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8/12/2019 Special Studies in Neurology
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SPECIAL STUDIES IN NEUROLOGY
dr. ASHARI BAHAR, M.Kes, Sp.S, FINS
DEPARTMENT OF NEUROLOGY
FACULTY OF MEDICINE
UNIVERSITY OF HASANUDDIN2011
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Whenever an ancillary diagnostic test isproposed, the specific indication for the test
should be considered carefully and critically: Only after thorough and meticulous clinical history taking and neurological examination.
Only after the formulation of a clinical differential diagnosis, in which all of the competing
diagnoses are ranked by probability.
The study that should be performed is the one whose result is most likely to be important
for further diagnostic and therapeutic management, but only if this will be of clear benefit tothe patient, and only if the risks of performing the study do not outweigh any potential
benefit that its findings might bring.
Multiple studies providing the same diagnostic information should not be performed merely
for repeated confirmation of the findings.
A study should not be performed if, regardless of its result, another study will have to be
performed that is likely to yield at least as much information. Only very rarely should studies be performed to confirm a diagnosis that is already
practically certain.
If a genetic study is contemplated, the potential consequences should be discussed
thoroughly with the patient and his or her family before the study is performed.
The costs must not be forgotten.
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CSF StudiesMyelography and
Radiculography
Basic studies
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Cerebrospinal Fluid Studies
Indications
Lumbar puncture is useful in the diagnosis of
diseases affecting the meninges, the brain and
spinal cord, and the nerve roots, which can
manifest themselves with changes in the
biochemical or cellular properties of the
cerebrospinal fluid.
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Cerebrospinal Fluid Studies
Indications
Diagnostic
Therapeutic
Follow up
Anesthetic
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foramen of
Magendie
Cerebral
aqueduct
(Sylvius)
foramen of
Luschka
Choroid
plexus of
lateral
ventricle
foramen
Monro
Choroid
plexus of3rd ventricleChoroid
plexus of 4th
ventricle
Subarachnoid
space
Subarachnoid
space
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Cerebrospinal Fluid Studies
Patient position for lumbar puncture
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Cerebrospinal Fluid Studies
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Clinically relevant CSF Studies
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Myelography and Radiculography
Technique
Radiculomyelography (the visualization of intraspinal structures with
contrast medium) is generally performed after the injection of 1015 ml of
watersoluble contrast medium into the subarachnoid space via lumbarpunctureor, rarely, via suboccipital puncture.
The passage of contrast medium through the subarachnoid space,
including the nerve root sleeves, can then be followed on the radiologic
image and any obstructions to the flow of contrast medium can be identified
(e. g., spinal tumors).
The nerve roots appear as filling voids within the nerve root sleeves.The bony spine is seen on the myelographic images as well and can be
evaluated at the same time.
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Myelography and Radiculography
IndicationsClinically evident lumbar radiculopathy with unclear CT findings
Suspected radiculopathy, but no clear segmental localization
Suspected spinal cord compressionSuspected spinal stenosis
Clinically evident spinal stenosis
Suspected myelopathy due to cervical spondylosis
Suspected myelitis or demyelination
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Myelography and Radiculography
Typical findings in contrast myelography
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Imaging Studies
Skull radiographs Plain radiographs of the spine
Conventional SkeletalRadiographs
Myelography and
Radiculography
CT AngiographyComputed Tomography (CT)
MR AngiographyMagnetic Resonance
Imaging (MRI)
Angiography withRadiological Contrast Media
Diagnostic Techniques of
Nuclear Medicine
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Conventional Skeletal Radiographs
Skull radiographs
Skull radiographs are performed for very few purposes
nowadays and are hardly ever indicated.
(They cannot be used as a substitute for CT in head
trauma; if a CT is indicated, but unavailable for some
reason, then the patient should probably be transportedto a center where a CT can be performed.)
Plain films of the skull enable visualization of:
fractures (though much less well than on CT)
congenital malformations of the bony skull, and
various developmental disorders
Skull radiographs are useless in the diagnostic
evaluation of headache or intracranial processes.
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Conventional Skeletal Radiographs
Plain radiographs of the spine
Plain radiographs of the spine are sometimes useful for
the demonstration of:
fractures,
bony tumors (which, however, are more easily seen by CT or MRI),
degenerative diseases and slippage (olisthesis) of
the spine,
infections involving bone,
axial skeletal deformities,
dynamic abnormalities (abnormal mobility or
instability of individual spinal segments; their
demonstration requires special radiological
techniques, socalled functional studies).
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Conventional Skeletal Radiographs
Skull fracture seen in a plain skull radiograph.
The (a) and (b) images both reveal a fracture line medial to the
lambdoid suture on the right (arrow).
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Computed Tomography (CT)
Normal CT scan of the head. a Note the symmetrical,
normal-sized frontal and occipital horns of the lateral ventricles.
The cerebral cortex and deep white matter can be distinguished from each other, and the falx cerebri
can be seen in both the frontal and occipital regions. A number of blood vessels can be seen.
Also note the bilateral calcifications of the choroid plexus of the lateral ventricles.
b. Some of the blood vessels around the base of the brain (arrows) are well seen after the
administration of contrast medium.
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Magnetic Resonance Imaging (MRI)
ah Normal MRI of the brain in 5 mm sections from the base of
the brain to the vertex
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Comparative indications of CT and MRI of the head
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Angiography with Radiological Contrast
Media
Diagnostic imaging of the
cerebral blood vessels is
indicated when a vascularstenosis, occlusion, or
malformation is suspected as
the cause of a neurological
illness.
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Angiography with Radiological Contrast
Media
Indications for angiography of the intracranial vessels Visualization of saccular aneurysms
Visualization of arteriovenous malformations and fistulae
Detailed representation of saccular aneurysms (after diagnosis by
MRI, as an aid to treatment by neurosurgical or interventional
neuroradiological methods) Detailed representation of arteriovenous malformations (after
diagnosis by MRI, as an aid to treatment by neurosurgical or
interventional neuroradiological methods)
Visualization of other vascular anomalies:
moyamoya
agenesis of vessels and other developmental anomalies
vascular stenosis or occlusion
arterial dissection
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Electrophysiological Studies
Electroencephalography(EEG)
Polysomnography (PSG)
Visual evoked potentials (VEP)Auditory evoked potentials (AEP)
Somatosensory evoked potentials (SSEP)
Motor evoked potentials (MEP)
Evoked potentials
Electromyography (EMG)
Electroneurography (ENG)
Oculography
Electronystagmography
Retinography
Other Electrophysiological
Studies
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Electroencephalography (EEG)
Principle
The surface EEG registers fluctuations in electrical
potential that are generated by the cerebral
cortex.
These represent the sum of the excitatory and
inhibitory synaptic potentials.
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Electroencephalography (EEG)
The main indications for electroencephalography
Confirmation of the diagnosis of epilepsy
Determination of the type of epilepsy that is present
Brief, episodic impairment of consciousness of
unknown etiology
Longer-lasting disturbances of consciousness, delirium
Metabolic disturbances CreutzfeldtJakob disease
Sleep studies (e. g., in suspected narcolepsy)
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Electroencephalography (EEG)
Placement of EEG electrodes according to the 1020 system
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Electroencephalography (EEG)
Normal EEG. a Monopolar recording, b bipolar recording.
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Polysomnography (PSG)
Technique
Polysomnography is a special application of EEG in which the EEG is
recorded simultaneously with a number of other electrophysiological
parameters.
It is used to assess sleep and sleep disturbances. The EEG changes that normally occur during sleep are related to the
progression of the individual through various sleep stages, including
deep or REM sleep (REM = rapid eye movement).
The recorded parameters include eye movements (by electro-
oculography), respiratory excursion, airflow in the nostrils, muscleactivity (by surface EMG), cardiac activity (by ECG), and the partial
pressure of oxygen (by transcutaneous pulse oximetry)
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Polysomnography (PSG)
Indications
The most important indication for a sleep study is
a clinical suspicion of sleep apnea syndromeon
the basis of a characteristic history obtained fromthe patient or bed partner, together with related
physical findings and a low partial pressure of
oxygen measured during sleep by pulse oximetry.
Polysomnography is also indicated for the
diagnosis of narcolepsy, as well as for the
assessment of excessive fatigue and daytime
somnolence.
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Polysomnography (PSG)
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Polysomnography (PSG)
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Indications
In disorders affecting muscle, EMG
can be used to determine whether
the underlying pathological process
is located in the muscle itself
(myopathic process), in the nerveinnervating it (neuropathic
process), or at the neuromuscular
junction.
It can also be used to grade the
severity of muscle denervation and
the extent of reinnervation.
In combination with
electroneurography (see below),
EMG is a very important type of
ancillary study for the diagnosis of
neuromuscular diseases.
Electromyography (EMG
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Electromyography (EMG
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Electroneurography (ENG)
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Indications for EMG and ENG
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Ultrasonography
There are two main types of
ultrasound study:
Doppler sonography
duplex sonography
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Ultrasonography
Indications
The velocity and flow profile (laminar or turbulent) of the
blood flowing within a particular vessel depend, among
other things, on the vessels caliber and on the nature of
its wall.
Ultrasound studies aid in the detection of vascular stenosis
and occlusion, vessel wall irregularities, abnormalities of
the speed and direction of blood flow, and turbulent flow.
Insonation of the extra- and intracranial vessels (e. g., of
the middle cerebral a. through the thin bone of the
temporal window, or of the basilar a. through the
foramen magnum) yields an informative picture of the
current state of blood flow in the brain.
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Ultrasonography
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Ultrasonography
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Ultrasonography
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Other Ancillary Studies
Tissue Biopsies
Muscle biopsy
Nerve biopsy
Brain biopsy
Perimetry
Static computed perimetry
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Automatic (Octopus) perimetry in right
homonymous hemianopsia
Perimetry is used to detect visual field defects
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