Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstra...Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.展开更多
Calibration of medical imaging systems that provide quantitative measures relating to complex physiological flows is challenging. Physical test objects available for the purpose either offer a known simple flow far re...Calibration of medical imaging systems that provide quantitative measures relating to complex physiological flows is challenging. Physical test objects available for the purpose either offer a known simple flow far removed from the complexity of pathology (e.g. parabolic flow in a straight pipe) or complex relevant flows in which the details of the flow behaviour are unknown. This paper presents the ring vortex as a candidate for a complex flow phantom, since it is marked by inherently complex flow features that are controllable, predictable, reproducible and stable. These characteristics are demonstrated by a combination of analytical, numerical (CFD) and experimental methods. Together they provide a consistent perspective on ring vortex behaviour and highlight qualities relevant to phantom design. Discussion of the results indicates that a liquid phantom based on the ring vortex may have merit as a complex flow phantom for multimodal imaging. Furthermore, availability of such a flow reference may also serve as a benchmark for quality assurance of simulation methodologies.展开更多
目的通过建立稳态流体模型,验证3.0 T MRI快速电影相位对比(fast cine PC)序列进行血流动力学测量的准确性。方法将直径为3.0mm的医用塑料管固定在水模中,塑料管的一端连接高压注射器,高压注射器以不同流速(0.5、1.0、1.5、2.0、2.5、3....目的通过建立稳态流体模型,验证3.0 T MRI快速电影相位对比(fast cine PC)序列进行血流动力学测量的准确性。方法将直径为3.0mm的医用塑料管固定在水模中,塑料管的一端连接高压注射器,高压注射器以不同流速(0.5、1.0、1.5、2.0、2.5、3.0、3.5、4.0 mL/s)向管腔内注射0.9%氯化钠溶液,管的另一端连入量筒。将流体模型中心置于头部8通道线圈中心,平行放置的医用塑料管与磁体长轴一致。应用3.0TMRI扫描仪进行fastcine PC序列扫描,扫描层面垂直于所测管腔长轴。在不同流速、不同观测者(2名)、不同流动方向(相向和相反)、不同倾斜角度(0°、20°、30°、45°)对流速进行测量。对图像进行后处理。测定感兴趣区流速,进行统计学分析。结果实际流动方向与流速编码方向相同时测得的流速值分别为6.75、13.90、21.14、28.69、36.52、42.48、50.49、57.10 cm/s;实际流动方向与流速编码方向相反时测得的流速值分别为8.09、14.76、22.53、29.79、36.61、44.75、51.08、54.94 cm/s。管腔内实际流速为42.46 cm/s时,不同倾斜角度测得的流速值分别为42.48、42.77、42.38、42.94、42.47、42.62、42.59 cm/s。测量速度与实际速度间差异无统计学意义,且呈正相关(r=0.99,P<0.000 1)。2名观察者的测量值之间差异无统计学意义(t=-0.87,P=0.41>0.05)。液体流动方向与流速编码方向相同、相反测得的流速与实际流速两两之间差异无统计学意义(F=3.51,P=0.06>0.05)。不管管腔在各个方向有无角度,测得的流速与实际流速之间差异均无统计学意义(t=2.01,P=0.09>0.05)。结论 3.0 T fast cine PC序列可以准确测量稳态流体模型流速,为人体血流动力学检测的临床应用提供了可靠的实验依据。展开更多
文摘Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.
文摘Calibration of medical imaging systems that provide quantitative measures relating to complex physiological flows is challenging. Physical test objects available for the purpose either offer a known simple flow far removed from the complexity of pathology (e.g. parabolic flow in a straight pipe) or complex relevant flows in which the details of the flow behaviour are unknown. This paper presents the ring vortex as a candidate for a complex flow phantom, since it is marked by inherently complex flow features that are controllable, predictable, reproducible and stable. These characteristics are demonstrated by a combination of analytical, numerical (CFD) and experimental methods. Together they provide a consistent perspective on ring vortex behaviour and highlight qualities relevant to phantom design. Discussion of the results indicates that a liquid phantom based on the ring vortex may have merit as a complex flow phantom for multimodal imaging. Furthermore, availability of such a flow reference may also serve as a benchmark for quality assurance of simulation methodologies.
文摘目的通过建立稳态流体模型,验证3.0 T MRI快速电影相位对比(fast cine PC)序列进行血流动力学测量的准确性。方法将直径为3.0mm的医用塑料管固定在水模中,塑料管的一端连接高压注射器,高压注射器以不同流速(0.5、1.0、1.5、2.0、2.5、3.0、3.5、4.0 mL/s)向管腔内注射0.9%氯化钠溶液,管的另一端连入量筒。将流体模型中心置于头部8通道线圈中心,平行放置的医用塑料管与磁体长轴一致。应用3.0TMRI扫描仪进行fastcine PC序列扫描,扫描层面垂直于所测管腔长轴。在不同流速、不同观测者(2名)、不同流动方向(相向和相反)、不同倾斜角度(0°、20°、30°、45°)对流速进行测量。对图像进行后处理。测定感兴趣区流速,进行统计学分析。结果实际流动方向与流速编码方向相同时测得的流速值分别为6.75、13.90、21.14、28.69、36.52、42.48、50.49、57.10 cm/s;实际流动方向与流速编码方向相反时测得的流速值分别为8.09、14.76、22.53、29.79、36.61、44.75、51.08、54.94 cm/s。管腔内实际流速为42.46 cm/s时,不同倾斜角度测得的流速值分别为42.48、42.77、42.38、42.94、42.47、42.62、42.59 cm/s。测量速度与实际速度间差异无统计学意义,且呈正相关(r=0.99,P<0.000 1)。2名观察者的测量值之间差异无统计学意义(t=-0.87,P=0.41>0.05)。液体流动方向与流速编码方向相同、相反测得的流速与实际流速两两之间差异无统计学意义(F=3.51,P=0.06>0.05)。不管管腔在各个方向有无角度,测得的流速与实际流速之间差异均无统计学意义(t=2.01,P=0.09>0.05)。结论 3.0 T fast cine PC序列可以准确测量稳态流体模型流速,为人体血流动力学检测的临床应用提供了可靠的实验依据。
