Dr.

Tayyaba Kiran
Lecturer
IIHS
ISLAMABAD

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Intracranial Hemorrhage
Active bleeding inside the cranial cavity
Types :
A. Epideural
B. Subdural
C. Subarachnoid
D. Intracerebral (intraparnchymal)
E. Intraventricular

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Epidural hematomas appear convex, or lens-
shaped, and do not cross suture lines.

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Subdural hematomas: appear convex, or
crescent-shaped, and may cross suture lines.

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Acute subdural hematoma. Note the bright (white)
image properties of the blood on this noncontrast
cranial computed tomography (CT) scan. 

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Subarachnoid hemorrhage appears as blood in the ventricles,
sulci, and cisterns. The overall sensitivity of CT is best within
the first 12 hours. Sensitivity declines with time and for more
minor bleeds.

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Cerebral (Intra-parenchymal) bleeds appear as
patches of bright white in the acute phase

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Skull fractures:

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MD Classification of brain tumors: a
framework
brain neoplasm

primary metastatic (breast15%)

(lungs50%)
extra-axial intra-axial
meningioma
neuronal glial astrocytoma
ependymoma
glioblastoma

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CNS Tumors
 Roughly one-third of CNS tumors are
metastatic lesions, one third are gliomas and
one-third is of non-glial origin.
Glioma is a non-specific term indicating that
the tumor originates from glial cells like
astrocytes, oligodendrocytes, ependymal and
choroid plexus cells.
Astrocytoma is the most common glioma and
can be subdivided into the high grade
malignant glioblastoma multiforme (GBM).

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 GBM is the most common type (50% of all
astrocytomas). 
The non-glial cell tumors are a large
heterogeneous group of tumors of which
meningioma is the most common

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 MRI is more sensitive than CT for detecting
brain tumors.

 CT is superior for detecting calcifications

within the lesion.

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Glioblastomas
 Glioblastomas are typically poorly-
marginated, diffusely infiltrating necrotic
masses localised to the cerebral
hemispheres. The supratentorial white matter
is the most common location. 

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 irregular thick margins: isodense to slightly
hyper attenuating (high cellularity)
 irregular hypodense centre representing

necrosis
 marked mass effect
 surrounding vasogenic oedema
 hemorrhage occasionally seen
 calcification is uncommon

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A meningioma is the most
common type of extra-axial neoplasm and
accounts for 14 - 20% of intracranial
neoplasm. It is a non-glial neoplasm that
originates from the arachnoids cap cells of
the meninges.

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 CT is often the first modality employed to
investigate neurological signs or symptoms, and
often is the modality which detects an incidental
lesion:
 non-contrast CT

60% slightly hyper dense to normal brain, the rest

are more iso dense
20-30% have some calcification 8
 post-contrast CT

72% brightly and homogeneously contrast

enhance 
malignant or cystic variants demonstrate more
heterogeneity/less intense enhancement
 enlargement of the para nasal sinuses has also been

suggested to be associated with anterior cranial

fossa meningiomas 
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Hydrocephalus
 Hydrocephalus is defined as an expansion of
the ventricular system on the basis of an
increase in the volume of cerebrospinal fluid
 Under absorption of cerebrospinal fluid

(communicating hydrocephalus)
 Restriction of the outflow of cerebrospinal

fluid from the ventricles (non communicating

hydrocephalus)

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Noncommunicating hydrocephalus.
 A, There is dilatation of the temporal horns (solid
white arrows) and the 4th ventricle is compressed
and nearly invisible (dotted white arrow).
 A hemorrhagic metastatic lesion (solid black

arrow) is present that is obstructing the 4th

ventricle.
 B, The frontal horns of the lateral ventricles ( L)

and 3rd ventricle (3) are dilated, but note that the
sulci are not dilated. This form of hydrocephalus
is the result of obstruction to the outflow of
cerebrospinal fluid from the ventricles.

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Communicating hydrocephalus.
Communicating hydrocephalus is due to
abnormalities that inhibit the resorption of
cerebrospinal fluid.
A, Classically, the 4th ventricle is dilated in
communicating hydrocephalus (4) but normal in
size as in non communicating hydrocephalus
B, The frontal horns (F), occipital horns (O), and
3rd ventricle (3) are markedly dilated.
Communicating hydrocephalus is usually
treated with a ventricular shunt.

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 Diffuse cortical atrophy. In general,
cerebral atrophy produces enlargement of the
sulci and the ventricles secondarily.
 CSF dynamics are normal in atrophy,

compared to hydrocephalus.
 Disorders that cause gross cerebral atrophy

are also associated with dementia, Alzheimer

disease being one of the most common.

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. A, The lateral ventricles (dotted white arrow) are enlarged. B,
Unlike hydrocephalus, the sulci are also enlarged ( solid white
arrows).

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 This CT shows a cross-sectional "slice" of the
abdomen. To understand the anatomy in this
image, visualize the patient lying on their
back. You are standing at the foot of the bed
looking towards the patients head.
 Major anatomical structures are labeled. A

tumor is visible in the head of the pancreas.

The arrow indicates the superior mesenteric
artery.

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Preparation of patient before CT:
  it is important that you are certain that a CT
scan is the best test to confirm or exclude the
condition(s) you suspect. 
 it is important to rule out pregnancy in a

female of child bearing age as this is usually

an absolute contraindication to CT.
 If the test you are requesting requires the

patient to have an iodinated contrast

injection, you should check that their renal
function is normal. 

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 Take off some or all of your clothing and
wear a hospital gown
 Remove metal objects, such as a belt, jewelry,

dentures and eyeglasses, which might

interfere with image results
 Refrain from eating or drinking for a few

hours before your scan

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Absolute contraindications for CT:

 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 should not be referred for scans where IVCM
is required to attain a diagnosis.
 Renal impairment may also prohibit your patient from having
IVCM.
 Hyperthyroidism or goiter may be a contraindication to the use
of IVCM as it may induce thyrotoxic crisis in these patients

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 Patients with myasthenia gravis have a small
increased risk of worsening of their
myasthenia, including respiratory muscular
weakness
 Check with the radiology department whether

your patient will require IVCM and what their

policies are regarding its use in the above
conditions.

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 Relative contraindications CT:
 All scanners will have weight limits that are
specified by the manufacturers. Newer
scanners have higher limits than their
predecessors with some able to
accommodate 220kg. 
 The gantry of the scanner is a fixed diameter

and if the patient cannot fit through the

gantry, the scan cannot be performed. A
common diameter is about 70cm.

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Contraindications against the use of ion-based contrast
media in patients:

 Children below 2 years of age

 Persons over 60 years of age
 Persons with complications after the previous administration
of a contrast medium
 Persons with acute and chronic circulatory and respiratory
failure
 Persons with hepatic and renal failure (also dialyzed patients)
 Persons with asthma and pulmonary edemas
 Persons with allergies
 Persons with insulin-dependent diabetes
 Persons with hypertension
 Persons with convulsions of cerebral etiology
 Persons with glaucoma

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Advantages: Highly detailed
 Of all the internal imaging procedures
available to physicians, the CT scan is the
most detailed, and can give a doctor the most
complete picture of what’s happening inside
a patient’s body. They are particularly useful
and widely used in diagnosing cancer.

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 Painless: The CT scan procedure is
noninvasive and painless, and is generally
quick and convenient for most patients. It’s
widely available at a range of different
treatment centers.

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 Precise: Because CT scan gives a doctor a very
clear picture of where a tumor or other
problem is located and whether it has spread,
it can help her in planning a biopsy, surgery,
radiation or other treatment with more
precision.

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Benefits
 CT scanning is painless, noninvasive and accurate.
 A major advantage of CT is its ability to image bone,
soft tissue and blood vessels all at the same time.
 Unlike conventional x-rays, CT scanning provides
very detailed images of many types of tissue as well
as the lungs, bones, and blood vessels.
 CT examinations are fast and simple; in emergency
cases, they can reveal internal injuries and bleeding
quickly enough to help save lives.
 CT has been shown to be a cost-effective imaging
tool for a wide range of clinical problems.

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 CT is less sensitive to patient movement than MRI.
 CT can be performed if you have an implanted
medical device of any kind, unlike MRI.
 CT imaging provides real-time imaging, making it
a good tool for guiding minimally
invasive procedures such as needle
biopsies and needle aspirations of many areas of
the body, particularly the lungs, abdomen, pelvis
and bones.
 A diagnosis determined by CT scanning may
eliminate the need for exploratory surgery and
surgical biopsy.
 No radiation remains in a patient's body after a CT
examination.
 X-rays used in CT scans should have no immediate
side effects.
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Disadvantages:
 Radiation Compared to other diagnostic tests,
CT scans deliver a relatively high dose of
radiation to the patient. While this is not
usually a problem for a single scan, patients
who need to undergo repeated tests can be
subjected to a significant level of radiation,
increasing their cancer risk
 Allergic Reaction

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 Misinterpretations: Because a CT scan is so
detailed, it can sometimes alert doctors to
minor abnormalities in the body that don’t
have symptoms related to them and that in
the normal course of life would not have
caused the patient any problems.

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Thanks 

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