1.5t mri scanner

3D T1 weighted anatomical brain MRI scans were collected with a General Electric 1.5T MRI scanner, using a high resolution antenna and a homogenization PURE filter [Fast Spoiled Gradient Echo (FSPGR) sequence with parameters: TR/TE/TI = 11.2/4.2/450 ms; flip angle 12°; 1 mm slice thickness, a 256 × 256 matrix and FOV 25 cm].
FreeSurfer software (version 5.1.0; Fischl et al., 2002 (link)) was used to obtain the hippocampal volumes, which were normalized with the overall intracranial volume (ICV) of each subject.

Fifth- to sixth-passage Fth1-BMSCs cultured in plates with an optimum concentration of ferric ammonium citrate for 24 h were washed with PBS to remove excess ferric ammonium citrate. Fth1-BMSCs (1 × 10⁶ cells) were embedded in 600 μL PBS and 400 μL agarose (1%) uniformly in 1.5 ml cryotubes and kept for 30 min at room temperature (25°C). The positive and blank controls contained 50 μg/ml SPIO-BMSCs and BMSCs, respectively. We chose a series of survey images as observation indices including T2-weighted imaging (T2WI) and susceptibility-weighted imaging (SWI) sequences using a 1.5 T MRI scanner (General Electric, USA). Scanning parameters were as follows: (1) T2WI a with fast spin echo (FSE) sequence, TR/TE = 2250/102 ms, and depth = 12.5 mm. (2) SWI with a SWAN sequence, TR/TE = 82.8/44.7 ms, flip angle = 15°, and depth = 41.67 mm.

This study was approved by the Institutional Review Board of Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan (No. 202002387B0). All methods were carried out in accordance with relevant guidelines and regulations. Both MRI and CT scans of each participant were acquired at Chang Gung Memorial Hospital at LinKou, Taoyuan, Taiwan. Multimodal MRI examinations were performed on a 1.5T MRI scanner (GE, Boston, MA, USA) with a standard head coil. The three-dimensional T1-weighted gradient-echo sequence (MPRAGE) was obtained with repetition time (TR)/echo time (TE)/inversion time (TI)/flip angle (FA) = 7.91 ms/3.27 ms/450 ms/12°; voxel size = 0.39 × 0.39 × 1.0 mm³, and number of average = 2. CT examinations were performed on a GE Light Speed RT16 with a standard brain protocol. Scan parameters were as follows: slice thickness = 1.25 mm of slice thickness, 120 kV of slice thickness, 300 mA of tube current, and 1071 msec of exposure time.

All anatomical and BOLD-sensitive MRI data were acquired using gradient-echo echo-planar imaging (EPI) sequences in a 1.5T MRI scanner (GE) with an eight-channel-phased array head coil. Foam pads were used to reduce head movements and scanner noise. To measure the individual fMRI data, the imaging parameters were set as follows: slice thickness = 5 mm, slice gap = 1 mm, TR = 2,000 ms, TE = 30 ms, FOV = 24 cm × 24 cm, flip angle = 90°, and matrix = 64 × 64. 180 volumes (20 slices per volume) were acquired during 360 s of an fMRI run. During data acquisition, subjects were required to relax with eyes closed, not to fall asleep, and to move as little as possible. For anatomic data sets, we used a 3D-BRAVO sequence (thickness: 1.4 mm (no gap), TR = 8.2 ms, TE = 1.0 ms, FOV = 24 cm × 24 cm, flip angle = 25°, and matrix = 256 × 256).

After four weeks of induction of IDD, each animal was scanned with X-rays and by MRI. X-ray images were obtained using a digital X-ray machine (Shimadzu, Japan) and stored digitally. Using a previously reported method [27 (link)], the disc height index (DHI) was calculated from the mean of measurements obtained from the anterior, middle, and posterior portions of the disc which was divided by the mean height of the adjacent vertebral body using ImageJ image analysis software. Changes in DHI were recorded as %DHI and normalized to the DHI of the preoperative IVD (%DHI = DHI postsurgery/DHI presurgery∗100).
T2 mapping of MRI signal intensity is commonly used to measure the degree of IDD. The procedure was conducted as previously described [28 (link)], in a 1.5T MRI scanner (GE, USA). Briefly, all rats were scanned and the T2 signal intensity of the Co8-9 discs was recorded. The ratio of T2 signal intensity of each injured disc to the control disc was recorded from analysis using ImageJ software. Therefore, normalized IVD intensity had values ranging from 0 to 1.

Three-dimensional T1-weighted anatomical brain magnetic MRI scans were collected with a General Electric 1.5 TMRI scanner, using a high resolution antenna and a homogenization PURE filter (Fast Spoiled Gradient Echo (FSPGR) sequence with parameters: TR/TE/TI = 11.2/4.2/450 ms; flip angle 12°; 1 mm slice thickness, a 256 × 256 matrix and FOV 25 cm). Freesurfer software (version 5.1.0.; Fischl et al., 2002 (link)) was used to obtain the hippocampal volumes, which were normalized with the overall intracranial volume (ICV) of each subject.

At two and four weeks after the needle puncture, all rats underwent X-ray radiography and MRI scans under isoflurane anesthesia. Radiographic images were taken with a digital X-ray machine (SHI- MADZU, Japan), and images were stored in a digital form. Based on the previously reported method [23 (link)], the disc height index (DHI) was calculated by averaging the measurements obtained from the anterior, middle, and posterior portions of the disc height and dividing them by the average height of the adjacent vertebral body using the image analysis program ImageJ. Changes in the DHI (representing the disc space) of IVD were presented as %DHI and normalized to DHI of preoperative IVD (%DHI = (DHI postlesion/DHI prelesion)∗100).
T2 mapping magnetic resonance imaging (MRI) sequence is usually used to reflect the water proton molecule movements in the extracellular matrix of collagen and proteoglycan [24 (link)]. At the termination of the study, the IVDs of all rat coccygeal vertebrae were scanned in a 1.5 T MRI scanner (GE, USA). The T2 signal intensities were calculated using image analysis program ImageJ to indirectly measure the extent of disc hydration. The mean T2 signal intensity in the control IVD was set as reference for that of the punctured disc in each rat. Therefore, the normalized disc intensity was presented from 0 to 1.