2. Anatomy &
Physiology

3. BRAIN
• is one of the largest and
most complex organ in the
human body.
• The adult human brain
weighs on average about 3
lbs. (1.5 kg)with a volume
of around 1130 cubic
centimeters (cm3) in
women and 1260 cm3 in
men

4. • Our brain gives us awareness of
ourselves and of our environment,
processing a constant stream of
sensory data.
• It controls our muscle movements,
the secretions of our glands, and
even our breathing and internal
temperature.
• Every creative thought, feeling, and
plan is developed by our brain.
• The brain’s neurons record the
memory of every event in our lives.

5. IT HAS THREE MAIN PARTS:
•Cerebrum
• the largest part of the mature brain.
• It consists of two large masses, called
cerebral hemispheres, which are
almost mirror images of each other.
• The cerebrum is concerned with
higher brain functions, interpreting
sensory impulses and initiating
muscle movements.
• It stores information and uses it to
process reasoning.
• It also functions in determining
intelligence and personality.

6. • The surface of the cerebrum has a
folded appearance called the cortex.
• The cortex contains about 70% of
the 100 billion nerve cells.
• The nerve cell bodies color the
cortex grey-brown giving it its name
– gray matter.
• Beneath the cortex are long
connecting fibers between neurons,
called axons, which make up the
white matter.

7. •Cerebellum
• a rounded structure located
behind the brain stem, to which
it is linked by thick nerve tracts.
• It accounts for about 11% of
the whole brain weight and
appears similar to the
cerebrum.
• It is concerned mainly with the
maintenance of posture and
balance and the coordination of
movement.

8. •Brain Stem
• Houses the midbrain
(mesencephalon), pons (part of
the metencephalon), and medulla
oblongata (myelencephalon).
• This is the posterior area of the
brain that attaches to the spinal
cord.
• It's here, at the brain stem, where
information is sent back and forth
between the cerebrum or
cerebellum and the body.
• Cranial nerves 3-12 are located
here as well as significant
processing centers.

9. THE BRAIN IS ALSO DIVIDED INTO
SEVERAL LOBES:
Frontal lobe
• Personality, behavior,
emotions,
• Judgment, planning,
problem solving
• Speech: speaking and
writing (Broca’s area)
• Body movement (motor
strip)
• Intelligence, concentration,
self awareness
Parietal lobe
• Interprets language, words
• Sense of touch, pain,
temperature (sensory strip)
• Interprets signals from
vision, hearing, motor,
sensory and memory
• Spatial and visual perception

10. Occipital lobe
• Interprets vision (color,
light, movement)
Temporal lobe
• Understanding language
(Wernicke’s area)
• Memory
• Hearing
• Sequencing and organization

12. DEEP STRUCTURES
• Hypothalamus - is located in the
floor of the third ventricle and is the
master control of the autonomic
system. It plays a role in controlling
behaviors such as hunger, thirst,
sleep, and sexual response. It also
regulates body temperature, blood
pressure, emotions, and secretion of
hormones.

13. • Pineal gland - is located behind the third
ventricle. It helps regulate the body’s
internal clock and circadian rhythms by
secreting melatonin. It has some role in
sexual development.
• Thalamus - serves as a relay station for
almost all information that comes and goes
to the cortex. It plays a role in pain
sensation, attention, alertness and memory.

14. • Basal ganglia - includes the caudate,
putamen and globus pallidus. These nuclei
work with the cerebellum to coordinate
fine motions, such as fingertip
movements.
• Limbic system - is the center of our
emotions, learning, and memory. Included
in this system are the cingulate gyri,
hypothalamus, amygdala (emotional
reactions) and hippocampus (memory).

16. SKULL
• The purpose of the bony skull is to protect the
brain from injury.
• The skull is formed from 8 bones that fuse together
along suture lines.
• These bones include the frontal, parietal (2),
temporal (2), sphenoid, occipital and ethmoid.
The face is formed from 14 paired bones
including the maxilla , zygoma, nasal, palatine,
lacrimal, inferior nasal conchae, mandible, and
vomer.

20. CT scanning of the head is typically used to detect:
• bleeding, brain injury and skull fractures in patients with
head injuries.
• bleeding caused by a ruptured or leaking aneurysm in a
patient with a sudden severe headache.
• a blood clot or bleeding within the brain shortly after a
patient exhibits symptoms of a stroke.
• a stroke, especially with a new technique called Perfusion CT.
• brain tumors.
• enlarged brain cavities (ventricles) in patients with
hydrocephalus.
• diseases or malformations of the skull.

21. CT scanning is also performed to:
• evaluate the extent of bone and soft tissue damage in patients with
facial trauma, and planning surgical reconstruction.
• diagnose diseases of the temporal bone on the side of the skull, which
may be causing hearing problems.
• determine whether inflammation or other changes are present in the
paranasal sinuses.
• plan radiation therapy for cancer of the brain or other tissues.
• guide the passage of a needle used to obtain a tissue sample (biopsy)
from the brain.
• assess aneurysms or arteriovenous malformations through a technique
called CT angiography.

23. • CT scanning has no absolute contraindications.
• But due to the relatively high radiation dose
involved in CT scans, it is important to avoid
scanning patients who are pregnant. Radiation
exposure to a fetus can cause developmental
problems. Thus, CT should only be performed for
pregnant patients in critical situations and only
after discussion of the potential risks.
• Patients who have an allergy to the IV contrast
media (IVCM) used in CT scans.
• Renal impairment may also prohibit your patient
from having IVCM.

25. Before the CT scan, tell your doctor if you:
• Are or might be pregnant.
• Are allergic to any medicines, including iodine dyes.
• Have a heart condition, such as heart failure.
• Have diabetes or take metformin (Glucophage) for your
diabetes. You may have to adjust your medicine for a day
before and after the test.
• Have had kidney problems.
• Have asthma.
• Have a medical device, such as a pacemaker or an insulin
pump.
• Become very nervous in small spaces. You need to lie still
inside the CT scanner, so you may need a medicine (sedative)
to help you relax.

26. • You should wear comfortable, loose-fitting
clothing to your exam. You may be given a
gown to wear during the procedure.
• Metal objects, including jewelry, eyeglasses,
dentures and hairpins, may affect the CT
images and should be left at home or
removed prior to your exam. You may also be
asked to remove hearing aids and removable
dental work. Women will be asked to remove
bras containing metal underwire. You may be
asked to remove any piercings, if possible.

27. • If your procedure involves the use of
contrast dye, you will be asked to sign a
consent form that gives permission to do the
procedure. Read the form carefully and ask
questions if something is not clear.
• Generally, there is no fasting requirement
prior to a CT scan, unless a contrast dye is to
be used. Your doctor will give you special
instructions ahead of time if contrast is to be
used and if you will need to withhold food
and drink.

28. • Procedure with contrast:
• Kidney function test (BUN and Creatinine)
must be done 72 hrs. before the procedure.
• NPO (4 hours) before the procedure.
• You may drink clear liquids up until the
time of your scan. Clear liquids include
water, black coffee or tea, apple juice, clear
soda or clear broth.
• Secure a consent form.

33. CONTRAST MEDIA
• (Iopamiro/Ultravist)
>300 mg I/mL and 370 mg I/mL

35. • You will lie on a scan table that slides into a large, circular
opening of the scanning machine. Your head may be
immobilized to prevent movement during the procedure.
• The technologist will be in another room where the scanner
controls are located. However, you will be in constant sight of
the technologist through a window. Speakers inside the
scanner will enable the technologist to communicate with
and hear you. You may have a call button so that you can let
the technologist know if you have any problems during the
procedure. The technologist will be watching you at all times
and will be in constant communication.
• As the scanner begins to rotate around you, X-rays will pass
through the body for short amounts of time. You will hear
clicking sounds, which are normal.

36. • The X-rays absorbed by the body's tissues will be
detected by the scanner and transmitted to the
computer. The computer will transform the
information into an image to be interpreted by the
radiologist.
• It will be very important for you to remain very still
during the procedure. You may be asked to hold
your breath at various times during the procedure.
• If contrast dye is used for your procedure, you will
be removed from the scanner after the first set of
scans has been completed. A second set of scans will
be taken after the contrast dye has been
administered.

37. • If contrast dye is used for your procedure, you may
feel some effects when the dye is injected into the
IV line. These effects include a flushing sensation, a
salty or metallic taste in the mouth, a brief
headache, or nausea and/or vomiting. These effects
usually last for a few moments.
• You should notify the technologist if you feel any
breathing difficulties, sweating, numbness, or heart
palpitations.
• When the procedure has been completed, you will
be removed from the scanner.

38. • If an IV line was inserted for
contrast administration, the line
will be removed.
• You may be asked to wait for a
short period of time while the
radiologist examines the scans to
make sure they are clear.

40. • If contrast dye was used during your procedure,
you may be monitored for a period of time for
any side effects or reactions to the contrast dye,
such as itching, swelling, rash, or difficulty
breathing. Notify the radiologist or your doctor
if you experience any of these symptoms.
• If you notice any pain, redness, and/or swelling
at the IV site after you return home following
your procedure, you should notify your doctor
as this could indicate an infection or other type
of reaction.

41. • Otherwise, there is no special type of care required
after a CT scan of the brain. You may resume your
usual diet and activities unless your doctor advises
you differently.
• Your doctor may give you additional or alternate
instructions after the procedure, depending on
your particular situation.
• If you are a diabetic who takes any medication that
contains metformin, you must have a blood test to
check your kidney function before you can start
taking metformin again. Call your doctor for the
results of the blood test and for instructions about
resuming metformin.

43. ROUTINE ADULT HEAD (BRAIN)
PATIENT POSITIONING:
• • Patient should be supine, head first into the gantry, with the head in the
head-holder whenever possible.
• • Center the table height such that the external auditory meatus (EAM) is at
the center of the gantry.
• • To reduce or avoid ocular lens exposure, the scan angle should be parallel
to a line created by the supraorbital ridge and the inner table of the
posterior margin of the foramen magnum.
• This may be accomplished by either tilting the patient’s chin toward the
chest (“tucked” position) or tilting the gantry.
• While there may be some situations where this is not possible due to
scanner or patient positioning limitations, it is considered good practice to
perform one or both of these maneuvers whenever possible.
• SCAN RANGE: Top of C1 lamina through top of calvarium.

44. CONTRAST:
• Oral: None.
• Injected: Some indications require injection of intravenous or
intrathecal contrast media during imaging
• of the brain.
• Intravenous contrast administration should be performed as
directed by the supervising radiologist
• using appropriate injection protocols and in accordance with
the ACR Practice Guideline for the Use of Intravascular
Contrast Media. A typical amount would be 100 cc at 300
mg/cc strength, injected at 1 cc/sec. A delay of 4 minutes
between contrast injection and the start of scanning is
typical.

45. AXIAL VERSUS HELICAL SCAN MODE (both are
provided in the following sample protocols):
• There are advantages and disadvantages to using
either axial or helical scans for routine head CT
exams. The decision as to whether to use axial or
helical should be influenced by the specific patient
indication, scanner capabilities, and image quality
requirements.
• Users of this document should consider the
information in the following table and consult with
both the manufacturer and a
• medical physicist to assist in determining which
mode to use.

57. SCOUT: LATERAL
LANDMARK: OML
SLICE PLANE: CORONAL & AXIAL
I.V. CONTRAST: 100-140 ML
BREATH HOLD: NONE
DFOV
SLICE THICKNESS: 1-1.5 mm
12
FILMING: BONE & SOFT TISSUE
PITUITARY AND SELLA TURCICA

58. PATHOLOGY

59. EPIDURAL HEMATOMA
• An epidural hematoma is
usually associated with a
skull fracture. It often
occurs when an impact
fractures the calvarium.
The fractured bone
lacerates a dural artery or
a venous sinus. The blood
from the ruptured vessel
collects between the skull
and dura.
Biconvex (lenticellular) epidural
hematoma (arrowheads),
deep to the parietal skull fracture
(arrow).

60. SUBARACHNOID
HEMORRHAGE
• A subarachnoid hemorrhage occurs
with injury of small arteries or veins on
the surface of the brain. The ruptured
vessel bleeds into the space between
the pia and arachnoid matter. The most
common cause of subarachnoid
hemorrhage is trauma. In the absence of
significant trauma, the most common
cause of subarachnoid hemorrhage is
the rupture of a cerebral aneurysm.
High density blood (arrowheads)
fills the sulci over the
right cerebral convexity in this
subarachnoid hemorrhage.

61. SUBDURAL HEMATOMA
• is a type of hematoma,
usually associated
with traumatic brain injury.
• Blood gathers with the
outermost meninges layer,
between the dura mater,
which adheres to the skull,
and the arachnoid mater,
which envelops the brain.
High density, crescent shaped
hematoma (arrowheads)
overlying the right cerebral
hemisphere. Note the shift of the
normally midline septum
pellucidum due to the mass effect
arrow.

62. HEMORRHAGIC
STROKE
• are due to rupture of a
cerebral blood vessel
that causes bleeding
into or around the brain
Hemorrhage in the cerebellum (arrow).

63. HYDROCEPHALUS
• Hydrocephalus, a problem with the ratio of
production of CSF to its re-absorbtion, is
most frequent in children.

64. INTRACRANIAL
TUMOR
• Intracranial tumors
generally present
with a focal
neurological deficit,
seizure, or
headache.
Multiple enhancing masses located at
the grey-white junction zones.

65. MENINGIOMA
• Meningiomas are the
most common extraaxial neoplasm of the
brain. Middle-aged
women are most
frequently affected.
Twenty percent of
meningiomas calcify.
On CT, meningiomas
are usually isointense
to gray matter.
Axial, post contrast CT demonstrating
broad based enhancing extra-axial mass.

66. CT IMAGES

67. A. Orbit
B. Sphenoid Sinus
C. Temporal Lobe
D. External Auditory Canal
E. Mastoid Air Cells
F. Cerebellar Hemisphere

68. A. Frontal Lobe
B. Frontal Bone (Superior Surface of Orbital Part)
C. Dorsum Sellae
D. Basilar Artery
E. Temporal Lobe
F. Mastoid Air Cells
G. Cerebellar Hemisphere

69. A. Frontal Lobe
B. Sylvian Fissure
C. Temporal Lobe
D. Suprasellar Cistern
E. Midbrain
F. Fourth Ventricle
G. Cerebellar Hemisphere

70. A. Falx Cerebri
B. Frontal Lobe
C. Anterior Horn of Lateral Ventricle
D. Third Ventricle
E. Quadrigeminal Plate Cistern
F. Cerebellum

74. THE END
Re p o r t e d b y :
J o a n C. Va r g a s