Animals were anesthetized with 3.5% isoflurane in a mixture with 200 mL/min oxygen and 200 mL/min nitrous oxide and maintained at 1.5%–2% isoflurane inside the magnet. Gadolinium contrast agent (Dotarem, Guerbet, Villepinte, France) (gadoteric acid, 279.3 mg/mL, 0.5 mmol/mL) was administered intraperitoneally (100 μg/20 g) in the left abdominal quadrant 55–65 min before MRI. The induction chamber was kept warm at 37°C. Inside the magnet, the respiratory rate of the animal was monitored (SA Instruments, New York, USA) and the body temperature was maintained using a Lauda Rc6 CS recirculating water bath (Köningshofen, Germany).
MRI was performed as previously described20 22 23 (link) with a 9.4 T magnet (Agilent, Palo Alto, USA) using Avance III electronics (Bruker, Ettlingen, Germany). The system is equipped with a 12 cm inner diameter gradient system having a maximum gradient strength of 670 mT/m. The animals were imaged using a quadrature transmit/receive cryoprobe (Bruker). T1-weighted three-dimensional (3D) images were acquired with a gradient echo 3D sequence; repetition time TR: 11 ms, echo time TE: 3.695 ms, number of averages: 2, data matrix size 220×220×147 pixels, field of view 15×15×10 mm3. Images were reconstructed by zero filling to increase the apparent resolution of the image to a matrix size of 440×440×294 pixels and an apparent pixel resolution of 0.034 mm.
MRI was performed as previously described20 22 23 (link) with a 9.4 T magnet (Agilent, Palo Alto, USA) using Avance III electronics (Bruker, Ettlingen, Germany). The system is equipped with a 12 cm inner diameter gradient system having a maximum gradient strength of 670 mT/m. The animals were imaged using a quadrature transmit/receive cryoprobe (Bruker). T1-weighted three-dimensional (3D) images were acquired with a gradient echo 3D sequence; repetition time TR: 11 ms, echo time TE: 3.695 ms, number of averages: 2, data matrix size 220×220×147 pixels, field of view 15×15×10 mm3. Images were reconstructed by zero filling to increase the apparent resolution of the image to a matrix size of 440×440×294 pixels and an apparent pixel resolution of 0.034 mm.