Multicenter trial validation of a camera-based method to measure Tc-99m mercaptoacetyltriglycine, or Tc-99m MAG3, clearance.
OBJECTIVE
To evaluate an improved camera-based method for calculating the clearance of technetium-99m mercaptoacetyltriglycine (MAG3) in a multicenter trial.


METHODS
Tc-99m MAG3 scintigraphy was performed in 49 patients at three sites in the United States and Canada. The percentage of the injected dose of Tc-99m MAG3 in the kidney at 1-2, 1.0-2.5, and 2-3 minutes after injection was correlated with the plasma-based Tc-99m MAG3 clearances. The data were combined with the results obtained in 20 additional patients in a previously published pilot study.


RESULTS
Regression models correlating the plasma-based Tc-99m MAG3 clearance with the percentage uptake in the kidney for each time interval were developed; there was no statistically significant difference among sites in the regression equations. Correction for body surface area statistically significantly (P < .005) improved the correlation coefficient for each time interval. For the 1.0-2.5-minute interval, the body surface area-corrected correlation coefficient for the four combined sites was .87, and it improved to .93 when one outlier was omitted from the analysis. Similar results were obtained with the other time intervals. Independent processing by two observers showed no clinically important differences in the percentage dose in the kidney or in relative function.


CONCLUSIONS
An improved camera-based method to calculate the clearance of Tc-99m MAG3 was validated in a multicenter trial.
Taylor
A
A
Department of Radiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
Manatunga
A
A
Morton
K
K
Reese
L
L
Prato
F S
FS
Greenberg
E
E
Folks
R
R
Kemp
B J
BJ
Jones
M E
ME
Corrigan
P E
PE
Galt
J
J
Eshima
L
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D001830:Body Surface Area; D016903:Drug Monitoring; D005260:Female; D015902:Gamma Cameras / Q000592:standards*; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012044:Regression Analysis; D017596:Renal Plasma Flow, Effective; D015203:Reproducibility of Results; D017263:Technetium Tc 99m Mertiatide / Q000097:blood / Q000493:pharmacokinetics; D013997:Time Factors
D017263:Technetium Tc 99m Mertiatide