Design and manufacture of an ultra-compact, 1.5 T class, controlled-contact resistance, REBCO, brain imaging MRI magnet.

Brain imaging MRI comprises a significant proportion of MRI scans, but the requirement for including the shoulders in the magnet bore means there is not a significant size reduction in the magnet compared to whole-body magnets. Here we present a new design approach for brain imaging MRI magnets targeting ±20 kHz variation over the imaging volume rather than the more usual ±200 Hz making use of novel high-bandwidth MRI pulse sequences and distortion correction. Using this design approach, we designed and manufactured a 1.

Development of a compact NMR system to measure pO in a tissue-engineered graft.

Cellular macroencapsulation devices, known as tissue engineered grafts (TEGs), enable the transplantation of allogeneic cells without the need for life-long systemic immunosuppression. Islet containing TEGs offer promise as a potential functional cure for type 1 diabetes. Previous research has indicated sustained functionality of implanted islets at high density in a TEG requires external supplementary oxygen delivery and an effective tool to monitor TEG oxygen levels.

Fast spin-echo approach for accelerated B gradient-based MRI.

Purpose: To expand on the previously developed -encoding technique, frequency-modulated Rabi-encoded echoes (FREE), to perform accelerated image acquisition by collecting multiple lines of k-space in an echo train.

Methods: FREE uses adiabatic full-passage pulses and a spatially varying RF field to encode unique spatial information without the use of traditional B gradients. The original implementation relied on acquiring single lines of k-space, leading to long acquisitions.

Correcting image distortions from a nonlinear -gradient field in frequency-modulated Rabi-encoded echoes.

Purpose: To correct image distortions that result from nonlinear spatial variation in the transmit RF field amplitude ( ) when performing spatial encoding with the method called frequency-modulated Rabi encoded echoes (FREE).

Theory And Methods: An algorithm developed to correct image distortion resulting from the use of nonlinear static field (B ) gradients in standard MRI is adapted herein to correct image distortion arising from a nonlinear -gradient field in FREE. From a -map, the algorithm performs linear interpolation and intensity scaling to correct the image.

B -gradient-based MRI using frequency-modulated Rabi-encoded echoes.

Purpose: Reduce expense and increase accessibility of MRI by eliminating pulsed field (B ) gradient hardware.

Methods: A radiofrequency imaging method is described that enables spatial encoding without B gradients. This method, herein referred to as frequency-modulated Rabi-encoded echoes (FREE), utilizes adiabatic full passage pulses and a gradient in the RF field (B ) to produce spatially dependent phase modulation, equivalent to conventional phase encoding.