Volumetric q-space imaging by 3D diffusion-weighted MRI.
High b-value diffusion magnetic resonance imaging (MRI) enables us to detect far smaller architectures, by using q-space analysis, than the resolution in conventional MRI. Average displacement, one of the q-space parameters, quantitatively reflects architecture size and is very useful in observing small changes in microstructures in vivo (e.g., neurodegeneration, tumor heterogeneity, and others). Diffusion-weighted imaging (DWI) is performed by a two-dimensional (2D) multislice method; however, due to finite slice thickness and slice gap, there is a partial-volume effect that makes it difficult to detect the net q-space signal. On the other hand, three-dimensional (3D) MRI, having the advantages of very thin slice thickness and no slice gap (contiguous slices), allows volumetric evaluation acquired in a small isotropic voxel, as compared to 2D multislice imaging. Little is known about the isotropic high-resolution 3D DWI application to q-space analysis. In this study, we have developed and implemented a high b-value 3D DWI sequence, applied q-space analysis to study the reliability of high b-value 3D DWI and obtained a microscopic analytical map with isotropic high resolution and less contamination.
Hikishima
Keigo
K
Biomedical Sensing and Imaging Group, National Institute of Advanced Industrial, Science and Technology (AIST), AIST Tsukuba East, Tsukuba 305-8564, Ibaraki, Japan. k-hikishima@ciea.or.jp
Yagi
Kazuo
K
Numano
Tomokazu
T
Homma
Kazuhiro
K
Nitta
Naotaka
N
Nakatani
Tetsu
T
Hyodo
Koji
K
D000465:Algorithms; D000818:Animals; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D005260:Female; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D015233:Models, Statistical; D019047:Phantoms, Imaging; D011336:Probability; D051381:Rats