Combining the strengths of UMIST and The Victoria University of Manchester Focal Analysis of Knee Articular Cartilage Quantity and Quality Project Meeting April 19 th, 2005 ISBE, University of Manchester

Combining the strengths of UMIST and The Victoria University of Manchester Contents Previous Meeting’s Minutes CP77 –Methodology paper –Additional Statistical Analysis CP78 –Multivariate analysis results –Region of Interest Definitions –Cartilage Morphology Measurements –Proposed Analyses Time Scales Follow-on Projects

Combining the strengths of UMIST and The Victoria University of Manchester CP77 Methodology Paper Figures –flow-chart and re- parameterisation –Colour or Gray scale Clarifications –No duplicate bone segmentations –‘Tessellation’ Statistical Analysis –Aggregate measures restricted to single scan per subject –Normal range definition –Difference analyses Intra-segmentor Inter-segmentor Side: Left / Right –Duplicate volume ANOVA analysis

Combining the strengths of UMIST and The Victoria University of Manchester CP77 Coverage Ti [-5,10] Ti_theta [0,π/4] Th [0,20] 90% Coverage Percentage Coverage

Combining the strengths of UMIST and The Victoria University of Manchester CP77 Normal Range 4 duplicate cartilage segmentations for all 19 subjects Mean SD CoV

Combining the strengths of UMIST and The Victoria University of Manchester CP77 Full Range

Combining the strengths of UMIST and The Victoria University of Manchester Difference Analyses ‘N’ ‘S’ Intra-Segmentor Inter-Segmentor Inter-Scanner

Combining the strengths of UMIST and The Victoria University of Manchester Additional Statistical Analyses Normal Range Statistics Trimmed volume for comparison with Shetha’s paper Mixed-effects ANOVA Side Differences

Combining the strengths of UMIST and The Victoria University of Manchester CP78 Multivariate Results SwellingThinning 95% Confidence Interval Mean Thickness Change Evidence of real difference between baseline and 6 months using permutation tests. P=0.01

Combining the strengths of UMIST and The Victoria University of Manchester CP78 Region of Interest Definitions Coverage –Maximal [Max] (Limits of functional regions) –Expected [Exp] (CP77 90% coverage) –Trimmed [Trm] (Eliminate uncertainty of edges)

Combining the strengths of UMIST and The Victoria University of Manchester CP78 Region of Interest Definitions Whole Cartilage NomenclatureCoverage Level 1Level 2MaxExpTrm FemurTrFcTrF lTrF mTrF LFcLF pLF MFcLF pLF PatellacP lP mP TibiaLT MT

Combining the strengths of UMIST and The Victoria University of Manchester RoI Definition Tool

Combining the strengths of UMIST and The Victoria University of Manchester Functional Definitions TrF LF MF cTrF lTrF mTrF pLF cLF

Combining the strengths of UMIST and The Victoria University of Manchester Functional Definitions lP mP cP LT MT

Combining the strengths of UMIST and The Victoria University of Manchester Cartilage Morphology Labels Modifiers –t: total –c: covered by cartilage –d: denuded of cartilage (d+c=t) Geometric –A: Area –V: Volume –Th: Thickness –N: Count of lesions Shape Identifiers –[In]: Individual –[Av]: average/mean shape Tissue –B: Bone –C: Cartilage Examples tA[Av]B Total surface area of the average bone cAInB Cartilage Covered Bone Area of an individual –Covered area = proportion of covered vertices Report region for mean thickness –ThCtAB: Mean thickness for total area. Areas include dAB where ThC=0

Combining the strengths of UMIST and The Victoria University of Manchester Volume vs. Integrated Thickness VC Cartilage Volume (ml) –Compute using Green’s Theorem –Partition required for regional analysis –Inevitable overlap and exclusion of volume [ITh] Integrated Thickness (mm 3 ) –Sum of facets’ mean cartilage thickness times surface area –[ITh] = ∑ AB · ThC = ∑ × –Patella and Tibia:  Planar  Reasonable approximation –Femur: Covex  Underestimation Error (ITh-VC)(%) PFT Mean-2.14%-10.80%1.52% Std6.02%3.54%3.61%

Combining the strengths of UMIST and The Victoria University of Manchester Normalised Measures VCtAB = VC / tA[In]B: Volume normalised by individual’s bone surface area VC replaced by integrated thickness: A[In]B · ThC We can use the mean bone shape’s surface area as the normalisation constant –A[Av]B · ThC Proposed Measures –Areas: cA[In]B, cA[Av]B –Volumes: VC, CTh · A[In]B, CTh · A[Av]B

Combining the strengths of UMIST and The Victoria University of Manchester Priorities and Time Lines CP77 Methodology Paper (May) –Additional statistical analyses CP78 Region of Interest Volume Analysis –Partitioned volume or Integrated thickness (+2 weeks) –Requirement Specification (Apr) –Dissemination and publication (May) CP78 Multivariate Thickness Analysis (June+) Publication plan –Journal publications

Combining the strengths of UMIST and The Victoria University of Manchester Follow-on Projects Method Development –Parameterised surfaces from parallel slice segmentations –Fully automated bone and cartilage segmentation –Large trial analysis –Per-patient analysis tool Collaborators Funding –Stepping stone