Minimizing the echo time in diffusion imaging using spiral readouts and a head gradient system.

Purpose: Diffusion weighted imaging (DWI) is commonly limited by low signal-to-noise ratio (SNR) as well as motion artifacts. To address this limitation, a method that allows to maximize the achievable signal yield and increase the resolution in motion robust single-shot DWI is presented.

Methods: DWI was performed on a 3T scanner equipped with a recently developed gradient insert (gradient strength: 200 mT/m, slew rate: 600 T/m/s).

Echo-planar imaging of the human head with 100 mT/m gradients and high-order modeling of eddy current fields.

Purpose: To demonstrate the utility of a high-performance gradient insert for ultrafast MRI of the human head.

Methods: EPI was used for the first time with a readout gradient amplitude of 100 mT/m, 1200 T/m/s slew rate, and nearly 1 MHz signal bandwidth for human head scanning. To avoid artefacts due to eddy currents, the magnetic field was dynamically monitored with NMR probes at multiple points, modeled by solid harmonics up to fifth order, and included in the image reconstruction.