We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T 1 -weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K trans (min ؊1 ); b) the volume of extravascular extracellular space (EES) per unit volume of tissue v e (0 F v e F 1); and c) the flux rate constant between EES and plasma k ep (min ؊1 ). The rate constant is the ratio of the transfer constant to the EES (k ep ‫؍‬ K trans / v e ). Under flow-limited conditions K trans equals the blood plasma flow per unit volume of tissue; under permeability-limited conditions K trans equals the permeability surface area product per unit volume of tissue. We relate these quantities to previously published work from our groups; our future publications will refer to these standardized terms, and we propose that these be adopted as international standards.

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The present results suggest that, at least for some cognitive functions, deficient development and/or loss of NAWM after CRT may provide a neuroanatomical substrate for the adverse impact of a young age at the time of CRT.

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Although previous studies have documented a significant risk of intellectual loss after treatment for childhood medulloblastoma (MED), the pathophysiology underlying this process is poorly understood. The purpose of this study was to test the hypotheses that (1) patients treated for MED in childhood have reduced volumes of normal white matter (NWM) related to their treatment with craniospinal irradiation with or without chemotherapy, and (2) deficits in NWM among patients surviving MED can at least partially explain deficits in their intellectual performance. Eighteen pediatric patients previously treated for MED were matched on the basis of age at the time of evaluation to 18 patients previously treated for low‐grade posterior fossa tumors with surgery alone (mean difference, 3.7 months). Evaluations were conducted with age‐appropriate neurocognitive testing and quantitative magnetic resonance imaging by using a novel automated segmentation and classification algorithm constructed from a hybrid neural network. Patients treated for MED had significantly less NWM (p < 0.01) and significantly lower Full‐Scale IQ values than those treated for low‐grade tumors (mean, 82.1 vs 92.9). In addition, NWM had a positive and statistically significant association with Full‐Scale IQ among the patients treated for MED. We conclude that irradiation‐ or chemotherapy‐induced destruction of NWM can at least partially explain intellectual and academic achievement deficits among MED survivors.

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Community participation is considered important in primary health care development and there is some evidence to suggest it results in positive health outcomes. Through a process of synthesising existing evidence for the effectiveness of community participation in terms of health outcomes we identified several conceptual areas of confusion. This paper builds on earlier work to disentangle the conceptual gaps in this area, and clarify our common understanding of community participation. We conducted a research synthesis of 689 empirical studies in the literature linking rural community participation and health outcomes. The 37 final papers were grouped and analysed according to: contextual factors; the conceptual approach to community participation (using a modification of an existing typology); community participation process; level of evidence; and outcomes reported. Although there is some evidence of benefit of community participation in terms of health outcomes, we found only a few studies demonstrating higher levels of evidence. However, it is clear that absence of evidence of effect is not necessarily the same as absence of an effect. We focus on areas of debate and lack of clarity in the literature. Improving our understanding of community participation and its role in rural primary health care service design and delivery will increase the likelihood of genuine community-health sector partnerships and more responsive health services for rural communities.