conflicts of interest to report. Conflict of Interest Disclosure Amanda F. Khan, MSc. Medical Biophysics Has no real or apparent conflicts of interest to report.

A Novel MRI-Compatible Brain Ventricle Phantom for Software Validation Amanda F. Khan Department of Medical Biophysics Imaging Research Laboratories Robarts Research Institute The University of Western Ontario Supervisors: Dr. Michael Borrie, Dr. Robert Bartha Alzheimer’s Disease International – March 27h, 2011

The Ventricular System Lateral ventricles structures containing CSF in the midbrain atrophy of surrounding tissues leads to increase in CSF volume increase in CSF = increase in lateral ventricles (surrogate measure) capture this increase on MRI, sometimes years before cognitive decline can be measured Control AD 3D image adapted from: The Biodidac; MRI images from Wahlund LO, et al., J Neurol Neurosurg Psychiatry. 2000;69(5):630–635.

Brain Atrophy and Alzheimer’s How do we objectively quantify brain atrophy? How can we track ventricular expansion?

Volumetry and Alzheimer’s Segmentation programs objectively measure changes in ventricle volume = surrogate of brain atrophy uses seed placement and atlas systems potential to evaluate neuron saving potential of new AD drugs in clinical trials have not been reliably validated using physical models Control AD

Overview of the Phantom Model Purpose: to create a standardized, MRI compatible life-size phantom model of the human brain ventricles to evaluate segmentation methods utilizing 3T T1-weighed MRI 1 2 3 4

Ventricle Construction Pre-processed image Post-processed image ADNI 3T MRI image ADNI Image Database Software images from: The University of Pennsylvania

Ventricle Construction Digital mesh ITK-SNAP Rapid-prototyped lateral ventricles Fused Deposition Modelling

Tissue Model Series Description: MP-RAGE ADNI iPAT2 Axial Slice Thickness: 1.2mm Repetition Time: 2300ms Echo Time: 3ms Number of Averages: 1 Inversion Time: 900ms Flip Angle: 9˚ Width: 256mm Height: 240mm ROI Brain 2% agar ROI Ventricle Signal intensity (SI) difference = SI brain tissue – SI ventricle

Tissue Model Series Description: MP-RAGE Slice Thickness: 1.2mm Repetition Time: 2300ms Echo Time: 3ms Number of Averages: 1 Inversion Time: 900ms Flip Angle: 9˚ Width: 256mm Height: 240mm

Brain Ventricle Phantom 300mL “base” for proper midbrain positioning Completed brain-ventricle phantom model Slice Thickness: 1.2mm, Repetition Time: 2300ms, Echo Time: 3ms, Number of Averages: 1, Inversion Time: 900ms Flip Angle: 9⁰, Acquisition Width: 256mm Height: 240mm

Results Signal Intensity vs. Gadolinium Concentration Slice Thickness vs. Volume Accuracy

In-Vivo 3T Patient Scans Results Signal Intensity Properties In-Vivo 3T Patient Scans Phantom 3T Scans 261.5 SI units 262.9 SI units Volumetry Accuracy True Volume Phantom 3T Scans 47.7 cm3 47.2 cm3 3T MRI scans of completed phantom

Discussion cost –effective (under $400 for materials) preserving agents / refrigeration can be used to prolong shelf-life creation is simple and can be replicated by any other group methods can be modified to suit unique research areas is an appropriate method to validate segmentation methods

Acknowledgements Supervisors: Sources of Funding and Collaboration: Dr. Robert Bartha Dr. Michael Borrie Collaborators: John Drozd Robert Moreland Robert Ta Support: Kim Krueger Adam McLean Joe Gati Michael Marynowski Henry Betta Vaishali Karnik Sources of Funding and Collaboration: