Sonata maestro class

All data (MEG, PET and MRI) were collected from the same participants at the CERMEP imaging centre (Lyon, France). The MEG data were recorded in a magnetically shielded room using a 275-channel CTF whole-head system. The signals were band-pass filtered at 0.016-150 Hz and sampled at 600 Hz. The PET data were recorded with a Siemens HR + camera, and ^[11C]flumazenil (FMZ), an agent that binds to benzodiazepine (BZD) receptor, was used. FMZ (RO15-1788) was labeled with 11C, using the methylation process50 (link). A dynamic 3D acquisition was applied providing 12 consecutive frames of 63 contiguous 2.42 mm thick slices, with an isotropic spatial resolution near 5 mm³ FWHM (full width at half-maximum). A 68Ge transmission scan was used to measure the attenuation correction. A partial saturation protocol consisting of a single intravenous injection of a mixture of 5 mCi of ^[11C]FMZ and 0.01 mg/kg of unlabeled FMZ was used, followed by acquisition of the emission data for 55 minutes. This single injection allowed the calculation of B′max parametric images, i.e., estimates of receptor density, without arterial blood sampling51 (link). Anatomical MRIs were collected with a 1.5 Tesla scanner (Siemens Sonata Maestro Class).

All six sets of pipes were imaged independently using an axial T1-weighted sequence (TE = 9.8 ms, TR = 678 ms, slice thickness 3.5 mm, FOV 320 × 320 mm) at 1.5 T (Sonata Maestro Class, Siemens Medical Solution, Erlangen, Germany) using a 4-channel phased-array surface coil. The same sequence was repeated twice to test reproducibility. Fourteen slices per pipe were obtained.
For each image, signal intensity (SI) in arbitrary units (au) was measured by one observer using a 4-mm diameter region of interest (Horos 3.3.5, www.horosproject.info) placed approximately in the middle of the image. For each pipe, the mean and standard deviation (SD) of SI over the 14 regions of interest was calculated. To compare the SI of Gd-BOPTA and Gd-DTPA, data from all the pipes and all the measurements were averaged.
Reproducibility between SI of each pipe was tested using the Bland-Altman method. Differences of SI between pipes at the same concentration of the two sets (with or without synovial fluid) and between pipes containing Gd-BOPTA at different concentrations and Gd-DTPA were assessed using the Mann-Whitney U test. Differences of SI among the five sets of pipes containing Gd-BOPTA per each concentration were tested using the Kruskal-Wallis test. The SPSS program (v.24, IBM, NY) was used. P-value threshold was set at 0.003 for multiple comparison correction.