Mild hypoxic-ischemic injury in the neonatal rat brain: longitudinal evaluation of the white matter using diffusion tensor MR imaging

Session 75: Perfusion & Diffusion: Animal Models - Oral presentationWe evaluated longitudinally mild hypoxic-ischemic (HI) induced white matter (WM) damage in a neonatal rat model using DTI and correlated the DTI indices with histological evaluations. Results showed significantly decreased FA and increased ¦Ë¡Í in the injured WM reflected dysmyelination. The longitudinal changes of increasing FA, decreasing ¦Ë¡Í, and no change in ¦Ë// in both injured and control WM suggests continued myelination. Furthermore, differences in FA and ¦Ë¡Í between injured and control WM decreased longitudinally. Our results demonstrated that mild HI induced WM damage continues to mature with partial recovery post-HI, and this could be reflected by DTI in vivo.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 74

Mild hypoxic-ischemic injury in the neonatal rat brain: longitudinal evaluation of the white matter using diffusion tensor MR imaging

Session 75: Perfusion & Diffusion: Animal Models - Oral presentationWe evaluated longitudinally mild hypoxic-ischemic (HI) induced white matter (WM) damage in a neonatal rat model using DTI and correlated the DTI indices with histological evaluations. Results showed significantly decreased FA and increased ¦Ë¡Í in the injured WM reflected dysmyelination. The longitudinal changes of increasing FA, decreasing ¦Ë¡Í, and no change in ¦Ë// in both injured and control WM suggests continued myelination. Furthermore, differences in FA and ¦Ë¡Í between injured and control WM decreased longitudinally. Our results demonstrated that mild HI induced WM damage continues to mature with partial recovery post-HI, and this could be reflected by DTI in vivo.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 74

MEMRI study neonatal hypoxic-ischemic injury in the late stage

Session 16: Manganese Enhanced MRI: Methods & Applications - Oral presentationIn this study, in vivo MEMRI was employed to investigate the hypoxic-ischemic injury in the late phase. Mn2+ induced signal changes were examined using SPM coregistration and ROI analysis. T1WIs SI increase was detected in the perilesional region 24 hours after Mn2+ administration and it colocalized with the increase in glial cell density in GFAP staining, demonstrating the existence of reactive gliosis in the late phase after H-I injury.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 15

In vivo assessment of hepatic ischemia/reperfusion injury in rat using diffusion tensor imaging

Session 12: Advances in Hepatobiliary Imaging - Oral presentationHepatic ischemia/reperfusion injury (IRI) occurs during liver transplantation, tumor resection, hemorrhagic shock and veno-occlusive disease, and is a major cause of acute liver failure. IRI in liver is also responsible for early organ failure and increased incidence of both acute and chronic rejection after liver transplantation. This study aims to examine the changes of diffusion measurements by diffusion tensor imaging (DTI). The experimental results demonstrated that DTI is useful in identifying hepatic IRI by characterizing the transient changes in mean diffusivity and fractional anisotropy.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 11

Identifying rodent olfactory bulb structures with micro-DTI

Conference Theme: Personalized Healthcare Through TechnologyOlfactory bulb (OB) is one of the most developed systems in rodent models with complex neuronal organization and anatomical structures. MR diffusion tensor imaging (DTI) is a non-invasive technique to probe tissue microstructures by examining the diffusion characteristics of water molecules. This paper presents how different OB layers can be identified and quantitatively characterized by micro-DTI using a specially constructed micro-imaging radio frequency (RF) coil. High spatial resolution and high signal to noise ratio (SNR) DTI images of ex vivo rat OBs were obtained. Distinct contrasts were observed between various olfactory bulb layers in trace map, fractional anisotropy (FA) map and FA color map, all in consistence with the known OB neuroanatomy. These experimental results demonstrate the utility of micro-DTI in investigation of complex OB organization. © 2008 IEEE.published_or_final_versio

Early detection of neurodegeneration in brain ischemia by manganese-enhanced MRI

This study aims to employ in vivo manganese-enhanced MRI (MEMRI) to detect neurodegenerative changes in two models of brain ischemia, photothrombotic cortical injury (PCI) and transient middle cerebral artery occlusion (MCAO) in rodents. After systemic Mn 2+ injection to both ischemic models, a close pattern of Tl-weighted hyperintensity was observed throughout different brain regions in comparison to the distribution of GFAP, MnSOD and GS immunoreactivities, whereby conventional MRI could hardly detect such. In addition, the infarct volumes in the posterior parts of the brain had significantly reduced after Mn 2+ injection to the MCAO model. It is suggested that exogenous Mn 2+ injection may provide enhanced MEMRI detection of oxidative stress and gliosis early after brain ischemia. Manganese may also mediate infarctions at remote brain regions in transient focal cerebral ischemia before delayed secondary damage takes place. © 2008 IEEE.published_or_final_versionThe 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBS) 2008, Vancouver, BC., 20-25 August 2008. in Proceedings of the 30th EMBS, 2008, p. 3884-388

Accessible High-Throughput Virtual Screening Molecular Docking Software for Students and Educators

We survey low cost high-throughput virtual screening (HTVS) computer programs for instructors who wish to demonstrate molecular docking in their courses. Since HTVS programs are a useful adjunct to the time consuming and expensive wet bench experiments necessary to discover new drug therapies, the topic of molecular docking is core to the instruction of biochemistry and molecular biology. The availability of HTVS programs coupled with decreasing costs and advances in computer hardware have made computational approaches to drug discovery possible at institutional and non-profit budgets. This paper focuses on HTVS programs with graphical user interfaces (GUIs) that use either DOCK or AutoDock for the prediction of DockoMatic, PyRx, DockingServer, and MOLA since their utility has been proven by the research community, they are free or affordable, and the programs operate on a range of computer platforms

MRI monitoring of ultrasound-targeted microbubbles destruction

Ultrasound-targeted Microbubble Destruction (UTMD) has been used to deliver genes or drugs to specific tissues utilizing microbubbles cavitation and sonoporation effect through guidance of ultrasound imaging. However, ultrasound imaging cannot visualize soft tissues adequately and non-site-specific therapeutic effect may result from the imaging ultrasound irradiation. MRI would be the most effective imaging modality to guide UTMD for genes or drugs delivery due to its better soft tissue delineation without interaction with microbubbles. In this study, we demonstrate that MRI can detect microbubble cavitation and MRI monitoring of UTMD is feasible

MR study of postnatal development of left ventricular myocardium structure and function in rats

Development of heart is known to be essential for all organs growth. Numerous studies have been performed to investigate the growth of cardiac myocytes during postnatal period. However, development of myocardial fiber structure, which plays key role in cardiac function, remains to be explored. In current study, CMR and DTI study were performed to examine the myocardium structural maturation concurrent with the cardiac function development in postnatal rats. The results reveal that significant changes in myocardial fiber quality and helical structure mostly occur during the first 28 days. Furthermore, DTI analysis provides a potentially valuable tool to assess the microscopic changes in cellular morphology in heart

Relation of myocardial fiber structure with cardiac wall motion using DTI and MR tagging

LV structure is known to be associated with cardiac function, but the relation of myocardial fiber distribution with regional wall motion remains to be elucidated. In this study, both tagging and DTI were performed in adult rats. LV myocardium twist, circumferential strain, and myocardial fiber architecture were investigated. Results show that the myocardial fiber distribution has direct relation with the LV myocardium twist angle and magnitude of circumferential strain. Such integrated functional and structural analysis may provide more information for understanding the fundamental cardiac mechanics and assessment of pathological changes