Age dependency of the regional cerebral blood volume (rCBV) measured with dynamic susceptibility contrast MR imaging (DSC)

Wenz, Frederik; Rempp, Katrin; Brix, Gunnar; Knopp, Michael V.; Gückel, F.; Heß, Thomas; Kaick, G. van

doi:10.1016/0730-725x(95)02058-2

Cited by 51 publications

(33 citation statements)

References 15 publications

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“…These predictions are based on a significant body of literature demonstrating that these parameters vary with differing tissue concentrations of vasculature and myelin. More specifically: The T1 of blood is high whereas that of myelin is low, compared to average T1 in gray matter (Stanisz et al, 2005; Wansapura et al, 1999), thus an increase in T1 would be consistent with an increase in vasculature, while a decrease would be consistent with a shift toward myelin.T2 is similarly significantly higher in vasculature than in myelin-rich regions (Stanisz et al, 2005; Wansapura et al, 1999), thus a similar prediction applies.CBV is a direct measure of blood volume (Wenz et al, 1996; Lu et al, 2005; Barbier et al, 2001), thus it would obviously increase if vasculature increased, but a myelin change would not be predicted to change CBV.SWI images show lower intensity in highly vascularized regions (Haacke et al, 2004), thus an decrease in SWI would support an increase in vasculature. SWI signal in myelinated regions depends on a number of factors, such as the orientation of the fibers with respect to the field (Deistung et al, 2013; Lutti et al, 2013; Lee et al, 2012), thus no clear prediction with respect to myelin change can be made.…”

Section: Resultsmentioning

confidence: 86%

Multi-modal characterization of rapid anterior hippocampal volume increase associated with aerobic exercise

et al. 2016

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The hippocampus has been shown to demonstrate a remarkable degree of plasticity in response to a variety of tasks and experiences. For example, the size of the human hippocampus has been shown to increase in response to aerobic exercise. However, it is currently unknown what underlies these changes. Here we scanned sedentary, young to middle-aged human adults before and after a six-week exercise intervention using nine different neuroimaging measures of brain structure, vasculature, and diffusion. We then tested two different hypotheses regarding the nature of the underlying changes in the tissue. Surprisingly, we found no evidence of a vascular change as has been previously reported. Rather, the pattern of changes is better explained by an increase in myelination. Finally, we show hippocampal volume increase is temporary, returning to baseline after an additional six weeks without aerobic exercise. This is the first demonstration of a change in hippocampal volume in early to middle adulthood suggesting that hippocampal volume is modulated by aerobic exercise throughout the lifespan rather than only in the presence of age related atrophy. It is also the first demonstration of hippocampal volume change over a period of only six weeks, suggesting gross morphometric hippocampal plasticity occurs faster than previously thought.

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Section: Resultsmentioning

confidence: 86%

Multi-modal characterization of rapid anterior hippocampal volume increase associated with aerobic exercise

et al. 2016

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“…Gray-and white-matter identification based on the dynamic CTC information was shown to reliably identify two tissue classes unaffected by large intravascular T2* effects, as shown in Figure 2. The fact that voxels that would structurally be identified as gray matter were excluded (due to intravascular T2* effects) from the gray matter class in our analysis, is reflected in the lower gray/whitematter volume ratio (0.6) compared with that in the literature (Wenz et al, 1996). This approach also eliminates the need for co-registration of structural images and DSC images, which would add complexity to the analysis procedure.…”

Section: Discussionmentioning

confidence: 87%

“…Such a correlation would be expected if a significant portion of the tissue masks included tumor tissue, since high-grade gliomas are known to give significantly higher CBF and CBV values as compared with low-grade gliomas (Law et al, 2006). Other studies have also shown that normal-appearing regions of interest do not show altered CBV values compared with healthy controls in patients with primary brain tumors (Wenz et al, 1996). A further potential limitation in the methodology is that gray-and white-matter tissue clustering was based solely on the dynamic properties of the CTC, without any reference to structural images.…”

Section: Discussionmentioning

confidence: 99%

A Fully Automated Method for Quantitative Cerebral Hemodynamic Analysis Using DSC–MRI

Bjørnerud

Emblem

2010

J Cereb Blood Flow Metab

116

147

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Dynamic susceptibility contrast (DSC)-based perfusion analysis from MR images has become an established method for analysis of cerebral blood volume (CBV) in glioma patients. To date, little emphasis has, however, been placed on quantitative perfusion analysis of these patients, mainly due to the associated increased technical complexity and lack of sufficient stability in a clinical setting. The aim of our study was to develop a fully automated analysis framework for quantitative DSC-based perfusion analysis. The method presented here generates quantitative hemodynamic maps without user interaction, combined with automatic segmentation of normal-appearing cerebral tissue. Validation of 101 patients with confirmed glioma after surgery gave mean values for CBF, CBV, and MTT, extracted automatically from normal-appearing whole-brain white and gray matter, in good agreement with literature values. The measured age-and gender-related variations in the same parameters were also in agreement with those in the literature. Several established analysis methods were compared and the resulting perfusion metrics depended significantly on method and parameter choice. In conclusion, we present an accurate, fast, and automatic quantitative perfusion analysis method where all analysis steps are based on raw DSC data only.

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“…15 and 16). Most relevant to this study, MRI measures of CBV have been found to linearly correlate with basal glucose metabolism (18), and CBV has successfully detected the effects of aging (36) and hippocampal dysfunction in Alzheimer's and other diseases (20,21). Here we used an approach that generates CBV images with high spatial resolution (17), allowing us to visualize and analyze individual hippocampal subregions.…”

Section: Discussionmentioning

confidence: 99%

Imaging correlates of brain function in monkeys and rats isolates a hippocampal subregion differentially vulnerable to aging

Small

Chawla

Buonocore

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

260

254

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The hippocampal formation contains a distinct population of neurons organized into separate anatomical subregions. Each hippocampal subregion expresses a unique molecular profile accounting for their differential vulnerability to mechanisms of memory dysfunction. Nevertheless, it remains unclear which hippocampal subregion is most sensitive to the effects of advancing age. Here we investigate this question by using separate imaging techniques, each assessing different correlates of neuronal function. First, we used MRI to map cerebral blood volume, an established correlate of basal metabolism, in the hippocampal subregions of young and old rhesus monkeys. Second, we used in situ hybridization to map Arc expression in the hippocampal subregions of young and old rats. Arc is an immediate early gene that is activated in a behaviordependent manner and is correlated with spike activity. Results show that the dentate gyrus is the hippocampal subregion most sensitive to the effects of advancing age, which together with prior studies establishes a cross-species consensus. This pattern isolates the locus of age-related hippocampal dysfunction and differentiates normal aging from Alzheimer's disease. C ross-species studies have documented that the hippocampal formation, a structure vital for learning new memories, is particularly vulnerable to the aging process (1-3). A complex structure, the hippocampus is divided into separate but interconnected anatomic subregions: the entorhinal cortex, the dentate gyrus, the CA subfields, and the subiculum (4). Each hippocampal subregion contains a distinct population of neurons that express a unique molecular profile (5). This uniqueness can account for why each hippocampal subregion is differentially vulnerable to mechanisms of memory dysfunction (6). For example, transient hypoperfusion will cause hippocampaldependent memory deficits by targeting the CA1 subregion, whereas early Alzheimer's disease causes an overlapping memory deficit by targeting the entorhinal cortex.Although a number of studies suggest some cell loss with age (7, 8), compared to neurodegeneration, aging is characterized by a relative absence of frank cell death and lacks definitive histopathological markers (9). Rather, aging affects hippocampal performance by impairing normal neuronal physiology, expressed as synaptic dysfunction. This physiologic feature of aging accounts, to a large degree, for the difficulty identifying the primary hippocampal subregions most sensitive to normal aging. Not only is quantifying synaptic dysfunction difficult in postmortem tissue (10-12), but because of hippocampal interconnectivity, dysfunction in one subregion affects physiologic properties in other hippocampal subregions (1) and even throughout the circuit as a whole. Thus, assessing the functional integrity of each hippocampal subregion individually and simultaneously in living subjects is an effective approach for pinpointing the primary site of age-related hippocampal dysfunction.Most in vivo functional imaging technique...

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Age dependency of the regional cerebral blood volume (rCBV) measured with dynamic susceptibility contrast MR imaging (DSC)

Cited by 51 publications

References 15 publications

Multi-modal characterization of rapid anterior hippocampal volume increase associated with aerobic exercise

Multi-modal characterization of rapid anterior hippocampal volume increase associated with aerobic exercise

A Fully Automated Method for Quantitative Cerebral Hemodynamic Analysis Using DSC–MRI

Imaging correlates of brain function in monkeys and rats isolates a hippocampal subregion differentially vulnerable to aging

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