A Novel Method for Accurate Quantification of Split Glomerular Filtration Rate Using Combination of Tc-99m-DTPA Renal Dynamic Imaging and Its Plasma Clearance

Abstract

Purpose. To precisely quantify split glomerular filtration rate by Tc-99m-DTPA renal dynamic imaging and plasma clearance in order to increase its consistency among doctors. Methods. Tc-99m-DTPA renal dynamic imaging was performed according to the conventional radionuclide renal dynamic imaging by five double-blinded doctors independently and automatically calculated split GFR, namely, gGFR. Moreover, the conventional radionuclide renal dynamic imaging was assessed to only outline the kidney, blank background, and automatically calculated split GFR, gGFR <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:msup> <a:mrow/> <a:mrow> <a:mo>′</a:mo> </a:mrow> </a:msup> </a:math> . The total GFR value of patients, tGFR, was obtained by the double-plasma method. According to the formula, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mtext>Precise</c:mtext> <c:mtext> </c:mtext> <c:mtext>GFR</c:mtext> <c:mtext> </c:mtext> <c:mfenced open="(" close=")"> <c:mrow> <c:mtext>pGFR</c:mtext> </c:mrow> </c:mfenced> <c:mo>=</c:mo> <c:mtext>gGF</c:mtext> <c:msup> <c:mrow> <c:mtext>R</c:mtext> </c:mrow> <c:mrow> <c:mo>′</c:mo> </c:mrow> </c:msup> <c:mo>/</c:mo> <c:mfenced open="(" close=")"> <c:mrow> <c:mtext>gGF</c:mtext> <c:msup> <c:mrow> <c:mtext>R</c:mtext> </c:mrow> <c:mrow> <c:mo>′</c:mo> </c:mrow> </c:msup> <c:mo>+</c:mo> <c:mtext>gGF</c:mtext> <c:msup> <c:mrow> <c:mtext>R</c:mtext> </c:mrow> <c:mrow> <c:mo>′</c:mo> </c:mrow> </c:msup> </c:mrow> </c:mfenced> <c:mo>×</c:mo> <c:mtext>tGFR</c:mtext> </c:math> . The precise GFR value of the divided kidney, pGFR, was calculated. The Kendall’s <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M3"> <i:mi>W</i:mi> </i:math> test was used to compare the consistency of gGFR and pGFR drawn by five physicians. Results. According to Kendall’s <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M4"> <k:mi>W</k:mi> </k:math> consistency test, Kendall’s coefficient of concordance was 0.834, <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M5"> <m:mi>p</m:mi> <m:mo>=</m:mo> <m:mn>0.0001</m:mn> </m:math> using conventional method. The same five doctors used blank background again and the same standard Gates method to draw the kidneys, which automatically calculated gGFR <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" id="M6"> <o:msup> <o:mrow/> <o:mrow> <o:mo>′</o:mo> </o:mrow> </o:msup> </o:math> . Using input formula, the pGFR was calculated and Kendall’s <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" id="M7"> <q:mi>W</q:mi> </q:math> consistency test ( <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" id="M8"> <s:mtext>Kendal</s:mtext> <s:msup> <s:mrow> <s:mtext>l</s:mtext> </s:mrow> <s:mrow> <s:mtext>’</s:mtext> </s:mrow> </s:msup> <s:mtext>s</s:mtext> <s:mtext> </s:mtext> <s:mtext>coefficient</s:mtext> <s:mtext> </s:mtext> <s:mtext>of</s:mtext> <s:mtext> </s:mtext> <s:mtext>concordance</s:mtext> <s:mo>=</s:mo> <s:mn>0.956</s:mn> </s:math> , <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" id="M9"> <u:mi>p</u:mi> <u:mo>=</u:mo> <u:mn>0.0001</u:mn> </u:math> ). Conclusion. The combination of Tc-99m-DTPA renal dynamic imaging combined with the double-plasma method could achieve accurate split GFR, and because of the omission of influence factors, the consistency of pGFR obtained by different doctors using this method was significantly higher than that of conventional Tc-99m-DTPA renal dynamic imaging.

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