identify the image characteristics on ultrasound: Air
poor qulaity d/t scatter
Identify the image characteristics on ultrasound: water
anechoic (black)
Identify the image characteristics on ultrasound: blood
Anechoic (black)
Identify the image characteristics on ultrasound: fat
Hypoechoic to isoechoic (dark to lighter gray)
Identify the image characteristics on ultrasound: muslce
isoechoic (lighter gray)
Identify the image characteristics on ultrasound: bone
Hyperechoic (bright white)
Usual uses of Utz?
• Abnormalities in the heart and blood vessels
311-026 RADIOLOGY OF THE SKULL, BRAIN, & SPINE (1 OF 2) 8 of 15
• Pleural effusion and other collection quantification
• Organs in the pelvis and abdomen (e.g., pregnancy)
• Superficial neck
• Tendon/ligament tears and joint effusion
• Small superficial masses
• Neonatal brain
T or F?If you see a fluid structure like this and it’s intensified we call it posterior acoustic enhancement that’s a cyst.
T
Can detect a frequency shift in echoes, and determine whether the tissue is moving toward or away from the transducer
• For evaluation of some structures such as blood vessels or the heart
Doppler utz
why is the UTZ Not an ideal imaging technique for air-filled bowel or organs obscured by the bowel
UTZ waves are disrupted by air or gas
What fontanel?
o persist until 1.5-2y
o becomes bregma
anterior (frontal) fontanel
What fontanel?
o persist until ~3mos
o becomes lambda
posterior (occipital) fontanel
What fontanel?
o persist until 6mos
o becomes pterion
anterolateral (sphenoidal) fontanels
What fontanel?
o persist until 2y
o becomes asterion
posterolateral (mastoid) fontanels
what view of the skull? o non-angled lateral radiograph
o overview of entire skull
o does not attempt to highlight any region
lateral view
What view to use when there are facial fractures?
PA axial view
o Angled anteroposterior radiograph, used to evaluate for fractures and neoplastic change
o To visualize the petrous portions of the temporal bones, the dorsum sellae, and the posterior clinoid processes
▪ Visible in the shadow of foramen magnum
AP Axial View?
AKA AP Axial View?
Towne View
o Caudally angled posteroanterior radiograph, to better visualize the paranasal sinuses, especially the frontal sinus
o Petrous ridges are below orbits
PA Axial View
AKA PA Axial view?
Caldwell view
On Caldwell view the orbits are above the overlapping maxillary and petrous ridges. T or F?
T
o Angled posteroanterior radiograph
▪ Patient gazing slightly upwards
o To assess for facial fractures as well as acute sinusitis
o Petrous ridges are below maxillary sinuses
OCCIPITOMENTAL VIEW
AKA OCCIPITOMENTAL VIEW
Patient gazing slightly upwards
WATERS VIEW
o Back of patient is arched as far as possible so that the base of the skull is parallel to film
o Primarily taken to demonstrate sphenoid sinuses and zygomatic arches
Submentovertex view
Usually done to see zygomatic arch, mandibular symphysis and skull base lesions but never do this unless you clear the patient for a cervical spine fracture
Submentovertex view
For trauma, to check for the facial bone and the skull usually you do the lateral view and the water’s view and if you have one more you do an AP view.
• Intracranially it is formed by two layers:
o Outer endosteal layer
▪ Continuous with the periosteum
o Inner meningeal layer
▪ Continuous inferiorly with the spinal cord theca
Dura mater
ICA Segments?
Bouthillier classification: o Cervical segment o Petrous (horizontal) segment o Lacerum segment o Cavernous segment o Clinoid segment o Ophthalmic (Supraclinoid) segment o Communicating (Terminal) segment
Ophthalmic artery is a branch of the
cavernous segment
Vertebral artery segments
V1 (preforaminal)
Origin to transverse foramen of C6
V2 (foraminal)
From transverse foramen of C6 to the transverse foramen of C2
V3 (Atlantic, extradural or extraspinal)
From C2 to the dura
V4 (intradural or intracranial)
From dura to their confluence, from basilar artery
Origin: vertebral artery confluence
• Course: ventral to pons in the pontine cistern
• Branches: numerous to cerebellum and pons
• Termination: division into the two posterior cerebral arteries.
Basilar Artery
Arises from the anterior cerebral artery and acts as an anastomosis between the left and right anterior cerebral circulation.
• Demarcates the junction between the A1 and A2 segments of the anterior cerebral artery.
ACoA
Originates from the posterior aspect of the C7 (communicating) segment of the internal carotid artery and extends posterior medially to anastomose with the ipsilateral posterior cerebral artery and from part of the circle of Willis.
• Branches:
o Many fine, scarcely visible, perforating branches
o Largest perforating branch is called the premamillary or anterior thalamo perforating artery
• Vascular territory
o Posterior part of the optic chiasm and optic tract
o Posterior part of the hypothalamus and mammillary bodies
• Part of the thalamus
PCoA
The vein that connects superior sagittal sinus to inferior sagittal sinus
Vein of Trolard
The internal cerebral vein, the biggest one
Vein of Labbé
The most common cause of subarachnoid hemorrhage
is trauma.
Most common non-traumatic cause of SAH is
ruptured aneurysm.
“3H” we are looking for in the imaging tumor
Hemorrhage
Hydrocephalus
Herniation
Posterior acoustic shadowing vs posterior acoustic enhancement
posterior acoustioc shadowing means that it is a stone or calcification kasi ung nasa liko nya would be black.
posterior acoustic enhancement means it is a cyst, nagiging white ung nasa likod nya.
what are the membranous part of the cranium? (4)
- Paired frontal bones
- Paired parietal bones
- Squamous parts of the temporal bones
- Interparietal part of occipital bone
what are the cartilaginous part of the cranium? (4)
- Ethmoid bone
- Sphenoid bone
- Petrous parts of the temporal bone
- Occipital bone surrounding the foramen magnum
connective tissue patches where more than two sutures meet
fontanels
suture that separates paraietal to temporal?
squamous suture
suture that separates the parietal to occipital bones
lambdoid
metopic suture?
separates 2 frontal bone
On _______ view the orbits are above the overlapping maxillary and petrous ridges.
caldwell view
If looking for fractures in the occipital bone or the petrous portions use ________ rather than AP view or other views
Towne view
To assess for facial fractures as well as acute sinusitis
o Petrous ridges are below maxillary sinuses
Waters view
T or F? For trauma, to check for the facial bone and the skull usually you do the lateral view and the water’s view and if you have one more you do an AP view.
T
aka pachymeninx?
Dura mater
aka leptomeninx
arachnoid mater and pia mater
Spaces where the pia mater and arachnoid membrane are not in close approximation.
Subarachnoid cisterns
connect cortex with other areas in CNS; may be efferent (motor) or afferent tracts (sensory)
projection tracts
tracts connecting different areas in the same hemisphere (intrahemispheric tracts)
association tracts
▪ arcuate fasciculus
▪ superior and inferior occipito-frontal fasciculi
▪ cingulum, uncinate and inferior longitudinal bundle
these are examples of?
association tracts
o tracts connecting the same cortical area in opposite hemispheres
commisural tracts
• encloses the third ventricle
• connected above and in front with the cerebral hemispheres
• connected behind with the mid-brain
• upper surface is concealed by the corpus callosum
• covered by a fold of pia mater
o named the tela choroidea at the third ventricle
• inferiorly it reaches to the base of the brain
diencephalon
neural arch is composed of?
pedicles and lamina
what are the 4 processes in the vertebra?
o Transverse processes
o Inferior articular processes
o Superior articular processes
o Spinous process
- Large anterior cylindrical portion
* Predominantly responsible for bearing the weight of the spine and body above it
vertebral body
o Short, thick bilateral processes from the posterolateral corner of the vertebral body
o Form lateral walls of vertebral foramen and join with lateral aspects of laminae posteriorly
Pedicle
Bilateral, flattened plates that extend posteromedially from posterior margin of pedicles
o Meet in the midline forming the posterior wall of the vertebral foramen
Lamina
Project posterolaterally from where the pedicles and laminae fuse
transverse process
what vertebra?
o Small, oval-sized vertebral bodies
o Relatively wide vertebral arch with large vertebral foramen
o Relatively long, bifid inferiorly pointing spinous processes
o Transverse foramina protecting the vertebral arteries and veins
typical cervical
what are the typical and atypical cervical vertebra?
Typical: C3 to C6
Atypical: C1, C2, C7
- Articulates with occiput to allow flexion, extension, and lateral flexion of head
- Transverse ligament: holds the dens of the axis against the anterior arch.
atlas
what view best appreciates the atlanto-axial joint
Open mouth AP
what type of atlas fracture is jefferson fracture?
Type 3
Communicated lateral mass fracture what type of atlas fracture?
type 4
Plays an important role in rotation of the head with the majority of movement occurring around the dens at the atlanto-axial joint
Axis
Spinous process ends in a rounded tubercle (not bifid)
• Transverse foramina are small, and do not transmit the vertebral artery
• Anterior tubercles are small
C7
standard projections in cervical spine radiography?
- AP
- Lateral
- Odontoid
- AP oblique
- PA oblique
additional view in cervical spine radiography
- Cervicothoracic view (Swimmer’s view)
- Modified lateral
- Flexion-extension lateral
- Fuchs view
85% to 90% of spinal injuries are evident on this view:
Lateral
85% to 90% of spinal injuries are evident on this view:
AP
Demonstrates intervertebral foramina of side positions further from the image receptor.
AP oblique
To visualize the C7/T1 junction
cervicothoracic view (swimmer’s view)
Non-angled AP radiograph of C1 and C2
Fuchs views
most common MOI of cervical spine fracture?
flexion
MOI of hangman’s fracture?
hyperextension
MOI of jefferson’s fracture?
axial loading/compression
• Traumatic spondylolisthesis of the axis
• Involves pars interarticularis of C2 on both sides
• Results of hyperextension and distraction
• Neurological impairment is seen only in 25% of patients
• Radiologic fractures:
o Bilateral lamina and pedicle fracture at C2
o Usually associated with anterolisthesis of C2 on C3
o Extension of the fracture to the transverse foramina should be sought, raising the possibility of vertebral artery injury.
Hangman Fracture
- Fractures of the spinous process of a lower cervical vertebra
- Often these injuries are unrecognized at the time and only found incidentally years later when the cervical spine is imaged for other reasons
Clay shovelers fractures
o Medium-sized, heart shaped vertebral bodies
o Medium-sized vertebral canal
o Prominent transverse processes with costal facets
o Long spinous processes angulating downwards.
Thoracic vertebra
what are the typical thoracic vertebra?
t2 to t8
- A.k.a seatbelt fracture
- Flexion-distraction type injuries of the spine that extend to involve all thre spinal columns
- Unstable injuries and have a high association with intra-abdominal injuries
- Most commonly occurs about the upper lumbar spine (with the thoracolumbar junction accounting for 50% of cases), but it may be observed in the mid lumbar region in children.
Chance fractures
A type of compression fracture related to high-energy axial loading spinal trauma that results in disruption of the posterior vertebral body cortex with retropulsion into the spinal canal.
Burst Fracture
