ter Haar Romeny, FEV MIT AI Lab Automatic Polyp Detection

ter Haar Romeny, FEV Enhancement by Gaussian curvature PMS CT slice with tagged residual sticking to the wall Same slice after electronic cleansing Philips MS Electronic colon cleansing

ter Haar Romeny, FEV Current visualization Normal dose Smooth surface Low dose Blobs appear Normal dose Rough surface

ter Haar Romeny, FEV Proposed solutions Bilateral filtering  blobs Gradient smoothing  rough surface

ter Haar Romeny, FEV Results: normal dose

ter Haar Romeny, FEV Results: all dose levels 1.6 mAs 6.25 mAs64 mAs

ter Haar Romeny, FEV Extract vasculature with ‘vesselness’ From T1w MRI with contrast Frangi’s vesselness measure [Frangi et al., 1998] Enhance tubular structures while reducing other morphologies E. Brunenberg, MSc project

ter Haar Romeny, FEV Vesselness measure Based on eigenvalue analysis of Hessian: two low eigenvalues one high eigenvalue

ter Haar Romeny, FEV Vesselness - 1 Eigenvalue analysis of Hessian: extract directions of principal curvature Hessian: where and

ter Haar Romeny, FEV Vesselness - 2 Eigenvalues ordered as | λ 1 | ≤ | λ 2 | ≤ | λ 3 | Bright vessel region: λ 1 small, ideally zero; λ 2 and λ 3 large but negative. Ratio for blobness: Ratio for plate-like: Image structure:

ter Haar Romeny, FEV Vesselness - 3 Total vesselness function: Parameters: α = β = 0.5 c = 0.5 * maximum Hessian norm Multiscale approach:

ter Haar Romeny, FEV Vessel enhancement filtering Better delineation of small vessels Preprocessing before MIP Preprocessing for segmentation procedure

ter Haar Romeny, FEV Abdominal MRA Maximum intensity projection No 3D information Overlapping organs

ter Haar Romeny, FEV 2D Example: DSA

ter Haar Romeny, FEV Scale integration

ter Haar Romeny, FEV Closest Vessel Projection

ter Haar Romeny, FEV Trabecular Bone Bone appears in two forms Cortical Bone Trabecular Bone connected network of rods & plates loading dependent architecture Wiro Niessen, PhD

ter Haar Romeny, FEV Stress routes Wolff’s Law “The internal structure and external shape of a bone develop in response to the change in function and forces acting upon it” Culman Meyer “Trabecular pattern is oriented with routes of stress”

ter Haar Romeny, FEV Clinical Relevance Trabecular Architecture important parameter in bone strength (clinically proven) Applications for in vivo analysis determine fracture risk monitoring structure in aging monitor degree and development of osteoporosis (treatment available) monitoring malgrowth near epiphyses placing implants and evaluating receipt

ter Haar Romeny, FEV

Stress Routes in Ankle

ter Haar Romeny, FEV MR Ankle, FFE, short TE (300  m)

ter Haar Romeny, FEV CT dry femur (250  m)

ter Haar Romeny, FEV Structural Information

ter Haar Romeny, FEV 3D orientaties

ter Haar Romeny, FEV Dominant orientations Orientations preferentially along anatomical axis Histogram of 3D directions: