Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice

Med Phys. 2006 Mar;33(3):753-60. doi: 10.1118/1.2163831.

Abstract

We are investigating imaging techniques to study the tumor response to photodynamic therapy (PDT). Positron emission tomography (PET) can provide physiological and functional information. High-resolution magnetic resonance imaging (MRI) can provide anatomical and morphological changes. Image registration can combine MRI and PET images for improved tumor monitoring. In this study, we acquired high-resolution MRI and microPET 18F-fluorodeoxyglucose (FDG) images from C3H mice with RIF-1 tumors that were treated with Pc 4-based PDT. We developed two registration methods for this application. For registration of the whole mouse body, we used an automatic three-dimensional, normalized mutual information algorithm. For tumor registration, we developed a finite element model (FEM)-based deformable registration scheme. To assess the quality of whole body registration, we performed slice-by-slice review of both image volumes; manually segmented feature organs, such as the left and right kidneys and the bladder, in each slice; and computed the distance between corresponding centroids. Over 40 volume registration experiments were performed with MRI and microPET images. The distance between corresponding centroids of organs was 1.5 +/- 0.4 mm which is about 2 pixels of microPET images. The mean volume overlap ratios for tumors were 94.7% and 86.3% for the deformable and rigid registration methods, respectively. Registration of high-resolution MRI and microPET images combines anatomical and functional information of the tumors and provides a useful tool for evaluating photodynamic therapy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Automation
  • Disease Models, Animal
  • Fluorodeoxyglucose F18
  • Image Processing, Computer-Assisted / methods*
  • Imaging, Three-Dimensional
  • Kidney / diagnostic imaging
  • Kidney / pathology
  • Magnetic Resonance Imaging / methods*
  • Mice
  • Neoplasms / diagnosis
  • Neoplasms / diagnostic imaging*
  • Neoplasms / pathology
  • Photochemotherapy / methods*
  • Positron-Emission Tomography / methods*
  • Radiography
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Time Factors
  • Urinary Bladder / diagnostic imaging
  • Urinary Bladder / pathology
  • Whole-Body Counting / veterinary

Substances

  • Fluorodeoxyglucose F18