"Squashing peanuts and smashing pumpkins": how noise distorts diffusion-weighted MR data. Export

@article{citeulike:3196218, abstract = {New diffusion-weighted imaging (DWI) methods, including high-b, q-space, and high angular resolution MRI methods, attempt to extract information about non-Gaussian diffusion in tissue that is not provided by low-b-value (b approximately 1000 s mm(-2)) diffusion or diffusion tensor magnetic resonance imaging (DT-MRI). Additionally, DWI data with higher spatial resolution are being acquired to resolve fine anatomic structures, such as white matter fasciculi. Increasing diffusion-weighting or decreasing voxel size can reduce the signal-to-noise ratio so that some DWI signals are close to the background noise level. Here we report several new artifacts that can be explained by considering how background noise affects the peanut-shaped angular apparent diffusion coefficient (ADC) profile. These include an orientationally dependent deviation from Gaussian behavior of the ADC profile, an underestimation of indices of diffusion anisotropy, and a correlation between estimates of mean diffusivity and diffusion anisotropy. We also discuss how noise can cause increased gray/white matter DWI contrast at higher b values and an apparent elevation of diffusion anisotropy in acute ischemia. Importantly, all of these artifacts are negligible in the b-value range typically used in DT-MRI of brain (b approximately 1000 s mm(-2)). Finally, we demonstrate a strategy for ameliorating the rectified noise artifact in data collected at higher b values.}, address = {Section on Tissue Biophysics and Biomimetics, Laboratory of Integrative Medicine and Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-5772, USA. jonesde@mail.nih.gov}, author = {Jones, D. K. and Basser, P. J.}, citeulike-article-id = {3196218}, citeulike-linkout-0 = {http://dx.doi.org/10.1002/mrm.20283}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/15508154}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=15508154}, doi = {10.1002/mrm.20283}, issn = {0740-3194}, journal = {Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine}, keywords = {artifacts, dwi, effects, jones\_dk, noise, of}, month = {November}, number = {5}, pages = {979--993}, posted-at = {2009-06-30 21:05:37}, priority = {2}, title = {"Squashing peanuts and smashing pumpkins": how noise distorts diffusion-weighted MR data.}, url = {http://dx.doi.org/10.1002/mrm.20283}, volume = {52}, year = {2004} }

TY - JOUR ID - citeulike:3196218 L3 - citeulike-article-id:3196218 N2 - New diffusion-weighted imaging (DWI) methods, including high-b, q-space, and high angular resolution MRI methods, attempt to extract information about non-Gaussian diffusion in tissue that is not provided by low-b-value (b approximately 1000 s mm(-2)) diffusion or diffusion tensor magnetic resonance imaging (DT-MRI). Additionally, DWI data with higher spatial resolution are being acquired to resolve fine anatomic structures, such as white matter fasciculi. Increasing diffusion-weighting or decreasing voxel size can reduce the signal-to-noise ratio so that some DWI signals are close to the background noise level. Here we report several new artifacts that can be explained by considering how background noise affects the peanut-shaped angular apparent diffusion coefficient (ADC) profile. These include an orientationally dependent deviation from Gaussian behavior of the ADC profile, an underestimation of indices of diffusion anisotropy, and a correlation between estimates of mean diffusivity and diffusion anisotropy. We also discuss how noise can cause increased gray/white matter DWI contrast at higher b values and an apparent elevation of diffusion anisotropy in acute ischemia. Importantly, all of these artifacts are negligible in the b-value range typically used in DT-MRI of brain (b approximately 1000 s mm(-2)). Finally, we demonstrate a strategy for ameliorating the rectified noise artifact in data collected at higher b values. IS - 5 JF - Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine SN - 0740-3194 AD - Section on Tissue Biophysics and Biomimetics, Laboratory of Integrative Medicine and Biophysics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-5772, USA. jonesde@mail.nih.gov EP - 993 TI - "Squashing peanuts and smashing pumpkins": how noise distorts diffusion-weighted MR data. VL - 52 SP - 979 KW - artifacts KW - dwi KW - effects KW - jones_dk KW - noise KW - of AU - Jones, DK AU - Basser, PJ PY - 2004/11// UR - http://dx.doi.org/10.1002/mrm.20283 ER -