Radiology
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To compare quantitative cerebral blood flow (CBF) values in patients with Alzheimer disease (AD), patients with mild cognitive impairment (MCI), and subjects with subjective complaints by using a whole-brain three-dimensional (3D) pseudocontinuous arterial spin-labeling (ASL) technique at 3.0 T. ⋯ CBF measured with 3D pseudocontinuous ASL MR imaging helps detect functional changes in the prodromal and more advanced stages of AD and is a marker for disease severity.
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Instruments that combine positron emission tomography (PET) and magnetic resonance (MR) imaging have recently been assembled for use in humans, and may have diagnostic performance superior to that of PET/computed tomography (CT) for particular clinical and research applications. MR imaging has major strengths compared with CT, including superior soft-tissue contrast resolution, multiplanar image acquisition, and functional imaging capability through specialized techniques such as diffusion-tensor imaging, diffusion-weighted (DW) imaging, functional MR imaging, MR elastography, MR spectroscopy, perfusion-weighted imaging, MR imaging with very short echo times, and the availability of some targeted MR imaging contrast agents. Furthermore, the lack of ionizing radiation from MR imaging is highly appealing, particularly when pediatric, young adult, or pregnant patients are to be imaged, and the safety profile of MR imaging contrast agents compares very favorably with iodinated CT contrast agents. MR imaging also can be used to guide PET image reconstruction, partial volume correction, and motion compensation for more accurate disease quantification and can improve anatomic localization of sites of radiotracer uptake, improve diagnostic performance, and provide for comprehensive regional and global structural, functional, and molecular assessment of various clinical disorders. In this review, we discuss the historical development, software-based registration, instrumentation and design, quantification issues, potential clinical applications, potential clinical roles of image segmentation and global disease assessment, and challenges related to PET/MR imaging. ⋯ http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121038/-/DC1.
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To determine the energy levels that provide optimal imaging of thoracic circulation at dual-energy computed tomographic (CT) angiography with reduced iodine load in comparison with a standard technique. ⋯ http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120195/-/DC1.
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To evaluate whether quantitative diffusion-tensor tractography can show abnormalities in long association tracts of subjects with symptoms after traumatic brain injury without any visible signs of intracranial or intraparenchymal abnormalities of obvious traumatic origin at routine magnetic resonance (MR) imaging and to determine the number and type of these abnormalities. ⋯ http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112570/-/DC1.
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To (a) use a new second-generation wide-volume 320-detector row computed tomographic (CT) scanner to explore optimization of radiation exposure in coronary CT angiography in an unselected and consecutive cohort of patients referred for clinical purposes and (b) compare estimated radiation exposure and image quality with that from a cohort of similar patients who underwent imaging with a previous first-generation CT system. ⋯ http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122621/-/DC1.