Sean Foxley BS, Presenter: Nothing to Disclose

Devkumar Mustafi PhD, Abstract Co-Author: Nothing to Disclose

Cheng Yang PhD, Abstract Co-Author: Nothing to Disclose

Xiaobing Fan PhD, Abstract Co-Author: Nothing to Disclose

Milica Medved PhD, Abstract Co-Author: Nothing to Disclose

Marta A Zamora BS, Abstract Co-Author: Nothing to Disclose

Gregory Stanislaus Karczmar PhD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Work in this lab has demonstrated the use of echo-planar spectroscopic imaging (EPSI) for acquisition of high spectral and spatial resolution (HiSS) data to produce improved anatomical and functional images. A water spectrum is generated for each image voxel, the details of which are analyzed for image generation. Most work has focused on analysis of the water’s peak height and line width. But the tumor’s subvoxelar environment contains varying magnetic susceptibilities, producing different components of the water resonance. This can result in inhomogeneous broadening of the water line. Collecting HiSS data enables us to observe such spectral inhomogeneities and utilize them to obtain previously unavailable information.

Copenhagen rats bearing metastatic rat prostate AT6.1 tumors inoculated in the hind leg were used (n=5). Images were acquired pre and post I.V. injection of blood pool contrast agents at 4.7T. Fourier component images (FCIs) were produced with intensities proportional to the amplitude of the off-peak components of the water resonance. In addition, the asymmetry of the water line was measured in each voxel.

FCI’s showed features in tumors that were not visible in water peak height images. Spectral water lines in tumor voxels displayed greater asymmetry than those of the normal tissue, suggesting greater spectral inhomogeneity. Water lineshapes in tumor voxels, and the spatial distribution of water spectrum asymmetry in the tumor were significantly changed following the injection of contrast agents. Images of changes in water resonance asymmetry and images of changes in water peak height following contrast injection showed different anatomic features.

The data demonstrate that FCIs provide morphological information in tumors that is not available in conventional or water peak height images. Changes following contrast media injection suggest that the off-peak FCIs’ represent regions of subvoxelar tumor vasculature. This information would be extremely useful in the clinical setting both for cancer diagnosis and for guiding therapy.

Work in this lab has demonstrated the use of echo-planar spectroscopic imaging (EPSI) for acquisition of high spectral and spatial resolution (HiSS) data to produce improved anatomical and functional images. A water spectrum is generated for each image voxel, the details of which are analyzed for image generation. Most work has focused on analysis of the water’s peak height and line width. But the tumor’s subvoxelar environment contains varying magnetic susceptibilities, producing different components of the water resonance. This can result in inhomogeneous broadening of the water line. Collecting HiSS data enables us to observe such spectral inhomogeneities and utilize them to obtain previously unavailable information.

Copenhagen rats bearing metastatic rat prostate AT6.1 tumors inoculated in the hind leg were used (n=5). Images were acquired pre and post I.V. injection of blood pool contrast agents at 4.7T. Fourier component images (FCIs) were produced with intensities proportional to the amplitude of the off-peak components of the water resonance. In addition, the asymmetry of the water line was measured in each voxel.

FCI’s showed features in tumors that were not visible in water peak height images. Spectral water lines in tumor voxels displayed greater asymmetry than those of the normal tissue, suggesting greater spectral inhomogeneity. Water lineshapes in tumor voxels, and the spatial distribution of water spectrum asymmetry in the tumor were significantly changed following the injection of contrast agents. Images of changes in water resonance asymmetry and images of changes in water peak height following contrast injection showed different anatomic features.

The data demonstrate that FCIs provide morphological information in tumors that is not available in conventional or water peak height images. Changes following contrast media injection suggest that the off-peak FCIs’ represent regions of subvoxelar tumor vasculature. This information would be extremely useful in the clinical setting both for cancer diagnosis and for guiding therapy.

Foxley, S, Mustafi, D, Yang, C, Fan, X, Medved, M, Zamora, M, Karczmar, G, et al, , Fourier Component MRI of Tumors Provides New Anatomical and Functional Information.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4410157.html