Title

Partial-volume effect on ischemic tissue-fate delineation using quantitative perfusion and diffusion imaging on a rat stroke model

UMMS Affiliation

Department of Neurology

Publication Date

2004-11-25

Document Type

Article

Subjects

Animals; Brain Ischemia; Cerebrovascular Circulation; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Image Processing, Computer-Assisted; Male; Rats; Rats, Sprague-Dawley; Stroke

Disciplines

Nervous System Diseases | Neurology

Abstract

Partial-volume effects (PVE) in stroke imaging could hinder proper delineation of normal, ischemic, and at-risk tissues. Cerebral-blood-flow (CBF) and apparent diffusion coefficient (ADC) were measured at high and low resolution (HR = 128 x 128, LR = 64 x 64) in focal ischemia in rats during the acute phase. The data were evaluated for PVE on ischemic tissue classification on a pixel-by-pixel basis and the misclassified pixels were quantified as ischemia progressed. The main drawbacks of high-resolution imaging are reduced temporal resolution and/or signal-to-noise ratio. The high- versus low-resolution scatterplots and histograms of pixels along the normal-abnormal boundaries in the ADC and CBF maps showed marked ischemia-related PVE. By comparison with the homologous regions in the contralateral normal hemisphere, the effect of increased noise and intrinsic tissue heterogeneity due to high resolution could be distinguished from ischemia-related PVE. Degrading the high-resolution (128 x 128) data to a 64 x 64 or 32 x 32 matrix increased the severity of PVE. Zero-filling of low-resolution (64 x 64) data to 128 x 128 also increased PVE. It was concluded that PVE: (1) misclassified substantial pixels along the normal-abnormal boundaries, (2) overestimated abnormal volumes at the expense of mostly "at-risk" and some "normal" tissues, (3) were more severe at the early time points postischemia, and (4) confounded the interpretation of the operationally defined ischemic penumbra.

DOI of Published Version

10.1002/mrm.20299

Source

Magn Reson Med. 2004 Dec;52(6):1328-35. Link to article on publisher's site

Journal/Book/Conference Title

Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine

Related Resources

Link to article in PubMed

PubMed ID

15562470

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