Mr discovery 750

All MR experiments were performed using a 3 Tesla (T) clinical MRI scanner (MR Discovery 750, GE Healthcare, Waukesha, Wisconsin) equipped with broadband amplifiers and a custom-built dual tuned ¹H/¹³C transmit/ receive radiofrequency (RF) volume coil. Animal experiments were performed using a volume insert coil designed to image rats.

MRI was performed in 5 ischemic stroke patients using 3D ASL, 3D mGRE, and DWI on a clinical 3T scanner (GE MR Discovery 750) using a 32-channel brain receiver coil. The time interval between stroke onset and MRI examination ranged between 6 hours and 12 days. All lesions were located in unilateral cerebral artery territory. The 3D FSE ASL sequence parameters were: 24 cm FOV, 1.9 mm in-plane resolution, 2.0mm slice thickness, 1500 ms labeling period, 1525 ms post-label delay, 976.6 Hz/pixel bandwidth, 68 axial slices, TE=14.6 ms, TR=4787 ms, and 3 signal averages. The 3D mGRE sequence parameters were: 0.47mm in-plane resolution, 2mm slice thickness, volume coverage identical to the 3D FSE ASL sequence, 8 equally spaced echoes: TE₁/ΔTE/TE₈ = 4.5/5/39.5 ms, TR= 42.8 ms, bandwidth=244.1 Hz/pixel, and flip angle 20^o. DWI sequence parameters were: 24 cm FOV, 0.94 mm in-plane resolution, 3.2 mm slice thickness, 1953.1 Hz/pixel bandwidth, 0, 1000 s/mm² b-values, TE=71 ms, TR=3000 ms, and 4 signal averages (Supporting Information Table S1b).

This retrospective image analysis was approved by the local institutional review board. Thirty-three ischemic stroke patients all with lesions in unilateral cerebral artery territory were classified into two groups based on the time interval between stroke onset and MRI scan^{50 (link)}: acute (6-24 hours, $N=6$ ) and subacute (1-14 days, $N=27$ ) phase. They underwent MRI on a clinical 3T scanner (GE MR Discovery 750) using (1) 3D FSE ASL (24-cm FOV, 1.9 × 1.9 × 2.0 mm³ voxel size, 1500-ms labeling period, 1525-ms postlabel delay, 976.6-Hz/pixel bandwidth, 68 axial slices, TE = 14.6 ms, TR = 4787 ms, and three signal averages), (2) 3D mGRE (0.47 × 0.47 × 2.0 mm³ voxel size, identical FOV to the 3D FSE ASL sequence, and eight equally spaced echoes: TE₁/ΔTE/TE₈ = 4.5/5/39.5 ms, TR = 42.8 ms, bandwidth = 244.1 Hz/pixel, and flip angle 20°), and (3) DWI (24-cm FOV; 0.94 × 0.94 × 3.2 mm³ voxel size; 1953.1-Hz/pixel bandwidth; 0, 1000 s/mm² b-values; TE = 71 ms; TR = 3000 ms; and four signal averages), and (4) a T₁-weighted fluid attenuated inversion recovery sequence^{51 (link)} (24-cm FOV, 0.5 × 0.5 × 5 mm³ voxel size, TE = 23.4 ms, and TR = 1750 ms).