Medical technologies and pathology in the nervous system

Question 1

How to diagnose pathology in the nervous system?

Answer 1

• Talk to the patient – medical history
• Neurological examination: strength, reflexes, sensory deficits
• Imaging

Question 2

Give some examples of modern imaging techniques.

Answer 2

Modern imaging techniques

• Neuroradiology – Plain X-ray
• CT = Computed Tomography
• MRI = Magnetic Resonance
• Imaging Angiography
• Neurophysiology – EEG, ENG, EMG
• Ultrasonography
• Nuclear methods (SPECT, PET)

Question 3

Give examples of techniques and technologies used in treatment of pathology in the NS.

Answer 3

Techniques and technologies used in treatment

• Neurosurgical operations
• Aneurysmal clipping and coiling
• Ventricular drain
• Cerebral pressure monitoring devices
• Operating microscope
• Neuronavigation systems

Question 4

Give examples of Pathology in the NS.

Answer 4

Pathology

• Head trauma
• Tumors
• Epilepsy
• Stroke

Question 5

Shortly describe CT

Answer 5

Computed Tomography

• Traumatic changes –bleeding, swelling, fractures
• Tumors
• Takes 10-20 minutes
• Radiation potentially harmful
• The first CT 1972
• Godfrey Hounsfield
• Attenuation - density
• Hounsfield units

water = 0 HU

Bone =1000 HU

•i.v. contrast

Question 6

What is CAT?

Answer 6

Computed axial tomography - CAT

Mathematic reconstruction of attenuation of tissue measured by letting x-ray beams pass through an object.

Question 7

What is ICP?

Answer 7

Raised intracranial pressure

• Normal ICP in adults 0-15 mmHg
• Raised ICP can occur in trauma, stroke or tumors

Question 8

How to decrease ICP?

Answer 8

The intracranial volume:

• Brain
• Blood
• CSF

If bleeding or swelling occurs, the other compounds must decrease.

In the acute setting you can compensate for ca 50 ml by decreasing CSF and blood volume without increase in ICP

Question 9

Describe how to monitor ICP.

Answer 9

Intracranial pressure monitoring

1. Ventricular drain
   
   • Measure pressure
   • Drain CSF
2. Intraparenchymal pressure monitoring device
   
   • Measure pressure
3. Quickly discover swelling and/or bleeding

Question 10

Explain MRI.

Answer 10

Magnetic resonance tomography imaging - MRI

Certain atomic nuclei in the tissues are affected and aligned by a strong magnetic field – react as compasses.

Through a radio frequency disturbance the nuclei will “tip” and energy will be released. The energy can be detected and the information can be used to create an image.

• First MRI on a person – 1977
• Nobel prize 2003
• Takes up to 1 hour
• No harmful radiation (children, pregnant women)
• Important – avoiding metal objects

Question 11

Explain DAI.

Answer 11

Diffuse Axonal Injury - DAI

•Also called shearing injury

–Tearing of nerve fibers (axons)

–High velocity injuries

–Severe acceleration-deceleration trauma

Question 12

Explain different aspects of Brain tumors.

Answer 12

Brain Tumors

• Primary
• Secondary – metastasis
• Malignant - Benign

Symptoms and clinical findings

• Headache
• Epilepsy
• Focal neurological deficits

Question 13

Describe fMRI.

Answer 13

Functional MRI – fMRI

Activation of an area of the brain increases blood flow in this area, leading to increase of oxyhemoglobine (oxygenated blood) and decrease in deoxyhemoglobin. Deoxyhemoglobine is paramagnetic.

Question 14

Explain Ultrasonography.

Answer 14

Ultrasonography

• Soundwaves with frequecy above what humans can hear
• Piezoelectric transducer - 2-18 MHz
• Interpretation of reflected waves
• Different tissues have different reflecting capabilities

Question 15

Describe Epilepsy

Answer 15

Epilepsy

”abnormal, repetetive, syncronous excharges in nerve cells in the cerebral cortex”

• Congenital
• Post trauma
• Tumors
• Stroke
• Alzheimer

•

•

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Question 16

What is EEG?

Answer 16

EEG

Electroencefalogram – neurophysiologic examination – registration of rhythmic electric activity from the cortex cerebri.

Question 17

List different Imaging Techniques used to examine the brain.

Answer 17

Imaging Tecniques

• CT
• MR
• SPECT
• PET

Question 18

Explain SPECT.

Answer 18

SPECT - Single Photon Emission Computed Tomography

A radioactive substance is infused – gamma radiation is detected.

Question 19

Explain PET

Answer 19

PET – positron emission tomography

Labeled biological active molecules is infused.

Question 20

Explain Stroke.

Answer 20

Stroke

• Bleeding or infarction (oxygen depletion) in the brain
• Hypertension, atherosclerosis, emboli (blood clots), aneurysm
• CT

Question 21

Explain Subarachnoid Bleeding.

Answer 21

Subarachnoid Bleeding

•Often bleeding due to an aneurysm that has ruptured

Question 22

What is an aneurysm?

Answer 22

Aneurysm

Pathological distension of blood vessel.

Question 23

Explain Cerebral angiography.

Answer 23

Cerebral angiography

Contrast medium is injected and x-ray is used to study the vascular system of the brain.

Question 24

Treatment to Aneurysm?

Answer 24

Treatment

• Clipping (Surgery)
• Coiling (Endovascular treatment)