GFRs Measured by Gates' Method According to 5 Background Sites: Comparison with GFR Measured by I-125-Iothalamate Method

Jung, Hyun Seok; Chung, Yong An; Kim, Sung Hoon; Kim, Chung Ho; Lee, Sung Young; Sohn, Hyung Seon; Baik, Jun Hyun; Chung, Soo Kyo

Abstract

PURPOSE
The aim was to assess how the background site affects the Gates' glomerular filtration rate (GFR) measurement using Tc-99m-DTPA in correlation with GFR by I-125-iothalamate method. MATERIAL AND METHODS: The study populations were 63 adults with 39 men and 24 women aged from 20 to 59 yrs (mean = 37.9 yrs). The following five background regions of interest were used in measurement of GFR using Gates' method: 1) lower side of each kidney (subrenal), 2) around each kidney (circumferential), 3) upper side of each kidney (suprarenal), 4) lateral side of each kidney (lateral), 5) between the two kidneys (inter-renal). We also measured GFR using I-125-iothalamate in each subject. The two studies were separated by 1 to 3 weeks. The subjects were divided into two groups by renal depth. Group 1 with renal depth> or=7cm and group 2 with renal depth < 7 cm. We calculated the means and standard deviations of the GFRs measured by two studies. And we statistically analyzed the correlation and differences among GFRs by Gates' method and the GFR by iothalamate method with correlation analysis. RESULTS: The GFRs by Gates' method using suprarenal and inter-renal background correction showed better correlation with the GFR measured by I-125-iothalamate. And GFRs measured by Gates' method showed statistically significant correlation with the GFR measured by I-125-iothalamate in the group with renal depth < 7cm. But GFRs measured by Gates' method did not show statistically significant correlation with the GFR measured by I-125-iothalamate in the group with renal depth > or=7cm. CONCLUSION: GFRs measured with Gates' method showed higher correlation with the GFR measured by I-125-iothalamate when the regions of interest were placed over the suprarenal and inter-renal backgrounds. And GFRs measured with Gates method showed statistically significant correlation with the GFR measured by I-125-iothalamate in the group with renal depth < 7cm.