- Email: [email protected]
Usefulness of Multi-Detector Computed Tomography Scanning as a Replacement for Diethylenetriamine Pentaacetic Acid
Usefulness of Multi-Detector Computed Tomography Scanning as a Replacement for Diethylenetriamine Pentaacetic Acid H.H. Leea, W.K. Hana,b, S.K. Kanga, K.H. Huhc, M.S. Kimc, S.I. Kimc, Y.S. Kimc, and Y.E. Yoond,* a Department of Urology, Yonsei University College of Medicine, Urological Science Institute, Seoul, Korea; bBrain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Korea; cDepartment of Transplantation Surgery, Research Institute for Transplantation, Yonsei University College of Medicine, Seoul, Korea; and dDepartment of Urology, Hanyang University College of Medicine, Seoul, Korea
ABSTRACT Background. Diethylenetriamine pentaacetic acid (DTPA) and multi-detector computed tomography (MDCT) can predict postoperative estimated glomerular filtration rate (eGFR) in a live kidney donor. Accordingly, we compared predicted eGFR measured by use of DTPA and MDCT. Methods. From January 2013 to May 2015, 264 live kidney donors were enrolled. All donors underwent preoperative DTPA and MDCT, and bilateral renal cortex volume was measured by use of MDCT. We estimated DTPA-eGFR [remaining split renal function (%) preoperative eGFR] and Vol-eGFR [remaining renal volume/total renal volume (%) preoperative eGFR] and analyzed DTPA-eGFR, Vol-eGFR, and Modification of Diet in Renal Disease (MDRD)-eGFR during week 1 and in months 1, 3, and 6. Additionally, we compared DTPA-eGFR and Vol-eGFR by use of the formula DeGFR (maximum eGFR minus minimum eGFR during 6 months). Results. The mean DTPA-eGFR and Vol-eGFR values (mL/min/1.73 m2) were 52.97 10.32 and 51.26 10.26, respectively. Predictions of the dominant side did not agree in 113 of 303 (37.3%) cases. Postoperative MDRD-eGFR exhibited a statistically significant correlation with total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001). A significant correlation was found between DeGFR and total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001). Receiver operating characteristic curves were generated to predict the possibility of eGFR <60 mL/min/1.73 m2 at 6 months, using DTPA-eGFR and Vol-eGFR, which indicated that DTPA-eGFR (area under the curve ¼ 0.858; P < .0001) and Vol-eGFR (area under the curve ¼ 0.878; P < .0001) could predict chronic kidney disease class III at 6 months. Conclusions. MDRD-eGFR, Vol-eGFR, and DTPA-eGFR were significantly correlated. Moreover, Vol-eGFR and DTPA-eGFR exhibited high predictive value for chronic kidney disease class III at 6 months, whereas Vol-eGFR was a good predictor of renal function recovery.
I
T has been established that kidney transplantation is a better method for improving the quality of life in patients with end-stage renal disease (ESRD) than is hemodialysis [1]. However, a detailed surgical plan is required to ensure the safety of the live kidney donor at the time of the surgery to ensure optimal transplant results [2]. As well, the results of various tests are evaluated to minimize the ª 2017 Elsevier Inc. All rights reserved. 230 Park Avenue, New York, NY 10169
Transplantation Proceedings, 49, 1023e1026 (2017)
progression to ESRD in live kidney donors. Accordingly, we assessed 24-hour urine creatinine clearance, the estimated
*Address correspondence to Young Eun Yoon, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea. E-mail: [email protected] 0041-1345/17 http://dx.doi.org/10.1016/j.transproceed.2017.03.056
1023
1024
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glomerular filtration rate (eGFR), diethylenetriamine pentaacetic acid (DTPA) clearance and performed multidetector computed tomography (MDCT), which enabled the evaluation of renal function in the live kidney donor. To determine the side of the nephrectomy, DTPA scintigraphy is used to evaluate split renal function [3]. Nonetheless, the MDCT reconstruction images yield accurate measurements of the kidney volume. As well, MDCT provides anatomical details of the kidney, vasculature, and the collecting system and aids in the diagnosis of kidney abnormalities [4,5]. Furthermore, MDCT has shown a high level of agreement with DTPA scans in the determination of split renal function; thus, the feasibility of only performing MDCT in live kidney donors has been proposed [6]. Both DTPA renography and MDCT can predict postoperative eGFR in a live kidney donor. Accordingly, the aim of our study was to compare predicted eGFR values measured by use of a DTPA scan and MDCT.
METHODS The study was reviewed and approved by the institutional review board and the ethics committee. Preoperative and postoperative evaluations were performed in 264 patients who underwent donor nephrectomy from January 2013 to May 2015. All surgeries were performed by 2 surgeons who used video-assisted mini-laparotomy surgery (VAMS) techniques [7]. We evaluated routine blood tests, DTPA renal scans, and CT angiography in all live kidney donors. After surgery, routine lab tests were performed daily for 3 days until the patients were discharged. We followed the patients postoperatively for 6 months. In month 6, we classified the donors who exhibited eGFR rates <60 mL/min/1.73 m2 as the chronic kidney disease (CKD) group. The Modification of Diet in Renal Disease (MDRD) formula was used to calculate eGFR rates. Before surgery, MDCT and DTPA scans were performed on all patients and the bilateral renal volume was measured by MDCT. We estimated DTPA-eGFR [remaining split renal function (%) preoperative eGFR] and Vol-eGFR [remaining renal volume/total renal volume (%) preoperative eGFR], and analyzed DTPA-eGFR, Vol-eGFR, and MDRD-eGFR in week 1 and in months 1, 3, and 6. As well, we
compared DTPA-eGFR and Vol-eGFR by use of the formula
DeGFR (maximum eGFR minus minimum eGFR during 6 months). CT Protocols All CT examinations were performed with the use of a standardized examination protocol and a multi-slice, 64edetector row helical CT scanner (Lightspeed, GE Medical Systems; Milwaukee, Wis, United States). Scanning was initiated through the use of a scout image that covered the abdomen. A pre-contrast image was acquired with 2.5-mm slices and a table rotation time of 0.5 seconds at 120 kV and 100 mAs. The arterial and venous phases were obtained 12 seconds and 60 seconds after the initiation of the contrast bolus, respectively. The arterial phase included a volume covering the diaphragm to the pelvis. After acquiring the image, the arterial and venous phase images were reconstructed through the use of 3-mm and 1-mm axial images and 3-mm coronal images. As well, a 3-dimensional reconstruction image was acquired with the use of 0.625-mm slices. The 3-dimensional images of both kidneys were segmented and measured with the use of the workstation multiplanar reformation and tissue segmentation packages. The functional renal parenchyma was outlined in a transverse section and then multiplied by slice thickness to obtain the renal volume (Fig 1).
DTPA Protocols For 99mTc-DTPA scintigraphy, the donors were hydrated with 5 mL water/kg body weight 30 minutes before the administration of 370 MBq of DTPA. To measure GFR from the DTPA plasma clearance, 3 mL of blood was collected from all donors 4 hours after injection at a site that was distinct from the radionuclide injection site. GFR was measured by use of a single sample and the Christensen-Groth method (Fig 1) [8]. The relationships between the values measured perioperatively and the recovery of renal function were analyzed by Pearson correlate analysis at 6 months. We classified the donors who exhibited eGFR rates <60 mL/min/1.73 m2 as the CKD group, and receiver operating characteristic curves were generated. A value of P < .05 was regarded as statistically significant. All data analyses were conducted with the use of SPSS software version 23.0 (IBM SPSS Statistics, IBM Corporation; Armonk, NY, United States).
Fig 1. Renogram and split renal function by use of DTPA (left); 3-dimensional kidney volume by use of MDCT (right).
MDCT SCANNING AS REPLACEMENT FOR DTPA
1025
DISCUSSION
Table 1. Characteristics of the Live Kidney Donor Population With 6-Month Follow-Up Total Patients Age, years Sex, n (%) Male Female Body mass index, kg/m2 Laterality, n (%) Left Right Preoperative eGFR (MDRD), mL/min/1.73 m2 Predicted postoperative eGFR, mL/min/1.73 m2 DTPA-eGFR Vol-eGFR
A detailed surgical plan is required for kidney transplantation surgeries to ensure the safety of the live kidney donors and to achieve an optimal recipient outcome. To minimize the occurrence of ESRD in live kidney donors, various preoperative evaluations are performed. As well, transplantation of an insufficient nephron volume cannot satisfy the metabolic demand of recipients and can eventually cause kidney hyperfiltration. Additionally, this might result in the progression of kidney disease, which is significant because it could result in chronic allograft failure [9]. Among the evaluations performed, DTPA scans are used to evaluate the preoperative renal function, whereas MDCT is used for anatomical evaluations. Furthermore, DTPA is considered the gold standard for splitting the GFR between the left and right kidneys. However, the ability to perform DTPA might not be available in every hospital, which could be an obstacle to kidney donation in many countries. In previous studies, to prove the association between the nephron volume and the graft outcome, the kidney volume was calculated by use of ultrasound to measure either the donor body surface area or the donor kidney. Recently, not only the anatomy of the donor kidney but also the pretransplantation kidney volume were measured by use of MDCT [10]. MDCT has several merits for measuring kidney volume. First, it is less invasive than conventional angiography. Second, it can predict the outline of the kidney more accurately. MDCT also makes it easy to differentiate the main vessel, ureter, and the renal parenchymal. Thus, MDCT has advantages because it accurately analyzes the kidney parenchymal volume and represents the actual nephron using volumetric software [10,11]. Accordingly, the relative GFR can be estimated by the relative ratio of the left and right kidney volumes [12]. Although many studies have been conducted to measure eGFR and split renal function by using MDCT, no correlation has been drawn between the imaging used to determine the split kidney function in a live kidney donor during postoperative kidney function [11,13], primarily because the previous reports were too complicated and limited for clinical use. However, we estimated DTPA-eGFR and Vol-eGFR as well as
264 42.29 11.48 122 (46.2) 142 (53.8) 23.4 2.49 240 (90.9) 24 (9.1) 103.62 20.09 52.97 10.32 51.26 10.26
RESULTS
The baseline and demographic characteristics of the live donors included in the study are summarized in Table 1. The study population consisted of 264 live donors, of which 122 donors (46.2%) were male and 142 (53.8%) were female. The mean age of the donors was 42.29 11.48 years, and the follow-up period was 6 months. The mean body mass index of the donors was 23.4 2.49 kg/m2. Among the 264 surgeries, 240 (90.9%) were performed on the left side and 24 (9.1%) were performed on the right side. The mean preoperative eGFR was 103.62 20.09 mL/ min/1.73 m2. The mean DTPA-eGFR and Vol-eGFR values were 52.97 10.32 (mL/min/1.73 m2) and 51.26 10.26 (mL/min/1.73 m2), respectively. The eGFR, which was measured postoperatively in week 1 and in months 1, 3, and 6, exhibited a statistically significant correlation with total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001; Table 2). A significant correlation was likewise detected between DeGFR and total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001; Table 2). Furthermore, 101 patients had an eGFR <60 mL/min/1.73 m2. Receiver operating characteristic curves were generated to predict the possibility of detecting eGFR <60 mL/min/1.73 m2 at 6 months, using DTPA-eGFR and Vol-eGFR, which revealed that DTPA-eGFR (area under the curve ¼ 0.858; P < .0001) and Vol-eGFR (area under the curve ¼ 0.878; P < .0001) could predict CKD class III at 6 months (Fig 2).
Table 2. Pearson Correlation of MDCT Total Renal Volume (cm3), DTPA-eGFR, Vol-eGFR, and Postoperative eGFR (MDRD) MDCT Total Renal Volume (cm3) Pearson (r2)
Coefficient
MDCT total renal volume 1 DTPA-eGFR 0.102 Vol-eGFR 0.136* Postoperative eGFR (MDRD) (mL/min/1.73 m2) eGFR (MDRD) 1 week 0.253* eGFR (MDRD) 1 month 0.159* eGFR (MDRD) 3 months 0.153* eGFR (MDRD) 6 months 0.192* DeGFR 0.024 *P < .05.
DTPA-eGFR (mL/min/1.73 m2)
Vol-eGFR (mL/min/1.73 m2)
P
Coefficient
P
Coefficient
.079 .019
1 0.949*
.000
1
.000 .008 .015 .005 .693
0.559* 0.685* 0.688* 0.711* 0.268*
.000 .000 .000 .000 .000
0.602* 0.726* 0.711* 0.747* 0.284*
P
Mean SD
329.61 72.10 52.97 10.32 51.26 10.26 .000 .000 .000 .000 .000
57.80 63.90 64.11 65.88 11.94
10.96 11.49 12.16 13.12 8.66
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LEE, HAN, KANG ET AL
be eliminated in select patients who have normal renal morphology and size differentiation. Moreover, the current study indicated that Vol-eGFR and DTPA-eGFR demonstrated increased predictive value for CKD class III at 6 months and that Vol-eGFR was a good predictor of renal function recovery. REFERENCES
Fig 2. Prediction of postoperative eGFR <60 mL/min/1.73 m2 at 6 months. The area under the curve (receiver operating characteristic curve) is shown for DTPA-eGFR (area ¼ 0.858; 95% confidence interval, 0.804e0.911; P ¼ .000) and Vol-eGFR (area ¼ 0.878; 95% confidence interval, 0.829e0.928; P ¼ .000).
postoperative eGFRs in live kidney donors by using DTPA and MDCT, which proved to be much easier than the previous report. Our results indicated that MDRD-eGFR was significantly correlated with total renal volume, DTPA-GFR, and Vol-eGFR (Table 2). Also, we predicted the possibility of detecting an eGFR <60 mL/min/1.73 m2 at 6 months by using DTPA-eGFR and Vol-eGFR and determined that the 2 estimated values were a good predictor of CKD class III at 6 months. As well, we confirmed that DTPA-eGFR and Vol-eGFR are significantly correlated with eGFR. Likewise, Vol-eGFR can be used as a prognostic factor of renal function in a live kidney donor; thus, we concluded that MDCT could replace the use of DTPA. CONCLUSIONS
MDRD-eGFR, Vol-eGFR, and DTPA-eGFR were significantly correlated. Hence, we conclude that DTPA scans, which are routinely performed in living kidney donors, could
[1] Wolfe RA, Ashby VB, Milford EL, et al. Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant. N Engl J Med 1999;341:1725e30. [2] Muzaale AD, Massie AB, Wang MC, et al. Risk of end-stage renal disease following live kidney donation. JAMA 2014;311: 579e86. [3] Abramowicz D, Cochat P, Claas FH, et al. European Renal Best Practice Guideline on kidney donor and recipient evaluation and perioperative care. Nephrol Dial Transplant 2015;30:1790e7. [4] Sommer G, Bouley D, Frisoli J, et al. Determination of 3-dimensional zonal renal volumes using contrast-enhanced computed tomography. J Comput Assist Tomogr 2007;31:209e13. [5] Hanninen EL, Denecke T, Stelter L, et al. Preoperative evaluation of living kidney donors using multirow detector computed tomography: comparison with digital subtraction angiography and intraoperative findings. Transpl Int 2005;18:1134e41. [6] Diez A, Powelson J, Sundaram CP, et al. Correlation between CT-based measured renal volumes and nuclearrenography-based split renal function in living kidney donors: clinical diagnostic utility and practice patterns. Clin Transplant 2014;28:675e82. [7] Choi KH, Yang SC, Lee SR, et al. Standardized videoassisted retroperitoneal minilaparotomy surgery for 615 living donor nephrectomies. Transpl Int 2011;24:973e83. [8] Blaufox MD, Aurell M, Bubeck B, et al. Report of the Radionuclides in Nephrourology Committee on renal clearance. J Nucl Med 1996;37:1883e90. [9] Oh CK, Jeon KO, Kim HJ, et al. Metabolic demand and renal mass supply affecting the early graft function after living donor kidney transplantation. Kidney Int 2005;67:744e9. [10] Choi JY, Kwon OJ. Is the graft function of living donor renal transplants associated with renal mass matching by computed tomography angiographic volumetry? Transplant Proc 2013;45: 2919e24. [11] Yokoyama N, Ishimura T. Usefulness of three-dimensional computerized tomographic volumetry for determining split renal function in donors for living-related kidney transplantation. Transplant Proc 2015;47:588e90. [12] Halleck F, Diederichs G, Koehlitz T, et al. Volume matters: CT-based renal cortex volume measurement in the evaluation of living kidney donors. Transpl Int 2013;26:1208e16. [13] Barbas AS, Li Y, Zair M, et al. CT volumetry is superior to nuclear renography for prediction of residual kidney function in living donors. Clin Transplant 2016;30:1028e35.
ABSTRACT Background. Diethylenetriamine pentaacetic acid (DTPA) and multi-detector computed tomography (MDCT) can predict postoperative estimated glomerular filtration rate (eGFR) in a live kidney donor. Accordingly, we compared predicted eGFR measured by use of DTPA and MDCT. Methods. From January 2013 to May 2015, 264 live kidney donors were enrolled. All donors underwent preoperative DTPA and MDCT, and bilateral renal cortex volume was measured by use of MDCT. We estimated DTPA-eGFR [remaining split renal function (%) preoperative eGFR] and Vol-eGFR [remaining renal volume/total renal volume (%) preoperative eGFR] and analyzed DTPA-eGFR, Vol-eGFR, and Modification of Diet in Renal Disease (MDRD)-eGFR during week 1 and in months 1, 3, and 6. Additionally, we compared DTPA-eGFR and Vol-eGFR by use of the formula DeGFR (maximum eGFR minus minimum eGFR during 6 months). Results. The mean DTPA-eGFR and Vol-eGFR values (mL/min/1.73 m2) were 52.97 10.32 and 51.26 10.26, respectively. Predictions of the dominant side did not agree in 113 of 303 (37.3%) cases. Postoperative MDRD-eGFR exhibited a statistically significant correlation with total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001). A significant correlation was found between DeGFR and total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001). Receiver operating characteristic curves were generated to predict the possibility of eGFR <60 mL/min/1.73 m2 at 6 months, using DTPA-eGFR and Vol-eGFR, which indicated that DTPA-eGFR (area under the curve ¼ 0.858; P < .0001) and Vol-eGFR (area under the curve ¼ 0.878; P < .0001) could predict chronic kidney disease class III at 6 months. Conclusions. MDRD-eGFR, Vol-eGFR, and DTPA-eGFR were significantly correlated. Moreover, Vol-eGFR and DTPA-eGFR exhibited high predictive value for chronic kidney disease class III at 6 months, whereas Vol-eGFR was a good predictor of renal function recovery.
I
T has been established that kidney transplantation is a better method for improving the quality of life in patients with end-stage renal disease (ESRD) than is hemodialysis [1]. However, a detailed surgical plan is required to ensure the safety of the live kidney donor at the time of the surgery to ensure optimal transplant results [2]. As well, the results of various tests are evaluated to minimize the ª 2017 Elsevier Inc. All rights reserved. 230 Park Avenue, New York, NY 10169
Transplantation Proceedings, 49, 1023e1026 (2017)
progression to ESRD in live kidney donors. Accordingly, we assessed 24-hour urine creatinine clearance, the estimated
*Address correspondence to Young Eun Yoon, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul, 04763, Korea. E-mail: [email protected] 0041-1345/17 http://dx.doi.org/10.1016/j.transproceed.2017.03.056
1023
1024
LEE, HAN, KANG ET AL
glomerular filtration rate (eGFR), diethylenetriamine pentaacetic acid (DTPA) clearance and performed multidetector computed tomography (MDCT), which enabled the evaluation of renal function in the live kidney donor. To determine the side of the nephrectomy, DTPA scintigraphy is used to evaluate split renal function [3]. Nonetheless, the MDCT reconstruction images yield accurate measurements of the kidney volume. As well, MDCT provides anatomical details of the kidney, vasculature, and the collecting system and aids in the diagnosis of kidney abnormalities [4,5]. Furthermore, MDCT has shown a high level of agreement with DTPA scans in the determination of split renal function; thus, the feasibility of only performing MDCT in live kidney donors has been proposed [6]. Both DTPA renography and MDCT can predict postoperative eGFR in a live kidney donor. Accordingly, the aim of our study was to compare predicted eGFR values measured by use of a DTPA scan and MDCT.
METHODS The study was reviewed and approved by the institutional review board and the ethics committee. Preoperative and postoperative evaluations were performed in 264 patients who underwent donor nephrectomy from January 2013 to May 2015. All surgeries were performed by 2 surgeons who used video-assisted mini-laparotomy surgery (VAMS) techniques [7]. We evaluated routine blood tests, DTPA renal scans, and CT angiography in all live kidney donors. After surgery, routine lab tests were performed daily for 3 days until the patients were discharged. We followed the patients postoperatively for 6 months. In month 6, we classified the donors who exhibited eGFR rates <60 mL/min/1.73 m2 as the chronic kidney disease (CKD) group. The Modification of Diet in Renal Disease (MDRD) formula was used to calculate eGFR rates. Before surgery, MDCT and DTPA scans were performed on all patients and the bilateral renal volume was measured by MDCT. We estimated DTPA-eGFR [remaining split renal function (%) preoperative eGFR] and Vol-eGFR [remaining renal volume/total renal volume (%) preoperative eGFR], and analyzed DTPA-eGFR, Vol-eGFR, and MDRD-eGFR in week 1 and in months 1, 3, and 6. As well, we
compared DTPA-eGFR and Vol-eGFR by use of the formula
DeGFR (maximum eGFR minus minimum eGFR during 6 months). CT Protocols All CT examinations were performed with the use of a standardized examination protocol and a multi-slice, 64edetector row helical CT scanner (Lightspeed, GE Medical Systems; Milwaukee, Wis, United States). Scanning was initiated through the use of a scout image that covered the abdomen. A pre-contrast image was acquired with 2.5-mm slices and a table rotation time of 0.5 seconds at 120 kV and 100 mAs. The arterial and venous phases were obtained 12 seconds and 60 seconds after the initiation of the contrast bolus, respectively. The arterial phase included a volume covering the diaphragm to the pelvis. After acquiring the image, the arterial and venous phase images were reconstructed through the use of 3-mm and 1-mm axial images and 3-mm coronal images. As well, a 3-dimensional reconstruction image was acquired with the use of 0.625-mm slices. The 3-dimensional images of both kidneys were segmented and measured with the use of the workstation multiplanar reformation and tissue segmentation packages. The functional renal parenchyma was outlined in a transverse section and then multiplied by slice thickness to obtain the renal volume (Fig 1).
DTPA Protocols For 99mTc-DTPA scintigraphy, the donors were hydrated with 5 mL water/kg body weight 30 minutes before the administration of 370 MBq of DTPA. To measure GFR from the DTPA plasma clearance, 3 mL of blood was collected from all donors 4 hours after injection at a site that was distinct from the radionuclide injection site. GFR was measured by use of a single sample and the Christensen-Groth method (Fig 1) [8]. The relationships between the values measured perioperatively and the recovery of renal function were analyzed by Pearson correlate analysis at 6 months. We classified the donors who exhibited eGFR rates <60 mL/min/1.73 m2 as the CKD group, and receiver operating characteristic curves were generated. A value of P < .05 was regarded as statistically significant. All data analyses were conducted with the use of SPSS software version 23.0 (IBM SPSS Statistics, IBM Corporation; Armonk, NY, United States).
Fig 1. Renogram and split renal function by use of DTPA (left); 3-dimensional kidney volume by use of MDCT (right).
MDCT SCANNING AS REPLACEMENT FOR DTPA
1025
DISCUSSION
Table 1. Characteristics of the Live Kidney Donor Population With 6-Month Follow-Up Total Patients Age, years Sex, n (%) Male Female Body mass index, kg/m2 Laterality, n (%) Left Right Preoperative eGFR (MDRD), mL/min/1.73 m2 Predicted postoperative eGFR, mL/min/1.73 m2 DTPA-eGFR Vol-eGFR
A detailed surgical plan is required for kidney transplantation surgeries to ensure the safety of the live kidney donors and to achieve an optimal recipient outcome. To minimize the occurrence of ESRD in live kidney donors, various preoperative evaluations are performed. As well, transplantation of an insufficient nephron volume cannot satisfy the metabolic demand of recipients and can eventually cause kidney hyperfiltration. Additionally, this might result in the progression of kidney disease, which is significant because it could result in chronic allograft failure [9]. Among the evaluations performed, DTPA scans are used to evaluate the preoperative renal function, whereas MDCT is used for anatomical evaluations. Furthermore, DTPA is considered the gold standard for splitting the GFR between the left and right kidneys. However, the ability to perform DTPA might not be available in every hospital, which could be an obstacle to kidney donation in many countries. In previous studies, to prove the association between the nephron volume and the graft outcome, the kidney volume was calculated by use of ultrasound to measure either the donor body surface area or the donor kidney. Recently, not only the anatomy of the donor kidney but also the pretransplantation kidney volume were measured by use of MDCT [10]. MDCT has several merits for measuring kidney volume. First, it is less invasive than conventional angiography. Second, it can predict the outline of the kidney more accurately. MDCT also makes it easy to differentiate the main vessel, ureter, and the renal parenchymal. Thus, MDCT has advantages because it accurately analyzes the kidney parenchymal volume and represents the actual nephron using volumetric software [10,11]. Accordingly, the relative GFR can be estimated by the relative ratio of the left and right kidney volumes [12]. Although many studies have been conducted to measure eGFR and split renal function by using MDCT, no correlation has been drawn between the imaging used to determine the split kidney function in a live kidney donor during postoperative kidney function [11,13], primarily because the previous reports were too complicated and limited for clinical use. However, we estimated DTPA-eGFR and Vol-eGFR as well as
264 42.29 11.48 122 (46.2) 142 (53.8) 23.4 2.49 240 (90.9) 24 (9.1) 103.62 20.09 52.97 10.32 51.26 10.26
RESULTS
The baseline and demographic characteristics of the live donors included in the study are summarized in Table 1. The study population consisted of 264 live donors, of which 122 donors (46.2%) were male and 142 (53.8%) were female. The mean age of the donors was 42.29 11.48 years, and the follow-up period was 6 months. The mean body mass index of the donors was 23.4 2.49 kg/m2. Among the 264 surgeries, 240 (90.9%) were performed on the left side and 24 (9.1%) were performed on the right side. The mean preoperative eGFR was 103.62 20.09 mL/ min/1.73 m2. The mean DTPA-eGFR and Vol-eGFR values were 52.97 10.32 (mL/min/1.73 m2) and 51.26 10.26 (mL/min/1.73 m2), respectively. The eGFR, which was measured postoperatively in week 1 and in months 1, 3, and 6, exhibited a statistically significant correlation with total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001; Table 2). A significant correlation was likewise detected between DeGFR and total renal volume, DTPA-eGFR, and Vol-eGFR (P < .0001; Table 2). Furthermore, 101 patients had an eGFR <60 mL/min/1.73 m2. Receiver operating characteristic curves were generated to predict the possibility of detecting eGFR <60 mL/min/1.73 m2 at 6 months, using DTPA-eGFR and Vol-eGFR, which revealed that DTPA-eGFR (area under the curve ¼ 0.858; P < .0001) and Vol-eGFR (area under the curve ¼ 0.878; P < .0001) could predict CKD class III at 6 months (Fig 2).
Table 2. Pearson Correlation of MDCT Total Renal Volume (cm3), DTPA-eGFR, Vol-eGFR, and Postoperative eGFR (MDRD) MDCT Total Renal Volume (cm3) Pearson (r2)
Coefficient
MDCT total renal volume 1 DTPA-eGFR 0.102 Vol-eGFR 0.136* Postoperative eGFR (MDRD) (mL/min/1.73 m2) eGFR (MDRD) 1 week 0.253* eGFR (MDRD) 1 month 0.159* eGFR (MDRD) 3 months 0.153* eGFR (MDRD) 6 months 0.192* DeGFR 0.024 *P < .05.
DTPA-eGFR (mL/min/1.73 m2)
Vol-eGFR (mL/min/1.73 m2)
P
Coefficient
P
Coefficient
.079 .019
1 0.949*
.000
1
.000 .008 .015 .005 .693
0.559* 0.685* 0.688* 0.711* 0.268*
.000 .000 .000 .000 .000
0.602* 0.726* 0.711* 0.747* 0.284*
P
Mean SD
329.61 72.10 52.97 10.32 51.26 10.26 .000 .000 .000 .000 .000
57.80 63.90 64.11 65.88 11.94
10.96 11.49 12.16 13.12 8.66
1026
LEE, HAN, KANG ET AL
be eliminated in select patients who have normal renal morphology and size differentiation. Moreover, the current study indicated that Vol-eGFR and DTPA-eGFR demonstrated increased predictive value for CKD class III at 6 months and that Vol-eGFR was a good predictor of renal function recovery. REFERENCES
Fig 2. Prediction of postoperative eGFR <60 mL/min/1.73 m2 at 6 months. The area under the curve (receiver operating characteristic curve) is shown for DTPA-eGFR (area ¼ 0.858; 95% confidence interval, 0.804e0.911; P ¼ .000) and Vol-eGFR (area ¼ 0.878; 95% confidence interval, 0.829e0.928; P ¼ .000).
postoperative eGFRs in live kidney donors by using DTPA and MDCT, which proved to be much easier than the previous report. Our results indicated that MDRD-eGFR was significantly correlated with total renal volume, DTPA-GFR, and Vol-eGFR (Table 2). Also, we predicted the possibility of detecting an eGFR <60 mL/min/1.73 m2 at 6 months by using DTPA-eGFR and Vol-eGFR and determined that the 2 estimated values were a good predictor of CKD class III at 6 months. As well, we confirmed that DTPA-eGFR and Vol-eGFR are significantly correlated with eGFR. Likewise, Vol-eGFR can be used as a prognostic factor of renal function in a live kidney donor; thus, we concluded that MDCT could replace the use of DTPA. CONCLUSIONS
MDRD-eGFR, Vol-eGFR, and DTPA-eGFR were significantly correlated. Hence, we conclude that DTPA scans, which are routinely performed in living kidney donors, could
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