نتایج جستجو برای: mr coils
تعداد نتایج: 72172 فیلتر نتایج به سال:
MR microneurography is a noninvasive technique that provides visualization of the microanatomy of peripheral nerves, otherwise available only with histopathology. The objective of this study was to present a protocol to visualize the microstructure of peripheral nerves in vivo, using a 3T MRI scanner with a clinical set of coils and sequences. The tibial and the common peroneal nerves of health...
Image bias is a usual phenomenon in MR imaging when using surface coils. It complicates the interpretation as well as the algorithmic postprocessing of such data. We introduce a bias correction algorithm based on homomorphic unsharp masking (HUM) that is applicable on a broad range of image types (as long as foreand background is separable), simple, fast and requires only minimal user interacti...
Use of a surface coil in MR imaging increases signal-tonoise ratio and improves image quality. The technique is used primarily for making a detailed examination of a specific anatomic region or a localized disease process. We describe a transport system that can be used with flat surface coils for examining extended regions of the body. The device is particularly useful for evaluating the verte...
Following PET/CT and SPECT/CT, PET/MR hybrid imaging is the most recent addition to the palette of hybrid cardiac imaging modalities. PET/MR synergistically combines the excellent soft tissue contrast and detailed image resolution of MR with metabolic information provided by PET. Integrated PET/MR systems furthermore offer the ability to acquire hybrid imaging data simultaneously (1). Beyond ex...
The birdcage (BC) coil is currently being utilized for uniform radiofrequency (RF) transmit/receive (Tx/Rx) or Tx-only configuration in many magnetic resonance (MR) imaging applications, but insufficient magnetic flux (|B1|) density and their non-uniform distribution still exists in high-field (HF) environments. We demonstrate that the asymmetric birdcage (ABC) transmit/receive (Tx/Rx) volume c...
Hyperpolarized 13C magnetic resonance (MR) is a promising technique for the noninvasive assessment of regional cardiac metabolism since it permits heart physiology studies in pig and mouse models. The main objective present study to resume work carried out at our electromagnetic laboratory field radio frequency (RF) coil design, building, testing. In this paper, first, we review principles RF c...
An analytically exact method is proposed to extract the signal intensity and the noise variance simultaneously from noisy magnitude MR signals. This method relies on a fixed point formula of signal-to-noise ratio (SNR) and a correction factor. The correction factor, which is a function of SNR, establishes a fundamental link between the variance of the magnitude MR signal and the variance of the...
Magnetic resonance (MR) is used more and more frequently to diagnose changes in the musculoskeletal system in the course of rheumatic diseases, at their initial assessment, for treatment monitoring and for identification of complications. The article presents the history of magnetic resonance imaging, the basic principles underlying its operation as well as types of magnets, coils and MRI proto...
Simultaneous acquisition of spatial harmonics (SMASH): fast imaging with radiofrequency coil arrays.
SiMultaneous Acquisition of Spatial Harmonics (SMASH) is a new fast-imaging technique that increases MR image acquisition speed by an integer factor over existing fast-imaging methods, without significant sacrifices in spatial resolution or signal-to-noise ratio. Image acquisition time is reduced by exploiting spatial information inherent in the geometry of a surface coil array to substitute fo...
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