Radiology Department, Faculty of Medicine
BASIC
NEURORADIOLO
GY
Sianny Suryawati
Radiology Department, Faculty of Medicine
Wijaya Kusuma University, Surabaya
2015
Outline
•
•
•
•
•
Normal Imaging Anatomy of Brain
Basic Features of Brain Lesions
Brain Tumor
Cerebrovascular Disease
Traumatic Brain Injury
Normal Imaging Anatomy of
Brain
•
•
•
•
•
•
•
Skull and Meninges (Dura, Pia)
Vasculature: Veins and Arteries
Surface Anatomy-Lobes, gyri, Sulci
Histologic-Broadman’s
Functional-motor, sensory, speech
White Matter
Cross sectional imaging
Anterior circulation
Internal Carotid
Arteries
Posterior Circulation
Vertebral arteries
Superfcial and Deep Arterial Supply
to the Cerebral Hemispheres
Neuroradiology Modalities :
•
•
•
•
•
•
•
•
•
Plain Film
CT
US
MRI
Interventional
Angiography
Myelography
Biopsy
Nuclear Medicine
CT Basics
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
SIR GODFREY N. HOUNSFIELD
• 1979 Nobel Laureate
in Medicine
CT History
• 1972 – First clinical CT scanner
•
•
•
•
•
•
•
Used for head examinations
Water bath required
80 x 80 matrix
4 minutes per revolution
1 image per revolution
8 levels of grey
Overnight image reconstruction
CT History
• 2004 – 64 slice scanner
•
•
•
•
•
1024 x 1024 matrix
0.33s per revolution
64 images per revolution
0.4mm slice thickness
20 images reconstructed/second
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
CT Protocolling
• What happens when an exam is
requested?
• A requisiton is completed.
• The requested exam is protocolled according to
history, physical exam and previous exams.
• The patient information is confrmed.
• The exam is then performed.
• Images are ready to be interpreted in …
• Uncomplicated exam – 5-10 minutes after completion
• Complicated exams with reconstructions take at least 1
hour but usually 1-2 hours.
CT Protocolling
• CT head protocols
• With or Without contrast
• CT Brain
• CT Brain with posterior fossa images
• CT Angiogram/Venogram
• CT Perfusion
• CT of Sinuses
• CT of Orbit
• CT of Temporal bones
• CT of Mastoid bones
• CT of Skull
• CT of Face
CT Protocolling
• Variables
•
•
•
•
•
•
•
•
Plain or contrast enhanced
Slice positioning
Slice thickness
Slice orientation
Slice spacing and overlap
Timing of imaging and contrast administration
Reconstruction algorhithm
Radiation dosimetry
CT Protocolling
• Patient Information
• Is the patient pregnant?
• Radiation safety
• Can the patient cooperate for the exam?
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases (Stroke)
CT Terminology
• Exams using Ionizing radiation
• Plain flm
• CT
• 1/10 of all exams
• 2/3 OF RADIATION EXPOSURE
• Fluoroscopy
• Angiography, barium studies
• Nuclear medicine
• V/Q scan, bone scan
CT Terminology
• Attenuation
• Hyperattenuating (hyperdense)
• Hypoattenuating (hypodense)
• Isoattenuating (isodense)
• Attenuation is measured in Hounsfeld units
• Scale -1000 to 1000
• -1000 is air
• 0 is water
• 1000 is cortical bone
CT Terminology
• What we can see
• The brain is grey
•
•
•
•
White matter is usually dark grey (40)
Grey matter is usually light grey (45)
CSF is black (0)
Things that are brite on CT
•
•
•
•
•
Bone or calcifcation (>300)
Contrast
Hemorrhage (Acute ~ 70)
Hypercellular masses
Metallic foreign bodies
CT Terminology
• Voxel
• Volume element
• A voxel is the 2 dimensional representation of a 3
dimensional pixel (picture element).
• Partial volume averaging
CT Terminology
CT Terminology
• Window Width
• Number of Hounsfeld units from black to white
• Level or Center
• Hounsfeld unit approximating mid-gray
CT Terminology
CT Artifacts
CT Terminology
• Digital reading stations are the standard of care in
interpretation of CT and MRI.
• Why?
• Volume of images
• Ability to manipulate and reconstruct images
• Cost
CT Terminology
• DICOM
• Digital Imaging and Communications in Medicine
• DICOM provides standardized formats for images, a
common information model, application service
defnitions, and protocols for communication.
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Contrast
• Barium
• Iodinated
• vascular
• Biliary, Urinary
• CSF
• Gadolinium
Contrast
• Types of iodinated contrast
• Ionic
• Nonionic - standard of care
• No change in death rate from reaction but number
of reactions is decreased by factor of 4.
• If an enhanced study is needed, patient needs
to be NPO at least 4 hours and have no
contraindication to contrast, ie allergy or renal
insufciency.
Contrast
• What are the risks of iodinated contrast?
• Contrast reaction
• 1 in 10,000 have true anaphylactic reaction
• 1 in 100,000 to 1 in 1,000,000 will die
• Medical Issues
• Acute renal failure
• Lactic acidosis in diabetics
• If on Glucophage, patient must stop Glucophage for 48
hours after exam to prevent serious lactic acidosis
• Cardiac
• Extravasation
Contrast
• Who is at risk for an anaphylactic reaction?
• Patients with a prior history of contrast reaction
• Patients with a history asthma react at a rate of 1 in 2,000
• Patients with multiple environmental allergies, ie foods,
hay fever, medications
Amin MM, et al. Ionic and nonionic contrast media: Current status
and controversies.
Appl Radiol 1993; 22: 41-54.
Contrast
• Pretreatment for anaphylaxis
• 50 mg Oral Prednisone 13, 7 and 1 hour prior to exam
• 50 mg oral Benedryl 1 hour prior to exam
• In emergency, 200 mg iv hydrocortisone 2-4 hours prior to
exam
Contrast
• What are the risk factors for contrast induced
acute renal failure?
•
•
•
•
•
•
•
Pre-existing renal insufciency
Contrast volume
Dehydration
Advanced age
Drugs
Multiple myeloma
Cardiac failure
Contrast
• Considerations in patients with renal insufciency
• Is the exam necessary?
• Is there an alternative exam that can answer the
question?
• Decrease contrast dose
Contrast
• Pretreatment for renal insufciency
• Hydration
• Mucomyst
• 600 mg po BID the day before and day of study
Prevention of radiographic-contrast-agent-induced reductions in
renal function by acetylcysteine.
Tepel M, et al. N Engl J Med 2000 Jul 20;343(3):180-4
Contrast
• Contrast induced renal failure
• Elevated creatinine 24-48 hours after contrast which
resolves over 7-21 days.
• Can require dialysis
Mehran, R. et al. Radiocontrast induced renal failure:Allocations
and outcomes.
Reviews in Cardiovascular Medicine Vol. 2 Supp. 1 2001
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Radiation Safety
• Diagnostic CT Scans: Assessment of Patient,
Physician, and Radiologist Awareness of Radiation
Dose and Possible Risks
• Lee, C. et al. Radiology 2004;231:393
Radiation Safety
• Deterministic Efects
• Have a threshold below which no efect will be seen.
• Stochastic Efects
• Have no threshold and the efects are based on the dose x
quality factor.
Radiation Safety
• Terminology
• Gy = Gray is the absorbed dose (SI unit)
• The equivalent of 1 joule/kg of tissue
• Rad = radiation absorbed dose
• Sv = Sievert is the dose equivalent (SI unit)
• Absorbed dose multiplied by a quality factor
• Rem = radiation equivalent man
Radiation Safety
• Relative values of CT exam exposure
• Background radiation is 3 mSv/year
• Water, food, air, solar
• In Denver (altitude 5280 ft.) 10 mSv/year
• CXR = 0.1 mSv
• CT head = 2 mSv
• CT Chest = 8 mSv
• CT Abdomen and Pelvis = 20 mSv
-The equivalent of 200 CXR
Radiation Safety
•
Efects of X rays.
•
•
Absorption of photons by biological material leads
to breakage of chemical bonds.
The principal biological efect results from
damage to DNA caused by either the direct or
indirect action of radiation.
Radiation Safety
•
Tissue/Organ radiosensitivity
•
•
•
•
•
•
Fetal cells
Lymphoid and hematopoietic tissues; intestinal
epithelium
Epidermal, esophageal, oropharyngeal epithelia
Interstitial connective tissue, fne vasculature
Renal, hepatic, and pancreatic tissue
Muscle and neuronal tissue
Radiation Safety
• Estimated Risks of Radiation-Induced
Fatal Cancer from Pediatric CT
• David J. Brenner, et al. AJR 2001; 176:289296
• Additional 170 cancer deaths for each year of
head CT in the US.
• 140,000 total cancer deaths, therefore ~ 0.12%
increase
• 1 in 1500 will die from radiologically induced cancer
Radiation Safety
• 3094 men received radiation for hemangioma
• Those receiving >100 mGy
• Decreased high school attendance
• Lower cognitive test scores
Per Hall, et al. Effect off loe doses off ioiisiig radiatioi ii iiffaicy oi
cogiitive ffuictioi ii adulthood: Seedish populatioi based cohort
study
Radiation Safety
•
Hiroshima and Nagasaki
•
There has been no detectable increase in genetic
defects related to radiation in a large sample
(80,000) of survivor ofspring, including: congenital
abnormalities, mortality (including childhood
cancers), chromosome aberrations, or mutations in
biochemically identifable genes.
William J Schull, Effects off Aetocic Radiatioi: Ae H alff-CCeitury off
Studies ffroc H iroshica aid Nagasaki, 1995.
Radiation Safety
• Hiroshima and Nagasaki
• However, exposed individuals who survived the acute
efects were later found to sufer increased incidence of
cancer of essentially all organs.
William J Schull, Effects off Aetocic Radiatioi: Ae H alff-CCeitury off
Studies ffroc H iroshica aid Nagasaki, 1995.
Radiation Safety
• Hiroshima and Nagasaki
• Most victims with high doses died
• Victims with low doses despite their large numbers are
still statistically insignifcant.
Radiation Safety
Comparison of Image Quality
Between Conventional and LowDose Nonenhanced Head CT
Mark E. Mullinsa, et al.
AJNR April 2004.
Reduction of mAs from 170 to 90
Radiation Safety
• What does all this mean?
• 1 CXR approximates the same risk as:
• 1 year watching TV (CRT)
• 1 coast to coast airplane fight
• 3 pufs on a cigarette
• 2 days living in Denver
• 1 Head CT is approximately 20 CXR
Health Physics Society on the web--http://hps.org
Radiation Safety
• The pregnant patient
• Can another exam answer the question?
• What is the gestational age?
• Counsel the patient
• 3% of all deliveries have some type of spontaneous
abnormality
• The mother’s health is the primary concern.
Radiation Safety
• "No single diagnostic procedure results in a
radiation dose that threatens the well-being of the
developing embryo and fetus." -- American College of
Radiology
• "Women should be counseled that x-ray exposure
from a single diagnostic procedure does not result
in harmful fetal efects. Specifcally, exposure to
less than 5 rad has not been associated with an
increase in fetal anomalies or pregnancy loss." -American College of Obstetricians and Gynecologists
Conclusion
• CT Terminology
• Attenuation (density) in Hounsfeld units
• Digital interpretation is standard of care
• CT has risks
• Contrast
• Radiation exposure
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Normal
CT
1 day
1 year
2 years
Normal CT
Older person
Normal CT
Older
Person
Normal Enhanced CT
NEURORADIOLO
GY
Sianny Suryawati
Radiology Department, Faculty of Medicine
Wijaya Kusuma University, Surabaya
2015
Outline
•
•
•
•
•
Normal Imaging Anatomy of Brain
Basic Features of Brain Lesions
Brain Tumor
Cerebrovascular Disease
Traumatic Brain Injury
Normal Imaging Anatomy of
Brain
•
•
•
•
•
•
•
Skull and Meninges (Dura, Pia)
Vasculature: Veins and Arteries
Surface Anatomy-Lobes, gyri, Sulci
Histologic-Broadman’s
Functional-motor, sensory, speech
White Matter
Cross sectional imaging
Anterior circulation
Internal Carotid
Arteries
Posterior Circulation
Vertebral arteries
Superfcial and Deep Arterial Supply
to the Cerebral Hemispheres
Neuroradiology Modalities :
•
•
•
•
•
•
•
•
•
Plain Film
CT
US
MRI
Interventional
Angiography
Myelography
Biopsy
Nuclear Medicine
CT Basics
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
SIR GODFREY N. HOUNSFIELD
• 1979 Nobel Laureate
in Medicine
CT History
• 1972 – First clinical CT scanner
•
•
•
•
•
•
•
Used for head examinations
Water bath required
80 x 80 matrix
4 minutes per revolution
1 image per revolution
8 levels of grey
Overnight image reconstruction
CT History
• 2004 – 64 slice scanner
•
•
•
•
•
1024 x 1024 matrix
0.33s per revolution
64 images per revolution
0.4mm slice thickness
20 images reconstructed/second
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
CT Protocolling
• What happens when an exam is
requested?
• A requisiton is completed.
• The requested exam is protocolled according to
history, physical exam and previous exams.
• The patient information is confrmed.
• The exam is then performed.
• Images are ready to be interpreted in …
• Uncomplicated exam – 5-10 minutes after completion
• Complicated exams with reconstructions take at least 1
hour but usually 1-2 hours.
CT Protocolling
• CT head protocols
• With or Without contrast
• CT Brain
• CT Brain with posterior fossa images
• CT Angiogram/Venogram
• CT Perfusion
• CT of Sinuses
• CT of Orbit
• CT of Temporal bones
• CT of Mastoid bones
• CT of Skull
• CT of Face
CT Protocolling
• Variables
•
•
•
•
•
•
•
•
Plain or contrast enhanced
Slice positioning
Slice thickness
Slice orientation
Slice spacing and overlap
Timing of imaging and contrast administration
Reconstruction algorhithm
Radiation dosimetry
CT Protocolling
• Patient Information
• Is the patient pregnant?
• Radiation safety
• Can the patient cooperate for the exam?
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases (Stroke)
CT Terminology
• Exams using Ionizing radiation
• Plain flm
• CT
• 1/10 of all exams
• 2/3 OF RADIATION EXPOSURE
• Fluoroscopy
• Angiography, barium studies
• Nuclear medicine
• V/Q scan, bone scan
CT Terminology
• Attenuation
• Hyperattenuating (hyperdense)
• Hypoattenuating (hypodense)
• Isoattenuating (isodense)
• Attenuation is measured in Hounsfeld units
• Scale -1000 to 1000
• -1000 is air
• 0 is water
• 1000 is cortical bone
CT Terminology
• What we can see
• The brain is grey
•
•
•
•
White matter is usually dark grey (40)
Grey matter is usually light grey (45)
CSF is black (0)
Things that are brite on CT
•
•
•
•
•
Bone or calcifcation (>300)
Contrast
Hemorrhage (Acute ~ 70)
Hypercellular masses
Metallic foreign bodies
CT Terminology
• Voxel
• Volume element
• A voxel is the 2 dimensional representation of a 3
dimensional pixel (picture element).
• Partial volume averaging
CT Terminology
CT Terminology
• Window Width
• Number of Hounsfeld units from black to white
• Level or Center
• Hounsfeld unit approximating mid-gray
CT Terminology
CT Artifacts
CT Terminology
• Digital reading stations are the standard of care in
interpretation of CT and MRI.
• Why?
• Volume of images
• Ability to manipulate and reconstruct images
• Cost
CT Terminology
• DICOM
• Digital Imaging and Communications in Medicine
• DICOM provides standardized formats for images, a
common information model, application service
defnitions, and protocols for communication.
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Contrast
• Barium
• Iodinated
• vascular
• Biliary, Urinary
• CSF
• Gadolinium
Contrast
• Types of iodinated contrast
• Ionic
• Nonionic - standard of care
• No change in death rate from reaction but number
of reactions is decreased by factor of 4.
• If an enhanced study is needed, patient needs
to be NPO at least 4 hours and have no
contraindication to contrast, ie allergy or renal
insufciency.
Contrast
• What are the risks of iodinated contrast?
• Contrast reaction
• 1 in 10,000 have true anaphylactic reaction
• 1 in 100,000 to 1 in 1,000,000 will die
• Medical Issues
• Acute renal failure
• Lactic acidosis in diabetics
• If on Glucophage, patient must stop Glucophage for 48
hours after exam to prevent serious lactic acidosis
• Cardiac
• Extravasation
Contrast
• Who is at risk for an anaphylactic reaction?
• Patients with a prior history of contrast reaction
• Patients with a history asthma react at a rate of 1 in 2,000
• Patients with multiple environmental allergies, ie foods,
hay fever, medications
Amin MM, et al. Ionic and nonionic contrast media: Current status
and controversies.
Appl Radiol 1993; 22: 41-54.
Contrast
• Pretreatment for anaphylaxis
• 50 mg Oral Prednisone 13, 7 and 1 hour prior to exam
• 50 mg oral Benedryl 1 hour prior to exam
• In emergency, 200 mg iv hydrocortisone 2-4 hours prior to
exam
Contrast
• What are the risk factors for contrast induced
acute renal failure?
•
•
•
•
•
•
•
Pre-existing renal insufciency
Contrast volume
Dehydration
Advanced age
Drugs
Multiple myeloma
Cardiac failure
Contrast
• Considerations in patients with renal insufciency
• Is the exam necessary?
• Is there an alternative exam that can answer the
question?
• Decrease contrast dose
Contrast
• Pretreatment for renal insufciency
• Hydration
• Mucomyst
• 600 mg po BID the day before and day of study
Prevention of radiographic-contrast-agent-induced reductions in
renal function by acetylcysteine.
Tepel M, et al. N Engl J Med 2000 Jul 20;343(3):180-4
Contrast
• Contrast induced renal failure
• Elevated creatinine 24-48 hours after contrast which
resolves over 7-21 days.
• Can require dialysis
Mehran, R. et al. Radiocontrast induced renal failure:Allocations
and outcomes.
Reviews in Cardiovascular Medicine Vol. 2 Supp. 1 2001
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Radiation Safety
• Diagnostic CT Scans: Assessment of Patient,
Physician, and Radiologist Awareness of Radiation
Dose and Possible Risks
• Lee, C. et al. Radiology 2004;231:393
Radiation Safety
• Deterministic Efects
• Have a threshold below which no efect will be seen.
• Stochastic Efects
• Have no threshold and the efects are based on the dose x
quality factor.
Radiation Safety
• Terminology
• Gy = Gray is the absorbed dose (SI unit)
• The equivalent of 1 joule/kg of tissue
• Rad = radiation absorbed dose
• Sv = Sievert is the dose equivalent (SI unit)
• Absorbed dose multiplied by a quality factor
• Rem = radiation equivalent man
Radiation Safety
• Relative values of CT exam exposure
• Background radiation is 3 mSv/year
• Water, food, air, solar
• In Denver (altitude 5280 ft.) 10 mSv/year
• CXR = 0.1 mSv
• CT head = 2 mSv
• CT Chest = 8 mSv
• CT Abdomen and Pelvis = 20 mSv
-The equivalent of 200 CXR
Radiation Safety
•
Efects of X rays.
•
•
Absorption of photons by biological material leads
to breakage of chemical bonds.
The principal biological efect results from
damage to DNA caused by either the direct or
indirect action of radiation.
Radiation Safety
•
Tissue/Organ radiosensitivity
•
•
•
•
•
•
Fetal cells
Lymphoid and hematopoietic tissues; intestinal
epithelium
Epidermal, esophageal, oropharyngeal epithelia
Interstitial connective tissue, fne vasculature
Renal, hepatic, and pancreatic tissue
Muscle and neuronal tissue
Radiation Safety
• Estimated Risks of Radiation-Induced
Fatal Cancer from Pediatric CT
• David J. Brenner, et al. AJR 2001; 176:289296
• Additional 170 cancer deaths for each year of
head CT in the US.
• 140,000 total cancer deaths, therefore ~ 0.12%
increase
• 1 in 1500 will die from radiologically induced cancer
Radiation Safety
• 3094 men received radiation for hemangioma
• Those receiving >100 mGy
• Decreased high school attendance
• Lower cognitive test scores
Per Hall, et al. Effect off loe doses off ioiisiig radiatioi ii iiffaicy oi
cogiitive ffuictioi ii adulthood: Seedish populatioi based cohort
study
Radiation Safety
•
Hiroshima and Nagasaki
•
There has been no detectable increase in genetic
defects related to radiation in a large sample
(80,000) of survivor ofspring, including: congenital
abnormalities, mortality (including childhood
cancers), chromosome aberrations, or mutations in
biochemically identifable genes.
William J Schull, Effects off Aetocic Radiatioi: Ae H alff-CCeitury off
Studies ffroc H iroshica aid Nagasaki, 1995.
Radiation Safety
• Hiroshima and Nagasaki
• However, exposed individuals who survived the acute
efects were later found to sufer increased incidence of
cancer of essentially all organs.
William J Schull, Effects off Aetocic Radiatioi: Ae H alff-CCeitury off
Studies ffroc H iroshica aid Nagasaki, 1995.
Radiation Safety
• Hiroshima and Nagasaki
• Most victims with high doses died
• Victims with low doses despite their large numbers are
still statistically insignifcant.
Radiation Safety
Comparison of Image Quality
Between Conventional and LowDose Nonenhanced Head CT
Mark E. Mullinsa, et al.
AJNR April 2004.
Reduction of mAs from 170 to 90
Radiation Safety
• What does all this mean?
• 1 CXR approximates the same risk as:
• 1 year watching TV (CRT)
• 1 coast to coast airplane fight
• 3 pufs on a cigarette
• 2 days living in Denver
• 1 Head CT is approximately 20 CXR
Health Physics Society on the web--http://hps.org
Radiation Safety
• The pregnant patient
• Can another exam answer the question?
• What is the gestational age?
• Counsel the patient
• 3% of all deliveries have some type of spontaneous
abnormality
• The mother’s health is the primary concern.
Radiation Safety
• "No single diagnostic procedure results in a
radiation dose that threatens the well-being of the
developing embryo and fetus." -- American College of
Radiology
• "Women should be counseled that x-ray exposure
from a single diagnostic procedure does not result
in harmful fetal efects. Specifcally, exposure to
less than 5 rad has not been associated with an
increase in fetal anomalies or pregnancy loss." -American College of Obstetricians and Gynecologists
Conclusion
• CT Terminology
• Attenuation (density) in Hounsfeld units
• Digital interpretation is standard of care
• CT has risks
• Contrast
• Radiation exposure
CT Basics
• Neuroradiology
• The BASICS of CT
•
•
•
•
•
•
CT History
Protocol
Terminology
Contrast
Radiation Safety
Cases
Normal
CT
1 day
1 year
2 years
Normal CT
Older person
Normal CT
Older
Person
Normal Enhanced CT