The developing human brain shows rapid myelination and axonal changes during childhood, adolescence and early adulthood, requiring successive evaluations to determine normative values for potential pathological assessment. Fiber characteristics can be examined by axial and radial diffusivity procedures, which measure water diffusion parallel and perpendicular to axons, and primarily show axonal status and myelin changes, respectively. Such measures are lacking from wide-spread sites for the developing brain. Diffusion tensor imaging data were acquired from 30 healthy subjects (age, 17.7±4.6, range 8–24 years; body-mass-index, 21.5±4.5 kg/m2; 18 male) using a 3.0-Tesla MRI scanner. Diffusion tensors were calculated, principal eigenvalues determined, and axial and radial diffusivity maps calculated and normalized to a common space. A set of regions-of-interest were outlined from wide-spread brain areas within rostral, thalamic, hypothalamic, cerebellar, and pontine regions, and average diffusivity values were calculated using normalized diffusivity maps and these regions-of-interest masks. Age-related changes were assessed with Pearson’s correlations, and gender differences evaluated with Student’s t-tests. Axial and radial diffusivity values declined with age in the majority of brain areas, except for mid hippocampus, where axial diffusivity values correlated positively with age. Gender differences emerged within putamen, thalamic, hypothalamic, cerebellar, limbic, temporal, and other cortical sites. Documentation of normal axial and radial diffusivity values will help assess disease-related tissue changes. Axial and radial diffusivity change with age, with fiber structure and organization differing between sexes in several brain areas. The findings may underlie gender-based functional characteristics, and mandate partitioning age- and gender-related changes during developmental brain pathology evaluation.

AimsHeart failure (HF) is accompanied by diminished cognitive, motor, learning, emotional, and planning deficits, which are associated with increased morbidity and mortality. A basal ganglia structure, the putamen, serves many functions that are affected in HF, but its global or localized structural integrity is unknown. Our aim was to evaluate global and regional putamen volume differences in HF over control subjects. Methods and resultsWe collected two high-resolution T1-weighted scans from 16 HF patients (age, 54.1 + 8.3 years; 12 males; left ventricular ejection fraction, 27.8 + 6.8%) and 32 control subjects (52.4 + 7.3 years; 24 males) using a 3.0 T magnetic resonance imaging scanner. After realigning, averaging, and reorienting the T1-weighted volumes into a common space, the structures were manually outlined, tracings were normalized for head size, volumes calculated, and surface models generated. Demographic data were compared between groups with x 2 and independent samples t-tests, global putamen volumes were evaluated using independent samples t-tests, and regional differences were examined with surface morphometry. No significant differences in age or sex appeared between groups, but body mass index differed significantly (P ¼ 0.008). Heart failure patients showed significantly lower left (controls vs. HF; 4842.1 + 740.0 vs. 4224.1 + 894.4 mm 3 , P ¼ 0.014) and right (4769.3 + 651.9 vs. 4193.7 + 876.2 mm 3 , P ¼ 0.014) global putamen volumes than controls, with localized reductions in bilateral rostral, mid-dorsal, and medial-caudal regions (left, P , 0.003; right, P , 0.0002). ConclusionPutamen structures showed global and localized volume reductions in HF over controls. The localized volume losses suggest deficits in motor and neuropsychological functions, which are evident in HF subjects, and may be due to hypoxic and ischaemic processes targeting these areas.--

Congenital central hypoventilation syndrome (CCHS) patients show hypoventilation during sleep and severe autonomic impairments, including aberrant cardiovascular regulation. Abnormal sympathetic patterns, together with increased and variable CO 2 levels, lead to the potential for sustained cerebral vasculature changes. We performed high-resolution T1-weighted imaging in 13 CCHS and 31 control subjects using a 3.0-Tesla magnetic resonance imaging scanner, and evaluated resting basilar and bilateral middle cerebral artery cross-sections. Two T1-weighted image series were acquired; images were averaged and reoriented to common space, and regions containing basilar and both middle cerebral arteries were oversampled. Cross-sections of the basilar and middle cerebral arteries were manually outlined to calculate cross-sectional areas, and differences between and within groups were evaluated. Basilar arteries in CCHS were significantly dilated over control subjects, but both middle cerebral artery cross-sections were similar between groups. No significant differences appeared between left and right middle cerebral arteries within either group. Basilar artery dilation may result from differential sensitivity to high CO 2 over other vascular beds, damage to serotonergic or other chemosensitive cells accompanying the artery, or enhanced microvascular resistance, and that dilation may impair tissue perfusion, leading to further neural injury in CCHS.

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