The use of cerebral blood volume (CBV) maps generated from dynamic MRI studies tracking the bolus passage of paramagnetic contrast agents strongly depends on the signal-to-noise ratio (SNR) of the maps. The authors present a semianalytic model for the noise in CBV maps and introduce analytic and Monte Carlo techniques for determining the effect of experimental parameters and processing strategi...

The introduction of the ultrafast imaging sequences has renewed the interest in development of RF coils. The theoretical frame of the SNR of MRI coils is a challenge because it requires a deep mathematical background to master the associated concepts. Here, a simpler method is proposed based on Legendre polynomials. This approximation method, together with a quasi-static approach, was used to d...

Destructive interference from phase fluctuations caused by motion during (1)H magnetic resonance spectroscopy (MRS) stimulated-echo acquisition mode (STEAM) and point-resolved spectroscopy (PRESS) acquisitions can significantly diminish the traditional radicalN-gain in signal-to-noise ratio (SNR) afforded by averaging N signals, especially in the torso. The SNR loss is highly variable among ind...

The performance of uplink multiuser MIMO (MU-MIMO) transmissions heavily depends on which users to transmit together. InWLANs where each user independently determines when to transmit by random access, the performance degradation occurs when a set of users for concurrent transmissions are not chosen properly. In this paper, we address this problem and propose SNR-MAC protocol to enhance the upl...

We estimate the fundamental limits of different microrheological techniques based on optical detection. It is suggested that particle tracking systems using nondifferential detection have a minimum detectable displacement given by 0.2(lambda0/NA)(1/square root of (SNR)), where lambda0 is the wavelength, NA is the numerical aperture of the focusing objective, and SNR is the signal-to-noise ratio...

The supernova remnant (SNR), Ho 12, in the center of the dwarf irregular galaxy NGC 6822 was previously observed at X-ray, optical, and radio wavelengths. By using archival Chandra and ground-based optical data, we found that the SNR is spatially resolved in X-rays and optical. In addition, we obtained a ∼ 5 resolution radio image of the SNR. These observations provide the highest spatial resol...