Assessment of mulibrey nanism cardiopathy with functional magnetic resonance imaging

4. Conclusions It has been proposed that thickened pericardium is the main cause of the cardiac malfunction in Mulibrey nanism cardiopathy. In contrary, we showed that the pericardial thickness was normal in all our patients. Diastolic 1/3 filling was rapid, but in normal limits when taking into account the young age of our patient population. Although, LV time volume curves did not show remarkable pathologic changes, a restrictive physiology cannot be definitively excluded. LV end diastolic volumes and cardiac output were clearly reduced in our patients. It could be possible that in the course of time the reduced cardiac output affects clinical pattern of heart failure despite of normal systolic function. The reduced LA largest volume and atrial cyclic volume change may partly contribute to the low cardiac output observed in our patients.     

Functional and metabolic consequences of aortic valve replacement

4. Conclusions Severe aortic valve stenosis leads to a decreased myocardial PCr/ATP, and to impairment of LV diastolic function. Following aortic valve replacement, myocardial PCr/ATP normalizes completely, whereas LV diastolic function improves significantly. Moreover, there is an association between altered myocardial HEP metabolism and impaired LV diastolic function.     

双窗K空间权重导航技术在3.0T磁共振冠脉成像中的应用

提出了一种新的K空间权重导航技术(DKWN),该技术有利于缩短磁共振冠脉成像扫描时间同时获得好的图像质量.并将该导航技术应用到25位健康志愿者.经过实验分析,相比于常规固定窗导航技术而言,DKWN可以使导航效率提高30%(P＜0.05),同时平均扫描时间由2.12 min缩短至1.64 min(P＜0.05),并且图像质量相当.冠脉的直径和长度没有显著差异.     

Accelerating Advanced MRI Reconstructions on GPUs

Computational acceleration on graphics processing units (GPUs) can make advanced magnetic resonance imaging (MRI) reconstruction algorithms attractive in clinical settings, thereby improving the quality of MR images across a broad spectrum of applications. This paper describes the acceleration of such an algorithm on NVIDIA's Quadro FX 5600. The reconstruction of a 3D image with 128(3) voxels achieves up to 180 GFLOPS and requires just over one minute on the Quadro, while reconstruction on a quad-core CPU is twenty-one times slower. Furthermore, relative to the true image, the error exhibited by the advanced reconstruction is only 12%, while conventional reconstruction techniques incur error of 42%.     

Applications of in situ magnetic resonance techniques in chemical reaction engineering

NMR spectroscopy is now a well‐established technique for the in situ study of surface chemistry and the chemical processes occurring during catalytic reactions. Developments in probe design are making the sample environments ever closer to the operating conditions of the catalyst in industrial use. In parallel with these advances there is an increasing interest in the application of field gradient magnetic resonance techniques, namely pulsed gradient spin echo (PGSE) NMR and magnetic resonance imaging (MRI), to in situ studies of mass transport processes in catalysts and reactors. An overview of the recent developments in in situ NMR spectroscopy, PGSE NMR and MRI studies in application to catalysis and reaction engineering is presented and the potential of these techniques in the numerical modelling of catalytic processes and reactor design is highlighted. This revised version was published online in August 2006 with corrections to the Cover Date.     

冻融后花岗岩孔隙发育特征与单轴抗压强度的关联分析

为了研究冻融后岩石的孔隙特征与力学性质之间的关系,对冻融后的花岗岩进行了核磁共振测试和力学试验,分别分析了NMR孔隙度和谱面积与单轴抗压强度之间的关系,并将岩石核磁共振成像结果与力学破坏特性进行了关联分析。研究结果表明：孔隙的发育程度对岩石的力学损伤有重要的影响,岩石的NMR孔隙度和谱面积与单轴抗压强度之间的关系式均为指数分布,岩石内部的孔隙分布情况与其力学性质和宏观破坏特征之间存在一定的联系;采用分形理论对冻融后花岗岩的孔隙发育特征进行了描述,得出了冻融花岗岩孔隙发育的分形维数。分析表明,冻融作用下岩体内的裂隙产生及其演化具有自相似性,分形维数值越大,孔隙越发育,其单轴抗压强度就越小。     

SIMULTANEOUS HEAT AND MOISTURE TRANSFER IN CHEDDAR CHEESE DURING COOLING. II. MRI TEMPERATURE MAPPING

ABSTRACT

Non-destructive Magnetic Resonance Imaging (MRI) techniques were developed to monitor simultaneous heat and moisture transfer in cheese cooling. The FLASH imaging sequence was used to achieve fast data acquisition for temperature images. MRI results of temperature distributions in cheese blocks during cooing are very closed to those from numerical simulation.     

Reflections on blindsight: Neuroimaging and behavioural explorations clarify a case of reversed localisation in the blind field of a patient with hemianopia.

Blindsight refers to residual visual abilities of patients with primary visual cortex lesions. Most of this research uses single case studies, most famously patient GY. We examined a patient (DC) after surgical resection of V1 who demonstrated robust but reversed blind field target localisation, mislocalising midline blind field targets to the periphery and vice versa. This pattern was reliable across multiple sessions and was not because of extraocular light scatter. We then used functional magnetic resonance imaging to examine neural responses to blind field motion stimuli with no evidence of motion-selective activation in DC's extrastriate cortex in the damaged hemisphere, in stark contrast to GY who showed robust bilateral activation in response to blind field stimuli. This suggests that DC's blind field performance may not represent true blindsight. Follow-up testing with the target—background contrast reversed (i.e., black targets/white background), eliminated DC's reversed localisation, strongly suggesting that she was employing an unusual decision criterion based on intraocular light scatter. DC's failure to demonstrate true blindsight may be related to the age at which she acquired her lesion—much later in life than GY. (PsycINFO Database Record (c) 2010 APA, all rights reserved)