Sense knee 8

Measurements at 3.0 T were performed in a whole-body MRI scanner (Philips Intera) using a knee-coil (SENSE-Knee-8; Philips Healthcare) at 37°C. The T1 times were determined by imaging a series of samples simultaneously, using a series of 12 inversion recovery spin echo sequences with the shortest possible echo time of 7.46 milliseconds, a series of TI ranging from 50 to 4500 milliseconds, and a repetition time of 3400 milliseconds + TI. The flip angle was 90 degrees. The SIs of 3 different concentrations (0.25, 0.5, and 0.75 mmol Gd/L) of gadoquatrane were measured by placing a region of interest (ROI) in the homogenous center of the samples. All SIs (12 SIs) were plotted against the respective TIs, and a fitting routine was used to calculate the T1 times. The exact Gd concentrations of all samples and the r1-relaxivity were obtained in the same way as described for 1.41 T.

MR images were obtained on a Philips 1.5 T Scanner (Philips, Best Netherlands) using an eight channel knee coil (SENSE-Knee 8). Images of the patellofemoral joint were obtained in the axial plane using the following MRI sequences: (1) fat suppressed fast spin-echo (FSE) (TR/TE, 1500/15 ms; field of view (FOV), 14 cm; 256 × 256 pixels and 24 slices; slice thickness, 3 mm with 0.3 mm gap), referred as proton density fat-suppressed (PDFS) hereafter; (2) Short tau inversion recovery (TR/TE,~3700/14 ms; TI, 140 ms; FOV 14 cm; 320 × 320 pixels and 24 slices; slice thickness, 3 mm with 0.3 mm gap), referred to as STIR; (3) Fat suppressed post intravenous contrast agent (TR/TE, 500/17 ms; FOV 14 cm; 320 × 320 pixels and 24 slices; slice thickness, 3 mm with 0.3 mm gap) referred to as contrast enhanced T₁ weighted sequence with fat suppression or CE T₁W FS; and (4) 3D T₁ weighted GRE pulse sequence with fat suppression (TR/TE, 39/~5.2 ms; flip angle, 45°; FOV, 14 cm; 256 × 256 pixels and 53 sections; slice thickness, 3.0 mm; and overlap between adjacent slices, 1.5 mm) referred to as 3D gradient echo T₁ weighted fast field echo sequence (T₁W FFE). There were small parameter differences in two participants with some changes to the FOV (increased to 15 cm) and matrix size.