specializzazione radio.ppt

Introduction to Introduction to Neuroimaging Neuroimaging

Stefano Bastianello MD, PhDStefano Bastianello MD, PhD

Full Professor of NeuroradiologyFull Professor of Neuroradiology

University of PaviaUniversity of Pavia

updated 29 March 2013

NeuroradiologistNeuroradiologist

A A consultantconsultant in imaging and disease of in imaging and disease of the brain, spinal cord, head, neck, face the brain, spinal cord, head, neck, face and peripheral nervesand peripheral nerves

NeuroradiologyNeuroradiology

Plain FilmPlain Film CTCT USUS MRIMRI InterventionalInterventional

AngiographyAngiographyMyelographyMyelographyBiopsyBiopsy

Nuclear MedicineNuclear Medicine


A request for an exam is a consultationA request for an exam is a consultationHistoryHistoryPertinent physical exam findingsPertinent physical exam findings

• Lab resultsLab resultsCreatinineCreatininePT/INRPT/INR

What is the question?What is the question?

Q: What is radiology?Q: What is radiology?

Answer (from Wikipedia):Answer (from Wikipedia): Radiology is the branch of medical science dealing with the medical use of radiation devices and other forms of energy for the purpose of obtaining visual information as part of medical imaging. Interventional radiology is the performance of medical procedures with the help of medical imaging.

What is a neuroradiologist?What is a neuroradiologist?

A neuroradiologist is a radiologist who specializes in the use of x-rays and other scanning devices for the diagnosis and treatment of diseases of the nervous system.

A neuroradiologist must be concerned with the clinical imaging, therapy, and basic science of the central and peripheral nervous system, including but not limited to the brain, spine, head and neck.

Goals/ObjectivesGoals/Objectives

Review basic anatomic landmarks in the Review basic anatomic landmarks in the brainbrain

Learn the three different orientations Learn the three different orientations neuroradiologists use to view images of neuroradiologists use to view images of the brainthe brain

Be able to distinguish between a CT scan, Be able to distinguish between a CT scan, T1-weighted MR image, and a T2-T1-weighted MR image, and a T2-weighted MR image of the brainweighted MR image of the brain

OrientationOrientation

Sagittal PlaneSagittal Plane

Coronal PlaneCoronal Plane

Axial (Transverse) PlaneAxial (Transverse) Plane

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IntroductionIntroduction

Knowledge of the basic neuro-anatomy is Knowledge of the basic neuro-anatomy is essential to establish the diagnosis.essential to establish the diagnosis.

Several imaging modalities are currently Several imaging modalities are currently available to evaluate CNS disorders.available to evaluate CNS disorders.

Its important for physicians to be able to Its important for physicians to be able to request the correct radiological study request the correct radiological study depending on the symptoms and suspected depending on the symptoms and suspected diagnosis.diagnosis.

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Imaging ModalitiesImaging Modalities

Plain film.Plain film.Computerized radiography(CT).Computerized radiography(CT).Magnetic resonance imaging(MRI).Magnetic resonance imaging(MRI).Myelogram.Myelogram.Angiogram.Angiogram.Ultrasound.Ultrasound.

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Plain X RayPlain X Ray

Plain X-ray is essential modality for initial Plain X-ray is essential modality for initial assessment of the spine.assessment of the spine.

Good display of bony detailsGood display of bony details Skull X ray is of limited value in evaluation of head Skull X ray is of limited value in evaluation of head

trauma since it may not reflect underlying CNS trauma since it may not reflect underlying CNS damage.damage.

However, skull X ray helps in classification of skull However, skull X ray helps in classification of skull fractures and its extent and therefore further fractures and its extent and therefore further management.management.

Radiography (X-Ray)Radiography (X-Ray)

Radiography (X-Ray)Radiography (X-Ray)

Primarily used for spine:Primarily used for spine:

• TraumaTrauma

• Degenerative DzDegenerative Dz

• Post-opPost-op

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Computerized TomographyComputerized TomographyCTCT

Readily available fast modality for evaluation Readily available fast modality for evaluation of intracranial structures.of intracranial structures.

Rapid acquisition of axial images.Rapid acquisition of axial images.The procedure of choice for evaluation of The procedure of choice for evaluation of

patients with head trauma and stroke patients.patients with head trauma and stroke patients.Provides fine details of the bony structures.Provides fine details of the bony structures.

CT BasicsCT Basics

CT BasicsCT BasicsNeuroradiologyNeuroradiologyThe The BASICSBASICS of CT of CT

CT HistoryCT HistoryProtocolProtocolTerminologyTerminologyContrastContrastRadiation SafetyRadiation SafetyCases Cases

CT HistoryCT History

SIR GODFREY N. HOUNSFIELDSIR GODFREY N. HOUNSFIELD 1979 Nobel 1979 Nobel

Laureate in Laureate in MedicineMedicine


1972 – First clinical CT scanner1972 – First clinical CT scannerUsed for head examinationsUsed for head examinationsWater bath requiredWater bath required80 x 80 matrix80 x 80 matrix4 minutes per revolution4 minutes per revolution1 image per revolution1 image per revolution8 levels of grey8 levels of greyOvernight image reconstructionOvernight image reconstruction


2004 – 64 slice scanner2004 – 64 slice scanner0.33s per revolution0.33s per revolution

2013 – 640 slice scanner2013 – 640 slice scanner0.27s per revolution0.27s per revolutionLow dose Xrays !Low dose Xrays !

CT ProtocollingCT Protocolling

CT head protocolsCT head protocolsWith or Without contrastWith or Without contrastCT BrainCT BrainCT Brain with posterior fossa imagesCT Brain with posterior fossa imagesCT Angiogram/Venogram CT Angiogram/Venogram CT PerfusionCT PerfusionCT of SinusesCT of SinusesCT of OrbitCT of OrbitCT of Temporal bonesCT of Temporal bonesCT of Mastoid bonesCT of Mastoid bonesCT of SkullCT of SkullCT of FaceCT of Face


VariablesVariablesPlain or contrast enhancedPlain or contrast enhancedSlice positioningSlice positioningSlice thicknessSlice thicknessSlice orientationSlice orientationSlice spacing and overlapSlice spacing and overlapTiming of imaging and contrast administrationTiming of imaging and contrast administrationReconstruction algorhithmReconstruction algorhithmRadiation dosimetryRadiation dosimetry


Patient InformationPatient InformationIs the patient pregnant?Is the patient pregnant?

• Radiation safetyRadiation safetyCan the patient cooperate for the exam?Can the patient cooperate for the exam?

CT TerminologyCT Terminology

Exams using Exams using Ionizing radiationIonizing radiation Plain filmPlain filmCTCT

• 1/10 of all exams1/10 of all exams• 2/3 OF RADIATION EXPOSURE2/3 OF RADIATION EXPOSURE

FluoroscopyFluoroscopy• Angiography, barium studiesAngiography, barium studies

Nuclear medicineNuclear medicine• V/Q scan, bone scanV/Q scan, bone scan

What is a CT (or CAT) scan?What is a CT (or CAT) scan?

CT stands for CT stands for “computed “computed tomography” - this is tomography” - this is a complex machine a complex machine that uses x-rays to that uses x-rays to create three-create three-dimensional images dimensional images of the bodyof the body

Computed Tomography (CT)Computed Tomography (CT)

What is bright/dark on CT?What is bright/dark on CT?

The more dense the The more dense the tissue, the brighter it tissue, the brighter it looks on CTlooks on CT

Any calcified structure Any calcified structure (like the skull) (like the skull) appears bright appears bright

New hemorrhage in New hemorrhage in the brain is also brightthe brain is also bright

Water (or CSF) looks Water (or CSF) looks dark on CTdark on CT

Computed TomographyComputed Tomography

A CT image is a pixel-by-pixel map ofA CT image is a pixel-by-pixel map of X-ray beam X-ray beam attenuationattenuation

(essentially(essentially densitydensity)) inin Hounsfield Units (HU)Hounsfield Units (HU)

HUHUwaterwater = 0 = 0

Bright = Bright = ““hyper-attenuatinghyper-attenuating”” or or ““hyper-densehyper-dense””

CT TerminologyCT Terminology

AttenuationAttenuationHyperattenuating (hyperdense)Hyperattenuating (hyperdense)Hypoattenuating (hypodense)Hypoattenuating (hypodense)Isoattenuating (isodense)Isoattenuating (isodense)

Attenuation is measured in Hounsfield Attenuation is measured in Hounsfield unitsunitsScale -1000 to 1000Scale -1000 to 1000

• -1000 is air-1000 is air• 0 is water0 is water• 1000 is cortical bone1000 is cortical bone


Typical HU Values:Typical HU Values:

AirAir –1000–1000

FatFat –100 to –40–100 to –40

WaterWater 00

Other fluids Other fluids (e.g. CSF)(e.g. CSF) 0–200–20

White matterWhite matter 20–3520–35

Gray matterGray matter 30–4030–40

Blood clotBlood clot 55–7555–75

CalcificationCalcification >150>150

BoneBone 10001000

Metallic foreign bodyMetallic foreign body >1000>1000

BrainBrain


Attenuation: High or Low?Attenuation: High or Low?

High:High:

1.1. Blood, calciumBlood, calcium

2.2. Less fluid / more Less fluid / more tissuetissue

Low:Low:

1.1. Fat, air Fat, air

2.2. More fluid / less More fluid / less tissuetissue

AirAir –1000–1000

FatFat –100 to –40–100 to –40

WaterWater 00

Other fluidsOther fluids 0–200–20

White matterWhite matter 20–3520–35

Gray matterGray matter 30–4030–40

Blood clotBlood clot 55–7555–75

CalcificationCalcification >150>150

BoneBone 10001000

Metallic foreign bodyMetallic foreign body >1000>1000


““Soft Tissue Window” “Bone Window”Soft Tissue Window” “Bone Window”


Scan axially…Scan axially………stack and stack and re-slicere-slice in any in any

planeplane““2D Recons2D Recons””

CT IndicationsCT Indications• Skull and skull base, vertebraeSkull and skull base, vertebrae

(trauma, bone lesions)(trauma, bone lesions)

• VentriclesVentricles

(hydrocephalus, shunt placement)(hydrocephalus, shunt placement)

• Intracranial masses, mass effectsIntracranial masses, mass effects

(headache, N/V, visual symptoms, etc.)(headache, N/V, visual symptoms, etc.)

• Hemorrhage, ischemiaHemorrhage, ischemia

(stroke, mental status change)(stroke, mental status change)

• CalcificationCalcification

(lesion characterization)(lesion characterization)

Skull and skull base, vertebraeSkull and skull base, vertebrae

FracturesFractures

Skull and skull base, vertebraeSkull and skull base, vertebrae

Multiple Myeloma OsteomaMultiple Myeloma Osteoma

VentriclesVentricles

HydrocephalusHydrocephalus

Intracranial masses, mass effectsIntracranial masses, mass effects

Solid mass Cystic massSolid mass Cystic mass

Intracranial masses, mass effectsIntracranial masses, mass effects

L hemisphere swelling Generalized swellingL hemisphere swelling Generalized swelling

Acute HemorrhageAcute Hemorrhage

Intraparenchymal Subarachnoid Subdural EpiduralIntraparenchymal Subarachnoid Subdural Epidural

Acute IschemiaAcute Ischemia

Loss of gray-white distinction and swelling in known arterial territoryLoss of gray-white distinction and swelling in known arterial territory

CalcificationCalcification

HyperparathyroidismHyperparathyroidism

1.1. Rapid IV contrast bolusRapid IV contrast bolus

1.1. Dynamic scanning during Dynamic scanning during arterial phasearterial phase

2.2. Advanced 2D and 3D Reconstructions:Advanced 2D and 3D Reconstructions: 2D multi-planar (sagittal, coronal)2D multi-planar (sagittal, coronal) Volume–rendered 3D reconsVolume–rendered 3D recons

CT AngiographyCT Angiography

CT Angiography - HeadCT Angiography - Head

CT Angiography - HeadCT Angiography - HeadCircle of WillisCircle of Willis

AneurysmsAneurysms

Vascular MalformationsVascular Malformations

CT Angiography - NeckCT Angiography - Neck

CarotidCarotid

bifurcationsbifurcations

Vertebral Vertebral arteriesarteries

Aortic archAortic arch

CT AngiographyCT Angiography3D Volume Rendering3D Volume Rendering

What is MR?What is MR?

MR stands for MR stands for “magnetic resonance” “magnetic resonance” - this is a tool that - this is a tool that uses magnetic fields uses magnetic fields created by a giant created by a giant magnet to produce magnet to produce three-dimensional three-dimensional images of the human images of the human bodybody

MAGNETIC RESONANCE IMAGINGMAGNETIC RESONANCE IMAGING

AdvantagesAdvantages

1.1. Multiple signal sources Multiple signal sources 2.2. No iodine toxicity/allergy issuesNo iodine toxicity/allergy issues3.3. No ionizing radiation issuesNo ionizing radiation issues

MRI Safety: The Magnet is MRI Safety: The Magnet is Always OnAlways On!!

Magnetic Resonance SafetyMagnetic Resonance Safety

Typically safe*:Typically safe*:• Orthopedic hardwareOrthopedic hardware

• Surgical clips, staples, Surgical clips, staples, sutures (older devices must be sutures (older devices must be checked!)checked!)

• Intravascular stents/filtersIntravascular stents/filters

* This is an incomplete list and there are many exceptions to every * This is an incomplete list and there are many exceptions to every ““rulerule”” When in doubt, check it out!When in doubt, check it out!

Typically unsafe*:Typically unsafe*:• Cardiac pacemakers Cardiac pacemakers

(and other electrical devices) (and other electrical devices)

• Some older aneurysm clipsSome older aneurysm clips

• Metal fragments in orbit Metal fragments in orbit

(1 case report)(1 case report)

• Oxygen tanks, carts, chairs, Oxygen tanks, carts, chairs, stools, IV poles, gurneys, etc.stools, IV poles, gurneys, etc.

• Some cosmetics, tattoos, jewelry, Some cosmetics, tattoos, jewelry, hairpins, etc.hairpins, etc.

• Pager, watch, wallet, ID badge, Pager, watch, wallet, ID badge, pen, keys, pocketknife, etc.pen, keys, pocketknife, etc.

MRI Safety Test:MRI Safety Test:

Will it: Move? Torque? Get hot? Pass a current? Malfunction? Will it: Move? Torque? Get hot? Pass a current? Malfunction? Become a projectile? Become a projectile? Get stuck in scanner? Get stuck in scanner?

MAGNETIC RESONANCE IMAGINGMAGNETIC RESONANCE IMAGING

LimitationsLimitations1. ICU patients and Claustrophobia1. ICU patients and Claustrophobia2. Metal artifact 2. Metal artifact

1. RF Energy – pacemaker override

2. Magnetic field - aneurysm clips - ocular metal -missile effect3. Nephrogenic Systemic Fibrosis- gadolinium toxicity in renal failure

superconducting magnet creates the stong magnetic field that aligns the protons.

The radio frequency coil is a transmission and receiver coil to excite the sample tissue with radio frequency pulse and pick up the emitted signal once the excitatory pulse has terminated.

the Gradient power adjusts the magnetic field to specific areas and the computer work station collects and displays the data.

COMPUTERCOMPUTER

Magnetic Resonance ImagingMagnetic Resonance Imaging

magnetic magnetic fieldfield

RFRF

TransmitterTransmitter ReceiverReceiver

RF = RF = RRadio adio FFrequency energyrequency energy

Received Received signalsignal

RF

This is a diagram of a patient within the magnetic field with the protons aligned in the field and showing the RF pulse being transmitted into the sample.

The RF pulse disturbs the alignment of the protons and this then causes the protons to resonate and emit an RF pulse which is the source of the signal.

Magnetic Resonance (MR)Magnetic Resonance (MR)

Hydrogen proton in Hydrogen proton in water or fatwater or fat

MRIMRI

MR HAS ADVANTAGE OF

MULTI PLANAR IMAGING

MRI INDICATIONSMRI INDICATIONS

IschemiaIschemiaTumorTumor InfectionInfectionDating blood productsDating blood productsCongenital abnormalitiesCongenital abnormalities

MR INTERPRETATIONMR INTERPRETATION

SymmetrySymmetry Identify normal structuresIdentify normal structures

VentriclesVentriclesGrey matter structuresGrey matter structuresWhite matter tractsWhite matter tracts

NO DENSITY SCALE – Intensity/ SignalNO DENSITY SCALE – Intensity/ SignalDescription of tissue signal on various different scanning Description of tissue signal on various different scanning

sequences ie. T1 T2 Flair Diffusion Gadoliniumsequences ie. T1 T2 Flair Diffusion Gadolinium

Magnetic Resonance ImagingMagnetic Resonance Imaging

Magnetic ResonanceMagnetic Resonance

Tissue contrast in MR may be based on:Tissue contrast in MR may be based on:

• Proton densityProton density

• Water/fat/protein contentWater/fat/protein content

• Metabolic compounds (MR Spectroscopy)Metabolic compounds (MR Spectroscopy)

e.g. Choline, creatine, N-acetylaspartate, lactatee.g. Choline, creatine, N-acetylaspartate, lactate

• Magnetic properties of specific moleculesMagnetic properties of specific molecules

e.g.e.g. HemoglobinHemoglobin

• Diffusion of waterDiffusion of water

• Perfusion (capillary blood flow)Perfusion (capillary blood flow)

• Bulk flow (large vessels, CSF)Bulk flow (large vessels, CSF)

Magnetic ResonanceMagnetic ResonanceExcited protons Excited protons relax relax back to equilibriumback to equilibrium

Tissues have intrinsic parameters classed as T1 and T2 values which describe how the tissue responds to the MR signal

T1T1

T2T2

T1 SCANT1 SCAN T2 SCAN

MR SIGNAL

The T1 identifies how quickly a tissue recovers and realigns in

the magnetic field after the radio pulse ends

The T2 identifies how long a tissue resonates after a

pulse T1 and T2 are characteristic of tissues They function as the basis for the imaging sequence

MRI INTERPRETATIONMRI INTERPRETATION

Pulse SequencesPulse SequencesVarying the pulse time/delay/repetition gives an image with varying T1

and T2 effects.

− T1 weighted T1 weighted (Fat, Melanin, Hemosiderin, Methemoglobin= bright)(Fat, Melanin, Hemosiderin, Methemoglobin= bright)

− T2 weighted T2 weighted (Water, Oxyhemoglobin, Hemosiderin= bright)(Water, Oxyhemoglobin, Hemosiderin= bright) − FLAIR FLAIR (Pathology bright, CSF dark)(Pathology bright, CSF dark)

− Diffusion Weighted- Diffusion Weighted- recent infarction brightrecent infarction bright

The two most common types The two most common types of MR images are…of MR images are…

T1-weighted MR imagesT1-weighted MR images- - useful to look at normal useful to look at normal anatomyanatomy of the brain of the brain

T2-weight MR imagesT2-weight MR images - - useful to look at abnormal useful to look at abnormal processes (or processes (or pathologypathology) ) in the brainin the brain

What is bright/dark on T1?What is bright/dark on T1?

Fat is brightFat is bright White matter (inner White matter (inner

part of brain) is part of brain) is brighter than gray brighter than gray matter (cortex or matter (cortex or outer part of the outer part of the brain)brain)

Water (CSF) is darkWater (CSF) is dark

What is bright/dark on T2?What is bright/dark on T2?

Water is brightWater is bright

White matter is darker White matter is darker than gray matterthan gray matter

T1 SCAN

T2 SCAN

Anatomic structuresFat = brightWater = hypo intense

Water weighted sequenceWater = brightFat = relatively hypointenseGood for identifying pathology

““T1-weighted”T1-weighted” ““T2-weighted” T2-weighted” w/ fat suppressionw/ fat suppression



Arachnoid CystArachnoid Cyst

T2T2T1T1


T2 T2 w/ water suppressionT2 T2 w/ water suppression(T2-FLAIR)(T2-FLAIR)


T2T2 T2*T2*

Accentuating blood/calciumAccentuating blood/calcium

““blooming”blooming”

NORMALNORMAL CYTOTOXIC EDEMA CYTOTOXIC EDEMA (Acute Ischemia)(Acute Ischemia)

Diffusion Diffusion

MR Signal MR Signal

Diffusion MR ImagingDiffusion MR Imaging

Magnetic ResonanceMagnetic ResonanceImaging DiffusionImaging Diffusion

Highly sensitive to acute Highly sensitive to acute ischemia—ischemia—

+ within a few hours!+ within a few hours!

No other imaging is more No other imaging is more sensitive to acute ischemiasensitive to acute ischemia

Acute left MCA infarctionAcute left MCA infarction

DWIDWI

Magnetic Resonance AngiographyMagnetic Resonance Angiography

Axial Axial ““sourcesource”” images… images… ……reformatted to reformatted to ““maximum intensity maximum intensity projectionsprojections”” (MIP) (MIP)

Multiple projections allow 3D-like Multiple projections allow 3D-like displaydisplayNo need for IV contrast!No need for IV contrast!

MRA MRA Perfusion MR Perfusion MR

Magnetic Resonance Angiography with Perfusion Magnetic Resonance Angiography with Perfusion MRMR

perfusionperfusion imaging reveals hypoperfused imaging reveals hypoperfused

tissue tissue at riskat risk for ischemia for ischemia

1.1. CT: CT: IodineIodine-based-based

Iodine is highly attenuating of X-ray beam (Iodine is highly attenuating of X-ray beam (bright on CTbright on CT))

MRI: MRI: GadoliniumGadolinium-based-based

Gadolinium is a paramagnetic metal that hastens T1 relaxation of nearby Gadolinium is a paramagnetic metal that hastens T1 relaxation of nearby water protons (water protons (bright on T1-weighted imagesbright on T1-weighted images))

1.1. Tissue that gets Tissue that gets brighterbrighter with IV contrast is said to “ with IV contrast is said to “enhanceenhance” (Brightness, in ” (Brightness, in and of itself, is and of itself, is notnot enhancement!) enhancement!)

• Enhancement reflects the vascularity of tissue, but…Enhancement reflects the vascularity of tissue, but…

The The blood-brain barrierblood-brain barrier keeps IV contrast outkeeps IV contrast out of the brainof the brain! !

Enhancement implies BBB is Enhancement implies BBB is absent or dysfunctionalabsent or dysfunctional

IV Contrast in NeuroimagingIV Contrast in Neuroimaging

1.1. VesselsVessels

2.2. MeningesMeninges

pachy = durapachy = dura

lepto = pia-arachnoidlepto = pia-arachnoid

3.3. Circumventricular organsCircumventricular organs (structures outside BBB)(structures outside BBB)

Pineal glandPineal gland

Pituitary glandPituitary gland

Choroid plexusChoroid plexus

1.1. Absent/leaky BBBAbsent/leaky BBB

Some tumorsSome tumors

InflammationInflammation

InfarctionInfarction

IV Contrast in NeuroimagingIV Contrast in Neuroimaging

Enhancement:Enhancement:

EnhancementEnhancementT1T1 T1+CT1+C

Hemorrhagic melanoma metastasisHemorrhagic melanoma metastasis

IV Contrast: Is it IV Contrast: Is it Indicated?Indicated?

TraumaTrauma R/O hemorrhageR/O hemorrhage HydrocephalusHydrocephalus DementiaDementia EpilepsyEpilepsy

NeoplasmNeoplasm Infection Infection Inflammatory diseaseInflammatory disease

Typically notTypically not Typically yesTypically yes

Always best to provide Always best to provide detailed indicationdetailed indication!!

Radiologist will protocol exam accordinglyRadiologist will protocol exam accordingly

MR vs. CTMR vs. CT

Advantages:Advantages:

• Simpler, cheaper, more accessibleSimpler, cheaper, more accessible

• Tolerated by claustrophobicsTolerated by claustrophobics

• No absolute contraindicationsNo absolute contraindications

• Fewer pitfalls in interpretationFewer pitfalls in interpretation

• Better than MR for bone detailBetter than MR for bone detail

Disadvantages:Disadvantages:

• Ionizing radiationIonizing radiation

• IV contrast complicationsIV contrast complications

• Need recons for multi-planarNeed recons for multi-planar

• Limited range of tissue contrastsLimited range of tissue contrasts

CTCT MRMR


• Much broader palette of tissue contrasts (including Much broader palette of tissue contrasts (including functional and molecular) yields greater anatomic detail functional and molecular) yields greater anatomic detail and more comprehensive analysis of pathologyand more comprehensive analysis of pathology

• No ionizing radiationNo ionizing radiation

• Direct multi-planar imagingDirect multi-planar imaging

• IV contrast better tolerated (in most pts.)IV contrast better tolerated (in most pts.)


• Higher cost, limited accessHigher cost, limited access

• Difficult for unstable patientsDifficult for unstable patients

• Several absolute contraindications Several absolute contraindications

•Claustrophobics may need sedationClaustrophobics may need sedation

• Image interpretation more challengingImage interpretation more challenging

• Lacks bone detailLacks bone detail

Fluoroscopy (Real-Time X-Ray)Fluoroscopy (Real-Time X-Ray)

Fluoro-guided procedures:Fluoro-guided procedures:

• AngiographyAngiography

• MyelographyMyelography

Other Studies - AngiogramOther Studies - Angiogram

Some neurologists Some neurologists just want to look at just want to look at blood vessels in the blood vessels in the brainbrain

They can inject a They can inject a contrast agent and contrast agent and then use x-rays to see then use x-rays to see the blood flowing the blood flowing inside the arteryinside the artery


Digital Subtraction AngiographyDigital Subtraction Angiography

Interventional RadiologyInterventional Radiology

Interventional Interventional radiologists use x-radiologists use x-rays and other rays and other imaging tools in the imaging tools in the operating room to operating room to perform minimally perform minimally invasive surgeryinvasive surgery

• Aneurysms, vascular malformations and fistulaeAneurysms, vascular malformations and fistulae• Vessel stenosis, thrombosis, dissection, pseudoaneurysmVessel stenosis, thrombosis, dissection, pseudoaneurysm• Stenting, embolization, thrombolysis (mechanical and pharmacologic) Stenting, embolization, thrombolysis (mechanical and pharmacologic)

• Ability to interveneAbility to intervene• Time-resolved blood flow dynamics (arterial, capillary, venous phases)Time-resolved blood flow dynamics (arterial, capillary, venous phases)• High spatial and temporal resolutionHigh spatial and temporal resolution

• Invasive, risk of vascular injury and strokeInvasive, risk of vascular injury and stroke• Iodinated contrast and ionizing radiationIodinated contrast and ionizing radiation

Indications:Indications:





MyelographyMyelography

Lumbar or cervical punctureLumbar or cervical puncture

Inject contrast intrathecally with Inject contrast intrathecally with fluoroscopic guidancefluoroscopic guidance

Follow-up with post-myelo CT (CT Follow-up with post-myelo CT (CT myelogram)myelogram)

MyelographyMyelography

• Spinal stenosis, nerve root compressionSpinal stenosis, nerve root compression• CSF leakCSF leak• MRI inadequate or contraindicatedMRI inadequate or contraindicated

• Defines extent of subarachnoid space, identifies spinal blockDefines extent of subarachnoid space, identifies spinal block

• Invasive, complications (CSF leak, headache, contrast reaction, etc.)Invasive, complications (CSF leak, headache, contrast reaction, etc.)• Ionizing radiation and iodinated contrastIonizing radiation and iodinated contrast• Limited coverageLimited coverage




UltrasoundUltrasound

carotidcarotid

US transducerUS transducer

UltrasoundUltrasound

• Carotid stenosisCarotid stenosis• Vasospasm - Transcranial Doppler (TCD)Vasospasm - Transcranial Doppler (TCD)• Infant brain imaging (open fontanelle = acoustic window)Infant brain imaging (open fontanelle = acoustic window)

• Noninvasive, well-tolerated, readily available, low costNoninvasive, well-tolerated, readily available, low cost• Quantitates blood velocity Quantitates blood velocity • Reveals morphology (stability) of atheromatous plaquesReveals morphology (stability) of atheromatous plaques

• Severe stenosis may appear occludedSevere stenosis may appear occluded• Limited coverage, difficult through air/boneLimited coverage, difficult through air/bone• Operator dependentOperator dependent




Ultrasound – Gray ScaleUltrasound – Gray Scale

Gray-scale image of carotid arteryGray-scale image of carotid artery

Ultrasound – Gray ScaleUltrasound – Gray Scale

Gray-scale image of carotid arteryGray-scale image of carotid artery

Plaque in ICAPlaque in ICA

Ultrasound - Color DopplerUltrasound - Color Doppler

Peak Systolic Velocity (cm/sec)Peak Systolic Velocity (cm/sec) ICA Stenosis (% diameter)ICA Stenosis (% diameter)

125 – 225125 – 225 50 – 7050 – 70

225 – 350225 – 350 70 – 9070 – 90

>350>350 >90 >90

Neuroradiology is a rapidly Neuroradiology is a rapidly advancing field of medicine…advancing field of medicine… Scientists are creating stronger and stronger Scientists are creating stronger and stronger

magnets to create clearer MR images of the magnets to create clearer MR images of the brain!brain!

Neuroradiology is a rapidly Neuroradiology is a rapidly advancing field of medicine…advancing field of medicine…

You can also use MR to show areas of blood flow You can also use MR to show areas of blood flow in different regions in the brain - this is called in different regions in the brain - this is called functional MRIfunctional MRI

What part of the brain is abnormal in these What part of the brain is abnormal in these images? What does this patient have?images? What does this patient have?

4th ventricle4th ventricle

Pons

Pons

Temporal lobe

Occipitallobe

Temporal lobe Basillar

artery

MiddleCerebellarpeduncle

ANATOMYANATOMY

ANATOMYANATOMY

Supracellarcistern

MiddleCerebralarteryCerebralpeduncleAqueduct

Of Sylvius TemporalHorn lateralventicle

Opticchiasm

PutamenGlobuspallidus

Caudatehead

Thalamus

ALIC

PLICPLIC

ALICMiddleCerebralartery

Corpuscallosum

Externalcapsule

ANATOMY

ANATOMYANATOMY

CorpuscallosumLateralventricleCorona

radiata

AnteriorCerebralartery

MiddleCerebralartery

Occipitallobe

Parietallobe

Frontallobe

ANATOMYANATOMY

CentrumSemiovale

ENHANCED SCANSENHANCED SCANS BLOOD/BRAIN BARRIER DISRUPTIONBLOOD/BRAIN BARRIER DISRUPTION IDENTIFY PATHOLOGYIDENTIFY PATHOLOGY

ARTERIOGRAM EFFECTSARTERIOGRAM EFFECTS

GADOLINEUM IMAGINGGADOLINEUM IMAGINGMR CONTRASTMR CONTRAST

CT WITH CONTRAST ENHANCEMENT

ENHANCING RING LESION

NON ENHANCED

T1- SCAN – WITHOUT GADOLINEUM

T1 – SCAN WITH GADOLINEUM

T2- SCAN

MR

VASCULAR ANATOMYVASCULAR ANATOMY

CCA

ICAECA

CavernousCarotid

CCA

ICA

Vertebralartery

Basilarartery

Middlecerebral

Carotidbulb

Anterior cerebral

ECA

MR ARTERIOGRAM


Cavernouscarotid

MCABA

ACA

Basilarartery

Anteriorcerebral

MCA

Cavernouscarotid

ECA

ICA

Vertebral

TIME OF FLIGHT MRA

TOF-MRA


MCA

ACoA

ACA

ICA PCoA

Basilar Artery

Circle of Willis

PCA

VASCULAR DISTRIBUTIONSVASCULAR DISTRIBUTIONS

MCA

ACA

PCA

MR PERFUSIONMR PERFUSIONGadolineum InjectionGadolineum Injection

CT PERFUSIONCT PERFUSIONIodine InjectionIodine Injection

Neuro-AnatomyNeuro-Anatomy

Skull and Meninges (Dura, Pia)Skull and Meninges (Dura, Pia)Vasculature: Veins and ArteriesVasculature: Veins and ArteriesSurface Anatomy-Lobes, gyri, SulciSurface Anatomy-Lobes, gyri, SulciHistologic-Broadman’sHistologic-Broadman’sFunctional-motor, sensory, speechFunctional-motor, sensory, speechWhite MatterWhite MatterCross sectional imagingCross sectional imaging

Skull and MeningesSkull and Meninges

Intracranial Hemorrhage

http://www.teaching-biomed.man.ac.uk/resources/wwwcal/cranial_nerves/page1.asp

Cranial nervesCranial nerves

Arterial Blood SupplyArterial Blood Supply

Anterior circulation Internal carotid arteriesPosterior circulation Vertebral arteries

Anatomy and Vascular Territories of the 3 Main Cerebral Arteries:

Middle Cerebral Artery

Anterior Cerebral Artery and Posterior Cerebral Artery

Cortical Areas Supplied by the MCA, ACA and PCA

Superficial and Deep Arterial Supply to the Cerebral HemispheresCoronal Plane

Superficial and Deep Arterial Supply to the Cerebral HemisphereAxial Plane

Lenticulostriate Arteries Supply the Basal Ganglia and Internal Capsule

Arterial Supply of the Thalamus and Basal Ganglia

Ischemic: MCA Infarct

Ischemic: Lacunar Infarct

Ischemic: Basilar ThrombosisIschemic: Basilar Thrombosis

Surface Anatomy-LobesSurface Anatomy-Lobes

http://faculty.washington.edu/chudler/lobe.html

Surface Anatomy-Gyri & Surface Anatomy-Gyri & SulciSulci

http://www.univie.ac.at/anatomie2/plastinatedbrain/surfaceanatomy/surface-suplat-text.html

Lateral

http://www.univie.ac.at/anatomie2/plastinatedbrain/surfaceanatomy/surface.html

Medial

Histological Anatomy-Histological Anatomy-Broadman’sBroadman’s

Functional- Motor CortexFunctional- Motor Cortex

Somatic Sensory CortexSomatic Sensory Cortex

Language AreasLanguage Areas

Talaraic AtlasTalaraic Atlas

http://www.neuro.spc.org/talaraic/

White Matter-DTIWhite Matter-DTI

White Matter Fiber TractsWhite Matter Fiber Tracts

Wakana S, Jiang H, Nagae-Poetscher LM, van Zijl PC, Mori S. Fiber tract-based atlas of human white matter anatomy. Radiology. 2004 Jan;230(1):77-87. Epub 2003 Nov 26.

Association Projection Callosum

VentriclesVentricles

http://faculty.washington.edu/chudler/vent.html

Normal CTNormal CT

Normal MRI T1 WeightedNormal MRI T1 Weighted

Normal MRI T2 WeightedNormal MRI T2 Weighted

5D 6Mo 14Mo

AnatomyAnatomy

Radiographic AnatomyRadiographic Anatomy

ML Richardson, Univ. Of Washington


Cervical Spine – AP View


Cervical Spine – Lateral View


Cervical Spine – Oblique View


Cervical Spine – Open-Mouth (Dens) View


Lumbar Spine – AP View


Lumbar Spine – Lateral View

MRI AnatomyMRI Anatomy

Source: CW Kerber and JR Hesselink, Spine Anatomy, UCSD Neuroradiology

Source: CW Kerber and JR Hesselink, Spine Anatomy, UCSD Neuroradiology


At the end of today, you should be able to At the end of today, you should be able to identify the 3 different orientations of the brain as identify the 3 different orientations of the brain as well as a few important structures in the brainwell as a few important structures in the brain

You should also attempt to distinguish CT, T1-You should also attempt to distinguish CT, T1-weighted MR and T2-weighted MR imagesweighted MR and T2-weighted MR imagesConsider a career in neuroradiology! It’s a very Consider a career in neuroradiology! It’s a very rewarding, high-tech specialty with a lot of fun rewarding, high-tech specialty with a lot of fun problem-solving. Neuroradiologists also play an problem-solving. Neuroradiologists also play an important role in diagnosing diseases and important role in diagnosing diseases and helping patients get the most appropriate helping patients get the most appropriate medical care.medical care.

Radiation SafetyRadiation Safety

Diagnostic CT Scans: Assessment of Diagnostic CT Scans: Assessment of Patient, Physician, and Radiologist Patient, Physician, and Radiologist Awareness of Radiation Dose and Awareness of Radiation Dose and Possible RisksPossible RisksLee, C. et al. RadiologyLee, C. et al. Radiology 2004;231:393 2004;231:393


Deterministic EffectsDeterministic EffectsHave a threshold below which no effect will Have a threshold below which no effect will

be seen.be seen.

Stochastic EffectsStochastic EffectsHave no threshold and the effects are based Have no threshold and the effects are based

on the dose x quality factor.on the dose x quality factor.


TerminologyTerminologyGy = Gray is the absorbed dose (SI unit)Gy = Gray is the absorbed dose (SI unit)

• The equivalent of 1 joule/kg of tissueThe equivalent of 1 joule/kg of tissue• Rad = radiation absorbed doseRad = radiation absorbed dose

Sv = Sievert is the dose equivalent (SI unit)Sv = Sievert is the dose equivalent (SI unit)• Absorbed dose multiplied by a quality factorAbsorbed dose multiplied by a quality factor• Rem = radiation equivalent manRem = radiation equivalent man


Relative values of CT exam exposureRelative values of CT exam exposureBackground radiation is 3 mSv/yearBackground radiation is 3 mSv/year

• Water, food, air, solarWater, food, air, solar• In Denver (altitude 5280 ft.) 10 mSv/yearIn Denver (altitude 5280 ft.) 10 mSv/year

CXR = 0.1 mSvCXR = 0.1 mSvCT head = 2 mSvCT head = 2 mSvCT Chest = 8 mSvCT Chest = 8 mSvCT Abdomen and Pelvis = 20 mSvCT Abdomen and Pelvis = 20 mSv

-The equivalent of 200 CXR


EffectsEffects of X rays. of X rays. Absorption of photons by biological Absorption of photons by biological

material leads to breakage of chemical material leads to breakage of chemical bonds.bonds.

The principal biological effect results The principal biological effect results from damage to DNA caused by either from damage to DNA caused by either the direct or indirect action of radiation.the direct or indirect action of radiation.


Tissue/Organ radiosensitivityTissue/Organ radiosensitivity Fetal cellsFetal cells Lymphoid and hematopoietic tissues; Lymphoid and hematopoietic tissues;

intestinal epitheliumintestinal epithelium Epidermal, esophageal, oropharyngeal Epidermal, esophageal, oropharyngeal

epitheliaepithelia Interstitial connective tissue, fine Interstitial connective tissue, fine

vasculaturevasculature Renal, hepatic, and pancreatic tissueRenal, hepatic, and pancreatic tissue Muscle and neuronal tissueMuscle and neuronal tissue


Estimated Risks of Radiation-Induced Fatal Estimated Risks of Radiation-Induced Fatal Cancer from Pediatric CT Cancer from Pediatric CT David J. BrenneDavid J. Brenner, et al. r, et al. AJRAJR 2001; 176:289-296 2001; 176:289-296

• Additional 170 cancer deaths for each year of head CT in Additional 170 cancer deaths for each year of head CT in the US. the US.

140,000 total cancer deaths, therefore ~ 0.12% increase 140,000 total cancer deaths, therefore ~ 0.12% increase 1 in 1500 will die from radiologically induced cancer1 in 1500 will die from radiologically induced cancer


3094 men received radiation for 3094 men received radiation for hemangiomahemangiomaThose receiving >100 mGyThose receiving >100 mGyDecreased high school attendanceDecreased high school attendanceLower cognitive test scoresLower cognitive test scores

Per Hall, et al. Effect of low doses of ionising radiation in infancy on cognitive function in adulthood: Swedish population based cohort studyBMJ, Jan 2004; 328: 19 - 0.


Hiroshima and NagasakiHiroshima and Nagasaki TThere here has beenhas been no detectable no detectable increase in increase in

genetic defects related to genetic defects related to radiation inradiation in a a large sample (80,000) of survivor offspring, large sample (80,000) of survivor offspring, including:including: congenital abnormalities, congenital abnormalities, mortality (including childhood cancers), mortality (including childhood cancers), chromosome aberrations, or mutations in chromosome aberrations, or mutations in biochemically identifiable genes. biochemically identifiable genes.

William J Schull, Effects of Atomic Radiation: A Half-Century of Studies from Hiroshima and Nagasaki, 1995.


Hiroshima and NagasakiHiroshima and NagasakiHowever, eHowever, exposed individuals who survived xposed individuals who survived

the acute effects were later found to suffer the acute effects were later found to suffer increased incidence of cancer of essentially increased incidence of cancer of essentially all organs.all organs.

William J Schull, Effects of Atomic Radiation: A Half-Century of Studies from Hiroshima and Nagasaki, 1995.

Radiation SafetyRadiation SafetyHiroshima and NagasakiHiroshima and Nagasaki

Most victims with high doses diedMost victims with high doses diedVictims with low doses despite their large Victims with low doses despite their large

numbers are still statistically insignificant.numbers are still statistically insignificant.


Comparison of Image Quality Between Conventional and Low-Dose Nonenhanced Head CT

Mark E. Mullinsa, et al.

AJNR April 2004.

Reduction of mAs from 170 to 90


What does all this mean?What does all this mean?1 CXR approximates the same risk as:1 CXR approximates the same risk as:

• 1 year watching TV (CRT)1 year watching TV (CRT)• 1 coast to coast airplane flight1 coast to coast airplane flight• 3 puffs on a cigarette3 puffs on a cigarette• 2 days living in Denver2 days living in Denver

1 Head CT is approximately 20 CXR1 Head CT is approximately 20 CXR

Health Physics Society on the web--http://hps.org


The pregnant patientThe pregnant patientCan another exam answer the question?Can another exam answer the question?WWhat is the gestational age?hat is the gestational age?Counsel the patientCounsel the patient

• 3% of all deliveries have some type of 3% of all deliveries have some type of spontaneous abnormalityspontaneous abnormality

The motherThe mother’’s health is the primary s health is the primary concern.concern.


"No single diagnostic procedure results in a radiation "No single diagnostic procedure results in a radiation dose that threatens the well-being of the developing dose that threatens the well-being of the developing embryo and fetus."embryo and fetus." -- American College of Radiology -- American College of Radiology

"Women should be counseled that x-ray exposure from a "Women should be counseled that x-ray exposure from a single diagnostic procedure does not result in harmful single diagnostic procedure does not result in harmful fetal effects. Specifically, exposure to less than 5 rad has fetal effects. Specifically, exposure to less than 5 rad has not been associated with an increase in fetal anomalies not been associated with an increase in fetal anomalies or pregnancy loss."or pregnancy loss." -- American College of Obstetricians and -- American College of Obstetricians and GynecologistsGynecologists

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