Correlations and Differences in Glomerular Filtration Rates Calculated Through In-House and Non-In-House Workstations of Scintigraphic Gamma Cameras

Technetium-99m diethylene triaminepentaacetic acid (Tc-99m DTPA) renal scintigraphy using modified Gate’s method is commonly adopted to calculate glomerular filtration rate (GFR). The purpose of this study was to find the correlations between GFRs, which are calculated by the in-house and non-in-house workstations from gamma cameras (GC) manufactured by different firms. Patients and Methods: Medical records of patients receiving Tc-99m DTPA renal scan between January and December 2016 were analyzed. Patients were allocated randomly to a GC (1 or 2). The calculated GFRs were conducted by the in-house workstation (group A: workstation 1/ GC 1; group B: workstation2/ GC 2) and the non-in-house workstation from the GC (group C: workstation 2/ GC 1; group D: workstation 1/ GC 2). All patients had their creatinine levels checked to calculate the estimated GRF (eGFR) as the reference data. Comparison of correlation and difference between GFR calculations (group A, B, C and D), eGFRs and clinical parameters was analyzed. Forty patients (24 men, 16 women) were enrolled in this study. The average of eGFRs was 63.0 ± 38.5 mL/min/1.73m2. The GFRs (group A to D) calculated were all significantly correlated with the eGFR. However, there was a significant difference between group C and eGFR (P = 0.0021), and group D and eGFR (P = 0.0262). Eight patients (20%) had changed stage of chronic kidney disease when using non-in-house workstations, compared to in-house workstations from GC. GFRs calculated by the non-in-house workstation were significantly different from eGFR. Use of workstation and GC from the same manufacturer would provide more accurate data in the clinical setting.