Signa hdxt 1.5t

All patients underwent MR examinations with 1.5-T (Signa HDxt 1.5T; GE Healthcare, Chicago, IL, USA) or 3.0-T (Discovery 750w from GE Healthcare; MAGNETOM Prisma from Siemens AG, Munich, Germany; Ingenia from Philips Healthcare, Amsterdam, The Netherlands) MRI scanners with an 8/16-element phased array coil. The liver MRI technique is summarized in Supplemental Table 1 (online). All patients underwent MRI using gadobenate dimeglumine (Magnevist; Bayer Schering Pharma AG, Berlin, Germany), which was intravenously injected at a dose of 0.1 mmol/kg and a rate of 2 mL/s followed by a normal saline flush. After the administration of contrast agent, dynamic T1-weighted imaging (T1WI) was obtained in the late arterial phase (30–40 s after injection), portal venous phase (60–70 s after injection), equilibrium phase (3–4 m after injection), and delayed phase (5–8 m after injection).

All shoulder MRI examinations were performed at our institution: 137 examinations on 1.5-T (Signa HDxt 1.5-T, GE Healthcare, Milwaukee, WI, USA) scanner and 55 examinations on 3.0-T (MAGNETOM Trio/Verio, Siemens Medical Solutions, Erlangen, Germany) MRI scanners. The patients were placed in the supine position with forearm orgturned to the semi-pronation (neutral) position. The MRI protocol included oblique sagittal T1-weighted fast spin-echo images obtained on a plane perpendicular to the scapular body (repetition time/echo time, 400-800/10-15 ms; slice thickness, 4 mm; slice gap, 0.4 mm; field of view, 16 cm; matrix, 320 × 192; flip angle, 90°; and echo train length, 4).

MRI was performed using two 1.5-Tesla systems, Signa HDxt 1.5T (GE Healthcare Life Sciences, Chalfont, UK) and MAGNETOM Sonata 1.5T (Siemens AG, Munich, Germany) at the Second Affiliated Hospital of Zhejiang University School of Medicine. Two MRI protocols were used. The first protocol was a standard follow-up NPC MRI protocol for patients with NPC. Sequences for the first protocol included an axial T2-weighted fat-suppressed sequence, an axial T1-weighted spin-echo sequence and a contrast enhanced T1-weighted spin-echo sequence in the axial, coronal and sagittal planes following a bolus injection of 0.1 mmol gadopentetate dimeglumine (Gd-DTPA) (Magnevist; Schering AG; Bayer Leverkusen, Germany) per kg of body weight. The second protocol was modified to target the brain. Sequences for the second protocol included an axial T1-weighted spin-echo sequence and an axial T2-weighted turbo spin-echo sequence. Post-contrast axial, sagittal and coronal T1-weighted imaging was performed following an intravenous bolus injection of 0.1 mmol clinical gadolinium chelate per kg of body weight, and the imaging parameters were the same as for pre-contrast imaging.

All MRI data of patients with cerebral AVM were collected using a Signa HDxt 1.5 T (GE healthcare Milwaukee, WI) scanner with an eight-channel phased-array neurovascular coil to obtain T2w and magnetic resonance angiography time of flight (TOF) sequences. The T2w images were used for subsequent data processing because they provided the best tissue contrast and resolution, wherein brain tissue appeared gray, the nidus appeared black (due to flow void effects), and the CSF space appeared white. The parameters used in acquiring the T2w sequences were as follows: repetition time (TR) = 4000–5500 ms, echo time (TE) = 80–100 ms, field of view (FOV) = 260 mm, number of excitations (NEX) = 2, slice thickness = 3 mm, and slice gap = 0 mm. The parameters for acquiring TOF sequence were TR = 6.9 ms, TE = 45 ms, FOV = 260 mm, NEX = 2, slice thickness = 1.5–2 mm, and slice gap = 1.5–2 mm.

MRI was conducted with the same imaging protocol on different platforms (SIEMENS Aera 1.5 T; SIEMENS Avanto 1.5 T; GE Healthcare Signa HDxt 1.5 T; GE Healthcare Discovery 750 3.0 T) using different coils based on the location of the lesion. However, the following standard pulse sequences were used for each patient: axial T1-weighted imaging (T1WI), fat-suppressed T2-weighted imaging (T2WI), proton-density-weighted imaging (PdWI), and contrast-enhanced T1WI with or without fat suppression. Furthermore, for each patient, longitudinal images (coronal or sagittal) were acquired.