disclaimer - meant for educational purpose only .

1. BY : Dr . Sameeha Khan
(MDRD)
Part 1

2.  Understanding vascular anatomy is fundamental
to neuroimaging.
 About 18% of the total blood volume in the body circulates in
the brain, which accounts for about 2% of the body weight.
 The blood transports oxygen, nutrients, and other substances
necessary for proper functioning of the brain tissues and carries
away metabolites.
 Loss of consciousness occurs in less than 15 seconds after
blood flow to the brain has stopped, and irreparable damage to
the brain tissue occurs within 5 minutes.
 Cerebrovascular disease or stroke, occurs as a result of
vascular compromise or haemorrhage and is one of the most
frequent sources of neurologic disability.

3.  Part 1 –
 Aortic arch and great vessels
 Carotid arteries
 Circle of Willis
 Part 2 –
 Cerebral arteries
 Posterior fossa arteries – vertebrobasilar
system

4. 1. Conventional intra-arterial angiography –
DSA system - techniques of image
acquisition
 Standard radiographic projections
 carotid angio-
▪ Lateral projection – centered on pituitary fossa
▪ AP view – with petrous ridge projected over the roof of
orbit
▪ I/L anterior oblique – for aneurysms in SAH
 Vertebral angio –
▪ lateral , half-axial ( Towne’s) and AP – petrous ridge
superimposed on lower border of orbit

5. 2. Computed tomography angiography
3. Magnetic resonance angiography
I. Time of flight – inflow of unsaturated spin
II. Phase contrast – accumulation of phase shifts proportional to flow
velocity
III. Contrast enhanced MRA
 Intracerebral vessels -3D TOF MRA is technique of choice
 Circle of willis – single slab 3D TOF
 Larger part of intracranial circulation – 3-4 multiple overlapping
slabs ( MOTSA )
 Phase contrast sensitive for slow flow – used for cerebral veins
4. Doppler ultrasound

6. Starts from aortic arch :
Aortic arch
Innonimate
artery
Left
common
carotid
Left
subclavian

7. 3 . Innonimate artery
10. Left subclavian
artery
15. Left common
carotid artery

8.  A.k.a Brachiocephalic trunk .
 1st vessel arising from the aortic arch .
Innonimate
artery
Right
subclavian
artery
Right
common
carotid artery

9. 4. Right subclavian
artery
5. Right common
carotid artery

10. Right subclavian artery
Right
vertebral
artery
Internal
mammary artery
Thyrocervical
trunk
Costocervical
trunk

11. 6. Right vertebral artery
9. Internal mammary
artery
16. Thyrocervical trunk
16

12.  Common arch anomaly
 0.5-1% of all cases
 Here it is the last
brachiocephalic vessel arising
from aortic arch -4th branch
 Often asymptomatic – 10 % of
people can have dysphagia
lusoria.
 Right common carotid arises
directly from arch – first branch

13. Barium studies – fixed narrowing
of esophagus at the level of arch
without mucosal deformity –
bayonet deformity

14.  1st Branch of right subclavian artery
 Right vertebral artery dominant -25%
 Anomalous origin – uncommon

15.  Arises from proximal IA
 Only cervical part as it arises caudally

16.  RCCA – directly from aortic arch ( when
right SCA is aberrant )
RCCA
RSCA

17.  2nd major branch from aortic arch
 Thoracic and cervical part –in thoracic it travels upwards throu
superior mediastinum to the level of left sternoclavicular joint and
continues as cervical
15.Left common
carotid
CCA bifurcates into ICA and
ECA at midcervical level C3-
C6 level.

18. LCCA- common
origin with IA

19.  LCCA – hypoplastic
or absent – here the
ECA and ICA arise
directly from aortic
arch
 Non bifurcating
carotid artery –
origin to all the ECA
branches

20.  Last branch from aortic arch
 Major branches -
Left subclavian artery
Left vertebral
artery
Internal
mammary
Thyrocervical
trunk
Costocervical
trunk

21.  First branch of left subclavian artery
 Dominant in 50-60%
 In 25% right and left VA are equal in size
11.Left vertebral artery
14.Left internal
mammary

22.  Left vertebral artery –directly from aortic arch
-5% ( nondominant )

23. RSCA
LSCA
Innominate
artery
LCCA
RCCA
RVA
LVA

24.  Course - Runs within a
fascial plane – the carotid
sheath –also contains IJV
and vagus nerve, vein
lateral to artery , nerve
between the two
 Runs obliquely upwards
from the level of
sternoclavicular joint to the
level of thyroid cartilage
 Bifurcates at the level of C3-
C5 into external and
internal carotid artery
 At bifurcation ICA usually
lies posterior and lateral to
the ECA

25.  Smaller of the 2 carotids.
 Origin anterior and medial to ICA.
 Supplies the extracranial structures.
 Branches –( Sister Lucy’s Powdered Face
Attracts SO Many Medicos )
Internal carotid artery
External carotid artery
Common carotid artery

26. External carotid artery
Anterior
Superior
thyroidal
Lingual
Facial
Posterior
Occipital
Posterior
auricular
Medial
Ascending
pharyngeal
Terminal
Maxillary
Superficial
temporal

27. ECA – branches

28. Superior thyroid artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular
artery
Ascending
pharyngeal artery
Early arterial phase of CCA angiogram

29. Late arterial phase of CCA angiogram
Posterior auricular
artery
Occipital artery
Facial artery
Lingual artery
Superficial temporal
artery
Maxillary artery
Transverse facial

30.  Internal maxillary artery-
 Runs forward deep to the
mandible.
 Branches – inferior
alveolar, middle meningeal,
deep temporal , accessory
meningeal , sphenopalatine
, infraorbital , descending
palatine, muscular
branches.
 Middle meningeal artery –
runs superiorly crosses STA
on lateral projection thro
foramen spinosum.
 Supplies – dura and inner
table of skull.

31.  On angiogram should be
differentiated from middle
meningeal artery –
characteristic hairpin turn
of STA over zygomatic
process
 Supplies –part of scalp
and ear.
 Branch – transverse facial
artery
 Variant – TFA may arise
from ECA directly
STA
Middle meningeal artery
hairpin turn of STA

32. Oblique view – MRA
Vertebral artery
Thyrocervical trunk
Facial artery
Lingual artery
Superficial
temporal artery
Occipital artery
Maxillary artery

33. Straight AP view – MRA
Superficial
temporal artery
Hairpin turn of
STA
Maxillary artery
Facial artery
Lingual artery
Vertebral artery
Middle meningeal
artery

34. Late arterial phase – prominent vascular blushes in the
mucosa of sinuses , nose ,orbit , oropharynnx -
not to be confused with vascular malformations
Oropharynx mucosal
blush
High nasopharynx
mucosal blush
Orbital mucosal
blush
Nasal conchae
septal blush
Palatal
mucosal blush

35. Maxillary artery
• Middle meningeal
artery
• Foramen rotundum
artery
• Accessory meningeal
• Vidian artery
• Ant / mid deep
temporal
ICA
• Ethmoidal br of
opthalmic artery
• Inferlolateral trunk
of ICA
• Inferolateral trunk
• Intratemporal ICA
• Opthalmic artery

36. • Occipital
• Ascending
pharyngeal artery
• Ascending
pharyngeal artery
• Facial artery
• Posterior auricular
artery
• Vertebral
• Vertebral C3 level
• ICA (petrous and
cavernous )
• ICA (opthalmic
artery)
• ICA (stylomastoid
artery)

37. Intima – white endoluminal line
Media – darker line underneath
Adventitia –thick peripheral white line
• Laminar flow in lumen of
proximal ICA
• Velocity of flow increases
towards the aorta ( 9 cm /
sec for each cm of distance
from the carotid
bifurcation)

38. Left CCA
Right CCA
Internal carotid-
carotid bulb
ECA
3-D CTA
• Origin -Lateral to
ECA.
• Can be divided into
number of segments
between the bulb
and its bifurcation
into MCA and ACA.

39. Cervical
Intraosseous
/ petrous
Lacerum
Cavernous
Intracranial /
supraclinoid
Opthalmic
Communicating

40. ICA
Carotid bulb
Petrous
Cavernous
Supraclinoid
Cervical
Oblique DSALateral DSA

41.  Distal 2-4 cm of CCA
 Bulbous dilatation of ICA
origin
 Complex flow –
 flow distal to bulb is laminar
 Flow reversal within posterior
bulb
 Thinner media and thicker
adventitia containing many
receptor endings of
glossopharyngeal nerve

42.  No narrowing
 No dilatation
 No branches
 No tapering
Course – crosses
behind and
medial to ECA
ICA
ICA
ECA

43.  10%- ICA
originates
medial to ECA
 Anomalous ECA
branches arises
from cervical
ICA
 Persistent
embryonic vesels
may anastomose
with
vertebrobasilar
system
ICA
ECA

44. Vertical
•2 subsegments joined at genu
•Short vertical segment – anterior to IJV
•Genu – petrous ICA turns anteromedially in front of cochlea
•Longer horizontal segment
ICA –intraosseous
1. enters carotid canal
in petrous temporal
bone.
2. Surrounded by
sympathetic plexus
3. exit at petrous apex
Horizontal
Genu

45. Axial NECT inferior to superior ( bone window )

47. Petrous segment of ICA
• Branches supply middle earIntrapetrous
• Inconstant
• Throu Foramen lacerum and vidian
canal
• Anastomose with branches of ECA
(Recurrent br of greater palatine)
Vidian artery
(artery of Pterygoid
canal )
• Important branch –tympanic cavity
• Supplies middle and inner ear
Corticotympanic
artery

48. Foramen lacerumVidian canal

49. Aberrant course
•Posterolateral course thro temporal bone
•ICA parallel jugular bulb
•Inferior aspect of cochlear promontory
•Reduced diameter
•Visible pulsatile mass in hypotympanum
•Bony plate separating ICA from tympanic
cavity absent
•Vertical segment of carotid canal absent
Normal course of ICA
•Anteromedial course thro temporal bone
•ICA anterior to IJV
•In front of cochlea
• 2 segments

50. ICA courses adjacent to jugular bulb ICA traverses the hypotympanum
Bony plate along tympanic portion of ICA absent
Axial multidetector
CT images
Aberrant ICA
d/d glomus tympanicum
paraganglionoma
biopsy – disastrous

51. Rare- 0.48%
Intrapetrous embryonic vascular
channel stapedio-hyoid artery
Origin – petrous ICA/abICA
Course – passes throu the
footplate of stapes. Enclosed
within a bony canal near cochlear
promontary
Termination – as middle
meningeal artery
CT- absentI/Lforamenspinosum
d/d – glomus tumor
Recognised before surgery

52. Small segment that extends from petrous apex above foramen lacerum curving
upwards towards and lies extradurally until it reaches petrolingual ligament after
this it becomes the cavernous segment
Covered by trigeminal ganglion
No branches

53. Carotid angiogram

54. C4 segments
1. Ascending (posterior vertical )
2. Posterior genu
3. Horizontal
4. Anterior genu
5. Anterior vertical
Branches
Meningohypophyseal artery
Inferolateral trunk
Small capsular branches
1
Starts from petrous apex
Terminates at its entrance into
intracranial subarchnoid space
adjacent to anterior clinoid process.
Covered by trigeminal ganglion
posteriorly.

55. Carotid
angiogram

56. Axial CT
Posterior genu as it
courses anteromedially
into the cavernous sinus
ICA courses along the
bony grooves of carotid
sulcus along the
basisphenoid bone
• Throu cavernous sinus proper turns superiorly
• Form grooves under anterior clinoid process
• Anterior genu of ICA .
• Curve upwards towards dural ring
• Enter subarchnoid space
Posterior genu
Carotid sulcus
Anterior genu

58. C4 within cavernous sinus

59. Menigohypophyseal artery
•Posterior trunk
•Arises at junction of c4 and
c5
•Supplies –
•pituitary gland
•tentorium (artery of
Bernasconi and Cassinari )
•cavernous sinus
• clival dura
• cn3 n 4
•High quality D/FSA
•Enlarges to supply dural
vascular malformation /
neoplasm
Inferolateral trunk
• Lateral mainstream artery
• Arises – inferolaterally
from c4 segment
• Supplies –
• CN 3,4,6
• gasserian ganglion CN5
• cavernous sinus dura
• Anastomose with br of
internal maxillary artery .
Collaterals b/w ECA N
ICA
• DSA – lateral view
• Enlarged – vascular
neoplasm / malformation
/ collaterals to ECA

61. •Between proximal , distal dural rings of
cavernous sinus
•Ends as ICA enters subarachnoid space
near anterior clinoid process
•No important branches
•Unless OA arises within CS

62. Extends from distal
dural ring at superior
clinoid to just below
posterior
communicating artery
(PCoA) origin
Branches –
•Opthalmic artery
•Superior hypophyseal
artery
CECT
Anterior clinoid process C6

63. Origin –
• Intradural
•Antero-superior ICA
• Medial to anterior clinoid process
Course –
Anterior throu optic canal
Below optic nerve
Crosses superomedially over the nerve
Supply -globe
Gives off ocular , lacrimal , muscular
branches
•Anastomose with ECA

64. Mid arterial phase DSA
Lateral view MRA
Lateral DSA

65. Arises from posteromedial aspect of
supraclinoid ICA
Course – across the ventral surface of
optic chaisma
Terminates- pituitary stalk and gland
Supplies – anterior pituitary ,
Infundibulum , optic nerve and
chaisma
Anastomose - with hypophyseal
branch from the contralateral ICA
forms plexus – superior hypophyseal
plexus
DSA – usually not visualized if not
enlarged

66. Unruptured
superior
hypophyseal
aneurysm
Normally SHA
not easily seen

67. •Extends from below PCoA to
terminal ICA bifurcation.
•Passes between optic and
occulumotor nerve.
C7 segment branches
Posterior communicating
artery
Anterior choroidal artery
Lateral DSA
AChA
PCoA
3D CTA

68. •Arises – posterior aspect
of intradural ICA just
below anterior choroidal
artery
•Course – posterolaterally
above the occulumotor
nerve to join posterior
cerebral artery
•Branches – anterior
thalamoperforating
arteries
•Supplies – optic chiasma,
pituitary stalk , thalamus ,
hypothalamus.
Lateral late
arterial DSA
MRA

69. 1. Hypoplasia – 1/3 rd cases
2. Persistence of embryonic
configuaration ( fetal origin of
posterior cerebral artery ) 20 –
25%
3. Junctional dilatation at PCoA
origin ( infundibuli ) 6 %
4. PCoA duplication/ fenestraion
– rare
PCoA fenestration
PCoA hypoplasia

70. • PCoM is larger than P1 segment of PCA
and supplies the bulk of PCA . PCA
therefore is a part of anterior circulation
• Non fetal PCA , PCoM lies superomedial
to CN3
• Fetal PCA, PCoM lies superior lateral
to CN 3
•Hypoplastic /
absent P1 segment
•PCoA is same
diameter as I/L
PCA

71. •Infundibular dilatation of
PCoA at origin from ICA- 5-
15%
•Should be 2 mm or less
•Funnel shaped , conical
•PCoA arises from apex

72. Within suprasellar cistern under optic tract
Posteromedially around temporal lobe uncus
Cisternal Course :
Intraventricular course:
AChA angles sharply laterally
Enters choroidal fissure of temporal bone
Abrupt kink – plexal point
AChA-origin few mms above PCoA
Cisternal segment
Intraventricular segment

73. Supplies
Choroidal plexus of lateral ventricle (
temporal horn and atrium )
Optic tract and cerebral peduncle
Uncal and parahippocampal gyri of
temporal lobe .
Thalamus and posterior limb of
internal capsule.
Anastamoses – with AChA segments
and LPChA and MPChA
Variants – uncommon
Aplasia rare
Hypoplasia – 3 %
Hyperplasia – 2.3 %
AP mid arterial DSA
AP Late arterial DSAMRA lateral view
Choriodal
blush

74. Terminal ICA
Anterior cerebral artery Middle cerebral artery
3D CTA
MCA
ACA
ICA
3D CTAMid arterial phase DSA

75. 2ICAs
Horizontal segment
A1 of both ACAs
2 Posterior
communicating
arteries
Anterior
communicating artery
Horizontal segment
P1 of both PCA s
Basilar artery

76. Interconnected arterial
polygon
Location – surrounds
ventral surface of
diencephalon,
adjacent to optic nerve
and tracts, inferolateral
to hypothalamus
Anterior
circulation
2 B/L ICAs
2ACAs
Unpaired ACoA
anteriorly
Posterior
circulation
Basilar bifurcation
from merged VAs
2PCAs from
BAs
B/L PCoAs

77. 3DVRT CTA MRA
CT MRA
1. A1
2. P1
3. PCoA
4. ACoA

78. Cerebral
angiography-
single injection
Contrast
enhanced CT –
maximum
intensity
projection
Invasive MRA- time of
flight sequence
with multiple
overlapping thin
slab technique
Transcranial
Doppler
ultrasound
Non
invasive

79. • Medial lenticulostriate arteries
• Recurrent artery of HeubnerACAs
• Perforating branches – hypothalamus , optic
chiasma , cingulate gyrus , corpus callosum ,
fornix
• Large vessel – median artery of corpus callosum
arises from ACoA
ACoA
• Anterior thalamoperforating arteriesPCoA
• Posterior thalamoperforating arteries
• Thalamogeniculate arteries
Basilar artery,
PCAs
Supplies-
1.Optic
chiasma
and tracts
2.Infundibulu
m
3.Hypothala
mus
4.Base of
brain

80.  Complete COW –only 20
– 25%
 Posterior circle
anomalies – 50%
anatomy specimens
Common variants
•Hypoplasia of 1 or both
PCoA – 34%
•Fetal origin of PCA from
ICA

81. •Hypoplasia or absent A1
ACA segment.
•Absent , duplicate or
multichannel ACoA – 10-15%

82. •Rare – congenital absence of 1 or
both ICAs
•Common – if 1 ICA absent
intrasellar intercommunicating
arteries
•ICA agenesis – intracranial
aneurysm common
•ACA- ACoA complex
•Infraoptic origin of ACA
•Single (azygous) ACA
(holoprosencephalies )
•PCoA- PCA- BA complex
•Persistent carotid basilar
anastomosis
Absent ICA

83.  ICAs develop from 3rd aortic arches ,
dorsal aortae
 Embryonic ICAs divide into cranial,caudal
 Cranial divisions –
▪ primitive olfactory , anterior / middle cerebral , anterior choroidal
arteries
▪ Anterior communicating artery – forms from coalescence of a midline
plexiform network ,it connects developing ACAs
 Caudal divisions –
▪ becomes posterior communicating arteries
▪ Supply stems of posterior cerebral arteries.
 Paired dorsal longitudinal neural arteries fuse – basilar artery
 Developing vertebrobasilar circulation usually incorporates PCAs
 Caudal ICA divisions regress forming PCoAs.

84.  Represent persistent embryonic
circulatory patterns
 Channels between embryonic aorta
(caudal carotid artery) and paired
longitudinal neural arteries (form
basilar and vertebral arteries ) fail to
regress.
1. Primitive persistent trigeminal artery
2. Primitive hypoglossal artery
3. Persistent otic artery
4. Proatlantal intersegmental artery
PCoA
PTA
Otic
Hypoglossal
Proatlantal
intersegmental

85. •Most common carotid vertebro basilar anastomoses - 0.1- 0.6%
•In utero – embryonic trigeminal artery supplies basilar artery before the PCoA and
vertebral artery develops
•As these vessels enlarge – PTA normally disappears
course – arise when ICA exists carotid canal and
enters cavernous sinus
Runs posterolaterally along trigeminal nerve 41%
Crosses over / throu dorsum sella before
joining basilar artery
Connects ICA to vertebrobasilar system trident shape on lateral DSA

86. •PCoA is absent
•Supply entire vertebrobasilar circulation distal to
anastomosis
Saltzmann type
Ι
• Fetal PCA and I/L P1 segment absent
• Fill superior cerebral arteries (SCA) with posterior
cerebral arteries (PCA ) fills via patent PCoA
Saltzmann type
ΙΙ
•Increased incidence of intracranial aneurysms / malformations
•Increased importance in transpenoidal surgery
Hypoplastic basilar

87.  2nd most common- 0.027-
0.26%
 .
 Intracranial aneurysms
 If present – single artery
that supplies brain stem
and cerebellum
Courses thro hypoglossal canal
Parallel to CN 12
Connects cervical ICA with
basilar artery

88. Red – PHA Blue – sigmoid sinus Pink – coil mass with basilar
tip aneurysm

89.  Origin – petrous ICA
 Course – medially thro internal
auditory meatus and joins caudal
basilar artery
 VA – hypoplastic / absent – POA is
the sole arterial supply to basilar
artery
Basilar artery
POA

90. •Proatlantal infact is occipital artery
•C1 segment connection is proatlantal
type 1
•C2 connection is proatlantal type 2
• vertebral artery proximal to proatlantal
is hypoplastic

91. ICA
Proatlantal
intersergmental
PIA – suboccipital anastamosis between ECA / cervical ICA and vertebral artery
– typically courses between the arch of C1 and occiput