Adw 4.6 workstation

The clinical test was performed using a GE discovery MR750 3.0T magnetic resonance scanner and 8-channel head-neck combined coils. The 3D-pcASL sequences were collected only once. The PLD values were preset at 1025 ms for the 0- to <24-hour-old groups (HIE/control) and 1- to <3-day-old groups (HIE/control) and 1525 ms for all other groups (HIE/control). The other scanning parameters in the clinical test were the same as those of the clinical pretest.
Data analysis: (1) Raw data were imported into the Functool software through the GE ADW 4.6 workstation; then, the CBF maps were obtained. (2) The CBF values in the regions of brain, such as the cerebellum, thalamus, occipital lobe, temporal lobe, parietal lobe and frontal lobe, were detected. (3) The round regions of interest (ROIs) with sizes of (55±2) mm² were manually delineated, and the sizes, locations and levels of the ROIs were kept as consistent as possible in all cases; we tried to select the gray matter region during the selection of ROIs because in neonates with HIE, gray matter is more prone to ischemia due to hypoxia. We chose the ROIs to avoid the large blood vessel areas of the brain as much as possible[27 (link)–29 (link)] (Fig 1A–1C).

Image post-processing and reconstruction were accomplished on the GE ADW4.6 workstation using maximum intensity projection, multi-planar reformation and volume rendering techniques.

For in vitro MR relaxation text, GPT NPs and Omniscan were diluted in Eppendorf tubes (2 mL volume) at various Gd concentration (0.006–0.1 mM) concentrations. T₁ map sequence: repetition time (TR) = 1000, 2000, 3000, 4000 ms; echo time (TE) = 8 ms; slice thickness = 2 mm; space = 0.5 mm; field of view (FOV) = 18; phase FOV = 0.8; freq × phase = 256 × 192; number excitations (NEX) = 2; echo train length (ETL) = 3. MR images were transferred to ADW 4.6 workstation (GE Healthcare, US). The mean T₁ values of each sample were measured by regions-of-interest (ROI) on the T₁-mapping post-processing software and the relaxation rate r₁ was determined according to the linear plot of 1/T₁ versus Gd concentration.

Routine MRI and ¹H‐MRS were performed with a 3‐T MRI system (Sigma HDx Twin speed, General Electric Medical Systems) with a standard 8‐channel head coil. Two associate chief physicians interpreted all images.
The MRI parameters were: repetition time (TR), 4,420.0 ms; echo time (TE), 112.1 ms; matrix, 512 × 512; slice thickness, 5.0 mm; interlayer thickness, 1.0 mm.
Multi‐voxel ¹H‐MRS were performed using a point‐resolved spectroscopy sequence with the following parameters: TR, 1,500 ms; TE, 35 ms; phase × frequency = 18 × 18, volume of interest, 8 × 10 × 1 cm; field of view, 240 × 240 mm; and number of excitations = 1.
Water suppression (>95%) and shimming (linewidth, <12 Hz) were automatically achieved using a variable pulse power and optimized relaxation delay scheme. After zero‐filling and baseline correction, the spectra were post‐processed automatically using “Advantage Window 4.6 workstation Functool software” (General Electric Medical Systems Signa excite 3.0T HD Ecospeed MRI, ADW 4.6 workstation, USA). The peak areas were the proportion using creatine as the reference which represent the various metabolic concentration such as NAA/Cr and Cho/Cr. The regions of interest (ROIs) for spectral analysis included the substantia nigra, globus pallidus, prefrontal lobe, hippocampus, cuneus gyrus and dorsal thalamus on both sides of the brain (Figure 1).