A four‐channel time domain multiplexer: A cost‐effective alternative to multiple receivers

Abstract

The concept of simultaneous image acquisition as originally conceived by Hyde has been implemented by Roemer et al. using a multiple receiver system. This article describes an alternative technique that uses time domain multiplexing (TDM) to acquire simultaneous images using a single receiver channel. This method requires few modifications to the existing receiver and has been shown to be equivalent to a true four channel receiver in most applications. The multiplexing technique was implemented and tested on a standard commercial scanner that has also been equipped with a four channel receiver. Signal-to-noise results demonstrate that four independent images can be multiplexed through a single receiver channel with no degradation in image quality. Additionally, spine images that were obtained from a normal volunteer with both a multiplexed single channel receiver and a true four channel receiver system are presented.

Theory and application of array coils in MR spectroscopy

“…The signals are independently demodulated and digitized, using either multiple receiver channels 6,28 or timedomain multiplexing. [40][41][42] The general problem at hand is to determine the set of weighting functions [w] that optimize the signal-to-noise ratio obtained from the array. These weighting functions will be different for each voxel in the image or spectroscopic image.…”

Optically detunable, inductively coupled coil for self‐gating in small animal magnetic resonance imaging

“…The combination of a cardiac coil and a whole body coil usually requires additional receiver channels. This is not the case if data multiplexing is used where the coil elements are switched on and off subsequently, and the signal is routed to one receiver channel only (9). Multiplexing can be employed if for example not all coils are necessary for all data acquisitions (10).…”

Simulation‐based investigation of partially parallel imaging with a linear array at high accelerations

“…[12] and [13] can be rearranged to illustrate that the expected artifact power is also a function of relative SNR values. The SNR provided by coil i at aliasing location j is defined as:…”

“…The number of channels available on commercial clinical MRI systems has increased significantly in the last decade and clinical phased arrays are now standard issue. Additionally, specialized hardware can be used to extend the number of available channels on virtually any console system (13,14), which can then be used for increasing the potential of partially parallel techniques (15). The combination of these factors implies that the number of available receivers, or the number of available array elements, is not likely to remain the ultimate fundamental limitation in the presence of other experimental complications.…”