Abstract

Methods: Experiments were performed on a GE Signa Excite 1.5 T scanner with a custom 8-channel upper airway receiver coil that has four elements on either side of the jaw; the coil was designed to provide high sensitivity over all the important articulators (lips, tongue, epiglottis, velum). A gradient echo based spiral acquisition with golden angle ordering [3] was employed (FOV: 20cm2, FA: 15 degrees, slice thickness: 5mm, TR= 6.004 ms). Single slice sequences with spatial resolutions of 2.5 mm2 and 1.34 mm2 were realized by modifying the number of spiral interleaves required to satisfy Nyquist (R= 1) sampling. An interleaved three-slice sequence at 2.5 mm2 was also realized [4]. In Fig. 1, we demonstrate the spatial and temporal resolution trade-offs with spiral sequences that are designed to make maximum use of gradients (40 mT/m amplitude and 150 mT/m/ms slew rate). As shown in Fig. 1, we propose to realize a reduction factor R~ 6.5. We utilized a sparse SENSE image reconstruction strategy with temporal total variation as the sparsity constraint [5]. The coil maps were estimated from time averaged data using an eigen-decomposition method [6], and the resulting optimization was solved by using a non-linear conjugate gradient algorithm. We chose the regularization parameter empirically. Image data were acquired from a healthy 29 year old adult male speaker during the following stimuli production (a) repetition of phrase:/loo-/lee-/laa-/za-/na-/za (b) counting of numbers: one-two-three-four at normal pace, followed by a rapid pace. Results: In Figures 2, 3, we show the single slice reconstructions when the subject was counting …

Date

2015

Authors

Sajan Goud Lingala, Yinghua Zhu, Yoon-Chul Kim, Asterios Toutios, Shrikanth Narayanan, Krishna S Nayak

Journal

Proc. ISMRM 23rd Scientific Sessions

Pages

p689