Obstetric Ultrasound - CMRI

209 Pages·2008·10.67 MB·English

BLUK104-Hobbins August29,2007 19:0
Obstetric Ultrasound
i
BLUK104-Hobbins August29,2007 19:0
Obstetric
Ultrasound:
Artistry in Practice
John C. Hobbins, MD
ProfessorofObstetricsandGynecology
UniversityofColoradoHealthSciencesCenter
Denver,Colorado
iii
BLUK104-Hobbins August29,2007 19:0
(cid:2)C2008JohnC.Hobbins
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Firstpublished2008
1 2008
LibraryofCongressCataloging-in-PublicationData
Hobbins,JohnC.,1936-
Obstetricultrasound:artistryinpractice/JohnC.Hobbins.
p.;cm.
Includesbibliographicalreferencesandindex.
ISBN978-1-4051-5815-2
1.Ultrasonicsinobstetrics. I.Title.
[DNLM:1.Ultrasonography,Prenatal–methods. 2.EmbryonicDevelopment.
3.FetalDevelopment. 4.FetalDiseases–ultrasonography. 5.Pregnancy–physiology.
6.PregnancyComplications–ultrasonography.WQ209H682o2007]
RG527.5.U48H592007
618.2(cid:3)07543–dc22
2007008365
ISBN:978-1-4051-5815-2
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BLUK104-Hobbins August29,2007 19:0
Contents
Foreword,viii
Preface,ix
1 Earlypregnancyloss,1
2 Placentaandumbilicalcord,7
3 Assessmentofamnioticfluid,20
4 Fetalbiometry,30
5 Intrauterinegrowthrestriction,35
6 Examinationofthefetalcranium,44
7 Examinationofthefetalheart,61
8 Fetalspine,76
9 Fetalabdomen,82
10 Fetalkidneys,88
11 Fetallimbs,91
12 Multiplegestations,99
13 Advancedmaternalage,107
14 Diabetes,122
15 Preeclampsia,127
16 Pretermlabor,132
17 Rhdisease(erythroblastosisfetalis),145
18 3Dand4Dultrasound,149
19 Thesafetyofultrasound,155
20 Thebiophysicalprofile(BPP),158
21 Ultrasoundonthelaboranddeliveryfloor,161
22 TheHobbinstakeonvarioushottopics,166
Appendix,171
Index,191
Colorplatesectionisfoundfacingp.22
v
BLUK104-Hobbins August29,2007 19:0
Dedication
Ihavededicatedthisbooktothreepeople. Elaine, this book was written for you and others like
Mydadwastheidealrolemodel.Hepossessedincredi- youwhosefetuseshaveproblemsthatmightbehelpedby
bletalent,intelligence,integrity,andhumility.Ithasbeen somemessagescontainedwithin.
toughtotrytomatchuptosomeonewhowasthetotal Last,Iamdedicatingthisbooktomywife,Susan.She
package(althoughIwillbetheneverrealizedit).Thede- hasprovidedmuchoftheinspirationforit.
scription“hespeakssoftlybutcarriesabigstick”fithim Afterspendingthefirstpartofmycareerseekingnew—
perfectly,excepthedidn’tneedabigsticksinceItoedthe and often invasive—ways to find out more about the
line(mostofthetime)simplybecauseIdidnotwishto fetuses, my energies then turned toward finding non-
displeasehim. invasivesubstitutes.Whileinthatmindset,Susan,anurse
Theword“artistry”inthebooktitleisnottherebyacci- midwife,helpedmetofurtherunderstandthatinmany
dent.Mydad,mybrother,andoneofmysonswere/arefine wayswe,asproviders,haveatendencytointerfereinwhat
artistsbytrade,butmyveryrudimentarytalenthasbeen isgenerallyaverynaturalandnormalprocess.Our“ready,
limitedtodrawingstickfigurefetusesduringcounseling shoot,aim”thinkingevolvedtohelppatients,butoftenit
sessions. However, everyone in ultrasound is displaying canhavetheoppositeeffect.Shehasstimulatedmetotry
aformofartistry—artistryinobtainingtheinformation toputthe“aim”backinitsproperplaceinthediagnostic
andartistryinputtingtheinformationintoplay. sequence.
Thankyou,dad,forguidingmeeveryday. Susan,Ideeplyappreciateyoursupportand,recently,
Elaineisoneofthemostremarkableofthethousands yourpatiencewithmewhileIspenthoursandhourssit-
ofpatientsIhavehadthepleasureofmeetingoverthepast tinginfrontofthecomputer(yours)—oftenswearingat
40years.Sheparticipatedfullyinherowncare,andeven myineptattemptstocompletethesimplesttasks—when
providedmewithsnippetsfromtheliteraturewhenIwas wecouldbeplayingtennisordoingsomethinginfinitely
struggling with her diagnosis. Her remarkable courage, moreentertaining.
determination,andimpressiveintellectenergizedme. Thankyouforaddingsomuchtomylife.
Acknowledgments
Foranacademicdepartmenttobesuccessful,itmusthave ofourhundredsofdiscussionsaboutultrasound,sports,
anexcellentcoordinator.ThroughtheyearsIhavebeen andpolitics.Hehasbeenresponsibleformanyoftheim-
luckytohavehadonlyfiveperinatalcoordinators––allof ages in this book, which obviously are essential to the
them world-class. Jane Berg, who, as well as possessing messageswithinit.
amyriadoforganizationaltalents,alsohastheabilityto Thankyouforeverything,Wayne.
tweakeverythingpossibleoutofthecomputer.Inaddi- Helen MacFarlane provided most of the illustrations
tion,shereadsatleastasmuchoftheperinatalliteratureas forthisbook.Sincethiswasdesignedtobea“nuts-and-
ourfellows,andhasa“Jeopardy-like”abilitytoremember bolts”typeoftext,wedecidedtomaketheillustrations
evenobscurepapers. reflectthisconcept.Ratherthan“Netter-like”renditions,
Iknowthisprojecthasnotonlytestedheraboveskills, weresortedtothesimplestofdiagrams,andHelendida
but,attimes,herpatience,andIamdeeplyindebted. remarkablejoboffollowingthatpathway.
Thankyou,Jane.Itwouldhavebeenverydifficultto Thankyousomuch,Helen.
pullthisoffwithoutyou. A large “thank you” goes to John Queenan, who has
WaynePersutteandIhaveworkedtogetherformore providedtheforwardtothisbook.Whobettertowritethis
than15years,andIhavethoroughlyenjoyedeveryminute thanoneofthemostrespectedindividualsinOB/GYN?
vi
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Dedication vii
ManyyearsagoIwasaninterninacommunityhospital teacher,andleaderinthetherapyofRhdisease,Idecided
inConnecticutandJohnwasonthestaffthere,aswellas Iwantedtobehim.John,youareoneofthe4individuals
beingafacultymemberatCornellMedicalSchoolinNew whoinfluencedmetodowhatIdo,includingwritingthis
York City. After watching him in action as a clinician, book.
BLUK104-Hobbins August29,2007 19:0
Foreword
A medical pundit was once asked, “What are the three evidence-based scientific manuscripts. While advancing
greatestadvancesinobstetricsandgynecologyofthelast medicalknowledge,thereisalossofauthor’sexperience
decade?”Hisanswerwasswiftanddefinitive:“Ultrasound, andadviceinsuchmanuscripts.EnterJohnC.Hobbins,
ultrasound,ultrasound.”Whileallofuscouldaddtothe MD,oneoftheoutstandingteachersandresearchersfrom
list,thereislittledoubtoftheprimacyofsonographyin theonsetofclinicalsonography,threedecadesago.From
clinicalmedicine.Thismodalityhasmadeaprofoundim- thestart,Dr.Hobbins’skillsatscanningwereartistryin
provementinthedeliveryofcareinnumerousways:de- practice.Tome,readingthisbookislikefollowingPablo
tectingcongenitalanomalies,earlyfetallife,andectopic Picasso, Dr. Hobbin’s favorite artist, on a personal tour
pregnancies;establishinggestationalage;andevaluating of his gallery. How refreshing to read the thoughts and
fetal condition in Rh disease, multiple gestations or in- adviceofaworld-classexpert.Inundertakingthisproject
trauterinegrowthrestriction. Dr.Hobbinshascraftedthebooktoservebothpatients
Dr.Hobbinsbeginsthisbookbypresentingasystematic andthemedicalprofession.Ibelieveitfullyachieveshis
reviewofthefetalphysicalexam.Inchapter12hestartsto mission.
definetheroleofsonographyinmanyclinicalproblems
andendswithpracticalusesofthistechnologyinachang- JohnT.Queenan,MD
ingworld.HecloseswithvintageHobbins,expounding ProfessorofObstetricsandGynecology
onvarioushottopics.Theappendixcontainshisselection andChairEmeritus
ofusefulclinicaltables. GeorgetownUniversityMedicalCenter
Over the last half decade as the deputy editor of DeputyEditor,ObstetricsandGynecology
Obstetrics and Gynecology I have been immersed in August2007
viii
BLUK104-Hobbins August29,2007 19:0
Preface
Duringthe35yearsthatIhavebeenimmersedintheprac- features to substantially improve the images, some key-
ticeofperinatalmedicine,ithasbeenpossibletochronicle boardsnowlookliketheinstrumentpanelsofajumbojet.
intimatelytheevolvingroleofultrasound.Atfirst,itwas Also,althoughcompaniesareconstantlystrivingtomake
usedtoanswerafewbasicquestionsregardinggestational theirkeyboardthemostuser-friendlyfeatureeverfash-
age,fetalandplacentalposition,andtoruleoutmultiple ioned,nokeyboardisthesame—somethingthatisvery
gestations.Nowthemodalitycanunrooftheinnermost frustratingtoadyslexicmultiplemachine-userlikeme.
secretsofthefetusthroughtwo-dimensionalandthree- What is the point of this stroll down memory lane
dimensionalimageryandDopplerwaveformanalysis. (whichgenerallyproducesthesamegagreflexastelling
In1977,oneofthefirstbooksdedicatedtoultrasound ayoungresidentthatweusedtoworkeveryothernight)?
waswrittenbyFredWinsbergandme.Thesecondedi- It is to point out that, while all this was going on, ul-
tionwascoauthoredwithRichardBerkowitz,oneofthe trasoundhasevolvedfromsomethingthatwouldanswer
greatthinkersinthefield.Bothtimes,wehaddifficulty afewclinicalquestionstoanowindispensabletoolthat
infillingupthesethinbookswithenoughinformationto playsamajorroleineverypregnancy.Justlikethehistory
makethemworthselling.Atthattime,mostpractitioners ofultrasoundtechnology,whichhastakenmanytangents,
wereusinga“contactscanner”thatrequiredtheoperator theclinicalpathwayofultrasoundhasnotalwaysfollowed
tomoveasmalltransducerattachedtoanarticulatedarm astraight-line.However,untilthenexttechnologicalad-
acrosspatient’sabdomeninordertocreateacomposite vancesetsoffanewsetofchallenges,mostoftheclinical
imagefromdatastoredduringthesweep.Thefirstma- kinkshavebeenironedouttoapointwhereabookcan
chineweusedatYalewasasurprisinglysmallunitmadeby nowbewrittentolayoutthestateofcontemporaryknowl-
Pickerthatwasdonatedbyagratefulpatientofthechair- edgeinobstetricalultrasound.
manatthattime,C.LeeBuxton,whofeltthattheremight Otherthanacursorymentionofthepastinthisintro-
afutureforultrasoundinobstetricsandgynecology(after duction,theonlyhistoricalinsertswillbeusedtodispela
hearingalecturebythefatherofobstetricalultrasound, fewearliermisconceptionsortodoawaywithsomemis-
IanDonald).Also,hisinterestwaskindledfurtherbyDr guidedritualsthathavecreptintoultrasoundpracticeover
ErnestKohorn,aBritishtransplantinthedepartmentwho thepasttwodecades.
hadspenttimewithProfessorDonald. Incontrasttoourfirstbooks,thechallengenowisto
In 1975, Jim Binns, a young representative from a siftthroughthemyriadofavailableclinicalinformation
fledglingcompany,ADR,stoppedbywithasmallreal-time andtocramselectivelythemostusefulnuggetsintothis
machinethatcouldalmostfitinasuitcase.Thereal-time text.Theformatwillbesimple,butdifferentthanother
imagesspringingfromthismachinehadthesamewowef- standardtextbooks.Whileavoiding“textbookspeak,”I
fectonusthatthefour-dimensionalreal-timeimagesfrom willbeworkingbackwardfromatopicbyfocusingona
today’smachineshaveonpatients,andweinstantlyhad specificconditionoraninitialfindingnotedduringabasic
toownit.Thisweaccomplishedwithacheckfor$20,000. examinationandexploringhowultrasoundcanbeused
Afewyearslater,thissimplelineararraytechnologymor- optimally to attain the clinician’s goal of arriving upon
phedintothecomplicated,expensive,andoftencumber- adiagnosisandactivatingaplanofmanagement.While
some units of today that, fortunately, produce exquisite attempting to be succinct, I have avoided including vo-
images.Injustadecade,thepriceofthesemachineshas luminousreferencesectionsaftereachchapter,andhave
gonefromthatofaMazdaMiatatoaLamborghini,and, triedtobejudiciouslyselectivebycitingmostlythosepa-
whileduringthetimeittooktoreducethesizeofacom- perswhosedataIhaveusedinthetext.
putertosomethingyoucanencloseinyourhand,many The goal is to inform—but with a heavy dusting of
oftoday’sultrasoundmachines,whichironicallydepend opinion.
heavilyonmicrochiptechnology,aresoheavythatIlivein
fearthatImightaccidentallyrunoneovermyfoot.Inad- JohnC.Hobbins,MD
dition,becausethenewmachinesincorporatemanynew February2007
ix
BLUK104-Hobbins August17,2007 17:23
1
Early pregnancy loss
Mostperinatologistsdealmorefrequentlywithpatients of 1 mm a day, and the mean sac diameter (MSD) can
duringthesecondportionofthefirsttrimester,andIam beusedasagaugeagainstwhichtoassessotherfindings
noexception.Forthatreason,whiledraftingthischapter [1].Bewareofthepseudosac,whichdoesnothaveadou-
I needed help with the topics of early pregnancy mile- bleringandisseeninassociationwithectopicpregnancy
stonesandthecommonproblemofearlyfirsttrimester (Figure1.1b).
embryonic/fetalloss.Afterabriefsearch,Icameupwith The yolk sac is the second structure to be visible by
a gem in the form of syllabus material accompanying a ultrasound (Figure 1.2). It can be seen when the MSD
superb lecture by Dr Steven Goldstein, given at an ul- is 5 mm, but it should be seen by the time the MSD is
trasoundcourse.Thiswillbesprinkledthroughoutthis 8mm[2].Itplaysacrucialroleinthedevelopmentofthe
chapter. fetus—providing nourishment and producing the stem
Earlypregnancycanbedividedupintothreesegments: cellsthatdevelopintoredbloodcells,whitebloodcells,
the pre-embryonic period (conception to 5 menstrual andplatelets.Ineffect,theyolksacprovidestheimmuno-
weeks);theembryonicperiod,duringwhichtimeorgano- logical potential for the fetus until about 7 menstrual
genesisisthemajoractivity(4–9menstrualweeks);and weeks, when those functions are taken over by the fetal
the early developmental period, during which time the liver.Fromthenonthefunctionlessyolksacbecomesa
fetus simply grows while adding to the building blocks circularstructurewithoutacore,afterwhichitfinallydis-
formedearlier(10–12weeks).Notsurprisingly,thethird appearsby12menstrualweeks.
segmenthasbeencalledthefetalperiod. Afterabout8weeks,theyolksachaslittlediagnostic
value and, although some studies have suggested that a
macroyolksac(morethan6mm)isanominoussign,our
Ultrasoundmilestones ownobservationshavenotbornethisout.Wehavenoted
a“filledin”yolksac(Figure1.3)tobesometimesassoci-
First,itmustbestipulatedthatthereisamajordifference atedwithfetaldemise,butinthesecasestheembryo/fetus
betweenwhenacertainfindingcanappearandwhenit providestheultimateinformation.
shouldbepresent,thelatterhavingmoreimportancein One can see an embryo by 5 menstrual weeks and a
earlypregnancyfailure.Also,onecanidentifystructures waytodeterminegestationalageistoadd42daystothe
much earlier with transvaginal ultrasound, which has a crown–rumplength(CRL)measurementinmillimeters.
separate timetable. Frankly, up until the eleventh week, TheembryoshouldincreaseitsCRLby1mm/d.Notseeing
there is little reason to view a first trimester pregnancy anembryowhentheMSDhasreached6mmisindicative
withtransabdominalultrasound(TAU)otherthanasan ofapregnancyloss[3].Also,thesizeoftheembryo,relative
initialquickscoutingventure. totheMSD,isimportant.Forexample,iftheMSD–CRL
The first ultrasound sign of pregnancy is a gesta- is<6mm,theprognosisisverypoor.
tionalsacthatisgenerallyoblongandhasathick“rind” Cardiacactivityshouldbevisualizedwhentheembry-
(Figure1.1a).Thesacshouldhaveadoublering,repre- onic length is greater than or equal to 4 mm, and not
sentingthedeciduacapsularisandthedeciduaparietalis, seeingabeatingheartatthisembryonicsizeisanomi-
andshouldbeseenwhenthebetahumanchorionicgo- nous sign [4]. The heart rate itself may provide insight
nadotropin (hCG) is between 1000 and 2000 mIU/mL. intothefateofthepregnancy.Forexample,Bensonand
Once seen, the sac diameter should grow by an average Doubilet[5]notedthatiftheheartrate(HR)waslessthan
ObstetricUltrasound:ArtistryinPractice.JohnC.Hobbins.Published2008BlackwellPublishing.ISBN978-1-4051-5815-2.
1
BLUK104-Hobbins August17,2007 17:23
2 Chapter1
(a)
Fig1.2 Yolksac.
(b)
Fig1.3 Filled-inyolksac;calipersareonCRLandarrowpoints
Fig1.1 (a)Earlygestationalsac.(b)Ectopic.Largearrowpoints
toyolksac.
topseudosac.Smallarrowpointstoectopicnexttouterus.
trimester. Although various investigators have explored
90inpregnanciesthatwerelessthan8weeks,therewasan subunitsofthehCGmoleculeinscreeningforDownsyn-
80%chanceoffetaldeath.IftheHRwasbelow70,100% drome (beta subunit), the assays commonly used today
ultimately had an intrauterine demise. Later in the first forstandardmonitoringofearlypregnancymeasurein-
trimester,fetuseswithHRabovethe95thpercentilehave tacthCG(notbetahCG).
amarkedlyincreasedriskfortrisomy13[6].
ShouldseeonTVS Timeofvisualization
Humanchorionicgonadotropin(hCG) Gestationsac 5menstrualweeks
Yolksac whenMSDis>7mm
Thisisaproductoftheplacentathatriseslinearlythrough- Embryonicpole 5weeksorwhenhCGis>1000mIU
outthefirsttrimesteranddecreasesthroughthesecond Fetalheartactivity whenCRLis>5mm