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Artifact reduction techniques infMRI, spiral imaging, and spectroscopic imaging.

機譯：偽影減少技術(shù)包括infMRI，螺旋成像和光譜成像。

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Susceptibility artifacts, subject motion, and partial volume effects are a major cause of artifacts in Magnetic Resonance Imaging (MRI). Various areas of the human head contain air pockets, such as the nasal cavity and the ear canals. This work describes a method to reduce the signal loss in these areas in T2* weighted BOLD imaging, using a single shot z-shim sequence called Z-SAGA.; Also, motion during MRI acquisitions can be a major introduction of artifacts in MR images. When the images can be acquired in a single shot, the final images can be registered for motion related effects. In many instances, single shot acquisitions are not practical, which necessitates a segmented acquisition, such as segmented EPI and interleaved spiral scanning. This work shows how variable density segmented spirals can be used to characterize and correct inter-segment motion for high-resolution spiral MRI.; Regional estimates of metabolite signals from in vivo brain Spectroscopic Imaging (SI) is hindered by partial volume effects. Due to the large voxel size used in SI, each spectroscopic signal contains a contribution from several tissues. This problem is solved by incorporating segmented high-resolution anatomic images into the reconstruction of the SI data, resulting in tissue specific compartmental spectra. Results of this study include the criteria for a newly defined voxel's ability to reconstruct a reliable, free induction decay, and consequently an NMR spectrum. Application of the method for studying regional variations in human brain metabolites is described.
機譯：磁化偽影，對象運動和部分體積效應(yīng)是磁共振成像（MRI）中偽影的主要原因。人頭的各個區(qū)域都有氣袋，例如鼻腔和耳道。這項工作描述了一種方法，該方法使用稱為Z-SAGA的單發(fā)z勻場序列來減少T2 *加權(quán)BOLD成像中這些區(qū)域的信號損耗。同樣，MRI采集過程中的運動可能是MR圖像中偽影的主要引入。當(dāng)可以單次拍攝圖像時，可以注冊最終圖像以獲得與運動相關(guān)的效果。在許多情況下，單次采集是不實際的，這需要分段采集，例如分段EPI和交錯螺旋掃描。這項工作表明如何使用可變密度分段螺旋來表征和校正高分辨率螺旋MRI的節(jié)間運動。來自體內(nèi)腦光譜成像（SI）的代謝物信號的區(qū)域估計受到部分體積效應(yīng)的阻礙。由于SI中使用的大體素大小，每個光譜信號都包含來自多個組織的貢獻。通過將分割的高分辨率解剖圖像合并到SI數(shù)據(jù)的重建中解決了此問題，從而獲得了組織特定的室譜。這項研究的結(jié)果包括新定義的體素重建可靠的自由感應(yīng)衰減的能力的標(biāo)準(zhǔn)，并因此得出了NMR光譜。描述了該方法在研究人腦代謝產(chǎn)物區(qū)域變異中的應(yīng)用。

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