Glomerular filtration rate measured by ^99mTc‐DTPA Gates method is not significantly affected by the premature or delayed initiation of image acquisition.

Purpose: This study was performed to examine the effect of non-synchronization of the radiotracer injection and image acquisition on estimates of the glomerular filtration rate (GFR) by the Gates’

Methods:

Methods: Totally 218 volunteers were selected as the research objects. Two-sample method and ^99mTc-DTPA dynamic renal imaging were used for determination of GFR (GFR_dt and GFR_Gates) respectively. We took GFR_dt as the reference method. Then we took the peak time of blood perfusion phase as the new time origin to make sure that all patients are unified on time-radioactivity counts rate curve. We moved radioactivity curve on 9 time points to simulate image acquisition forward (+20 seconds/ +15 seconds / +10 seconds/ +5 seconds), synchronous, delay (-20 seconds/ -15 seconds / -10 seconds/ -5 seconds) the completion of tracer injection, then we got nine GFR_Gates. Correlation and consistency of GFR_Gates and GFR_dt were analyzed. Variance analysis was compared the differences between different GFR_Gates.

Results: All the nine GFR_Gates had good correlation with GFR_dt. GFR_dt and GFR_Gates derived from -5s, -10s and -15s had the best correlation (r=0.827, p<0.01). The consistency between GFR_Gates derived from +20s and GFR_dt was the worst, and GFR_Gates derived from -15s and GFR_dt was the best. There were no significant differences between the nine GFR_Gates.

Conclusions: Non-synchronization of the radiotracer injection and image acquisition has no significant effect on the estimates of the GFR_Gates if the delay or forward between image acquisition and tracer injection is not more than 20 seconds. <!--EndFragment-->