HYDROCEPHALUS OF THE HYDROCEPHALUS OF THE INFANT (ABOUT 86 INFANT (ABOUT 86

CASES)CASES)K.EL KHOU;R.ANDALOUSSI;L.OUZIDANEK.EL KHOU;R.ANDALOUSSI;L.OUZIDANE

PediatricPediatric radiologyradiology departmentdepartment--CHUCHU Ibn Ibn RochdRochd

CasablancaCasablanca--MorrocoMorroco..

IntroductionIntroduction

HydrocephalusHydrocephalus ofof infant infant isis a progressive a progressive distension distension ofof thethe ventriclesventricles ,,causedcaused by an by an anomalyanomaly ofof production or circulation production or circulation ofof thethecerebrospinalcerebrospinal fluidfluid..

ItIt hashas a a greatgreat impact on impact on thethe neurologicneurologic andandpsychomotorpsychomotor developmentdevelopment..

It benefited a lot from the development of It benefited a lot from the development of the the neuroradiologyneuroradiology and from the surgery.and from the surgery.

Patients Patients andand methodsmethods

ItIt’’s a s a retrospectiveretrospective studystudy ofof 86 cases 86 cases ofofinfant infant hydrocephalushydrocephalus hospitalizedhospitalized in de in de neurosurgeryneurosurgery departmentdepartment ofof thethe Ibn Ibn RochdRochdhospitalhospital ofof Casablanca on a Casablanca on a periodperiod ofof 5 5 yearsyears..

EpidemiologyEpidemiology RESULTSRESULTS

FemaleFemale (52.3%)>male (47.7%).(52.3%)>male (47.7%).Age:0Age:0--24 24 monthsmonths ((mostmost patients are patients are underunder 3 3 monthsmonthsoldold).).MaternalMaternal antecedentsantecedents: :

Infections(14%)Infections(14%)DrugDrug administration(9%).administration(9%).

ConsanguinityConsanguinity (12.8%).(12.8%).PersonalPersonal antecedentsantecedents::

MeningitisMeningitis (20%)(20%)FetalFetal distressdistress (7%).(7%).Infections (6%).Infections (6%).No No antecedentsantecedents (61%).(61%).

ClinicalClinical RESULTSRESULTS

SymptomsSymptoms::IncreasingIncreasing headhead circumferencecircumference (48%).(48%).Spinal Spinal dysraphismdysraphism(38%).(38%).

MyelomeningoceleMyelomeningocele ((EncephaloceleEncephalocele..

IntracranialIntracranial hypertension hypertension andand neurologicalneurological troubles (50%):troubles (50%):PsychomotorPsychomotor retardation (17%).retardation (17%).ParaplegiaParaplegia (6%),(6%),paraparesisparaparesis (13%).(13%).Convulsions (6%).Convulsions (6%).

OpticOptic disordersdisorders::SettingSetting sunsun signsign (32.5%).(32.5%).StrabismStrabism (5%).(5%).PapilledemaPapilledema (5%).(5%).OpticalOptical atrophyatrophy (5%).(5%).

Diagnostic testsDiagnostic tests RESULTSRESULTS

SkullSkull radiographsradiographs::RealisedRealised atat 45 patients 45 patients

Normal (47%).Normal (47%).

IntracranialIntracranial hypertension hypertension signssigns (40%):(40%):IncreasingIncreasing headhead circumferencecircumference..

DisjunctionDisjunction ofof thethe sutures.sutures.

Central Central markingsmarkings..

CalvariaCalvaria thinningthinning..

OsseousOsseous gap gap ofof thethe base base ofof thethe occiput (13%).occiput (13%).

Diagnostic testsDiagnostic tests RESULTSRESULTSSpineSpine radiographradiograph::

RealizedRealized atat 20 patients(23%).20 patients(23%).SpinaSpina bifidabifida::

LumboLumbo--sacralsacral(11%).(11%).LumbarLumbar (7%).(7%).DorsoDorso--lumbarlumbar (2.3%).(2.3%).

CranialCranial sonographysonography::RealizedRealized atat 49 patients (57%).49 patients (57%).ConfirmedConfirmed thethe diagnosisdiagnosis ofof hydrocephalushydrocephalus::

TriventricularTriventricular hydrocephalushydrocephalus (36%)(36%)BiventricularBiventricular hydrocephalushydrocephalus (13%).(13%).TetraventricularTetraventricular hydrocephalushydrocephalus (7%).(7%).

EtiologyEtiology::DeterminedDetermined in 17%.in 17%.ArnoldArnold--chiarichiari deformitydeformity (12%).(12%).MeningoMeningo--encephaloceleencephalocele (3.5%).(3.5%).AqueductAqueduct ofof sylviussylvius stenosisstenosis (1.2%).(1.2%).

Transfontanellar ultrasonography:

Hydrocephalus with signs of ventriculitis.

Diagnostic testsDiagnostic tests RESULTSRESULTS

CTCT--scanscan::PerformedPerformed atat 55 patients(64%)55 patients(64%)IdentifiedIdentified thethe etiologyetiology in 42% in 42% ofof cases:cases:

AqueductAqueduct ofof sylviussylvius stenosisstenosis (12%).(12%).Dandy Dandy walkerwalker syndrome (10%).syndrome (10%).TumorTumor (7%)(7%)ArnoldArnold--chiarichiari deformitydeformity (5%).(5%).EncephaloceleEncephalocele (4%)(4%)UndeterminedUndetermined etiologyetiology (24%).(24%).

MRI:MRI:PerformedPerformed atat 3 patients (3.5%)3 patients (3.5%)ShowedShowed::

CerebellarCerebellar tumortumor (1 case)(1 case)Dandy Dandy walkerwalker syndrome(1 case)syndrome(1 case)MeningoMeningo--encephaloceleencephalocele(1 case)(1 case)

Triventricular hydrocephalus with reduced cerebralmantle on an Arnold Chiari malformation.

Triventricular hydrocephalus on an Arnold Chiari malformation associated to a dysgenesis of corpus callosum

CT-scan: hydrocephalus with septums andsigns of ventriculitis.

Ct-scan: Hydrocephalus on a Dandy-Walkermalformation

CONTRAST –ENHANCEND MRI: Tumor of theposterior fossa with upstream hydrocephalus.

EtiologyEtiology RESULTSRESULTS

Spinal Spinal dysraphismdysraphism (24.4%)(24.4%)Arnold Arnold chiarichiari deformitydeformity (16.3%)(16.3%)MeningitisMeningitis (16.3%)(16.3%)AqueductAqueduct ofof sylviussylvius stenosisstenosis (12.8%).(12.8%).Dandy Dandy walkerwalker malformation (10.5%)malformation (10.5%)TumorsTumors (7%).(7%).ProencephalicProencephalic cavitycavity (2.3%)(2.3%)UnknownUnknown (10.5%)(10.5%)

TreatmentTreatment RESULTSRESULTS

VentriculoperitonealVentriculoperitoneal shunt 94%.shunt 94%.ExternalExternal derivationderivation 1.2%.1.2%.TherapeuticTherapeutic abstention 3.6%.abstention 3.6%.EvolutionEvolution::

complications(22%).complications(22%).Valve Valve disfunctiondisfunction (3.6%).(3.6%).MeningitisMeningitis (14%).(14%).RespiratoryRespiratory infection ,infection ,parietalparietal suppuration.suppuration.DeathDeath (2 cases)(2 cases)

PathophysiologyPathophysiology DDISCUSSIONISCUSSION

HydrocephalusHydrocephalus cancan bebe subdividedsubdivided intointo thethefollowingfollowing 3 3 formsforms::

DisordersDisorders ofof CSF production:CSF production:This This isis thethe rarestrarest formform ofof hydrocephalushydrocephalus. . ChoroidChoroid plexus plexus papillomaspapillomas andand choroidchoroid plexus plexus carcinomascarcinomas cancan secretesecrete CSF CSF in in excessexcess ofof itsits absorption. absorption.

DisordersDisorders ofof CSF circulation: CSF circulation: This This formform ofof hydrocephalushydrocephalus resultsresults fromfrom obstruction obstruction ofof thethepathwayspathways ofof CSF circulation. This CSF circulation. This cancan occuroccur atat thethe ventriclesventriclesor or arachnoidarachnoid villivilli. . TumorsTumors, , hemorrhageshemorrhages, , congenitalcongenitalmalformations (malformations (suchsuch as as aqueductalaqueductal stenosisstenosis), ), andand infections infections cancan cause obstruction cause obstruction atat eithereither point in point in thethe pathwayspathways. .

DisordersDisorders ofof CSF absorption: CSF absorption: Conditions, Conditions, suchsuch as as thethe superiorsuperior venavena cava syndrome cava syndrome andandsinus sinus thrombosisthrombosis, , cancan interfereinterfere withwith CSF absorption. CSF absorption.

EpidemiologyEpidemiology DISCUSSION DISCUSSION

Incidence:Incidence:4 to 10 per 1000 4 to 10 per 1000 birthsbirths in USA.in USA.

SexSex--ratio male/ratio male/femalefemale :1.5:1.5Age Age ofof discoverydiscovery :0:0--6 6 monthsmonths..MaternalMaternal age :age :ThereThere isis a a higherhigher riskrisk ofof congenitalcongenitalmalformations malformations whenwhen thethe maternalmaternal age age isis overover 35 35 yearsyears..MaternalMaternal antecedentsantecedents::

Infections.Infections.DrugDrug administration.administration.MaternalMaternal diabetesdiabetes..

PregnancyPregnancy evolutionevolution::MechanicalMechanical dystociadystocia++.++.

ConsanguinityConsanguinity++.++.

ClinicalClinical DISCUSSIONDISCUSSION

SymptomsSymptoms::IncreasingIncreasing headhead circumferencecircumference..IntracranialIntracranial hypertension hypertension signssigns andand neurologicalneurological disordersdisorders::

headacheheadache, , gaitgait disturbancedisturbance, , vomitingvomiting, , andand visualvisual changes changes PsychomotorPsychomotor retardation .retardation .

OpticOptic disordersdisorders::SettingSetting sunsun signsign+++.+++.StrabismStrabism,nystagmus,,nystagmus,upgazeupgaze palsypalsy..OpticOptic atrophyatrophy,,papilledemapapilledema ((hydrocephalushydrocephalus isis consideredconsidered as as thethe thirdthirdcause cause ofof opticoptic atrophyatrophy ofof childrenchildren afterafter ventricularventricular hemorraegehemorraege andandbrainbrain tumorstumors).).

AssociatedAssociated malformations:malformations:Spinal Spinal dysraphismdysraphism ::

FirstFirst cause cause ofof congenitalcongenital hydrocephalushydrocephalus..myelomeningocelemyelomeningocele.+++.+++

PolymalformativePolymalformative syndrome.syndrome.

Diagnostic tests Diagnostic tests DISCUSSIONDISCUSSION

TheThe introduction introduction ofof modernmodern imagingimagingtechniques, as techniques, as brainbrain CTCT--scanscan,,transfontanellartransfontanellar ultrasonographyultrasonography,MRI ,MRI andand brainbrain doppler, doppler, allowedallowed a a lessless invasive invasive diagnosisdiagnosis in in comparisoncomparison withwithventriculographyventriculography andandpneumoencephalographypneumoencephalography..

SkullSkull radiographsradiographs DISCUSSIONDISCUSSION

IncreasingIncreasing headhead circumferencecircumference..

DisjunctionDisjunction ofof thethe sutures.sutures.

CalvariaCalvaria thinningthinning..

EtiologyEtiology researchresearch :ex calcifications in :ex calcifications in toxoplasmosistoxoplasmosis..

EvaluationEvaluation ofof ventriculoperitonealventriculoperitoneal shunt shunt disconnectiondisconnection or or displacementdisplacement ofof thethe shunt shunt cathetercatheter. .

DISCUSSIONDISCUSSIONTransfontanellarTransfontanellar echographyechography

Original reports Original reports discussdiscuss thethe limitedlimited use use ofof US in US in patients patients withwith hydrocephalushydrocephalus andand congenitalcongenitalcerebralcerebral anomalies, but anomalies, but currentcurrent applications applications greatlygreatly expandexpand thethe rolerole ofof US in US in thethe evaluationevaluationofof thethe developingdeveloping central central nervousnervous systemsystem ..In In newbornsnewborns, 5, 5-- to 7.5to 7.5--MHz MHz transducerstransducers are are usedused, , andand 33-- to 5to 5--MHz MHz transducerstransducers are are usedused in in olderolder infants .infants .US US isis suitedsuited especiallyespecially for for evaluatingevaluating thetheventricularventricular systemsystem andand thethe cerebralcerebral mantlemantle ..

BrainBrain CTCT--scanscan DISCUSSIONDISCUSSION

CT CT scanscan ofof thethe headhead delineatesdelineates thethe degreedegree ofofventriculomegalyventriculomegaly andand, in , in manymany cases, cases, thethe etiologyetiology..WhenWhen performedperformed withwith contrastcontrast, , itit cancan show infection show infection andandtumorstumors thatthat cause obstruction. cause obstruction. ItIt alsoalso helpshelps withwith operativeoperative planning planning andand for for thetheevaluationevaluation ofof suspectedsuspected shunt shunt malfunctionmalfunction. . ItIt cancan show show associatedassociated malformations:malformations:

AqueductAqueduct ofof sylviussylvius stenosisstenosis..ArnoldArnold--chiarichiari malformation,malformation,cysticcystic malformations malformations ofof thethe posteriorposteriorfossafossa..DysgenesisDysgenesis ofof corpus corpus callosumcallosum ..Calcifications.Calcifications.

MRI MRI DISCUSSIONDISCUSSION

Malformations Malformations ofof thethe CNS are CNS are bestbest delineateddelineated usingusingMRI. MRI. MRI MRI usuallyusually isis requiredrequired for for betterbetter anatomicanatomic resolutionresolutionpriorprior to to surgicalsurgical intervention. intervention. NonenhancedNonenhanced routine routine cranialcranial MRI MRI cancan image image thethe alteredalteredanatomyanatomy andand provideprovide excellent images in excellent images in allall projections projections (sagittal, axial, coronal), (sagittal, axial, coronal), ofof whichwhich thethe sagittal sagittal viewview isis oneoneofof thethe mostmost usefuluseful ..This This delineatesdelineates thethe extentextent ofof associatedassociated brainbrain anomalies anomalies suchsuch as corpus as corpus callosumcallosum agenesisagenesis, , ChiariChiari malformations, malformations, disordersdisorders ofof neuronal migration, neuronal migration, andand vascularvascularmalformations. malformations. T2T2--weighted images weighted images cancan show show transependymaltransependymal flowflow ofofcerebrospinalcerebrospinal fluidfluid (CSF). (CSF).

BrainBrain doppler doppler DISCUSSIONDISCUSSION

TranscranialTranscranial doppler doppler helpshelps to to studystudy thetheflowflow in in bigbig vesselsvessels andand thethe brainbrainhemodynamichemodynamic ofof infant infant andand childrenchildren in in physiologicphysiologic andand noninvasivenoninvasive conditions.conditions.ItIt cancan show an show an impairmentimpairment ofof thethe cerebralcerebralbloodblood flowflow relatedrelated to an to an increasingincreasingintracranialintracranial pressure.pressure.ItIt’’s a s a recentrecent methodmethod thatthat’’ss notnot enoughenoughevaluatedevaluated..

AntenatalAntenatal diagnosisdiagnosis DISCUSSIONDISCUSSION

US:US:HelpsHelps for for thethe diagnosisdiagnosis ofof somesome cerebralcerebral malformations malformations suchsuch as: as: anencephaliaanencephalia,,encephaloceleencephalocele,,myelomeningocelemyelomeningocele,,hydrocephalushydrocephalusandand posteriorposterior fossafossa cystcyst..HydrocephalusHydrocephalus cancan bebe diagnoseddiagnosed fromfrom 17 17 weeksweeks ofof gestation.gestation.

FetalFetal brainbrain MRI:MRI:ItIt’’s a simple non invasive s a simple non invasive examinationexamination thatthat isis usedused whenwhen a a malformation malformation isis suspectedsuspected on on thethe antenatalantenatal US.US.

AlphafoetoproteinAlphafoetoprotein dosage :dosage :TheThe concentration concentration ofof thisthis proteinprotein in in thethe amnioticamniotic fluidfluid isis increasedincreasedwhenwhen therethere are anomalies in are anomalies in thethe closureclosure ofof thethe neural tube. neural tube.

AmniocentesisAmniocentesis andand caryotype caryotype studiesstudies::To To searchsearch associatedassociated chromosomicchromosomic anomalies.anomalies.

EtiologyEtiology DISCUSSIONDISCUSSION

CongenitalCongenital hydrocephalushydrocephalus::Spinal Spinal dysraphismdysraphism++:++:

MyelomeningoceleMyelomeningocele++:++:HydrocephalusHydrocephalus isis associatedassociated to to myelomeningocelemyelomeningocele in 65% to 95% in 65% to 95% ofof cases.cases.TheThe lumbarlumbar location location isis thethe mostmost frequentfrequent..IsIs almostalmost alwaysalways associatedassociated to to cerebralcerebral malformations (Arnold malformations (Arnold ChiariChiari deformitydeformity).).MRI++, CT.MRI++, CT.

AqueductalAqueductal stenosisstenosis::Second Second etiologyetiology ofof congenitalcongenital hydrocephalushydrocephalus..Familial occurrence has been Familial occurrence has been oftenoften reportedreported..CT: CT: triventriculartriventricular dilatation dilatation withwith normal normal fourthfourth ventricleventricle..MRI:more MRI:more specificspecific to show to show thethe levellevel ofof obstruction.obstruction.

EtiologyEtiology DISCUSSIONDISCUSSIONDandy Dandy walkerwalker syndrome:syndrome:

This syndrome This syndrome isis characterizedcharacterized by by agenesisagenesis or or hypoplasiahypoplasia ofof thethe cerebellarcerebellarvermis, vermis, cysticcystic dilatation dilatation ofof thethe fourthfourth ventricleventricle, , andand enlargementenlargement ofof thetheposteriorposterior fossafossa. .

ApproximatelyApproximately 7070--90% 90% ofof patients have patients have hydrocephalushydrocephalus, , whichwhich oftenoftendevelopsdevelops postnatallypostnatally. .

US,MRI++.US,MRI++.

ArnoldArnold--chiarichiari syndrome:syndrome:TheThe ChiariChiari II malformation II malformation isis a a complexcomplex congenitalcongenital malformation malformation ofof thethe brainbrain, , nearlynearly alwaysalways associatedassociated withwith myelomeningocelemyelomeningocele. .

This condition This condition includesincludes downwarddownward displacementdisplacement ofof thethe medullamedulla, , fourthfourthventricleventricle, , andand cerebellumcerebellum intointo thethe cervical spinal canal .cervical spinal canal .

MRI++,CT,US.MRI++,CT,US.

GreatGreat cerebralcerebral veinvein aneurysmaneurysm::Rare Rare congenitalcongenital arteriovenousarteriovenous malformation.malformation.

HydrocephalusHydrocephalus isis foundfound in 90% in 90% ofof cases cases associatedassociated to to heartheart failurefailure signssigns. .

CT :CT :pinealpineal massmass thatthat stronglystrongly enhancesenhances afterafter contrastcontrast administration.administration.

AngioAngio--MRIMRI++.++.

EtiologyEtiology DISCUSSIONDISCUSSIONCongenitalCongenital infections:infections:

CytomegalovirusCytomegalovirus,,toxoplasmosistoxoplasmosis..AntenatalAntenatal diagnosisdiagnosis++:US or MRI.++:US or MRI.

DysgenesisDysgenesis ofof corpus corpus callosumcallosum ..ArachnoidArachnoid cystscysts ofof thethe midlinemidline..

AcquiredAcquired hydrocephalushydrocephalus::Infection:Infection:

SecondarySecondary hydrocephalushydrocephalus by obstruction by obstruction ofof thethe pathwayspathways ofof CSF CSF circulation:circulation:aqueductaqueduct ,,fourthfourth ventricleventricle issues,issues,peripheralperipheral resorptionresorption..MeningitisMeningitis::staphylococcusstaphylococcus pneumoniaepneumoniae ,,tuberculosistuberculosis ++++

TumorsTumors::MRI++.MRI++.

IntraventricularIntraventricular haemorhagehaemorhage::PrematurePremature newbornnewborn++.++.

TreatmentTreatment DISCUSSIONDISCUSSION

MedicalMedical therapytherapyMedicalMedical therapytherapy isis usuallyusually a a temporizingtemporizing measuremeasure. In . In transienttransientconditions, conditions, suchsuch as sinus occlusion, as sinus occlusion, meningitismeningitis, or , or neonatalneonatalintraventricularintraventricular hemorrhagehemorrhage, , medicalmedical therapytherapy cancan bebe effective.effective.

SurgicalSurgical therapytherapyVentriculoperitonealVentriculoperitoneal shuntingshunting :This :This procedureprocedure isis by far by far thethe mostmostcommoncommon procedureprocedure for CSF diversion .for CSF diversion .VentriculoatrialVentriculoatrial shuntingshunting: This : This procedureprocedure isis usuallyusually thethe firstfirstchoicechoice for patients for patients whowho are are unableunable to have distal abdominal to have distal abdominal catheterscathetersLumboperitonealLumboperitoneal shunts are shunts are usedused in in communicatingcommunicatinghydrocephalushydrocephalus ..ExternalExternal shunt.shunt.VentriculostomyVentriculostomy..

EvolutionEvolution DISCUSSIONDISCUSSION

Complications:Complications:TheThe mostmost commoncommon complications complications differdiffer dependingdepending on on thethe type type ofof shunt shunt andand thethe underlyingunderlying pathophysiologypathophysiology

InfectionInfectionSubduralSubdural hematomashematomas occuroccur almostalmost exclusivelyexclusively in in childrenchildrenwithwith completedcompleted headhead growthgrowth ..Shunt Shunt failurefailure ..OverdrainageOverdrainage ..

OutcomeOutcome andand prognosisprognosis::In In generalgeneral, , outcomeoutcome isis goodgood , , TheThe neurologicneurologic functionfunctionofof childrenchildren isis optimizedoptimized withwith shuntingshunting. Infection, . Infection, especiallyespecially if if repeatedrepeated, , maymay affect cognitive affect cognitive statusstatus. .

ConclusionConclusion

HydrocephalusofHydrocephalusof thethe infant infant isis a a frequentfrequentpathologypathology in in ourour contextcontext..DevelopmentDevelopment ofof antenatalantenatal diagnosisdiagnosis ,,ofof modernmodernimagingimaging techniques, techniques, specificallyspecifically, MRI, , MRI, hashasradicallyradically changedchanged thethe prognosisprognosis ofof thisthispathologypathology..TheThe treatmenttreatment isis essentiallyessentially symptomaticsymptomatic by by ventriculoperitonealventriculoperitoneal shuntingshunting. . ShuntedShunted hydrocephalushydrocephalus shouldshould bebe carefullycarefullyfollowedfollowed––upup by by clinicalclinical andand radiologicradiologicsurveillance.surveillance.

BibliographyBibliographyAliouiAlioui S.S. LL’’hydrochydrocééphalie du nourrisson (phalie du nourrisson (àà propos de 86 cas et revue de la propos de 86 cas et revue de la littlittéérature).Facultrature).Facultéé de mde méédecine de decine de Casablanca.ThCasablanca.Thèèsese nn°°94.2003.94.2003.McLoneMcLone DG.DG. Images in Images in PediatricPediatric NeurosurgeryNeurosurgery. . ChiariChiarimalformations.malformations. PediatrPediatr NeurosurgNeurosurg.. MarMar 2000;32(3):164. 2000;32(3):164. RathRath GP, GP, BithalBithal PK, PK, ChaturvediChaturvedi A.A. AtypicalAtypical presentationspresentations in in ChiariChiari II II malformation.malformation. PediatrPediatr NeurosurgNeurosurg.. 2006;42(6):3792006;42(6):379--82. 82. SainteSainte--Rose C.Rose C. HydrocephalusHydrocephalus in in childhood.Inchildhood.In: : YoumansYoumans JR, JR, eded. . NeurologicalNeurological SurgerySurgery.. Philadelphia, Philadelphia, PaPa::.. WB WB SaundersSaunders CoCo;1996:890;1996:890--926.926.SattarSattar TS, TS, BannisterBannister CM, CM, RussellRussell SA, SA, RimmerRimmer S.S. PrePre--natalnatal diagnosisdiagnosis ofofoccultoccult spinal spinal dysraphismdysraphism by by ultrasonographyultrasonography andand postpost--natal natal evaluationevaluation by by MR scanning.MR scanning. EurEur J J PediatrPediatr SurgSurg.. DecDec 1998;8 1998;8 SupplSuppl 1:311:31--3.3. [[MedlineMedline]]. . TruivitTruivit CL, CL, BackovichBackovich A.A. DisordersDisorders ofof brainbrain developmentdevelopment. In: Atlas SW, . In: Atlas SW, eded. . MagneticMagnetic ResonanceResonance ImagingImaging ofof thethe BrainBrain andand SpineSpine. 2nd . 2nd eded.. Philadelphia: Philadelphia: LippincottLippincott--RavenRaven;1996. ;1996. Ulm B, Ulm B, UlmUlm MR, MR, DeutingerDeutinger J, J, BernaschekBernaschek G.G. IsolatedIsolated DandyDandy--WalkerWalkermalformation: malformation: prenatalprenatal diagnosisdiagnosis in in twotwo consecutiveconsecutive pregnanciespregnancies.. AmAm J J PerinatolPerinatol.. 1999;16(2):611999;16(2):61--3. 3. YildizYildiz H, H, YaziciYazici Z, Z, HakyemezHakyemez B.B. EvaluationEvaluation ofof CSF CSF flowflow patterns patterns ofof posteriorposteriorfossafossa cysticcystic malformations malformations usingusing CSF CSF flowflow MR MR imagingimaging.. NeuroradiologyNeuroradiology.. SepSep 2006;48(9):5952006;48(9):595--605.605.