Human Acute Cerebral Ischemia: Detection of Changes in Water Diffusion Anisotropy by Using MR Imaging

Sorensen, A. Gregory; Wu, Ona; Copen, W.A.; Davis, Timothy L.; González, R. Gilberto; Koroshetz, Walter J.; Reese, Timothy G.; Rosen, Bruce R.; Wedeen, Van J.; Weisskoff, Robert M.

doi:10.1148/radiology.212.3.r99se24785

Cited by 263 publications

(192 citation statements)

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“…6,7,21 DTI-based techniques, which are predicated on the quantification of the randomness of water molecule diffusion, are informative on the microstructural integrity of WM. 9,26,27 With respect to NAWM, several studies have used a DTI-based approach to emphasize that the detection of microstructural injury of NAWM precedes the genesis of overt WMH. 6,28 A recent study of patients with mild ischemic stroke demonstrated that MD was the most sensitive metric for distinguishing WMH from NAWM and that the accumulation of interstitial fluid is involved in WMH pathogenesis.…”

Section: Resultsmentioning

confidence: 99%

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Integrity of normal-appearing white matter and functional outcomes after acute ischemic stroke

Etherton

Cougo

et al. 2017

Neurology

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Objective: To characterize the effect of white matter microstructural integrity on cerebral tissue and long-term functional outcomes after acute ischemic stroke (AIS).Methods: Consecutive AIS patients with brain MRI acquired within 48 hours of symptom onset and 90-day modified Rankin Scale (mRS) score were included. Acute infarct volume on diffusion-weighted imaging (DWIv) and white matter hyperintensity volume (WMHv) on T2 fluidattenuated inversion recovery MRI were measured. Median fractional anisotropy (FA), mean diffusivity, radial diffusivity, and axial diffusivity values were calculated within normal-appearing white matter (NAWM) in the hemisphere contralateral to the acute lesion. Regression models were used to assess the association between diffusivity metrics and acute cerebral tissue and longterm functional outcomes in AIS. Level of significance was set at p , 0.05 for all analyses.Results: Among 305 AIS patients with DWIv and mRS score, mean age was 64.4 6 15.9 years, and 183 participants (60%) were male. Median NIH Stroke Scale (NIHSS) score was 3 (interquartile range [IQR] 1-8), and median normalized WMHv was 6.19 cm 3 (IQR 3.0-12.6 cm 3 ). Admission stroke severity (b 5 0.16, p , 0.0001) and small vessel stroke subtype (b 5 21.53, p , 0.0001), but not diffusivity metrics, were independently associated with DWIv. However, median FA in contralesional NAWM was independently associated with mRS score (b 5 29.74, p 5 0.02), along with age, female sex, NIHSS score, and DWIv.Conclusions: FA decrease in NAWM contralateral to the acute infarct is associated with worse mRS category at 90 days after stroke. These data suggest that white matter integrity may contribute to functional recovery after stroke. Neurology ® 2017;88:1701-1708 GLOSSARY AD 5 axial diffusivity; AIS 5 acute ischemic stroke; DTI 5 diffusion tensor imaging; DWIv 5 diffusion-weighted imaging volume; FA 5 fractional anisotropy; FLAIR 5 fluid-attenuated inversion recovery; IQR 5 interquartile range; MD 5 mean diffusivity; MNI 5 Montreal Neurological Institute; mRS 5 modified Rankin Scale; nDWIv 5 normalized diffusion-weighted imaging volume; NAWM 5 normal-appearing white matter; NIHSS 5 NIH Stroke Scale; nWMHv 5 normalized white matter hyperintensity volume; RD 5 radial diffusivity; TOAST 5 Trial of Org 10172 in Acute Stroke Treatment; tPA 5 tissue plasminogen activator; WM 5 white matter; WMH 5 white matter hyperintensity; WMHv 5 white matter hyperintensity volume.The role of white matter hyperintensity (WMH), or leukoaraiosis, in outcomes after acute ischemic stroke (AIS) is increasingly recognized through its link to larger acute infarct lesions, 1 likelihood of infarct expansion, 2 and association with worse functional poststroke outcomes. [3][4][5] However, a growing body of evidence suggests that macrostructural white matter (WM) disease burden, quantified as WMH on T2-weighted fluid-attenuated inversion recovery (FLAIR) MRI, may not adequately reflect the total extent of WM injury and that microstructural injury to normal-appear...

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confidence: 99%

“…DWI datasets were corrected for eddy current distortions and motion. 9 All DWI and FLAIR datasets were coregistered to one another with nonlinear coregistration techniques (Montreal Neurological Institute [MNI] Autoreg 10,11 ) and to the MNI 452 1-mm atlas. 12 WMH volumetric analysis.…”

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Integrity of normal-appearing white matter and functional outcomes after acute ischemic stroke

Etherton

Cougo

et al. 2017

Neurology

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“…Although both ADC¿ and ADC¥have been considered to decrease early in ischemia, 13,16,17,39,40 few have described ADC¿ and ADC¥immediately after ischemia. In feline global cerebral ischemia, Pierpaoli and colleagues 36 showed that ADC approximately perpendicular to the internal capsule declined 36z from its preischemic value after 22 min of ischemia.…”

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confidence: 99%

How Does Water Diffusion in Human White Matter Change Following Ischemic Stroke?

Tamura¹,

Kurihara

Machida³

et al. 2009

magn reson med sci

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Purpose: Temporal evolution of the water apparent diŠusion coe‹cients (ADC) parallel (ADC¿) and perpendicular (ADC¥) to the human white matter tract following ischemia has not been investigated systematically. We attempted to quantify the evolution of ADC¿ and ADC¥ and examine whether it can be interpreted by a model of ischemic edema.Methods: We retrospectively selected 53 patients with ischemic lesions involving the posterior limb of the internal capsule (PLIC) and placed regions of interest in the right and left PLIC on ADC maps. We performed regression analysis of lesion-to-contralateral ratios of ADC¿ and ADC¥against the time (t＝1-1600 h) from onset. We thenˆtted the estimated time courses of ADC¿ and ADC¥obtained from the analysis to a model of nerve tissue composed of cylinders (axons) and spheres corresponding to isotropic structures, particularly focal cytoplasmic swellings of glial cells and axons seen in ischemic white matter.Results: The evolution of ADC¥ and ADC¿ diŠered. The estimated time course of ADC¿ in mm 2 ･ms -1 was 0.64＋0.88 exp (-0.24t) for 1ºtº54 h and 0.00059t＋0.61 for tAE54 h (contralateral normal value, 1.52). That of ADC¥ was 0.19-0.063 exp (-0.24t) for 1ºtº54 h and 0.00040t＋0.17 for tAE54 h (normal value 0.22). The modelˆtted to these values showed that the volume of the cylinders decreased, that of the spheres increased, and extracellular volume changed little from one hour to approximately one day after stroke onset.Conclusion: In the human PLIC, ADC¿ continued to decrease from one hour to a few days after stroke onset, and ADC¥tended to increase. The temporal evolution could be interpreted by progression of the focal cytoplasmic swelling of glial cells and axons previously observed in animal studies.Keywords: cytotoxic edema, glia, intracellular space, vasogenic edema Introduction DiŠusion-weighted (DW) magnetic resonance (MR) imaging enables noninvasive measurement of the diŠusivity of water molecules in the human brain. Prompt reduction of the apparent diŠusion coe‹cient (ADC) in ischemic tissue causes hyperintensity on DW images, which aids detection of early changes in the brain after onset of ischemic stroke. [1][2][3] ADC measurement may also be useful in characterizing ischemic damage and selecting therapeutic procedure. 4 Many studies have demonstrated temporal evolution of the mean diŠusivity (, trace/3 of the diŠusion tensor) in patients with stroke. 5-13Follow-122 122 H. Tamura et al. Magnetic Resonance in Medical Sciencesing acute reduction of after the onset of cerebral ischemia, decreases slightly over 24 hours in many cases, [5][6][7][8][9] reaches a minimum, gradually increases to a normal value (pseudonormalization) between several days and one month, and continues to increase. Although the decrease is generally attributed to cellular edema and the increase to vasogenic edema and degradation of membrane structure, 1,[10][11][12] the exact mechanisms of these changes in remain unclear.Human and animal studies show a decline in diŠusion anisot...

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“…Diffusion-Weighted MR Imaging (DWI) derives contrast from regional differences in mobility of water molecules and has been related to cytotoxic edema and necrosis in brain tissues [1,2]. Diffusion co-efficients are not directly measured but are expressed as apparent diffusion co-efficients (ADC) in millimetres squared per second, measured on MR images.…”

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Change in diffusion weighted MRI during liver cancer radiotherapy: Preliminary observations

Eccles

Haider

et al. 2009

Acta Oncologica

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Human Acute Cerebral Ischemia: Detection of Changes in Water Diffusion Anisotropy by Using MR Imaging

Abstract: Gray matter is mildly anisotropic in normal and early ischemic states. However, early white matter ischemia is associated with not only changes in trace ADC values but also significant changes in the anisotropy, or shape, of the water self-diffusion tensor.

Cited by 263 publications

References 36 publications

Integrity of normal-appearing white matter and functional outcomes after acute ischemic stroke

Integrity of normal-appearing white matter and functional outcomes after acute ischemic stroke

How Does Water Diffusion in Human White Matter Change Following Ischemic Stroke?

Change in diffusion weighted MRI during liver cancer radiotherapy: Preliminary observations

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