The UN Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) - An ocean science-policy interface standing the test of time.

Addressing the wide range of marine pollution problems facing the global ocean requires a continual transfer of credible, relevant and timely scientific information to policy and decision makers in coastal and ocean management. The United Nations GESAMP (Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection) is a long-standing scientific advisory group providing such information on a wide range of marine topics and emerging issues of concern to ten UN Sponsoring Organizations. This paper presents an overview of GESAMPs operation and examples of its current work. The group's scientific output is often cited by national governments, inter-governmental groups, and a range of non-governmental groups. Given the growing concerns about ocean health and the impacts of many stressors in an era of climate change, the development of timely and effective ocean policy and decision making would benefit from wider recognition and application of GESAMPs work.

Coil setup optimization for 2D-SENSE whole-heart coronary imaging.

Accelerated "whole-heart" coronary imaging with sensitivity encoding applied in both phase encoding directions (2D-SENSE) was investigated. In order to maximize the signal-to-noise ratio (SNR), coil configuration optimization was performed. To this end, 10 practical coil configurations each consisting of six standard coil elements were investigated and the local SNR was assessed by means of phantom experiments. Based on the experimental data, a symmetric configuration was found to yield the highest SNR. In a volunteer study, 2D-SENSE coronary images were obtained with total reduction factors of 3 and 4. Excellent depiction of the right and left coronary systems was possible in all cases.

Improved artery delineation in dual-stack coronary magnetic resonance angiography using parallel imaging at 3 T.

PURPOSE: To improve vessel sharpness and T2 preparation (T2Prep) in dual-stack three-dimensional coronary magnetic resonance angiography (MRA) by shortening the time delays between the magnetization preparation pulses and the imaging stacks using sensitivity encoding (SENSE) at 3 T. MATERIALS AND METHODS: By combining dual-stack three-dimensional coronary MRA with the parallel imaging technique SENSE at 3 T, the acquisition duration of each three-dimensional imaging stack was shortened by a factor of 2. The proposed technique was implemented and tested in experiments with a moving phantom and in measurements on six healthy volunteers. RESULTS: The time delay between the navigator, T2Prep, and second imaging stack was reduced by 37%, relative to conventional dual-stack angiography without parallel imaging. This enabled the achievement of comparable high-vessel sharpness values for the left and the right coronary arteries relative to values known from conventional single-stack three-dimensional coronary MRA at 3 T. CONCLUSION: Parallel imaging allows for improved vessel visualization in dual-stack coronary MRA, given shorter temporal delays between navigator, T2Prep, and the actual image acquisitions, and thus considerably facilitates simultaneous acquisition of high-resolution angiograms of the left and right coronary systems.

Improved three-dimensional free-breathing coronary magnetic resonance angiography using gadocoletic acid (B-22956) for intravascular contrast enhancement.

PURPOSE: To evaluate gadocoletic acid (B-22956), a gadolinium-based paramagnetic blood pool agent, for contrast-enhanced coronary magnetic resonance angiography (MRA) in a Phase I clinical trial, and to compare the findings with those obtained using a standard noncontrast T2 preparation sequence. MATERIALS AND METHODS: The left coronary system was imaged in 12 healthy volunteers before B-22956 application and 5 (N = 11) and 45 (N = 7) minutes after application of 0.075 mmol/kg of body weight (BW) of B-22956. Additionally, imaging of the right coronary system was performed 23 minutes after B-22956 application (N = 6). A three-dimensional gradient echo sequence with T2 preparation (precontrast) or inversion recovery (IR) pulse (postcontrast) with real-time navigator correction was used. Assessment of the left and right coronary systems was performed qualitatively (a 4-point visual score for image quality) and quantitatively in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel sharpness, visible vessel length, maximal luminal diameter, and the number of visible side branches. RESULTS: Significant (P < 0.01) increases in SNR (+42%) and CNR (+86%) were noted five minutes after B-22956 application, compared to precontrast T2 preparation values. A significant increase in CNR (+40%, P < 0.05) was also noted 45 minutes postcontrast. Vessels (left anterior descending artery (LAD), left coronary circumflex (LCx), and right coronary artery (RCA)) were also significantly (P < 0.05) sharper on postcontrast images. Significant increases in vessel length were noted for the LAD (P < 0.05) and LCx and RCA (both P < 0.01), while significantly more side branches were noted for the LAD and RCA (both P < 0.05) when compared to precontrast T2 preparation values. CONCLUSION: The use of the intravascular contrast agent B-22956 substantially improves both objective and subjective parameters of image quality on high-resolution three-dimensional coronary MRA. The increase in SNR, CNR, and vessel sharpness minimizes current limitations of coronary artery visualization with high-resolution coronary MRA.

Sensitivity-encoded coronary MRA at 3T.

Long scan times are still a main limitation in free-breathing navigator-gated 3D coronary MR angiography (MRA). Unlike other MRI applications, high-resolution coronary MRA has not been amenable to acceleration by parallel imaging techniques due to signal-to-noise ratio (SNR) concerns. In the present work, mitigating SNR limitations by the transition to higher static magnetic field strength is proposed, thus enabling scan time reduction by the parallel sensitivity encoding (SENSE) technique. The study reports the implementation and evaluation of free-breathing navigator-gated 3D coronary MRA with SENSE at 3T. Results from 11 healthy subjects indicate that the approach permits significant scan time reduction in MRA of the left and right coronary systems. Quantitative image analysis and visual grading suggest that two-fold scan acceleration can be accomplished at nearly preserved image quality. The additional experiments appear to demonstrate that parallel MRA equally permits enhancing volume coverage and spatial resolution while maintaining scan time.

Performance of a new gadolinium-based intravascular contrast agent in free-breathing inversion-recovery 3D coronary MRA.

In three-dimensional (3D) coronary magnetic resonance angiography (MRA), the in-flow contrast between the coronary blood and the surrounding myocardium is attenuated as compared to thin-slab two-dimensional (2D) techniques. The application of a gadolinium (Gd)-based intravascular contrast agent may provide an additional source of signal and contrast by reducing T(1blood) and supporting the visualization of more distal or branching segments of the coronary arterial tree. In six healthy adults, the left coronary artery (LCA) system was imaged pre- and postcontrast with a 0.075-mmol/kg bodyweight dose of the intravascular contrast agent B-22956. For imaging, an optimized free-breathing, navigator-gated and -corrected 3D inversion recovery (IR) sequence was used. For comparison, state-of-the-art baseline 3D coronary MRA with T(2) preparation for non-exogenous contrast enhancement was acquired. The combination of IR 3D coronary MRA, sophisticated navigator technology, and B-22956 allowed for an extensive visualization of the LCA system. Postcontrast, a significant increase in both the signal-to-noise ratio (SNR; 46%, P < 0.05) and contrast-to-noise ratio (CNR; 160%, P < 0.01) was observed, while vessel sharpness of the left anterior descending (LAD) artery and the left coronary circumflex (LCX) were improved by 20% (P < 0.05) and 18% (P < 0.05), respectively.

Single breath-hold extended free-breathing navigator-gated three-dimensional coronary MRA.

PURPOSE: To acquire the center of k-space while extending three-dimensional free-breathing navigator-gated coronary magnetic resonance (MR) angiography by an initial single breath-hold. MATERIALS AND METHODS: This approach was successfully applied in eight healthy adult subjects. Resulting images were compared with conventionally acquired free-breathing navigator-gated MR angiograms. RESULTS: The acquisition of k-space center during the single breath-hold resulted in a 26% increase (P < 0.05) of signal-to-noise ratio. Visible length of the right coronary artery, as well as contrast-to-noise ratio between the blood and the myocardial muscle, were identical. CONCLUSION: The breath-hold extension was shown to be a valuable technique that may be combined with first-pass contrast-enhanced MR imaging.

Effects of Self-Guided Snorkeling Trails on Corals in a Tropical Marine Park.

Underwater trails are intended as interpretative tools in marine parks, but concentrating divers and snorkelers in defined areas may negatively affect the surrounding environment. We examined spatial and temporal patterns in the effects of use of underwater trails on coral reef flats in the Great Barrier Reef Marine Park, Australia. Changes in benthic assemblages were assessed on two new trails used by snorkelers, two unused (control) trails, and two undisturbed areas. Total percent coral cover, numbers of broken colonies, and living coral fragments were counted 6 months before and 6 months after the new trails began to be used. Spatial patterns of effects around concentrated nodes of use were determined by stratified sampling around and away from the interpretative signs within each trail. Despite comparatively low levels of use (approximately 15 snorkelers per trail per week), snorkelers caused significant damage to corals along the trails. Branching corals (non-Acropora branching corals and Millepora spp.) were most affected. More damage occurred near the interpretative signs than elsewhere on the trails. The numbers of broken branches and damaged coral colonies in the snorkeling trails increased rapidly but stabilized within 2 months of the commencement of use. There was no significant change in overall benthic assemblages within the trails after 6 months of use by snorkelers. Although concentrating snorkelers within confined trails caused increased damage to corals, the effects can be mitigated by appropriate design and placement of the trails and by managing the behavior of snorkelers. Interpretative information should warn users about the damage they may cause when swimming along the trails. Managing the behavior of snorkelers in the water is likely to be more effective in reducing damage than simply applying fixed limits to the amount of use the trails receive.

RESUMEN: Los senderos submarinos tienen la intención de servir como herramientas interpretativas en los parques marinos, pero la concentración de buzos y buceadores libres en áreas definidas puede tener un efecto negativo en el ambiente de los alrededores. Examinamos los patrones temporales y espaciales de los efectos del uso de senderos submarinos en relieves de arrecifes de coral en el arrecife del Parque Marino de la Gran Barrera de Arrecifes en Australia. Los cambios en los ensamblajes bénticos fueron evaluados en dos senderos nuevos usados por buceadores libres, dos senderos sin usar (controles) y dos áreas sin perturbar. Evaluamos el porcentaje de cobertura de coral, el número de colonias rotas, y fragmentos de coral vivo 6 meses antes y seis meses después de que se iniciara el uso de los senderos nuevos. Los patrones espaciales de los efectos alrededor de nódulos concentrados de uso fueron determinados por un muestreo estratificado alrededor y en sitios lejanos de las señales interpretativas de cada sendero. A pesar de los niveles significativamente bajos de uso (∼15 buceadores libres/sendero/semana), los buceadores libres causaron un daño significativo a los corales a lo largo de los senderos. Los corales ramificados (spp. de corales que no pertenecen a Acropora o Millepora) fueron los más afectados. Se observó más daño cerca de las señales interpretativas que en cualquier otra parte del sendero. Los números de ramas rotas y de colonias de coral dañadas en los senderos se incrementaron rápidamente, pero se estabilizaron a los dos meses de haber iniciado el uso de los senderos. No hubo un cambio significativo dentro de los senderos después de seis meses de uso. A pesar de que la concentración de buceadores libres dentro de senderos confinados incrementó el daño a los corales, los efectos pueden ser mitigados mediante el diseño y la ubicación apropiada de los senderos y mediante el manejo de la conducta de los buceadores libres. La información interpretativa debería prevenir a los usuarios sobre el daño que ellos mismos pueden ocasionar cuando nadan en estos senderos. El manejo de la conducta de los buceadores libres en el agua probablemente sea más efectivo en la reducción del daño que la simple aplicación de límites fijos a la cantidad de uso que un sendero puede recibir.