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Atrophy Rates (atrophy + rate)

Distribution by Scientific Domains
Medical Sciences91%

Selected Abstracts

Cerebral Atrophy Measurement in Clinically Isolated Syndromes and Relapsing Remitting Multiple Sclerosis: A Comparison of Registration-Based Methods

JOURNAL OF NEUROIMAGING, Issue 1 2007
Valerie M. Anderson BSc
ABSTRACT Background and Purpose. Brain atrophy is a proposed marker of disease progression in multiple sclerosis (MS). Many magnetic resonance imaging-based methods of atrophy quantification exist, but their relative sensitivity and precision is unclear. Our aim was to compare atrophy rates from the brain boundary shift integral (BBSI), structural image evaluation, using normalization of atrophy (SIENA) (both registration-based methods) and segmented brain volume difference, in patients with clinically isolated syndromes (CIS), relapsing remitting MS (RRMS), and controls. Methods. Thirty-seven CIS patients, 30 with early RRMS and 16 controls had T1-weighted volumetric imaging at baseline and 1 year. Brain atrophy rates were determined using segmented brain volume difference, BBSI, and SIENA. Results. BBSI and SIENA were more precise than subtraction of segmented brain volumes and were more sensitive distinguishing RRMS subjects from controls. A strong correlation was observed between BBSI and SIENA. Atrophy rates were greater in CIS and RRMS subjects than controls (RRMS P < .001). With all methods, significantly greater atrophy rates were observed in CIS patients who developed clinically definite MS relative to subjects who did not. Conclusion. Registration-based techniques are more precise and sensitive than segmentation-based methods in measuring brain atrophy, with BBSI and SIENA providing comparable results. [source]

Methodological considerations for measuring rates of brain atrophy

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2003
Jeffrey L. Gunter PhD
Abstract Purpose To systematically compare two techniques for measuring brain atrophy rates from serial magnetic resonance imaging (MRI) studies. Materials and Methods Using the separation in atrophy rate between cohorts of cognitively normal elderly subjects and patients with Alzheimer's disease (AD) as the gold standard, we evaluated 1) different methods of computing volume change; 2) different methods for steps in image preprocessing,intensity normalization, alignment mask used, and bias field correction; 3) the effect of MRI acquisition hardware changes; and 4) the sensitivity of the method to variations in initial manual volume editing. For each of the preceding evaluations, measurements of whole-brain and ventricular atrophy rates were calculated. Results In general, greater separation between the clinical groups was seen with ventricular rather than whole-brain measures. Surprisingly, neither the use of bias field correction nor a major hardware change between the scan pairs affected group separation. Conclusion Atrophy rate measurements from serial MRI are candidates for use as surrogate markers of disease progression in AD and other dementing neurodegenerative disorders. The final method has excellent precision and accurately captures the expected biology of AD,arguably the two most important features if this technique is to be used as a biomarker of disease progression. J. Magn. Reson. Imaging 2003;18:16,24. © 2003 Wiley-Liss, Inc. [source]

Gray matter atrophy in multiple sclerosis: A longitudinal study

ANNALS OF NEUROLOGY, Issue 3 2008
Elizabeth Fisher Ph.D.
Objective To determine gray matter (GM) atrophy rates in multiple sclerosis (MS) patients at all stages of disease, and to identify predictors and clinical correlates of GM atrophy. Methods MS patients and healthy control subjects were observed over 4 years with standardized magnetic resonance imaging (MRI) and neurological examinations. Whole-brain, GM, and white matter atrophy rates were calculated. Subjects were categorized by disease status and disability progression to determine the clinical significance of atrophy. MRI predictors of atrophy were determined through multiple regression. Results Subjects included 17 healthy control subjects, 7 patients with clinically isolated syndromes, 36 patients with relapsing-remitting MS (RRMS), and 27 patients with secondary progressive MS (SPMS). Expressed as fold increase from control subjects, GM atrophy rate increased with disease stage, from 3.4-fold normal in clinically isolated syndromes patients converting to RRMS to 14-fold normal in SPMS. In contrast, white matter atrophy rates were constant across all MS disease stages at approximately 3-fold normal. GM atrophy correlated with disability. MRI measures of focal and diffuse tissue damage accounted for 62% of the variance in GM atrophy in RRMS, but there were no significant predictors of GM atrophy in SPMS. Interpretation Gray matter tissue damage dominates the pathological process as MS progresses, and underlies neurological disabillity. Imaging correlates of gray matter atrophy indicate that mechanisms differ in RRMS and SPMS. These findings demonstrate the clinical relevance of gray matter atrophy in MS, and underscore the need to understand its causes. Ann Neurol 2008 [source]

Clinical application of measurement of hippocampal atrophy in degenerative dementias

HIPPOCAMPUS, Issue 6 2009
Josephine Barnes
Abstract Hippocampal atrophy is a characteristic and early feature of Alzheimer's disease. Volumetry of the hippocampus using T1-weighted magnetic resonance imaging (MRI) has been used not only to assess hippocampal involvement in different neurodegenerative diseases as a potential diagnostic biomarker, but also to understand the natural history of diseases, and to track changes in volume over time. Assessing change in structure circumvents issues surrounding interindividual variability and allows assessment of disease progression. Disease-modifying effects of putative therapies are important to assess in clinical trials and are difficult using clinical scales. As a result, there is increasing use of serial MRI in trials to detect potential slowing of atrophy rates as an outcome measure. Automated and yet reliable methods of quantifying such change in the hippocampus would therefore be very valuable. Algorithms capable of measuring such changes automatically have been developed and may be applicable to predict decline to a diagnosis of dementia in the future. This article details the progress in using MRI to understand hippocampal changes in the degenerative dementias and also describes attempts to automate hippocampal segmentation in these diseases. © 2009 Wiley-Liss, Inc. [source]

Methodological considerations for measuring rates of brain atrophy

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2003
Jeffrey L. Gunter PhD
Abstract Purpose To systematically compare two techniques for measuring brain atrophy rates from serial magnetic resonance imaging (MRI) studies. Materials and Methods Using the separation in atrophy rate between cohorts of cognitively normal elderly subjects and patients with Alzheimer's disease (AD) as the gold standard, we evaluated 1) different methods of computing volume change; 2) different methods for steps in image preprocessing,intensity normalization, alignment mask used, and bias field correction; 3) the effect of MRI acquisition hardware changes; and 4) the sensitivity of the method to variations in initial manual volume editing. For each of the preceding evaluations, measurements of whole-brain and ventricular atrophy rates were calculated. Results In general, greater separation between the clinical groups was seen with ventricular rather than whole-brain measures. Surprisingly, neither the use of bias field correction nor a major hardware change between the scan pairs affected group separation. Conclusion Atrophy rate measurements from serial MRI are candidates for use as surrogate markers of disease progression in AD and other dementing neurodegenerative disorders. The final method has excellent precision and accurately captures the expected biology of AD,arguably the two most important features if this technique is to be used as a biomarker of disease progression. J. Magn. Reson. Imaging 2003;18:16,24. © 2003 Wiley-Liss, Inc. [source]

Cerebral Atrophy Measurement in Clinically Isolated Syndromes and Relapsing Remitting Multiple Sclerosis: A Comparison of Registration-Based Methods

JOURNAL OF NEUROIMAGING, Issue 1 2007
Valerie M. Anderson BSc
ABSTRACT Background and Purpose. Brain atrophy is a proposed marker of disease progression in multiple sclerosis (MS). Many magnetic resonance imaging-based methods of atrophy quantification exist, but their relative sensitivity and precision is unclear. Our aim was to compare atrophy rates from the brain boundary shift integral (BBSI), structural image evaluation, using normalization of atrophy (SIENA) (both registration-based methods) and segmented brain volume difference, in patients with clinically isolated syndromes (CIS), relapsing remitting MS (RRMS), and controls. Methods. Thirty-seven CIS patients, 30 with early RRMS and 16 controls had T1-weighted volumetric imaging at baseline and 1 year. Brain atrophy rates were determined using segmented brain volume difference, BBSI, and SIENA. Results. BBSI and SIENA were more precise than subtraction of segmented brain volumes and were more sensitive distinguishing RRMS subjects from controls. A strong correlation was observed between BBSI and SIENA. Atrophy rates were greater in CIS and RRMS subjects than controls (RRMS P < .001). With all methods, significantly greater atrophy rates were observed in CIS patients who developed clinically definite MS relative to subjects who did not. Conclusion. Registration-based techniques are more precise and sensitive than segmentation-based methods in measuring brain atrophy, with BBSI and SIENA providing comparable results. [source]

Brain atrophy rates in Parkinson's disease with and without dementia using serial magnetic resonance imaging

MOVEMENT DISORDERS, Issue 12 2005
Emma J. Burton PhD
Abstract Increased rates of brain atrophy are seen in Alzheimer's disease, but whether rates are similarly increased in other dementias such as Parkinson's disease dementia (PDD) has not been well examined. We determined the rates of brain atrophy using serial magnetic resonance imaging (MRI) in PDD and compared this finding to rates seen in cognitively intact Parkinson's disease (PD) patients and age-matched control subjects. Thirty-one patients (PD = 18, PDD = 13) and 24 age-matched controls underwent serial volumetric 1.5 T MRI scans, approximately 1 year apart. Baseline and repeat scans were registered and quantification of the brain boundary shift integral was used to determine whole-brain atrophy rates. Rates of brain atrophy were significantly increased in PDD (1.12 ± 0.98%/year) compared to PD (0.31 ± 0.69%/year; P = 0.018) and control subjects (0.34 ± 0.76%/year; P = 0.015). There were no differences in atrophy rates between controls and PD (P = 0.79). No correlations between increased atrophy rates and age or dementia severity (Mini-Mental State Examination score) were observed. Serial MRI may be a useful tool for monitoring disease progression in PDD and further studies should investigate its utility for early diagnosis. © 2005 Movement Disorder Society [source]

Gray matter atrophy in multiple sclerosis: A longitudinal study

ANNALS OF NEUROLOGY, Issue 3 2008
Elizabeth Fisher Ph.D.
Objective To determine gray matter (GM) atrophy rates in multiple sclerosis (MS) patients at all stages of disease, and to identify predictors and clinical correlates of GM atrophy. Methods MS patients and healthy control subjects were observed over 4 years with standardized magnetic resonance imaging (MRI) and neurological examinations. Whole-brain, GM, and white matter atrophy rates were calculated. Subjects were categorized by disease status and disability progression to determine the clinical significance of atrophy. MRI predictors of atrophy were determined through multiple regression. Results Subjects included 17 healthy control subjects, 7 patients with clinically isolated syndromes, 36 patients with relapsing-remitting MS (RRMS), and 27 patients with secondary progressive MS (SPMS). Expressed as fold increase from control subjects, GM atrophy rate increased with disease stage, from 3.4-fold normal in clinically isolated syndromes patients converting to RRMS to 14-fold normal in SPMS. In contrast, white matter atrophy rates were constant across all MS disease stages at approximately 3-fold normal. GM atrophy correlated with disability. MRI measures of focal and diffuse tissue damage accounted for 62% of the variance in GM atrophy in RRMS, but there were no significant predictors of GM atrophy in SPMS. Interpretation Gray matter tissue damage dominates the pathological process as MS progresses, and underlies neurological disabillity. Imaging correlates of gray matter atrophy indicate that mechanisms differ in RRMS and SPMS. These findings demonstrate the clinical relevance of gray matter atrophy in MS, and underscore the need to understand its causes. Ann Neurol 2008 [source]