To investigate the propagation of meteorological droughts to agricultural and hydrological droughts, the relationship between droughts was analyzed using observed precipitation and agricultural reservoir and dam storage levels with SPI from 1998 to 2015 in South Korea. For the relationship between different types of droughts, we find that the occurrence of meteorological droughts after concentrated precipitation in the wet season (from June to September) tends not to lead to agricultural or hydrological droughts. A lack of precipitation from April to September, when large volumes of irrigation water are consumed, triggers both meteorological and agricultural droughts. In the case of hydrological droughts propagated from meteorological droughts, precipitation deficits in the dry season (between October and March) caused decrease in dam storage levels only. The occurrence of all different types of droughts is associated with extreme meteorological droughts, which are mainly caused by precipitation deficits in the wet season or prolonged rainfall shortages; in these cases, meteorological droughts led to agricultural and hydrological droughts. An analysis of the seasonal characteristics of storage level changes that in the wet season, agricultural reservoir storage levels are more dependent on precipitation deficits than dam storage levels. On other hand, when precipitation deficits were recorded in the dry season, agricultural reservoir storage levels went up, but dam storage levels dropped. The propagation of meteorological droughts to agricultural and hydrological droughts depends not only on drought severity but also on the drought timing. These findings may contribute to establishing a comprehensive drought monitoring system.

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1289-1297.

OBJECTIVEThe safety of the stent-assisted coil embolization (SAC) technique for acutely ruptured aneurysms has not been established yet. SAC is believed to be associated with a high risk of thromboembolic and hemorrhagic complications in acute subarachnoid hemorrhage (SAH). The aim of this study was to evaluate the safety and efficacy of the SAC technique in the setting of acutely ruptured aneurysm.METHODSA total of 102 patients who received endovascular treatment for acute SAH between January 2011 and December 2017 were enrolled. The SAC technique was performed in 38 of these patients, whereas the no-stent coil embolization (NSC) technique was performed in 64. The safety and efficacy of the SAC technique in acute SAH was evaluated as compared with the NSC technique by retrospective analysis of radiological and clinical outcomes.RESULTSThere were no significant differences in clinical or angiographic outcomes between the SAC and NSC techniques in patients with acute SAH. The rate of ventriculostomy-related hemorrhagic complications was higher in the SAC group than that in the NSC group (63.6% vs 12.5%; OR 12.25, 95% CI 1.78–83.94, p = 0.01). However, all these complications were asymptomatic and so small that they were only able to be diagnosed with imaging.CONCLUSIONSRuptured wide-necked aneurysms could be effectively and safely treated with the SAC technique, which showed clinical and angiographic outcomes similar to those of the NSC technique. Hence, the SAC technique with dual-antiplatelet drugs may be a viable option even in acute SAH.

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