Design And Clinical Application Of A New Dynamic Cardiac Phantom

ObjectiveTo develop a dynamic cardiac phantom, to detect spatial resolution of multi-slice CT, to discuss multi-slice CT coronary imaging, and to quantitatively analyze several influencing factors of coronary tomography artery. It affords a new systemic method for quality assessment and assurance of coronary tomography artery.Materials and Methods(1) Development of a dynamic cardiac phantom: This phantom was designed to implement movement like sine by PC control and be set at various HR(0～100bpm). The ratio of cardiac systolic and diastolic phase was adjustable so it could simulate pumping blood very well. (2) Experimental research: An adjustable cardiac phantom was scanned using SOMATOM Sensation 16 and SOMATOM Sensation Cardiac 64 with cardiac pulsating rates of 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,100 beats per minute (bpm). The scanning speed of the former was 0.5 s/r and 0.6s/r and the latter was 0.35s/r and 0.45s/r. The raw data were reconstructed using one sector and multiple sector reconstruction algorithm. And then these data was send to Wizard and was processed with multi-planar recombination. According to the same evaluation standard of reformatted image, image quality was scored by two radiologists. The correlation between heart rate (HR), scanning speed, reconstruction algorithm, and the score of image quality were analyzed. Factorial analysis was applied. The SIQ as independent variable and the HR, scanning speed, reconstruction algorithm as dependent variables were analyzed by multiple linear regression analysis. (3) Clinical research: 25 patients were examined with SIMENSE Definition DSCT. Three dimensional reconstructions were used with volume rendering (VR), maximum intensity projection (MIP) and curved planar reformation (CPR), and the image quality and influencing factors were evaluated.Results(1) This phantom can be used as a tool for quantitatively analyzing cardiac CT image quality. (2) Results of SOMATOM Sensation 16 CT: Image quality is statistically different of different HR, scanning speed and reconstruction algorithm. The heart rate, scanning speed and reconstruction algorithm had significant influence on the SIQ. Its equation is Y ( SIQ ) = 7.30769 -0.06538×HR+0.23077×reconstruction algorithm - 1.53846×scanning speed. (3) Results of SOMATOM Sensation 64 CT: Image quality is statistically different of different HR and scanning speed. The heart rate, scanning speed had significant influence on the SIQ. There was linear regression relationship between heart rate, scanning speed and the SIQ. Its equation is Y(SIQ)= 10.01923-0.06401×HR- 5.38462×scanning speed. (4) Results of SOMATOM Definition DSCT: HR of patients is controlled less than 75bpm with scanning speed 0.35s/r and appropriate reconstruction algorithm so that we can get optimal image quality.ConclusionThis phantom is an optimal tool of quality assessment and assurance of coronary tomography artery, validating specifications of MSCT, such as high spatial resolution and analyzing influencing factors of image quality. It helps to improve image quality and can not be replaced by clinical research. With the further improvement of the phantom, it will play an important role in basal and clinical research of cardiac imaging.