Methodological consensus on clinical proton MRS of the brain: Review and recommendations

© 2019 International Society for Magnetic Resonance in Medicine Proton MRS (1H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi-adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use

Explaining investments in sustainable land management: The role of various income sources in the smallholder farming systems of western Kenya

Smallholder farms in the humid highlands of East Africa are undergoing changes that question the notion of the rural space. Characterized by land degradation, increasing population pressure, intensive farming and continuous cropping in small plots, smallholder farmers have increasingly embraced additional forms of nonfarm income generation activities. The observed changes put to question parameters used in the analysis of smallholder farming systems in the region. In this paper, we endeavour to analyze how these changes in smallholder farming systems influence investments of proven sustainable land management practices. The paper is based on a study of 320 farm households comprising 494 plots in the western Kenya region. For cross-section data, use is made of the OLS and instrumental variable methods to explain investments in sustainable land management. In contrast to a number of recent studies, specification is made of non-farm income (NonFarmincome) as income from non-agricultural activities, and natural resource-based income (NRMincome) as income from natural resource management activities undertaken away from individual farm holdings. The NRMincome activities have an implication on landscape conservation, as they are mainly undertaken in communal and other public lands. Results show that non-farm income contributes to investments in soil prevention practices, contrary to the results of a number of studies looking broadly at off-farm incomes. The findings have implications for suitable policies for enhancing sustainable land management. This study argues that those policies need to focus on landscape level conservation, enhance non-farm income, and address impacts on communal lands and other common property regimes resulting from smallholder farmers’ natural resource management income strategies

Air Traffic Control Interface for Creating 4D Inbound Trajectories

It is to be expected that the task of an air traffic controller will change with the introduction of 4D (space and time) trajectories for aircraft. To support this new work, an interface for the manipulation of 4D trajectories has been created. The interface uses a time-space diagram – which shows progress of the aircraft along its planned track, in which conflict zones for conflict with other aircraft are presented, and a vertical path display, which presents the altitude along the planned track. In combination with a traditional plan-view display, and additional elements and tools in the displays to create a visual link between the paths displayed in the three displays, the interface enables the modification of a 4D planned trajectory for inbound aircraft. An experiment has been performed with a PC-based simulation. Two variants were tested, one in which the aircraft could only be controlled in the current sector, and one in which the speed (but not the path) of aircraft could be modified some time before these aircraft entered the sector; a practice expected to produce improvement of efficiency in small sectors. The results validate that the enhanced interface can be used to manage the air traffic safely and efficiently. It was also shown that the ability to manipulate the speed of an aircraft in the adjacent sector can significantly increase situation awareness and reduce controller workload

Designing for Joint Human-Automation Cognition Through a Shared Representation of 4D Trajectory Management

The current evolution of the ATM system, led by the SESAR programme in Europe and the NextGen programme in the US, is foreseen to bring a paradigm shift to the work domain of the air traffic controller. A focal point is the introduction of the 4D (space and time) trajectory as a means for strategic management rather than the current –hands on– method of control. In both programmes a central role is foreseen for the human operator, aided by higher levels of automation and advanced decision support tools. However, many other complex socio-technical domains have shown that the transition to higher levels of automation often introduces new problems, problems that are harder to resolve than the ones intended to solve in the first place. This paper presents one approach to the design of a shared representation for 4D trajectory management. The ultimate goal is to design a shared representation which forms the basis for both the design of the humanmachine interfaces and the rationale that guides the automation. It is expected that such a shared representation will greatly benefit the joint cognition of humans and automated agents in ATM and will mitigate breakdowns in coordination by design. A preliminary version of a joint cognitive representation for 4D trajectory management has been developed and is introduced in this paper. Future work will focus on the further development and refinement of shared representations by means of human-in-the-loop experiments

Methodological consensus on clinical proton MRS of the brain: Review and recommendations.

Proton MRS (1 H MRS) provides noninvasive, quantitative metabolite profiles of tissue and has been shown to aid the clinical management of several brain diseases. Although most modern clinical MR scanners support MRS capabilities, routine use is largely restricted to specialized centers with good access to MR research support. Widespread adoption has been slow for several reasons, and technical challenges toward obtaining reliable good-quality results have been identified as a contributing factor. Considerable progress has been made by the research community to address many of these challenges, and in this paper a consensus is presented on deficiencies in widely available MRS methodology and validated improvements that are currently in routine use at several clinical research institutions. In particular, the localization error for the PRESS localization sequence was found to be unacceptably high at 3 T, and use of the semi-adiabatic localization by adiabatic selective refocusing sequence is a recommended solution. Incorporation of simulated metabolite basis sets into analysis routines is recommended for reliably capturing the full spectral detail available from short TE acquisitions. In addition, the importance of achieving a highly homogenous static magnetic field (B0 ) in the acquisition region is emphasized, and the limitations of current methods and hardware are discussed. Most recommendations require only software improvements, greatly enhancing the capabilities of clinical MRS on existing hardware. Implementation of these recommendations should strengthen current clinical applications and advance progress toward developing and validating new MRS biomarkers for clinical use

Clinical proton MR spectroscopy in central nervous system disorders

<b>This article is free to read on the publishers website</b>\ud \ud A large body of published work shows that proton (hydrogen 1 [¹H]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of ¹H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of ¹H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which ¹H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units

Clinical proton MR spectroscopy in central nervous system disorders.

A large body of published work shows that proton (hydrogen 1 [(1)H]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of (1)H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of (1)H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which (1)H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units