www.bjorl.org
Brazilian
Journal
of
OTORHINOLARYNGOLOGY
ORIGINAL
ARTICLE
Are
computed
tomography
3D
measurements
of
the
upper
airways
in
mouth-breathing
children
in
agreement
with
the
ENT
clinical
diagnosis
of
obstruction?
夽
Bruno
César
Ladeira
Vidigal
a,
Carolina
Morsani
Mordente
a,
Paula
Loureiro
Cheib
a,
Flávio
Ricardo
Manzi
b,
Letícia
Paiva
Franco
c,∗,
Helena
Maria
Gonc
¸alves
Becker
d,
Bernardo
Quiroga
Souki
baPontifíciaUniversidadeCatólicadeMinasGerais(PUC-Minas),ProgramadePós-Graduac¸ãoemOdontologia,BeloHorizonte,MG,
Brazil
bPontifíciaUniversidadeCatólicadeMinasGerais(PUC-Minas),Odontologia,BeloHorizonte,MG,Brazil
cUniversidadeFederaldeMinasGerais(UFMG),HospitaldasClínicas,AmbulatóriodeRespiradorOral,BeloHorizonte,MG,Brazil dUniversidadeFederaldeMinasGerais(UFMG),FaculdadedeMedicina,HospitaldasClínicas,AmbulatóriodeRespiradorOral,
BeloHorizonte,MG,Brazil
Received15August2017;accepted27January2018 Availableonline11March2018
KEYWORDS Tomography; Mouthbreathing; Nasalcavity; Oropharynx; Nasopharynx Abstract
Introduction:Imagingstudieshavehystoricallybeenusedtosupporttheclinical
otorhinolaryn-gologicalevaluationoftheupperrespiratorytractforthediagnosisofobstructivecausesoforal breathing.
Objective: Theobjectiveofthisstudywastocompare3Dvolumetricmeasurementsofnasal
cavity,nasopharynxandoropharynxofobstructedmouth-breathingchildrenwithmeasurements ofnon-obstructedmouth-breathingchildren.
Methods:Thisretrospectivestudyincluded25mouth-breathingchildrenaged5---9years
eval-uated by otorhinolaryngological clinical examination, flexible nasoendoscopy and full-head multi-slice computed tomography. Tomographic volumetric measurements and dichotomic otorhinolaryngologicaldiagnosis (obstructedvs.non-obstructed) inthreeanatomical regions (thenasalcavity,nasopharynxandoropharynx) werecomparedandcorrelated.An indepen-dentsamplet-testwas usedtoassesstheassociationbetweenthe3Dmeasurementsofthe
夽 Please citethisarticle as:VidigalBC, Mordente CM,Cheib PL,Manzi FR,FrancoLP,Becker HM,et al.Are computed tomography 3Dmeasurementsoftheupperairwaysinmouth-breathingchildreninagreementwiththeENTclinicaldiagnosisofobstruction?BrazJ Otorhinolaryngol.2019;85:213---21.
∗Correspondingauthor.
E-mail:leticiafranco@uol.com.br(L.P.Franco). https://doi.org/10.1016/j.bjorl.2018.01.006
1808-8694/©2018Associac¸˜aoBrasileiradeOtorrinolaringologiaeCirurgiaC´ervico-Facial.PublishedbyElsevierEditoraLtda.Thisisanopen accessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).
upperairwaysandtheotorhinolaryngologicaldiagnosisofobstructioninthethreeanatomical regions.Inter-andintra-observerintraclasscorrelationcoefficientswereusedtoevaluatethe reliabilityofthe3Dmeasurements.
Results:Theintra-classcorrelationcoefficientsrangedfrom0.97to0.99.Anassociationwas
foundbetweenturbinatehypertrophyandnasalcavityvolumereduction(p<0.05)andbetween adenoidhyperplasiaandnasopharynxvolumereduction(p<0.001).Noassociationwasfound betweenpalatinetonsilhyperplasiaandoropharynxvolumereduction.
Conclusions:(1)Thenasalcavityvolumewasreducedwhenhypertrophicturbinateswere
diag-nosed;(2)thenasopharynxwasreducedwhenadenoidhyperplasiawasdiagnosed;and(3)the oropharynxvolumeofmouth-breathingchildrenwithtonsilhyperplasiawassimilartothatof non-obstructedmouth-breathingchildren.Theadoptionoftheactualanatomyofthevarious compartmentsoftheupperairwayisanimprovementtotheevaluationmethod.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
PALAVRAS-CHAVE
Tomografia; Respirac¸ãobucal; Cavidadenasal; Orofaringe; Nasofaringe
Medidasobtidasportomografiacomputadorizadaem3Ddasviasaéreassuperiores emcrianc¸ascomrespirac¸ãobucalestãodeacordocomodiagnóstico
clínico-otorrinolaringológicodeobstruc¸ão?
Resumo
Introduc¸ão:Oexameclínicootorrinolaringológicodaviaaéreasuperiortemsidohistoricamente
feitocomaajudadeimagensradiográficasparadiagnosticarcausasobstrutivasdarespirac¸ão bucal.
Objetivo:Oobjetivodesteestudofoicompararasmedidasvolumétricasem3Ddacavidade
nasal,nasofaringeeorofaringeentrecrianc¸ascomrespirac¸ãobucaleobstruc¸ãorespiratória,e crianc¸asrespiradorasbucaissemobstruc¸ãorespiratória.
Método: Estudoretrospectivoqueinclui25crianc¸asrespiradorasbucaisde5a9anosdeidade.
Ascrianc¸asforamavaliadasporexameclínicootorrinolaringológico,nasofibroscopiaflexívele tomografiacomputadorizada multi-slice.Medidasvolumétricasobtidas tomograficamentede três regiõesanatômicas (cavidade nasal,nasofaringee orofaringe) foramcorrelacionadase comparadascomdiagnóstico dicotômicootorrinolaringológico(obstruído vs.não obstruído). Umtestetdeamostraindependentefoiusadoparaavaliaraassociac¸ãoentreasmedidasem 3Ddasviasaéreassuperioreseodiagnósticootorrinolaringológicodeobstruc¸ãonastrêsregiões anatômicas.Oscoeficientesdecorrelac¸ãointraclasseintereintraobservadorforamusadospara avaliaraconfiabilidadedasmedidasem3D.
Resultados: Ocoeficientedecorrelac¸ãointraclassevarioude0,97a0,99.Umaassociac¸ãofoi
encontradaentreahipertrofiadeconchaseareduc¸ãodovolumedacavidadenasal(p<0,05) eentreahiperplasia detonsilafaríngeaeareduc¸ãodovolume danasofaringe(p<0,001). Nãofoiencontradaassociac¸ãoentreahiperplasiadatonsilapalatinaeareduc¸ãodovolumeda orofaringe.
Conclusões:1)Ovolumedacavidadenasalestavareduzidonascrianc¸ascomdiagnósticode
hipertrofiadeconchas;2)Ovolumedanasofaringeestavareduzidonascrianc¸ascomdiagnóstico dehiperplasiadetonsilafaríngea;e3)Ovolumedaorofaringedecrianc¸ascomrespirac¸ãobucal ehiperplasiadetonsilapalatinafoisemelhanteaodecrianc¸asrespiradorasbucaissemaumento datonsilapalatina.Aadoc¸ãodamensurac¸ãoanatômicadosvárioscompartimentosdaviaaérea superiorcomplementaométododeavaliac¸ão.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Publicado por Elsevier Editora Ltda. Este ´e um artigo Open Access sob uma licenc¸a CC BY (http:// creativecommons.org/licenses/by/4.0/).
Introduction
AnENTclinicalexaminationof theupperairwayhasbeen historicallyperformed withtheaidofradiographic images todiagnose obstructive causes of mouth breathing (MB).1
In recent decades, flexible nasoendoscopy has become
a diagnostic tool.2 A clinical examination combined with
flexible nasoendoscopy (FN) is the gold standard for the diagnosisofupperairwayobstruction.3,4Withtheincreasing
useofcomputedtomography(CT)inseveralhealthscience fields and the developmentof commercial software,new perspectiveshaveoccurred. Thistechnology, amongother
features,enablesfasterandmorereliablemeasurementof airwayvolumeandarea.5---9CTimagesarereproducible,do
nothavemagnificationerror,andallow3Dmeasurements. Volumetricairwaymeasurementshavebeenusedinseveral studies and have been proposed as the gold standard scientific method for the study of breathing problems.10
However, validation of using 3D reconstructions for the diagnosisofobstructivetissueshasnotbeenpresented.
Severalobstructivefactorsareinvolvedintheetiologyof respiratory sleep disorders.5,11,12 Hypertrophic turbinates,
adenoids and tonsils have an important effect, playing a major role in the etiology of respiratory obstruction of young patients.6,13,14 Early diagnosis of upper airway
obstruction might contribute to a timely referral to ENT physicians, preventing complications and improving the qualityoflifeofpatients.AgreementbetweenreducedCT volume measurements of the upper airways and an ENT diagnosis of obstruction couldbenefit scientific investiga-tions, and eventually the clinical practice. Studies have shownthatCTairwayvolumemeasurements,despitebeing highly reproducible within the same software, have low agreementwhendifferentprogramsandmethodologiesare used.6,8,13 A great variability in measurement values is
foundbecausethereferencestructuresusedforCTairway measurements2---4,8,9,11,13,15 havebeen basedonthecriteria
ofindividualresearchers.Theboundariesofthecavitiesthat comprisetheupperairwayshavenotbeenbasedon anatom-icallandmarks; typically, theyarebasedon thelines and planesthatfacilitateconvenientreproducibility.
Thepurposeofthisretrospectivestudywastoinvestigate whether3D volumetricmeasurements ofthe nasalcavity, nasopharynxandoropharynxofobstructedMBchildrenare different from the measurements of MB children without theupperairwayobstructionwhenpreciseanatomical land-marksboundariesareemployed.
Methods
Sample
TheInstitutionalReviewBoard(ComitêdeÉticaemPesquisa da Pontifícia Universidade Católica de Minas Gerais) approved theuse of the hospitaldatabase. Patients’ par-entshadsignedaninformedconsentauthorizingtheuseof examsforscientificpurposes.Theprivacyofallsubjectswas protected.
Fromapopulationof1234childrenscreenedandtreated by team of otolaryngologists, allergists, speech pathol-ogists, physical therapists and orthodontists, between November,2002 andSeptember,2014,at theHospital das ClínicasdaUniversidadeFederaldeMinasGerais,hospital, 28individualswhohadbeen submittedtomulti-slice com-putedtomography(MSCT)scans,inadditiontoconventional ENTclinical andendoscopicexaminations,were selected. All these children were diagnosed as obstructive sleep apnea(OSA)patientsbypolissonographyandreferredtoa MSCTstudytobetterclarifythelevelsoftheupperairway obstruction. MSCT obtained for patients with syndromes, nasal septum deviation, craniofacial malformations and previousENTsurgicalprocedureswerenotincluded inthe sample.Afterexcludingthreesubjects,becauseofthepoor
qualityoftheirexams,notadequateforresearchpurposes, thetotalconveniencesamplewascomposedof25children (13 girls and 12 boys), 5---9 years old (mean=6.56 years, median=6years).
Theanatomicalairwaylandmarksproposedinthis inves-tigation have not been used in previous publications. Therefore, the sample size was calculated based on the standard deviation of the analysis of the first consecu-tive 10 cases. At least 12 patients should be included in eachENT-diagnosisgroup(obstructedvs. non-obstructed). Obstructionshouldbelocatedinatleastoneof thethree anatomical sites (nasal cavity, nasopharynx and orophar-ynx),basedonanalphasignificancelevelof0.05andabeta levelof 0.2 toachieve a power of 80% todetect a mean differenceof10%betweenthegroups.
ENTassessment
BasedontheclinicalandendoscopicENTexaminations per-formed by two of the authors at the first consultation, the obstruction of upper airway obstruction could either be related to the nasal cavity, nasopharynx or orophar-ynx (Fig. 1). The endoscopic examination was performed byan experienced otolaryngologist, using a flexible naso-laryngoscope,3.2mm(MachidaENT-30PIII),associatedwith anendocoupler.Topicalsprayanesthesia(2%lidocainewith epinephrineataconcentrationof1:20,000)waspreviously administeredtoreducediscomfort.
The nasal cavity was considered obstructed when the inferiorand/ormiddleturbinateswerehypertrophic accord-ingtotheanteriorrhinoscopyandtheobstructionpersisted afternasal decongestionwith atopical vasoconstrictor.It wasconsiderednasopharyngealobstructionwhenadenoidal hyperplasiawaspresent, occupying morethan 75%of the choanalregion.16,17 Oropharynx obstructionwasdiagnosed
onthebasisofBrodskyandKochGrade3or4palatinetonsil hyperplasia.18
Based on the ENT clinical diagnosis, children were groupedaccordingtothefindingsof thethreeanatomical regions of the upper airways. The nasal cavity and naso-pharynxgroups werecomposedof 13obstructivesubjects and12non-obstructivesubjectseach.Theoropharynxgroup included12obstructivesubjectsand13non-obstructive sub-jects.Obstructedandnon-obstructedchildrenweresexand agematched.
Volumetricmeasurementoftheupperairways
Nineteenchildren hadaMSCTimageof theairwaystaken onthedayoftheENTclinicalexamination,whiletheother six children were submitted to CT scan within the first weekofENTclinicalexamination.TheMSCTswereacquired onthesame equipment(Somatommultislicescanner, 128 units,Siemens,Erlangen,Germany)with100kVanda36mA current timeof 1.57s tube voltage acquisition. The radi-ologist responsible for the selected patients’ exams was trained,calibratedandwasblindedtotheresultsofclinical andendoscopicexaminationsperformed by otorhinolaryn-gologists.Thechildrenhadbeeninstructednottobreathe deeply, not to swallow, and not to move their head and tongueduringthescanning,andtheywerepositionedina
Figure1 Airwaysmeasurement.A,nasalcavity;B,nasopharynx;C,oropharynx.
Figure2 MSCTpatient’sorientation.A,sagittalview;B,coronalview;C,axialview.
supineposition. The collimation was1mm, and the slice thicknesswas0.6mm.
To standardize the measurements and minimize the errors,the3DconstructedMSCTimagewasreorientedinthe threespatialplanes.Inthefrontalview(thecoronalplane), theheadwaspositionedwiththelineconnectingtheright andleftfronto-zygomaticsuturesparalleltothefloor.Inthe rightlateralview(thesagittalplane),theFrankfurt Horizon-tal(FH)planewasusedasthereferenceplane,whichwas positionedparallel to the floor. FH wasconstructed from therightporion,locatedinthemostlaterosuperiorpointof theexternal auditorymeatus,andthe right orbitale.The
superiorview(theaxialplane)wasconstructedthroughthe cristagalliandbasion,andthelineconnectingthe anatom-icalstructurewasalignedparalleltothemid-sagittalplane andperpendiculartotheground(Fig.2).
The volumetric construction and measurements were performedbyanexperiencedradiologistwithpreviously cal-ibrated specific tools to calculate the volume of airways (Figs. 3---5) (3D-mode airway/sinus Dolphin Imaging soft-ware, version 11.5, Chatsworth, CA, USA). The threshold valuewassetat73,9 andtheanatomicalboundarieswere
established usingthecranialtechnicalpointsdescribed in
Figure3 NasalcavityvolumetricMSCTmeasurement.A,coronalview,pyriformapertureboundaries.B,axialview,lateralwalls ofnasalcavity.C,sagittalview,anatomiclandmarksdescribedinTable1.D,sagittalviewofthenasalcavityvolume.
Figure4 Nasopharynxvolumetricmeasurement.A,sagittalview,anatomiclandmarksdescribedinTable2.B,sagittalviewof thenasopharynxvolume.
Figure5 Oropharynxvolumetricmeasurement.A,sagittalview,anatomiclandmarksdescribedinTable3.B,asagittalviewof theoropharynxvolume.
Table1 Craniallandmarksusedinthenasalcavityanatomicboundariesconstruction.
Craniallandmarks Definition
Anteriornasalspine Mostanteriorpointofthefloorofthenasalfossa,atthebottomofthenostril. Posteriornasalspine Mostposteriorpointofthepalatineboneandthefloorofthenasalcavities. Nasion Pointlocatedinthecenterofthefrontonasalsuture
Nasalbone Thelowestpointofnasalbone
Pterygomaxillaryfissure Lowestpointofthepterygomaxillaryfissure
Atlas MostanteriorinferiorpointoftheAtlasvertebra
Vomer Pointlocatedintheposteriorportionofthevomerbone
Nostril Anteriorportionofthenostrilopening
Nose Anteriorportionofthenosetip
Table2 Craniallandmarksusedinthenasopharynxanatomicboundariesconstruction. Craniallandmarks Definition
Posteriornasalspine Mostposteriorpointofthepalatineboneandthefloorofthenasalcavities Vomer Pointlocatedintheposteriorportionofthevomerbone
Basion Pointlocatedintheinferiorandposteriorlimitoftheanteriorborderoftheforamenmagnum Pterygomaxillaryfissure Lowestpointofthepterygomaxillaryfossa
Atlas Anteriorinferiorpointofatlasvertebra
Table3 Craniallandmarksusedintheoropharynxanatomicboundariesconstruction.
Craniallandmarks Definition
Posteriornasalspine Mostposteriorpointofthepalatineboneandthefloorofthenasalcavities.
Atlas Anteriorinferiorpointofatlasvertebra
Hyoid Posteriorinferiorpointofthehyoidbone
C3vertebra Superior-anteriorpointoftheC3vertebra
Statisticalmethods
To determine errors in the landmark identification and
measurements, 20 subjects were randomly selected, and
a second investigator remeasured the identical scans.
The firstinvestigator remeasuredfourteen subjects,after
an interval of one month. The intraclass correlation
coefficients (ICC) was calculated to assess the
interex-aminer andintraexamineragreement. Fortheassessment
of the differences between the obstructed and
non-obstructed children, we used an independent sample
t-test. The assumptions of normality within each group (Kolmogorov---Smirnovtest) andhomoscedasticity(Levene)
18000
14000 12000 10000
Obstructive Non-obstructive Obstructive Obstructive
P-value = 0.014 P-value = 0.018 P-value = 0.497
Turbinates Adenoids Tonsils
Non-obstructive Non-obstructive 8000 5000 6000 8000 10000 4000 4000 3000 2000 2000 1000 0 0 Nasal ca vity MSCT v o lume measurement Nasophar inx MSCT v o
lume measurement Orophar
inx
MSCT v
o
lume measurement
16000
Figure6 MSCT3DvolumetricmeasurementofA,nasalcavity;B,oropharynx;andC,oropharynxinobstructedandnon-obstructed subjectsaccordingtoENTclinicalandnasoendoscopydiagnosis.
Thesignificancelevelwassetatp<0.05.Thedatawere analyzedusingSPSS, version20.0(SPSS,Inc.,Chicago,IL, USA).
Results
The ICC was 0.99 for the interobserver nasal cavity and
oropharynxevaluationand0.97fortheinterobserver naso-pharynxevaluation.TheICCwas0.98fortheintraobserver nasal cavity evaluationand 0.98 for the nasopharynx and oropharynxintraobserverevaluation.Reproducibilityofthe methodwasconsiderednearlyperfect.
Fig.6showhistogramswiththecomparisonbetweenthe MB subjects with ENT diagnoses of obstructive and non-obstructive airways in the three anatomical sites (nasal cavity,nasopharynxandoropharynx).
The MSCT-3D nasalcavity measurementsshoweda30% volumereduction(p<0.05)intheMBchildrenwith obstruc-tiveturbinates,incomparisonwiththeMBchildrenwhose turbinateswereconsideredwithinnormallimits(10,564vs. 15,073mm3). Additionally, the nasopharynx volume
mea-surementwasassociatedwithlymphatictissuehyperplasia. Thechildrenwhoseadenoidswhereconsideredobstructive accordingtotheENTexaminationpresentedastatistically significantreducednasopharynxvolume(2757vs.4143mm3)
incomparisonwiththenon-obstructiveadenoidMBchildren (p<0.05),whichrepresentsa33%airwayvolumereduction. The MSCT measurementsof the oropharynx volume were not associated with obstructive tonsils. The MB children with obstructive tonsils showed an oropharynx measure-mentof6094mm3,whereasthechildrenwithoutobstructive
tonsilsshoweda5453mm3measurement.The11.5%
reduc-tion of the oropharynxairway volumeof the MB children without obstructivetonsilswasnotstatisticallysignificant (p=0.497).
Discussion
Excellent intra- and interobserver agreement (ICC 0.97---0.99) was found in this investigation. This high reproducibilityhasalsobeen describedinpreviousstudies with volumetric measurements of upper airways.5,6,9,14
However, the validityof the volumetric3D-CT scan mea-surementsoftheupperairwaysmeritsconcernandshould bebetter assessed.6,19 The objectiveof this study wasto
evaluatewhetherthe3Dmeasurementsofthenasalcavity,
nasopharynxandoropharynxareinagreementwiththeENT goldstandardclinicaldiagnosis.Toincreasethevalidityof themeasurements,weselectedtheanatomicallandmarks, rather than the reference lines and planes, used in the previous studies, which did not accurately portray the boundariesofeachregionoftheupperairways.8,11,15,20We
hypothesizethattheadoptionoftheactualanatomyofthe compartmentsoftheupperairspaceis animprovementin themeasurementmethod.
Itwasfoundthatthereductionofthevolumeofthenasal cavityandnasopharynxareassociatedwithhypertrophied turbinatesandenlargedadenoids,respectively. But,when thetonsilswereenlarged,noagreementwasobservedinthe reductionof the 3D oropharynxvolume. The 3D orophar-ynxvolumetric measurement of tonsils’obstructed group andtonsils’non-obstructedgroup wasstatisticallysimilar. Thisresultwasunexpectedbecauseitappearscontradictory thattheoropharynxcouldbeatleastpartiallyoccupiedby enlargedlymphoidtissueanditsvolumeremainsunchanged. Thisfindingmightbeattributedtomoreposterior position-ingofthetongueduringtheexaminationofthepatientin asupinepositionduringtheMSCTscan.4,17,21Thisposterior
dropofthetonguewithintheoropharynx,whichappeared inallofthesubjects,mighthavemaskedtheactualvolume of that anatomical site in the MB children without tonsil enlargement.Therefore, a false-positive reductionof the airways might be seen in CT scans of patients in supine position.Ourfindingsinregardtheoropharynxmustbe dif-ferentthanformerstudiesthatusedconebeamcomputed tomography(CBCT)inseatedposition.However,we under-standthatwhenchildrenareinasupineposition,theyare placedin a condition closerto thesleeping positionthan if they were seated, which is used by most CBCT equip-ment.AnotheradvantageofMSCT,incomparisonwithCBCT, istheacquisitiontime.MSCTissignificantlyfaster(1.57s), incontrastwiththatofCBCT(40s),facilitatingthe examina-tionofnon-compliantyoungchildrenandreducingthebias of respiratory movements that occurs in time-consuming examinations.21,22
Several methodologies have been proposed for airway evaluationonlateralradiographs1,2,10andCTimages.6,8,14,23
A revision of the previously published data on this topic showsthattheanatomicaldefinitionoftheairwayshasbeen extremely variable and not based on precise anatomical landmarks.8,10,13 In thisstudy we usedtheactual
anatom-icallandmarks, asdefinedin Tables 1---3.Instead ofusing theanteriornasal spine astheanteriorlimit of thenasal
cavity,6,15,24 we considered the full nose extension tothe
nostrilopeningforthevolumetricmeasurements. Addition-ally,the upperlimit of the nasalcavity wasimproved. In a previous study, the height of the nasal cavity was sig-nificantlyunder measured. To improvethe validityof the nasopharynxmeasurements,thechoanawasconsideredthe anteriorwall.Previousstudiesdidnotevaluatethe nasopha-rynxadequatelybecause,inmostcases,asignificantportion ofthenasalcavitywasincludedinthenasopharynx.6,10,20
This is a pioneer study in the assessment of changes in the 3D volume of specific sites of the upper airways. Our measurement method and findings can contribute in futurescientific investigations of 3D assessment of upper airwaysbecauseit isbasedonactual anatomiclandmarks andnotconvenientlandmarks,whichdidnotrepresentthe realanatomic region. The evidence in the present inves-tigationconfirmedthatthe volumetricassessmentsofthe upperairways by MSCTarequite reproducible. Weadded informationshowingthat itis likelythat turbinate hyper-trophyandadenoidhyperplasiawouldbefoundinthecases in which the nasal cavity and nasopharynx volumes are reduced.ThevolumeoftheoropharynxfromtheMSCT mea-surementsisnotassociatedwithobstructionbythepalatine tonsils.Additionalresearchisneededtoelucidatethe asso-ciation between palatine tonsil obstruction and its effect ontheairwaysinMBchildreninseatedandaswellsupine position.
As a final statement, it is important to note that the indicationofMSCTisnotroutineintheevaluationof mouth-breathingchildrenandshouldbereservedforexceptional, butnotsorare,cases.
Conclusions
BasedonthevolumetricMSCTfindingsandtheENT diagno-sis,thefollowingconclusionscouldbeinferred:
1) The nasalcavityvolumewasreducedinthepatientsin whichhypertrophicturbinateswerediagnosed.
2) The nasopharynx wasreducedinthe patientsin which hyperplasiaadenoidswerediagnosed.
3) Theoropharynxvolumeofmouthbreathingchildrenwith obstructedtonsilswassimilartothatofnon-obstructed mouthbreathingchildren.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
Acknowledgments
WethankMrs.PaulaCheibVilefortforherkindcontribution intheartwork.
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