HRCT IN PEDIATRIC DIFFUSE LUNG DISEASE

Sanjay P Prabhu, MBBS, FRCR

Staff Pediatric Radiologist Boston Children’s Hospital Department of Radiology

Assistant Professor of Radiology Harvard Medical School

Boston, MA

OBJECTIVES•  HowIdealwithaHRCTrequestinachild?•  Technicalchallenges-ge?ngbeAerimages•  Howtoformulateausefulreport•  Terminology•  LatestclassificaHonofILDinchildren&infants

HRCT•  CheckChestradiograph(s)andpriorCTs•  Lowdosetechnique•  SamplingdiffuseorwidespreadabnormaliHes•  Concentratesonpulmonaryparenchyma•  DoesNOTevaluatelargeairwaysormediasHnum•  DoesNOThelpifconvenHonalCTisnormal•  Mostcases-thinsecHonsfrommulHslicelowdoseacquisiHonsuffice

Mo#onAr#factonHigh-Resolu#onCTImagesofPediatricPa#ents:ComparisonofVolumetricandAxialCTMethods-BastosM,LeeEYetal–AJRNovember2009,Vol193,Number5

Technicalaspects

•  Weight/size/age-baseddosing•  80-120kVp•  1mmslices•  7mmto20mmintervals•  FastacquisiHon•  6-8slicesininspiraHon•  Minimumof4expiratoryslices

Dose

•  CompareCTscannersforrelaHvedose•  Usebreastshields•  Scanlimitedareaifpossible•  Increasedsharpness(butincreasednoise)

PreparethepaHent•  PaHentcooperaHonorcontroliskey•  InspiraHonin4to6yearolds•  ExpiraHon6to8yearolds•  Child-friendlyscanner•  Technologist/Radiologist/playtherapistinroomtocoachunHl10-12yearsold

PaHentPreparaHon

•  Explainbeforeenteringtheroom•  RepeatandpracHceagainonthetable•  SpeaktopaHentduringtheprocedure•  Helpstohaveparentinroomduringscan

Youngerchildren

•  QuietbreathingisnotadequateforHRCT•  MoHondegradesimages•  Considerdecubitusimaging•  ControlledvenHlaHonCT•  IntubaHoncannotbeavoidedintheyoungchild

Decubitusimaging•  PerforminiHalHRCT•  LateraldecubitusposiHon

•  Upsideisinspiratory•  Downsideisexpiratory

LucayaetalAJR2000174:235-41

ControlledvenHlaHonCT

•  VenHlaHonwithfacemask•  CO2andcheststretchreceptorsproduce10-15secondsofapnea

•  InspiraHonandexpiraHonimagesduringapneicperiod

Generalanesthesia

•  Mainchallengeisatelectasis

•  ScanassoonaspossibleaherintubaHon

•  MaintainrelaHvelyhighinspiratorypressure(30cmwater)withfrequentsighs

•  Pronescanninghelpsreducetheatelectasis

FormulaHngthereport² Startwithlarge&small

airways² Defineparenchymal

abnormality² Groundglass/nodules/

cysts/Emphysema/Linear/reHcular

² TerminologysimilartoadultHRCT(useGlossary*)

² Diagnosesdifferent

HansellDMetalFleischnerSociety:glossaryoftermsforthoracicimaging.Radiology.2008;246:697–722.

Treeinbud•  Inspissatedmaterialindistalbronchioles

•  MAIandotherinfecHons

•  ChronicaspiraHon

GroundglassaAenuaHon•  Hazyincreased

aAenuaHonoflungwithpreservedvisibilityofbronchovascularstructures

•  Verynon-specific•  Increasedcapillaryblood

volume(shunHng)OR•  IntersHHalthickeningOR•  Alveolarfillingwithcells,

fluidsorothermaterial

Niemann-PicktypeCdisease

MosaicaAenuaHon•  AAributabletopatchy

intersHHaldiseaseorsmallairwaydiseasewithairtrapping

•  BUTcanalsobeseenwithpulmonaryhypertension,thromboembolism,orotherocclusivevasculardiseasethatresultsinmixedoligemicandplethoriclung.

MosaicaAenuaHon

Airtrappingpresent Airtrappinginfrequent

Smallairwaysdisease Parenchymaldisease Pulmonaryvasculardisease

DiagnosesandclassificaHon

•  AdultclassificaHonDOESNOTworkinchildhoodILDordiffuselungdisease

•  Childhooddiagnosesaredifferent•  ChILDcharacterizedby-

– CombinaHonofhyperinflaHon,mosaicaAenuaHon,airtrapping,ground-glassopaciHes,consolidaHon,linear/reHcularopaciHes,nodules,orcysts

ClinicopathologicclassificaHonofchildhoodILD

I.  DisordersofInfancyII.  DisordersofthenormalhostIII.  DisordersrelatedtosystemicdiseasesIV.  DisordersoftheimmunocompromisedhostV.  DisordersmasqueradingasILD

DISORDERSOFINFANCY

Disordersofinfancy-1•  Diffusedevelopmentaldisorders

–  Acinardysplasia–  Congenitalalveolardysplasia(CAD)–  Alveolarcapillarydysplasiawithmisalignedpulmonaryveins(ACDMPV)

•  Terminfants,rapidandprogressivelyworseninghypoxiaohenwithseverePHTaherbirthorearlyneonatalperiod

•  Earlydeath,soHRCTfindingsarenotreadilyavailable•  Radiographs-NormaltodecreasedlungvolumeswithdiffuseopaciHesresemblinghyalinemembranedisease

Disordersofinfancy-2•  Growthdisorders

–  PulmonaryhypoplasiaassocwithcondiHonslikeoligohydramniosorneuromusculardisease

–  PrematurityassociatedBPD–  StructuralabnassociatedwithcondiHonslikeTrisomy21andDownsyndrome

•  43%diffuselungdiseaseininfants

•  LookforunderlyingcondiHons

Growthdisorders-Imagingfeatures

•  SmallperipheralcystsasinTrisomy21orTurnersyndrome

Disordersofinfancy-3

•  SurfactantdysfuncMondisorders– SurfactantproteinB&C,ATP-bindingcasseAetransporterproteinA3(ABCA3)deficiencies

– RarerdisordersTTF1andlysinuricproteinintolerance

– Respiratoryfailureatbirth(SpB&ABCA3)orlaterpostnatallywithpersistenttachypneaandhypoxemia(SpC&ABCA3)

– Familyhistoryoflungdisease

SurfactantdysfuncHon–imagingfeatures

•  DiffusehazyorgranularparenchymalopaciHes(groundglassopaciHes)onCXR

•  GGO&variableinterlobularseptalthickeningonHRCT

3months 5months

Disordersofinfancy-4

SpecificcondiMonsofundefinedeMology•  NEHI-neuroendocrinehyperplasiaofinfancy•  PIG-pulmonaryintersHHalglycogenosis

•  NEHI-PersistenttachypneaofinfancyorfollicularbronchiHs-Terminfants-iniHallywellandthenpersistenttachypnea,retracHons,hypoxemiaandcrackleswithoutcoughorwheezingby3monthsage

•  PIG-Preterm&terminfantswithtachypneasoonaherbirth

Imagingfeatures•  NEHI

–  hyperinflaHon,perihilaropaciHesonCXR

–  GGOwithcentralpredominanceinlingulaandRML

–  MarkedhyperinflaHononexpiraHon

–  HRCTis78%sensiMveand100%specificforNEHI

–  CentralandanteriordistribuMon

–  Path:rouMnestainingmaybenon-specificorshowminorchange

–  Bombesinstainingrequired

PIG•  PulmonaryintersHHal

glycogenesis•  BilateralhyperinflaHon•  DiffuseintersHHal

markingsonCXR•  GGO•  Interlobularseptal

thickeninginmainlysubpleuraldistribuHon

•  Air-filledcystshavebeenalsodescribed

Disordersofthenormalhost•  AcuteinfecHon•  PostinfecHousairwayinjury

•  Non-infecHousdisorders•  AspiraHonsyndromes•  Eosinophilicpneumonias•  AcuteIntersHHalpneumonia

•  Idiopathicpulmonaryhemosiderosis

Chroniceosinophilicpneumonia

DISORDERSOFSYSTEMICDISEASEPROCESSES

Immunerelateddisorders

•  Acquiredpulmonaryalveolarproteinosis

•  Immunemediatedpulmonaryhemorrhagesyndromes

•  Nonhemorrhagicparenchymaldisease(collagenvasculardisease)

•  Wegener’sgranulomatosis

Pulmonaryhemorrhagein4year-oldwithanemiaand

hemoptysis

Nonimmunerelateddisorders

•  Sarcoidosis•  LangerhanscellhisHocytosis

•  CysHcfibrosis•  Marfanassociatedpulmonarydisorders

•  Malignantinfiltrates

CysHcfibrosis

LCHlung

IV.DISORDERSINTHEIMMUNOCOMPROMISEDHOST

OpportunisHcinfecHons

CMVinfecHoninpostBMTpaHent

CandidainfecHoninpostBMTpaHent

Congenitalimmunodeficiency

•  ChronicGranulomatousDisease

•  Commonvariableimmunodeficiency(CVID)

Acquiredimmunodeficiency•  Non-infecHous

chemotherapeuHcdrugrelatedlunginjury

•  RadiaHonrelatedlungdisease

•  LookforintersHHalprominenceandalveolaropaciHes

•  Eventuallyfibrosisresults

Disordersrelatedtolung,BMT&solidorgantransplantaHon

•  RejecHon•  GVHD•  PTLD

ObilteraHvebronchioliHsduetograhversushostdisease

V.DISORDERSMASQUERADINGASILD

DisordersmasqueradingasILD

•  Arterialhypertensivevasculopathy•  CongesHvevasculopathy•  LymphaHcdisorders•  Pulmonaryalveolarproteinosis•  Pulmonaryedema

LymphaHcdisorders

InfantwithlargecervicothoracicLM

•  DiffuseperibronchovascularintersHHalthickening

•  Interlobularseptalthickening

•  Chylouspleuraleffusioncommon

Pulmonaryedema•  Imagingfeaturesfollows

stagesofincreasingseverity

•  Groundglassopacity•  Smoothintralobular

septalthickening•  Fissuralthickening•  Pleuraleffusions•  Lookforalehatrial&

ventricularenlargementincardiogenicedema

Pulmonaryalveolarproteinosis

•  Pulmonaryalveolarproteinosis

•  “Crazy-paving”•  Specificresponsetoaninsult,butnoteMology

•  Lookforsurfactantproteindeficiency,inhalaHonexposure,lipoidaspiraHonandimmunecompromise

Summary

•  TechniqueofHRCT•  Roleofexpiratory,proneanddecubitusimaging

•  Terminology•  UpdatedclassificaHonofchildhoodILDwithexamples

•  Clinical-radiologicalcorrelaHon