Dr. Francis Neuffer
Department of
Radiology
USC-SOM

• Review major imaging modalities of neuro imaging.
CT, MR, Ultrasound, Angiography
• Review classic disease states of vascular, traumatic, infectious and neoplastic diseases.

DIGITAL SCOUT FILM SHOWING BEGINNING AND END
OF CT SCAN.
Multiple sectional images are obtained from a preliminary scout image showing the beginning and end of the scan.

iV Contrast enhancement-CT
NON-CONTRAST
STUDY
IV IODINE CONTRAST
STUDY

Supracellar
Cistern
Temporal
Horn lateral ventricle
4 th
Ventricle
Selected images from CT scans posterior fossa level
Basilar
Artery
Pons
Cerebellum

Sylvian fissure
Thalamus
Thalamic level
3 rd ventricle
Atria
Lateral
Ventricle
Falx cerebri

Caudate Nucleus
Internal capsule level
Anterior Horn
Lateral ventricle
Internal capsule
Lentiform nucleus
Occipital
Lobe

Ventricle level
Anterior Horn
Lateral ventricle
Posteror
Horn Lateral ventricle

Body lateral ventricle
Occipital lobe
Lateral ventricle level
Frontal lobe
Parietal lobe
Falx cerebri

Centrum
Semiovale
Supraventricular level
Gyrus
Sulcus
Superior
Sagittal Sinus

• Hydrogen protons align in magnetic field
• Radio frequency(RF) excitation and transmission
• No ionizing radiation

T1 SCAN T2 SCAN
SCANS ARE DESIGNED TO SHOW SPECIFIC TISSUE
AND SPECIFIC PATHOLOGY

T1
The tissue signal varies depending on the type of scan performed.
T2 (CSF/edema)
FLAIR (edema) Diffusion

NORMAL
CEREBRAL ARTERIOGRAM
NORMA L
ULTRASOUND
Flow is seen at the common carotid bifurcation on contrast
X- ray arteriography and B-mode ultrasound.

Color Doppler
The vessel lumen can be imaged with ultrasound and the velocity of the flow can be measured.
A stenotic lesion will show acceleration of flow through the narrowed lumen.

ECA
ACA
MCA
ICA
• CCA common carotid A.
• ICA internal carotid A.
• ECA external carotid A.
• MCA middle cerebral A.
• ACA anterior cerebral A.
CCA

Images of vessels at the Circle of Willis
ACA
MCA

ICA
ACA
Anterior cerebral
Basilar artery
ECA
MCA
ICA
Vertebral artery CCA
Middle cerebral
Carotid bulb
MR Angiogram- venous injection
Images can be obtained at MR by injecting gadolinium and imaging rapidly as the agent circulates through the arterial circuit.

• VASCULAR ISCHEMIA
• TRAUMA
• INFECTIOUS WORKUP
• MALIGNANCY WORKUP

• Ischemia
–
Global
– Focal
Hemorrhage
– Hypertensive hemorrhage
– Amyloid angiopathy
– Hemorrhagic infarction
– Subarachnoid hemorhage

85% ISCHEMIC
15% HEMORRAGHIC
• TREATMENT DIFFERENCE
ANTICOAGULATION FOR ISCHEMIC CVA

NORMAL
STENOSIS

1 DAY POST 2 DAY POST
Note increase in edema

Small vessel = lenticulostriate vessel
MCA proximal branch basal ganglia-thalamic

Anterior Cerebral Artery
Middle Cerebral Artery
Posterior Cerebral Artery
The different vascular distributions of cerebral territories are represented on color coded CT diagrams

Hemorrhage
– Hypertensive hemorrhage
– Amyloid angiopathy
– Hemorrhagic infarction
– Subarachnoid hemorhage

Normal
SUBARACHNOID
HEMORHAGE
Increased density
The supra sellar cistern is white due to the blood mixed with the CSF.

• Blood in the subarachnoid space
– Between the Pia & Arachnoid
– CT – acute blood, increased density
– Rupture of cerebral aneurysm
• “ Worst Headache of Life ”
• Location: basal cisterns, sylvian fissure, cortical sulci.

CAROTID ANEURYSM
Associated with Polycystic Renal disease
And Marfans Syndrome
Aneurysms are often at vascular branch points and show relative deficit of media there which contributes to vessel wall weakness

INTRACEREBRAL HEMORHAGE
HYPERTENSIVE EVENTS
Acute Blood is dense on
Non contrast CT
Pontine Hemorrhage
Thalamic Hemorrhage

CEREBRAL AMYLOID ANGIOPATHY
(CAA)
IS AN IMPORTANT CAUSE OF SPONTANEOUS CORTICAL-
SUBCORTICAL INTRACRANIAL HEMORRHAGE (ICH) IN THE
NORMOTENSIVE ELDERLY.
Chao C P et al. Radiographics 2006;26:1517-1531

Hemorragic infarction —delayed several days
With reperfusion on infarct area there is hemorrhage into infarct zone with local mass effect and midline shift.

• Ischemia
Hemorrhage
– Hypertensive hemorrhage
– Amyloid angiopathy
– Hemorrhagic infarction
– Subarachnoid hemorhage

Comparison of infarct zone and ischemic zone to identify treatment candidates

• Thrombolytic therapy to salvage ischemic brain at the border of the infarct zone (ischemic penumbra).
• Who benefits and how to select?

• Thrombolytic therapy
3-6 hour window
• Risk of hemorrhagic conversion
Typically 3hrs since onset is the limit for initiation of venous thrombolytic therapy. With arterial therapy the window of action can be extended . The risk of bleeding into the infarct zone with reperfusion is a complication that can worsen prognosis.

Rt
Note acute occlusion of Rt. MCA circulation and edema in Rt. hemisphere on CT.
Comparison of the normal Lt. side is shown.
Lt

catheter
Catheter is advanced for thrombolysis of the MCA thrombus with improved perfusion on last injection of contrast.

? Abnormality on CT
Questionable lesion on CT in a Rt. periventricular location.

Compared to CT--MR scans with T1, T2, and diffusion weighted better show the acute evolving ischemic infarction
T1
T2
Diffusion

MR LIMITATIONS
• COMPLEX MR SIGNAL OF HEMORRHAGE
RELATED TO HEMAGLOBIN —Fe EFFECTS
• UNSTABLE PATIENT-PATIENT MOTION
MORE A PROBLEM IN MR (LONGER SCAN TIME)
• CT READILY VISUALIZES BLOOD PRODUCTS
• ACCESS- CT IS AVAILABLE FOR ER PATIENTS

• Ischemia
–
Global
– Focal
Hemorrhage
– Hypertensive hemorrhage
– Amyloid angiopathy
– Hemorrhagic infarction
– Subarachnoid hemorhage

• HEAD TRAUMA

• Venous bleeding from “ bridging veins ” which connect cerebral cortex to Dural sinuses
• Concave inner margin
– Older patient –atrophy enlarged subdural space unstable gait–falls
– Pediatric patient –shaken baby/child abuse small subdural space can lead to herniation

(ACUTE)
Over time the blood breaks down and decreases in density.

Hit head on RT. With superficial scalp hematoma
Subdural hematoma on LT due to tearing of bridging veins with
Deceleration with fall.

FRACTURE
EPIDURAL
HEMATOMA
Cause: laceration of meningeal artery/vein adjacent to inner table.
Lucid interval post trauma –later cns injury due to mass effect
Epidural hematomas are more focal than subdurals since the blood is more confined by the periosteum of the skull.

MIDDLE MENINGEAL ARTERY

SKULL BASE
FRACTURE
Can lead to cerebral spinal fluid leak and risk of meningitis
The purple ecchymosis behind the ear is called Battle sign described as a clinical finding

“ RACCOON EYES ”
Periorbital ecchymosis is another sign of a basal skull fracture. Blood tracks along the periosteum and can collect in soft tissues of the orbital lid.
CSF rhinorhea can occur with fractures extending through cribriform plate

AIR IN FRONTAL SINUS
FRONTAL LOBE CONTUSION
NORMAL CHORIOD PLEXUS
CALCIFICATIONS
TRAUMATIC PNEUMOCEPHALUS
Air extends intracranially from fracture of the skull or through the sinuses.

• Tonsillar - brainstem - cardiopulmonary arrest.
• Falcine - anterior cingulate gyrus –ACA infarct.
• Uncus- temporal lobe-- 3 rd nerve

• CNS INFECTION

• Little role for imaging-can delay treatment
• Lumbar puncture and gram stain
• Meningococcal Bacterial can be fatal
• Headache, Stiff neck, Fever, Photophobia

AND
Spread of sinus infection to the epidural space can occur.

•
•
•
• TOXOPLASMOSIS --ring enhancing lesions
Atrophy -- HIV viral effect
PML -- progressive multifocal leukodystrophy
JC virus reactivated-fatal-rapid

HIV AND TOXOPLASMOSIS ring enhancing lesions on CT noncontrast contrast
Patients with altered immunity are subject to many atypical infections.
Toxoplasmosis is rarely seen in immunocompetent patients.

WHO ARE THE PATIENTS?
• CNS MALIGNANCY
• Metastatic disease- 50/50 -Primary malignancy

• Primary = Metastatic
• Lung, Breast, Renal
• Adult- Supratentorial primary tumors
• Pediatric- Infratentorial primary tumors

The ring enhancing lesion is the site of abnormal blood/brain barrier.
The low density center often is necrotic tissue.
CT WITH CONTRAST

ADULTS
Glioblastoma Multiforme
• Malignant astrocytoma-supratentorial
• Can cross midline -corpus callosum
• Butterfly
Coronal section

Axial section MR with gadolineum contrast

DURAL BASED LESIONS
CAN BE LARGE.
INCREASED DENSITY is due to calcium and not bleeding

• Pediatric- Infratentorial primary tumors

• Pediatric
• Benign
• Cystic with nodule
• Posterior fossa
• Cerebellum

MEDULLOBLASTOMA
• Pediatric-malignant-PNET
• Post fossa -cerebellum
• Spread via CSF

WHO ARE THE PATIENTS?
• VISUAL SYMPTOMS
Bitemporal hemianopsia
• PITUITARY LESIONS-
• impinge on optic chiasm

SKULL
SELLA
MR - BRAIN
NORMAL
PITUITARY

NORMAL
PITUITARY
ADENOMA

• Rathke’s pouch - grow from mouth to between anterior and posterior pituitary
• Bitemporal hemianopsia
• Pediatric patient
• Calcify-Benign

WHO ARE THE PATIENTS?
• HEARING LOSS
• Conduction vs sensory
• Weber and Rinne test

INTERNAL AUDITORY MEATUS LESION
MR SCANS
WITH GADOLINIUM WITHOUT GADOLINIUM
Bilateral lesions associated with Neurofibromatosis 2.

WHO ARE THE PATIENTS?
• CHRONIC NEUROLOGIC SYMPTOMS
• DEMENTIA
• Alzheimers, Multi infarct, Hydrocephalus

NORMAL
ATROPHY
With Alzheimer ’ s disease little is seen on MR and CT except atrophy as a nonspecific finding.

Coronal scans
NORMAL PRESSURE HYDROCEPHALUS
Dllated ventricles
NORMAL NPH

• CSF not absorbed by arachnoid granulations
• Ventricles dilate
• Stretch fibers around ventricles - corona radiata
• Incontinence, Gate disturbance and Dementia
• LP/Shunt improves symptoms

WHO ARE THE PATIENTS?
• CHRONIC NEUROLOGIC SYMPTOMS
• DEMYELINATING DISEASE

ABNORMAL WATER SIGNAL IN THE
CEREBRAL WHITE MATTER
NORMAL
DUE TO DEMYELINAZATION
? MULTIPLE SCLEROSIS
Focal white matter lesions show increased water due to breakdown on myelin at sites of involvement.

• Autoimmune- northern latitudes
• Young adult- female-
• Blurred vision –optic nerve
• Internuclear ophthalmoplegia - CN 3 and 6
• Sensory deficit
• Autonomic dysfunction- bladder/bowel

CT -acute hemorrhage
MR- chronic
Ultrasound- vascular screening
Angiography- intervention