18.ThefundamentalsofpediatricradiologyAuthor:vaKis

SemmelweisUniversity1stDepartmentofPediatrics,Budapest

18.1.Differencesbetweenpediatricandadultradiology

Thechildisnotasmalladultitmightseemasaclich,butinfactitisthebasictruth.Childrenandadolescentsufferfromdifferentdiseasesthanadultsandrequiredifferenttherapiesaswellasalteredimagingapproaches.Thestrategiesfordiagnosticimagingaredifferent,althoughthemodalitiesarethesameorsimilartothoseusedinadultradiology.Thesequenceofmodalitychoice,someofthetechnicalparametersandthefollowupprotocolsaredifferentinpediatricradiology.Thenumberonedifferenceisradiationsafety.Childrenareespeciallysensitivetoionizingradiation.Immaturetissuesareextremelysensitivetoradiationandthereisnominimalsafetydosagethatisconsideredabsolutelyharmless.Tissuesingrowthandtheredbonemarrowthattakesupmostofthebonemarrowtissueatthisagegroupareespeciallysensitivetoradiation.Becauseofthesmallerbodysize,thegonadsareclosertotheirradiatedzones.Moreover,becauseofthelongerlifeexpectancyinchildren,thecumulativedoseofnaturalandartificialradiationmeanhigherriskforthedevelopmentofmalignantdiseases.Thebestprotectionistominimizeortocompletelyavoidtheuseofionizingradiationinchildren.This,ononehandmeansstrictcontrolandsupervisionoftheindicationsofXrayandCTexaminations,ontheotherhand,whenpossible,theuseofnonionizingexaminationssuchasultrasoundorMRIarepreferred.TheotherperspectiveofradiationsafetyistodecreasethenumberofXrayexpositionstothebareminimum,meaningthatunnecessaryrepetitions,comparativeormultiangularexaminationsshouldbeavoided.CTexaminationsshouldonlybeperformediftheyareabsolutelynecessaryandifsowiththeuseofspecial,lowdoseprotocols.ThesocalledALARAacronymstandsforAsLowAsReasonablyAchievable,thereforeitmeansthatoneshouldusethelowestdosageofradiationpossible.Thispointofviewcanneverbeneglectedinpediatricradiology.Thischapterismeanttointroducethemostimportantradiologicmodalitiesinchildrenandadolescentcaredifferingfromtheadultradiology,aswellastogiveanoverviewofthemostcommondiseasesinashortandbasicmanner.

18.2.Radiologicdiagnosticsofthechest18.2.1.Thenormalnewbornchest

Normalnewbornlungs:anewbornschestgoesthroughsomefundamentalchangesduringthefirstdaysofextrauterinelife.Theheartisrelativelyrounded,characterizedbythedominanceoftherightside.Thecardiothoracicindextakeninamidinspiratorystateisbetween0.550.62.Expiratorystatecanleadtodiagnosticmistakes.Thymus:isusuallymadeupoftwoasymmetricallobes,situatedintheanteriorsuperiormediastinumandshowsagreatvariabilityofbothsizeandshape.Itdoesnotcauseanycompressionontheneighboringorgans.Onultrasoundexaminationitappearsasahomogenoussolidtissue,relativelymorehypoechoicthanthethyroidgland.Thediaphragmisabitmoreelevatedinmidinspiratorystateitsarchisbetweenthe89thribonthebackandatthe6thribinthefront.Bonythorax:theribsarehorizontalandthesagittalandhorizontaldiametersofthechestareveryclosetoeachother.

1.a.Expiratorystate:thetransparencyofthelungisdiffuselydecreased.

1.b.Inspiratorystate,thelungistransparent,theheartisnormalsized.Ribsrunhorizontallyininfants.

2.Thymushasacontouronbothsides.Healthynewborn.

18.2.2.Afewdiseasesofthenewborns

Wetlung,transitoricustachypnoe.Fetalliquidsinthelungarenotproperlydrainedbythevenousandlymphaticvessels;thenewbornwillshowsignsofdyspneaandtachypnea.OnXray,thechestappearshyperinflated,withdecreasedtransparencyandwitharelativecardiomegaly.Thesesignsusuallydisappearwithin72hours.IRDS(Idiopathicrespiratorydistresssyndrome).Preterminfants,youngerthan34weeks,haveimmaturelungswithsurfactantshortagethatleadstoalveolarinsufficiency.Thebreathingdisorderprogresseswithtimeastachypnea,dyspnea,cyanosisandgruntingoccur.OnXrayimagestherespiratoryvolumewillregressandadiffusereticularnodularpatterncanbeobserved,alsowideairbronchogramswillappearrunningtotheperipheries.Thecontoursoftheheartwillbeblurredorevenacompletelossoftransparencyisvisible(stagesIIV).Surfactantadministeredintimewillresultinimprovedradiologicpicture.Meconiumaspirationsyndrome(MAS).Itisfrequentlythediseaseoftermandposttermnewborns.Thefetusdefecatesmeconiumtotheamnioticfluidthatis

aspiratedatbirth,anditcauseschemicalpneumonitis.Ontheradiographthisisdepictedwithcoarsepatchyandstreakyalveolarshadows.Bronchopulmonarydysplasia(BPD).Itisthepulmonarydamagethatoccursinimmaturenewbornsduetoprolongedperspiration.Itsradiologicpicturedependsonthestageofthedisease,earlysignsofBPDareundistinguishableformIRDS.Inlaterstages,thelungishyperexpandedwithpronouncedcentralreticularpattern.Atelectasisisafrequentcomplicationthatpromotestheappearanceofinfectiousdiseases.

3.Whitelung.IRDS.IV. 4.Asnowstormlikenodularpatchyinfiltrateonbothsidedofthelung.

Meconiumaspiration.

5.Thebasallobesofthelungareinflated,onbothsidesthereisanirregularreticularpattern.BPD.

6.Intestinalshadowsintheleftsideofthechest,themidlineisdislocatedtotheright.Leftsideddiaphragm

hernia.

Congenitaldiaphragmhernias.Itistheresultofabnormaldiaphragmdevelopment.Itsradiologicpictureisinfluencedbyitsseverity,localization,andtimeofduration.Leftsidedherniasaremorefrequent(alsocalledBochdalekhernias).Thenewbornsuffersfromrespiratoryinsufficiency,intestinalanddislocatedheartsoundscanbeheardabovethechest,theabdomeniscollapsed.TherightsideddiaphragmherniaisalsocalledtheherniaofMorgagniandcausesalesssevereclinicalpicture,manytimesdiscoveredaccidentallyontheXray.Onultrasoundthemissingdiaphragmandaherniatedportionoftheliverisseen.

18.2.3.Pneumonia.

Incaseofcharacteristicclinical,auditoryandpercussionexaminationresults(crepitation,bronchialbreathingsounds,dullnessatpercussion)aradiologicexaminationisnotevennecessary.Radiography:forthemajorityofpneumoniasasinglePAchestXrayisenoughforthediagnosis.Theinitialexaminationwithinthefirst24hoursofonsetisgenerallynegative,ifitsclinicallynecessary,controlexamistobeperformed.However,ifthetreatmentforbronchopneumoniaimprovestheclinicalsymptomsXraycanbeneglected.Thefinalconfirmationthattheinfiltratehasbeenresolvedisalwaysdocumentedonaradiograph.Incaseofpleuropneumoniasultrasonographyiscapabletocontrol,toanalyzeandtofollowthecourseofthepleuraleffusion.Therefore,manycontrolXrayexamscanbesubstitutedwithUS.Xrayingeneralisnotappropriatetofullydeterminetheetiologyofpneumonia,butcanbeindicativeinsomecases.StreptococcusBpneumonia:.isanacquiredinfectionafterbirthofmaturenewbornsanditcanmimicIRDS.ThedifferencetoIRDSisthecoarserreticularnodularappearanceaccompaniedbypleuraleffusionatmanytimes.Sometimesscatteredorconfluentperihilarpatterncanberecognized.Staphylococcusaureuspneumonia:isacommonbacterialpneumoniainsmallbabies.ItsclinicalpictureonXrayisaccompaniedbycoarsenodularorconfluentinfiltrations,withfrequentpleuraleffusions.Thepneumonicnodulesconsolidatefastandformpneumatocelesthatcangrowfurtherandpersistforalongertime.Healingusuallylastsformonths.Roundpneumonia:isacharacteristicpediatricdisease.TheroundshapedinfiltrationmimicsatumorontheXrayimage(neuroblastoma,bronchogeniccyst).Acutedevelopment,afeverishstate,andairbronchogramappearancewithintheinfiltratehelpwiththedifferentiation,aswellastheregressionoftheinfiltratebytheendofthetherapy.ThemostcommonbacteriumisStreptococcuspneumoniae.Furtherimaging(CT)israrelynecessary.

7.Pneumatocelesintherightupperlobe. 8.Almostcompleteresolutionwithinonemonth.

9.aAtexpirationtherightsideisexpanded.

9.b.Atinspirationthemidlineisshiftedtotheright.Holzknechtsign:foreignbodyin

therightbronchus

18.2.4.Airwayforeignbody

Childrenputanythingintheirmouthand,thereforefromtimetotimeaccidentalaspirationstendtooccur.Thesymptomsofacuteaspirationareveryapparent.Apneumoniarecurringatcertainlocalizationishighlysuggestiveofchronicaspirationofaforeignbody.Hence,theroleofradiologyismoreimportantinchroniccasesofaspiration,wherepatienthistorydoesnotnecessarilyindicateforeignbodyaspiration.Xrayexamination:aspiratedforeignbodiesarerarelyXrayabsorbing,andthereforerarelyappearontheradiographs.AnegativeinspiratorychestXraydoesnotexcludethepossibilityofaFBaspiration.MostFBscauseocclusiononthelevelofthebronchi,whichmeansthatininspirationaircangetfurtherthantheFBbutatexpirationitwillblocktheairway.Thus,onexpiratorychestXray,theaffectedlungsegmentwillbepneumatic;thediaphragmwillbepushedlowerontheipsilateralside,whileatinhalationthemidlinewillbeshiftedtowardstheaffectedside(Holzknechtsign).InsuspicionofFBaspiration(evenifchestradiographisnegative)bronchoscopyiscompulsory.

18.3.Gastrointestinal(GI)tract18.3.1.Examinationmethods:

Preparation:Whenperformingapassageexaminationinnewbornsorsmallinfantsthelastfeedingisskipped.Astartingabdominalplainfilmradiographismandatorybeforeeachpassageexamination(toidentifythedistributionofintestinalgas,toruleoutfreeabdominalair,orintestinalwallpneumatizationandtolocatethelevelofobstruction.)Plainabdominalxrayisinmanycasesinformative,whethercontrastadministrationisreallynecessary,andifanimmediatesurgeryisunavoidable(e.g.:freeabdominalair,orincaseofaproximalatresiainnewborns).Incasesofcontrastexaminations(passageexamorcolonenema)thepreferredcontrasagenthasalowosmolalityandisabsorbable.

18.3.2.Afewimportantdiseases

Esophagealatresia:iscommonlylocatedattheleveloftheupper/middleesophagealborderandissometimesassociatedwithtracheoesophagealfistulas.Newbornsareunabletoswallowtheirsalivaandthediagnostictubegetsstuckintheesophagus.Themostcommonformisatresiawithalowerfistula.In50%ofthecasesotherabnormalitiesarepresent;aspartofthesocalledVACTERLsyndrome(vertebral,anal,cardiac,tracheoesophagealfistula,renalandlimb)variousadditionalabnormalitiescanbeobserved.Xrayexamination:anXrayabsorbenttubeisvisibleintheobstructeddiverticulaoftheesophagus.Incasesofalowerfistula,theintestinesareaerated,theaccompanyingcostalandvertebralabnormalitiescanalsobeobserved.Hypertrophicpyloricstenosis(HPS).Asaresultofthehypertrophyandhyperplasiaofthepyloricmusculatureasecondarystenosiscanoccur,thatusuallyleadstosymptomaticstatesin36weeksoldinfants.Itprimarilyoccursinboysasfrequent,progressive,nonbilious,projectilevomiting.Onultrasonographyanenlarged(15mmormore),thickwalled(3mmormore)pyloruscanbeseeninbothlongitudinalandinaxialcrosssection.

10.Thetubeinsertedintheesophagusturnsbackintheheightofthe4thThoracic

vertebra,theintestinesarefilled

withgas.Esophagusatresiawithlowerfistula.

11Thetubeinsertedintheesophagusturnsbackintheheight

ofthe2ndThoracicvertebra.Theabdomenis

gasless.Esophageal

atresiawithoutfistula.

12a:AbdominalUS:thepyloriccanalisextended,itswallisthickened.Pylorus

stenosis,longitudinalview.

12.b.Axialcrosssection.

Duodenalobstruction.Thecauseofproximalobstructionisprimarilyduodenalatresiaorstenosis.UsuallyUSisabletodepictthedistendedstomachandduodenumduringintrauterineUSexaminationasacysticmass,whileotherintestinesarecompletelyfreeoffluids.Vomitingoccursinthefirsthoursofextrauterinelife.Plainabdominalradiographincasesofatresiawillrevealthesocalleddoublebubblesign,wherethestomachandtheduodenumaredistendedbutondistalsegments,theintestinesaregasfree.Incasesofstenosis,thedistalintestinalloopswillalsoshowsomeaircontent.Otherexaminationsareunnecessaryandaircanbeusedasanegativecontrastmaterial.Malrotationvolvulus.Duringthenormaldevelopmentoftheintestinaltract,theintestinalloopsmakethree90degreeclockwiserotationsaroundthemesentericsuperiorartery(MSA.)Ifthisrotationonlypartiallyoccursduringtheembryonicdevelopmenttheintestinesremaininanonrotationalormalrotationalposition,themesentericrootwillbeshorterandthececumwillbeweaklyattached.Thisanatomicpositioningcanbesymptomfreethroughoutalifetime,butitpredisposesforvolvulus.Volvuluscanoccuratanyage,butitismostfrequentinthefirstmonthsoflife,whenitabruptlyoccurswithacutebiliousvomiting.Inthisstatetheintestinesaroundthemesentericroottwist,endupinacompleteobstructionthatcanleadtoarapiddeathoftheintestines.Ultrasonographycandepictthemesentericsuperiorvein(MSV)coileduparoundtheMSA,socalledwhirlpoolsign.DuringXrayexaminationthecontrastmaterialdoesnotprogresstothejejunalloopsoritshowsacorkscrewsignontherightsideofthevertebraeasitpilesupin

thetwistedintestinalloops.

13.Distendedstomachandduodenalbulbus,Doublebubblesign.Duodenal

atresia.

14.WhirlpoolsignThemesenteryandthesuperiormesentericvein,asitcoilsaroundthesuperior

mesentericartery.Volvulus.USexam.

15.Contrastmaterialemptiesthestomachslowly,smallintestinesarefoundontherightsideoftheabdomen.Malrotationvolvulus.

16.Nonused,narrowcolon.Newborn,meconium

ileus

Meconiumileusoccursin10%ofchildrenwithcysticfibrosis(CF),andalmostallofmeconiumileuscasesarearesultofCFdisease.Itischaracterizedbyvomitingandabdominaldistention,asthemeconiumcannotbedefecated.Onplainabdominalradiographtheintestinesaredistendedwithoutanyairfluidlevelsduetotheadhesivenatureofmeconium.Colonenemaexaminationwithwatersolublecontrastmaterialwillshowamicrocoloninwhichthemeconiumwillcausecontrastfillingdefectsresemblingsmallpearls.Contrastmaterialthatreachestheterminalileum,andtherepetitionoftheenemascansometimessolvetheileus.Invagination.Adistalintestinalloopinvaginatingtoaproximalintestinalloopcanresultinamechanicalintestinalobstruction,andcauseischemicdamage.Itmostfrequentlyoccursininfants(324months)withrecurring,coliclikecomplaints,distendedintestines,apalpablemassandwithfrequentvomitingandbloodystool.Invaginationrequiresimmediatediagnosisanddesinvagination.USexamrevealstheinvaginatedintestinesasatargetsigninaxialcrosssectionandlookslikeapseudokidneyinlongitudinalcrosssection.Thetherapyishydrostaticorpneumaticdesinvagination.Perforationand/orperitonitisareabsolutecontraindicationstotheseprocedures.HydrostaticdesinvaginationcanbeperformedunderfluoroscopyorwithUSguidanceandisconsideredsuccessfulifairorthecontrastmaterialappearsintheterminalileumandtheinvaginatedloopdisappears.Iftheseeffortsdonotsucceed,surgicaldesinvaginationisneeded.

17.Targetsign.Invagination.. 18.abcDesinvaginationwithair.

18.b.Arrow:invaginatedsegment.

18.c.Successfuldesinvagination

Necrotizingenterocolitis(NEC).Itisasevereintestinalnecrotizingdiseaseofthenewborns.Itusuallyoccursasearlyasthefirst10daysoflife,butcanhappeninthefirstfewmonthsafterbirth.Vomiting,distendedintestines,bloodystool,acidosis,peritonitisandperforationarefrequentfindings.PlainabdominalXraycanbenoninformativeintheearlystagesofthedisease;laterdistensionindicatestheseparationofloopsduetowallthickening.Often,airbubblesappearintheintestinalsubserosalorsubmocosallayers,ascharacteristicsignsofintestinalpneumatosis.Theintramuralaircandiffusetothemesentericveinsandappearintheportalcirculationintheprojectionoftheliver.Freeabdominalairisindicativeofperforationandrequiressurgicalintervention.USexaminationcanrevealthesecharacteristicsofthediseasebeforeXrayisindicative.UScandepictthickenedintestinalwall,portalandintramuralair,abdominalfreefluidorabscesses.Hirschsprungdisease.Inthisdiseasetheganglionsofthedistalcolonaremissing.Thelackofinnervationofthecolonicsmoothmuscleresultsinspasticfunctionalobstruction.Thesymptomscanappearrightafterbirthwiththelackofmeconiumdefecationandsignsofobstruction.OnplainabdominalXraytheproximalintestinesaredistendedwithorwithoutairfluidlevels,thedistalloopsaregasfree.Withcontrastenemathedistal,irregular,spastic,noninnervatedsegmentsandtheproximalprestenoticdilatationofthecoloncanbevisualized.

19.Distendedbowelloops.Airisseenintheintestinalwall,

intestinalpneumatosis.Necrotizingenterocolitis.

20.NEC,USexamination.Freeabdominalfluid,withdense

innerechos.Airbullblesintheintestinalwall:zebrasign

(arrow).

21.Thedistalsegmentofthecolonisnarrow,irregular

(aganglionarsegment).Transitionalzone(arrow)

andcompensatoryprestenoticdilatation.Hirschsprungdisease.

18.4.Urogenitalsystem18.4.1.Diagnosticmethods

Ultrasoundisthemethodofchoice,providesdetailedinformationofthemorphologyofthekidneysandtheurinarytract.Prenatalexaminationscanreadilydiagnosemostofthelesionsattheintrauterineage.Mictioncystourethrography(MCU).Isthegoldstandardfortheimagingofthebladderandthedistalurinarytractsaswellastheinvestigationofvesicouretralreflux.Aurinarycatheterisinsertedandcontrastagentisadministeredwithfluoroscopiccontrol.Sonocystography.Ultrasonographiccontrastmaterialisadministeredtothebladderthroughacatheter.Thecontrastmaterialincreasestheechogenityoftheurine(fluid)andincasesofrefluxthischangecanbedetectedintheureterandthepyelon.ThismethodinmostcasescansubstituteMCU,however,theurinarycatheterstillremainsaninvasivestepoftheexamination.Nuclearmedicineexaminations(seethere)MRurography(seethere)

18.4.2.Someimportantdiseases

Congenitalobstructiveuropathies.Congenitalabnormalitiesofkidneydevelopmentcanoccuratanyleveloftheurinarytract.Itsmostcommonsingisurinarytractdilatation.Theroleofimagingisin:diagnosingthecause,thelevelandthestageofdilatationanddifferentiatingtheobstructivecasesformnonobstructiveones.Uretropelvicobstruction(UPO).Uretropelvicjunctionstenosiscanbeanacquiredoraninnatestate,withdifferentdegreesthatleadtothedysfunctionofexcretionofurinefromthepyelontotheproximalureter.Itisthemostfrequentformofobstructiveuropathy.USexaminationevenatprenatalstatescandiagnosetheurinarytractdilatationthatcanbeuniorbilateral,alwayswithoutureterdilatation.Isotopeexamination:theisotope(Tc99mMAG3)injectedwithdiureticscanbeusedtoanalyzerenalfunction.Distalurethralvalve(subvesicalobstruction).Itisthemostsevereformofobstructiveuropathy.Innewbornboysthevalvedysfunctioncanleadtobilateralobstructionwithhydronephrosisandhydroureter.Urinationcanonlyoccurintermittently.Thebladderwallisthickened,trabecularandrefluxisfrequent.Theproximalurethraisdistendedaswell.

22.Thecalicesandthepyelonofthekidneyaremarkedlydilated,theparenchymais

thinner.Severehydronephrosis.Theureterisnotvisible.Pyelouretralstenosis.

23.Mictioncystourethrography.Asmalldiverticulaisseenontherightside,theproximalurethraisdilated,beneathisafilling

defect.Subvesicalobstruction,dorsalurethral

valve.

Vesicouretral(VU)reflux.Refluxstandsforthereentryofurinefromthebladdertotheureterandthecollectingsystemofthekidneysduetotheinsufficiencyoftheuretrovesicalvalve.Thiscanleadtoatransientorapermanentdilatationoftheurinarytracts.UScanonlyraisesuspicionforUVrefluxthroughindirectsignssuchasthickenedpyelonwall,smallkidney,thinnerandblurrycorticomedullaryjunction,unevenparenchyma,thickenedbladderwall.RefluxcanbedepictedwithMCUorsonocystogrphy.Refluxisinternationallycategorizedin5levels(IV).Itsspecialformistheintrarenalrefluxthatappearsintheupperorlowerpoleofthekidney.

24.a. 24.b. 24.c. 24.d. 24.e.

Mictioncystourethrography.a.Refluxintheleftnormaldiameterureter.VURl.s.Gr.I.b.Bothuretershaveanormaldiameterastheyrefillwiththecontrastmaterialrefluxingfromthebladder.VURl.u.Gr.II.c.Thereisaslightlydilatedrightureterandcollectingsystemintherightkidney,thecalicesarewidened.VURl.s.Gr.III.d.Dilatedureterandcollectingsystemcanbeseenontheleftside.VURl.s.Gr.IV.e.Therightureterismarkedlydilatedandelongatedthepelvicalycealsystemisalsomarkedlydilated,thecalicesarerounded,contrastmaterialappearsinthetubulesaswell.VURl.d.Gr.5.withintrarenalreflux.

18.5.Abdominalmasses

Neuroblastoma.isatumorthatdevelopsatanypartofthesympatheticnervoussystem.Therefore,inover90%ofthecasestheurinarycatecholaminelevelsareelevated.Itisthemostfrequentextracranial,solidtumorinchildrenandhasitshighestmalignancyratewithinthefirstyear.Itismostcommoninchildrenaged15years,appearsasapalpableabdominalmass,withfever,hypertension,andanemia;incasesofbonemetastases,bonepainandlimpingarecommon.USexaminationrevealsawellcircumscribed,echogenicmassusuallycrossingthemidline,dislocatingthekidney;itisfrequentlycalcified,highlyvascular,surroundingandcompressingtheabdominalvessels.Inprogressivecasesliverandnodalmetastasescanbefound.Thetumorcanalsobesolid,homogenousandwithasmoothmargin.TheadrenalregioninnewbornsiswellvisualizeablewithUS,butatolderagesonlymajorlesionscanbedepicted.CT/MRIexamination:candepictalargesized,irregularshaped,extrarenalmass,withfrequentnecrosis,hemorrhageandcalcifications.Thelesionsshowaheterogeneouscontrastenhancement.Nuclearmedicineexamination:MIBGscintigraphyisbasicallya100%specificbutitssensitivityislower,becausenonMIBGuptakingtumorsexistaswell.

25.USexamination,longitudinalview.Abovetherightkidney,intheadrenalregionasolid,slightlyinhomogeneousmasscanbeseen.

Neuroblastoma.

26.MRIexamination,axialT2weightedimage.Irregular,largesolid,inhomogeneousretroperitonealtumorisseen.Neuroblastoma.(withthe

courtesyofDr.GborRudas)

Wilmstumor.Itisthemostcommonkidneytumorinchildhoodthatappearsbetween25yearsofage.Itisusuallyonlynotedwhenthetumorispalpableasanabdominalmass.Hematuria,hypertension,vomitingandabdominalpainarealsopartoftheclinicalpicture.USexaminationisabasicmethodinboththediagnosticsandthefollowupofthetumor.Thetumorisnormallyseenasahomogenousoraninhomogeneousmass,dislocatingthepyelonandthesurroundingretroperitonealbloodvessels.Itisimportanttoruleoutanylesionintheotherkidney.MRIexamination:givesapictureoftheentireabdomen,kidneysincluded.Nodalmetastases,tumorthrombusarewelldepictable.CTexamination:istobechosenifMRIisnotavailable.Thetumorshowsaninhomogeneouscontrastenhancementandpulmonarymetastases(invisibletoxrayexamination)arealsodepictable.

27.Asolid,echogenicmassarisingfromtherightkidney.Wilmstumor.AbdominalUS.

28.MRIexaminationaxial,T2weightedsequence.Asolidmassarisingfromtherightkidneyandfillingouttheright

29.CTexaminationafteriv.contrastadministration.Mostlyhypodensemassarisingfromtheleftkidney.

sideoftheabdomen,withperipheralfollicularcysticcomponents.Wilmstumor.(withthecourtesyofDr.

GborRudas)

Wilmstumor.(withthecourtesyofDr.Z.Kardi)

18.6.Centralnervoussystem(CNS)

Duetothevastnessofthisfield,inthissegmentwecanonlyconsidersomefundamentallydifferentdiagnosticmethodsandafewCNSdiseasestypicaltonewbornsandinfants.ThemostimportantdiagnosticmethodoftheCNSofinfantsandchildrenisMRI.(seethere)

18.6.1.Specialimagingmethodsofnewbornsandinfants

Cranialultrasonography:isthefirstmethodofchoiceinbrainparenchymaexaminations.Itcanonlybeperformeduntiltheclosureofthefontanelles(810months)(anteriorandposteriorfonatnelles,mastoidalandtemporalregion).Examinationsrequireahighfrequencyconvextransduceraswellasalinearone.Vertebralultrasound:canonlybeperformedinthefirst23monthsoflifeuntiltheclosureofthevertebralarch,withalineartransducer.

30.a. 30.b. 30.c. 30.d.

30.ad)Cranialultrasound.Normalnewbornbrain.ab.Coronal,cd.Sagittalviews.

USexaminationisalsocapableofdiagnosingandfollowingupcerebralcomplicationsofprematureinfantse.g.:germinalmatrixhemorrhage,periventricularleukomalacia(PVL),hydrocephalusandforthescreeningofcertaindevelopmentaldisorders(corpuscallosumagenesis,Galeniveinaneurysm,DandyWalkersyndrome).However,wehavetorememberthatUSisnotsensitivetoallabnormalitiesormoresophisticatedlesions.Metabolicdiseasesandsomehemorrhagesetc.arenotalwaysdetectablewithUS.ItisaveryusefulmethodbutitslimitationshavetobekeptinmindandwhennecessaryMRIistobeused.

31.NormalspinalUS,longitudinalview(longarrow:medullarcone,smallarrowvertebralbody.)Newborn.

32.USexamination,sagittalview.Radialpatternofthegyri.Corpuscallosumagenesis

33.a.USexamination,coronalview.Ontherighttemporallobeasmallechogenicarea

canbeseen.

33.b.MRI,axialview,diffusionsequence.Rightsided,3.5cmarea

withrestricteddiffusion.Acuteinfarctintheparietotemporalregion.(SE,

MRKK,withthecourtesyofdr.GyrgyVrallyai).

33ab.Cerebralinfarct,newborn.

18.6.2.Somediseasesofpreterminfants

Germinalmatrixhemorrhage.Itisahemorrhagetypicallyoccurringinprematureinfants.Thereare4stagesdistinguished(subependymalbleeding,ventricularhemorrhage,ventricularbleedingwithhydrocephalus,andthelatter+parenchymableeding).Hydrocephaluscanbeafrequentcomplicationaftergerminalmatrixhemorrhage,butatabouthalfofthecasesitresolvesspontaneously.USexaminationisamethodforitsdiagnosticsandalsoforitsfollowup.Periventricularleukomalacia(PVL).Itisusuallyabilateralporenchephaliccysticdiseaseintheperiventricularwhitematterthatdevelopsduetoischemicdamageinpreterminfants.

34.CranialUS,coronalview.Moderateventriculardilatationwithinhomogeneous

bleedingintheventralhornoftherightlateralventricle.GradeIII.hemorrhage.

35.CranialUS,coronalview.Theposteriorhornsaredilated,hemorrhageispresentinall

ventricles.Leftsidedperiventricularparenchymableeding.GradeIV.hemorrhage.

36.CranialUS,sagittalview.Dilatedventricle,periventricularcysts.PVI.

18.6.3.Maturenewborns

Hypoxicischemicencephalopathy(HIE).Hypoxicischemia,orperinatalasphyxiaisthemostcommoncauseforsevereneurologicabnormalitiesofthenewborns.Theroleofimagingistodeterminethegradeandextentofthedamageandtomonitorthedamagedlesionasearlyaspossible.Ultrasonography:insomecasesintheacutestagesofthediseasecanvisualizefocalordiffusehyperechogenicperiventricularorbasalganglialesions.Inchronicstagesperiventricularcysts,encephalopathy,hydrocephalusandwidenedsubarachnoidspacecanbedetected.MRIexaminationisthemostsensitivemethod,asitcandepictchangesundetectablebyUS.IntheacutestageMRspectroscopyisverysensitivetothedamagethatisindicatedbylactatepeakandadecreaseinothermetabolites.Diffusionweighedimagingisthemostsensitivewaytodetectcytotoxicedemarightaftertheischemicinsult.

18.6.4.DevelopmentaldisordersoftheCNS

Theyareamongstthemostcommondevelopmentaldisorders(1:100births).Thespectrumisbroad,coveringsmall,focalcorticaldysplasiaaswellascomplexsyndromes.Theearlydetectionofthesedevelopmentaldiseaseshelpsindeterminingthedegreeofthelesionandmighthelpinthetherapy,aswellasintheprognostics.Itplaysafundamentalroleintheplanningoffuturepregnancies.USexaminationisonlygoodforpartialdiagnostics;MRIisthebestchoiceforthedetectionofcorticalmalformations,migrationalanomaliesandmyelinationdisorders.

18.6.5.Supraandinfratentorialbraintumorsinchildren

Brainneoplasmsarethesecondmostcommontumorsinchildren,afterleukemia.Theirsymptomsdifferfromtheonesofadulthood,ononehandbecauseweencounterdifferenttypesoftumorsinchildrenandontheotherbecausethebonysuturesarestillnotclosedinthisagegroup.Braintumorsbelowtheageof2tendtobeprimarilysupratentorialinlocalization,whileinagesbetween2and10yearstheyaremostlyinfratentorial.Above10yearsofagethesupraandinfratentorialtumorratioisbasicallythesame.BeforebrainsurgeryMRIexaminationisperformedwithvarioussequencesandiv.contrastadministration,moreoverfunctionalMRIexamsmightbeusedascomplementarytechniquestohelpthecorrectdiagnosisandsurgicaldecisionmaking.Earlyphase(24hours)postoperativeMRIiscapabletoshowresidualtumors.USexaminationisoflimitedvalue,itcanbeusedinthefollowupofconsequentialhydrocephalus.

18.7.Musculoskeletalsystem

18.7.1.Diagnosticmethods(seethere)

18.7.2.Someimportantdisorders.

Osteomyelitis.Osteomyelitisstandsfortheinflammationoftheboneandthebonemarrow.Itsmostimportantsymptomsarefever,pain,erythema,swellingandelevatedinflammatorylabparameters.Innewbornsandpreterminfantsitisoftensymptomfreeandmultifocal.Earlydiagnosticsandtherapyareextremelycrucial,sincethedevelopingbonesmightsufferapermanentdamage.Under1yearofagetheepiandmetaphysisarerichinbloodvesselanastomosesthatprovideaspreadingroutefortheinflammationtowardstheepiphysisoreventothejointsortheadjacentbone.After1yearofagetheanastomoticconnectionsdisappearandthediseaseischaracteristicallymetaphyseal.Rarely,butprimarydiaphysealandepiphysealosteomyelitiscanalsooccur.Xray:doesnotshowanychangeswithinthefirst714days.Thefirstsignisfocal,unevenporosis.Infurtherstagessofttissueswelling,bonydestruction,osteolysis,bonenecrosiscanoccurandevenlater,sequestrationandperiostealreactiontakesplace.Radiologichealingtakesmonths.Ultrahasonography:detectsearlysignsbeforeXrayexaminationdoes.Itcanquicklydepictsofttissueedema,periostealreactionandsubperiostealfluids.Nuclearmedicine:offersamethodwitha90%andupsensitivityandspecificitytoosteomyelitis,howeverwithinthefirst6monthsoflifeisonlypartiallyreliableinthediagnostics.Itshowsacharacteristicactivityincreaseinall3stagesoftheexamination.MRI:candetectosteomyelitisinearlystages,andwithgreatreliability.Itsrateforidentificationandthedetectionoftheextentofthediseaseisbetween88100%.MRIisabletoprovideagoodpictureofthephysis,epiphysisandtherelationoftheinflammationtothejointaswell(edema,exudates,abscess).

37.a. 37.b. 37.c. 37.d.

37.ad)Xrayoftherighthumerus.a.Rarefactionintheproximalmedialpartofmetaphysisoftherighthumerusearlyosteomyelitis.b.Twoweeksafterthelyticareahasgrown.c.1monthlaterscleroticregenerationhasbegun.d.4monthsafteralmostcompletehealing.Osteomyelitis,infant.

38.US,longitudinal.Ontheproximalpartoftherightfemur,theperiostealsofttissueis

hypoechoic,theflowisincreased.Osteomyelitis

39.a. 39.b.

39.ab.MRI,T2weightedandT1weighted,postcontrastaxialimages.Signalintensityincreaseandincreasedcontrastenhancementinthebonemarrowoftheleftfemoralneck,.2yearsoldchild,osteomyelitis.(withthecourtesyofdr.GborRudas).

Transitorycoxitis.Itisatransitionalinflammatorydiseaseofthehipjointthatcausespainandlimping.Thepainismanytimeslocalizedelsewhere;onthelimbortheknee,leavinglimpingasanonlysymptom.USexamination:candepictsmallamountsoffluid.Eithera4mmwidefluidcollectionor2mmdifferencecomparedtotheotherlegareindicativeofinflammation.Thesynoviumisoftenthickened.

Rachitis.RachitiscanbecausedbyinsufficientvitaminDalimentation,adecreaseinmineraluptake(e.g.:prematureinfants)andvitaminDshortageduetomalabsorption(coeliakia,cysticfibrosis)oradisorderinvitaminDproductionprocess.Itsclinicalsymptomsareverycharacteristic:thewristisswollen,apalpablemassorstrainisoftenfoundontheanteriorachoftheribs,theskulliscompressiblelikeapingpongball.Xrayexamination:thetypicalsignsofrachitiscanalwaysbefoundinthetransitionalossificationzone.Onwristradiographthedistalmetaphysisoftheulnaandtheradiushaveanirregularcontour,theyarehollowed,thedistancebetweentheboneandtheepiphysealcoreiswidened.Rntgenfelvtel:acsipdysplasiaacsontosfemurfejmagjnakmegjelensigcsakindirektjelekbldiagnosztizlhat.

40.WristXray.Thedistanceofthewrist

bonesandradial/ulnarepiphysisiswidened,unevenandhollowed,atpartsthebone

densityisdecreased.Rachitis

41.USexamination,hip,longitudinalview.Thelefthipsarticularspaceiswidened,withecho

freefluidinit.Transitorycoxitis.

42.USexamination.Normalnewbornhip(arrow:hipbone.)

Hipdysplasia.Congenitalhipdysplasiaisamultifactorialdiseasethatoccursmoreingirls(1:9)andcausesthedislocationoftheheadofthefemur.Acetabularrimdevelopmentandconfigurationabnormalities,ligamentlooseness,musclecontracture,familyhistoryofhipdysplasia,orintrauterinebreechpositionhaveallbeenmentionedaspossiblefactorscausinghipdysplasia.USexaminationiscapabletodiagnoseinfanthipdysplasia.Itisindicatediftheclinicalexaminationraisessuspicionorifriskfactors(breechposition,twinpregnancy,familyhistory,oligohydramnion,deformedlimb,neuromusculardisease)persist.UScanbeusedasascreeningtool.Duetothephysiologicloosenessoftheligamentsbefore4weeksofagethehipisimmature,thereforescreeningexamshouldtakeplaceafter4weeksandcanbeperformeduntil46months.Xrayexam:canonlydetectindirectsignsofhipdysplasiauntiltheappearanceoftheossificationcentersofthefemoralhead.Batteredchild,childabuse,shakenbabysyndrome,nonaccidentalinjury.Theseareallsynonymsdescribingthesyndromeofchildabuse(usuallyofnewbornsandinfants).Atmanytimesonlytheradiologistcanidentifythesecases.Therearesomecharacteristicinjuriesthatarenotinrelationwiththestorytheparentstell.Fracturesofmultiplenumbers,orinvarioushealingstagesareindicativeofchildabuse.Complexskullfracturesarerareinsimplecasesoffalling.Themostcharacteristicsingsaremetaphysealorcornerfracturesonthemetaphisesofthetubularbones.Violentshakingcausesribfracturesandthetoandfromotionoftheheadleadstosubduralhematomas,hypoxiedematouscontusion.Xrayexamination:chest,bidirectionalskull,vertebralandlimbradiographsarenecessary.USexamination:bothcranialandabdominalUSareperformedininfants.CTexaminationcanberequirediftheabdominalorthevertebralinjuriesaresevere.MRIisunavoidableifneurologicsymptomspersist.

43.ComparisonRadiographoftheknees.Onthedistallateralepiphysisoftherightfemurcornerfractureisseen,lyticarea,periostealreaction.Bothproximaltibia,

onthevisiblepartofthepictureshowperiostealreaction.Batteredchild.

Summary

1.ALARAAsLowAsReasonablyAchievable,atermfortheuseofaslowradiationdoseaspossible.Itisafundamentalandprimarypointofviewinpediatric

radiology.2.DiseasesofthechestcanmostcommonlybediagnosedwithXray,andcomplementaryUSexaminations.CT/MRIisrarelynecessary.3.Airintheimagingofgastrointestinaldevelopmentaldiseasecanoftenbeusedasanegativecontrastmaterialonplainabdominalxrays,andissufficientfordiagnosis.4.TheinvestigationoftheGItractofthenewbornsiscarriedoutbylowosmolality,absorbablecontrastmaterials.USexaminationsareimportantpartofthediagnostictoolkit.5.US,mictioncystourethrography,nuclearmedicineandrarelyMRIareneededinthediagnosticsofurinarytractdisorders.6.CranialandvertebralUSexaminationshavesomelimitations,butareusefuldiagnosticmethodswhilethefontanellasandthevertebralarchareopen.IftheUSexaminationisnotsatisfactorytheCNSshouldbeexaminedwithMRI.