TY - JOUR

T1 - Automatic quantification of tibio-femoral contact area and congruity

AU - Tummala, Sudhakar

AU - Nielsen, Mads

AU - Lillholm, Martin

AU - Christiansen, Claus

AU - Dam, Erik Bjørnager

PY - 2012

Y1 - 2012

N2 - We present methods to quantify the medial tibio- femoral (MTF) joint contact area (CA) and congruity index (CI) from low-field magnetic resonance imaging (MRI). Firstly, based on the segmented MTF cartilage compartments, we computed the contact area using the Euclidian distance transformation. The CA was defined as the area of the tibial superior surface and the femoral inferior surface that are less than a voxel width apart. Furthermore, the CI is computed point-by-point by assessing the first- and second-order general surface features over the contact area. Mathematically, it is the inverse distance between the local normal vectors (first-order features) scaled by the local normal curvatures (second-order features) along the local direction of principal knee motion in a local reference coordinate system formed by the directions of principal curvature and the surface normal vector. The abilities of the CA and the CI for diagnosing osteoarthritis (OA) at different levels (disease severity was assessed using the Kellgren and Lawrence Index, KL) were cross-validated on 288 knees at baseline. Longitudinal analysis was performed on 245 knees. The precision quantified on 31 scan-rescan pairs (RMS CV) for CA was 13.7% and for CI 7.5%. The CA increased with onset of the disease and then decreased with OA progression. The CI was highest in healthy and decreased with the onset of OA and further with disease progression. The CI showed an AUC of 0.69 (p ; 0. For separating KL ; 1 knees, the AUC for CI was 0.73 (p

AB - We present methods to quantify the medial tibio- femoral (MTF) joint contact area (CA) and congruity index (CI) from low-field magnetic resonance imaging (MRI). Firstly, based on the segmented MTF cartilage compartments, we computed the contact area using the Euclidian distance transformation. The CA was defined as the area of the tibial superior surface and the femoral inferior surface that are less than a voxel width apart. Furthermore, the CI is computed point-by-point by assessing the first- and second-order general surface features over the contact area. Mathematically, it is the inverse distance between the local normal vectors (first-order features) scaled by the local normal curvatures (second-order features) along the local direction of principal knee motion in a local reference coordinate system formed by the directions of principal curvature and the surface normal vector. The abilities of the CA and the CI for diagnosing osteoarthritis (OA) at different levels (disease severity was assessed using the Kellgren and Lawrence Index, KL) were cross-validated on 288 knees at baseline. Longitudinal analysis was performed on 245 knees. The precision quantified on 31 scan-rescan pairs (RMS CV) for CA was 13.7% and for CI 7.5%. The CA increased with onset of the disease and then decreased with OA progression. The CI was highest in healthy and decreased with the onset of OA and further with disease progression. The CI showed an AUC of 0.69 (p ; 0. For separating KL ; 1 knees, the AUC for CI was 0.73 (p

KW - biomedical MRI

KW - bone

KW - diseases

KW - medical disorders

KW - orthopaedics

KW - MRI

KW - OA progression

KW - automatic quantification

KW - congruity index

KW - contact area

KW - disease progression

KW - euclidian distance transformation

KW - femoral inferior surface

KW - first-order general surface features

KW - local normal curvatures

KW - local reference coordinate system

KW - longitudinal analysis

KW - low-field magnetic resonance imaging

KW - medial tibiofemoral joint contact area

KW - osteoarthritis

KW - principal curvature

KW - principal knee motion

KW - scan-rescan pairs

KW - second-order general surface features

KW - segmented MTF cartilage compartments

KW - surface normal vector

KW - tibial superior surface

KW - voxel width

KW - Biomechanics

KW - Equations

KW - Indexes

KW - Joints

KW - Magnetic resonance imaging

KW - Mathematical model

KW - Vectors

KW - Congruity

KW - knee osteoarthritis

KW - magnetic resonance imaging

KW - normal curvature

KW - Adult

KW - Aged

KW - Aged, 80 and over

KW - Algorithms

KW - Cartilage, Articular

KW - Case-Control Studies

KW - Disease Progression

KW - Femur

KW - Humans

KW - Knee Joint

KW - Magnetic Resonance Imaging

KW - Middle Aged

KW - Osteoarthritis, Knee

KW - Reproducibility of Results

KW - Tibia

U2 - 10.1109/TMI.2012.2191813

DO - 10.1109/TMI.2012.2191813

M3 - Journal article

VL - 31

SP - 1404

EP - 1412

JO - I E E E Transactions on Medical Imaging

JF - I E E E Transactions on Medical Imaging

SN - 0278-0062

IS - 7

ER -