Background Deep brain stimulation (DBS) of the anterior limb of the internal capsule (ALIC) may be effective in treating depression. Parental verbal abuse has been linked to decreased fractional anisotropy (FA) of white matter and reduced FA correlated with depression and anxiety scores. Utilizing a nonhuman primate model of mood and anxiety disorders following disrupted mother-infant attachment, we examined whether adverse rearing conditions lead to white matter impairment of the ALIC. Methods We examined white matter integrity using Diffusion Tensor Imaging (DTI) on a 3T-MRI. Twenty-one adult male Bonnet macaques participated in this study: 12 were reared under adverse [variable foraging demand (VFD)] conditions whereas 9 were reared under normative conditions. We examined ALIC, posterior limb of the internal capsule (PLIC) and occipital white matter. Results VFD rearing was associated with significant reductions in FA in the ALIC with no changes evident in the PLIC or occipital cortex white matter. Conclusion Adverse rearing in monkeys persistently impaired frontal white matter tract integrity, a novel substrate for understanding affective susceptibility.
Background: Children exposed to early life stress (ELS) exhibit enlarged amygdala volume in comparison to controls. The primary goal of this study was to examine amygdala volumes in bonnet macaques subjected to maternal variable foraging demand (VFD) rearing, a well-established model of ELS. Preliminary analyses examined the interaction of ELS and the serotonin transporter gene on amygdala volume. Secondary analyses were conducted to examine the association between amygdala volume and other stress-related variables previously found to distinguish VFD and non-VFD reared animals.Methods: Twelve VFD-reared and nine normally reared monkeys completed MRI scans on a 3T system (mean age = 5.2 years).Results: Left amygdala volume was larger in VFD vs. control macaques. Larger amygdala volume was associated with: “high” cerebrospinal fluid concentrations of corticotropin releasing-factor (CRF) determined when the animals were in adolescence (mean age = 2.7 years); reduced fractional anisotropy (FA) of the anterior limb of the internal capsule (ALIC) during young adulthood (mean age = 5.2 years) and timid anxiety-like responses to an intruder during full adulthood (mean age = 8.4 years). Right amygdala volume varied inversely with left hippocampal neurogenesis assessed in late adulthood (mean age = 8.7 years). Exploratory analyses also showed a gene-by-environment effect, with VFD-reared macaques with a single short allele of the serotonin transporter gene exhibiting larger amygdala volume compared to VFD-reared subjects with only the long allele and normally reared controls.Conclusion: These data suggest that the left amygdala exhibits hypertrophy after ELS, particularly in association with the serotonin transporter gene, and that amygdala volume variation occurs in concert with other key stress-related behavioral and neurobiological parameters observed across the lifecycle. Future research is required to understand the mechanisms underlying these diverse and persistent changes associated with ELS and amygdala volume.
Background and Purpose: The display resolution of the Apple iPad® is 1024 × 768 pixels, which is greater than that required for generating the typical CT or MRI images. The purpose of this study is to determine if specific CT and MR sequences can be interpreted accurately on mobile device/PACS software platforms when compared to a traditional stationary high resolution monitor/PACS radiological workstation. If so, this allows radiologists to provide comparable interpretation as if they were onsite at an imaging center or hospital. Materials and Methods: This study is an investigator initiated, single site, retrospective, nonrandomized, IRB approved study. Five radiologists were included in this study. Each independently interpreted specific CT and MR sequences on traditional high-resolution LCD monitors via eFilm® software as well as an iPad® mobile device using Osirix® software program. Repeat interpretations were performed, with 4 weeks minimum interval between interpretations of each patient. This investigation included: 50 patients with CTA perfusion imaging, 50 patients with MRI of the brain, and 50 patients with MRI of the spine, which were image study orders generated through emergency room requests. Subsequently, interpretive results of each radiologist for each patient were statistically compared to evaluate for intra-observer and inter-observer reliability. Results: The parameters set within the CTA perfusion brain studies demonstrated excellent intra-observer variability. All of the parameters within the MRI brain studies demonstrated excellent intra-observer variability with a Cohen's kappa value > 0.75. The Cohen's kappa values for the board certified neuroradiologist demonstrated excellent variability for all parameters; the resident radiologists had good variability, with a majority of kappa values near 0.75. Conclusions: The data and statistical analysis demonstrated that portable mobile devices such as the Apple iPad® can display adequate resolution of CT and MRI sequences to accurately diagnose acute central nervous system injuries and other non-acute pathology.
Purpose Segmentation and diffusion-tensor-imaging of the corpus callosum (CC) have been linked to gait impairment. However, such measurements are impracticable in clinical routine. The purpose of this study was to evaluate the association between simple linear measurements of CC thickness with gait. Methods Two hundred and seventy-two community-dwelling subjects underwent neurological assessment and brain MRI. Mid-sagittal reformats of T1-weighted images were used to determine CC thickness. The association of measurements with clinical evaluation of gait was assessed by multivariate regression, controlling for numerous clinical and imaging confounders. Differences in CC thickness were, moreover, compared between subgroups with no, moderate or severe impairment of gait. Results In univariate analyses, thickness of the genu and body of CC but not the splenium were associated with postural stability (P<0.01). Multivariate regression revealed thickness of CC genu as the only imaging variable independently associated with gait (P=0.01). Genu thickness was significantly different between subjects with high and low (P=0.0003) or high and moderate (P=0.001) risk of fall. Conclusion Atrophy of the CC genu is an imaging marker of gait impairment in the elderly suggesting higher risk of fall. Simple linear measurements of CC can help in MRI evaluation of patients with gait impairment.
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