9 to 86 s. Delivered volumes versus the demand volumes were plotted in Fig. 5. An excellent linear correlation was found between the demand and

delivered volumes, from 100 μl to 10.00 ml with r2 = 1. Across the entire measured range, the mean delivered volume was found to be 97.8% of the demanded volume. The standard deviation of delivered volumes was 7 μl for 100 μl and 20 μl for 10.000 ml demand volumes (mean S.D. was 9 μl in this range). By acquiring the 13C MR signal, the delivery profile of 1.5 ml of hyperpolarized pyruvate at 6.92 ml/min (13 s pumping time) was measured as it was injected into a plastic vial, see Fig. 6a. 13C spectra acquisition started simultaneously with the pump after a trigger signal from the HyperSense. The first detected signal in the vial appeared at 6 s after the injection started, with the maximum signal observed at 13 s – coinciding with the end of the injection time point. selleck chemicals For three repeat injections through a fixed tube, the overlaid absolute integral plots closely matched each other, see Fig. 6b. From measurements of the area of each curve the coefficient of variation was 2%. After the pump system had been tested in vitro

it was then employed for in vivo injections over 13 s into P22 sarcoma bearing BDIX rats using the flow diverter system. With the surface coil positioned over the tumor, 13C spectra were simultaneously acquired both from the tumor and from Tacrolimus ic50 the tail vein cannula located above the surface coil. Fig. 7a shows that the 13C signal from the tail vein

cannula signal first appeared at 3–4 s after the trigger signal started the signal acquisition and injection sequence, reflecting the time of flight of hyperpolarized substrate through the pump and cannula to the rf coil. The tumor pyruvate signal first appeared at 9–12 s after the trigger signal and reached maximum at 21–23 s. There was approximately 13 s between appearance and maximum signal in the observed tumor, closely matching the period of injection. The pH (measured post-injection using IQ150 pH meter, Hach Company, Loveland, CO) of the injected pyruvate was 7.1 ± 0.3 (mean ± S.D.) for Selleck Regorafenib 10 animals. The design of the injection system permitted reproducible administration of hyperpolarized substrate with minimal human intervention. The plastic/non-ferrous construction of the injector allows it to be positioned next to the bore of the magnet (tested at fringe magnetic field strengths of ∼1 T). In this implementation the drive shaft length was chosen so that the drive motor was outside the 5 G line. The drive shaft could be shortened or lengthened in accordance with magnet room layout, although care must be taken over choice of the diameter of longer drive shafts to prevent excessive twisting. An excellent correlation between demanded and delivered volume was found for the tested volumes: from 0.100 to 10.