7 July, 2003 AZ/Manchester Knees Meeting 1 AstraZeneca & University of Manchester Knees Project...
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Transcript of 7 July, 2003 AZ/Manchester Knees Meeting 1 AstraZeneca & University of Manchester Knees Project...
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 11
AstraZeneca & University of AstraZeneca & University of ManchesterManchester
Knees ProjectKnees Project
Project MeetingProject Meeting
ISBE, University of ISBE, University of ManchesterManchester
77thth July 2003 July 2003
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 22
BackgroundBackground
Measure cartilage Measure cartilage changes during changes during osteoarthritis osteoarthritis disease disease progressionprogression
LocalisedLocalised Global measures Global measures
insufficientinsufficient Cartilage Volume, Cartilage Volume,
Mean ThicknessMean Thickness Dense set of Dense set of
measuring pointsmeasuring points
Sub-MillimetreSub-Millimetre Combine data from a Combine data from a
population of patientspopulation of patients Cartilage UnstableCartilage Unstable
Use the underlying Use the underlying bone as the frame of bone as the frame of referencereference
CP78 DataCP78 Data 45 Patients at 45 Patients at
Baseline and 6 MonthsBaseline and 6 Months Cartilage and Bone Cartilage and Bone
SegmentationsSegmentations
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 33
Statistical Shape Model Statistical Shape Model (SSM)(SSM)
Concise description a set of shapesConcise description a set of shapes Set of points on each exampleSet of points on each example Vectors of how these points vary Vectors of how these points vary
between examplesbetween examples Best Model Best Model Anatomically Anatomically
Corresponding PointsCorresponding Points Means of combining and comparing Means of combining and comparing
individual measurements between individual measurements between any two or more examplesany two or more examples
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 44
Statistical Shape ModelStatistical Shape Model
Amy Bone SegmentationsAmy Bone Segmentations Full setFull set Insufficient coverage of bone Insufficient coverage of bone
shaftshaft Lisa Bone SegmentationsLisa Bone Segmentations
Full TP1 but limited TP2Full TP1 but limited TP2 Bone shaft includedBone shaft included
Use Lisa TP1 Bone Use Lisa TP1 Bone SegmentationsSegmentations Register TP1 Bone with TP2 Register TP1 Bone with TP2
CartilageCartilage
50 60 70 80 90 100 110
70
80
90
100
110
120
130
140
150
X
AB121247_a2BFem
Y
50 60 70 80 90 100 110
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X
AB121247_l2BFem
Y
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 55
Model ConvergenceModel Convergence
Population size Population size 3636
1026 1026 Correspondence Correspondence PointsPoints
Processing time Processing time 10hrs10hrs
0 1000 2000 3000 4000 5000 6000 7000 8000 9000-140.8324
-140.8323
-140.8322
-140.8321
-140.832
-140.8319
-140.8318
-140.8317
-140.8316Objective Value Convergence n=36
Obj
ectiv
e V
alue
Iterations
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 66
Corresponding PointsCorresponding Points
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 77
Shape ModelShape Model
Mode 1 Mode 2
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 88
Visualisation ToolsVisualisation Tools
Interactive examination of the Interactive examination of the corresponding pointscorresponding points
Useful to validate the modelUseful to validate the model
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 99
-1 -0.5 0 0.5 1 1.5 2-2
-1.5
-1
-0.5
0
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1.5
2
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Z
Validation using Synthetic Validation using Synthetic ShapeShape
Synthesised Brick and Bump shapeSynthesised Brick and Bump shape Control correspondences’ positionsControl correspondences’ positions Validate automatic 3D shape buildingValidate automatic 3D shape building
Analogous to to moving bump in 2DAnalogous to to moving bump in 2D
-1 -0.5 0 0.5 1 1.5 2-2
-1.5
-1
-0.5
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-1 -0.5 0 0.5 1 1.5 2-2
-1.5
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-0.5
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-1 -0.5 0 0.5 1 1.5 2-2
-1.5
-1
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-1 -0.5 0 0.5 1 1.5 2-2
-1.5
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Z
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1010
TibiaTibia
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1111
PatellaPatella
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1212
Surface ConstructionSurface Construction
Currently using ‘Spans & Ridges’Currently using ‘Spans & Ridges’ Semi-Automated, Robust, Versatile Semi-Automated, Robust, Versatile Reliable thickness measurementsReliable thickness measurements Not continuous or smoothNot continuous or smooth
Smooth surface constructionSmooth surface construction 3D Surface interpolation3D Surface interpolation More accurate cartilage representation More accurate cartilage representation
and thickness measurementsand thickness measurements
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1313
Surface ConstructionSurface Construction
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1414
Surface ConstructionSurface Construction
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1515
Image/Surface Image/Surface RegistrationRegistration
Corrects for Chemical Shift ArtefactCorrects for Chemical Shift Artefact Corrects any movement between Corrects any movement between
successive Bone and Cartilage scanssuccessive Bone and Cartilage scans Deals with inadequate set of TP2 bone Deals with inadequate set of TP2 bone
segmentationssegmentations Register TP1 Bone scan with TP2 Cartilage scanRegister TP1 Bone scan with TP2 Cartilage scan Halves the number of training examplesHalves the number of training examples
Weakest linkWeakest link Approximately 80% successfulApproximately 80% successful
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1616
Rigid Image RegistrationRigid Image Registration
Slices 10 to 18 Region of Region of Interest Interest determined by determined by bone bone segmentationsegmentation
Mutual Mutual Information used Information used as quality as quality measure of measure of matchmatch
Steepest descent Steepest descent search algorithmsearch algorithm
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1717
Bone and Cartilage Surface Bone and Cartilage Surface RegistrationRegistration
Measure Cortical Bone ThicknessMeasure Cortical Bone Thickness Distance along bone 3D normal to inner Distance along bone 3D normal to inner
cartilage surfacecartilage surface Mean, Standard Deviation and Range give Mean, Standard Deviation and Range give
quality measure of registrationquality measure of registration
MC04MC04TP1TP1Mean: 0.92Mean: 0.92StdDev: StdDev: 0.6890.689
TP2TP2Mean: -0.61Mean: -0.61StdDev: StdDev: 1.7661.766
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1818
Bone-Cartilage Bone-Cartilage RegistrationRegistration
Persevere with automatic approachesPersevere with automatic approaches Image Registration 80% successImage Registration 80% success Surface RegistrationSurface Registration distorts Cortical Bone distorts Cortical Bone
thicknessthickness EndPoint Active Shape ModelEndPoint Active Shape Model
Builds model of intensities around TP1 Builds model of intensities around TP1 surfacesurface
Matches model to TP2 imageMatches model to TP2 image Initial tests promisingInitial tests promising
Segment Time point 2 boneSegment Time point 2 bone
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 1919
Thickness MapsThickness Maps Thickness measured along 3D Thickness measured along 3D
normal to bone surfacenormal to bone surface Measurements at the Corresponding Measurements at the Corresponding
PointsPoints
Bone surface
Cartilage inner surface
Cartilage outer surface
3D Normal to bone surface at correspondence point
Cartilage Thickness
Cartilage Thickness = Cartilage Thickness = distance between distance between intersections of the intersections of the normal with the inner normal with the inner and outer cartilage and outer cartilage surfacessurfaces
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2020
Thickness Thickness MeasurementsMeasurements
Choose valid Choose valid correspondence pointscorrespondence points 50% of correspondence with 50% of correspondence with
cartilage presentcartilage present 0 thickness if cartilage not 0 thickness if cartilage not
presentpresent Distance along 3D normal Distance along 3D normal
of bone surface to inner of bone surface to inner and outer cartilage and outer cartilage surfacessurfaces
Measurements Measurements aggregated and aggregated and comparedcompared Average from all examples Average from all examples
including 0 thicknessincluding 0 thickness
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2121
Pair-wise Thickness Pair-wise Thickness MapsMaps
Examine changes in thickness in Examine changes in thickness in individual patientsindividual patients
AB121247 Cartilage Thickness TP1 and AB121247 Cartilage Thickness TP1 and TP2TP2
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2222
Pair-wise Thickness Pair-wise Thickness MapsMaps
DA030535DA030535
JD190847JD190847
RG271036RG271036
SP190445SP190445
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2323
Corresponded Thickness Corresponded Thickness MapsMaps
TP1: 1.768 TP2: 1.753TP2-TP1: -0.0156
(N = 28 Lisa Bone, Amy Cartilage)
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2424
Patient DifferencesPatient DifferencesDA030535DA030535
JD190847JD190847
RG271036RG271036
SP190445SP190445
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2525
Confidence MeasuresConfidence Measures
Standard Deviation of Standard Deviation of corresponding corresponding differences across differences across populationpopulation
T-Test: mean(TP1)-mean(TP2) / T-Test: mean(TP1)-mean(TP2) / var(TP1)+var(TP2)var(TP1)+var(TP2)
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2626
CP78 Work-PlanCP78 Work-Plan
DevelopmenDevelopmentt
1010
Reduced SetReduced Set
3232Full SetFull Set
(45)(45)
FemurFemur July 03July 03
TibiaTibia July 03July 03 Aug 03Aug 03
PatellaPatella Aug 03Aug 03 Aug 03Aug 03
Bones
Set Size
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2727
Future WorkFuture Work Improved Image RegistrationImproved Image Registration Statistical AnalysisStatistical Analysis Extend to Tibia and PatellaExtend to Tibia and Patella Amy and Lisa Cartilage SegmentationsAmy and Lisa Cartilage Segmentations Smooth Cartilage and Bone Surfaces Smooth Cartilage and Bone Surfaces Third Party ValidationThird Party Validation ImorphicsImorphics
Incorporation into EndPointIncorporation into EndPoint Automatic Segmentation and AnnotationAutomatic Segmentation and Annotation Extend to other anatomical regionsExtend to other anatomical regions
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2828
CP77 Bone CP77 Bone SegmentationSegmentation
Complete set of Bone Complete set of Bone scansscans 5 x 3 + 15 x 1 = 305 x 3 + 15 x 1 = 30 6 man days6 man days
CP77 Bone CP77 Bone SegmentationSegmentation Funding and Funding and
RecruitmentRecruitment Use current resourcesUse current resources
1001LR1L slice 40
50 100 150 200 250
50
100
150
200
250
1001LR2L slice 40
50 100 150 200 250
50
100
150
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250
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 2929
PublicationsPublications Preliminary ResultsPreliminary Results
MIUA Sheffield PosterMIUA Sheffield Poster IPMI Ambleside PosterIPMI Ambleside Poster MICCAI MontrealMICCAI Montreal
CP78 Bone Model Disease ProgressionCP78 Bone Model Disease Progression Method (Image Processing Journal)Method (Image Processing Journal) Results (Medical Journal)Results (Medical Journal)
CP77 Normal RangeCP77 Normal Range
7 July, 20037 July, 2003 AZ/Manchester Knees MeetingAZ/Manchester Knees Meeting 3030
Publication PlanPublication PlanPaperPaper DisclosuresDisclosures TargetTarget DateDate Main Main
AuthorAuthorss
Shape Shape Model Model PreliminaryPreliminary
SSM, Bone SSM, Bone Reference, Reference, Corresponded Corresponded Thickness MapsThickness Maps
Image Image ProcessinProcessing Conf.g Conf.
June June 20032003
ISBEISBE
Normal Normal RangeRange
CP77 normal range CP77 normal range of cartilage of cartilage thickness and thickness and coveragecoverage
Image Image ProcessinProcessing Conf.g Conf.
October October 20032003
ISBEISBE
Shape Shape Model Model MethodMethod
All compartments, All compartments, full population full population thickness maps, thickness maps, statistical analysis statistical analysis
Image Image ProcessinProcessing Journalg Journal
NovembeNovember 2003r 2003
ISBEISBE
OA Disease OA Disease ProgressioProgressionn
Corresponded Corresponded thickness maps, thickness maps, clinical information, clinical information, disease progression.disease progression.
OA/OA/
Medical Medical JournalJournal
NovembeNovember 2003r 2003
AZAZ