Reappraisal of single-sample and gamma camera methods for determination of the glomerular filtration rate with 99mTc-DTPA.
The aim of this study was to assess the clinical validity of single-sample methods and gamma camera uptake methods with 99mTc-DTPA for the estimation of the glomerular filtration rate (GFR). The study was performed in 50 patients with various degrees of renal function (29 males and 21 females; age 27-90 yrs; serum creatinine level 0.34-6.49 mg/dl). As a reference the "true" GFR (GFRt) was determined from plasma clearance by means of the two compartment model curve fitting 10 plasma samples. The GFRt of more than 30 ml/min in 46 patients was compared to the GFR which was estimated with 7 single-sample methods, two gamma camera uptake methods and 24-hour endogenous creatinine clearance (24hCcr). Close correlation was observed in all single-sample methods. The highest linear correlation was observed in the Christensen and Groth's method rewritten by Watson for a 180-min plasma sample (r = 0.991, see = 5.84 ml/min). The smallest random error was observed in the Groth and Aasted's method for a 180-min plasma (r = 0.989, see = 4.31 ml/min/1.73 m2). Our method was lowest in % absolute difference analysis (mean = 4.10%). The gamma camera uptake methods correlated significantly with the GFRt (r = 0.746-0.774), but were less reliable than any of the single-sample methods (see = 15.41 ml/min-19.14 ml/min). The lowest correlation was observed in the 24hCcr (r = 0.698, see = 50.76 ml/min/1.73 m2). The single-sample method was more accurate than the gamma camera method, and the gamma camera method was more accurate than 24hCcr. The single-sample method should be recommended for the accurate determination of the GFR with 99mTc-DTPA in a patient with mild to moderate renal dysfunction.
Department of Radiology, JR Sapporo Genenal Hospital, Japan. itohka51@ra2.so-net.ne.jp
K
K
Itoh
S
S
Tsushima
E
E
Tsukamoto
N
N
Tamaki
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000378:metabolism; D003920:Diabetes Mellitus / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D015902:Gamma Cameras; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000097:blood / Q000493:pharmacokinetics; D012044:Regression Analysis; D015203:Reproducibility of Results; D016284:Technetium Tc 99m Pentetate / Q000097:blood / Q000493:pharmacokinetics
D019275:Radiopharmaceuticals; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate