Signa hdxt 3.0t mri scanner

MRI slices of the nasal cavity and oropharynx region of a young male participant were taken in the supine position. The MR sequence was chosen as T2-FRFSE. The scanning was conducted successively at three orthogonal orientations (axial, sagittal and coronal plane) in the region of the UA. The axial slices were acquired with a field of view of 22×22 cm from top of the nasal cavity to the epiglottis, with 2.5 mm thickness and a 0.5 mm gap between slices. Then, the sagittal scans were performed with a field of view of 28×28 cm in the range from the external lateral wall of the left maxillary sinus to the external lateral wall of the right maxillary sinus, with 2.5 mm thickness and a 0.5 mm gap between slices. Last, the coronal slices were acquired with a field of view of 24×24 cm in the region from the tip of the nose to the posterior portion of the cervical vertebrae, with 2.5 mm thickness and a 1.5 mm gap between slices. All the images in the three orientations were obtained with a matrix of 512×512 pixels.
Spin-echo MRI of the upper airway was performed during wakefulness using a GE Signa HDxt 3.0T MRI scanner in Beijing Tongren Hospital, China. The total scan time was about 30 minutes.
This study was approved by the Ethics Committee of the Capital Medical University, Beijing, China. The participant signed a consent form prior to participation.

All MRI images were acquired using a GE Signa Hdxt 3.0-T MRI scanner (General Electric Medical Systems, Waukesha, WI) equipped with a standard 8-channel head coil. Rs-fMRI data were acquired using an echo-planar imaging (EPI) sequence with the following scan parameters: repetition time (TR) = 2000 ms, echo time (TE) = 40 ms, flip angle (FA) = 90°, 33 axial slices, slice thickness/gap = 4.0/0 mm, field of view (FOV) = 240 × 240 mm, matrix = 64 × 64, and a total of 240 volumes were collected which lasted 8 min. High-resolution 3D T1-weighted images were acquired using the following parameters: TR =8.3 ms, TE =3.3 ms, FA = 15°, FOV = 240 × 240 mm, matrix = 256 × 192, and slice thickness/gap = 1.0/0 mm. T2-weighted FLAIR images (TR = 8,000 ms, TE = 126 ms, TI = 1,500 ms, slice thickness/gap = 5.0/1.5 mm, FOV = 240 × 240 mm, and matrix = 256 × 192) were also acquired. During the scanning process, participants were told to keep their eyes closed, relax without actively thinking and stay awake in particular. Earplugs and foam padding were used to reduce scanner noise and minimize head movement.

All MRI images were collected from a GE Signa HDxt 3.0T MRI scanner (GE Medical Systems, Milwaukee, WI) equipped with a standard eight-channel head coil. Gradient specifications: amplitude 50 mT/m, slew rate 150 T/m/s. The resting-state functional MRI images were recorded with the following settings: repetition time/echo time, 2000/30 ms; flip angle, 90°; slice thickness, 3 mm; matrix size, 64 × 64; and field of view, 240 mm × 240 mm and fMRI volumes, 240 (the first four fMRI volumes were removed before analysis). The T1-weighted anatomic images were acquired in sagittal orientation with three-dimensional inversion recovery prepared fast spoiled gradient recalled sequence with following parameters: repetition time/echo time radio, 7.012/2.876 ms; inversion time, 90 ms; flip angle, 8°; field of view, 256 mm × 256 mm; slice thickness, 1.2 mm; voxel size, 1 mm × 1 mm × 1 mm; and the number of slices, 166. All the patients and healthy controls were examined in resting state with closed eyes.

DCE-MRI was performed at 3.0 T with a Signa HDxt 3.0 T MRI scanner (GE Healthcare Life Sciences, Chicago, IL, USA). All patients were scanned in a prone position with a dedicated eight-channel double-breast coil. Axial DWI sequence scanning was performed before DCE-MRI acquisition. The acquisition parameters were as follows: repetition time, 4,000 ms; flip angle, 90°; echo time, 83.30 ms; field of view, 340 × 340 mm2; matrix size, 256 × 256; slice thickness, 4.50 mm; spacing between slices, 5.00 mm; and b values, 0 and 800 s/mm². The ADC maps were calculated from diffusion images with two b values.
Second, an axial fat-saturated T1-weighted pre-contrast scan based on the VIBRANT-VX technique was acquired. After the intravenous injection of a contrast agent (Magnevist, Bayer Healthcare Pharmaceuticals, Berlin, Germany) at 4 ml/s with a dose of 0.15 mmol per kg body weight, eight post-contrast scans were acquired with the following parameters: repetition time, 4.14 ms; flip angle, 12°; echo time, 2.10 ms; slice thickness, 2.00 mm; spacing between slices, 1.00 mm; and field of view, 340 × 340 mm². Finally, eight subtraction sequences were obtained through the subtraction of each pre-contrast scan sequence from the eight post-contrast scan sequences.