A method for assessing split renal function in computed tomography: a retrospective study

INTRODUCTION: Accurate determination of the percentage of Renal contribution to their overall function is an important indicator when choosing clinical tactics for Renal transplantation and surgical interventions. The possibility of using nephroscintigraphy or complex alternative radiation methods is not always available.

OBJECTIVE: Development and validation of methods for assessing split Renal function in a standard CT scan with contrast based on specialized automatic segmentation programs or manual measurement data.

MATERIAL AND METHODS: The study included the results of a CT scan of the retroperitoneal space with contrast in 243 patients. 100 of them had nephroscintigraphy data. The Vitrea Advanced Visualization software was used for automatic segmentation of the renal parenchyma into the nephrographic phase. Data on volume (V) and average density (HU) were obtained. The values of renal parenchyma density in the native phase were performed manually. The split contribution of the Renals was determined based on the percentage ratio of the «mass» of the contrast agent in the parenchyma of each Renal, calculated as the product of the volume of the parenchyma and the average values of its density. The obtained results were compared with the nephroscintigraphy data.

To develop a manual method for calculating the volume of the renal parenchyma, three linear Renal sizes (width, thickness, and length) and three parenchymal thicknesses were measured. The average values of renal parenchyma density were obtained based on three measurements of the round ROI at different levels.

Statistics: The results obtained during the study were processed using statistical evaluation methods (correlation and covariance analysis).

RESULTS: Using data on the volume values of the Renal parenchyma obtained during automatic segmentation using regression analysis, formulas for calculating the volume of the parenchyma were obtained based on taking into account all six linear Renal sizes with additional coefficients: V=1/1000(0.92xyT–0.07y³+0.07yz²+0.19z²T), which demonstrated a high positive correlation and accuracy of the method (correlation coefficient — 0,99 (p<0,001), covariance coefficient — 0,94 (p<0,001)). When comparing two methods for determining the average values of renal parenchyma density (using round ROI and using manual circling on a coronal slice), the round ROI measurement method was chosen, which showed a slightly greater correlation with the data obtained with automatic segmentation (correlation coefficient — 0,988 (p<0,001); covariance coefficient — 0,76 (p<0,001)).

DISCUSSION: The conducted studies have confirmed the high effectiveness of the two proposed methods for assessing separate kidney function based on standard CT with contrast.

The automated method demonstrated a very high correlation with the results of dynamic nephroscintigraphy. This opens up the prospect of replacing radionuclide testing in a number of clinical situations, which will reduce radiation exposure and simplify patient examination.

An alternative manual method based on linear measurements of the kidney and the density of its parenchyma also showed high accuracy. The method is a clinically valuable solution for medical institutions that do not have expensive specialized 3D segmentation software.

CONCLUSIONS: The developed automated method of segmentation of the renal parenchyma and an alternative method based on manual measurement make it possible to obtain data on split renal function during a routine CT scan with contrast without additional radiation and financial burden on the patient.

1. Levey A.S., Stevens L.A., Schmid C.H., Zhang Y.L., Castro A.F. 3rd et al.; CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration). A new equation to estimate glomerular filtration rate // Ann. Intern. Med. 2009. May 5. Vol. 150, No. 9. Р. 604–612. doi: 10.7326/0003-4819-150-9-200905050-00006.

2. Lamb E.J., Tomson C.R., Roderick P.J. Clinical Sciences Reviews Committee of the Association for Clinical Biochemistry. Estimating kidney function in adults using formulae // Ann. Clin. Biochem. 2005. Sep. Vol. 42 (Pt 5). Р. 321–345. doi: 10.1258/0004563054889936.

3. Kayukov I.G., Galkina O.V., Timshina E.I., Zubina I.M., Miheeva A.U., Berdichevsky G.M. Creatinin in the modern evaluation of the kidneys functional condition (literature review and own data). Nephrology (SaintPetersburg), 2020, Vol. 24, No. 4, рр. 21–36 (In Russ.). https://doi.org/10.36485/1561-6274-2020-24-4-21-36.

4. Shlipak M.G., Matsushita K., Ärnlöv J., Inker L.A., Katz R., Polkinghorne K.R., Rothenbacher D., Sarnak M.J., Astor B.C., Coresh J., Levey A.S., Gansevoort R.T. CKD Prognosis Consortium. Cystatin C versus creatinine in determining risk based on kidney function // N. Engl. J. Med. 2013. Sep 5. Vol. 369, No. 10. P. 932– 943. doi: 10.1056/NEJMoa1214234.

5. Wesolowski M.J., Conrad G.R., Šámal M., Watson G., Wanasundara S.N., Babyn P., Wesolowski C.A. A simple method for determining split renal function from dynamic (99m)Tc-MAG3 scintigraphic data // Eur. J. Nucl. Med. Mol. Imaging. 2016. Mar. Vol. 43, No. 3. Р. 550–558. doi: 10.1007/s00259-015-3216-1.

6. Weyer K., Nielsen R., Petersen S.V., Christensen E.I., Rehling M., Birn H. Renal uptake of 99mTc-dimercaptosuccinic acid is dependent on normal proximal tubule receptor-mediated endocytosis // J. Nucl. Med. 2013. Jan. Vol. 54, No. 1. Р. 159–165. doi: 10.2967/jnumed.112.110528.

7. Tartaglione G., D’Addessi A., De Waure C., Pagan M., Raccioppi M., Sacco E., Cadeddu C., Vittori M., Bassi PF., Ferretti A., Al-Nahhas A., Rubello D. (99m)TcMAG3 diuretic renography in diagnosis of obstructive nephropathy in adults: a comparison between F-15 and a new procedure F+10(sp) in seated position // Clin. Nucl. Med. 2013. Vol. 38, No. 6. Р. 432–436.

8. Dawson P., Peters M. Dynamic Contrast Bolus Computed Tomography for the Assessment of Renal Function // Investigative Radiol. 1993. Vol. 28, No. 11. Р. 1039–1042. https://doi.org/10.1097/00004424-199311000-00014.

9. Tsushima Y., Blomley M.J., Okabe K. et al. Determination of glomerular filtration rate per unit renal volume using computerized tomography: correlation with conventional measures of total and divided renal function // J. Urol. 2001. Vol. 165. Р. 382–385. https://doi.org/10.1097/00005392-200102000-00007.

10. Summerlin A.L., Lockhart M.E., Strang A.M., Kolettis P.N., Fineberg N.S., Smith J.K. Determination of split renal function by 3D reconstruction of CT angiograms: a comparison with gamma camera renography // AJR Am. J. Roentgenol. 2008. Nov. Vol. 191, No. 5. Р. 1552–1558.

11. Diez A., Powelson J., Sundaram C.P., Taber T.E., Mujtaba M.A., Yaqub M.S., Mishler D.P., Goggins W.C., Sharfuddin A.A. Correlation between CT-based measured renal volumes and nuclear-renography-based split renal function in living kidney donors. Clinical diagnostic utility and practice patterns // Clin. Transplant. 2014. Jun. Vol. 28, No. 6. Р. 675–682.

12. Wahba R., Franke M., Hellmich M., Kleinert R., Cingöz T., Schmidt M.C., Stippel D.L., Bangard C. Computed Tomography Volumetry in Preoperative Living Kidney Donor Assessment for Prediction of Split Renal Function // Transplantation. 2016. Jun. Vol. 100, No. 6. Р. 1270–1277.

13. Houbois C., Haneder S., Merkt M., Morelli J.N., Schmidt M., Hellmich M., Mueller R.U., Wahba R., Maintz D., Puesken M. Can computed tomography volumetry of the renal cortex replace MAG3-scintigraphy in all patients for determining split renal function? // Eur. J. Radiol. 2018. Vol. 103. Р. 105–111.

14. Soga S., Britz-Cunningham S., Kumamaru K.K., Malek S.K., Tullius S.G., Rybicki F.J. Comprehensive comparative study of computed tomography-based estimates of split renal function for potential renal donors: modified ellipsoid method and other CT-based methods // J. Comput. Assist Tomogr. 2012. Vol. 36, No. 3. Р. 323–329.

15. Shi W., Liang X., Wu N., Zhang H., Yuan X., Tan Y. Assessment of Split Renal Function Using a Combination of Contrast-Enhanced CT and Serum Creatinine Values for Glomerular Filtration Rate Estimation // AJR Am. J. Roentgenol. 2020. Vol. 215, No. 1. Р. 142–147.

16. Alyaev Yu.G., Dzeranov N.K., Khokhlachev S.B., Borisov V.V., Fiev D.N., Demidko Yu.L., Proskura A.V., Yurova M.V. A new method for assessing separate renal function based on data from multispiral computed tomography with contrast. Urology, 2018, No. 2, pp. 26–33 (In Russ.). https://doi.org/10.18565/urology.2018.2.26-33.

17. Knox M.K., Rivers-Bowerman M.D., Bardgett H.P., Cowan N.C. Multidetector computed tomography with triple-bolus contrast medium administration protocol for preoperative anatomical and functional assessment of potential living renal donors // Eur. Radiol. 2010. Vol. 20, No. 11. Р. 2590–2599.

18. Lal H., Singh A., Prasad R., Yadav P., Akhtar J., Barai S., Mishra P., Bhadauria D., Kaul A., Prasad N., Verma P. Determination of split renal function in voluntary renal donors by multidetector computed tomography and nuclear renography: How well do they correlate? // SA J. Radiol. 2021. Vol. 25, No. 1. Р. 2009.

19. Fowler J.C., Beadsmoore C., Gaskarth M.T., Cheow H.K., Bernal R., Hegarty P., Bullock K.N., Taylor H., Dixon A.K., Peters A.M. A simple processing method allowing comparison of renal enhancing volumes derived from standard portal venous phase contrast-enhanced multidetector CT images to derive a CT estimate of differential renal function with equivalent results to nuclear medicine quantification // Br. J. Radiol. 2006. Vol. 79, No. 948. Р. 935–942. https://doi.org/10.1259/bjr/53140218.

20. Kang K.Y., Lee Y.J., Park S.C., Yang C.W., Kim Y.S., Moon I.S., Koh Y.B., Bang B.K., Choi B.S. A comparative study of methods of estimating kidney length in kidney transplantation donors // Nephrol. Dial. Transplant. 2007. Vol. 22, No. 8. Р. 2322–2327.

21. Rathore R.S., Mehta N., Pillai B.S., Sam M.P., Upendran B., Krishnamoorthy H. Variations in renal morphometry: A hospital-based Indian study // Indian J. Urol. 2016. Vol. 32, No. 1. Р. 61–64.

22. Breau R.H., Clark E., Bruner B., Cervini P., Atwell T., Knoll G., Leibovich B.C. A simple method to estimate renal volume from computed tomography // Can. Urol. Assoc. J. 2013. Vol. 7, No. 5–6. Р. 189–192.

23. Morrisroe S.N., Su R.R., Bae K.T., Eisner B.H., Hong C., Lahey S., Catalano O.A., Sahani D.V., Jackman S.V. Differential renal function estimation using computerized tomography based renal parenchymal volume measurement // J. Urol. 2010. Vol. 183, No. 6. Р. 2289–2293.

24. Rathi N., Attawettayanon W., Yasuda Y., Lewis K., Roversi G., Shah S., Wood A., Munoz-Lopez C., Palacios D.A., Li J., Abdallah N., Schober J.P., Strother M., Kutikov A., Uzzo R., Weight C.J., Eltemamy M., Krishnamurthi V., Abouassaly R., Campbell S.C. Point of care parenchymal volume analyses to estimate split renal function and predict functional outcomes after radical nephrectomy // Sci. Rep. 2023. Vol. 13, No. 1. Р. 6225.

25. Feder M.T., Blitstein J., Mason B., Hoenig D.M. Predicting differential renal function using computerized tomography measurements of renal parenchymal area // J. Urol. 2008. Vol. 180, No. 5. Р. 2110–2115.

26. Barbas A.S., Li Y., Zair M., Van J.A., Famure O., Dib M.J., Laurence J.M., Kim S.J., Ghanekar A. CT volumetry is superior to nuclear renography for prediction of residual kidney function in living donors // Clin. Transplant. 2016. Vol. 30, No. 9. Р. 1028–1035.

27. Kato F., Kamishima T., Morita K., Muto N.S., Okamoto S., Omatsu T., Oyama N., Terae S., Kanegae K., Nonomura K., Shirato H. Rapid estimation of split renal function in kidney donors using software developed for computed tomographic renal volumetry // Eur. J. Radiol. 2011. Vol. 79, No. 1. Р. 15–20.