The temporal evolution of MRI tissue signatures after transient middle cerebral artery occlusion in rat

Jiang, Quan; Chopp, Michael; Zhang, Zheng G.; Knight, Robert A.; Jacobs, Michael A.; Windham, J.P.; Peck, Donald J.; Ewing, James R.; Welch, Keasley

doi:10.1016/s0022-510x(96)00286-9

Cited by 87 publications

(84 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following reductions in the acute phase, <D> values renormalize several days after stroke onset and then increase in the ensuing days and weeks. [20][21][22] These changes coincide with the development of vasogenic edema and are well correlated with increases in tissue water content (as measured by M o ) and the T 2 relaxation time.…”

Section: Water Diffusion Changes In Experimental Cerebral Ischemiamentioning

confidence: 74%

“…55 Given the potential pitfalls associated with using the ADC alone as a predictor of ischemic injury, a number of investigators have attempted to combine the ADC information with that of other MR parameters to unambiguously stage and predict ischemic brain injury over its entire temporal evolution. 18,22,28,[56][57][58][59][60][61][62][63][64][65] Although DTI has not been employed as a parameter in many of these investigations, more recent studies have begun to examine the role of DTI (and in particular indices of diffusion anisotropy) as a potential marker to predict stroke outcome. 18,31,32,43,65 For example, Yang et al found differences in the ischemic time course of ADC and diffusion anisotropy between patients and within individual lesions.…”

Section: The Role Of Water Diffusion Changes In the Prediction Of Iscmentioning

confidence: 99%

See 1 more Smart Citation

The role of diffusion tensor imaging in the evaluation of ischemic brain injury – a review

2002

View full text Add to dashboard Cite

Water diffusion in brain tissue is affected by the presence of barriers to translational motion such as cell membranes and myelin fibers. The measured water apparent diffusion coefficient (ADC) value is therefore frequently anisotropic and varies depending upon the orientation of restricting barriers (such as white matter tracts) relative to the diffusion-sensitive-gradient direction. Anisotropic water diffusion can be specified using indices of diffusion anisotropy [e.g. standard deviation of the individual ADC values, fractional anisotropy (FA), lattice index (LI)], which are derived from measurements of the full diffusion tensor. The rotationally invariant nature of particular diffusion anisotropy indices (e.g. FA, LI) allows orientation-independent comparisons of these parameters between different subjects. Pathophysiological processes (such as cerebral ischemia) that modify the integrity of the tissue microstructure result in significant alterations in tissue anisotropy and make this metric a useful endpoint for characterizing the temporal evolution of the disease. Diffusion-tensor imaging (DTI) studies of both experimental and human stroke suggest that DTI may provide additional information about the evolution of the disease that is not available from diffusion-weighted MRI (DWI) alone. Acute reductions in the average diffusivity [ = ( 1 2 3 )/3 where 1 , 2 , and 3 are the eigenvalues of the diffusion tensor] following the onset of cerebral ischemia are often accompanied by increases in diffusion anisotropy. In the transition from acute to sub-acute and chronic stroke, renormalizes and subsequently increases whereas diffusion anisotropy measures (e.g. FA) decline and remained reduced in chronic infarcts. Overall isotropic ADC changes during infarct evolution have been observed to be greater in white matter (WM) than in gray matter (GM) lesions (although there have been conflicting reports on this issue) and GM lesions tend to renormalize prior to WM lesions as the infarct evolves. Ischemic WM exhibits a significant decrease in diffusion anisotropy (relative to normal WM) during ischemic evolution whereas that of ischemic GM remains statistically unchanged. Furthermore, the percentage decrease in ischemic WM is largely determined by reductions in 1 , the eigenvalue that coincides with the long axis of the WM fiber tract. Variations in unidirectional ADC or over the ischemic time course limit the usefulness of this parameter alone as a predictor of ischemic injury. Consequently, ADC information has been combined with that of other MR parameters (including DTI) to unambiguously stage and predict ischemic brain injury over its entire temporal evolution. Combined and diffusion anisotropy measurements have identified three phases of diffusion abnormality: (1) reduced and elevated anisotropy; (2) reduced and reduced anisotropy; and (3) elevated and reduced anisotropy. However, variations in the differential patterns of and diffusion anisotropy evolution have been obser...

show abstract

Section: Water Diffusion Changes In Experimental Cerebral Ischemiamentioning

confidence: 74%

Section: The Role Of Water Diffusion Changes In the Prediction Of Iscmentioning

confidence: 99%

The role of diffusion tensor imaging in the evaluation of ischemic brain injury – a review

2002

View full text Add to dashboard Cite

show abstract

“…Looking beyond this time point clearly reveals dramatic changes in both the size of the hyperintense T 2 region and a more heterogeneous pattern of T 2 values within the lesioned area ( Figure 5). One study suggested that different combinations of MRI signatures should be used to provide more information about histopathology, e.g., compromised tissue might have a low ADC but normal T 2 , and the T 2 value will increase as the tissue becomes more necrotic (Jiang et al, 1997).…”

Section: Magnetic Resonance Imagingmentioning

confidence: 99%

Visualizing Cell Death in Experimental Focal Cerebral Ischemia: Promises, Problems, and Perspectives

Zille

Farr

Przesdzing

et al. 2011

J Cereb Blood Flow Metab

124

View full text Add to dashboard Cite

One of the hallmarks of stroke pathophysiology is the widespread death of many different types of brain cells. As our understanding of the complex disease that is stroke has grown, it is now generally accepted that various different mechanisms can result in cell damage and eventual death. A plethora of techniques is available to identify various pathological features of cell death in stroke; each has its own drawbacks and pitfalls, and most are unable to distinguish between different types of cell death, which partially explains the widespread misuse of many terms. The purpose of this review is to summarize the standard histopathological and immunohistochemical techniques used to identify various pathological features of stroke. We then discuss how these methods should be properly interpreted on the basis of what they are showing, as well as advantages and disadvantages that require consideration. As there is much interest in the visualization of stroke using noninvasive imaging strategies, we also specifically discuss how these techniques can be interpreted within the context of cell death.

show abstract

“…To balance off-resonance magnetization transfer (MT) effects, images are usually acquired in sets of four, with both CW frequency offset and inversion gradient sign permuted through all four combinations (22). Four sets of four images (16 total) (23,24) are taken over a period of approximately 17 min. Weak diffusion gradients are employed (b Ϸ 10 s/mm 2 ) to kill signal from the large vessels.…”

Section: Experimental Paradigm: Steady-state Ast With Spin-echo Readoutmentioning

confidence: 99%

Single‐coil arterial spin‐tagging for estimating cerebral blood flow as viewed from the capillary: Relative contributions of intra‐ and extravascular signal

Ewing

Cao

Fenstermacher

2001

Magnetic Resonance in Med

View full text Add to dashboard Cite

The single-capillary model was applied to the exchange microvessels for water in the cerebral parenchyma and used to calculate blood-to-brain flux of water; the theory of the steadystate arterial spin-tagging (AST) technique for estimating cerebral blood flow (CBF) was revised to incorporate the presence of both extravascular (tissue) and capillary signal. A crucial element of the single-coil AST experiment is that magnetization transfer (MT) shortens the effective T 1 of the extravascular water, making it one-quarter that of the T 1 of capillary blood.

show abstract

The temporal evolution of MRI tissue signatures after transient middle cerebral artery occlusion in rat

Cited by 87 publications

References 34 publications

The role of diffusion tensor imaging in the evaluation of ischemic brain injury – a review

The role of diffusion tensor imaging in the evaluation of ischemic brain injury – a review

Visualizing Cell Death in Experimental Focal Cerebral Ischemia: Promises, Problems, and Perspectives

Single‐coil arterial spin‐tagging for estimating cerebral blood flow as viewed from the capillary: Relative contributions of intra‐ and extravascular signal

Contact Info

Product

Resources

About