Matlab's Shepp-Logan phantom (The Mathworks) of 5 mm in-plane resolution with a matrix size of N x M = 64 x 64 pixels and a unit 37.5 nT/m linear [B.sup.+.sub.1] field gradient within the imaging region produced by the single-channel RF coil of the RRFC transmit system rotating about the phantom at a frequency of [[omega].sub.rot] = 1256 rad [s.sup.-1].
To obtain realistic sensitivity maps and k-space data for the purpose of this study, we employed a previously constructed rotating RF coil (RRFC) apparatus for head imaging, as shown in Figure 1.
Both methods work equally well, and in this study we used the latter approach in four independent imaging experiments by fixing the RRFC coil at angular positions interspaced by 90[degrees] and employing the fast low angle shot (FLASH) imaging sequence, parameters of which are given in Figure 7.
While rotating the RF coil (RRFC) provides a large number of DOF in form of [B.sup.+.sub.1] gradients (RF sensitivity profiles) over time, the SNR could be further enhanced by applying a train of 180[degrees] RF refocusing pulses to refocus any decoherence in the spin magnetization.
Beside standard and spectroscopic MR imaging applications, the RRFC approach with [B.sup.+.sub.1] gradients may be suitable for imaging sequences such as nuclear quadrupole resonance (NQR) , motion detection methods, echo planar rotating frame imaging (EPROFI) , ultrashort echo time (UTE) acquisition , and transmit array spatial encoding (TRASE) technique .
Repeated readings to a fluency criterion (RRFC) condition involved the participant reading the targeted passage for one minute twice.
The experimenter used an alternating treatments design (Kennedy, 2005) to evaluate the effects of the IS and RRFC conditions.
Prior to the start of the first session of each phase, the experimenter randomly chose one of the passages for the IS condition and one of the passages for the RRFC condition.
Why or why not, (b) Which reading procedure did you like better, 1 minute (i.e., RRFC) or 10 seconds (i.e., IS)?
The solid black dots represent correctly read words and the solid black squares represent incorrectly read words for each assessment passage of the repeated reading to a fluency criterion (RRFC) condition.
Meeting criterion first under the RRFC condition, Brad read 229 correct with 2 errors during the 13th session.