. Author manuscript; available in PMC: 2009 Nov 1.

Published in final edited form as: AJR Am J Roentgenol. 2008 Nov;191(5):1552–1558. doi: 10.2214/AJR.07.4023

Table 2. Correction Equations.

Split Data Set	Correction Equation	R²
Uncorrected Arterial (UA)	RS = 28.892+ 0.411 * UA	0.13
Uncorrected Excretory (UE)	RS = 11.181+ 0.772 * UE	0.30
Uncorrected Volume (UV)	RS = 3.505+ 0.928 * UV	0.37
Uncorrected Patlak (UP)	RS = 20.390 + 0.586 * UP	0.24
Threshold-Corr. Arterial (CA)	RS = 29.016+ 0.406 * CA	0.14
Threshold-Corr. Excretory (CE)	RS = 9.2541+ 0.808 * CE	0.34
Threshold-Corr. Volume (CV)	RS = 1.656+ 0.963 * CV	0.40
Corrected Patlak (CP)	RS = 16.271 + 0.668 * CP	0.30

RS=Reference Standard

R² Pearson Correlation Coefficient

With R² values from the correction equations less than 0.5 for all the data sets, correction cannot improve the raw correspondence between our measured split function and the reference standard.