Gary E. Christensen

gary-christensen@uiowa.edu

Associate Professor of Electrical and Computer Engineering,
The Robert and Virginia Wheeler Faculty Fellow of Engineering
College of Engineering, The University of Iowa

Research Projects Ongoing or Completed During the Last 3 Years:

"Modeling Cranial Dysmorphology and Its Correction Using Pattern Theory"
Principal Investigator: Gary E. Christensen, D.Sc.
Agency: The Whitaker Foundation
Type: Research Grant
Period: December 1995 - January 1997, August 1997 - January 2000.
The major goals of this project are to develop methods for measuring normal and dysmorphic infant skull shape and interval shape change (due to surgical intervention and growth) as observed by CT using a deformable atlas. The specific aims of this project are: (1) construct a volumetric deformable atlas of a normal infant head from CT data; (2) develop new tools for measuring and visualizing skull shape and interval skull shape change; (3) test and validate the new measurement tools using CT data sets with known measurements and simulated deformities; (4) measure and visualize areas of abnormal shape of dysmorphic infant skulls observed by CT; and (5) evaluate outcome of surgical interventions by comparing measures of calvarial shape as observed by CT before and after surgery.

"ATM Distributed Medical Imaging"
Principal Investigator: Gary E. Christensen, D.Sc.
Agency: Washington University/NSF
Type: Equipment Grant
Period: November 1998 - November 1999.
The long term goal of this project is to create a real-time environment in which computer processing, visualization, and data archiving are independent of the physical location between distributed laboratories in the College of Engineering and the Medical School at The University of Iowa.

"Normal MR Neuromorphometry by Global Pattern Matching"
Co-Investigator: Gary E. Christensen
Agency: NIH/NINDS
Type: R01 NS35368-01
Period: May 1996 - February 2001.
The major focus of this project is the development of mathematical representations of neuroanatomical variation of the brain and specific subregions, especially in the hippocampus and temporal lobe. The specific aims of this project are: (1) to synthesize a labeled multimodality volumetric brain atlas; (2) to determine precision and repeatability of the global pattern matching (GPM) method and MR scanning for brain structural volume measurement in normal control subjects; (3) to measure brain structure variability in a normal population; (4) to validate the method in vitro and in vivo; and (5) to apply the GPM method to subgroups, separating the effects of gender, laterality and handiness. The PI on this grant is Dr. Michael W. Vannier, Professor and Chairman of Radiology, The University of Iowa, Iowa City, Iowa.

"Image-Based Dose Planning in Intracavitary Brachytherapy"
Co-Investigator: Gary E. Christensen
Agency: NIH
Type: R01 CA75731,
Period: May 1998 - February 2002
The major goal of this project is to exploit MR and CT volumetric imaging for evaluation and planning of pelvic brachytherapy treatments delivered as multiple insertions and/or in combination with external-beam therapy. The specific aims of this project are: (1) develop a novel method for obtaining high-quality 3D spiral CT images in the presence of metal intracavitary applicators and sources; (2) develop methods for registration of normal pelvic soft tissue anatomy and primary cervical tumor visualized by CT and MR with and without intracavitary applicators in place; and (3) perform clinical studies to validate the algorithms, evaluate clinical and dosimetric significance, characterize the target volume and critical structure dose distributions, and design larger scale clinical studies for measuring normal-tissue and tumor dose-response relationships. The PI on this grant is Dr. Jeffrey F. Williamson, Ph.D., Professor of Radiology, Washington University School of Medicine, St. Louis, MO.

"Spiral CT for Cochlear Implantation Research Plan"
Co-Investigator: Gary E. Christensen
Agency: NIH
Type: R01 DC03590,
Period: May 1999 - April 2004
The long term goal of this project is to define implanted cochlear morphology and improve speech recognition using this 3D geometric information. The specific aims of this grant are: (1) to localize implant electrodes in 3D with post-operative X-ray stereophotogrammetry, and incorporate this information in corresponding spiral CT images; (2) deblur and unwrap the cochlea in volumetric spiral CT images pre- and post-operatively; (3) develop and validate geometric models of individual implanted cochleas, and demonstrate their clinical feasibility and utility in patient studies. The PI on this grant is Dr. Ge Wang, Ph.D., Associate Professor of Radiology, The University of Iowa, Iowa City, Iowa.