The images Dinaciclib clinical trial are reconstructed on a 128 × 128 pixel grid corresponding to a resolution of 0.2 mm × 0.2 mm × 1 mm with

a 25 mm FOV. The sequence is run with a two-step phase cycle to eliminate the DC offset and the total acquisition time for the image was 2 min. The second UTE sequence is run using the same parameters, however, only one average with 32 spokes of data is acquired and a 10° tip angle is used to further reduce the acquisition time. The total acquisition time for this sequence was 500 ms. Slice selection was validated using a uniform sample of doped water and the pulse sequence shown in Fig. 3. The slice select gradient was set to 5.1 G cm−1 and the acquisition gradient was set to 11.7 G cm−1. The homospoil pulses were set to 22.0 G cm−1 and had a duration of 1 ms with a 5 ms delay before and after the 180° hard pulse. The SW was set to 106 and 512 complex points were collected. As a comparison for the UTE image, a spin echo image was run for each sample. The spin echo used a TE of CDK inhibitor drugs 3 ms with a resolution of 0.2 mm × 0.2 mm × 1 mm. A 512 μs Gaussian pulse was used for slice selection and the SW was set to 105. The total acquisition time for the image was 4 min. In the following, UTE is first simulated using the Bloch equations to demonstrate

the concept and illustrate the artifacts that commonly arise during slice selection. The gradient optimization and slice selection are then explored. The accuracy of UTE image reconstruction is demonstrated using a challenging sample with a complex three dimensional structure. The benefits of UTE are then shown by imaging two samples, one of cork and one of rubber. Finally, the potential for dynamic imaging is explored using CS. Fig. 4 shows a simulation of the Bloch equations for a typical Gaussian slice selection. A Gaussian r.f. excitation pulse is used with a gradient on for the duration of the r.f. pulse. The gradient is then applied in a negative direction for half of the time of the r.f. pulse with the same magnitude as during the r.f. pulse. The negative gradient acts to rephase the spins that have been dephased during

the second half of the r.f. pulse. The slice selected by this sequence is a Gaussian shape as expected. The slice selection for UTE attempts unless to emulate the shape of the slice selected using this traditional method of slice selection, but using a half Gaussian pulse to reduce TE. Fig. 5 shows the equivalent slice selection performed using UTE. UTE uses a half Gaussian pulse for soft pulse excitation, which eliminates the need for a negative refocusing gradient. However, the half-Gaussian pulse results in the formation of a complex dispersion mode excitation profile. To select a Gaussian slice, the acquisition must be run twice, once with a positive slice select gradient and once with a negative slice select gradient. The imaginary slice profile for these two acquisitions will be in anti-phase, as shown in Fig.