Ebook Brain Imaging with MRI and CT: Part 1

(BQ) Part 1 book Brain Imaging with MRI and CT presents the following contents: Bilateral predominantly symmetric abnormalities, sellar, perisellar and midline lesions, parenchymal defects or abnormal volume.

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BRAIN IMAGING

An Image Pattern Approach

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BRAIN IMAGING

An Image Pattern Approach

Edited by Zoran Rumboldt

Professor of Radiology, Neuroradiology Section Chief andFellowship Program Director, Department of Radiologyand Radiological Science, Medical University ofSouth Carolina, Charleston, South Carolina, USA

Mauricio Castillo

Professor of Radiology and Section Chief ofNeuroradiology, University of North Carolina School ofMedicine, Chapel Hill, North Carolina, USA

Benjamin Huang

Clinical Assistant Professor of Radiology in theDivision of Neuroradiology, University ofNorth Carolina School of Medicine, Chapel Hill,North Carolina, USA

Andrea Rossi

Head of the Department of Neuroradiology,

G Gaslini Children’s Research Hospital, Genoa, Italy

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Cambridge University Press

The Edinburgh Building, Cambridge CB2 8RU, UK

Published in the United States of America by Cambridge University Press, New York

www.cambridge.org

Information on this title:www.cambridge.org/9780521119443

This publication is in copyright Subject to statutory exception

and to the provisions of relevant collective licensing agreements,

no reproduction of any part may take place without

the written permission of Cambridge University Press

First published 2012

Printed and bound in Great Britain by the MPG Books Group

A catalogue record for this publication is available from the British Library

Library of Congress Cataloging-in-Publication Data

Brain imaging with MRI and CT : an image pattern approach / edited by Zoran Rumboldt [et al.]

p cm

Includes bibliographical references and index

ISBN 978-0-521-11944-3 (Hardback)

I Rumboldt, Zoran

[DNLM: 1 Neuroimaging–methods 2 Diagnosis, Differential 3 Magnetic Resonance Imaging–methods

4 Tomography, X-Ray Computed–methods WL 141]

616.80047548–dc23 2012000482

ISBN 978-0-521-11944-3 Hardback

Cambridge University Press has no responsibility for the persistence or

accuracy of URLs for external or third-party internet websites referred to

in this publication, and does not guarantee that any content on such

websites is, or will remain, accurate or appropriate

Every effort has been made in preparing this book to provide accurate and up-to-date information

which is in accord with accepted standards and practice at the time of publication Although case

histories are drawn from actual cases, every effort has been made to disguise the identities of the individualsinvolved Nevertheless, the authors, editors and publishers can make no warranties that the information containedherein is totally free from error, not least because clinical standards are constantly changing through research andregulation The authors, editors and publishers therefore disclaim all liability for direct or consequential damagesresulting from the use of material contained in this book Readers are strongly advised to pay careful attention toinformation provided by the manufacturer of any drugs or equipment that they plan to use

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Maria Vittoria Spampinato

2 Neurofibromatosis Type 1 – UBOs 4

13 Global Cerebral Anoxia in Mature Brain 26

Maria Vittoria Spampinato and Zoran Rumboldt

22 CADASIL (Cerebral Autosomal DominantArteriopathy with Subcortical Infarcts andLeukoencephalopathy) 44

25 HIV Encephalopathy 50Zoran Rumboldt and Mauricio Castillo

26 Radiation- and Chemotherapy-InducedLeukoencephalopathy 52

27 Leukoaraiosis (Microangiopathy) 54Alessandro Cianfoni

28 Periventricular Edema in AcuteHydrocephalus 56

Alessandro Cianfoni

29 Hypoglycemia 58Benjamin Huang

30 X-Linked Adrenoleukodystrophy (X-ALD) 60Mariasavina Severino

31 Periventricular Leukomalacia (PVL) 62Alessandro Cianfoni

32 Posterior Reversible EncephalopathySyndrome (PRES, HypertensiveEncephalopathy) 64

33 Alexander Disease 66Mariasavina Severino

34 Metachromatic Leukodystrophy 68Andrea Rossi and Zoran Rumboldt

35 Neurodegenerative Langerhans Cell Histiocytosis(ND-LCH) 70

Zoran Rumboldt and Andrea Rossi

36 Remote Cerebellar Hemorrhage 72Maria Gisele Matheus

37 Spontaneous Intracranial Hypotension 74Maria Vittoria Spampinato

Other Relevant Cases

59 Multiple System Atrophy (MSA) 120Zoran Rumboldt and Mauricio Castillo

60 Maple Syrup Urine Disease (MSUD) 122Andrea Rossi

66 Osmotic Myelinolysis 134

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87 Benign External Hydrocephalus 178

88 Normal Pressure Hydrocephalus 180

Alessandro Cianfoni

89 Alzheimer Disease 182

90 Frontotemporal Lobar Degeneration 184

91 Huntington Disease 186

Zoran Rumboldt and Benjamin Huang

184 Congenital Cytomegalovirus Infection 380

Zoran Rumboldt and Chen Hoffman

Section 2 Sellar, Perisellar and

Matthew Omojola and Zoran Rumboldt

42 Ectopic Posterior Pituitary Lobe 86

Mauricio Castillo

43 Langerhans Cell Histiocytosis 88

56 Progressive Supranuclear Palsy (PSP) 114Alessandro Cianfoni and Zoran Rumboldt

57 Joubert Syndrome 116Maria Vittoria Spampinato

58 Rhombencephalosynapsis 118Chen Hoffman

60 Maple Syrup Urine Disease (MSUD) 122Andrea Rossi

61 Chiari 2 Malformation 124Mauricio Castillo

62 Tectal Glioma 126Maria Gisele Matheus

63 Brainstem Glioma 128Donna Roberts

64 Duret Hemorrhage 130Mauricio Castillo

65 Hypertrophic Olivary Degeneration 132Zoran Rumboldt and Benjamin Huang

66 Osmotic Myelinolysis 134Mauricio Castillo

67 Germinoma 136Mauricio Castillo and Zoran Rumboldt

68 Pineoblastoma 138Mauricio Castillo and Zoran Rumboldt

69 Pineal Cyst 140Mauricio Castillo

70 Vein of Galen Aneurysmal Malformation (VGAM) 142Andrea Rossi

71 Corpus Callosum Dysgenesis 144Maria Gisele Matheus

72 Septo-Optic Dysplasia 146Mariasavina Severino

73 Holoprosencephaly 148Andrea Rossi

74 Atretic Parietal Encephalocele 150Maria Gisele Matheus

75 Dermoid Cyst 152Benjamin Huang

76 Lipoma 154Benjamin Huang

14 Wernicke Encephalopathy 28Giulio Zuccoli

93 Dandy–Walker Malformation 190Andrea Rossi

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Section 3 Parenchymal Defects or

Maria Gisele Matheus

87 Benign External Hydrocephalus 178

88 Normal Pressure Hydrocephalus 180

Alessandro Cianfoni

89 Alzheimer Disease 182

90 Frontotemporal Lobar Degeneration 184

91 Huntington Disease 186

92 Congenital Muscular Dystrophies 188

16 Glutaric Aciduria Type 1 32

Mariasavina Severino

31 Periventricular Leukomalacia (PVL) 62

Alessandro Cianfoni

56 Progressive Supranuclear Palsy (PSP) 114

Alessandro Cianfoni and Zoran Rumboldt

57 Joubert Syndrome 116

61 Chiari 2 Malformation 124Mauricio Castillo

Section 4 Abnormalities Without Signi ﬁcant Mass Effect

100 Laminar Necrosis 206Matthew Omojola

101 Neurocutaneous Melanosis 208Majda Thurnher

102 Superficial Siderosis 210Mauricio Castillo

103 Polymicrogyria 212Maria Vittoria Spampinato

104 Seizure-Related Changes (Peri-Ictal MRIAbnormalities) 214

Mauricio Castillo

105 Embolic Infarcts 216Benjamin Huang

106 Focal Cortical Dysplasia 218Zoran Rumboldt and Maria Gisele Matheus

107 Tuberous Sclerosis Complex 220Maria Gisele Matheus

108 Dysembroplastic Neuroepithelial Tumor(DNT, DNET) 222

Giovanni Morana

109 Nonketotic Hyperglycemia With Hemichorea–

Hemiballismus 224Zoran Rumboldt

110 Hyperdensity Following EndovascularIntervention 226

111 Early (Hyperacute) Infarct 228Benjamin Huang

112 Acute Disseminated Encephalomyelitis (ADEM) 230Benjamin Huang

113 Susac Syndrome 232Mauricio Castillo

114 Diffuse Axonal Injury 234Majda Thurnher

115 Multiple Sclerosis 236Matthew Omojola and Zoran Rumboldt

116 Progressive Multifocal Leukoencephalopathy

CONTENTS

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117 Nodular Heterotopia 240

19 Lissencephaly 38

20 Herpes Simplex Encephalitis 40

Mauricio Castillo and Zoran Rumboldt

123 Central Nervous System Vasculitis 252

Giulio Zuccoli

124 Subacute Infarct 254

Benjamin Huang and Zoran Rumboldt

125 Active Multiple Sclerosis 256

Zoran Rumboldt and Majda Thurnher

30 X-Linked Adrenoleukodystrophy (X-ALD) 60

33 Alexander Disease 66

37 Spontaneous Intracranial Hypotension 74

86 Sturge–Weber Syndrome 176

Section 5 Primarily Extra-Axial Focal

131 Leptomeningeal Cyst 270Benjamin Huang

132 Epidural Hematoma 272Benjamin Huang

133 Subdural Hematoma 274Donna Roberts

134 Empyema 276Mauricio Castillo

135 Secondary (Systemic) Lymphoma 278Zoran Rumboldt

136 Idiopathic Hypertrophic Pachymeningitis 280Zoran Rumboldt

137 Olfactory Neuroblastoma 282Zoran Rumboldt

138 Meningioma 284Alessandro Cianfoni and Zoran Rumboldt

139 Desmoplastic Infantile Ganglioglioma 286Giovanni Morana

140 Hemangiopericytoma 288Zoran Rumboldt

141 Schwannoma 290Giulio Zuccoli

142 Arachnoid Cyst 292Maria Gisele Matheus

143 Epidermoid 294Maria Gisele Matheus

144 Aneurysm 296Zoran Rumboldt

145 Racemose Neurocysticercosis 298Zoran Rumboldt and Mauricio Castillo

146 Ependymal Cyst 300Giovanni Morana

147 Choroid Plexus Cyst 302Benjamin Huang

148 Choroid Plexus Papilloma 304Andrea Rossi

149 Intraventricular Meningioma 306Zoran Rumboldt

150 Central Neurocytoma 308Mauricio Castillo

151 Ventricular Diverticula 310Zoran Rumboldt

54 Colloid Cyst 110Alessandro Cianfoni

67 Germinoma 136Mauricio Castillo and Zoran Rumboldt

68 Pineoblastoma 138Mauricio Castillo and Zoran Rumboldt

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Section 6 Primarily Intra-Axial Masses

Zoran Rumboldt and Majda Thurnher

154 Therapy-Induced Cerebral Necrosis (Radiation

Alessandro Cianfoni and Zoran Rumboldt

159 Tumefactive Demyelinating Lesion 328

Zoran Rumboldt

160 Tuberculoma 330

Mauricio Castillo

161 Oligodendroglioma 332

162 Low-Grade Diffuse Astrocytoma 334

Donna Roberts and Benjamin Huang

163 Gliomatosis Cerebri 336

Mauricio Castillo

164 Mitochondrial Myopathy, Encephalopathy,

Lactic Acidosis, and Stroke-Like Episodes

170 Subependymal Giant Cell Astrocytoma (SEGA) 350

Donna Roberts and Zoran Rumboldt

176 Lhermitte–Duclos (Cowden Syndrome) 362Mauricio Castillo

62 Tectal Glioma 126Maria Gisele Matheus

63 Brainstem Glioma 128Donna Roberts

65 Hypertrophic Olivary Degeneration 132Zoran Rumboldt and Benjamin Huang

B Typically With Blood Products

177 Hypertensive Hematoma 364Zoran Rumboldt

178 Amyloid Hemorrhage – Cerebral AmyloidAngiopathy 366

Zoran Rumboldt

179 Cortical Contusion 368Benjamin Huang

180 Hemorrhagic Neoplasms 370Benjamin Huang

181 Hemorrhagic Venous Thrombosis 372Mauricio Castillo and Benjamin Huang

182 Arteriovenous Malformation 374Zoran Rumboldt

183 Cavernous Angioma (Cavernoma) 376Giulio Zuccoli and Zoran Rumboldt

Section 7 Intracranial Calci ﬁcations Cases

184 Congenital Cytomegalovirus Infection 380Zoran Rumboldt and Chen Hoffman

185 Congenital Toxoplasmosis 382Chen Hoffman

186 Aicardi–Goutie`res Syndrome 384Andrea Rossi

187 Physiologic Basal Ganglia Calcifications 386Benjamin Huang

188 Hyperparathyroidism 388Benjamin Huang

189 Meningioangiomatosis 390Giovanni Morana

190 Vascular Wall Calcification 392Benjamin Huang

191 Dystrophic Calcifications 394Benjamin Huang

192 Calcified Aneurysms 396Zoran Rumboldt

193 Vascular Malformations 396Zoran Rumboldt

194 Cysticercosis 398Matthew Omojola

CONTENTS

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203 Meningioma 406Alessandro Cianfoni

204 Teflon Granuloma 408Zoran Rumboldt

Index 410

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Mauricio Castillo

Professor of Radiology and Section Chief, Neuroradiology,

University of North Carolina School of Medicine,

Chapel Hill, NC, USA

Alessandro Cianfoni

Associate Professor, Neuroradiology, Image Guided Spinal

Procedures, Department of Radiology and Radiological

Science, Charleston, SC, USA, and

Neuroradiology Section Chief

Neurocenter of Southern Switzerland

Lugano, Switzerland

Chen Hoffmann

Sheba Medical Center, Tel Hashomer, Sakler School of

Medicine, Tel Aviv University, Tel Aviv, Israel

Benjamin Huang

Clinical Assistant Professor of Radiology, Division of

Neuroradiology, University of North Carolina School of

Medicine, Chapel Hill, NC, USA

Assistant Professor, Neuroradiology, Department of

Radiology and Radiological Science, Charleston, SC, USA

Giovanni Morana

Department of Pediatric Neuroradiology, G Gaslini

Children’s Research Hospital, Genoa, Italy

Matthew Omojola

Professor, Section of Neuroradiology, Department of Radiology,

University of Nebraska Medical Center, Omaha, NE, USA

Donna RobertsAssistant Professor, Neuroradiology, Department ofRadiology and Radiological Science, Charleston,

SC, USAAndrea RossiHead of the Department of Neuroradiology, G GasliniChildren’s Research Hospital, Genoa, Italy

Zoran RumboldtProfessor of Radiology, Neuroradiology SectionChief and Fellowship Program Director, Department

of Radiology and Radiological Science, MedicalUniversity of South Carolina, Charleston,South Carolina, USA

Mariasavina SeverinoDepartment of Pediatric Neuroradiology, G GasliniChildren’s Research Hospital, Genoa, Italy

Maria Vittoria SpampinatoAssociate Professor, Neuroradiology, Department ofRadiology and Radiological Science, Charleston,

SC, USAMajda ThurnherAssociate Professor of Radiology, Medical University ofVienna, Vienna, Austria

Giulio ZuccoliSection Chief of Neuroradiology, Children’s Hospital ofPittsburgh at the University of Pittsburgh Medical Center,Pittsburgh, PA, USA

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ADC apparent diffusion coefficient

ADEM acute disseminated encephalomyelitis

AESD acute encephalopathy with biphasic seizures and

late reduced diffusion

AGS Aicardi–Goutie`res syndrome

ALS amytrophic lateral sclerosis

APD atypical parkinsonian disorder

APE atretic parietal encephalocele

ATRT atypical teratoid–rhabdoid tumor

AVM arteriovenous malformation

BBB blood–brain barrier

BCAAs branched-chain amino acids

BCKAs branched-chain alpha-keto acids

BEH benign external hydrocephalus

BPP bilateral perisylvian polymicrogyria

CAA cerebral amyloid angiopathy

CADASIL cerebral autosomal dominant arteriopathy with

subcortical infarcts and leukoencephalopathyCAVE cerebro-acro-visceral early lethality

CBD cortico-basal degeneration

CBPS congenital bilateral perisylvian syndrome

CCF carotid-cavernous sinus fistula

CCM cerebral cavernous malformations

CNSV central nervous system vasculitis

CPM central pontine myelinolysis

CPP choroid plexus papilloma

CRP C-reactive protein

CST corticospinal tract

DAI diffuse axonal injury

DAVF dural arteriovenous fistula

DCVT deep cerebral vein thrombosis

DI diabetes insipidus

DIG desmoplastic infantile gangliogliomas

DVST dural venous sinus thrombosis

ECA external carotid arteryEDH epidural (or extradural) hematomaEEG electroencephalography

ENB esthesioneuroblastomaEPPL ectopic posterior pituitary lobeESR erythrocyte sedimentation rate

FA fractional anisotropyFASI focal areas of signal intensityFCD focal cortical dysplasia

FTD frontotemporal dementiaFTLD frontotemporal lobar degenerationGBM glioblastoma multiforme

GCDH glutaryl-CoA dehydrogenaseGCMN giant cutaneous melanocytic neviGFAP glial fibrillary acidic protein

GLHS Go´mez–Lo´pez–Herna´ndez syndromeGOM granular osmiophilic material

HAART highly active antiretroviral therapyHCHB hemichorea–hemiballismus

IAC internal auditory canalICA internal carotid arteryIHP idiopathic hypertrophic pachymeningitisiNPH idiopathic normal pressure hydrocephalusIRIS immune reconstitution inflammatory syndromeJCV John Cunningham polyomavirus

JSRD Joubert syndrome related disorders

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LE limbic encephalitis

LH lymphocytic hypophysitis

LIAS late-onset idiopathic aqueductal stenosis

LINH lymphocytic infundibuloneurohypophysitis

LIPH lymphocytic infundibulopanhypophysitis

MEB muscle–eye–brain disease

MELAS mitochondrial myopathy, encephalopathy, lactic

acidosis, and stroke-like episodes

MIP maximum intensity projection

MLC megalencephalic leukoencephalopathy with

subcortical cysts

MLD metachromatic leukodystrophy

MMSE mini mental status examination

MRA magnetic resonance angiography

MS multiple sclerosis

MSA multiple system atrophy

MSUD maple syrup urine disease

MT magnetization transfer

MTS mesial temporal sclerosis

MVD microvascular decompression

NBIA neurodegeneration with brain iron accumulation

NBO neurofibromatosis bright objects

NMO Neuromyelitis Optica

NPH normal pressure hydrocephalus

ONB olfactory neuroblastoma

OPG optic pathway gliomas

PET positron emission tomography

PKAN pantothenate kinase-associated

neurodegeneration

PLIC posterior limb of the internal capsule

PML progressive multifocal leukoencephalopathy

PNFA progressive nonfluent aphasia

PNH periventricular nodular heterotopia

PNS perineural tumor spreadPRES posterior reversible encephalopathy syndromePSP progressive supranuclear palsy

PSWCs periodic sharp and slow wave complexesPTFE polytetrafluoroethylene

PTPR papillary tumor of the pineal regionPVL periventricular leukomalaciaPVS perivascular spaces

PXA pleomorphic xanthoastrocytomarCBV relative cerebral blood volumeRCC Rathke’s cleft cyst

RCH remote cerebellar hemorrhageRES rhombencephalosynapsis

SBH subcortical band heterotopiaSCC squamous cell carcinoma

SCNSL secondary CNS lymphomaSCP superior cerebellar peduncles

SOV superior ophthalmic vein

SS superficial siderosisSSS superior sagittal sinusSWI susceptibility-weighted images

T2WI T2-weighted imagingTCN therapy-induced (radiation)

cerebral necrosisTDL tumefactive demyelinating lesion

TIA transient ischemic attackTSC tuberous sclerosis complexUBO unidentified bright object

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This book was conceived based on the requests and suggestions

from radiology residents and neuroradiology fellows (especially

once they actually started practicing) and on my own interest in

writing a different kind of book There are already somewhat

similar volumes with a differential diagnosis instead of a textbook

format; however, the pattern approach, by which the entities are

grouped into categories based solely on the imaging findings,

represents a novel concept

The goal of this work is to be useful in real life clinical practice

(as well as the board exams) – it is not intended just for

neuro-radiologists, but probably even more so for practicing general

radiologists, neurologists, neurosurgeons, pediatricians and other

physicians The book starts with the bilateral symmetric and

midline lesion patterns, as these are the easiest ones to miss,

especially by relatively inexperienced readers

The design has been standardized with images on the left-hand

page and the text on the right, and I am personally responsible for

the layouts of well over 1500 pictures Every attempt has been

made to include at least two different patients with each entity,

and there are only a few with a single one, while frequently the

cases comprise images from three or more individuals The text is

concise and broken down into smaller sections, stressing the

distinguishing features, both imaging and clinical, with links to

other similar cases under the differential diagnosis section

The book may be used in different ways: by comparing the

pattern(s) with an actual clinical case; when looking for

charac-teristics of a certain disease process or a normal variant; for

jumping from one case to another through the differential

diagnosis sections; as a test (with the right-hand page covered),and even as a regular book from the beginning to the end

This volume is certainly not aimed at replacing textbooks, butshould rather be viewed as a complementary source It is anattempt at pattern-based approach, not perfect and definitelynot all encompassing There are entities that are not included asseparate cases, such as Krabbe disease, neuromyelitis optica, andlacunar infarcts, to name a few, which were for different reasonsinitially considered They are, however, listed and brieflydescribed under the differential diagnosis sections The objectivewas a book of a reasonable size that would more thoroughly coverthe majority of the common and/or radiologically characteristicentities At some point adding new cases and images, revisingtext, and updating references had to stop

I would like to thank all the contributors, especially myco-editors and friends Mauricio, Ben and Andrea I would alsolike to acknowledge the colleagues from around the world whohave generously provided their excellent cases: Angelika Guten-berg, Chung-Ping Lo, Pranshu Sharma, Se Jeong Jeon, YasuhiroNakata and Zolta´n Patay I would like to thank everybody atCambridge University Press for enabling me to publish the bookwhich I wanted to write for years

Finally, my special thanks go to my parents, Mirjana andZvonko, for their continuous support and promotion of aca-demic activity, and to my wife Tihana and daughters Rita, Fridaand Zora for their patience and understanding

Zoran Rumboldt

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S E C T I O N 1

Bilateral Predominantly Symmetric Abnormalities

Cases

1 Hepatic Encephalopathy

2 Neurofibromatosis Type 1 – UBOs

13 Global Cerebral Anoxia in Mature Brain

20 Herpes Simplex Encephalitis

Mauricio Castillo and Zoran Rumboldt

21 Limbic Encephalitis

Mauricio Castillo

22 CADASIL (Cerebral Autosomal Dominant Arteriopathy with

Subcortical Infarcts and Leukoencephalopathy)

Zoran Rumboldt

24 Canavan Disease

Andrea Rossi and Chen Hoffman

25 HIV Encephalopathy

Zoran Rumboldt and Mauricio Castillo

26 Radiation- and Chemotherapy-Induced Leukoencephalopathy

Andrea Rossi and Zoran Rumboldt

35 Neurodegenerative Langerhans Cell Histiocytosis (ND-LCH)

36 Remote Cerebellar Hemorrhage

37 Spontaneous Intracranial Hypotension

59 Multiple System Atrophy (MSA)

Zoran Rumboldt and Mauricio Castillo

60 Maple Syrup Urine Disease (MSUD)

Andrea Rossi

66 Osmotic Myelinolysis

Mauricio Castillo

87 Benign External Hydrocephalus

88 Normal Pressure Hydrocephalus

Alessandro Cianfoni

89 Alzheimer Disease

90 Frontotemporal Lobar Dementia

91 Huntington Disease

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A B

Figure 1 Sagittal non-contrast T1WI (A) demonstrates hyperintensity of the globus pallidus (arrow) A more medial sagittal T1WI (B) showsincreased signal in the substantia nigra (arrow), dorsal brainstem (white arrowhead), and cerebellum (black arrowhead)

Figure 3 Axial non-contrast T1WI (A) shows

a more subtle globus pallidus hyperintensity(arrows) Sagittal T1WI (B) demonstrates highsignal in the region of the dentate nucleus(arrowheads) in addition to globus pallidus(arrows)

Figure 2 Axial non-contrast T1WI throughthe basal ganglia (A) shows bilateral brightglobus pallidus (arrows) Axial T1WI imagethrough the pons (B) reveals hyperintensityinvolving superior cerebellar peduncles(arrows) and tectum (arrowheads)

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CASE 1 Hepatic Encephalopathy

M A R I A V I T T O R I A S P A M P I N A T O

Specific Imaging Findings

Classic brain MR imaging finding in patients with hepatic

encephalopathy (HE) is bilateral symmetric globus pallidus

hyperintensity on T1-weighted images When more prominent,

high T1 signal is also present in substantia nigra, subthalamic

nucleus, tectum, and cerebellar denatate nucleus, with no

corres-ponding findings on T2-weighted images or on CT Additional

MRI findings include diffuse white matter T2 hyperintensity

involving predominantly the hemispheric corticospinal tract and

focal bright T2 lesions in subcortical hemispheric white matter

MR spectroscopy obtained with short echo time shows depletion

of myo-inositol Myo/Cr ratios are decreased not only in cirrhotic

patients with clinical or subclinical encephalopathy, but also in

individuals without encephalopathy Increased levels of glutamine/

glutamate have also been observed, particularly in severe cases

All these MR imaging findings – bright T1 lesions, white matter

T2 hyperintensity, and MRS abnormalities – tend to improve and

return to normal with restoration of liver function, such as

following a successful liver transplantation Characteristic MRI

appearance of acute hyperammonemic encephalopathy appears

to be bilateral symmetric cortical T2 hyperintensity involving the

insula and cingulate gyrus, best seen on FLAIR and DWI

Pertinent Clinical Information

HE includes a spectrum of neuropsychiatric abnormalities

occur-ring in patients with liver dysfunction Most cases are associated

with cirrhosis and portal hypertension or portal-systemic shunts

It is a reversible metabolic encephalopathy, characterized by

personality changes and shortened attention span, anxiety and

depression, motor incoordination, and flapping tremor of the

hands (asterixis) In severe cases, coma and death may occur

Severe forms of hepatic encephalopathy are usually diagnosed

clinically; however, mild cases are sometimes difficult to identify

even with neuropsychological testing

Differential Diagnosis

Manganese Intoxication

• indistinguishable T1 hyperintensity (same presumed

patho-physiology)

Long-Term Parenteral Nutrition

• indistinguishable T1 hyperintensity (same presumed

patho-physiology)

• abnormalities disappear when manganese is excluded from the

solution

Physiologic Basal Ganglia Calcifications (187)

• typically punctuate to patchy and not diffuse

• calcifications on CT

Neurofibromatosis Type 1 (2)

• typically patchy, not diffuse

Carbon Monoxide Intoxication (3)

• bright T2 signal and reduced diffusion in bilateral globuspallidus

Hypoxic Ischemic Encephalopathy (7)

• bright T1 signal around the posterior limb of the internalcapsule (thalamus, putamen, globus pallidus)

• affects neonatesKernicterus

• increased T1 and T2 signal of the globus pallidus

• affects neonatesBackground

HE (or portal systemic encephalopathy) is caused by inadequatehepatic removal of nitrogenous compounds or other toxinsingested or formed in the gastrointestinal tract Failure of thehepatic detoxification systems results from compromised hepaticfunction as well as extensive shunting of splanchnic blood dir-ectly into the systemic circulation by porto-systemic collateralvessels Factors precipitating hepatic encephalopathy in patientswith chronic hepatocellular disease include dietary protein load,constipation, and gastrointestinal hemorrhage As a result, toxiccompounds, such as ammonia, manganese, and mercaptans gainaccess to the central nervous system These series of events lead tothe development of HE The neurotoxic effects of ammonia aremediated by its effects on several neurotransmitter systems and

on brain energetic metabolism The T1-weighted MRI findingsare considered related to the accumulation of manganese, and itsserum concentration in cirrhotic patients is tripled compared

to normal individuals Manganese accumulation may lead toparkinsonism, especially with substantia nigra involvement.White matter T2 hyperintensity is thought to be caused by mildbrain edema and focal lesions have been linked to spongy degen-eration involving the deep layers of the cerebral cortices and theunderlying U-fibers

3 Miese F, Kircheis G, Wittsack HJ, et al 1H-MR spectroscopy, magnetization transfer, and diffusion-weighted imaging in alcoholic and nonalcoholic patients with cirrhosis with hepatic encephalopathy AJNR 2006; 27:1019–26.

4 Matsusue E, Kinoshita T, Ohama E, Ogawa T Cerebral cortical and white matter lesions in chronic hepatic encephalopathy: MR-pathologic correlations AJNR 2005; 26:347–51.

5 U-King-Im JM, Yu E, Bartlett E, et al Acute hyperammonemic

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Figure 4 Axial FLAIR image at the basal ganglia level

in a 10-year-old patient (A) shows bilateral patchyhyperintense abnormalities primarily involving theglobi pallidi (arrows) FLAIR image acquired 3 years later

at the same level (B) reveals spontaneous regression

of these lesions

Figure 3 Bright foci in medial cerebellum(arrows) are seen on FLAIR (A) and T1WI (B)

Figure 2 T2WI in another patient (A) depicts multiple hyperintense foci (arrows)

predominantly in the thalami without enhancement on post-contrast T1WI (B)

Figure 1 Axial FLAIR image (A) shows bilateral bright signal abnormalities (arrows) in the globi pallidi There is also increased diffusivity

on the ADC map (B) and mild hyperintensity (arrows) on T1WI (C)

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CASE 2 Neuroﬁbromatosis Type 1 – UBOs

A N D R E A R O S S I

Unidentified bright objects (UBOs) are the most common

intra-cranial lesions in patients with neurofibromatosis type 1 (NF1),

occurring in about two-thirds of the patients They typically

appear as hyperintense foci on long repetition time (T2-weighted,

FLAIR, PD) MR images and iso- to mildly hypointense on

T1-weighted images; sometimes they show slight T1 shortening,

which has been related to myelin clumping or microcalcification

Mass effect, vasogenic edema, and contrast enhancement are

characteristically absent These lesions typically appear at around

3 years of age, increase in number and size until 10–12 years, and

then tend to spontaneously decrease in size and number, or even

completely disappear They are typically multiple and most

com-monly involve the white matter and basal ganglia (especially

the globi pallidi), usually in a bilateral asymmetric fashion Other

common locations include the middle cerebellar peduncles,

cere-bellar hemispheres, brainstem, internal capsule, splenium of the

corpus callosum, and hippocampi MRS performed within these

lesions may be normal or show slightly decreased NAA and

increased choline levels

The correlation between the presence and extent of UBOs and the

cognitive deficit or learning disability is still controversial It has

been suggested that the anatomic location of neurofibromatosis

bright objects (NBOs) is more important than their presence or

number It seems that thalamic NBOs are in particular

signifi-cantly associated with neuropsychological impairment A patient

with NF1 may present other CNS lesions (optic pathway tumors

and other brain and/or spine low-grade gliomas), skin lesions

(cafe´-au-lait spotzs, axillary and inguinal freckling and cutaneous

neurofibromas), ocular Lisch nodules and skeletal and skull

manifestations (kyphoscoliosis, overgrowth or undergrowth of

bone, erosive defects due to neurofibromas, pseudoarthrosis of

the tibia and dysplasia of the greater sphenoidal wing)

Low-Grade Gliomas in NF1

• markedly hypointense on T1-weighted images

• mass effect and possible contrast enhancement

• may also spontaneously regress

• symmetric eye-of-the-tiger sign (central hypointensity within

hyperintense globi pallidi)

r e f e r e n c e s

1 Lopes Ferraz Filho JR, Munis MP, Soares Souza A, et al.

Unidentified bright objects on brain MRI in children as a diagnostic criterion for neurofibromatosis type 1 Pediatr Radiol 2008;

38:305–10.

2 DiPaolo DP, Zimmerman RA, Rorke LB, et al Neurofibromatosis type 1: pathologic substrate of high-signal-intensity foci in the brain Radiology 1995; 195:721–4.

3 DeBella K, Poskitt K, Szudek J, Friedman JM Use of “unidentified bright objects” on MRI for diagnosis of neurofibromatosis 1 in children Neurology 2000;54:1646–51.

4 Wilkinson ID, Griffiths PD, Wales JK Proton magnetic resonance spectroscopy of brain lesions in children with neurofibromatosis type 1 Magn Reson Imaging 2001; 19:1081–9.

5 Hyman SL, Gill DS, Shores EA, et al T2 hyperintensities in children with neurofibromatosis type 1 and their relationship to cognitive functioning J Neurol Neurosurg Psychiatry 2007; 78:

1088–91.

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in the globi pallidi, typical for the acutephase of the abnormality Courtesy ofChung-Ping Lo.

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CASE 3 Carbon Monoxide Intoxication

B E N J A M I N H U A N G

The globus pallidus is the most common and characteristic site

of brain involvement in acute carbon monoxide (CO) poisoning

and CT usually shows symmetric hypodensity On MRI, the

pallidi demonstrate low T1 and high T2 signal with reduced

diffusion T1 hyperintensity and a rim of low T2 signal are

sometimes seen, reflecting hemorrhagic necrosis Patchy or

per-ipheral contrast enhancement may occur in the acute phase

Similar MRI findings are occasionally seen in the substantia

nigra, hippocampus and cerebral cortex In patients who develop

a delayed leukoencephalopathy, bilateral symmetric confluent

areas of high T2 signal are found in the periventricular white

matter and centrum semiovale, along with mildly reduced

diffu-sion Diffuse white matter involvement may also be present

Symptoms of mild CO poisoning can include headache, nausea,

vomiting, myalgia, dizziness, or neuropsychological impairment

Severe exposures result in confusion, ataxia, seizures, loss of

consciousness, or death Long-term low-level CO poisoning

may cause chronic fatigue, affective conditions, memory deficits,

sleep disturbances, vertigo, neuropathy, paresthesias, abdominal

pain, and diarrhea On physical examination, patients may

dem-onstrate cherry red lips and mucosa, cyanosis, or retinal

hemor-rhages Suspected CO poisoning can be confirmed with blood

carboxyhemoglobin levels Delayed encephalopathy associated

with CO toxicity typically occurs 2–3 weeks after recovery from

the acute stage of poisoning and is characterized by recurrence of

neurologic or psychiatric symptoms Characteristic symptoms

include mental deterioration, urinary incontinence, and gait

dis-turbances The course of the delayed encephalopathy varies

with the severity of intoxication, and symptoms may resolve

completely or progress to coma or death

Cyanide Intoxication

• may be indistinguishable

PKAN (4)

• symmetric eye-of-the-tiger sign (central hypointensity within

hyperintense globi pallidi)

Global Cerebral Anoxia in Mature Brain (13)

• unlikely to preferentially involve globus pallidus

• bilateral deep gray matter and perirolandic cortex involvement

Methanol Intoxication (5)

• characteristic putaminal necrosis

• caudate nucleus may be involved, globus pallidus is typically

CO poisoning is the most frequent cause of accidental poisoning

in the US and Europe Common sources of CO, a by-product

of incomplete combustion of carbon-based fuels, include faultyfurnaces, inadequately ventilated heating sources, and engineexhaust CO binds avidly to iron in the hemoglobin molecule,with the affinity 250 times higher than that of oxygen, and formscarboxyhemoglobin This results in reduction of the oxygen-carrying blood capacity of the subsequent tissue hypoxia Equallyimportant are the direct cellular effects of CO, primarily inhib-ition of mitochondrial electron transport enzymes by attaching

to their heme-containing proteins Selective vulnerability of theglobus pallidus may be related to its high iron content, as carbonmonoxide binds directly to heme iron Decreased cerebral perfu-sion from an associated cardiovascular insult contributes tothe defect in oxygen transport, and the pathological findings ofdemyelination, edema, and hemorrhagic necrosis are similar tothose of other hypoxic–ischemic lesions Delayed white matterinjury may be the result of polymorphonuclear leukocyte acti-vation, which causes brain lipid peroxidation and myelin break-down Low fractional anisotropy (FA) values correlate withdamage to the white matter fibers in the subacute phase after

CO intoxication in patients with persistent or delayed opathy Administration of 100% normobaric or hyperbaricoxygen is the mainstay of treatment for acute CO poisoningand may improve long-term neurologic sequelae

3 Kinoshita T, Sugihara S, Matsusue E, et al Pallidoreticular damage

in acute carbon monoxide poisoning: diffusion-weighted MR imaging findings AJNR 2005; 26:1845–8.

4 Weaver LK Clinical practice Carbon monoxide poisoning N Engl

J Med 2009; 360:1217–25.

5 Beppu T, Nishimoto H, Ishigaki D, et al Assessment of damage to cerebral white matter fiber in the subacute phase after carbon monoxide poisoning using fractional anisotropy in diffusion tensor imaging.

Neuroradiology 2010; 52:735–43.

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Figure 1 Axial (A) and coronal (B) T2WIsshow symmetrically hypointense bilateralglobus pallidus (arrowheads) with ananteromedial hyperintense area (arrows)resulting in the eye-of-the-tiger sign T1WI(C) shows faint hyperintense pallidi(arrowheads)

Figure 2 Coronal T2WI in anotherpatient reveals hypointense bilateral pallidi(arrowheads) with internal hyperintensity(arrows)

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CASE 4 Pantothenate Kinase-Associated

Neurodegeneration (Hallervorden–Spatz Syndrome)

A N D R E A R O S S I

In pantothenate kinase-associated neurodegeneration (PKAN,

for-merly known as Hallervorden–Spatz syndrome), MRI shows

mark-edly hypointense globi pallidi on T2-weighted images, with a small

hyperintense central or anteromedial area This finding has been

labelled the “eye-of-the-tiger” sign and is highly characteristic of

PKAN; it is visible on both axial and coronal images Gradient-echo

T2*-weighted images show more profound hypointensity owing to

paramagnetic effects T1-weighted images may show a

correspond-ing high signal intensity of the pallida There is no contrast

enhancement CT may reveal symmmetrically increased

attenu-ation, primarily in the anteromedial globus pallidus

This rare autosomal recessive disorder is a part of a group of

diseases called “neurodegeneration with brain iron

accumula-tion” (NBIA) which also includes aceruloplasminemia and

neu-roferritinopathy PKAN typically presents in older children or

adolescents with oromandibular dystonia, mental deterioration,

pyramidal signs, and retinal degeneration Most patients die

within 10 years of the clinical onset, although longer survival

into early adulthood is possible

HARP Syndrome (hypopre-b-lipoproteinemia,

acanthocytosis, retinitis pigmentosa, and pallidal

degeneration)

• may be indistinguishable

Other Forms of NBIA

• “eye-of-the-tiger” sign absent

Toxic Encephalopathies (CO poisoning) (3)

• globus pallidus T2 hyperintensity without hypointense portion

Kernicterus

Methylmalonic Acidemia

Normal Iron Deposition

• iron starts accumulating in the pallidi during later childhoodand adolescence and is usually seen on MRI from approxi-mately 25 years of age onwards

BackgroundThe causal gene, PKAN, is located on the short arm of chromo-some 20 and encodes for pantothenate kinase, which regulatesthe synthesis of coenzyme A from pantothenate, thus participat-ing in fatty acid synthesis and energy metabolism Defectivemembrane biosynthesis may result in cysteine increase, which isbelieved to play a role in the accumulation of iron in the basalganglia, in turn generating the typical MRI appearance of PKAN.PANK2 mutation analysis confirms the diagnosis, and may beused for prenatal diagnosis in affected families

Axonal dystrophy with spheroid bodies is found exclusively inthe brain, while skin or conjunctival biopsy is typically negative.Abnormal increase of iron deposits within the globus pallidus,with rusty brown discoloration and neuroaxonal swelling, isfound on histology Iron deposits occur either around vessels or

as free tissue accumulations and may also involve the substantianigra and red nuclei There are associated dystrophic axons andreactive astrocytes in a similar distribution

r e f e r e n c e s

1 Gordon N Pantothenate kinase-associated neurodegeneration (Hallervorden–Spatz syndrome) Eur J Pediatr Neurol 2002; 6:243–7.

2 Angelini L, Nardocci N, Rumi V Hallervorden–Spatz disease:

clinical and MRI study of 11 cases diagnosed in life J Neurol 1992; 239:417–25.

3 Zhou B, Westaway SK, Levinson B, et al A novel pantothenate kinase gene (PANK2) is defective in Hallervorden–Spatz syndrome Nature Genet 2001; 28:345–9.

4 Savoiardo M, Halliday WC, Nardocci N, et al Hallervorden–Spatz disease: MR and pathologic findings AJNR 1993; 14:155–62.

5 Ching KH, Westaway SK, Gitschier J, et al HARP syndrome is allelic with pantothenate kinase-associated neurodegeneration Neurology 2002; 58:1673–4.

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Figure 1 Axial CT image without contrast

demonstrates symmetric basal ganglia swelling

and hypodensity (arrows) Small hyperdense foci

on the right (arrowhead) are consistent with

hemorrhage

Figure 2 Axial T2WI (A) shows symmetric high signal intensity in bilateral putamina(arrows), as well as in subcortical white matter of the left frontal and bilateral occipitallobes (arrowheads) Corresponding T1WI (B) demonstrates predominantly low signalintensity in these regions with a few small foci of higher signal (arrowheads) in theputamina, compatible with small hemorrhages

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CASE 5 Methanol Intoxication

Initial CT and MRI studies in patients following methanol

inges-tion may be normal CT and MRI performed at least 24 h after

ingestion demonstrate characteristic bilateral necrosis of the

putamina, which appear hypodense and edematous on CT and

hyperintense on T2-weighted MR images Hemorrhagic foci can

also be seen within the putaminal lesions and other basal ganglia

may be involved Contrast-enhanced MR images may

demon-strate peripheral enhancement of putaminal and subcortical

lesions in the acute phase of injury Optic nerve MR imaging

reveals nonspecific T2 hyperintensity Other findings seen in

patients who survive for several days are non-enhancing areas

of necrosis within the peripheral white matter, with sparing of the

subcortical white matter U-fibers

Symptoms of methanol intoxication usually begin after a 12- to

24-h latent period following ingestion Patients typically

experi-ence visual disturbances, including decrease in visual acuity,

visual field defects, color blindness, hyperemia of the optic discs,

and peripapillary nerve fiber edema, and neurologic symptoms,

including weakness, headache, and dizziness Gastrointestinal

complaints (pain, nausea, and vomiting) are also common With

larger consumed doses, seizures, stupor, and coma may occur

Laboratory evaluations will reveal a severe metabolic acidosis

Patients who survive methanol poisoning may have permanent

blindness or irreversible neurologic impairments

Global Cerebral Anoxia in Mature Brain (13)

• cortical involvement common

• no optic nerve involvement

Creutzfeldt–Jakob Disease (12)

• presence of cortical lesions

• gradual onset of symptoms

Leigh Disease (10)

• brainstem involvement common

Wilson Disease (6)

• brainstem involvement common, “Panda sign”

Carbon Monoxide Intoxication (3)

• globus pallidus lesions, putamen is sparedBackground

Methanol is a colorless fluid which smells and tastes similar toethanol It is widely used in industry as a denaturant additive toethanol and is also found in a number of commercially availableproducts including antifreeze, paint removers, windshield washerfluid, and various solvents Methanol has also been found inbootlegged alcohol and fraudulently adulterated alcoholic bever-ages Methanol is metabolized in the liver by the enzyme alcoholdehydrogenase into formaldehyde, which is subsequently metab-olized into formic acid, the metabolite which is primarily respon-sible for methanol’s toxicity Metabolism into formaldehyde is arelatively slow process, which accounts for the latent periodobserved between ingestion and onset of symptoms Accumula-tion of formic acid results in a metabolic acidosis early on Tissuehypoxia caused by formate inhibition of oxidative metabolism(through effects on cytochrome c oxidase) may explain its tox-icity to the brain and optic nerves Hemorrhagic putaminalnecrosis is the pathologic finding that is typical of methanolintoxication, and selective vulnerability of the putamina may bedue to their higher oxygen consumption relative to other struc-tures Acute methanol poisoning is treated with hemodialysis aswell as with ethanol or fomepizole, which inhibits metabolism ofmethanol by alcohol dehydrogenase

r e f e r e n c e s

1 Sefidbakht S, Rasekhi AR, Kamali K, et al Methanol poisoning: acute

MR and CT findings in nine patients Neuroradiology 2007; 49:427–35.

2 Sharma P, Eesa M, Scott JN Toxic and acquired metabolic encephalopathies: MRI appearance AJR 2009; 193:879–86.

3 Blanco M, Casado R, Vazquez F, Pumar JM CT and MR imaging findings in methanol intoxication AJNR 2006; 27:452–4.

4 Barceloux DG, Bond GR, Krenzelok EP, et al American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning Clinical Toxicology 2002; 40:415–46.

5 Spampinato MV, Castillo M, Rojas R, et al Magnetic resonance imaging findings in substance abuse Alcohol and alcoholism and syndromes associated with alcohol abuse Top Magn Reson Imaging 2005;16:223–30.

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in the cerebellar white matter.

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CASE 6 Wilson Disease

Symmetric increased T2 signal in the deep gray matter is typical

for Wilson disease (WD), primarily involving the putamen,

followed by thalami (commonly ventrolateral), caudate, and

globus pallidus Hyperintensity may be characteristically

local-ized to the outer rim of the putamen Globi pallidi sometimes

show very low T2 signal In some patients the characteristic

“giant panda” sign is found in the midbrain: hyperintensity

throughout the tegmentum with relative sparing of red nuclei,

lateral pars reticulata of the substantia nigra, and superior

col-liculi Central and dorsal pons may also be affected Dorsal

pontine involvement with sparing of central tegmental tracts

has been described as a second smaller panda face or “panda

cub” – relatively low signal of central tegmental tracts represents

the eyes and aqueduct represents the mouth Less frequently

affected are claustrum and other gray matter structures,

includ-ing cortex, as well as the white matter, primarily superior and

middle cerebellar peduncles The lesions are usually of

inter-mediate to low T1 signal intensity and do not enhance with

contrast With severe liver failure, symmetric T1 hyperintensity

of globi pallidi may be present, similar to other causes of hepatic

dysfunction Generalized cerebral and cerebellar atrophy are

commonly observed with WD T2 hyperintensities frequently

improve with therapy

WD, also known as hepatolenticular degeneration, affects

mul-tiple organ systems and patients can present in strikingly

diverse ways Hepatic dysfunction is the initial manifestation

in 40–50% of patients, while 40–60% present with neurologic

manifestations Neurologic symptoms usually start in the late

teens, but can occur even earlier Tremor is most frequent,

followed by dysarthria, cerebellar dysfunction, dystonia, gait

abnormalities, and autonomic dysfunction Psychiatric illness

is present in up to two-thirds of patients, most commonly

personality changes and depression Kayser–Fleischer rings –

brown or green corneal pigmentation caused by sulfur–copper

deposition – are the classic WD finding, almost invariably

present in individuals with neurologic or psychiatric symptoms

Diagnosis relies on a battery of tests including slit lamp

exam-ination, serum ceruloplasmin, bound and unbound serum

copper, 24-h urinary copper excretion, and neuroimaging Liver

biopsy for determination of copper content is the single most

sensitive and accurate test, usually performed only when

non-invasive exams are inconclusive Patients with WD require

lifelong treatment with chelating agents (D-penicillamine) or

zinc Liver transplantation is performed for fulminant hepatic

failure

Differential Diagnosis Leigh Disease (10)

• T2 hyperintensity may involve subthalamic and cerebellar tate nucleus

den-• elevated lactate in basal ganglia and CSF on MRSCreutzfeldt–Jakob Disease (12)

• lesions are bright on DWI

• prominent cortical involvement

• posteromedial thalamic involvement in variant formHypoxic Ischemic Encephalopathy (7)

• lesions have decreased diffusivity in the acute phase

• cortical involvement frequently present

• T1 hyperintensity around the internal capsule

• lactate on MRSMethanol Intoxication (5)

• putamen primarily affected, frequently with hemorrhage

• possible white matter edemaBackground

WD is a rare autosomal-recessive disorder caused by mutations inthe ATP7B gene located on chromosome 13 ATP7B protein isinvolved in the process of copper transport by mediating theformation of ceruloplasmin and by transporting excess copperacross hepatocyte membranes into the biliary tract A defect inthis protein results in progressive copper accumulation in hepa-tocytes, ultimately leading to hepatic dysfunction Once the liver’scapacity to store copper is exceeded, unbound copper becomesdeposited in other tissues and organs, including the brain It isassumed that cellular damage is due to direct copper toxicity, butrecent evidence suggests that copper elevation induces cell death

by reducing levels of XIAP, a protein that inhibits apoptosis Theneuroimaging findings presumably reflect a combination ofedema, spongy or cystic gray matter degeneration, gliosis, myeli-nolysis, and demyelination

r e f e r e n c e s

1 Kim TJ, Kim IO, Kim WS, et al MR imaging of the brain in Wilson disease of childhood: findings before and after treatment with clinical correlation AJNR 2006; 27:1373–8.

2 Sinha S, Taly AB, Ravishankar S, et al Wilson’s disease: cranial MRI observations and clinical correlation Neuroradiology 2006; 48:613–21.

3 King AD, Walshe JM, Kendall BE, et al Cranial MR imaging in Wilson’s disease AJR 1996; 167:1579–84.

4 van Wassenaer-van Hall HN, van den Heuvel AG, Algra A, et al.

Wilson disease: findings at MR imaging and CT of the brain with clinical correlation Radiology 1996; 198:531–6.

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Figure 1 Axial T1WIs show prominent bilateral hyperintensities within putamina, globi pallidi and lateral thalami (arrowheads) aroundthe posterior limb of the internal capsule (PLIC), with relative caudate head sparing There is also bilateral cortical brightness (arrows) around theprecentral sulcus.

A B Figure 2.nucleus (arrow) and ventrolateral thalamusBilateral bright posterior lentiform

(arrowhead), surrounding relatively dark PLIC

on T1WI (A) Intermediate echo time MRS(B) shows prominent lactate (arrows)

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CASE 7 Hypoxic Ischemic Encephalopathy

in Term Neonates

M A R I A S A V I N A S E V E R I N O

The findings in Hypoxic Ischemic Encephalopathy (HIE) are

variable and depend on brain maturity, severity and duration

of insult, and timing of imaging studies In moderate-to-severe

HIE at term, the central gray matter is the most frequently

affected with lesions in the lentiform nuclei and thalami,

typically adjacent to the posterior limb of the internal capsule

(PLIC) Cortical abnormalities are characteristically found in the

perirolandic area These lesions are T1 hypointense and T2

hyper-intense in the acute phase (first 2 days), becoming T1

hyperin-tense after 3–5 days An early sign is the loss PLIC on

conventional MR sequences The most reliable sign of HIE, which

also remains for a long time, is the reversal of normal PLIC T1

hyperintensity compared to the adjacent lentiform nucleus and

thalamus

In severe and prolonged HIE at term, there is diffuse brain

swelling and edema, usually sparing the basal ganglia, brainstem,

and cerebellum The lesions rapidly evolve by cavitation,

develop-ing into multicystic encephalopathy In mild HIE, typical MRI

features are characterized by parasagittal lesions involving

vascu-lar boundary zones (watershed injury pattern) Diffusion

imaging shows corresponding bright DWI signal and reduced

apparent diffusion coefficient (ADC) values in the first 24 h

These abnormalities peak at 3–5 days and pseudonormalize by

about the end of the first week MR spectroscopy demonstrates

lactate peak in the affected regions A glutamine–glutamate (Glx)

peak may also be elevated

Term neonates with HIE show signs of intrapartum distress,

severe functional depression with low Apgar scores and metabolic

acidosis documented in the cord blood They require

resuscita-tion at birth and have neurological abnormalities in the first 24 h

(apnea, seizures and hypotonia) with electroencephalographic

(EEG) abnormalities Sarnat and Sarnat classification is based

on clinical scoring system for developmental outcome

subdivid-ing the infants with HIE into three groups: normal, mildly

abnor-mal, and definitely abnormal

• absence of thalamic injury

Manganese Intoxication; Hepatic Encephalopathy (1)

• T1 hyperintensity of the globi pallidi without putaminal orthalamic involvement

• T1 hyperintensity may be present in substantia nigra, tectum,cerebellum

signifi-r e f e signifi-r e n c e s

1 Liauw L, van der Grond J, van den Berg-Huysmans AA, et al Is there a way to predict outcome in (near) term neonates with hypoxic-ischemic encephalopathy based on MR imaging? AJNR 2008; 29:1789–94.

2 Huang BY, Castillo M Hypoxic–ischemic brain injury: imaging findings from birth to adulthood Radiographics 2008; 28:417–39.

3 Chao CP, Zaleski CG, Patton AC Neonatal hypoxic–ischemic encephalopathy: multimodality imaging findings Radiographics 2006; 26(Suppl 1):S159–72.

4 Triulzi F, Parazzini C, Righini A Patterns of damage in the mature neonatal brain Pediatr Radiol 2006; 36:608–20.

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Figure 3 Axial FLAIR image at the level of thecentrum semiovale (A) in an immunocompetentpatient demonstrates bilateral increased signalintensity (arrows) within the posterior sulcalsubarachnoid space, suggesting the presence ofproteinaceous material Corresponding

post-contrast T1WI (B) reveals leptomeningealenhancement within these sulci

Figure 2 Axial T2WI (A) and post-contrast T1WI (B) in a different patient show multiple lesions, predominantly located in the basal ganglia,but also scattered throughout the cerebral hemispheres There is marked edema (arrows) associated with the basal ganglia lesions Innumerableenhancing nodules throughout the cerebellar hemispheres are depicted on post-contrast T1WI (C)

Figure 1 Axial non-enhanced CT image (A) in a patient with AIDS shows multifocal bilateral basal ganglia hypodensities (arrowheads).Corresponding T2WI (B) demonstrates multiple hyperintense lesions in the basal ganglia On post-contrast T1WI (C) there is enhancement withinseveral but not all of these lesions – note the non-enhancing lesion in the tail of the left putamen (arrow)

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CASE 8 Cryptococcosis

Manifestations of cryptococcal CNS infection are varied and

include: (1) meningoencephalitis, (2) gelatinous pseudocysts, (3)

parenchymal or intraventricular miliary nodules/cryptococcomas,

or (4) a combination of these findings Imaging studies (especially

CT) may frequently be normal or show just ventriculomegaly,

which is the most common radiologic abnormality

Meningoen-cephalitis appears as cortical and subcortical hyperintensity on

FLAIR images with associated leptomeningeal (often nodular)

enhancement Gelatinous pseudocysts appear as rapidly enlarging,

well-demarcated, cystic lesions in the basal ganglia and deep white

matter of low density on CT, and signal similar to cerebrospinal

fluid (CSF) on T2- and T1-weighted MRI, without contrast

enhancement On FLAIR images, the lesions may be hyperintense

to CSF The finding of multiple cysts/dilated perivascular spaces in

an immunosuppressed patient is highly suspicious for

cryptococ-cal infection Cryptococcomas appear as enhancing nodular

intra-axial lesions (usually in the deep gray matter and cerebellum) or as

intraventricular lesions with enlarged choroid plexus (choroid

plexitis), leading to hydrocephalus They are T2 hyperintense

similar to pseudocysts, range in size from a few millimeters to

several centimeters, and may have surrounding edema

The CNS and the lung are the two primary sites of infection with

Cryptococcus neoformans Patients with CNS cryptococcosis

typic-ally present with nonspecific signs of subacute or chronic

menin-gitis or meningoencephalitis, including headaches, fever, lethargy,

nausea, vomiting, or memory loss over a period of several weeks

The diagnosis is confirmed by encapsulated yeast cells on direct

microscopic examination of the CSF with India ink, positive CSF

cultures for C neoformans, or detection of the cryptococcal

capsu-lar polysaccharide antigen in the CSF Without appropriate

anti-fungal treatment, cryptococcal meningitis is uniformly fatal

Dilated Perivascular Spaces (168)

• absent parenchymal or leptomeningeal enhancement

• no T2 hyperintensity around the fluid-containing spaces

Other Meningoencephalitides

• no perivascular space enlargement

Cerebral Toxoplasmosis (157)

• focal ring enhancing lesions, “eccentric target sign”

• no perivascular space dilatation

Primary CNS Lymphoma (158)

• focal enhancing lesions with low ADC values

• no perivascular space dilatationBackground

Cryptococcus neoformans is a ubiquitous yeast-like fungus found

in soil contaminated by bird excreta It is the most commonfungal CNS pathogen and the third most common cause ofCNS infection overall (behind HIV and Toxoplasma) in AIDSpatients CNS cryptococcosis can also occur in immunocompe-tent individuals The organism spreads to the CNS by hemato-genous dissemination from a pulmonary focus, and reactivation

of a latent infection is also possible The organisms extend fromthe basal cisterns into the brain via the perivascular (Virchow–Robin) spaces, resulting in pseudocysts filled with the fungi andtheir gelatinous capsular material Cryptococcomas are histolo-gically chronic granulomatous reactions with relatively feworganisms or lesions containing numerous organisms with onlymild inflammation; the latter form resembles gelatinous pseudo-cysts both radiographically and histologically The degree of con-trast enhancement in cryptococcomas correlates to anindividual’s immune status – in severely immunosuppressedpatients there is less inflammatory change and less enhancement.Immune reconstitution inflammatory syndrome (IRIS) may beassociated with Cryptococcus – symptoms of acute cryptococcalmeningitis typically occur weeks to months after starting a highlyactive antiretroviral therapy (HAART) regimen

r e f e r e n c e s

1 Tien RD, Chu PK, Hesselink JR, et al Intracranial cryptococcosis in immunocompromised patients: CT and MR findings in 29 cases AJNR 1991; 12:283–9.

2 Mathews VP, Alo PL, Glass JD, et al AIDS-related CNS cryptococcosis: radiologic–pathologic correlation AJNR 1992; 13:1477–86.

3 Smith AB, Smirniotopoulos JG, Rushing EJ From the archives of the AFIP Central nervous system infections associated with human immunodeficiency virus infection: radiology–pathologic correlation.

Radiographics 2008; 28:2033–58.

4 Haddow LJ, Colebunders R, Meintjes G, et al Cryptococcal immune reconstitution inflammatory syndrome in HIV-1-infected individuals: proposed clinical case definitions Lancet Infect Dis 2010; 10:791–802.

5 Perfect JR, Casadevall A Cryptococcosis Infect Dis Clin N Am 2002; 16:837–74.

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Figure 1 Axial T2WI obtained in amacrocephalic infant with psychomotorretardation and seizures reveals symmetricvery low signal intensity of the ventral thalami(arrowheads) There is associated

hyperintensity (arrows) of the posteriorthalami

Figure 2 Axial T2WI (A) in a 4-year-oldpatient shows swelling and increased signalintensity in the basal ganglia (arrows) Thecerebral hemispheric white matter showsdiffuse abnormal hyperintensity with sparing

of the corpus callosum (arrowheads) AxialT1WI (B) shows hyperintensity of the thalámi(arrows)

Figure 3 Axial T2WI (A) in a 12-year-oldpatient with extrapyramidal symptoms andpsychosis shows hyperintensity of thecerebral white matter There is a mildsymmetric increased signal intensity withswelling of the basal ganglia (arrowheads),while the thalami are hypointense (arrows).T2WI at a higher level (B) better shows notablesparing of the corpus callosum (arrowheads).Courtesy of Zoltán Patay

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CASE 9 Gangliosidosis GM2

Imaging findings in Tay–Sachs (Infantile GM2 Gangliosidosis

Type B) and Sandhoff diseases (Infantile GM2 Gangliosidosis Type

O) are quite similar The lesion pattern in a macrocephalic infant is

highly suggestive and includes symmetrical hyperdensities within

the thalami and/or basal ganglia on brain CT The thalami are

typically hyperintense on T1-weighted images and hypointense on

T2-weighted images In Tay–Sachs disease the posterior part of the

thalami may be T2 hyperintense The putamina, caudate nuclei

and globi pallidi are swollen and hyperintense on T2-weighted

images Widespread white matter changes within the cerebral

hemispheres are also noted with sparing of corpus callosum,

anterior commissure, and posterior limbs of the internal capsules

Brain atrophy appears in the final stages of the disease Diffusion

imaging is usually unremarkable Brain MRS shows decline in the

NAA, increased choline and progressive elevation of myo-inositol

In juvenile and adult GM2 gangliosidosis, there is cerebral and

cerebellar atrophy, generally in combination with slight white

matter signal changes A decrease in T2 signal intensity of the

thalami is also found in a number of other diseases caused by

genetic mutations and it seems to be a sign of lysosomal disease

Patients with infantile GM2 Gangliosidosis forms are

macroceph-alic and present before 6 months of age with a progressive

neurological disease characterized by psychomotor deterioration,

pyramidal and later extrapyramidal (choreoathetosis) signs,

feed-ing problems, and generalized tonic–clonic seizures In the later

stages of the disease, patients are usually deaf and blind (with a

cherry-red spot in one or both maculae in most cases)

Hepato-splenomegaly may be present in Sandhoff disease Death usually

occurs between 2 and 3 years of age Patients with juvenile (onset

at 2–6 years) and adult (onset at 10–40 years) forms usually

exhibit a slower progression of the disease with dysarthria,

extra-pyramidal dysfunction, dementia, psychosis, and depression

Krabbe Disease

• dentate nuclei usually involved while signal abnormality in the

basal ganglia is lacking

• white matter disease does not spare the corpus callosum

• presence of optic nerve enlargement and cranial nerve/spinal

roots enhancement

Fucosidosis

• additional T2 hypointensity and T1 hyperintensity of the globi

pallidi

Neuronal Ceroid Lipofuscinosis

• severe cerebral and cerebellar atrophy associated with whitematter signal changes

• frequent optic nerve atrophyStatus Marmoratus

• loss of differentiation between the gray and white matter

• T2 hypointensity may also involve basal ganglia

• older patients (teenagers, adults)Background

GM2 gangliosidoses are rare lysosomal storage disorders caused

by autosomal recessive mutations in the genes encodingb-hexosaminidase A and/or B, and GM2 activator glycoprotein.Deficient activity of these enzymes leads to accumulation of GM2gangliosides inside neuronal lysosomes, leading to cell death.There are three major, biochemically distinct types: B, O, and

AB Among the B and O types, infantile, juvenile, and adult formscan be distinguished; the AB variant is known only as an infantileform Tay–Sachs disease (B) is more common in Ashkenazi Jewswhile Sandhoff disease (O) and AB variant have no ethnic predi-lection The treatment is supportive and mainly aimed at seizurecontrol

r e f e r e n c e s

1 Autti T, Joensuu R, Aberg L Decreased T2 signal in the thalami may be a sign of lysosomal storage disease Neuroradiology 2007; 49:571–8.

2 Koelfen W, Freund M, Jaschke W, et al GM-2 gangliosidosis (Sandhoff ’s disease): two year follow-up by MRI Neuroradiology 1994; 36:152–4.

3 Patay Z Metabolic disorders In: Pediatric Neuroradiology Brain Tortori-Donati P, Rossi A, eds Springer, New York,

NY, 2005.

4 Maegawa GH, Stockley T, Tropak M, et al The natural history

of juvenile or subacute GM2 gangliosidosis: 21 new cases and literature review of 134 previously reported Pediatrics 2006; 118:e1550–62.

5 Steenweg ME, Vanderver A, Blaser S, et al Magnetic resonance imaging pattern recognition in hypomyelinating disorders Brain 2010; 133:2971–82.

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Figure 1 Axial T2WI shows symmetric

hyperintensity in caudate (arrowheads) and

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CASE 10 Leigh Disease

MR imaging in Leigh disease (LD) usually reveals bilateral

sym-metrical T2 hyperintense lesions of the deep gray matter and

brainstem Putamen is typically involved, followed by the caudate

nuclei The globi pallidi and thalami area less frequently affected

Brainstem lesions including the subthalamic nuclei, substantia

nigra, red nuclei, colliculi, periaqueductal gray matter, and

medulla oblongata are commonly present Cerebellar dentate

nuclei are also a frequent location of T2 hyperintensity Spinal

cord, hemispheric white matter and cerebral cortex involvement

may occur Acutely affected areas may show reduced diffusivity on

ADC maps MRS usually reveals elevated lactate, most prominent

within the lesions Normal MRS, however, does not exclude LD

Leigh disease is a frequently lethal disorder that usually presents

during infancy, and rarely during childhood and later in life

Developmental delay, seizures, and altered consciousness are the

most common presenting symptoms Generalized weakness,

hypotonia, nystagmus, ataxia, dystonia, lactic acidosis and

respiratory failure with apneas are also frequently present

Vis-ceral manifestations comprise failure to thrive, cardiomyopathy,

liver function impairment and proximal renal tubulopathy

Neonatal Hypoxic Ischemic Encephalopathy (7)

• posterior part of the lentiform nuclei, lateral thalami, dorsal

brainstem, perirolandic cortex

• hyperintensities on T1-weighted images surrounding PLIC

Wilson Disease (6)

• globi pallidi hyperintense on T1-weighted images (with liver

involvement)

Encephalitis

• brainstem is usually spared

• lesions are usually asymmetrical

Juvenile Huntington Disease (91)

• may be indistinguishable in the early phase

• caudate and putaminal atrophy appears laterGlutaric Aciduria Type 1 (16)

• high T2 signal of the basal ganglia may be associated withleukoencephalopathy

• widening of the sylvian fissures is characteristic

Background

LS, also known as subacute necrotizing encephalopathy, is agenetically heterogeneous mitochondrial disorder embracing awide spectrum of defects in enzymes involved in cerebral oxida-tive metabolism It is caused by mitochondrial DNA mutations(maternally inherited) or nuclear DNA mutations Accordingly,inheritance may be X-linked recessive (e.g pyruvate dehydrogen-ase deficiency), autosomal recessive (e.g some respiratory chaincomplex I and COX deficiencies), or maternal (mitochondrialDNA), depending on the underlying mutation Pathologically,the lesions are consistent with demyelination leading to spongi-form necrosis, capillary proliferation, cavitation, and gliosis

in the vulnerable structures, which are highly dependent onenergy consumption Although there is no causal treatment ofCNS manifestations of LS, various symptomatic therapeuticmeasures are available, such as dietary modifications with substi-tution of vitamins, coenzymes and hormones, quinone derivatesand dichloroacetate

4 Valanne L, Ketonen L, Majander A, et al Neuroradiologic findings in children with mitochondrial disorders AJNR 1998; 19:369–77.

5 Friedman SD, Shaw DW, Ishak G The use of neuroimaging in the diagnosis of mitochondrial disease Dev Disabil Res Rev 2010; 16:129–35.

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of ﬂow in the deep venous system.

Figure 2 Axial T1WI (A) and T2WI (B) in adifferent patient demonstrate bilateralthalamic edema (diffusely low T1 and high T2signal) with hemorrhagic areas, seen as foci ofT1 hyperintensity and T2 hypointensity(arrowheads)

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