Functool

The liver MR imaging was performed using a 3.0 T MR imager (Signa VH3, GE HealthCare) and a Mayo Clinic BC-10 MRI coil. After anesthesia, the rat was placed in a supine position in a plastic holder. The imaging parameters are described in Table 1. The axial liver MR imaging included free-breathing precontrast T1- and T2-weighted, DW imaging (b = 0 and b = 800 sec/mm², with motion-sensitive gradients applied in three orthogonal directions to minimize the effects of diffusion anisotropy), and contrast-enhanced T1-weighted imaging (0.1 mmol/kg, Magnevist, Bayer-Schering). The HCC assessments were performed on a workstation (AW4.2; GE Healthcare) by the consensus of two experienced radiologists. The contours of the entire tumor on the enhanced T1-weighted images were manually drawn as regions of interest (ROIs), and the whole-tumor volume was determined. The ADC maps were generated using built-in software (Functool; GE Healthcare). The ROIs for whole-tumor volume measurement were also used for the ADC measurements. The day 10/baseline (D₁₀/baseline) and day 20/baseline (D₂₀/baseline) tumor volume ratios and the D₁₀/baseline and D₂₀/baseline ADC ratios were calculated.

MRI was performed using a 3.0-T GE Signa Echo-Speed MR scanner (GE Medical Systems, Milwaukee, WI, USA). All MRI images in this study were obtained in the afternoon to minimize the diurnal variation of T2 values in the IVDs [24] (link).
Sagittal T1-weighted fast spin echo (FSE) and sagittal, transversal, and axial T2-weighted FSE sequences were used for morphological MRI (for detailed sequence parameters see Table 1). The sagittal T2 weighted images (WIs) were used for visual Pfirrmann grading of IVD degeneration. Next, a T2 map was created using the T2 values in the midsagittal section from sagittal sections centered on the cervical midline region with optimized 8 echo multi-spin echo (Repetition time /first,last time echo time, TR/(fTE, lTE), 1500/8.5, 17.0, 25.5, 34, 42.4, 50.9, 59.4, 67.9, field of view (FOV)  = 20 mm×20 mm, section thickness  = 3.0 mm, matrix  = 256×160, number of signal intensity acquisitions  = 1, and total examination time 4 min and 27 s) obtained using an ADW 4.3 workstation (Functool, GE Medical Systems, Milwaukee WI, USA). However, the first echo from the multi-spin system was excluded to minimize the effect of the stimulated echo [14] (link). A single midline sagittal section was positioned parallel to each cervical IVD from C2–3 to C6–7. The T2 maps were computed in each pixel from the SI in the respective TE using the following formula: SI  = e^−TE/T2.

Using a single-shot spin-echo echo planar image (SE-EPI) sequence, DTI data without diffusion weighting (b = 0) were acquired simultaneously in 25 non-collinear directions (b = 1,000 s/mm2). Moreover, 22 contiguous slices were acquired with a 3 mm slice thickness and with no gap. They were performed using acquisition with a 128 × 128 matrix; and a 256 x 256 mm field of view (FOV). The other acquisition parameters were: repetition time (TR) = 6,000 ms; echo-time (TE) = 76.2 ms; number of excitations (NEX) = 2.
DTI data were processed using the software FuncTool (GE Healthcare). The principal 3D orientation of the major eigenvector was color-coded per voxel. Each diffusion tensor was sampled 6 times to optimize the signal-to-noise ratio (SNR). Isotropic diffusion-weighted, ADC, and fractional anisotropy (FA) maps were generated. By positioning the region of interest (ROI) (33 ± 0.4 mm2) the targeted fibers, we got the FA values of the bilateral arcuate fasciculus (AF), uncinate fasciculus (UF), cingulum bundle (CB), fornix, superior longitudinal fasciculus (SLF) and anterior commissure (AC) as we previously described (30 (link)).