Hand Bone Age: A Digital Atlas of Skeletal Maturity PDF
Preview Hand Bone Age: A Digital Atlas of Skeletal Maturity
V.Gilsanz/O.Ratib·HandBoneAge Vicente Gilsanz · Osman Ratib Hand Bone Age A Digital Atlas of Skeletal Maturity With88Figures VicenteGilsanz,M.D.,Ph.D. DepartmentofRadiology ChildrensHospitalLosAngeles 4650SunsetBlvd.,MS#81 LosAngeles,CA90027 OsmanRatib,M.D.,Ph.D. DepartmentofRadiology DavidGeffenSchoolofMedicineatUCLA 100MedicalPlaza LosAngeles,CA90095 ISBN3-540-20951-4Springer-VerlagBerlinHeidelbergNewYork LibraryofCongressControlNumber:2004114078 Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthe materialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations, recitation,broadcasting,reproductiononmicrofilmorinanyotherway,andstorageindata banks.Duplicationofthispublicationorpartsthereofispermittedonlyundertheprovisions oftheGermanCopyrightLawofSeptember9,1965,initscurrentversion,andpermissionfor usemustalwaysbeobtainedfromSpringer-Verlag.Violationsareliabletoprosecutionunder theGermanCopyrightLaw. Springer-VerlagBerlinHeidelbergNewYork SpringerisapartofSpringerScience+BusinessMedia http://www.springeronline.com A Springer-VerlagBerlinHeidelberg2005 PrintedinGermany Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublication doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. Productliability:Thepublisherscannotguaranteetheaccuracyofanyinformationaboutthe applicationofoperativetechniquesandmedicationscontainedinthisbook.Ineveryindividu- alcasetheusermustchecksuchinformationbyconsultingtherelevantliterature. CoverDesign:eStudioCalamar,Spain Typesetting:FotoSatzPfeiferGmbH,D-82166Gräfelfing Printedonacid-freepaper–21/3150–54 3210 Table of Contents Introduction ................................................. 1 BoneDevelopment............................................ 2 ClinicalApplicationsforSkeletalDeterminations .................. 3 ConventionalTechniquesforSkeletalDeterminations .............. 5 ComputerAssistedTechniquesforSkeletalDeterminations.......... 8 IndicatorsofSkeletalMaturityinChildrenandAdolescents ........ 9 Infancy...................................................... 10 Toddlers..................................................... 11 Pre-puberty .................................................. 12 EarlyandMid-puberty ........................................ 14 LatePuberty ................................................. 15 Post-puberty ................................................. 16 DigitalBoneAgeAtlas......................................... 18 Subjects ..................................................... 18 MethodsandTechniques ....................................... 18 ValidationofStandardsandTechnique ........................... 21 SoftwareUserManual ......................................... 23 SoftwareInstallation .......................................... 25 ReferenceImages Boys ........................................................ 35 Girls ........................................................ 64 Tables ....................................................... 93 References ................................................... 96 Acknowledgement Thisatlaswouldnothavebeenpossiblewithouttheexceptionalcontribu- tionsofDoctorsMariaInesBoechatundXiaodongLiu,whopainstakingly helped in the review, interpretation and assessment of hundreds of hand andwristradiographs. Introduction Boneageassessmentisfrequentlyperformedinpediatricpatientstoevalu- ategrowthandtodiagnoseandmanageamultitudeofendocrinedisorders andpediatricsyndromes.Fordecades,thedeterminationofbonematurity hasreliedonavisualevaluationoftheskeletaldevelopmentofthehandand wrist,mostcommonlyusingtheGreulichandPyleatlas.Withtheadventof digitalimaging,multipleattemptshavebeenmadetodevelopimage-pro- cessing techniques that automatically extract the key morphological fea- turesofossificationinthebonestoprovideamoreeffectiveandobjective approachtoskeletalmaturityassessments.However,thedesignofcomput- eralgorithmscapableofautomaticallyrenderingboneagehasbeenimped- edbythecomplexityofevaluatingthewidevariationsinbonemineraliza- tiontempo,shapeandsizeencompassedinthelargenumberofossification centersinthehandandwrist.Clearly,developinganaccuratedigitalrefer- ence that integrates the quantitative morphological traits associated with thedifferentdegreesofskeletalmaturationof21tubularbonesinthehand and8carpalbonesinthewristisnotaneasytask. Inthedevelopmentofthisdigitalatlas,wecircumventedthedifficulties associatedwiththedesignofsoftwarethatintegratesallmorphologicalpa- rametersthroughtheselectionofanalternativeapproach:thecreationof artificial, idealized, sex- and age-specific images of skeletal development. Themodelsweregeneratedthroughrigorousanalysesofthematurationof eachossificationcenterinthehandsandwristsofhealthychildren,andthe constructionofvirtualimagesthatincorporatecompositesoftheaverage developmentforeachossificationcenterineachagegroup.Thiscomputer- generatedsetofimagesshouldserveasapracticalalternativetotherefer- encebookscurrentlyavailable. Bone Development Skeletalmaturityisameasureofdevelopmentincorporatingthesize,shape anddegreeofmineralizationofbonetodefineitsproximitytofullmaturi- ty.Theassessmentofskeletalmaturityinvolvesarigorousexaminationof multiplefactorsandafundamentalknowledgeofthevariousprocessesby whichbonedevelops. Longitudinalgrowthinthelongbonesoftheextremitiesoccursthrough the process of endochondral ossification. In contrast, the width of the bones increases by development of skeletal tissue directly from fibrous membrane.Thelatteristhemechanismbywhichossificationofthecalvari- um,theflatbonesofthepelvis,thescapulae,andthebodyofthemandible occurs.Initialcalcificationbeginsnearthecenteroftheshaftoflongbones inaregioncalledtheprimaryossificationcenter[1]. Although many flat bones, including the carpal bones, ossify entirely fromthis primarycenter, allof the long bonesdevelopsecondary centers that appear in the cartilage of the extremities of the bone. Maturation in thesecentersproceedsinamanneridenticaltothatintheprimarycenters Fig.1.Schematicrepresentationofendochondralboneformation.Skeletalmaturityismainlyas- sessedbythedegreeofdevelopmentandossificationofthesecondaryossificationcentersinthe epiphysis ClinicalApplicationsforSkeletalDeterminations 3 with ossification of cartilage and invasion of osteoclasts and osteoblasts. Theboneossifiedfromtheprimarycenteristhediaphysis,whilethebone ossifiedfromthesecondarycenteristheepiphysis.Asthesecondarycenter isprogressivelyossified,thecartilageisreplacedbyboneuntilonlyathin layerofcartilage,theepiphysealplate,separatesthediaphysealbonefrom the epiphysis. The part of the diaphysis that abuts on the epiphysis is re- ferredtoasthemetaphysisandrepresentsthegrowingendofthebone.As longastheepiphysealcartilageplatepersists,boththediaphysisandepiph- ysiscontinuetogrow,but,eventually,theosteoblastsceasetomultiplyand theepiphysealplateisossified.Atthattime,theosseousstructuresofthe diaphysisandepiphysisarefusedandgrowthceases[1]. Inthefetalphaseoflife,theprincipleinterestinskeletalgrowthisassoci- ated with the diagnosis of prematurity. The end of the embryonic period andthebeginningofthefetusismarkedbytheeventofcalcification,which beginsat8or9weeks.Bythe13thfetalweek,mostprimarycentersofthetu- bular bones are well-developed into diaphyses, and, at birth, all diaphyses arecompletelyossified,whilemostoftheepiphysesarestillcartilaginous. Ossification of the distal femoral epiphysis begins during the last two monthsofgestation,andthissecondarycenterispresentinmostfullterm babies.Similarly,theossificationcenterfortheproximalepiphysisofthehu- merususuallyappearsaboutthe40thweekofgestation.Ontheotherhand, thecentersfortheproximalepiphysesofthefemurandtibiamaynotbepre- sentinfullterminfants,butappearinthefirstfewmonthsoflife[2,3]. Afterbirth,theepiphysesgraduallyossifyinalargelypredictableorder, and,atskeletalmaturity,fusewiththemainbodyofthebone.Comparing thedegreeofmaturationoftheepiphysestonormalage-relatedstandards forms the basis for the assessment of skeletal maturity, the measure of whichiscommonlycalled“boneage”or“skeletalage”.Itisnotclearwhich factorsdetermineanormalmaturationalpattern,butitiscertainthatge- netics, environmental factors, and hormones, such as thyroxine, growth hormone, and sex steroids, play important roles. Studies in patients with mutations of the gene for the estrogen receptor or for aromatase enzyme havedemonstratedthatitisestrogenthatisprimarilyresponsibleforulti- mateepiphysealfusion,althoughitseemsunlikelythatestrogenaloneisre- sponsibleforallskeletalmaturation[4]. ClinicalApplicationsfor Skeletal Determinations Asinglereadingofskeletalageinformstheclinicianoftherelativematurity ofapatientataparticulartimeinhisorherlife,and,integratedwithother clinicalfindings,separatesthenormalfromtherelativelyadvancedorre- 4 BoneDevelopment tarded.Successiveskeletalagereadingsindicatethedirectionofthechild’s developmentand/orshowhisorherprogressundertreatment.Innormal subjects,boneageshouldberoughlywithin10percentofthechronologi- calage.Greaterdiscordancebetweenskeletalageandchronologicalageoc- cursinchildrenwhoareobeseorwhostartpubertyearly,astheirskeletal ageisaccelerated. There aretwomainapplicationsfor evaluationsofskeletalmaturation: thediagnosisofgrowthdisordersandthepredictionoffinaladultheight. DiagnosisofGrowthDisorders Assessments of skeletal age are of great importance for the diagnosis of growth disorders, which may be classified into two broad categories with differentetiologies,prognosesandtreatments.Primarygrowthdeficiency isduetoanintrinsicdefectintheskeletalsystem,suchasbonedysplasia, resulting from either a genetic defect or prenatal damage and leading to shorteningofthediaphysiswithoutsignificantdelayofepiphysealmatura- tion. Hence, in this form of growth disorder, the potential normal bone growth(andtherefore,bodygrowth)isimpaired,whileskeletalageisnot delayedorisdelayedmuchlessthanisheight. Secondarygrowthdeficiencyisrelatedto factors, generallyoutside the skeletal system, that impair epiphyseal or osseous maturation. These fac- torsmaybenutritional,metabolic,orunknown,asinthesyndromeofidio- pathic (constitutional) growth delay. In this form of growth retardation, skeletalageandheightmaybedelayedtonearlythesamedegree,but,with treatment,thepotentialexistsforreachingnormaladultheight. The distinction between these categories may be difficult in some in- stances in which skeletal age is delayed to a lesser degree than height. In general, however, differentiation between primary and secondary catego- riesofgrowthfailurecanbedeterminedfromclinicalfindingsandskeletal age[5]. FinalHeightPredictions The adult height of a child who grows up under favorable environmental circumstancesis,toalargeextent,dependentonheredity.Thefinalheight of the child may, therefore, be postulated from parental heights. Indeed, variousmethodsoffinalheightpredictions,whichtakeintoaccountparen- talheight,havebeendescribed[6].Achild’sadultheightcanalsobepre- dictedfromhisorherheightsatearlierages,withcorrelationsontheorder of0.8.However,childrendiffergreatlyinrateofdevelopment;someattain maturityatarelativelyearlyage,whileothershaveaslowtempoandfinish
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