Biomedical subjects

Michael Moseley

Publications and source records attributed to Michael Moseley.

7 recordsLinked to original sources

PubMed2006

Magnetic resonance imaging profiles predict clinical response to early reperfusion: the diffusion and perfusion imaging evaluation for understanding stroke evolution (DEFUSE) study.

OBJECTIVE: To determine whether prespecified baseline magnetic resonance imaging (MRI) profiles can identify stroke patients who have a robust clinical response after early reperfusion when treated 3 to 6 hours after symptom onset. METHODS: We conducted a prospective, multicenter study of 74 consecutive stroke patients admitted to academic stroke centers in North America and Europe. An MRI scan was obtained immediately before and 3 to 6 hours after treatment with intravenous tissue plasminogen activator 3 to 6 hours after symptom onset. Baseline MRI profiles were used to categorize patients into subgroups, and clinical responses were compared based on whether early reperfusion was achieved. RESULTS: Early reperfusion was associated with significantly increased odds of achieving a favorable clinical response in patients with a perfusion/diffusion mismatch (odds ratio, 5.4; p = 0.039) and an even more favorable response in patients with the Target Mismatch profile (odds ratio, 8.7; p = 0.011). Patients with the No Mismatch profile did not appear to benefit from early reperfusion. Early reperfusion was associated with fatal intracranial hemorrhage in patients with the Malignant profile. INTERPRETATION: For stroke patients treated 3 to 6 hours after onset, baseline MRI findings can identify subgroups that are likely to benefit from reperfusion therapies and can potentially identify subgroups that are unlikely to benefit or may be harmed.

Aged↗

PubMed2005

White matter changes in mild cognitive impairment and AD: A diffusion tensor imaging study.

Diffusion tensor imaging (DTI) can detect, in vivo, the directionality of molecular diffusion and estimate the microstructural integrity of white matter (WM) tracts. In this study, we examined WM changes in patients with Alzheimer's disease (AD) and in subjects with amnestic mild cognitive impairment (MCI) who are at greater risk for developing AD. A DTI index of WM integrity, fractional anisotropy (FA), was calculated in 14 patients with probable mild AD, 14 participants with MCI and 21 elderly healthy controls (NC). Voxel-by-voxel comparisons showed significant regional reductions of FA in participants with MCI and AD compared to controls in multiple posterior white matter regions. Moreover, there was substantial overlap of locations of regional decrease in FA in the MCI and AD groups. These data demonstrate that white matter changes occur in MCI, prior to the development of dementia.

Aged↗

PubMed2004

Magnetic resonance imaging and surgical repair of cleft palate in a four-week-old canine (Canis familiaris): an animal model for cleft palate repair.

Successful cleft palate repair (palatoplasty) was accomplished in a male canine pup from a kindred with autosomal recessive transmission for a complete cleft palate phenotype. This case represents the potential application of a new animal model for cleft palate repair. This reproducible congenital defect provides a clinically relevant model to improve research into the human anomaly, as compared with previous iatrogenic or teratogenically induced animal models. This case report presents the basis for new repair techniques and for studying the genetic basis of the cleft palate defect.

Animals↗

PubMed2003

White matter tract alterations in fragile X syndrome: preliminary evidence from diffusion tensor imaging.

Fragile X syndrome, the most common form of hereditary mental retardation, causes disruption in the development of dendrites and synapses, the targets for axonal growth in the central nervous system. This disruption could potentially affect the development, wiring, and targeting of axons. The current study utilized diffusion tensor imaging (DTI) to investigate whether white matter tract integrity and connectivity are altered in fragile X syndrome. Ten females with a diagnosis of fragile X syndrome and ten, age matched, female control subjects underwent diffusion weighted MRI scans. A whole brain analysis of fractional anisotropy (FA) values was performed using statistical parametric mapping (SPM). A follow-up, regions-of-interest analysis also was conducted. Relative to controls, females with fragile X exhibited lower FA values in white matter in fronto-striatal pathways, as well as in parietal sensory-motor tracts. This preliminary study suggests that regionally specific alterations of white matter integrity occur in females with fragile X. Aberrant white matter connectivity in these regions is consistent with the profile of cognitive and behavioral features of fragile X syndrome, and potentially provide additional insight into the detrimental effects of suboptimal levels of FMRP in the developing brain.

Adolescent↗

PubMed2002

Diffusion-tensor imaging of cognitive performance.

MR methods have for some years been used to assess cognitive performance. Recently, studies have shown that diffusion-tensor imaging (DTI), which provides noninvasive maps of microscopic structural information of oriented tissue in vivo, is finding utility in studies of cognition in the normal and abnormal aging population. These studies suggest that water proton nonrandom, anisotropic diffusion measured by DTI is highly sensitive to otherwise subtle disease processes not easily seen with conventional MRI tissue contrast mechanisms and raises new issues of the role of MR in assessing cognitive potential.

Alzheimer Disease↗

PubMedDate not supplied

Diffusion tensor imaging and aging - a review.

Diffusion-tensor imaging (DTI) non-invasively provides maps of microscopic structural information of oriented tissue in vivo, which is finding utility in studies of the aging population. In contrast to the white matter maturation process, investigators have observed significant declines in the white matter ordering in normal as well as in abnormal aging. These studies suggest that water proton non-random, anisotropic diffusion measured by DTI is highly sensitive to otherwise subtle disease processes not normally seen with conventional MRI tissue contrast mechanisms.

Adolescent↗

PubMedDate not supplied

Automated method for generating the arterial input function on perfusion-weighted MR imaging: validation in patients with stroke.

BACKGROUND AND PURPOSE: The choice of arterial input function (AIF) can have a profound effect on the blood flow maps generated on perfusion-weighted MR imaging (PWI). Automation of this process could substantially reduce operator dependency, increase consistency, and accelerate PWI analysis. We created an automated AIF identification program (auto-AIF) and validated its performance against conventional manual methods. METHODS: We compared the auto-AIF against manually derived AIFs from multisection PWIs of 22 patients with stroke. Time to peak, curve width, curve height, and voxel location determined with both techniques were compared. The time to maximum of the tissue residue function (Tmax) and cerebral blood flow (CBF) were computed on a per-pixel basis for each AIF. Spatial patterns of 528 map pairs were compared by computing Pearson correlation coefficients between maps generated with each method. RESULTS: All auto-AIF-derived PWI map parameters, including bolus peak, width, and height, were consistently superior to manually derived ones. Reproducibility of the auto-AIF-based Tmax maps was excellent (r = 1.0). Paired Tmax maps and CBF maps from both techniques were well correlated (r = 0.82). Time to identify the AIF was significantly shorter with the auto-AIF method than with the manual technique (mean difference, 72 seconds; 95% confidence interval: 54, 89 seconds). CONCLUSION: An automated program that identifies the AIF is feasible and can create reliably reproducible and accurate Tmax and CBF maps. Automation of this process could reduce PWI analysis time and increase consistency and may allow for more effective use of PWI in the evaluation of acute stroke.

Adult↗