title: Validation of curve-fitting method for blood retention of 99mTc-GSA: comparison with blood sampling method.
abstract: We investigated a curve-fitting method for the rate of blood retention of 99mTc-galactosyl serum albumin (GSA) as a substitute for the blood sampling method. Seven healthy volunteers and 27 patients with liver disease underwent 99mTc-GSA scanning. After normalization of the y-intercept as 100 percent, a biexponential regression curve for the precordial time-activity curve provided the percent injected dose (%ID) of 99mTc-GSA in the blood without blood sampling. The discrepancy between %ID obtained by the curve-fitting method and that by the multiple blood samples was minimal in normal volunteers 3.1 +/- 2.1% (mean+/-standard deviation, n = 77 sampling). Slightly greater discrepancy was observed in patients with liver disease (7.5 +/- 6.1%, n = 135 sampling). The %ID at 15 min after injection obtained from the fitted curve was significantly greater in patients with liver cirrhosis than in the controls (53.2 +/- 11.6%, n = 13; vs. 31.9 +/- 2.8%, n = 7, p < 0.0001). There was a highly linear correlation between the %IDs of 99mTc-GSA and the plasma retention rate for indocyanine green (r = -0.869, p < 0.0001, n = 27). These results indicate that the curve-fitting method provides an accurate %ID of 99mTc-GSA and could be a substitute for the blood sampling method.
authors.affiliation: Department of Radiology, Kansai Medical University, Osaka, Japan.
authors.forename: S K
authors.initials: SK
authors.lastname: Ha-Kawa
authors.forename: Y
authors.initials: Y
authors.lastname: Suga
authors.forename: K
authors.initials: K
authors.lastname: Kouda
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D000368:Aged; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008111:Liver Function Tests / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012016:Reference Values; D015203:Reproducibility of Results; D013668:Technetium Tc 99m Aggregated Albumin / Q000008:administration & dosage / Q000097:blood*; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage / Q000097:blood*
chemical_list: D013668:Technetium Tc 99m Aggregated Albumin; C070561:technetium Tc 99m DTPA-galactosyl-human serum albumin; D016284:Technetium Tc 99m Pentetate