Investigations of MS

Question 1

funcion of x ray

Answer 1

to detect skull fractures after head trauma

Question 2

positioning for X Ray

Answer 2

AP
PA
Lateral

Question 3

Function of computerised tomography

Answer 3

detect acute haemorrhage
assess depressed and comminuted skull fractures
can visual bleeding e.g. extradural haematomas, subdural haematomas, actively bleeding parenchymal haemorrhages, brain herniation

Question 4

describe density in computerised tomography

Answer 4

white = most dense
black = least dense

Question 5

process of cerebral angiography

Answer 5

catheter inserted in femoral artery and manouvered to carotid or vertebral origin
contrast injected with high pressure pump

Question 6

benefits of cerebral angiography

Answer 6

• Disorders of the cerebrovascular circulation
• Aneurysm
• Arterio-venous malformation
• Transient ischaemic attack
• Cranial arteritis
• Vascular tumour (haemangioblastoma, angioma)

Question 7

describe process of MRI

Answer 7

Magnetic field forces H+ protons in body to orient to that field.
radiofrequency is pulsed through patient protons spin out of equilibrium
current switched off and MRI detects energy released when protons re-align w/ magnetic field
MRI - map of proton energy within tissue

Question 8

benefits of using T1 weighted MRI

Answer 8

Better contrast between gray and white matter

Question 9

benefits of using T2 weighted MRI

Answer 9

scans better for oedema

Question 10

what colour is; water, fat, bone, inflammation, muscle, spinal cord, cortex, white matter in T1 weighted MRI

Answer 10

water - dark
fat - bright
bone - dark
inflammation - dark
muscle - grey
spinal cord - grey
cortex - grey
white matter - bright (myelin or fat sheath in axons)

Question 11

what colour is; water, fat, bone, inflammation, muscle, spinal cord, cortex, white matter in T1 weighted MRI

Answer 11

water - bright
fat - bright
bone - dark
inflammation - bright
muscle - dark grey
spinal cord - light grey
cortex - light grey
white matter - dark grey (myelin or fat sheath in axons)

Question 12

absolute contraindications for MRI

Answer 12

Ferrous metallic foreign bodies - old gunshot shrapnel, older types of fracture fixation
implanted electrical medical devices - cochlear, pacemaker, insulin pump
pregnancy
claustrophobic

Question 13

purpose of lumbar puncture

Answer 13

obtain CSF

Question 14

Positioning for lumbar puncture

Answer 14

side lying knees to chest
needle in L4-L5

Question 15

Precautions for lumbar puncture

Answer 15

• Raised CSF
• Tentorial herniation-coning

Question 16

what is an elevated white cell count in CSF indicative of

Answer 16

metastatic tumour

Question 17

what is an elevated erythrocyte cell count in CSF indicative of

Answer 17

encephalitis

Question 18

what is an protein in CSF indicative of

Answer 18

polyradiculitis or guillain barre syndrome

Question 19

what is the presence of oligoclonal bands in CSF indicative of

Answer 19

IgG synthesis - MS

Question 20

Contraindications of lumbar puncture

Answer 20

• Raised intra-cranial pressure (ICP)
• Coagulation disorder
• Vertebral deformity

Question 21

process of positron emission tomography

Answer 21

radiation introduced in body using radiotracer
radiation accumulates in organs and measured when it emits small energy - gamma rays which ill be detected
indicate body function e.g blood flow, oxygen uptake

Question 22

complications of lumbar puncture

Answer 22

Headache (10%)
Radicular pain (10%)
Tonsillar herniation (extremely rare)

Question 23

function of muscle biopsy

Answer 23

Essential in diagnosis of
inflammatory myopathies
metabolic myopathies

Question 24

process of electro-encephalography

Answer 24

Recording of cerebral electrical potentials by electrodes on the scalp
* Abnormalities reflect general pathological processes NOT specific diagnoses

Question 25

Electro-encephalography detects what pathological conditions

Answer 25

• Epilepsy
• States of altered consciousness
  Post traumatic and anoxic coma
• Parasomnias
• Dementias
• Toxic confusional states
• Cerebral infections
• Encephalopathies

Question 26

describe electromyography process

Answer 26

Recording of electrical activity within a muscle
Diagnostic EMG involves insertion of needles into muscle to
record and observe motor unit action potentials

Question 27

nerve conduction studies

Answer 27

• Peripheral nerve (motor or sensory) stimulated
• Time from stimulus  response (muscle contraction) is calculated
• Conduction velocity = distance between two sites divided time taken

Question 28

factors affecting nerve conduction studies

Answer 28

• Age
• Body Temperature
• Pathology
  Delay occurs with
  Nerve entrapments
  Demyelinating polyneuropathy
  Multifocal motor neuropathy
• Repeated stimulation: Myasthenia Gravis

Question 29

describe evoked potentials

Answer 29

Measure the electrical activity of the brain in response to stimulation of specific sensory nerve pathways

Question 30

types of evoked potentials

Answer 30

visual - diagnose ms
Somatosensory - monitoring during surgery
Motor - via transcranial magnetic stimulation of head

Question 31

electronystagmography

Answer 31

Electrical measurement of
nystagmus (abnormal
beating of the eyes)