NEURORADIOLOGY พ.อ.หญ ง อนงค ร ตน เกาะสมบ ต กองร งส กรรม โรงพยาบาลพระมงก ฎเกล า

NEURORADIOLOGY พ.อ.หญ ง อนงค ร ตน เกาะสมบ ต กองร งส กรรม โรงพยาบาลพระมงก ฎเกล า

CONTENTS Modality and indication, limitation, contraindication Plain film positioning Normal and abnormal plain film Emergency CT of the brain Clinical application

IMAGING MODALITY Plain film Computer tomography Cerebral angiography Magnetic resonance imaging Ultrasound

PLAIN FILM ศ กษาความผ ดปกต ในการเจร ญของศ รษะและใบหน า ด ความผ ดปกต ของกระด กจากการทาลายเช น infection, metastatic tumor ด fracture หร อ foreign body ใช เป นหล กฐานทาง forensic medicine

Computer tomography Indication Head injury Stroke Increased intracranial pressure - Tumor, hydrocephalus,abscess Pre-op or follow up after surgery

Computer tomography Limitation Bone artifact Isodense lesion Radiation hazard Contrast media risk

Cerebral angiography Indication abnormal vessels(aneurysm,avm) Tumor vascularity, pre-op evaluation Vasculitis Carotid cavernous fistula, pseudoaneurysm

Cerebral angiography Advantage Hemodynamic study, flow and direction Intervention Disadvantage Invasive Contrast media Radiation

Magnetic resonance imaging Indication Tumor Stroke Perfusion study Angiogram : MRA Specific areas: pituitary, IAC, cranial nerves,orbits

Magnetic resonance imaging Advantage High tissue characteristics and resolution Multiplanar imaging No radiation Limitation Long acquisition time Poor bone and calcium details High cost Claustophobia

Magnetic resonance imaging Contraindication Clip aneurysm Pacemaker Ferromagnetic substance Metallic foreign body Long term hazard

Ultrasound Infant brain ผ านทาง fontanelle, anterolateral, posterolateral fontanelle Color doppler US for carotid or vertebral arteries

ORBITOMEATAL LINE The line passes through the outer canthus of the eye and the center of the external auditory meatus. It is used for positioning for radiographic views including Water's view, Perorbital view, Lateral view, and others.

LATERAL VIEW

CALDWELL S VIEW

AP VIEW

TOWNE S VIEW

WATER S VIEW

NORMAL CALDWELL VIEW Inner,outer table Frontal sinus Cribiform plate Ethmoid sinus SOF Petrous apex

NORMAL LATERAL VIEW Coronal,lambdoid,squamosal MMA groove Arachnoid granulation Sphenoid sinus mastoid air cells

NORMAL TOWNE S VIEW Occipital bone Petrous, IAC Lambdoid suture Transverse sinus Foramen magnum Mandibular rami Zygomatic arch

NORMAL WATER S VIEW Maxillary sinus Zygomatic arch Mandible Maxilla Nasal cavity Orbit

CONED SELLA VIEW Anterior clinoid process Posterior clinoid process Sella turcica Dorsum sellae Tuberculum sellae

หล กการแปลผล PLAIN FILM SKULL Size and shape: 1:4-1:1.5 Cranial vault : Thickness, symmetry, sutures,convolutional markings, vascular groove Skull base: Sella turcica Calcification: Facial bones: orbits, PNS, mandible, mastoid, maxilla Soft tissue

Types of fractures Linear fracture Diastatic fracture Comminuted fracture Compound fracture Depressed fracture Base of skull fracture: CSF rhinorrhea Fracture via sinus, mastoid: pneumocephalus

PHYSIOLOGIC CALCIFICATION Pineal gland: 2/3 adult,less than 10mm Habenula : anterior to pineal gland, C shape Choroid plexus: Atrial of lateral ventricles Basal ganglia: Bilateral punctate or conglomerate. Idiopathic, Fahr disease, CO or lead poisoning, metabolic PTH, mitochondrial disease, MELAS Dura: Falx cerebri,tentorial cerebelli,petroclinoid ligament

PATHOLOGIC CALCIFICATION Chronic SDH, old hematoma Parasite Infection: TB, abscess CMV, Toxoplasmosis Vascular: Atherosclerosis,AVM Tumor: Oligodendroglioma, Meningioma, Craniopharyngioma

Increase intracranial pressure Enlarged cranial cavity Convolutional marking Suture separation Erosion of dorsum sellae

Enlarged pituitary fossa Ballooning/ J-shape sella Pituitary gland: adenoma, Rathke cleft cyst Parasellar structure: Meningioma, aneurysm Suprasellar structure: Craniopharyngioma, weakness of diaphragmatic sella, arachnoid cyst

J-Shaped sella

Sclerotic skull lesions Osteoblastic metastasis Paget s disease, osteopetrosis, fibrous dysplasia Fluorosis Chronic anemia: Diploic space,hair on end periosteal reaction Acromegaly: Thick skull, enlarged sinus and mastoid, sellar enlargement

Osteolytic skull lesions Congenital : meningoencephalocele Trauma: leptomeningeal cyst Infection: Osteomyelitis Tumor: epidermoid, Hisiocytosis X, hemangioma Miscelleneous: Paget, FD, hyperpth

BASIC CT BRAIN INTERPRETATION

What is a CAT scan? Cross sectional images are obtained by multiple measurements of the x-rays attenuation from several projections.

SYSTEMATIC APPROACH Symmetry Cross sectional anatomy Window Brain Blood Bone

Arterial Territories Anterior Cerebral Middle Cerebral Posterior Cerebral Basilar Superior Cerebellar Anterior Inferior Cerebellar Posterior Inferior Cerebellar

Supratentorial Territories

From Osborne, A: Neuroradiology

EMERGENCY NEURORADIOLOGY Plain film: Limit evaluation of intracranial pathology CT: Fast, accessible, unstable patient Brain, bone, blood window Limitation: beam hardening artifact at posterior fossa

TRAUMA - Primary effect : Contusion, hemorrhage - Secondary effect : Herniation syndrome, vascular injury and its complication

EXTRAAXIAL HEMORRHAGE Epidural hematoma Subdural hematoma Subarachnoid hemorrhage

EPIDURAL HEMATOMA Bleeding between inner table of skull and outer layer of dura Cause : arterial (90%), venous, other Location : Squamous portion of temporal lobe which contain middle meningeal artery Not cross suture line Biconvex hyperdensity lesion Associated skull fracture common

Epidural Hematoma

SUBDURAL HEMATOMA Acute Subacute Chronic : Uncomplicated, complicated, mixed (acute on top)

SUBDURAL HEMATOMA Bleeding between inner layer of dura and arachnoid Cause : tearing of cortical vein is most common, artery, aneurysm, metastasis, spontaneous, etc Can cross suture line, not cross dural reflection (falx cerebri and tentorial cerebelli)

SUBDURAL HEMATOMA Acute : Crescent shape hyperdensity along hemispheric convexity Subacute : Isodensity lesion to brain parenchyma (density decrease 1.5H.U. per day) Bilateral subacute SDH hematoma: - may be undiagnosed - Sulcal effacement and medially displaced gray-white interface

Subdural hemorrhage

Subacute subdural hemorrhage

SUBDURAL HEMATOMA Chronic : Hypodensity, near CSF density in uncomplicated case Complicated chronic subdural hematoma : Thick membrane, internal septation, loculation from repeated hemorrhage Mixed subdural hematoma : Rebleed into the chronic subdural hematoma, (Acute on top) Hematocrit level

Chronic subdural hemorrhage

Mixed subdural hemorrhgae

SUBARACHNOID HEMORRHAGE Bleeding between arachnoid and pia mater Mild irregular linear hyperdensity in the cistern and sulci Location : Sylvian fissure, cortical sulci, suprasellar cistern, interpeduncular cistern, basal cistern Cause -Traumatic - Non traumatic : aneurysm, AVM

SUBARACHNOID HEMORRHAGE

INTRACEREBRAL HEMORRHAGE Cerebral contusion Intraparenchymal hemorrhage - Traumatic - Non traumatic

CEREBRAL CONTUSION Brain bruise, impacted against bony ridge or falx cerebri Depressed skull fracture Location: temporal lobe, anteroinferior frontal lobe CT: Hypodensity from cerebral edema with petechial hemorrhage

INTRACEREBRAL HEMORRHAGE CAUSE Benign: Hypertension, vascular lesion, trauma, drug, coagulopathy Malignant: Primary or metastatic tumor

INTRACEREBRAL HEMORRHAGE Benign findings: Round to oval shape hyperdensity lesion Swirl sign : inhomogeneous density due to active bleed Malignant findings: Soft tissue density Variable age of blood Vasogenic edema inappropriate to lesion No evolution with time

Hypertensive hemorrhage Cause : Atherosclerosis lentriculostriate artery most affected Ruptured Charcot Bouchard aneurysm Common location Basal ganglia, thalamus, brain stem and cerebellum. Lobar hemorrhage 5% CT findings Homogeneous round to oval shape hyperdensity in typical location. May have intraventricular extension

HERNIATION SYNDROME 1. Subfalcine herniation 2. Transtentorial herniation: ascending, descending 3. Tonsillar herniation 4. Transalar herniation

SUBFALCINE HERNIATION 1.Herniation of affected hemispheric structures across midline under the free margin of falx cerebri 2.Involve corpus callosum, cingulate gyrus, anterior cerebral artery and internal cerebral vein 3.Complication : - Obstructive hydrocephalus - ACA infarction of cingulate gyrus

SUBFALCINE HERNIATION 4.Imaging : - Shift of midline structures - compressed ipsilateral ventricle - obstructive hydrocephalus with dilatation of contralateral ventricle - Hypodensity of cingulate gyrus due to ACA infarction.

TRANSTENTORIAL HERNIATION Descending transtentorial herniation 1. Herniation through tentorial incisura 2. Involve uncus, hippocampus, brain stem, cranial nerve III, PCA 3. Complication - Third nerve compression and palsy - PCA occlusion and infarction - Kernohan notch - Duret hemorrhage

TRANSTENTORIAL HERNIATION Descending transtentorial herniation 4.Imaging : - Medial displacement of uncus of tempotal lobe - Effacement of ipsilateral aspect of suprasellar cistern - Shifting of midbrain against the contralateral tentorial ridge - Hypodensity of contralateral cerebral peduncle from ischemic injury (Kernohan notch). False localizing sign - Duret hemorrhage due to compressed perforator of basilar artery - PCA infarction; Hypodensity of occipital lobe

Ipsilateral suprasellar cistern effacement

TONSILLAR HERNIATION Herniation of cerebellar tonsil via foramen magnum Complication: Obstructive hydrocephalus Imaging : CT : Obliteration of CSF spaces around in cisterna magna MRI Sagittal view: tonsil >5mm below the foramen magnum

Tonsillar herniation

Ascending transtentorial herniation Less common Upward herniation of cerebellar through tentorial incisura Cause : Posterior fossa mass lesion. Complication: Obstructive hydrocephalus Imaging : CT : Obliteration of superior vermian cistern and quadrigeminal plate cistern.

Ascending transtentorial herniation

STROKE - Ischemic stroke - Hemorrhagic stroke

Ischaemic Stroke Thromboembolic most common Hemodynamic Atherosclerotic Dissection Vasospasm Hypotensive /asphyxia (watershed) Migraine Vasculitis Thrombotic: hypercoagulable states

Hemorrhagic Stroke Primary Intracerebral hemorrhage Hypertension Amyloid angiopathy Arteriovenous malformations Neoplasms Trauma Subarachnoid hemorrhage Aneurysm AVM s Trauma

Hyperdense vessel sign & loss of gray/white junction...

Left insular ribbon sign & effacement of sulci

ACA MCA

Left PCA

Watershed (between ACA and MCA)

Hypertensive Hemorrhage Classically involves the deep nucleii

INTRACRANIAL INFECTION Intraaxial: Encephalitis Cerebritis Abscess Extraaxial: Subdural empyema Epidural abscess Meningitis

CEREBRAL INFECTION Encephalitis: generalized and difuse infection of the brain. Often of viral origin (ex.herpes simplex) Cerebritis: localized but poorly demarcated area of parenchymal softening. Abscess: follows cerebritis. Occurs when a central zone of necrosis becomes encapsulated.

MODE OF SPREAD Hematogenous spread Direct extension: ex.sinusitis leading to epidural abscess or subdural empyemas Spread along the nerves (ex.herpes encephalitis along the trigeminal nerve)

SUBDURAL EMPYEMA (C+)

TUBERCULOUS MENINGITIS Basal leptomeningitis (seeding of the subarachnoid space)