radiologocal anatomy of the brain

2. IMAGING OF THEIMAGING OF THE
BRAINBRAIN

3. BRAINBRAIN
ANATOMY
IMAGING
MODALITIES

4. ANATOMYANATOMY
(DEVELOPMENT)(DEVELOPMENT)
 The beginning is the union of aThe beginning is the union of a
sperm with an ovum to form thesperm with an ovum to form the
zygotezygote..
 Then this single celled zygoteThen this single celled zygote
divides to become the multicellulardivides to become the multicellular
embryonic plate.embryonic plate.
 The cells of this plate are organizedThe cells of this plate are organized
into 3 layers: ectoderm, endoderm &into 3 layers: ectoderm, endoderm &
an intervening mesoderm.an intervening mesoderm.
 Thickening in the middle of theThickening in the middle of the
ectoderm forms the neural plate,ectoderm forms the neural plate,
folding of the neural plate forms thefolding of the neural plate forms the
neural tube.neural tube.
 The cranial part of the neural tubeThe cranial part of the neural tube
becomes the brain while the caudalbecomes the brain while the caudal
part becomes the spinal cord.part becomes the spinal cord.

5.  The cranial part of the neural tube dilates into 3 primary vesicles : the forebrainThe cranial part of the neural tube dilates into 3 primary vesicles : the forebrain
(prosencephalon) , the midbrain (mesencephalon) & the hindbrain (rhombencephalon).(prosencephalon) , the midbrain (mesencephalon) & the hindbrain (rhombencephalon).
 From these 3 vesicles, 5 secondary vesicles develop.From these 3 vesicles, 5 secondary vesicles develop.

6.  Adult brain is formed of:Adult brain is formed of:
1- Cerebral hemispheres.1- Cerebral hemispheres.
2- Brain stem.2- Brain stem.
3- Cerebellum.3- Cerebellum.
All are covered with meninges, floating in a fluid (CSF) & enclosingAll are covered with meninges, floating in a fluid (CSF) & enclosing
a cavity ( ventricular system).a cavity ( ventricular system).

7.  Brain is contained in a bony box called: neurocranium.Brain is contained in a bony box called: neurocranium.

8. Cerebral hemispheresCerebral hemispheres
♥♥ The brain is formed of 2 cerebralThe brain is formed of 2 cerebral
hemispheres Right & Left separatedhemispheres Right & Left separated
by the interhemispheric fissure, butby the interhemispheric fissure, but
again connected to each otheragain connected to each other
throughthrough commissures:commissures:
1- Corpus callosum (rostrum,1- Corpus callosum (rostrum,
genu, body & splenium).genu, body & splenium).
2- Anterior commissure.2- Anterior commissure.
3- Posterior commissure.3- Posterior commissure.
4- Hippocampal commissure.4- Hippocampal commissure.
♥♥ Each hemisphere is formed of an outerEach hemisphere is formed of an outer
layer of grey matter (cerebral cortex)layer of grey matter (cerebral cortex)
which is formed of prominentwhich is formed of prominent gyri &&
interveningintervening sulci, and an inner layer, and an inner layer
of white matter ( centrum semiovaleof white matter ( centrum semiovale
& internal capsule).& internal capsule).
♥♥ Islands of grey matter are present insideIslands of grey matter are present inside
the white matter: basal gangliathe white matter: basal ganglia
(caudate, putamen & globus pallidus).(caudate, putamen & globus pallidus).

9. BASAL GANGLIABASAL GANGLIA
♣♣ Islands of neural cell bodies (grey matter)Islands of neural cell bodies (grey matter)
within the white matter.within the white matter.
♣♣ Formed of:Formed of:
1- Caudate nucleus (head, body & tail).1- Caudate nucleus (head, body & tail).
2- Putamen.2- Putamen.
3- Globus pallidus.3- Globus pallidus.
4- Amygdaloid nuclear complex (amygdala).4- Amygdaloid nuclear complex (amygdala).
5- Claustrum.5- Claustrum.
Globus pallidus + Putamen = LentiformGlobus pallidus + Putamen = Lentiform
nucleus.nucleus.
Caudate + Putamen = Striatum.Caudate + Putamen = Striatum.

11.  Certain sulci divide each hemisphere into lobes:Certain sulci divide each hemisphere into lobes:
1- The central sulcus separates the frontal (anteriorly) and the parietal1- The central sulcus separates the frontal (anteriorly) and the parietal
(posteriorly) lobes.(posteriorly) lobes.
2- The lateral sulcus (Sylvian fissure) separates the frontal & parietal lobes2- The lateral sulcus (Sylvian fissure) separates the frontal & parietal lobes
superiorly from the temporal lobe inferiorly.superiorly from the temporal lobe inferiorly.
3- The parieto-occipital sulcus marks the posterior boundary of the parietal3- The parieto-occipital sulcus marks the posterior boundary of the parietal
lobe & the anterior boundary of the occipital lobe.lobe & the anterior boundary of the occipital lobe.
♥♥ The insular lobe is buried within the lateral sulcus under operculaThe insular lobe is buried within the lateral sulcus under opercula
from the frontal, parietal & temporal lobes.from the frontal, parietal & temporal lobes.
♥♥ the limbic lobe is a C-shaped structure that lies along & above thethe limbic lobe is a C-shaped structure that lies along & above the
corpus callosum on the medial surface of the cerebral hemisphere.corpus callosum on the medial surface of the cerebral hemisphere.
 The cavity within the cerebral hemisphere isThe cavity within the cerebral hemisphere is the lateral ventriclethe lateral ventricle..

14.  THE DIENCEPHALON is a part of the brain that is distinct embryologicallyTHE DIENCEPHALON is a part of the brain that is distinct embryologically
however not separable anatomically from telencephalon (cerebral hemispheres).however not separable anatomically from telencephalon (cerebral hemispheres).
 It is formed of: thalamus, epithalamus, hypothalamus & subthalamus.It is formed of: thalamus, epithalamus, hypothalamus & subthalamus.
 The cavity within the diencephalon is the third ventricle.The cavity within the diencephalon is the third ventricle.

15. CerebellumCerebellum
 A small structure growing out from the posterior aspect of the brain & occupies theA small structure growing out from the posterior aspect of the brain & occupies the
posterior cranial fossa.posterior cranial fossa.
 It is formed of 2 cerebellar hemispheres connected in the midline byIt is formed of 2 cerebellar hemispheres connected in the midline by the vermis.the vermis.
 It forms the roof of the forth ventricle and connected to the brain stem by 3 cerebellarIt forms the roof of the forth ventricle and connected to the brain stem by 3 cerebellar
peduncles (superior, middle & inferior).peduncles (superior, middle & inferior).
 It is roofed by the tentorium cerebelli while a small dural reflection invests the grooveIt is roofed by the tentorium cerebelli while a small dural reflection invests the groove
between its hemispheres called falx cerebelli.between its hemispheres called falx cerebelli.
 The narrowest subdivisions of the cerebellar cortex are calledThe narrowest subdivisions of the cerebellar cortex are called foliafolia..

16.  Parts of the cerebellum:Parts of the cerebellum:
2 hemispheres & a vermis.2 hemispheres & a vermis.
Hemisphere:Hemisphere:
1- Anterior lobe: anterior to the primary fissure.1- Anterior lobe: anterior to the primary fissure.
2- Posterior lobe: between the primary fissure & postero-lateral2- Posterior lobe: between the primary fissure & postero-lateral
fissure.fissure.
3- Flocconodular lobe.3- Flocconodular lobe.

17. Brain stemBrain stem
 Connects the cerebral hemispheres & cerebellum to the spinal cord.Connects the cerebral hemispheres & cerebellum to the spinal cord.
 It is formed of:It is formed of:
1-Midbrin.1-Midbrin.
2-Pons.2-Pons.
3-Medulla oblongata.3-Medulla oblongata.

18. Ventral surfaceVentral surface::
MIDBRAINMIDBRAIN
-- 2 cerebral peduncle.2 cerebral peduncle.
- interpeduncular fossa.- interpeduncular fossa.
♥♥ The posterior perforated substance lies in theThe posterior perforated substance lies in the
interpeduncular fossa, it is penetrated byinterpeduncular fossa, it is penetrated by
branches of the posterior cerebral & posteriorbranches of the posterior cerebral & posterior
communicating arteries.communicating arteries.
♥♥ Oculomotor nerve CN III emerges from theOculomotor nerve CN III emerges from the
ventral surface.ventral surface.
PONSPONS
The superior pontine sulcus separates pons fromThe superior pontine sulcus separates pons from
midbrain, while the inferior pontine sulcusmidbrain, while the inferior pontine sulcus
separates it from medulla oblongata.separates it from medulla oblongata.
Base of the pons.Base of the pons.
Cranial nerves that emerge from its ventralCranial nerves that emerge from its ventral
surface are:surface are:
1- Trigeminal nerve CN V.1- Trigeminal nerve CN V.
2- Abducent nerve CN VI.2- Abducent nerve CN VI.
3- Facial nerve CN VII.3- Facial nerve CN VII.
4- Vestibulocochlear nerve CN VIII.4- Vestibulocochlear nerve CN VIII.
MEDULLA OBLONGATAMEDULLA OBLONGATA
Pyramids.Pyramids.
Olives.Olives.
Cranial nerves:Cranial nerves:
1- Glossopharyngeal nerve CN IX.1- Glossopharyngeal nerve CN IX.
2- Vagal nerve CN X.2- Vagal nerve CN X.
3- Accessory nerve CN XI.3- Accessory nerve CN XI.
4- Hypoglossal nerve CN XII.4- Hypoglossal nerve CN XII.

19. Dorsal surface:Dorsal surface:
MIDBRAINMIDBRAIN
- Superior colliculus.- Superior colliculus.
- Brachium of the superior colliculus.- Brachium of the superior colliculus.
- Inferior colliculus.- Inferior colliculus.
- Brachium of the inferior colliculus.- Brachium of the inferior colliculus.
superior & inferior colliculi form the quadrigeminalsuperior & inferior colliculi form the quadrigeminal
plate.plate.
*The trochlear nerve CN IV emerges from the*The trochlear nerve CN IV emerges from the
dorsal surface.dorsal surface.
PONSPONS
Upper part of rhomboid fossa:Upper part of rhomboid fossa:
- Median eminence.- Median eminence.
- Facial colliculus.- Facial colliculus.
- Sulcus limitans.- Sulcus limitans.
-Vestibular area.-Vestibular area.
-- Striae medullais.Striae medullais.
MEDULLA OBLONGATAMEDULLA OBLONGATA
Lower part of the rhomboid fossa:Lower part of the rhomboid fossa:
- Vagal trigone.- Vagal trigone.
- Hypoglossal trigone.- Hypoglossal trigone.
- Sulcus limitans.- Sulcus limitans.

21. VENTRICULARVENTRICULAR
SYSTEMSYSTEMVentricular system of the brain is actually a continuousVentricular system of the brain is actually a continuous
tube that is dilated in some parts to form ventricles.tube that is dilated in some parts to form ventricles.
It originates from the cavity of the neural tube.It originates from the cavity of the neural tube.
Components:Components:
●● 2 lateral ventricles → inside cerebral hemispheres.2 lateral ventricles → inside cerebral hemispheres.
●● third ventricle → inside diencephalon.third ventricle → inside diencephalon.
●● aqueduct of Sylvius → inside brain stem.aqueduct of Sylvius → inside brain stem.
it connects the third to the fourth ventricles.it connects the third to the fourth ventricles.
●● fourth ventricle → inside pons & medulla oblongata.fourth ventricle → inside pons & medulla oblongata.
Foramina:Foramina:
Some foramina connect ventricles to each other, these are:Some foramina connect ventricles to each other, these are:
2 foramina of Monro between lateral & third ventricle.2 foramina of Monro between lateral & third ventricle.
2 lateral foramina of Luschka & 1 median foramen of2 lateral foramina of Luschka & 1 median foramen of
Magendie.Magendie.
Choroid plexus:Choroid plexus:
a network of blood vessels that produce CSF.a network of blood vessels that produce CSF.

22.  Lateral ventricles:Lateral ventricles:
▪▪ 2 cavities each lies inside a cerebral2 cavities each lies inside a cerebral
hemisphere separated from each other byhemisphere separated from each other by
septum pellucidumseptum pellucidum
▪▪ A lateral ventricle is formed ofA lateral ventricle is formed of
--frontal hornfrontal horn in the frontal lobe.in the frontal lobe.
--bodybody in the parietal lobe.in the parietal lobe.
--posterior hornposterior horn in the occipitalin the occipital
lobelobe
--temporal horntemporal horn in the temporalin the temporal
lobe.lobe.
……..all meeting in a confluence..all meeting in a confluence
calledcalled trigone (atrium)trigone (atrium) whichwhich
contains the glomus that is a tuftcontains the glomus that is a tuft
of choroid plexus calcified & seenof choroid plexus calcified & seen
in CT.in CT.
▪▪ Lateral ventricleLateral ventricle is related anteriorly tois related anteriorly to
the genu of corpus callosum, superiorly tothe genu of corpus callosum, superiorly to
the body of corpus callosum, inferiorly tothe body of corpus callosum, inferiorly to
the third ventricle in midline & infero-the third ventricle in midline & infero-
laterally to the caudate nucleus &laterally to the caudate nucleus &
thalami.thalami.
▪▪ Its posterior horn lies within the occipitalIts posterior horn lies within the occipital
lobe, while its temporal horn extends intolobe, while its temporal horn extends into
the temporal horn with the hippocampusthe temporal horn with the hippocampus
lying on medial to it.lying on medial to it.

23.  Third ventricle:Third ventricle:
▪▪ Single midline structure that lies inbetweenSingle midline structure that lies inbetween
diencephalon structures ( thalamus &diencephalon structures ( thalamus &
hypothalamus).hypothalamus).
▪▪ It has 4 recesses:It has 4 recesses:
- preoptic & infundibular recesses- preoptic & infundibular recesses
anteriorly.anteriorly.
-suprapineal & pineal recesses-suprapineal & pineal recesses
posteriorly.posteriorly.
It is related superiorly to the fornix & inferiorly to:It is related superiorly to the fornix & inferiorly to:
anterior commissure, optic chiasm, infundibulum of the pituitary gland, clivus,anterior commissure, optic chiasm, infundibulum of the pituitary gland, clivus,
midbrain & posterior commissure….while posteriorly it is related to the pineal body &midbrain & posterior commissure….while posteriorly it is related to the pineal body &
splenium of corpus callosum.splenium of corpus callosum.

24.  Fourth ventricle:Fourth ventricle:
▪▪ Roofed by the cerebellum posteriorly whileRoofed by the cerebellum posteriorly while
pons & upper part of medulla oblongatapons & upper part of medulla oblongata
form the floor (rhomboid fossa).form the floor (rhomboid fossa).
▪▪ It has 2 lateral recesses.It has 2 lateral recesses.
▪▪ It opens inferiorly into the central canal ofIt opens inferiorly into the central canal of
the spinal cord.the spinal cord.

25. CAVUM VARIANTS:CAVUM VARIANTS:
 Cavum septum pellucidum:Cavum septum pellucidum:
•• Separates frontal horns of lateral ventriclesSeparates frontal horns of lateral ventricles
(anterior(anterior toto foramen of Monro)foramen of Monro)
•• 80% of term infants; 15% of adults80% of term infants; 15% of adults
•• May dilate; rare cause of obstructiveMay dilate; rare cause of obstructive
hydrocephalus.hydrocephalus.
 Cavum vergae:Cavum vergae:
•• Posterior continuation of cavum septumPosterior continuation of cavum septum
pellucidum; never exists without cavumpellucidum; never exists without cavum
septum pellucidum.septum pellucidum.
•• 30% of term infants; 15% of adults.30% of term infants; 15% of adults.
 Cavum velum interpositum:Cavum velum interpositum:
•• Extension of quadrigeminal plate cistern toExtension of quadrigeminal plate cistern to
foramenforamen ofof MonroMonro

26. CSF circulationCSF circulation
Formation:Formation:
--It is formed by choroid plexus that areIt is formed by choroid plexus that are
specialized cells covering blood vesselsspecialized cells covering blood vessels
present in the lateral ventricle (bodypresent in the lateral ventricle (body
temporal horn & trigone), third ventricletemporal horn & trigone), third ventricle
& fourth ventricle.& fourth ventricle.
--Blood supply to choroid plexus comes fromBlood supply to choroid plexus comes from
anterior choroidal artery (branch of theanterior choroidal artery (branch of the
internal carotid artery) & posteriorinternal carotid artery) & posterior
choroidal artery ( branch of thechoroidal artery ( branch of the
posterior cerebral artery).posterior cerebral artery).
Circulation:Circulation:
-CSF formed in the lateral ventricle flows-CSF formed in the lateral ventricle flows
to the third ventricle through the 2to the third ventricle through the 2
foramina of Monro then down theforamina of Monro then down the
aqueduct of Sylvius to the fourthaqueduct of Sylvius to the fourth
ventricle, from which it passes to theventricle, from which it passes to the
subarachnoid space ( cisterna magna)subarachnoid space ( cisterna magna)
via the median foramen of Magendie &via the median foramen of Magendie &
the 2 lateral foramina of Luschka.the 2 lateral foramina of Luschka.

28. Absorption:Absorption:
--Wide spread absorption occur throughWide spread absorption occur through
walls of dural venous sinuses, but siteswalls of dural venous sinuses, but sites
of greatest absorption are at theof greatest absorption are at the
arachnoid villi especially in superiorarachnoid villi especially in superior
sagittal sinus.sagittal sinus.
CSF:CSF:
500 ml. are produced per day.500 ml. are produced per day.
140 ml. total volume.140 ml. total volume.
80-180 mm. water normal pressure from80-180 mm. water normal pressure from
lumbar puncture for a patient in laterallumbar puncture for a patient in lateral
decubitusdecubitus

29. Meninges & CSF spacesMeninges & CSF spaces
 Meninges are the membranes that cover the surface of the brain.Meninges are the membranes that cover the surface of the brain.
 They are 3 in number named: -dura mater.They are 3 in number named: -dura mater.
-arachnoid mater.-arachnoid mater.
-pia mater.-pia mater.

30. Dura mater:Dura mater:
☺☺ The outermost layer.The outermost layer.
☺☺ It covers the brain & spinal cord, however it doesn’t dip into sulci.It covers the brain & spinal cord, however it doesn’t dip into sulci.
☺☺ It ends caudally at the level ofIt ends caudally at the level of the second sacral vertebrathe second sacral vertebra as a thin fibrous bandas a thin fibrous band
(filum terminale) that continues down to fuse with the coccyx.(filum terminale) that continues down to fuse with the coccyx.
☺☺ Dura mater is a tough fibrous layer formed by fusion of:Dura mater is a tough fibrous layer formed by fusion of:
1- an inner dura mater proper.1- an inner dura mater proper.
2- the periostium of skull bones that is attached to suture lines.2- the periostium of skull bones that is attached to suture lines.
…….these 2 layers are tightly fused together except when they split to enclose.these 2 layers are tightly fused together except when they split to enclose
dural sinuses.dural sinuses.
☺☺ Superficial to dura mater is a potential space called extra-dural space, this space isSuperficial to dura mater is a potential space called extra-dural space, this space is
limited at suture lines.limited at suture lines.
☺☺ Deep to the dura another potential space; the sub-dural space, it lies between dura &Deep to the dura another potential space; the sub-dural space, it lies between dura &
arachnoid mater.arachnoid mater.

31.  Dural folds:Dural folds:
♣♣ Falx cerebri:Falx cerebri:
- It is formed when the 2 dural layers split to enclose the superior sagittal sinus, occupying the- It is formed when the 2 dural layers split to enclose the superior sagittal sinus, occupying the
interhemispheric fissure, extending from crista galli anteriorly till attachment to theinterhemispheric fissure, extending from crista galli anteriorly till attachment to the
superior surface of tentorium cerebelli (another dural fold) posteriorly.superior surface of tentorium cerebelli (another dural fold) posteriorly.
- Its upper edge is attached to the skull, containing the superior sagittal sinus, while its lower edge is- Its upper edge is attached to the skull, containing the superior sagittal sinus, while its lower edge is
the free edge and it encloses the inferior sagittal sinus…..the straight sinus runs along the line ofthe free edge and it encloses the inferior sagittal sinus…..the straight sinus runs along the line of
attachment of falx cerebri to tentorium cerebelli.attachment of falx cerebri to tentorium cerebelli.
- The point where the 2 dural folds meet against the internal occipital protuberance is the site of- The point where the 2 dural folds meet against the internal occipital protuberance is the site of
confluence of dural venous sinuses.confluence of dural venous sinuses.

32. ♣♣ Tentorium cerebelli:Tentorium cerebelli:
- A horizontally placed dural fold that- A horizontally placed dural fold that
separates cerebral hemispheres superiorlyseparates cerebral hemispheres superiorly
from cerebellum inferiorly.from cerebellum inferiorly.
- Its postero-lateral edge is attached to the- Its postero-lateral edge is attached to the
skull bones at the boundaries of theskull bones at the boundaries of the
posterior cranial fossa & anteriorly to theposterior cranial fossa & anteriorly to the
posterior clinoid processes, enclosing theposterior clinoid processes, enclosing the
transverse sinuses & forms the lateraltransverse sinuses & forms the lateral
wall of the cavernous sinus.wall of the cavernous sinus.
- Its anterior edge is a free edge that- Its anterior edge is a free edge that
encircles the brain stem (at the tentorialencircles the brain stem (at the tentorial
notch) and extends anteriorly to attach tonotch) and extends anteriorly to attach to
the anterior clinoid processes & forms thethe anterior clinoid processes & forms the
roof of the cavernous sinus.roof of the cavernous sinus.
♣♣ Diaphragma sellae:Diaphragma sellae:
- A dural fold that is stretched between the- A dural fold that is stretched between the
anterior & posterior clinoid processes.anterior & posterior clinoid processes.
- It roofs the sella turcica & is pierced by the- It roofs the sella turcica & is pierced by the
infundibulum of pituitary gland.infundibulum of pituitary gland.
♣♣ Falx cerebelli:Falx cerebelli:
- A small dural fold attached to the internal- A small dural fold attached to the internal
occipital crest & projects between the 2occipital crest & projects between the 2
cerebellar hemispheres.cerebellar hemispheres.

33.  Arachnoid mater:Arachnoid mater:
---- A delicate connective tissue that lies between dura & pia mater.A delicate connective tissue that lies between dura & pia mater.
the space between arachnoid & pia mater is the subarachnoid space through which thin trabeculaethe space between arachnoid & pia mater is the subarachnoid space through which thin trabeculae
extend the 2 meningeal layers & it is the space within which CSF flows around brain.extend the 2 meningeal layers & it is the space within which CSF flows around brain.
- At some parts this space widens to form the subarachnoid spaces:- At some parts this space widens to form the subarachnoid spaces:
1- cisterna magna.1- cisterna magna.
2- cisterna pontis (basilar artery).2- cisterna pontis (basilar artery).
3- cisterna interpeduncularis (trochlear nerve).3- cisterna interpeduncularis (trochlear nerve).
4- supra-sellar cistern (optic chiasm).4- supra-sellar cistern (optic chiasm).
5- pericallosal cistern.5- pericallosal cistern.
6- quadrigeminal cistern.6- quadrigeminal cistern.
7- ambient cistern.7- ambient cistern.
8- cistern of lateral fissure.8- cistern of lateral fissure.

34.  Pia mater:Pia mater:
- A vascular layer intimately- A vascular layer intimately
related to brain surface andrelated to brain surface and
even invests into the sulci.even invests into the sulci.
- Carries blood vessels to brain.- Carries blood vessels to brain.

35. Pituitary glandPituitary gland
 A small endocrinal gland that projects down from the inferior surface of theA small endocrinal gland that projects down from the inferior surface of the
brain to lie in sella turcica.brain to lie in sella turcica.
 It connected to the brain by the infundibulum.It connected to the brain by the infundibulum.
 It lies above the body of sphenoid bone (with sphenoid air sinus), belowIt lies above the body of sphenoid bone (with sphenoid air sinus), below
diaphragma sellae & inbetween the 2 cavernous sinuses.diaphragma sellae & inbetween the 2 cavernous sinuses.
 Optic chiasm is closely related to the gland lying antero-superior to it.Optic chiasm is closely related to the gland lying antero-superior to it.

36. Blood vesselsBlood vessels
 Arteries:Arteries:
1- Carotid system.1- Carotid system.
2- Vertebro-basilar system.2- Vertebro-basilar system.
 Veins:Veins:
1- Cerebral veins.1- Cerebral veins.
2- Dural venous sinuses.2- Dural venous sinuses.

37.  ArteriesArteries
Carotid system:Carotid system:
-Formed of the internal carotid artery, it rises from the common carotid artery in the neck at the level of C6.-Formed of the internal carotid artery, it rises from the common carotid artery in the neck at the level of C6.
-It runs upward till skull base to pass through the carotid canal (of petrous bone).-It runs upward till skull base to pass through the carotid canal (of petrous bone).
-Then it curves forward & medially to emerge from foramen lacerum.-Then it curves forward & medially to emerge from foramen lacerum.
-Emerging out from this foramen it goes into the cavernous sinus running forward then upward again beside body-Emerging out from this foramen it goes into the cavernous sinus running forward then upward again beside body
of sphenoid bone.of sphenoid bone.
-It pierces the dura just lateral to the anterior clinoid process to run backward (carotid siphon) above the cavernous-It pierces the dura just lateral to the anterior clinoid process to run backward (carotid siphon) above the cavernous
sinus & below the optic nerve, then upward to divide into anterior & middle cerebral arteries below thesinus & below the optic nerve, then upward to divide into anterior & middle cerebral arteries below the
anterior perforated substance.anterior perforated substance.
-Parts of the internal carotid artery:-Parts of the internal carotid artery:
1- Cervical part.1- Cervical part.
2- Petrous part.2- Petrous part.
3- Cavernous part.3- Cavernous part.
4- Cerebral (supra-clinoid) part.4- Cerebral (supra-clinoid) part.

38.  Branches :Branches :
Cervical part no branchesCervical part no branches
Petrous par - carotico-tympanic.Petrous par - carotico-tympanic.
- pterygoid.- pterygoid.
Cavernous part - cavernousCavernous part - cavernous
- hypophyseal.- hypophyseal.
- meningeal.- meningeal.
Cerebral part - ophthalmic.Cerebral part - ophthalmic.
- anterior cerebral.- anterior cerebral.
- middle cerebral.- middle cerebral.
- posterior communicating.- posterior communicating.
- anterior choroidal.- anterior choroidal.
Ophthalmic artery gives: central artery of retina.Ophthalmic artery gives: central artery of retina.
lacrimal artery.lacrimal artery.
muscular branches.muscular branches.
ciliary arteries.ciliary arteries.
supra-orbital artery.supra-orbital artery.
supra-trochlear artery.supra-trochlear artery.
anterior ethmoidal artery.anterior ethmoidal artery.
posterior ethmoidal artery.posterior ethmoidal artery.
meningeal branch.meningeal branch.
medial palpebral arteries.medial palpebral arteries.
dorsal nasal artery.dorsal nasal artery.

39. Anterior cerebral artery:Anterior cerebral artery:
1- Central branches:1- Central branches:
These penetrate through the posterior penetrated substance to supply anterior parts ofThese penetrate through the posterior penetrated substance to supply anterior parts of
corpus callosum & basal ganglia.corpus callosum & basal ganglia.
2- Cortical branches.2- Cortical branches.
3- Anterior communicating artery.3- Anterior communicating artery.

40. Middle cerebral artery:Middle cerebral artery:
1- central branches:1- central branches:
they pass through the anterior perforated substance to supply basal ganglia, they are:they pass through the anterior perforated substance to supply basal ganglia, they are:
the lateral striate arteries, medial striate arteries & thalamo-striate artery (artery of cerebralthe lateral striate arteries, medial striate arteries & thalamo-striate artery (artery of cerebral
haemorrhage).haemorrhage).
2- cortical branches.2- cortical branches.

41.  Segments of the anterior cerebral artery:Segments of the anterior cerebral artery:
A1 segment:A1 segment: runs beneath the frontal lobe.runs beneath the frontal lobe.
A2 segment:A2 segment: runs upward around the genu of corpus callosum.runs upward around the genu of corpus callosum.
A3 segment:A3 segment: actually it is the 2 terminal branches of the anterior cerebral artery;actually it is the 2 terminal branches of the anterior cerebral artery;
callosomarginal & pericallosal arteries.callosomarginal & pericallosal arteries.
 Segments of the middle cerebral artery:Segments of the middle cerebral artery:
M1 segment ( the horizontal segment):M1 segment ( the horizontal segment): runs in the Sylvian fissure.runs in the Sylvian fissure.
M2 segment ( the insular segment):M2 segment ( the insular segment): this is formed of 2 or 3 branches of M1, theythis is formed of 2 or 3 branches of M1, they
run on the insula, they give multiple branchesrun on the insula, they give multiple branches
(M3).(M3).
M3 segment ( the opercular segment):M3 segment ( the opercular segment): run over the frontoparietal & temporalrun over the frontoparietal & temporal
opercula.opercula.
M4 segment (cortical branches):M4 segment (cortical branches): variable & complex, include temporal, ascendingvariable & complex, include temporal, ascending
frontoparietal, parietal, angular & posteriorfrontoparietal, parietal, angular & posterior
temporal branches.temporal branches.

42. Vertebro-basilar system:Vertebro-basilar system:
- Formed by 2 vertebral arteries (Rt & Lt) thatFormed by 2 vertebral arteries (Rt & Lt) that
arise fromarise from the subclavian arteries (1the subclavian arteries (1stst
part) atpart) at
the root of the neck.the root of the neck.
- Each vertebral artery passes through foraminaEach vertebral artery passes through foramina
of the transverse processes of the upperof the transverse processes of the upper
cervical vertebrae cervical vertebrae tillcervical vertebrae cervical vertebrae till
foramen magnum through which it entersforamen magnum through which it enters
cranial cavity.cranial cavity.
- It runs up on the ventral surface of brain stemIt runs up on the ventral surface of brain stem
to join its fellow at lower border of pons to formto join its fellow at lower border of pons to form
the basilar artery.the basilar artery.
- The basilar artery runs up till upper border ofThe basilar artery runs up till upper border of
pons where it divides into Rt. & Lt. posteriorpons where it divides into Rt. & Lt. posterior
cerebral arteries.cerebral arteries.
- Branches:Branches:
Vertebral arteryVertebral artery:- spinal branches.:- spinal branches.
- muscular branches.- muscular branches.
- meningeal branches.- meningeal branches.
- posterior spinal artery.- posterior spinal artery.
- anterior spinal artery.- anterior spinal artery.
- posterior inferior cerebellar artery.- posterior inferior cerebellar artery.
- medullary arteries.- medullary arteries.

43. Basilar artery:Basilar artery:- pontine branches.- pontine branches.
- labyrinthine artery.- labyrinthine artery.
- anterior inferior cerebellar artery.- anterior inferior cerebellar artery.
- superior cerebellar artery.- superior cerebellar artery.
Posterior cerebral artery:Posterior cerebral artery:
- central branches. - posterior choroidal arteries.- central branches. - posterior choroidal arteries.
- cortical branches.- cortical branches.

44.  Parts of posterior cerebral artery:Parts of posterior cerebral artery:
P1:P1: the segment before posterior communicating artery.the segment before posterior communicating artery.
P2 (ambient segment):P2 (ambient segment): runs in the ambient cistern.runs in the ambient cistern.
P3 (quadrigeminal segment):P3 (quadrigeminal segment): runs in quadrigeminal cistern.runs in quadrigeminal cistern.
P4:P4: the terminal portion of posterior cerebral artery that includes the occipital &the terminal portion of posterior cerebral artery that includes the occipital &
inferior temporal branches.inferior temporal branches.

45. Circle ofCircle of
Willis:Willis:
- This is an anastomotic circle formed by branches- This is an anastomotic circle formed by branches
of carotid & vertebro-basilar system.of carotid & vertebro-basilar system.
- It provides alternative sources of blood when- It provides alternative sources of blood when
there is deficiency in one of the arteriesthere is deficiency in one of the arteries
supplying the brain, however it can only servesupplying the brain, however it can only serve
this function with the gradually progressingthis function with the gradually progressing
deficiency not the sudden one.deficiency not the sudden one.

46. Circle of Willis is present inCircle of Willis is present in
the interpeduncular cistern,the interpeduncular cistern,
surrounding optic chiasm &surrounding optic chiasm &
infundibulum of pituitaryinfundibulum of pituitary
gland.gland.

47.  Cerebral veins :Cerebral veins :
1- Superficial veins:1- Superficial veins:
These are multiple veins that originate from subcortical medullary substance to run on theThese are multiple veins that originate from subcortical medullary substance to run on the
surface of the brain, then pass through subarachnoid space to penetrate arachnoid mater &surface of the brain, then pass through subarachnoid space to penetrate arachnoid mater &
drain into dural venous sinuses.drain into dural venous sinuses.
2- Deep veins:2- Deep veins:
These drain deep parts of the brain; septal area, thalamus, basal ganglia, …These drain deep parts of the brain; septal area, thalamus, basal ganglia, …
Include: - Saptal vein.Include: - Saptal vein.
- Thalamostriate vein.- Thalamostriate vein.
- Terminal vein.- Terminal vein.
- Great vein of Galen (drains into the straight sinus).- Great vein of Galen (drains into the straight sinus).

48.  Dural venous sinuses:Dural venous sinuses:
- Endothelium lined spaces created by splitting of dura mater at certain areas on inner surface- Endothelium lined spaces created by splitting of dura mater at certain areas on inner surface
of the skull.of the skull.
- All cerebral veins drain into them & they drain into the internal jugular veins.- All cerebral veins drain into them & they drain into the internal jugular veins.
- They include:- They include:
1- Superior sagittal sinus. 2- Inferior sagittal sinus.1- Superior sagittal sinus. 2- Inferior sagittal sinus.
3- Straight sinus. 4- Rt. & Lt. transverse sinuses.3- Straight sinus. 4- Rt. & Lt. transverse sinuses.
5- Sigmoid sinus. 6- Superior petrosal sinus.5- Sigmoid sinus. 6- Superior petrosal sinus.
7- Inferior petrosal sinus. 8- Cavernous sinus.7- Inferior petrosal sinus. 8- Cavernous sinus.

49. Cross sectionalCross sectional
anatomyanatomy

50. Imaging of theImaging of the
brainbrain

51. Imaging modalitiesImaging modalities
include:include:
1- CT.1- CT.
2- MRI.2- MRI.
3- Angiography.3- Angiography.
4- Radio-isotope scanning4- Radio-isotope scanning
(PET & SPECT).(PET & SPECT).
5- Ultrasound & Doppler.5- Ultrasound & Doppler.
6- Others: - plain X-ray.6- Others: - plain X-ray.
- cisternography.- cisternography.
- pneumography.- pneumography.
- thermography.- thermography.
- air meatography.- air meatography.

52. CT scanCT scan
 Godfrey Hounsfield a physist who,Godfrey Hounsfield a physist who,
together with Dr. James Ambrosetogether with Dr. James Ambrose
(a consultant radiologist)(a consultant radiologist)
developed the first CT scanner indeveloped the first CT scanner in
1971 in England1971 in England

53. ☺☺ The idea of Ct depends on receiving the x-rays coming out of theThe idea of Ct depends on receiving the x-rays coming out of the
patient by detectors (instead of a photosensitive film), these detectorspatient by detectors (instead of a photosensitive film), these detectors
transmit data to a computer that through a certain equation processestransmit data to a computer that through a certain equation processes
these data & introduces them as a cross sectional image.these data & introduces them as a cross sectional image.
☺☺ CT scanners have developed into different generations from the firstCT scanners have developed into different generations from the first
to the fourth generation according to shape of x-ray beam, number ofto the fourth generation according to shape of x-ray beam, number of
detectors & the relative movement of both to each other.detectors & the relative movement of both to each other.

55.  Indications of CT scanning ofIndications of CT scanning of
the brain:the brain:
these include suspected intra-these include suspected intra-
cranial lesions either traumatic (as extra-cranial lesions either traumatic (as extra-
or sub-dural haematoma, intra-cerebralor sub-dural haematoma, intra-cerebral
contusions,….) or non traumatic (ascontusions,….) or non traumatic (as
cerebral infarctions, intra-cerebralcerebral infarctions, intra-cerebral
haemorrhage, neoplasm, abscess,…..).haemorrhage, neoplasm, abscess,…..).
 Protocol:Protocol:
- scanning can be done in axial & coronal- scanning can be done in axial & coronal
planes according to site & nature ofplanes according to site & nature of
pathology.pathology.
- sagittal & a 3 dimensional images can- sagittal & a 3 dimensional images can
be obtained through reconstruction ofbe obtained through reconstruction of
data.data.
- the patient lies supine on couch then a- the patient lies supine on couch then a
lateral topogram is acquired (similar to alateral topogram is acquired (similar to a
plain x-ray skull lateral view) to have aplain x-ray skull lateral view) to have a
map of the area to be examined & planmap of the area to be examined & plan
the study.the study.
- the baseline plane is about 15 degrees- the baseline plane is about 15 degrees
to the orbito-meatal line.to the orbito-meatal line.
slice thickness:slice thickness:
5 mm. for the posterior fossa & 105 mm. for the posterior fossa & 10
mm. for the rest of the brain.mm. for the rest of the brain.
10 mm. all through the brain for10 mm. all through the brain for
emergencies.emergencies.

56. Use of a contrastUse of a contrast
medium:medium:
- cases of intra-cerebral- cases of intra-cerebral
haemorrhage, infarctions,haemorrhage, infarctions,
hydrocephalus & trauma usehydrocephalus & trauma use
of a contrast medium is notof a contrast medium is not
usually required.usually required.
- suspected cases of- suspected cases of
neoplasm, infective diseasesneoplasm, infective diseases
& vascular lesions, a pre- && vascular lesions, a pre- &
post-contrast study arepost-contrast study are
required to increaserequired to increase
diagnostic accuracy throughdiagnostic accuracy through
the pattern of enhancement ofthe pattern of enhancement of
these lesions.these lesions.
Contrast medium:Contrast medium:
urographin 50-100 ml.urographin 50-100 ml.
300-370 mgI/ml.300-370 mgI/ml.
HandHand injectioninjection

57. Radiographic anatomyRadiographic anatomy

58.  In some situations (as in the search ofIn some situations (as in the search of
pituitary gland pathology) coronal CTpituitary gland pathology) coronal CT
study is performed with thinner slicestudy is performed with thinner slice
thickness (3 mm.), the baseline then isthickness (3 mm.), the baseline then is
perpendicular to the hard palate with theperpendicular to the hard palate with the
patient lying in prone position.patient lying in prone position.
 For detection of bone pathology inFor detection of bone pathology in
association of brain pathology, boneassociation of brain pathology, bone
widow can display an adequate image ofwidow can display an adequate image of
bone & a high resolution can be done.bone & a high resolution can be done.

59.  Other CT techniques:Other CT techniques:
1- Perfusion computed tomography:1- Perfusion computed tomography:
- This is a CT study of regional blood flow to brain.- This is a CT study of regional blood flow to brain.
- It detects amount of blood flow to a specific area in cerebral blood vessel or brain- It detects amount of blood flow to a specific area in cerebral blood vessel or brain
parenchyma through detection of changes in Hounsfield units over time before &parenchyma through detection of changes in Hounsfield units over time before &
after injection of a contrast medium.after injection of a contrast medium.
2- Xenon computed tomography:2- Xenon computed tomography:
- This study relies on the fact that Xenon attenuates X-rays similar to iodine & the fact- This study relies on the fact that Xenon attenuates X-rays similar to iodine & the fact
that it can pass through blood-brain barrier.that it can pass through blood-brain barrier.
- Xenon is inhaled & at the same time CT study is performed recording changes in- Xenon is inhaled & at the same time CT study is performed recording changes in
Hounsfield units over time & translating them into a coloured map in which eachHounsfield units over time & translating them into a coloured map in which each
colour denotes a value for blood flow.colour denotes a value for blood flow.
These 2 studies are specifically helpful in cerebrovascular diseases especiallyThese 2 studies are specifically helpful in cerebrovascular diseases especially
early detection of strokes.early detection of strokes.
3- CT angiography.3- CT angiography.

60. M R IM R I
 The principle of MRI (MagneticThe principle of MRI (Magnetic
Resonance Imaging) comes from theResonance Imaging) comes from the
assumption that if an odd numberedassumption that if an odd numbered
nucleus is placed in a magnetic field itnucleus is placed in a magnetic field it
behaves as a small bar magnet, so if it isbehaves as a small bar magnet, so if it is
hit with radio-wave pulses (sequence)hit with radio-wave pulses (sequence)
with different time intervals (TR, TE/2 )with different time intervals (TR, TE/2 )
this nucleus sends back a signal that isthis nucleus sends back a signal that is
different according to the tissue.different according to the tissue.
 So, different signals of differentSo, different signals of different
intensities build up a contrast betweenintensities build up a contrast between
different tissues, as seen on an imagedifferent tissues, as seen on an image
 AcAcccoorrdidinngg toto tthehe ttiimmee iinntteervarvall bbeettwweeeenn
pulses, images acquired are called T1,pulses, images acquired are called T1,
T2, proton density,….T2, proton density,….

61. Standard protocol:Standard protocol:
- Different planes can be acquired (axial, sagittal &coronal) with the patient in supine position.- Different planes can be acquired (axial, sagittal &coronal) with the patient in supine position.
- Usually T2- weighted images are acquired first in coronal or axial planes, then T1-weighted- Usually T2- weighted images are acquired first in coronal or axial planes, then T1-weighted
images are taken pre-& post-contrast.images are taken pre-& post-contrast.
- Axial images are parallel to the hard palate & the coronal images are perpendicular to it.- Axial images are parallel to the hard palate & the coronal images are perpendicular to it.
Indications:Indications:
- Suspected parenchymal brain lesion as haemorrhage, tumours, multiple sclerosis,…- Suspected parenchymal brain lesion as haemorrhage, tumours, multiple sclerosis,…
- Suspected vascular brain lesion as aneurysm,…- Suspected vascular brain lesion as aneurysm,…
Contraindications:Contraindications:
- Presence of metallic object as ferromagnetic aneurysmal clips, pacemakers, suspected metallic- Presence of metallic object as ferromagnetic aneurysmal clips, pacemakers, suspected metallic
foreign body,…..foreign body,…..
- These objects may move, dislodge, heat up or dysfunction.- These objects may move, dislodge, heat up or dysfunction.
Contrast medium:Contrast medium:
- Gadolinium-DTPA- Gadolinium-DTPA
- 0.2 ml./kg. body weight- 0.2 ml./kg. body weight
- Hand injection- Hand injection

62. ♥♥♥♥ Proton density imageProton density image
fast spin echo sequencefast spin echo sequence
TR/TE =3000/20.TR/TE =3000/20.
♥♥♥♥T2 weighted imageT2 weighted image
fast spin echo sequencefast spin echo sequence
TR/TE =3000/90.TR/TE =3000/90.
♥♥♥♥ T1 weighted imageT1 weighted image
spin echo sequencespin echo sequence
TR/TE =400/14.TR/TE =400/14.

63. RADIOLOGICALRADIOLOGICAL
ANATOMYANATOMY

64. Other MRI techniques:Other MRI techniques:
1- MR diffusion imaging:1- MR diffusion imaging:
This technique depends on the constant random movement of water molecules acrossThis technique depends on the constant random movement of water molecules across
membranes, this movement depends on energy delivered by blood supply.membranes, this movement depends on energy delivered by blood supply.
So when blood supply to an area in the brain, movement slows or stops reflecting changes inSo when blood supply to an area in the brain, movement slows or stops reflecting changes in
the diffusion-weighted MRI image that uses certain sequence that records this movement.the diffusion-weighted MRI image that uses certain sequence that records this movement.
2- MR spectroscopy:2- MR spectroscopy:
Some substances in brain send characteristic signals on MRI.Some substances in brain send characteristic signals on MRI.
These substances are affected (and hence their signals) by certain diseases.These substances are affected (and hence their signals) by certain diseases.
3-Functional MRI:3-Functional MRI:
Detects changes in signal intensity at a specific region (region of interest) associated withDetects changes in signal intensity at a specific region (region of interest) associated with
activation of this region.activation of this region.
4- MR perfusion imaging.4- MR perfusion imaging.
5- MR angiography.5- MR angiography.

65. Which is better, CT OR MRI ?Which is better, CT OR MRI ?
 MRI is much more superior than CT if we are looking for a parenchymalMRI is much more superior than CT if we are looking for a parenchymal
lesion, MRI gives better definition & anatomy of the brain tissue. Alsolesion, MRI gives better definition & anatomy of the brain tissue. Also
it carries no hazards of ionizing radiation.it carries no hazards of ionizing radiation.
 However, if a bone lesion is suspected or being looked for, MRI wouldHowever, if a bone lesion is suspected or being looked for, MRI would
be useless & CT would be the method of choice.be useless & CT would be the method of choice.
 Also MRI takes so much time & is not suitable in some situations asAlso MRI takes so much time & is not suitable in some situations as
claustrophobic patients, patients with pacemakers or ferro-magneticclaustrophobic patients, patients with pacemakers or ferro-magnetic
objects.objects.

66. ANGIOGRAPHYANGIOGRAPHY
 Angiography is the opacification of blood vessels throughAngiography is the opacification of blood vessels through
the intra-venous injection of a contrast material.the intra-venous injection of a contrast material.
 It can be performed using:It can be performed using:
1- Conventional X-rays.1- Conventional X-rays.
2- CT angiography.2- CT angiography.
3- MR angiography.3- MR angiography.

67. Conventional angiographyConventional angiography
 Indications:Indications:
1- Investigations of cerebral aneurysms in cases of subarachnoid1- Investigations of cerebral aneurysms in cases of subarachnoid
haemorrhage.haemorrhage.
2- Investigation of AVM.2- Investigation of AVM.
3- Highly vascular tumours as a pre-operative assessment.3- Highly vascular tumours as a pre-operative assessment.
 Types:Types:
1- Carotid angiography.1- Carotid angiography.
2- Vertebral angiography.2- Vertebral angiography.
3- Dural sinuses venography.3- Dural sinuses venography.

68. Carotid angiography:Carotid angiography:
It studies the anterior circulation ( internal carotid artery)It studies the anterior circulation ( internal carotid artery)
Technique:Technique:
1- Direct puncture of the carotid artery at the level of cricoid cartilage.1- Direct puncture of the carotid artery at the level of cricoid cartilage.
2- Indirect; through femoral artery.2- Indirect; through femoral artery.
AArtery is punctured with a special needle, a guide wire is inserted then a catheter is placed along the guide wire.rtery is punctured with a special needle, a guide wire is inserted then a catheter is placed along the guide wire.
Catheter is pushed up to the aortic arch, swinged to lie against the opening of the common carotid ( orCatheter is pushed up to the aortic arch, swinged to lie against the opening of the common carotid ( or
brachiocephalic artery) & pushed up the common carotid then the internal carotid artery.brachiocephalic artery) & pushed up the common carotid then the internal carotid artery.
TTest injections are done frequently to guide the way up the arterial tree.est injections are done frequently to guide the way up the arterial tree.
Contrast medium is injected (6ml. hand injection).Contrast medium is injected (6ml. hand injection).
Images:Images:
Views: 1- Town’s view.Views: 1- Town’s view.
2- Lateral view.2- Lateral view.
3- anterior oblique view.3- anterior oblique view.
Image acquisition:Image acquisition:
2 images at 2 sec. run time.2 images at 2 sec. run time.
1 image at 6 sec. run time.1 image at 6 sec. run time.
for each view.for each view.

69. Radiological anatomy:Radiological anatomy:

71. Vertebral angiography:Vertebral angiography:
It studies the posterior circulation (the vertebro-basilar system).It studies the posterior circulation (the vertebro-basilar system).
Technique:Technique:
The same as carotid angiography, but catheter is passed through theThe same as carotid angiography, but catheter is passed through the
subclavian artery into the vertebral artery.subclavian artery into the vertebral artery.
Images are taken in Town’s view.Images are taken in Town’s view.
Lateral view.Lateral view.

74.  Dural sinusDural sinus
venography:venography:
It demonstrates the patency of dural sinuses.It demonstrates the patency of dural sinuses.
It is not a separate examination, it is actually the venousIt is not a separate examination, it is actually the venous
phase of arteriography.phase of arteriography.

75. CT angiographyCT angiography
With the introduction of spiral CT ( andWith the introduction of spiral CT ( and
more so with the multislice CT)more so with the multislice CT)
selective reconstruction of cerebralselective reconstruction of cerebral
blood vessels became possible.blood vessels became possible.
Images are acquired at slice collimation ofImages are acquired at slice collimation of
2 mm., table speed of 3 mm.,2 mm., table speed of 3 mm.,
reconstruction interval of 1 sec. &reconstruction interval of 1 sec. &
gantry rotation of .75 sec. injectinggantry rotation of .75 sec. injecting
120 ml of contrast at a rate of120 ml of contrast at a rate of
3ml/sec.3ml/sec.
Blood vessels can be displayed either asBlood vessels can be displayed either as
2D or 3D images.2D or 3D images.

77. MR angiographyMR angiography
 The basic idea behind it is simply that if we magnetize a specific sliceThe basic idea behind it is simply that if we magnetize a specific slice
including blood vessels within this slice & the blood cells inside the vessel,including blood vessels within this slice & the blood cells inside the vessel,
by time we record signals from this slice magnetized blood cells would haveby time we record signals from this slice magnetized blood cells would have
been moved along the vessel so we receive signals from thebeen moved along the vessel so we receive signals from the new cellsnew cells
TIME-OF-FLIGHT MRATIME-OF-FLIGHT MRA

78.  Another way of MRA acquisition is to receive signals from a sliceAnother way of MRA acquisition is to receive signals from a slice
then neutralize movement of blood in vessels.then neutralize movement of blood in vessels.
PHASE CONTRAST MRAPHASE CONTRAST MRA
 Also gadolinium can be injected to haveAlso gadolinium can be injected to have
CONTRAST ENHANCED MRACONTRAST ENHANCED MRA

79.  These changes in signals areThese changes in signals are
recorded, processed, reconstructedrecorded, processed, reconstructed
& displayed as 2D or 3D images.& displayed as 2D or 3D images.

80. SO……WHICH IS BETTER; COVENTIONAL,SO……WHICH IS BETTER; COVENTIONAL,
CTCT OROR MRIMRI ANGIOGRAPHY ?????ANGIOGRAPHY ?????
 Conventional angiography is the basic study of blood vessels offering anConventional angiography is the basic study of blood vessels offering an
excellent visualization of blood vessels & their pathology, however it isexcellent visualization of blood vessels & their pathology, however it is
an invasive examination with more hazards relative to CT &MRan invasive examination with more hazards relative to CT &MR
angiography.angiography.
 MRA is a non-invasive examination & offers good visualization ofMRA is a non-invasive examination & offers good visualization of
vessels, but it is time consuming, unsuitable for claustrophobic patientsvessels, but it is time consuming, unsuitable for claustrophobic patients
& turbulence in blood flow may affect signals.& turbulence in blood flow may affect signals.
 CT angiography is easier than conventional & MRA, needs less time,CT angiography is easier than conventional & MRA, needs less time,
suitable for claustrophobic patients & can produce 2D & 3D images (likesuitable for claustrophobic patients & can produce 2D & 3D images (like
MRA), however it doesn’t give the best resolution especially with theMRA), however it doesn’t give the best resolution especially with the
artifacts of calcium plaques which may be present at stenotic parts ofartifacts of calcium plaques which may be present at stenotic parts of
vessels.vessels.

82. ULTRASOUNDULTRASOUND
☼☼ Ultrasound waves are mechanical waves below the range audible by man.Ultrasound waves are mechanical waves below the range audible by man.
☼☼ These waves are generated by a piezo-electric material, reflect upon mediaThese waves are generated by a piezo-electric material, reflect upon media
interfaces & received by the piezo-electric material.interfaces & received by the piezo-electric material.
☼☼ Normally ultrasound waves are reflected by bone, so this modality cannot beNormally ultrasound waves are reflected by bone, so this modality cannot be
used for normal adult skull, however it is used for infants through patentused for normal adult skull, however it is used for infants through patent
fontanelles.fontanelles.
☼☼ Indications include: Congenital anomalies, hydrocephalus, intracranialIndications include: Congenital anomalies, hydrocephalus, intracranial
haemorrhage & intracranial cysts.haemorrhage & intracranial cysts.

83. ☻☻ Images are acquired inImages are acquired in
sagittal & coronal planessagittal & coronal planes
through the anterior fontanellethrough the anterior fontanelle
& in axial plane through the& in axial plane through the
antero-lateral fontanelle.antero-lateral fontanelle.
☻☻ A 5-7.5 MHz transducer isA 5-7.5 MHz transducer is
used.used.
☻☻ US offers a non-invasive,US offers a non-invasive,
cheap & portable method ofcheap & portable method of
brain imagingbrain imaging

85. DOPPLERDOPPLER
 Using the same principle of ultrasound, doppler detects & displays bloodUsing the same principle of ultrasound, doppler detects & displays blood
flow through the carotid vessels.flow through the carotid vessels.
 Recording waves from the common, external & internal carotid arteries isRecording waves from the common, external & internal carotid arteries is
performed with detection of stenosis & plaques.performed with detection of stenosis & plaques.
 This is especially important for cases of stoke & TIA.This is especially important for cases of stoke & TIA.
 CUS is a 2-step, or "duplex," procedure.CUS is a 2-step, or "duplex," procedure.

86. The 2 steps are asThe 2 steps are as
follows:follows:
1-Imaging:1-Imaging:
-Imaging is accomplished with the brightness-Imaging is accomplished with the brightness
mode (B-mode) technique.mode (B-mode) technique.
-The image usually is done in gray-scale, which-The image usually is done in gray-scale, which
is a brightness scale.is a brightness scale.
-Sometimes, color flow information is-Sometimes, color flow information is
superimposed on the gray-scale image. Bysuperimposed on the gray-scale image. By
convention, the color of the pulsating artery isconvention, the color of the pulsating artery is
red. This is called color Doppler imaging.red. This is called color Doppler imaging.
2-Spectral analysis:2-Spectral analysis:
-This allows measurement of blood flow-This allows measurement of blood flow
velocity.velocity.
-A probing cursor is placed in the artery (on the-A probing cursor is placed in the artery (on the
screen) and a signal intended to representscreen) and a signal intended to represent
blood flow velocity is generated.blood flow velocity is generated.
-The signal is both visual and auditory.-The signal is both visual and auditory.
-The signal has peaks and ebbs, which-The signal has peaks and ebbs, which
correspond to systolic and diastolic blood flow.correspond to systolic and diastolic blood flow.
The peaks and ebbs create the "spectrum."The peaks and ebbs create the "spectrum."

87. Vessel identification:Vessel identification:
 Identify common carotid artery:
-Pulsatile walls
-Smaller caliber than jugular vein
-Systolic peak and diastolic
endpoints in between that of
external and internal carotid
arteries on spectral analysis.

88.  Distinguishing internal and
external carotid arteries:
-ECA has smaller caliber.
-ICA is often posterolateral to ECA.
-ECA may have superior thyroid
artery branch coming off.
-ECA has virtually no diastolic flow
on
spectral analysis (i.e., high
resistance vessel).
-ECA shows positive "temporal tap"
(i.e., undulations in waveform with
tapping of temporal artery).
 Identifying vertebral artery:
-With probe parallel to carotid, angle
probe laterally and inferiorly.
-Look for vertebral body processes
that appear as hypoechoic
transverse bars.
-Vertebral artery runs perpendicular
to vertebral processes.

89. SSINGLEINGLE PPHOTONHOTON EEMISSIONMISSION
CCOMPUTEDOMPUTED TTOMOGRAPHYOMOGRAPHY
(SPECT)(SPECT)
This is a form of radio-isotope scanning where a radio-This is a form of radio-isotope scanning where a radio-
pharmaceutical is injected to flow with the cerebral blood flow,pharmaceutical is injected to flow with the cerebral blood flow,
emitting gamma rays that are detected with a gamma cameraemitting gamma rays that are detected with a gamma camera
& passed to a computer to process information & display it as& passed to a computer to process information & display it as
a coloured map.a coloured map.

90.  This technique can be used to study:This technique can be used to study:
-Cerebral blood flow.-Cerebral blood flow.
-Uptake by tumours.-Uptake by tumours.
 Examples of radiopharmaceuticalsExamples of radiopharmaceuticals
include:include:
133133
Xe,Xe, 123123
I isopropyle iodo-amphetamineI isopropyle iodo-amphetamine
(IMP) &(IMP) & 99m99m
Tc ethyl cycteinateTc ethyl cycteinate

91. PPOSITRONOSITRON
EEMISSIONMISSION
TTOMOGRAPHYOMOGRAPHY
(PET)(PET)
This is imaging through the injection of radiopharmaceuticalsThis is imaging through the injection of radiopharmaceuticals
that emit …….that emit …….
positronspositrons

92. WHAT ARE POSITRONSWHAT ARE POSITRONS
Positrons are positively chargedPositrons are positively charged
electrons, these combine with anelectrons, these combine with an
adjacent electron inadjacent electron in
anninhilation reaction leading toanninhilation reaction leading to
the emission of 2 high energythe emission of 2 high energy
gamma rays in oppositegamma rays in opposite
directions that are detected, theirdirections that are detected, their
position is calculated & a amp ofposition is calculated & a amp of
the radiopharmaceuticalthe radiopharmaceutical
distribution is put into a map.distribution is put into a map.

93.  PET imaging was based initially on thePET imaging was based initially on the
use labeled O2. This preference for theuse labeled O2. This preference for the
O2 was mainly due to the fact that theO2 was mainly due to the fact that the
main applications were related to themain applications were related to the
brain regional oxygen metabolism andbrain regional oxygen metabolism and
blood volume. Mid 70's theblood volume. Mid 70's the cyclotroncyclotron
enters the clinical world by makingenters the clinical world by making
available new isotopes such as 11C,available new isotopes such as 11C,
13N, 18F.13N, 18F.
 PET acceptance was boosted by thePET acceptance was boosted by the
development of 18F labeled 2-development of 18F labeled 2-
fluorodeoxy-D-glucose (shortly calledfluorodeoxy-D-glucose (shortly called
FDGFDG ) with an optimal half-life of) with an optimal half-life of
almost 2 hours and its ideal propertyalmost 2 hours and its ideal property
of giving precise values of energyof giving precise values of energy
metabolism not only for the brain ormetabolism not only for the brain or
heart but also for other organs.heart but also for other organs.
 The glucose is an important energeticThe glucose is an important energetic
substrate with a simple chemicalsubstrate with a simple chemical
formula which is amply metabolized byformula which is amply metabolized by
thethe neoplasticneoplastic cells.cells.

94. Examples ofExamples of
PET images:PET images:
☻☻EpilepsyEpilepsy
Pinpointing epileptic fociPinpointing epileptic foci
Most of the patients with epilepsy suffer fromMost of the patients with epilepsy suffer from
focal (partial) epilepsy that cannot be controlledfocal (partial) epilepsy that cannot be controlled
with medication. These patients may be goodwith medication. These patients may be good
candidates for resection of the affected area ofcandidates for resection of the affected area of
the brain; however, it is very difficult tothe brain; however, it is very difficult to
accurately identify the epilepsy focus. Insertingaccurately identify the epilepsy focus. Inserting
depth electrode implants is one method ofdepth electrode implants is one method of
locating the foci, but it is expensive, highlylocating the foci, but it is expensive, highly
invasive, and associated with high rates ofinvasive, and associated with high rates of
mortality, morbidity and infection.mortality, morbidity and infection.
PET is a non-invasive and cost-effective aid inPET is a non-invasive and cost-effective aid in
predicting the prognosis and in surgicalpredicting the prognosis and in surgical
planning for resection procedures. By revealingplanning for resection procedures. By revealing
areas of increased and decreased glucoseareas of increased and decreased glucose
utilization, PET helps surgeons pinpoint theutilization, PET helps surgeons pinpoint the
surgical site.surgical site.
Focal area of diminished FDG uptake in Rt. Frontal cortexFocal area of diminished FDG uptake in Rt. Frontal cortex

95. ☺☺AlzheimerAlzheimer
PET is being used to diagnose a widePET is being used to diagnose a wide
variety of dementias by showing avariety of dementias by showing a
distinct pattern of decreased glucosedistinct pattern of decreased glucose
consumption in the temporal/ parietalconsumption in the temporal/ parietal
regions of the brain, PET providesregions of the brain, PET provides
early detection of the disease andearly detection of the disease and
helps eliminating both the uncertaintyhelps eliminating both the uncertainty
associated with indefinite diagnosisassociated with indefinite diagnosis
and the need for multiple expensiveand the need for multiple expensive
tests.tests.
Marked reduction of FDG uptake in Rt. frontal, parietal & temporal regionsMarked reduction of FDG uptake in Rt. frontal, parietal & temporal regions

96. Other modalitiesOther modalities
 Plain X-ray:Plain X-ray:
◘◘ Plain X-ray skull is usually a routinePlain X-ray skull is usually a routine
investigation to be done in anyinvestigation to be done in any
suspected pathology to the head,suspected pathology to the head,
however it doesn’t give directhowever it doesn’t give direct
information as regards braininformation as regards brain
pathology.pathology.
◘◘ It can just demonstrate the effect ofIt can just demonstrate the effect of
brain pathology on skull bones asbrain pathology on skull bones as
widened sella turcica in pituitarywidened sella turcica in pituitary
adenomas.adenomas.
◘◘ It is replaced by the more informativeIt is replaced by the more informative
CT.CT.

97.  Cisternography:Cisternography:
It is the delineation of cisterns using contrast medium.It is the delineation of cisterns using contrast medium.
It can be done with -conventional X-ray.It can be done with -conventional X-ray.
-CT.-CT.
CT cisternography is done only to detect CSF leak:CT cisternography is done only to detect CSF leak:
.a lumber puncture is done to inject the contrast into lumber cistern, then the patient.a lumber puncture is done to inject the contrast into lumber cistern, then the patient
lies prone on the couch & coronal cuts are taken.lies prone on the couch & coronal cuts are taken.
.bilateral jugular pressure may help to show site of leak..bilateral jugular pressure may help to show site of leak.

98.  Ventriculography:Ventriculography:
This is delineation of ventricles.This is delineation of ventricles.
It can be done using contrast medium or air.It can be done using contrast medium or air.

99.  AirAir
meatography:meatography:
Done to detect suspected tumours of the 8Done to detect suspected tumours of the 8thth
cranial nerve.cranial nerve.
The patient lies in lateral decubitus with the affected sideThe patient lies in lateral decubitus with the affected side
up, 2-3 ml. of air is injected into the subarachnoidup, 2-3 ml. of air is injected into the subarachnoid
space through lumber puncture.space through lumber puncture.
Thin axial cuts are taken in region of internal auditoryThin axial cuts are taken in region of internal auditory
meatus, if tumour is present air will not pass to themeatus, if tumour is present air will not pass to the
meatusmeatus

100.  Thermography:Thermography:
It is the detection of cerebral blood flow throughIt is the detection of cerebral blood flow through
measurement of transmitted heat to foreheadmeasurement of transmitted heat to forehead..

101. Thank you