title: Pore diameter mapping using double pulsed-field gradient MRI and its validation using a novel glass capillary array phantom.
abstract: Double pulsed-field gradient (d-PFG) MRI can provide quantitative maps of microstructural quantities and features within porous media and tissues. We propose and describe a novel MRI phantom, consisting of wafers of highly ordered glass capillary arrays (GCA), and its use to validate and calibrate a d-PFG MRI method to measure and map the local pore diameter. Specifically, we employ d-PFG Spin-Echo Filtered MRI in conjunction with a recently introduced theoretical framework, to estimate a mean pore diameter in each voxel within the imaging volume. This simulation scheme accounts for all diffusion and imaging gradients within the diffusion weighted MRI (DWI) sequence, and admits the violation of the short gradient pulse approximation. These diameter maps agree well with pore sizes measured using both optical microscopy and single PFG diffusion diffraction NMR spectroscopy using the same phantom. Pixel-by-pixel analysis shows that the local pore diameter can be mapped precisely and accurately within a specimen using d-PFG MRI.
authors.affiliation: Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Sciences, NICHD, NIH, Bethesda, MD 20892-5772, USA. komloshm@mail.nih.gov
authors.forename: Michal E
authors.initials: ME
authors.lastname: Komlosh
authors.forename: Evren
authors.initials: E
authors.lastname: Özarslan
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Lizak
authors.forename: Ferenc
authors.initials: F
authors.lastname: Horkay
authors.forename: Vincent
authors.initials: V
authors.lastname: Schram
authors.forename: Noam
authors.initials: N
authors.lastname: Shemesh
authors.forename: Yoram
authors.initials: Y
authors.lastname: Cohen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Basser
mesh_terms: D002197:Capillary Action; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000032:analysis / Q000737:chemistry*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods; D019047:Phantoms, Imaging; D016062:Porosity