technetium-tc-99m-ethylenedicysteine and Kidney-Diseases

Search for the ideal radiopharmaceutical to measure effective renal plasma flow (ERPF) has been underway since the early 1960s. Although ortho-iodohippuran (OIH) has biological properties suited for measurement of ERPF, the imaging characteristics are less than desirable. With the advent of the molybdenum-99/technetium-99m generators, efforts have focused on the development of a technetium-99m agent to measure ERPF. Over the last 10 to 15 years several promising technetium-99m renal imaging agents have been developed. Early examples of technetium-99m renal agents such as 99mTc-CO2DADS and 99mTc-PAHIDA, although not ideal replacements for OIH, demonstrated that a technetium-99m complex could be actively transported by the renal tubules and provided the impetus for development of new technetium-99m renal agents. The next breakthrough in technetium-99m renal agents was the development of the triamide mercaptide class of chelating agents by Fritzberg et al. To date the most promising compound in this class is mercaptoacetyltriglycine (MAG3). 99mTc-MAG3 is currently the agent of choice, but it is by no means the perfect replacement for OIH. Problems with high plasma protein binding and clearances that are only 50% to 60% of the OIH clearance make measurement of ERPF difficult. The serendipitous discovery that metabolites of the brain agent 99mTc-ethylenedicysteine diethylester (99mTc-L,L-ECD) are rapidly excreted in the urine has led to the evaluation of 99mTc-L,L-ethylenedicysteine (99mTc-L,L-ECD) as a potential renal imaging agent. Studies that have evaluated 99mTc-L,L-EC in animals, normal human volunteers, and patients with various renal disorders reveal that the renal clearance of 99mTc-L,L-EC is higher than 99mTc-MAG3 and more closely approaches that of OIH. Other approaches that are being examined in the development of the ideal renal imaging agent include substitution of various amino acids for glycine residue in MAG3 and technetium-99m labeled organic cations.

Topics: Animals; Cysteine; Humans; Kidney; Kidney Diseases; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Renal Plasma Flow, Effective; Technetium Tc 99m Mertiatide

This study was performed to evaluate the effectiveness of technetium-99m N,N-ethylenedicysteine (Tc-99m EC) in comparison to technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy. Differential renal function (DRF) was calculated by both methods and the cortical-phase images of dynamic Tc-99m EC scintigraphy were evaluated for parenchymal defects.. A total of 62 patients with various kidney disorders ranging in age from 1 to 44 years underwent both Tc-99m DMSA and Tc-99m EC scintigraphy. Tc-99m EC summed images of the cortical phase and Tc-99m DMSA images were evaluated visually and quantitatively. Visual analysis was used to define renal parenchymal abnormalities. Quantitative analysis was used in the calculation of DRF. The Tc-99m DMSA scan was taken as the gold standard, and the summed Tc-99m EC scan findings were compared against it.. The images obtained with Tc-99m DMSA and Tc-99m EC scintigraphy revealed 99 and 97 focal defects, respectively. The 2 renal parenchyma defects located in the ventral middle sections remained undetected with Tc-99m EC scintigraphy. DRF of the kidneys in each patient was compared using both radiopharmaceuticals. Highly positive correlation between the differential function of these 2 investigations was found (R = 0.91, P = 0.001). The values of mean DRF of the left kidney on Tc-99m EC and Tc-99m DMSA images were 45.8 +/- 19.1 and 45.0 +/- 20.4, respectively. There were no significant differences (P > 0.05).. This study suggests that although Tc-99m DMSA scintigraphy remains the gold standard method for evaluating parenchymal abnormalities, Tc-99m EC scintigraphy can be a reliable single-modality study to evaluate renal cortical defects, DRF, perfusion, drainage of the urinary system, and indirect evidence of vesicoureteric reflux with the added advantage of low radiation exposure to the patient.

Topics: Adolescent; Adult; Child; Child, Preschool; Cysteine; Female; Humans; Infant; Kidney Diseases; Male; Organotechnetium Compounds; Radioisotope Renography; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Dimercaptosuccinic Acid

To evaluate whether cortical scars can be detected using the summed images of technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC) renal dynamic scan, and to compare the results with technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) scan. To evaluate the inter-observer variability for 99mTc-L,L-EC and 99mTc-DMSA scan reporting.. One hundred and three patients were initially included in the study; 21 were excluded, five due to a single functioning kidney and 16 due to impaired renal function (serum creatinine>2.5 mg.dl(-1)). Eighty-two patients (39 females, 43 males), including 31 children, with a mean age of 33.4+/-11.3 years (range, 4 months to 74 years), underwent both 99mTc-DMSA and 99mTc-L,L-EC scintigraphy within a period of 14 days. 99mTc-L,L-EC images were regrouped into 2 min image sets, and the initial 2 min summed image (cortical phase) was used for the evaluation of scars. Three independent observers analysed both images separately on different days without being aware of the identity and clinical details of the patients. Their 99mTc-L,L-EC findings were compared with the consensus 99mTc-DMSA scan findings taken as reference.. The overall sensitivity of 99mTc-L,L-EC scans was 93% and the specificity was 96%. The inter-observer variability was 0.91 for 99mTc-L,L-EC and 0.94 for 99mTc-DMSA scan reporting, using the weighted kappa analysis at P<0.05.. 99mTc-L,L-EC is an excellent single-modality comprehensive investigational agent for renal morphology, function and outflow tract evaluation with the added advantages of lower cost, convenience and low radiation exposure to the patient.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Child, Preschool; Cicatrix; Cysteine; Female; Humans; Infant; Kidney Diseases; Kidney Function Tests; Male; Middle Aged; Organotechnetium Compounds; Radioisotope Renography; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Single-Blind Method; Technetium Tc 99m Dimercaptosuccinic Acid

Technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) as a static renal agent is currently the most frequently used agent in the detection of renal scarring, and allows accurate calculation of differential renal function (DRF). But this agent has some disadvantages such as relatively higher radiation dose and time consumption.. The purpose of this study was to evaluate the potential of summed image that obtained from parenchymal phase of the dynamic technetium-99m-N,N-ethylenedicysteine (Tc-99m EC) scintigraphy in the detection of renal parenchymal defects and in the estimation of DRF, and to compare the results of this method with those of Tc-99m DMSA scintigraphy. The uptake ratios of the kidney to body background were also calculated for these two methods. Twenty-nine children with various renal disorders underwent both static Tc-99m DMSA and dynamic Tc-99m EC scintigraphy. The cortical analysis of Tc-99m EC scintigraphy was performed on the summed image obtained from dynamic images using the time interval between the first 45-120 sec.. There was a very close correlation between these two methods with respect to DRF (r = 0.99). In the detection of renal parenchymal lesions, scintigraphy with Tc-99m DMSA detected more lesions, and the sensitivity and specificity of the summed Tc-99m EC images were calculated as 92.6% and 100%, respectively. In addition, the ratios of mean uptake values for Tc-99m DMSA and Tc-99m EC images were 7.59 +/- 2.17 and 2.95 +/- 0.91, respectively. This ratio of Tc-99m EC seems to be acceptable and allows good delineation of the kidneys. But, the main disadvantages of the summed Tc-99m EC images in comparison with static Tc-99m DMSA images are the use of only posterior projection that may be an important drawback in patients with abnormal kidney positions, lower image counts and higher pixel size because of dynamic acquisition.. These results show that summed Tc-99m EC images with an acceptable high image contrast provide an accurate DRF calculation in patients without abnormal kidney positions and allow the detection of most renal parenchymal abnormalities. However, Tc-99m DMSA scintigraphy remains the gold standard method because of its well known advantages.

Topics: Adolescent; Child; Child, Preschool; Cysteine; Female; Humans; Infant; Kidney; Kidney Diseases; Kidney Function Tests; Male; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Technetium Tc 99m Dimercaptosuccinic Acid

Technetium-99m-L,L-ethylenedicysteine (99mTc-L,L-EC), a new renal imaging agent, was introduced as an alternative to 99mTc-mercaptoacetyltriglycine (MAG3). This radiopharmaceutical can be easily labelled at room temperature and has high radiochemical purity and long stability. The aim of this study was to gain clinical experience in using 99mTc-L,L-EC in normal volunteers and patients. The clearance of this radiopharmaceutical was compared with that of iodine-131 ortho-iodohippurate (OIH) in five healthy volunteers. In addition, conventional renogram and whole-body distribution of 99mTc-L,L-EC (40 min and 3 h post-injection) were evaluated in these subjects. Subsequently, ten patients with suspected obstructive nephropathy, four with renovascular disorders and two in acute renal failure were imaged. In five patients with impaired renal function both 99mTc-MAG3 and 99mTc-L,L-EC studies were performed. In each case the scintigraphic images and time/activity curves were evaluated and various semiquantitative parameters calculated and compared. No adverse effects were noted during and after 99mTc-L,L-EC scintigraphy. The mean clearance values for 99mTc-L,L-EC and 131I-OIH in volunteers were 504 and 663 ml/min respectively. The total plasma clearance of 99mTc-L,L-EC was about 75.8% of the 131I-OIH value. In volunteers the parenchymal transit time index, whole kidney transit time index and mean parenchymal transit time for 99mTc-L,L-EC were 63 s, 124 s and 175 s respectively. The mean time to peak activity was 235 s and the time from peak to 50% of peak activity was 402 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Cysteine; Female; Humans; Kidney; Kidney Diseases; Male; Middle Aged; Organotechnetium Compounds; Radionuclide Imaging

Occupational exposure to lead may produce kidney damage, but existing data on the dose range associated with nephrotoxicity are inconclusive. We here assessed renal function under conditions of low to moderate lead exposure using renal scintigraphy.. Fifty-three male foundrymen (exposed group) and fourty male office workers (control group) from a steel plant were included in the study. Glomerular and tubular renal function were assessed by means of (99m)Tc-DTPA and (99m)Tc-EC clearance, respectively. Urinary markers of glomerular dysfunction (albumin) and tubular damage (α1-microglobulin (α1M), β2-microglobulin (β2M), retinol-binding protein (RBP), N-acetyl-β-glucosaminidase (NAG) activity) were determined using latex beads tests or colorimetry. The lead concentration in blood was measured with atomic absorption spectrometry.. The blood lead concentrations were 145.8 (121.3-175.3) and 39.3 (35.1-44.1) µg/l (geometric mean, 95(th) CI, p<0.001) in the exposed and control groups, respectively. Subjects exposed to lead presented with increased (99m)Tc-DTPA clearance (158.3 (148.4-168.8) vs. 135.9 (127.9-144.4) ml/min; p<0.01) and urinary albumin excretion (7.61 (6.28-9.22) vs. 4.78 (4.05-5.65) mg/g creatinine; p<0.001). (99m)Tc-EC clearance and excretion of α1M, β2M, RBP and NAG were not significantly different between the groups. Significant correlations between (99m)Tc-DTPA clearance and blood lead concentrations (r=0.45; p<0.01) and between urinary albumin excretion and blood lead concentrations (r=0.71; p<0.001) were noted.. Use of renal scintigraphy in present study revealed measurable alterations of renal function under the conditions of low-level lead exposure and suggest that increased glomerular filtration may be an early indicator of kidney damage in subjects occupationally exposed to lead.

Topics: Acetylglucosaminidase; Adult; Albuminuria; Alpha-Globulins; beta 2-Microglobulin; Biomarkers; Case-Control Studies; Creatinine; Cysteine; Humans; Kidney; Kidney Diseases; Lead; Male; Metabolic Clearance Rate; Metallurgy; Middle Aged; Occupational Diseases; Occupational Exposure; Organotechnetium Compounds; Poland; Radionuclide Imaging; Radiopharmaceuticals; Retinol-Binding Proteins; Steel; Technetium Tc 99m Pentetate

Several single sample methods for determination of (99m)Tc-mercaptoacetyltriglycine (MAG3) clearance are being used clinically. Kabasakal et al. proposed a similar formula for (99m)Tc-ethylenedicysteine (EC). This study was performed to compare his method with Bubeck et al. formula for (99m)Tc-MAG3 already in use. Twenty-eight subjects divided in two groups were registered which included 22 patients with various renal diseases (group-I) and six normal volunteers (group II). All subjects were studied twice using both the radiopharmaceuticals. The images and renogram parameters, that is TMAX and T1/2 of both the agents, were similar in all the subjects. The clearance of the (99m)Tc-EC was however considerably higher than (99m)Tc-MAG3 in both the groups (mean ± SEM =279 ± 14 ml min(-1)/1.73 m(2) versus 177 ± 15 ml min(-1)/1.73 m(2) in group-I and 377 ± 11.90 ml min(-1)/1.73 m(2) versus 238 ± 8.23 ml min(-1)/1.73 m(2) in group II). This difference was more pronounced in cases with reduced renal functions. Among the Effective Renal Plasma Flow (ERPF) values determined from EC and MAG3 clearances in six normal volunteers, four cases only in MAG3 had ERPF below the lower limit. This study has demonstrated superiority of single sample method for (99 m)Tc-EC clearance over its analogous method for (99m)Tc-MAG3.

Topics: Adolescent; Adult; Aged; Case-Control Studies; Cysteine; Female; Half-Life; Humans; Kidney; Kidney Diseases; Male; Metabolic Clearance Rate; Middle Aged; Organotechnetium Compounds; Predictive Value of Tests; Radioisotope Renography; Radiopharmaceuticals; Renal Plasma Flow, Effective; Severity of Illness Index; Technetium Tc 99m Mertiatide; Young Adult

We evaluated the clinical usefulness of 99Tcm-N,N-ethylenedicysteine (99Tcm-EC), a new renal tubular agent, in normal children and in children with various renal disorders and compared it with 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3). In a first group of children (Group 1), which included 15 patients and 4 normal children, both 99Tcm-EC and 99Tcm-MAG3 renal scintigraphy were performed within a period of 1-5 days. In a second group (Group 2), consisting of 12 patients, only 99Tcm-EC scintigraphy was performed. In the normal children, renograms, differential renal function (DRF) ratios and semi-quantitative parameters of the two agents were similar. For 99Tcm-EC and 99Tcm-MAG3, the mean (+/- S.D.) time to peak activity (Tmax) values were 3.2 +/- 0.5 and 3.1 +/- 0.4 min respectively, and the mean time from peak activity to 50% activity (T1/2) values were 6.3 +/- 0.5 and 6.4 +/- 0.4 min respectively. The mean parenchymal transit time index (PTTI) and mean whole-kidney transit time index (WKTTI) for 99Tcm-EC were 1.7 +/- 0.3 and 2.8 +/- 0.4 respectively, and for 99Tcm-MAG3 they were 1.8 +/- 0.2 and 3.0 +/- 0.3 min respectively. There were also no significant differences between these parameters for the two agents in children with various renal disorders, and the correlation coefficients (r) for DRF, Tmax, T1/2, PTTI and WKTTI were 0.99, 0.98, 0.94, 0.77 and 0.63 respectively. We conclude that 99Tcm-EC has excellent imaging characteristics in children, and even has some advantages over 99Tcm-MAG3. We suggest this agent can be used routinely with children.

Topics: Adolescent; Child; Child, Preschool; Cysteine; Female; Gamma Cameras; Humans; Kidney; Kidney Diseases; Kidney Failure, Chronic; Kidney Function Tests; Male; Organotechnetium Compounds; Reference Values; Regression Analysis; Technetium Tc 99m Mertiatide; Tomography, Emission-Computed

This article evaluates the clinical usefulness of 99mTc-ethylenedicysteine (EC) in patients with various renal disorders. In addition, extraction ratios of 99mTc-EC in five volunteers were also determined.. Twenty patients were intravenously injected with 200 MBq 99mTc-EC and 2.5 MBq [131I]orthoiodohippurate (OIH) simultaneously and 11 blood samples were withdrawn within 60 min. Plasma clearance was determined on the basis of a two-compartment model. Imaging was performed in the posterior projection by acquiring three sets of images. Extraction ratios were determined from the blood samples obtained from the renal vein and abdominal aorta.. Renal clearance of 99mTc-EC was significantly lower than that of OIH (p = 0.0003) with good correlation (r = 0.93). Volume distributions of 99mTc-EC and OIH were 26584 +/- 10807 ml/1.73 m2 and 23148 +/- 7602 ml/1.73 m2, respectively (p = 0.047). The clearance half-lives of 99mTc-EC and OIH were 98 +/- 54 min and 74 +/- 54 min, respectively (p = 0.049). Protein binding of 99mTc-EC (33 +/- 3.2%) was significantly less than that of OIH (62 +/- 2.8%) (p < 0.0001). Red blood cell binding of 99mTc-EC was almost negligible (5.7 +/- 4.3%). Similar extraction ratios were obtained from blood (0.68 +/- 0.08) and plasma (0.70 +/- 0.07) (p = 0.062). The 60-min excretion fractions were similar for 99mTc-EC and OIH, with values of 50% +/- 20% and 51% +/- 19%, respectively (p = 0.9).. Technetium-99m-EC is a suitable radiopharmaceutical for routine renal dynamic studies. Although the biological behavior of 99mTc-EC seems to be different from that of OIH, their clearances demonstrate high correlation. Technetium-99m-EC provides excellent quality images and has high potential in the evaluation of quantitative renal functions.

Topics: Adult; Cysteine; Evaluation Studies as Topic; Female; Humans; Iodine Radioisotopes; Iodohippuric Acid; Kidney Diseases; Male; Organotechnetium Compounds; Radioisotope Renography; Tissue Distribution

Technetium-99m-ethylenedicysteine has recently been developed for renal function studies. The pharmacokinetics of 99mTc-EC were studied by constant infusion technique and compared with 99mTc-MAG3 and 131I-OIH in 11 patients with various renal disorders.. After giving a 7.4 MBq 131I-OIH and 90-110 MBq 99mTc-EC or 99mTc-MAG3 bolus, a constant infusion (1MBq/ml 99mTc-agent and 0.07 MBq/m 131I-OIH was started. Sixteen blood and five urine samples were obtained over three hr.. The renal clearance of 99mTc-EC was higher than that of 99mTc-MAG3. The 99mTc-EC/OIH and 99mTc-MAG3/OIH ratios were 0.75 +/- 0.05 and 0.55 +/- 0.10 (p = 0.00087), respectively. The distribution volume of 99mTc-EC was also higher than that of 99mTc-MAG3 (15722 +/- 4644 and 9509 +/- 2788 ml/1.73m2, respectively; p = 0.072). The 99mTc-EC/OIH and 99mTc-MAG3/OIH distribution volume ratios were 1.03 +/- 0.14 and 0.55 +/- 0.10, respectively (p = 0.0003). The 60-min excretion values of 99mTc-EC and 99mTc-MAG3 were compared to that of OIH. The 99mTc-EC/OIH and 99mTc-MAG3/OIH excretion ratios were 0.96 +/- 0.06 and 1.07 +/- 0.10, respectively (p = 0.162). The protein binding of 99mTc-EC and OIH were found to be 34% +/- 4 and 66% +/- 5, respectively (p < 0.0001). The red cell binding of 99mTc-EC was negligible (3% +/- 1.2) in comparison to OIH (27% +/- 3; p < 0.0001).. This limited study demonstrates the pharmacokinetic and renal clearance properties of 99mTc-EC. This agent has good potential for renal function evaluation.

Topics: Adolescent; Adult; Cysteine; Female; Humans; Iodine Radioisotopes; Iodohippuric Acid; Kidney Diseases; Male; Metabolic Clearance Rate; Middle Aged; Organotechnetium Compounds; Radionuclide Imaging; Technetium Tc 99m Mertiatide

Technetium-99m-labeled N,N-ethylenedicysteine (99mTc-EC) is a new renal imaging agent introduced as an alternative for 99mTc-labeled mercaptoacetyltriglycine (99mTc-MAG3), with similar renal excretion characteristics. To evaluate the diagnostic characteristics of this agent, a gamma camera study was performed.. Sixteen patients with obstructive renal disease and six normal controls were injected with 90 to 110 MBq of 99mTc-EC and 7.4 MBq 131I-labeled orthoiodohippurate (OIH). Serial images were obtained during 20 min for 99mTc-EC and 30 min for OIH. The study was repeated using 90 to 110 MBq 99mTc-MAG3 during the same week.. Renograms, functional ratios and urinary excretion patterns of all three agents were similar. The mean time to peak activity values for OIH, 99mTc-EC and 99mTc-MAG3 were 4.25 +/- 0.37 min, 4.39 +/- 0.32 min and 4.00 +/- 0.24 min, respectively. The time from peak to 50% activity values for OIH, 99mTc-EC and 99mTc-MAG3 were 5.48 +/- 0.80 min, 6.93 +/- 0.69 min and 7.33 +/- 0.85 min, respectively.. It is concluded that 99mTc-EC has excellent imaging characteristics and similar excretion properties to OIH. The advantages of 99mTc-EC over 99mTc-MAG3 are lower hepatobiliary uptake and simplicity of preparation.

Topics: Adult; Cysteine; Female; Humans; Hydronephrosis; Iodine Radioisotopes; Iodohippuric Acid; Kidney Diseases; Male; Middle Aged; Organotechnetium Compounds; Radionuclide Imaging; Technetium Tc 99m Mertiatide; Ureteral Obstruction; Urinary Calculi