Multiparametric MRI Tissue Characterization in Clinical Stroke With Correlation to Clinical Outcome

Jacobs, Michael A.; Mitsias, Panayiotis; Soltanian‐Zadeh, Hamid; Santhakumar, Sunitha; Ghanei, Amir; Hammond, Rabih; Peck, Donald J.; Chopp, Michael; Patel, Suresh

doi:10.1161/01.str.32.4.950

Cited by 81 publications

(87 citation statements)

References 33 publications

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“…Many tissue signature models that involve conventional DWI acquisition methods have been reported. These models relate DWI signal intensity or ADC to the development of infarction or hemorrhagic transformation in stroke (12,26,(32)(33)(34)(35)(36)(37)(38). A systematic change in the ADC of 15% related to CSF partial volume effects would be likely to change the sensitivity of these models and the reliability of threshold values that distinguish viable from nonviable tissue.…”

Section: Discussionmentioning

confidence: 99%

Cerebral spinal fluid contamination of the measurement of the apparent diffusion coefficient of water in acute stroke

Latour

Warach

2002

Magnetic Resonance in Med

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Section: Discussionmentioning

confidence: 99%

Cerebral spinal fluid contamination of the measurement of the apparent diffusion coefficient of water in acute stroke

Latour

Warach

2002

Magnetic Resonance in Med

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“…This approach requires the number of tissue clusters to be assigned a priori, which is generally unknown during the evolution of cerebral ischemia. Jacobs et al (2001a) and Mitsias et al (2002) eloquently incorporated the iterative self-organizing data analysis algorithm (ISODATA) (Ball and Hall, 1965) for analyzing T 1 -, T 2 -and diffusion-weighted images in human stroke and found that the multiparametric ISODATA analysis outperformed analysis using any single parameter alone. This approach has also been applied to analyze T 1 -, T 2 -and diffusion-weighted images in an animal stroke models during the subacute and chronic phase (Jacobs et al, 2001b).…”

Section: Introductionmentioning

confidence: 99%

Statistical Prediction of Tissue Fate in Acute Ischemic Brain Injury

Shen

Ren

Fisher

et al. 2005

J Cereb Blood Flow Metab

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An algorithm was developed to statistically predict ischemic tissue fate on a pixel-by-pixel basis. Quantitative high-resolution (200 Â 200 lm) cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were measured on acute stroke rats subjected to permanent middle cerebral artery occlusion and an automated clustering (ISODATA) technique was used to classify ischemic tissue types. Probability and probability density profiles were derived from a training data set (n ¼ 6) and probability maps of risk of subsequent infarction were computed in another group of animals (n ¼ 6) as ischemia progressed. Predictions were applied to overall tissue fate. Performance measures (sensitivity, specificity, and receiver operating characteristic) showed that prediction made based on combined ADC þ CBF data outperformed those based on ADC or CBF data alone. At the optimal operating points, combined ADC þ CBF predicted tissue infarction with 86%74% sensitivity and 89%76% specificity. More importantly, probability of infarct (P I ) for different ISODATA-derived ischemic tissue types were also computed: (1) For the 'normal' cluster in the ischemic right hemisphere, P I based on combined ADC þ CBF data (P I [ADC þ CBF]) accurately reflected tissue fate, whereas P I [ADC] and P I [CBF] overestimated infarct probability. (2) For the 'perfusion-diffusion mismatch' cluster, P I [ADC þ CBF] accurately predicted tissue fate, whereas P I [ADC] underestimated and P I [CBF] overestimated infarct probability. (3) For the core cluster, P I [ADC þ CBF], P I [ADC], and P I [CBF] prediction were high and similar (B90%). This study shows an algorithm to statistically predict overall, normal, ischemic core, and 'penumbral' tissue fate using early quantitative perfusion and diffusion information. It is suggested that this approach can be applied to stroke patients in a computationally inexpensive manner.

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“…T2-relaxation values increase with increased free tissue water content (9), in the absence of diamagnetic and paramagnetic substances; values decrease in those sites with hemosiderin deposition (12). Increased free water content typically reflects cellular and axonal loss or membrane breakdown, with such breakdown accompanying cellular and myelin changes with age (6,7) and certain pathological processes.T2-relaxometry has been used successfully to evaluate age-related neuronal and axonal changes in pediatric and adult subjects (13,14), and to detect tissue abnormalities in multiple central nervous systemrelated medical conditions (6,7,(15)(16)(17)(18). However, only a few reports are available for T2-relaxometry procedures from adult subjects, with samples from limited brain sites; overall brain evaluation is lacking.…”

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confidence: 99%

Age‐related regional brain T2‐relaxation changes in healthy adults

Kumar

Delshad

Woo

et al. 2011

Magnetic Resonance Imaging

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Purpose: To determine normal T2-relaxation values from different brain areas in healthy adults, assess age-related T2-relaxation changes in those sites, and evaluate potential gender-related T2-relaxation value differences. Materials and Methods:We performed proton-density and T2-weighted imaging in 60 healthy adults (male: 38, age range ¼ 31-64 years, mean age 6 SD ¼ 46.1 6 9.3 years; female: 22, age range ¼ 37-66 years, mean age 6 SD ¼ 49.5 6 8.3 years), using a 3.0 Tesla MRI scanner. T2-relaxation values were calculated voxel-by-voxel from proton-density and T2-weighted images, and whole-brain T2-relaxation maps were constructed and normalized to a common space. A set of regions-of-interest were outlined within the basal ganglia, limbic, frontal, parietal, temporal, occipital, thalamic, hypothalamic, cerebellar, and pontine regions using mean background images derived from normalized and averaged T2-weighted images of all individuals, and regional T2-relaxation values were determined from these regions-of-interest and normalized T2-relaxation maps. Pearson's correlations were calculated between T2-relaxation values and age, and male-female differences evaluated with independent-samples t-tests.Results: T2-relaxation values typically increased with age in multiple brain sites; only a few regions showed declines, including the putamen and ventral pons. Sexrelated differences in T2-relaxation values appeared in basal ganglia, frontal, temporal, occipital, and cerebellar regions; males showed higher values over females in these sites.Conclusion: Establishment of normative adult T2-relaxation values over different brain areas, with age and sex as co-factors, offers baseline values against which diseaserelated tissue changes can be assessed. NONINVASIVE ASSESSMENT OF adult human brain changes resulting from neurologic, neuropsychological, and neurocognitive pathologies against normal age-related changes remains difficult (1-3). Myelin and neurons undergo slow degradation with age in adults (4,5), and these normative changes, as well as neurodegenerative processes inducing myelin and neuronal loss (6,7), increase free tissue water content. However, certain deep brain structures, including the basal ganglia, are known to show iron deposition with age in adult subjects (8), which can alter indications of normal progression of tissue changes in these sites. Pathological and treatment-related brain tissue alterations can be assessed accurately, but only after controlling for age-related changes, which mandates determination of normative values from gray and white matter regions over wide-spread brain areas.MR T2-relaxometry provides a quantitative surrogate marker of brain tissue changes in both health and disease by assessing free tissue water content (9) in the absence of diamagnetic and paramagnetic substances, which differs during pediatric development over normal patterns of aging in adult controls (5,10), and increases with disease processes (11). T2-relaxation values increase with increased free tissue water cont...

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Multiparametric MRI Tissue Characterization in Clinical Stroke With Correlation to Clinical Outcome

Cited by 81 publications

References 33 publications

Cerebral spinal fluid contamination of the measurement of the apparent diffusion coefficient of water in acute stroke

Cerebral spinal fluid contamination of the measurement of the apparent diffusion coefficient of water in acute stroke

Statistical Prediction of Tissue Fate in Acute Ischemic Brain Injury

Age‐related regional brain T2‐relaxation changes in healthy adults

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