Thomas Kwee1, Craig Galban1, Marko Ivancevic1,2, Pia Sundgren1, Christina Tsien3, Larry Junck4, Benjamin Hoff1, Charles Meyer1, Brian Ross1, Thomas Chenevert1
1Department of Radiology, University of Michigan, Ann Arbor, MI, USA; 2Philips Healthcare, Cleveland, OH, USA; 3Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; 4Department of Neurology, University of Michigan, Ann Arbor, MI, USA
Diffusion-weighted signal decay of brain tissue is multi-exponential due to the presence of multiple intravoxel proton pools (IPPs) with different diffusion coefficients. This study investigated the intravoxel water diffusion heterogeneity (IDWH) of human high-grade gliomas (N=20), using the stretched-exponential model. IDWH was significantly higher in high-grade gliomas than in normal brain tissue, which potentially offers a new method for assessing tumor extent and evaluating therapeutic response. Correlation between tumor IDWH and overall tumor diffusion coefficient was strongly negative, suggesting that highly cellular tumors contain a lower number of distinct IPPs, while cystic/necrotic tumors contain a higher number of distinct IPPs.