Table Of ContentCT Colonography
A Guide for Clinical Practice
ThomasMang,MD
AssociateProfessorofRadiology
DepartmentofRadiology
MedicalUniversityofVienna
Vienna,Austria
WolfgangSchima, MD,MSc
ProfessorofRadiology
HeadofDepartmentofDiagnosticand
InterventionalRadiology
KrankenhausGoettlicherHeiland
KrankenhausderBarmherzigenSchwesternWienand
Sankt-Josef-Krankenhaus
Vienna,Austria
WithcontributionsbyAnnoGraser
535illustrations
Thieme
Stuttgart (cid:127) New York
IV
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V
Foreword
Colorectal cancer is the third mostcommon malignancy The breadth of progress in CT colonography over the
worldwideandthesecondleadingcauseofcancerdeaths last decade mandates publication of this textbook. CT
in North America, the United Kingdom, and Australasia. Colonography: A Guide for Clinical Practice is a much
Althoughtheincidenceofcolorectalcancerhasincreased needed comprehensive, authoritative, and wide-ranging
steadily over the past five decades, recent trends have overview of the current state of this imaging modality.
shown a reduction in mortality which is believed to be Although the illustrations and graphics are superb, this
due to screening and improved chemotherapy and sur- bookissomuchmorethananatlasofillustrativecases.It
gery.Nevertheless,thechallengetodiminishtheburden includes chapters addressing: indications, contraindica-
ofcolorectalcancerremainsunabated.Givenourunder- tions, and risks of the procedure; detailed instructions
standingofthetumorpathogenesis,tumorgenetics,and concerning patient preparation, exam performance and
effective preventive interventions, colorectal cancer optimization; tips for data analysis and interpretation
shouldbepreventableinmostcases.Thekeytofulfilling strategies; normal anatomy, polyps, cancers, flat lesions,
this goal is early detection of the cancer or better yet, benign disorders, pitfalls and artifacts; staging informa-
findingtheprecursorpolypbeforeitbecomesmalignant. tionforcolorectalcancerandsurveillanceaftercolorectal
To this end, a number of indirect and direct screening surgery;and screening programs and training. Very im-
modalities have been developed. Indirect tests include portantly, this book provides explicit advice for produc-
stool-based tests for occult blood, immunochemical and ingaclinicallyusefulreport(C-rads),handlingextra-co-
DNAanalysis,andserum-basedmarkersincludingserum lonic findings, and reducing radiation dose, and clearly
proteomics, nuclear matrix proteins, and serum DNA describestheroleofcomputer-assisteddetectionofpol-
testing. The direct screening tests are barium enema, yps and intravenous contrast material in this examina-
flexiblesigmoidoscopy,opticalcolonoscopy,andmostre- tion.Keypointsareemphasizedwithcoloredinformation
cently CT colonography. Dramatic advances in CT colo- boxes.
nography have made this technique a highly sensitive, Thisworkwillbeofvaluetoallphysiciansconcerned
specific, noninvasive, and clinically attractive means of with the challenges of colorectal cancer. Drs. Mang and
detecting colonic adenomas and polyps. In view of the Schimadeservecongratulationsforproducinganinvalu-
surfeit of CT scanner capacity and the finite number of able resource that is comprehensive and, at the same
gastroenterologists with colonoscopes, CT colonography time,userfriendlyandpractical.
perhaps is the only practical means to directly screen
large populations at risk, namely individuals over the RichardM.Gore,MD,FACR,FACG
ageof50years. UniversityofChicago
Chicago,Illinois,USA
VI
Preface
CTcolonography,alsoknownasvirtualcolonoscopy,isa mentbytheEuropeanSocietyofAbdominalandGastro-
minimally invasive technique that enables evaluation of intestinalRadiology(ESGAR).Appropriateindicationsfor
theentirecolon.Variousstudieshaveconfirmedtheuse- theuseofCTcolonographyarepresented,asarecommon
fulnessofCTcolonographyasareliablenewmethodfor protocolsforpatientpreparationandCTdataacquisition.
detectionofcolorectalpolypsanddiagnosisofcolorectal The emphasis is on examination protocols that may be
carcinomas. Its use is also indicated in some other con- easily applied in clinical practice. There is also a broad
ditions,specificallyafterincompleteopticalcolonoscopy. discussionofanalysistechniquesaswellasvariousinter-
InrecentyearsCTcolonographyhasbecomeawidely pretation strategies including computer-aided detection.
used method, no longer a specialized diagnostic proce- In the diagnostic part, the book turns to a systematic
dureperformedonlyatacademiccenters.Thistrendmay discussion of the basic knowledge needed for proper
beexpectedtocontinueinthecomingyears,andtheuse diagnosis.Thisincludesknowledgeofnormalcolonicap-
ofCTcolonographywillbecomeincreasinglycommon. pearances on CT, followed by a discussion of common
Experiencehasshownthatthequalityoftheexamina- diseases,withaclear,detailed,point-by-pointdiscussion
tionandoftheevaluationoffindingslargelydependson of specific and nonspecific two-dimensional and three-
theexpertiseoftheexaminer.Thelearningprocessmay dimensionaldiagnosticcriteriaanddifferentialdiagnoses.
beacceleratedbothbyspecializedtrainingandbybooks Evaluationanddifferentialdiagnosticcriteriaarefurther
devotedtothesubject.Recognizingthisiswhatprovided illustratedbyabundant images.Thisallowsreaderswho
theimpetusforustowriteabookthatwouldbeakindof areinterestedinlearningmoreaboutCTcolonographyto
“user’smanual”forCTcolonography. quicklygainadetailedoverviewofthetechnique.Those
Thepresentbookisintendedtogivethereaderacon- with more experience have the opportunity to expand
cise overview of useful examination techniques and a and deepen their knowledge. Finally, readers are also
systematic approach to interpreting findings correctly. givenhelpfultipsondocumentationandpresentationof
Thefocusisondifferenttechniquesthatarequicklyand findings.
easily applied both in the in-patient and in the out- Theideaforthisbookdevelopedoutofnumerouscon-
patient setting. For readers who are less familiar with tinuingeducationandtrainingseminarsforphysicians.It
this exciting technique, this book provides a simple and isbasedonapracticaltrainingcourseinCTcolonography
focused introduction to CT colonography and facilitates thatisofferedattheMedicalUniversityofVienna.
its use. The experienced examiner, too, will find tips on We hope that this book will educate readers in the
howtoimprovetheexaminationandavoidcommonpit- principles of CT colonography in a clear and practical
fallsinevaluation. fashion and will thus help this new method to be used
The book is divided into two parts. The methods sec- tothebenefitofthepatient.
tion deals with current examination and interpretation
techniques used in CT colonography. The information
presented is in accordance with the currently accepted ThomasMang
technicalguidelinesaspublishedintheconsensusstate- WolfgangSchima
VII
Acknowledgments
Thisbookwouldnothavebeenpossiblewithoutthesup- Numerouscolleaguesinthefieldkindlysuppliedaddi-
port of Georg Thieme Verlag and the kind and expert tional image material. We would like to thank: Gernot
assistance of its employees. The following employees of Böhm (Linz), Rosa Bouzas (Vigo), Wolfgang Dock (Vien-
Thieme Verlag helped in the realization of this project: na), Frans-Thomas Fork (Malmö), Thomas Hackländer
Susanne Huiss, Dr. Antje Merz-Schönpflug, Rolf Zeller, (Wuppertal), Johann Hammer (Vienna), Helmut Ringl
and Dr. Christian Urbanowicz. For the English edition (Vienna), Andrew Slater (Oxford), and Damian Tolan
wespecificallywant tothankGabrieleKuhn-Giovannini, (Leeds).
Sophia Hengst, Stephan Konnry, and the freelance copy For medical advice and constructive comments, we
editor Kersti Wagstaff. They successfully applied our would like to thank Helmut Gruber (Vienna), Andrea
ideas concerning content and layout and offered their Maier (Vienna), Martin Riegler (Vienna), and Mathias
support during every phase of the project, helping to Prokop(Nijmegen).
creativelydevelopthis book.Theyimplementedour nu- We are also grateful to our documentation assistant,
merous suggestions and modifications to the revised Ines Fischer, who assisted with processing the graphics.
manuscript for the English edition with an abundance WealsothankKarinNeckar,MargitSandner,PetraLach,
ofpatience.Wearegratefultothemfortheirassistance. and Michael Kalas, who helped with the preparation of
WewouldalsoliketothankProfessorChristianHerold, themanuscript.
ChairmanoftheDepartmentofRadiologyattheMedical
UniversityofVienna,whosupportedthedevelopmentof ThomasMang
CT colonographyat this University, and also the present WolfgangSchima
bookprojectfromitsbeginning.
VIII
Table of Contents
1 Indications and Contraindications 1
Indications ............................ 1 Contraindications ...................... 6
DiagnosticCTColonography ............... 1
ScreeningCTColonography ............... 5
2 Examination 9
PatientPreparation..................... 9 PositioningthePatient ................... 23
StandardBowelPreparationProtocol ........ 9 CTScoutImage ......................... 25
MarkingStoolandResidualFluid
(Fecal/FluidTagging) ..................... 13 CTExaminationTechnique .............. 28
ReducedBowelPreparation ............... 17 MultidetectorCTProtocolsforCT
Laxative-Free(Noncathartic) Colonography........................... 28
CTColonography ........................ 18 IntravenousContrastMedia ............... 32
ESGARConsensusStatementonBowel
Preparation............................. 18 RiskProfileofCT Colonography.......... 36
Perforation ............................. 36
ColonDistension ....................... 18 CardiovascularEffects .................... 40
BasicPrinciplesandPreparation............ 19 RadiationExposure ...................... 40
DistensionTechnique..................... 21 Drug-InducedReactions .................. 40
3 Image Interpretation 43
DataAnalysisandInterpretationStrategies 43 TechniquesforMeasuringPolyps ........... 62
2DEvaluation........................... 43 InfluenceofFecalTagging................. 65
3DEvaluation........................... 47 DiscrepanciesbetweenCTColonographyand
PerformingtheEvaluation ................ 49 OpticalColonoscopyFindings .............. 65
3DApplications ........................ 52 Computer-AssistedDetectionofPolyps ... 66
Additional3DProjections ................. 52 Principles .............................. 66
3DTools ............................... 54 UseinPractice .......................... 70
Advanced3DVisualizationTechniques ...... 58 InterpretationStrategiesUsingCAD ......... 71
InfluenceonInterpretationTime ........... 73
PolypMeasurement .................... 62 WhattoBearinMindwhenUsingCAD ..... 74
CriteriaforCorrectMeasurementofPolyps... 62 FuturePerspectives ...................... 74
