Estimation of Absolute Renal Uptake of 99mTc DMSA in Potential Kidney Donors and its Accuracy in Determination of Split Function | ||||
| Egyptian Journal Nuclear Medicine | ||||
| Article 6, Volume 9, Issue 9, June 2014, Page 55-65 PDF (379.67 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/egyjnm.2014.2565 | ||||
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| Abstract | ||||
| Introduction: Calculation of 99mTc DMSA split renal function (SRF) is widely used in daily clinical practice; however it does not provide information regarding the functional status of each kidney separately. Absolute renal uptake (ARU) is a valuable quantitative parameter that is capable of assessing the kidneys’ function independently. Discrepancies exist in ARU values due to various quantitative methods used and standardization of normal ARU values is probably required at different centers. Objectives: Establishment of normal ARU values derived from posterior view images. Methods: We retrospectively analyzed 80 healthy adults, potential kidney donors (64 males, mean age 29.8±8.7 years). All patients had 99mTc DMSA images. The SRF was calculated using geometric mean method.The depth of the kidneys for attenuation corrected ARU was derived Tonnensen method (Right kidney = 13.3 (W/H) + 0.7, Left kidney =13.2 (W/H) + 0.7) as well as from actual kidney depths on CT. Paired T-test, Pearson’s correlationand Kappa test were used to compare different parameters. Results: The Tonnensen based ARU was lower compared to the CT based ARU for left (20.79 ± 4.01% & 24.08 ± 4.50%; p<0.001) and right kidney (18.79 ± 4.31% & 23.23±4.9%; p<0.001). Both methods were highly correlated for left and right kidneys (r=0.921, p<0.001 & r=0.905; p<0.001) respectively. The calculated kidney depths (cm) by the Tonnensen method compared to the CT were (6.24±1.03 vs.7.48 ± 1.27; p<0.001) for left kidney and (6.28±1.04 vs. 8.09±1.42; p<0.001) for right kidney. Agreement of posterior view based ARU regarding the kidney of higher uptake versus that of geometric mean based SRF, was better for ARU based on CT depth measurement compared to that using Tonnensen equation (Kappa =0.479; p<001 vs. Kappa= 0.162; p=0.83) respectively. Conclusions: The ARU calculated based on Tonnensen method althoughis underestimated compared to that based on CT measurement, both are highly correlated. The variability in normal ARU values reported in various studies is probably multifactorial however a key factor is the method used for kidneysdepth assessment. Consequently it is recommended that local standardized reference ARU values be developed by every nuclear lab rather than using a predecided values from the literature. | ||||
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