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Objective To compare the value of transvaginal ultrasound, 3.0T magnetic resonance imaging (MRI) scanning alone and in combination for diagnosis of ectopic pregnancy, so as to provide insights into early screening of ectopic pregnancy. Methods This study enrolled a total of 130 patients with suspected ectopic pregnancy admitted to Dachuan People’s Hospital in Dazhou City, Sichuan Province, China between February 2019 and December 2022. All patients underwent transvaginal ultrasound examination and 3.0T MRI scanning. The consistency of transvaginal ultrasound and 3.0T MRI with clinical diagnostic results was evaluated with surgical pathology or clinical follow-up results as the golden standards. The sensitivity, specificity, and accuracy of transvaginal ultrasound and 3.0T MRI, alone and in combination, were compared for diagnosis of ectopic pregnancy. Results Of the 130 patients with suspected ectopic pregnancy, 108 cases were confirmed with ectopic pregnancy by surgical pathology, and 22 cases were confirmed without ectopic pregnancy by clinical follow-up. The sensitivity, specificity, and accuracy of transvaginal ultrasound were 85.19% (92/108), 54.55% (12/22), and 80.00% (104/130), respectively, with 0.358 consistency with clinical diagnostic results. The sensitivity, specificity, and accuracy of 3.0T MRI were 92.59% (100/108), 81.81% (18/22), and 90.77% (118/130), respectively, with 0.694 consistency with clinical diagnostic results. The sensitivity, specificity, and accuracy of transvaginal ultrasound combined with 3.0T MRI were 98.15% (106/108), 72.73% (16/22), and 93.85% (122/130), respectively, with 0.764 consistency with clinical diagnostic results. In addition, the sensitivity and accuracy of transvaginal ultrasound combined with 3.0T MRI were significantly higher than transvaginal ultrasound alone for diagnosis of ectopic pregnancy (χ2 = 11.88 and 10.96, both P < 0.01). Conclusion Transvaginal ultrasound combined with 3.0T MRI may provide more diagnostic information for ectopic pregnancy, and is highly consistent with the clinical diagnostic results. In addition, transvaginal ultrasound combined with 3.0T MRI improves the diagnostic sensitivity and accuracy for ectopic pregnancy than transvaginal ultrasound alone.
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Objective To investigate the effect from circumferential distribution angle of forwards wedge vortex generators on aerodynamic drag reduction during flow around a cylinder, so as to provide theoretical evidences for low drag sprint garment design. Methods Forwards wedge vortex generators were reconstructed based on the NIKE’s AeroBalde. Given that the individual parts of an athlete body can be treated as multiple cylinders with varied dimensions and positions, 48 forwards wedge vortex generators were distributed as four columns on windward side of the cylinder, which were symmetrical with the YOZ plane. When the air flowed through the cylinder at the speed of 32 km/h, large eddy simulation was carried out on the computational domains which were properly meshed with polyhedral mesh to investigate the drag force, flow filed and pressure distributions. Results It was effective for drag reduction of the cylinder induced by airflow when two columns of forwards wedge vortex generators were circumferential distributed in the range of 55°-75°and the circumferential internal angle between two columns was in the range of 10° or 15°. The pressure distribution on leeward side of the cylinder was apparently changed after surface modification, which minimized the pressure drag dominant in aerodynamic drag. The drag reduction mechanism was that micro-vortices were generated downstream after flow through the forwards wedge vortex generators, which resulted in an early transition to critical flow with low drag force. Conclusions Effective aerodynamic drag reduction is achieved if forwards wedge vortex generators are properly distributed. The research findings can provide guidance for wind tunnel test and low drag sprint garment design.