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Purpose: To evaluate a flow quantification QA method on multiple MR scanners with different magnetic field strength from different manufacturer. Methods: Our previous study proposed a low-cost, reliable and convenient MRI flow quantification QA method based on a simple and compact flow contrast phantom and a power injector. Five different MR scanners (Siemens MAGNETOM Espree 1.5T, Aera 1.5T and Skyra 3T; GE Optima MR450w 1.5T and Discovery MR750w 3T) were used to test the reproducibility and sensitivity of the QA method. Flow phantom phase contrast images were acquired at magnetic field isocenter for all the MR scanners. Eight repeated acquisitions and measurements were performed on each scanner. In addition, off-center effects were tested on Siemens Espree and two GE scanners. Results: The positive flow rates measured at isocenter of five MR scanners range from +1.84± 0.01 mL/s to +2.01± 0.02 mL/s, within 8% difference from the 2mL/s flow rate provided by the power injector. The negative flow rate measured at isocenter range from −1.89± 0.01 mL/s to -2.14± 0.03 mL/s, within 7% difference from 2mL/s flow rate. Flow rate measures were most affected by off-center effect when the flow phantom was shifted 12 cm transversely and 12 cm longitudinally from the isocenter. For GE Optima scanner, positive flow of +1.53± 0.01 mL/s was measured, which is 24.5% difference from power injector flow rate. For GE Discovery scanner, negative flow of −2.68± 0.02 mL/s was measured, which is 34% difference from 2mL/s flow rate. Conclusion: This QA method was sensitive enough to detect flow quantification difference between scanners. Flow quantification errors at locations away from magnetic field isocenter due to the worse gradient fidelity can be detected by our flow quantification QA method. In conclusion, flow phantom coupled with power injector is presented to be a widely available, consistent and low cost flow quantification method. |
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