A Primary Study For Optimizing Acquisition Protocol Of Myocardial Perfusion Imaging With CZT Heart Dedicated SPECT

Objective To optimize acquisition protocol of myocardial perfusion imaging（MPI）with CZT heart dedicated SPECT（CZT SPECT）,In order to shorten the total time spent on the completion of the MPI.First,exploring the optimal and rapid imaging acquisition time and clinical applicability when using high-and low-dose one day rest/stress myocardial perfusion imaging（MPI）with cadmium zinc-cadmium heart dedicated SPECT（CZT SPECT）.second,we discussed the feasibility of early rapid myocardial perfusion imaging protocol using CZT SPECT in order to shorten the imaging waiting time prospectively.Methods The MPI data of 51patients（22males,29females,37-71years）using high-dose rest/stress protocol and 50patients（27males,23females,18-80years）using low-dose protocol with CZT SPECT were retrospectively analyzed.Every patient received 296-370MBq rest doses of^99mTc-MIBI for high dose protocol,111-222 MBq rest doses of 99mTc-MIBI for low dose protocol,stress dose is 3 times the rest.Rest and stress scans were acquired 6min and 4min for high dose protocol,8min and 6min for high dose protocol.All rest or stress data were reconstructed from list-mode raw data to obtain scan durations of1 min,2 min,etc...,up to a maximum of acquisition time.Image quality of MPI results at different acquisition times were evaluated,and semi-quantitative myocardial perfusion and function parameters were compared between these times.In addition,The patients undergoing one-day gated myocardial perfusion imaging（G-MPI）at resting/exercise conditions were collected from April 1st to 30th 2018.Early imaging（EI）was executed during 15 min after developer injected,and late imaging（LI）was carried out 30 min after.Quality assessment was performed for the images of EI and LI,and myocardial perfusion and cardiac function indexes were analyzed and compared quantitatively.Image quality and the indexes of EI and LI were statistically analyzed.The statistical methods used were paired t-test or non-parametric test,Pearson correlation analysis and Bland-Altman analysis.Results（1）All image’s quality was rated as excellent-good when acquiring 3min and 2min respectively for rest and stress images of high-dose protocol（51/51,100%）,4min and3min respectively for rest and stress images of low-dose protocol（50/50,100%）.And the quantitative perfusion parameters（SRS、SSS、TPD）and ejection fraction（EF）at this acquisition time are not different from the results at the longest acquisition time（all P>0.05）,and the result showed strong correlation（all r>0.700,P<0.001）.Bland-Altman analysis revealed good agreement between these times.The effective radiation dose per patient in the low dose group was significantly reduced.（2）There were 11 men and 19 women involved in the prospective study,26 EI images（86%）and 29 LI images（97%）were graded as"good or excellent"at resting condition（P>0.05）,and so did 29 EI images（97%）and 29 LI images（97%）（P>0.05）at exercise condition;there were no statistical differences between the results of myocardial perfusion and cardiac function indexes shown by EI and LI at rest/exercise conditions（P>0.05）,while there were high correlation and consistency existed.Conclusion The optimal imaging acquisition time of the high dose protocol for rest and stress MPI is 3min,2 min respectively,and the low dose protocol is 4 min,3 min respectively,this acquisition time obtains reliable perfusion parameters under the premise of ensuring image quality.The left ventricular ejection fraction,especially the low dose protocol can reduce the patient’s radiation dose.In addition,there was no statistically significant difference in image quality,semi-quantitative parameters of myocardial perfusion,and left ventricular function between early imaging protocol and the recommended delay time imaging protocol in terms of image quality,myocardial perfusion semi-quantitative parameters and left ventricular function measurements.The use of short acquisition time and early imaging protocol can significantly shorten the total time spent on MPI examination,and further improve the clinical performance of CZT SPECT excellent performance.