Technetium-99m Mercaptoacetyltriglycine Research Articles

Voiding Sistoüretrogram ile Tanı Konulan Vezikoüreteral Reflü'nün Saptanmasında Dinamik Böbrek Sintigrafisinin Rolü

Aims: This study aims to evaluate the role of standardized dynamic renal scintigraphy (DRS) in recognizing vesicoureteral reflux (VUR) in patients detected with VUR by voiding cystourethrography (VCUG). Methods: The data of all pediatric patients who underwent both VCUG and DRS [technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) or technetium-99m mercaptoacetyltriglycine dynamic renal scintigraphy (Tc-99m MAG-3)] in our hospital between 2013 and 2022 were retrospectively reviewed. Tc-99m MAG-3 was used in infants and Tc-99m DTPA radiopharmaceutical in children over one year old. According to VCUG findings, VUR grades were grouped as grade I-II-III low-grade VUR and IV-V high-grade VUR. The role of DRS in detecting VUR in both low and high-VUR-grade groups was evaluated. Results: A total of 56 patients (and 69 renal units), 23 girls (%41.1), and 33 boys (%68.9) were included in this study. The median value of the time elapsed between the DRS and VCUG examinations was nine days. According to VCUG, VUR was grade I in five renal units, grade II in 19 renal units, grade III in six renal units, grade IV in six renal units, and grade V in 33 renal units. DRS detected VUR in two of 30 renal units (%6.7) in the low VUR grade group. On the other hand, VUR was observed with DRS in 27 of 39 renal units (%69.2) in the high VUR grade group. Conclusions: Standardized DRS shows very low sensitivity in recognizing low-grade VUR, and its performance in detecting high-grade VUR is comparatively better. Raising awareness among clinicians that VUR can be observed with standardized DRS will benefit the patient in terms of early detection of accompanying VUR pathologies.

MP69-12 THE PREDICTION OF RENAL FUNCTION CHANGE AFTER UNILATERAL NEPHROURETERECTOMY IN UPPER TRACT UROTHELIAL CARCINOMA PATIENTS BY USING TC-99M MAG3 RENAL SCAN

You have accessJournal of UrologyCME1 Apr 2023MP69-12 THE PREDICTION OF RENAL FUNCTION CHANGE AFTER UNILATERAL NEPHROURETERECTOMY IN UPPER TRACT UROTHELIAL CARCINOMA PATIENTS BY USING TC-99M MAG3 RENAL SCAN Kai-Sen Su, Yi-Hsiu Huang, Ming-Hsuan Ku, Wei-Ren Chen, Tzu-Hao Huang, Tzu-Chun Wei, I-Shen Huang, Yu-Hua Fan, Chih-Chieh Lin, Tzu-Ping Lin, Hsiao-Jen Chung, Junne-Yih Kuo, Yen-Hwa Chang, Teng-Lung Lin, Jhih-Sian Huang, and Jen-Chieh Chen Kai-Sen SuKai-Sen Su More articles by this author , Yi-Hsiu HuangYi-Hsiu Huang More articles by this author , Ming-Hsuan KuMing-Hsuan Ku More articles by this author , Wei-Ren ChenWei-Ren Chen More articles by this author , Tzu-Hao HuangTzu-Hao Huang More articles by this author , Tzu-Chun WeiTzu-Chun Wei More articles by this author , I-Shen HuangI-Shen Huang More articles by this author , Yu-Hua FanYu-Hua Fan More articles by this author , Chih-Chieh LinChih-Chieh Lin More articles by this author , Tzu-Ping LinTzu-Ping Lin More articles by this author , Hsiao-Jen ChungHsiao-Jen Chung More articles by this author , Junne-Yih KuoJunne-Yih Kuo More articles by this author , Yen-Hwa ChangYen-Hwa Chang More articles by this author , Teng-Lung LinTeng-Lung Lin More articles by this author , Jhih-Sian HuangJhih-Sian Huang More articles by this author , and Jen-Chieh ChenJen-Chieh Chen More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003332.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Radical nephroureterectomy with bladder cuff excision (RNU BCE) is the standard of treatment for high-risk upper tract urothelial carcinoma (UTUC). We aim to develop a predictive equation for post-unilateral RNU BCE renal function by using pre-operative renal scintigraphy. METHODS: From January 2010 to December 2020, patients diagnosed with UTUC and underwent unilateral RNU BCE in our institute were reviewed. Comprehensive renal function evaluation by technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renal scintigraphy was done pre-operatively. Serum creatinine level was recorded pre-operatively, 3 months (3M) and 6 months (6M) post-operatively (OP). Pearson’s linear correlation analysis was used for developing predictive equation. Internal validation with patients of the same criteria recruited after the study period (2021’s database) was done to test the equation’s accuracy. Cisplatin ineligibility by renal function was defined as eGFR <60 ml/min/1.73m2. RESULTS: In total, 487 patients who underwent unilateral RNU BCE for UTUC were included. The median pre-operative total effective renal plasma flow (ERPF) was 241.30 ml/min, and the lesion side accounted for 35.6% of total ERPF. Pre-operative lesion side ERPF ratio was significantly associated to post-operative decrease of eGFR ratio at 3 months (R=0.613, p<0.001), and the predictive equation was established as: Post-OP 3M Decrease of eGFR (%)=0.675 x Lesion Side/Total ERPF Ratio (%)+0.919. Internal validation with 2021’s database showed high accuracy of prediction in post-OP 3M eGFR decrease (R=0.896). For the 12 patients that experienced RNU-related cisplatin ineligibility, our predictive equation successfully foresaw such renal function loss in all patients, with a prediction accuracy of 12/12 (100%). CONCLUSIONS: We established a predictive equation using pre-operative lesion side ERPF ratio to predict post-operative eGFR loss. Such an equation could accurately predict residual renal function and foresee RNU-related cisplatin ineligibility before unilateral RNU. Source of Funding: The authors declare that they have no conflicts of interest related to the subject matter or materials discussed in this article © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e968 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kai-Sen Su More articles by this author Yi-Hsiu Huang More articles by this author Ming-Hsuan Ku More articles by this author Wei-Ren Chen More articles by this author Tzu-Hao Huang More articles by this author Tzu-Chun Wei More articles by this author I-Shen Huang More articles by this author Yu-Hua Fan More articles by this author Chih-Chieh Lin More articles by this author Tzu-Ping Lin More articles by this author Hsiao-Jen Chung More articles by this author Junne-Yih Kuo More articles by this author Yen-Hwa Chang More articles by this author Teng-Lung Lin More articles by this author Jhih-Sian Huang More articles by this author Jen-Chieh Chen More articles by this author Expand All Advertisement PDF downloadLoading ...

Delivery of sorafenib by myofibroblast-targeted nanoparticles for the treatment of renal fibrosis.

Fibrosis is an excessive accumulation of the extracellular matrix within solid organs in response to injury and a common pathway that leads functional failure. No clinically approved agent is available to reverse or even prevent this process. Herein, we report a nanotechnology-based approach that utilizes a drug carrier to deliver a therapeutic cargo specifically to fibrotic kidneys, thereby improving the antifibrotic effect of the drug and reducing systemic toxicity. We first adopted in vitro-in vivo combinatorial phage display technology to identify peptide ligands that target myofibroblasts in mouse unilateral ureteral obstruction (UUO)-induced fibrotic kidneys. We then engineered lipid-coated poly(lactic-co-glycolic acid) nanoparticles (NPs) with fibrotic kidney-homing peptides on the surface and sorafenib, a potent antineoplastic multikinase inhibitor, encapsulated in the core. Sorafenib loaded in the myofibroblast-targeted NPs significantly reduced the infiltration of α-smooth muscle actin-expressing myofibroblasts and deposition of collagen I in UUO-treated kidneys and enhanced renal plasma flow measured by Technetium-99m mercaptoacetyltriglycine scintigraphy. This study demonstrates the therapeutic potential of the newly identified peptide fragments as anchors to target myofibroblasts and represents a strategic advance for selective delivery of sorafenib to treat renal fibrosis. SIGNIFICANCE STATEMENT: Renal fibrosis is a pathological feature accounting for the majority of issues in chronic kidney disease (CKD), which may progress to end-stage renal disease (ESRD). This manuscript describes a myofibroblast-targeting drug delivery system modified with phage-displayed fibrotic kidney-homing peptides. By loading the myofibroblast-targeting nanoparticles (NPs) with sorafenib, a multikinase inhibitor, the NPs could suppress collagen synthesis in cultured human myofibroblasts. When given intravenously to mice with UUO-induced renal fibrosis, sorafenib loaded in myofibroblast-targeting NPs significantly ameliorated renal fibrosis. This approach provides an efficient therapeutic option to renal fibrosis. The myofibroblast-targeting peptide ligands and nanoscale drug carriers may be translated into clinical application in the future.

The Delayed Nephrogram: Point-of-care Quantitative Measurement, Validation as an Indicator of Obstruction, and Novel Use as a Predictor of Renal Functional Impairment

BackgroundThe diagnostic value of delayed nephrograms on contrast-enhanced computed tomography has not been studied rigorously. ObjectiveTo develop a method for quantitatively assessing delayed and diminished nephrograms (DDNs) easily at the point of care and to assess the association of DDNs with renal obstruction and renal function. Design, setting, and participantsData were reviewed from 76 patients who underwent a contrast-enhanced computed tomography scan within 30 days of a technetium-99m mercaptoacetyltriglycine diuretic renal scintigraphy (MAG3-DRS) which showed at least one kidney to have normal drainage (T1/2 <10 min) between 2010 and 2021 at a tertiary academic center. Outcome measurements and statistical analysisAttenuations of the renal cortex and medulla were measured using circular regions of interest. These attenuations were compared between kidneys to compute several measures of DDN in the kidney with a greater concern for obstruction. Renal parenchymal volume and anterior-posterior renal pelvis diameter (APD) were estimated using simple linear measurements. Inter-rater reliability was computed using the intraclass correlation coefficient (ICC), correlations were computed using Spearman’s R, and the relationships between DDN, APD, and renal function of the subject kidney were estimated using linear regression. Results and limitationsMeasures of DDN were highly reliable between raters (ICC 0.71–0.87). DDN was almost always associated with prolonged drainage on MAG3-DRS (90–100%); however, 33–52% of patients with prolonged drainage on MAG3-DRS had no appreciable DDN, depending on the measure of the DDN chosen. All measures of DDN were associated with decreased renal function (<0.001). APD did not significantly predict renal function when controlling for a DDN. ConclusionsDDNs on contrast-enhanced computed tomography are associated with renal obstruction and can easily and accurately be quantified at the point of care. A DDN is more closely associated with renal dysfunction than renal pelvic dilation and therefore may be useful in assessing the severity of upper tract obstruction. Patient summaryIn this report, we confirm that a “delayed nephrogram”, a classic x-ray finding thought to be associated with kidney blockage, is associated with blockage of the affected kidney. Furthermore, we show that a delayed nephrogram indicates that the affected kidney is not functioning as well as we would expect for a normal kidney of the same size. Since the severity of a delayed nephrogram predicts this decreased function better than the degree of dilation of the kidney, which is a different measurement often used to measure the severity of kidney blockage, the delayed nephrogram may be a better way of measuring the severity of kidney blockage in clinical practice.

Comparison between Tc-99m DTPA and Tc-99m MAG3 Renal Scintigraphy for Prediction of Early Adverse Outcome After Kidney Transplantation.

Renal scintigraphy (RS) with either technetium-99m diethylene-triamine-pentaacetate (Tc-99m DTPA) or technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) has both been used to evaluate early allograft function after kidney transplantation (KT). This study was done to compare the predictive performance of RS using these two radiopharmaceuticals for prediction of outcomes during first 3months of KT. This retrospective study included patients who received KT then underwent both Tc-99m DTPA and Tc-99m MAG3 RS, successively. Receiver operating characteristic (ROC) curve analysis was used to determine the predictiveness of RS parameters on early clinical adverse outcomes of either (1) graft-related death, (2) need for graft resection, (3) delayed graft function requiring temporary dialysis, or (4) a serum creatinine level of ≥ 2.0mg/dL at three months post-KT, as well as to predict biopsy-confirmed acute tubular necrosis and acute rejection. Of 187 patients included, 77 (41.2%) had at least one early adverse clinical outcome. Tc-99m MAG3 RS was more predictive than Tc-99m DTPA RS, in terms of AUCROC, in three parameters including time to peak (0.754 vs. 0.516, p-value 0.0001), 20-min to peak ratio (0.762 vs. 0.651, p-value 0.006), and 20-min to 3-min ratio (0.823 vs. 0.699, p-value 0.0005). Acute tubular necrosis was better predicted by Tc-99m MAG3 RS while both were at best only modest in predicting acute rejection. Three parameters which, when obtained from Tc-99m MAG3 RS, had superior predictiveness compared with Tc-99m DTPA RS, including time to peak, 20-min to peak ratio, and 20-min to 3-min ratio.

Transferability of a two-strip method for the quality control of technetium-99m mercaptoacetyltriglycine ([99mTc]Tc-MAG3)

ObjectivesTechnetium-99m mercapto-acetyl-triglycine ([99mTc]Tc-MAG3) is a radiopharmaceutical diagnostic agent used in nuclear medicine intended for the exploration of nephrological and urological disorders. Patient safety and reliability of this imaging procedure especially...

177Lu-PSMA-617 Therapy in Mice, with or without the Antioxidant α1-Microglobulin (A1M), Including Kidney Damage Assessment Using 99mTc-MAG3 Imaging.

Anti-prostate specific membrane antigen (PSMA) radioligand therapy is promising but not curative in castration resistant prostate cancer. One way to broaden the therapeutic index could be to administer higher doses in combination with radioprotectors, since administered radioactivity is kept low today in order to avoid side-effects from a high absorbed dose to healthy tissue. Here, we investigated the human radical scavenger α1-microglobulin (A1M) together with 177-Lutetium (177Lu) labeled PSMA-617 in preclinical models with respect to therapeutic efficacy and kidney toxicity. Nude mice with subcutaneous LNCaP xenografts were injected with 50 or 100 MBq of [177Lu]Lu-PSMA-617, with or without injections of recombinant A1M (rA1M) (at T = 0 and T = 24 h). Kidney absorbed dose was calculated to 7.36 Gy at 4 days post a 100 MBq injection. Activity distribution was imaged with Single-Photon Emission Computed Tomography (SPECT) at 24 h. Tumor volumes were measured continuously, and kidneys and blood were collected at termination (3–4 days and 3–4 weeks after injections). In a parallel set of experiments, mice were given [177Lu]Lu-PSMA-617 and rA1M as above and dynamic technetium-99m mercaptoacetyltriglycine ([99mTc]Tc-MAG3) SPECT imaging was performed prior to injection, and 3- and 6-months post injection. Blood and urine were continuously sampled. At termination (6 months) the kidneys were resected. Biomarkers of kidney function, expression of stress genes and kidney histopathology were analyzed. [177Lu]Lu-PSMA-617 uptake, in tumors and kidneys, as well as treatment efficacy did not differ between rA1M and vehicle groups. In mice given rA1M, [99mTc]Tc-MAG3 imaging revealed a significantly higher slope of initial uptake at three months compared to mice co-injected with [177Lu]Lu-PSMA-617 and vehicle. Little or no change compared to control was seen in urine albumin, serum/plasma urea levels, RT-qPCR analysis of stress response genes and in the kidney histopathological evaluation. In conclusion, [99mTc]Tc-MAG3 imaging presented itself as a sensitive tool to detect changes in kidney function revealing that administration of rA1M has a potentially positive effect on kidney perfusion and tubular function when combined with [177Lu]Lu-PSMA-617 therapy. Furthermore, we could show that rA1M did not affect anti-PSMA radioligand therapy efficacy.

Effect of Verapamil on Kidney Function Using Radionuclide Imaging

Background and Objective: Calcium channel blockers (CCBs) are among the most widely used prescribed drugs for the treatment of cardiovascular diseases. The present study investigates the effect of verapamil, which is most commonly used as a CCB, on kidney function using radionuclide imaging. Methods: Ten New Zealand white rabbits were used in vitro (4) and in vivo (6) studies. Isometric tensions were recorded for isolated renal artery ring segments, while renographic studies were performed using Technetium-99m mercaptoacetyltriglycine and Gamma camera. Time to peak activity (Tmax) and time from peak to 50% activity (T1/2), were calculated from the renograms for control and treated rabbits with verapamil. Results: In vitro, verapamil shifted the curve of phenylephrine concentration-dependent contraction on renal artery to the right, and decrease the highest contraction by 30 ± 3%. In vivo, the average values of Tmax for control and treated rabbits were 2.8 ± 0.1 and 2.2 ± 0.2 min respectively. The T1/2 for control and treated rabbits were 4.7 ± 0.05 and 4.2 ± 0.08 min respectively. The differences were statistically significant: p < 0.05. There is 30 ± 4% decrease in the 2 values. This indicates that there is a rapid renal uptake of the tracer and clearance of the radioactivity after verapamil. Conclusion: Verapamil dilates the renal artery and accelerates both the Tmax and T1/2 in the renogram. It increases renal blood perfusion and protects kidney function and therefore improves its work. However, verapamil should not be used while performing renograms to avoid misleading results.

Minimally-Invasive Ureteral Reconstruction for Ureteral Complications of Kidney Transplants

ObjectiveTo present the technique, feasibility and results of minimally-invasive reconstruction of the transplanted ureter using the native ipsilateral ureter in post-transplant ureteral strictures and vesicoureteral reflux (VUR) causing graft pyelonephritis. Ureteral complications after kidney transplantation represent a significant cause of morbidity potentially leading to graft dysfunction or loss. MethodsA prospective database from October 2011 to August 2018 identified renal transplant recipients who underwent minimally-invasive pyeloureterostomies or ureteroureterostomies using the ipsilateral ureter. Indications for either transplant ureteral stricture or VUR correction were assessed. Preoperative evaluation included a technetium-99m mercaptoacetyltriglycine renal scan to assess residual native renal function and either a video cysto-urethrogram or cystoscopy and retrograde pyelography. Postoperative patency was evaluated with either cystograms or antegrade nephrograms in conjunction with a technetium-99m mercaptoacetyltriglycine study. ResultsSeven patients were followed with a mean follow-up time of 20.9 months (range 4.7-64.8 months). Three cases of VUR causing graft pyelonephritis and 4 cases of transplant ureteral stricture were identified. Five minimally-invasive transplant-to-native pyeloureterostomies and 2 transplant-to-native ureteroureterostomies were performed. Six cases were performed robotically and 1 laparoscopically. No recurrent episodes of pyelonephritis were observed for patients treated for VUR causing graft pyelonephritis. Postoperative renal scans and contrast studies demonstrated no evidence of obstruction or urinary leaks in all cases. ConclusionMinimally-invasive reconstruction of the transplant ureter by pyeloureterostomy or ureteroureterostomy using the ipsilateral native ureter is feasible and can be safely performed with graft survival and acceptable complication rates.

A new two-strip TLC method for the quality control of technetium-99m mercaptoacetyl-triglycine (99mTc-MAG3)

Background99mTc-mercaptoacetyl-triglycine (99mTc-MAG3) has been used for dynamic renal imaging since about 30 years. Free pertechnetate (99mTcO4), colloidal 99mTc ((99mTcO2)n), 99mTc-tartrate (precursor), precomplexes (99mTc-(MAG3)x) and lipophilic 99mTc-MAG2 are the main radiochemical impurities that may occur in the preparation. The total amount of these impurities has to be identified before release of the product for patient administration to guarantee patient safety and good image quality. The European Pharmacopoeia suggests a method based on high-pressure liquid chromatography analysis in combination with a paper chromatography. This analytical method is time consuming, expensive and requires specially trained technicians. As a consequence, it is not widely applied in nuclear medicine radiopharmacies.ResultsWe developed a simple method for radiochemical purity testing of 99mTc-MAG3. The method is based on thin layer chromatography with two strips to be developed in parallel. Method validation was carried out in comparison to the official methods of the companies and to the European Pharmacopoeia method. It was tested on specificity, accuracy, robustness and precision.ConclusionThe proposed method is able to identify and quantify the sum of all impurities occurring in the preparation, respecting the acceptance criteria for the radiochemical purity defined by the official methods. Hydrophilic and lipophilic compounds are identified separately and results are obtained within less than 20 minutes. Our method is simple, cost effective, fast and is suitable for employing dose calibrators or radiometric scanners.

A review of paediatric administered radiopharmaceutical activities to determine compliance with prescription guidelines.

Attempts are underway to standardize paediatric administered activities, but equally important is knowing the actual activities administered to patients. In this work, paediatric administered activities are reviewed to determine compliance with the institution-prescribed guidelines. Paediatric administered activities for common studies at our institution, August 2011 to January 2017, have been analysed to determine their deviations from the set guideline tolerance of 10% from prescribed activities. The results for technetium-99m hydroxy diphosphonate (Tc-HDP), technetium-99m mercaptoacetyl triglycine (Tc-MAG3) and technetium-99m dimercaptosuccinic acid (Tc-DMSA), are presented here. Tc-MAG3 mean activities were close to the tolerance guideline at 10.3% SD. For Tc-HDP and Tc-DMSA, the prescribed guidelines were reviewed and reduced in May 2014 and September 2015, respectively. SDs for these studies over the two acquisition periods were different (8.9 and 6.6%, respectively, for Tc-HDP and 11.8 and 14.2%, respectively, for Tc-DMSA).The administered activities (dispensed minus residual activities) to patients depend on prescribed activities and dispensing and injecting techniques. Deviations from the prescribed activities are primarily because of issues related to residual activities, particularly with small activities prescribed in young patients. Small activities in small volumes make residual activities significant. The skill and experience of the nuclear medicine staff are essential in minimizing deviations from prescribed activities. It is important to measure residual to accurately determine the administered activities. If precautions are taken with dispensing and injecting techniques, it is possible to administer activities close to 10% of the prescribed activities. The regular review of the administered activities is essential to ensure that patients are not unnecessarily irradiated.

Interobserver agreement on cortical tracer transit in 99mTc-MAG3 renography applied to congenital hydronephrosis.

This study aims to evaluate interobserver agreement on visual analysis of technetium-99m mercaptoacetyltriglycine (Tc-MAG3) renal tissue transit used for the evaluation of antenatal hydronephrosis. Thirty-eight Tc-MAG3 diuretic renograms were retrospectively collected between 1 and 31 December 2015. The 1-min reframed images were presented to four nuclear medicine consultants and to two nuclear medicine residents, one in the first year of the training program and the others in their fourth and final year. These observers were asked to classify the radiotracer cortical transit (normal/delayed) based solely on visual assessment of the images. For the interobserver agreement, modified Fleiss' kappa (κ) analysis for multiple raters was carried out. For both groups, percentages of agreement were also calculated. A total of 69 kidneys were evaluated. All four nuclear medicine consultants agreed on the classification of 88.4% of the kidneys. When the agreement of at least three of the four observers was considered, the percentage of agreement reached 98.6%. The two nuclear medicine residents agreed on the classification of 69.6% of the kidneys. The modified Fleiss' κ-value was 0.88 (95% confidence interval: 0.79-0.95) for the group of nuclear medicine consultants, indicating almost perfect agreement. For the residents, it was 0.39 (95% confidence interval: 0.16-0.59), suggesting fair agreement. Our results seem to indicate that there is an almost perfect agreement in the qualitative identification of delayed cortical transit among physicians with experience at observing renographic images.

The correlation between preoperative renal scintigraphy and postoperative renal function in upper urinary tract urothelial carcinoma patients following radical nephroureterectomy

ObjectiveTo predict the renal function after nephroureterectomy (NUR) for upper urinary tract urothelial cancer (UTUC) based on preoperative technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) renal scintigraphy. Subjects and methodsWe retrospectively reviewed 238 patients who originally underwent nephroureterectomy for UTUC between 2007 and 2010. Of these patients, 129 underwent MAG3 renal scintigraphy before unilateral NUR. Serum creatinine was measured in all of the patients before surgery, and renal function was monitored for one year after surgery. Preoperative and postoperative eGFRs were compared and analyzed based on the preoperative MAG3 renal scintigraphy. ResultsA total of 129 patients, including 62 men (48%) and 67 women (52%) with an average age at surgery of 69.0 years (range from 48 to 87) were included in this study. The mean preoperative creatinine level was 1.42 mg/dL, and the baseline eGFR was 54.76 ml/min/1.73 m2. One year after NUR, the mean creatinine level was 1.89 mg/dL, and the eGFR was 44.44 ml/min/1.73 m2, a mean decrease of 18.73%. The preoperative effective renal plasma flow (ERPF) of the operated kidney was 91.65 ml/min/1.73 m2, and that of the remaining kidney 158.30 ml/ min/1.73 m2. The average preoperative ERPF of the resected kidney accounted for 34% of total preoperative ERPF, which was statistically significant in its relation to the decrease in eGFR. The decrease in eGFR ratio was also significantly correlated with the calculated decrease in ERPF ratio (R2 = 0.279, p < 0.001). The predictive equation of renal function one year after NUR was established as following: eGFR decreased ratio = –0.80 × predictive ERPF decreased ratio +0.72. ConclusionWe developed an equation to predict postnephroureterectomy 1 year eGFR before surgery based on preoperative MAG3 renal scintigraphy results and preoperative eGFR. The equation could be more accurate in the situation if the diseased kidney is not hydronephrotic.

Usefulness of Three-Dimensional Computerized Tomographic Volumetry for Determining Split Renal Function in Donors for Living-Related Kidney Transplantation

BackgroundIn living-related kidney transplantation, it is important to spare the superior kidney for the donor if there is a significant difference in split renal function. We have been using renal scintigraphy to decide which kidney to be donated. Recently, we used data regarding kidney volume and maximum area in the frontal plane of the 3-dimensional computerized tomography (3DCT) image of the kidney. We evaluated the validity of these parameters for estimating split renal function. MethodsWe calculated the ratio of right kidney volume (VOL-ratio) and maximum area in the frontal plane of the kidney (AREA-ratio) with the use of 3DCT and examined the correlation between these 2 parameters and the ratio of right kidney estimated renal plasma flow (ERPF-ratio) calculated with the use of technetium-99m mercaptoacetyltriglycine (99mTc-MAG3) renal scintigraphy. Forty-six donors for living-related kidney transplantation were evaluated. Their mean age was 53 years; there were 14 male and 32 female donors. ResultsCorrelation coefficients between VOL-ratio and ERPF-ratio and between AREA-ratio and ERPF-ratio were 0.441 and 0.471, respectively (P = .002; P = .001). Bland-Altman analysis confirmed that the majority of difference scores between VOL-ratio–ERPF-ratio and AREA-ratio–ERPF-ratio were within the 95% confidence interval of the differences. The differences between VOL-ratio–ERPF-ratio and AREA-ratio–ERPF-ratio were (mean ± 1.96SD) 1.17 ± 6.04% and −0.82 ± 6.09%, respectively. It seemed that the distribution of AREA-ratio–ERPF-ratio was less biased than that of VOL-ratio–ERPF-ratio. ConclusionsThe discrepancy between the ratio of kidney volume and the maximum area in the frontal plane of the kidney may have been due to the rotation of the kidney. The ratio of ERPF obtained with the use of renal scintigraphy approximates not only the ratio of kidney volume but also the ratio of maximum area in the frontal plane of the kidney. Thus, our findings suggest that the use of 99mTc-MAG3 renal scintigraphy alone may underestimate the function of a rotated kidney.

Late ureteral obstruction after endoscopic treatment of vesicoureteral reflux with polyacrylate polyalcohol copolymer.

To investigate the incidence and presentation of ureteral obstruction after endoscopic injection of polyacrylate polyalcohol copolymer (PPC) for the treatment of vesicoureteral reflux, and to analyze its possible causes, together with histopathologic assessment. The data of 189 patients who underwent endoscopic injection of PPC between May 2011 and December 2013 were retrospectively reviewed. After the injection, patients were followed up by urinalysis and ultrasonography monthly for 3 months. Control voiding cystouretrography was performed in the third postoperative month. Patients were then followed up by ultrasound every 3 months. If a new-onset hydroureteronephrosis (HUN) was observed, control ultrasound was performed monthly to follow the change in the degree of HUN. If a moderate or severe HUN was observed, technetium-99m mercaptoacetyltriglycine or dimercaptosuccinic acid scintigraphy was performed. For patients who needed open surgery, Cohen ureteroneocystostomy was performed. The distal 1 cm of the ureters was resected and examined histopathologically. One hundred eighty-nine patients with 268 refluxing ureters underwent endoscopic injection of PPC. Ureteral obstruction was observed in 3 ureters (1.1%), in 3 female patients of whom the degrees of reflux were grade 4, 5, and 5, respectively. Obstruction showed late onset in all 3 patients. Manifestations of obstruction included pain in 2 patients and recurrent febrile urinary tract infection with loss of function in scintigraphy in 1. All 3 patients underwent open ureteroneocystostomy. PPC may cause ureteral obstruction several months or even years after injection. Patients who undergo endoscopic treatment of PPC need long-term follow-up, despite reflux showing complete resolution.

Effect of sulfa drugs on kidney function and renal scintigraphy

The sulfonamide group is widely used for bacterial diseases including kidney and urinary tract infections. The present study investigates the effect of a sulfa drug on kidney function and renography studies by using a radionuclide. Renography studies were performed on New Zealand white rabbits. Each rabbit was injected with 48.1 MBq technetium-99m mercaptoacetyltriglycine ((99m) Tc-MAG-3). Dynamic images were acquired using a gamma camera. Radioactivity time curves were generated from the regions of interest, time to peak activity (Tmax ) and time from peak to 50% activity (T1/2 ). Each rabbit served as its own control. The sulfa drug was given to these rabbits for 7 days (i.v injection 130 mg/kg daily in two divided doses; i.e. the single dose is 65 mg/kg), then dynamic images were acquired. Treatment with sulfa shifted the experimental curves to the right of the control curves. This result showed that there was a delayed renal uptake of (99m) Tc-MAG-3 and its clearance. Calculated averages of Tmax were 2.2 ± 0.3 and 5.9 ± 0.5 min; while for T1/2 were 3.1 ± 0.3 and 8.4 ± 0.6 min for control and sulfa-treated rabbits, respectively (n = 20; P < 0.05). Our results indicate that sulfa drug induced pharmacokinetic changes because of delaying both the Tmax and T1/2 . Sulfa drug has an effect on the reabsorption from the renal tubules and the excretion process of (99m) Tc-MAG-3 which is excreted almost exclusively by the renal tubules. Therefore, sulfa drug causes a deterioration in kidney function and an alteration on radionuclide renography.

Evaluation of interobserver variability of parenchymal phase of Tc-99m mercaptoacetyltriglycine and Tc-99m dimercaptosuccinic acid renal scintigraphy.

Objective:The aim of this study was to investigate the variability in the interpretation of parenchymal abnormalities and to assess the differences in interpretation of routine renal scintigraphic findings on posterior view of technetium-99m dimercaptosuccinic acid (pvDMSA) scans and parenchymal phase of technetium-99m mercaptoacetyltriglycine (ppMAG3) scans by using standard criterions to make standardization and semiquantitative evaluation and to have more accurately correlation.Materials and Methods:Two experienced nuclear medicine physicians independently interpreted pvDMSA scans of 204 and ppMAG3 scans of 102 pediatric patients, retrospectively. Comparisons were made by visual inspection of pvDMSA scans, and ppMAG3 scans by using a grading system modified from Itoh et al. According to this, anatomical damage of the renal parenchyma was classified into six types: Grade 0-V. In the calculation of the agreement rates, Kendall correlation (tau-b) analysis was used.Results:According to our findings, excellent agreement was found for DMSA grade readings (DMSA-GR) (tau-b = 0.827) and good agreement for MAG3 grade readings (MAG3-GR) (tau-b = 0.790) between two observers. Most of clear parenchymal lesions detected on pvDMSA scans and ppMAG3 scans identified by observers equally. Studies with negative or minimal lesions reduced correlation degrees for both DMSA-GR and MAG3-GR.Conclusion:Our grading system can be used for standardization of the reports. We conclude that standardization of criteria and terminology in the interpretations may result in higher interobserver consistency, also improve low interobserver reproducibility and objectivity of renal scintigraphy reports.

An incidental detection of aortic aneurysm on Tc-99m MAG3 renal scintigraphy

A 71-year-old man with newly diagnosed hypertension was referred for Technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renal scintigraphy to evaluate the recent onset of impairment in renal functions. Dynamic imaging revealed activity flow which was suspicious for aortic aneurysm (AA) with a concurrent decrease in left renal blood flow. CT angiography of the thoracoabdominal aorta confirmed that this area corresponded to AA. The purpose of this report was to present the first case of incidental detection of AA on Tc-99m MAG3 scintigraphy and highlight the importance of correlative imaging for the diagnosis of abnormal radioactivity accumulation in the region of vascular structures.

Renal Scintigraphy in the Acute Care Setting

Renal scintigraphy is a powerful imaging method that provides both functional and anatomic information, which is particularly useful in the acute care setting. In our institution, for the past 2 decades, we have used a 25-minute renal diuretic protocol, technetium-99m ((99m)Tc) mercaptoacetyltriglycine with simultaneous intravenous injection of furosemide, for all ages and indications, including both native and transplant kidneys. As such, this protocol has been widely used in the workup of acutely ill patients. In this setting, there are common clinical entities which affect patients with native and transplant kidneys. In adult patients with native kidneys one of the most frequent reasons for emergency room visits is renal colic due to urolithiasis. Although unenhanced computed tomography is useful to assess the anatomy in cases of renal colic, it does not provide functional information. Time zero furosemide renal scintigraphy can do both and we have shown that it can effectively stratify patients with renal colic. To this end, 4 characteristic patterns of scintirenography have been identified, standardized, and consistently applied: no obstruction, partial obstruction (mild vs high grade), complete obstruction, and stunned (postdecompressed) kidney. With the extensive use of this protocol over the past 2 decades, a pattern of "regional parenchymal dysfunction" indicative of acute pyelonephritis has also been delineated. This information has proved to be useful for patients presenting with urinary tract infection and suspected pyelonephritis, as well as for patients who were referred for workup of renal colic but were found to have acute pyelonephritis instead. In instances of abdominal trauma, renal scintigraphy is uniquely suited to identify urine leaks. This is also true in cases of suspected leak following renal transplant or from other iatrogenic/postsurgical causes. Patients presenting with acute renal failure can be evaluated with renal scintigraphy. A scintigraphic pattern of "relative preservation of flow as compared to function" has been identified as indicative of acute tubular necrosis, which is distinct from other potential causes of acute renal failure, such as nephrotoxicity and in the case of renal transplants, rejection.

Native renal function after combined liver-kidney transplant for type 1 hepatorenal syndrome: initial report on the use of postoperative Technetium-99 m-mercaptoacetyltriglycine scans

Type 1 hepatorenal syndrome (HRS) is characterized by rapid deterioration of renal function. We sought to assess native kidney function after combined kidney-liver transplant (CLKTx) performed for type 1 HRS. We performed a retrospective, cross-sectional, single-center study. All patients with Type 1 HRS who received a CLKTx at the University of California, San Francisco from 1997 to 2007 were screened for enrollment. Patients with a baseline estimated glomerular filtration rate (eGFR) ≥30ml/min/1.73m(2) were eligible. Twenty-three patients were identified and consented to receive a Technetium-99 m-mercaptoacetyltriglycine (MAG3) nuclear scan to measure the native kidney contribution to overall renal function. Only 4 of the 23 subjects (17.4%) demonstrated native renal function that consisted of a contribution ≥50% of total renal function. Several factors and comorbidities such as age, gender, race, duration of HRS, need for and duration of renal replacement therapy, need for pressors, urine sodium, proteinuria, and use of octreotide/midodrine were analyzed and not found to be significant in predicting native renal function. The assessment of post-transplant native renal function following CLKTx may allow for improved accuracy in identifying the patients in need of CLKTx, and thus allow for greater optimization of dual-organ allocation strategies in patients with concomitant liver and renal failure.