Optimization of GFR value according to kidney depth measurement methods

3033 Purpose: In patients with unusual kidney position after 99mTc-DTPA renal dynamic imaging study, the GFR (Glomerular Filtration Rate) values are significantly different according to the depth of the kidney. Thus, we tried to compare the difference of the GFR values between the depth measurement methods and in vitro test. Materials and Methods: 30 adult patients who were subjected to renal(DTPA) study. 27 patients were in usual position and 3 patients were in unusual. 555±37 MBq of 99mTc-DTPA was administrated to all patients. GE infinia gamma camera was used. GFR values were obtained in vivo(gates method) and vitro(blood). The kidney depth in vivo was calculated by three methods(Tonnensen, Manual, Taylor). In vitro, GFR was performed by blood test. Differences in the mean values of GFR and correlations between kidney depth and GFR values were evaluated using the SPSS 12.0 statistical program. Results: The GFR values for 27 patients with kidney in the usual position are as follows(1.Tonnensen 2.Manual 3.Taylor 4.Invitro); 69.3±4.2, 88.2±5.6, 77.8±4.3, 82.2±5.8. The three unusual cases are as follows, first(congenital renal anomaly): 66.4, 101.24, 69.07, 94.8, second(transplantation kidney): 12.22, 29.99, 19.36, 23.5, third(horseshoe kidney): 37.37, 93.54, 35.9, 92.5. There was a difference between tonnensen and manual in the usual position of the kidneys(p<0.05). There was no significant difference between the other methods. However, there was a significant difference in case of the unusual position of the kidneys. Correlation analysis between both kidney depth and GFR value shows pearson correlation as follows; Rt kidney: 0.298, Lt kidney: 0.322. Conclusions: When compared with the GFR values in vitro test, it was useful to calculate the GFR value by measuring the kidney depth using a manual formula in the unusual position of the kidneys . GFR values and kidney depth were significantly related.