The 99mTc-DTPA dynamic renal scan with deconvolution analysis.

Dynamic renal studies were performed with 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA). The results were analyzed by the method of mathematical deconvolution in order to obtain the impulse response function of the kidney. Regional analysis of the kidney was attempted by evaluating the independent responses of the renal parenchyma and renal pelvis to a bolus injection of 99mTc-DTPA.     

99mTc-DTPA and 99mTc-DMSA renal gamma imaging in the surveillance of patients with conduit urinary diversion

We studied renal anatomy and function using 99mTc-2-3 dimercaptosuccinic acid (DMSA) and 99mTc-diethylenetriaminepentaacetic acid (DTPA) in 27 patients with conduit urinary diversion. In this condition, free ureteral reflux is often associated with bacteriuria, and these factors are thought to precipitate progressive renal deterioration. Gamma-camera images provided valuable information concerning the structure of the renal parenchyma, the function of individual kidneys and possible ureteral obstruction, thus helping us to decide whether or not to instigate further treatment. The information gained using renal gamma imaging with 99mTc-DTPA and 99mTc-DMSA was complementary and partly overlapping. We preferred the use of 99mTc-DTPA because of its ability to visualise the ureters and the region of ureteroconduit anastomosis. Using diuretic medication, we were able to differentiate true ureteral obstruction from atony in 9 patients using 99mTc-DTPA.     

99mTc-DTPA and 99mTc-DMSA renal gamma imaging in the surveillance of patients with conduit urinary diversion

We studied renal anatomy and function using ^99mTc-2-3 dimercaptosuccinic acid (DMSA) and ^99mTc-diethylenetriaminepentaacetic acid (DTPA) in 27 patients with conduit urinary diversion. In this condition, free ureteral reflux is often associated with bacteriuria, and these factors are thought to precipitate progressive renal deterioration. Gamma-camera images provided valuable information concerning the structure of the renal parenchyma, the function of individual kidneys and possible ureteral obstruction, thus helping us to decide whether or not to instigate further treatment. The information gained using renal gamma imaging with ^99mTc-DTPA and ^99mTc-DMSA was complementary and partly overlapping. We preferred the use of ^99mTc-DTPA because of its ability to visualise the ureters and the region of ureteroconduit anastomosis. Using diuretic medication, we were able to differentiate true ureteral obstruction from atony in 9 patients using ^99mTc-DTPA.     

Quantitation of absolute and relative renal uptake using 99mTc-DMSA: sequential change in time and correlation with 99mTc-DTPA uptake

A renal uptake of 99mTc-DMSA as a function of time and correlation between 99mTc-DMSA and 99mTc-DTPA in renal uptake were discussed. The absolute renal uptake of 99mTc-DMSA calculated by complete correction of tissue attenuation and physical decay showed increase by 5 hours after the administration, except one case with congestive heart failure. The net renal counts attained a maximum between 2 to 3 hours after the administration. There was a good correlation (r -0.992, p less than 0.001) between the relative renal uptake of 99mTc-DMSA (2 hour) and that of 99mTc-DTPA (2-3 min). On the contrary, the absolute renal uptake of 99mTc-DMSA as a indicator of total renal function showed a poor correlation (r = 0.419) to GFR calculated from 99mTc-DTPA. The results indicate that the relative renal uptake of 99mTc-DMSA is a reliable quantitative parameter for split renal function. However, the absolute renal uptake of 99mTc-DMSA may be suggested to be a different renal functioning indicator from GFR calculated from 99mTc-DTPA.     

Physico-chemical study of the radiopharmaceuticals 99mTc-DMSA, 99mTc-EDTA and 99mTc-DTPA interaction with plasmatic proteins

This report studies the binding rate of the radiopharmaceuticals ^99mTc-DTPA, ^99mTc-EDTA and ^99mTc-DMSA to plasmatic proteins.The proteins bind to the tested radiopharmaceuticals in the following sequence: ^99mTc-DTPA < ^99mTc-DMSA(C₁) < ^99mTc-EDTA < ^99mTc-DMSA(C₂) where C₁ and C₂ represent two different Tc-DMSA complexes.The thermodynamic study suggests a quantitative relationship of radiopharmaceutical:protein = 1:1 and an almost nonexistent influence of the temperature, which means that the interacting forces in this process are relatively weak.     

Guidelines for standard and diuretic renogram in children

Special consideration needs to be given to children who undergo dynamic renography. The Paediatric Committee of the European Association of Nuclear Medicine has updated the previous guidelines. Details are provided on how to manage the child, the equipment, and the acquisition and processing protocols. The pitfalls, difficulties and controversies that are encountered are also discussed, as well as the interpretation of the results.     

Validity of99mTc-DMSA renal uptake by planar posterior-view method in children

Renal uptake of 99mTc-DMSA has been quantified by various methods. The aim of this study is to obtain a normal value for 99mTc-DMSA renal uptake calculated by the posterior view method and age variation, and to assess its clinical validity. Scintigrams of 238 children (0-12 years) with 99mTc-DMSA were reviewed. All the children had a clinical history of primary vesicoureteral reflux and/or neurogenic bladder, ureteral or urethral anomalies. Their kidneys were divided into two groups, "normal" and "abnormal" according to their scintigraphic findings and split renal functions. Percent renal uptake per injected dose (% RU) was quantitated from planar images at 2 hours after injection of an age-adjusted dose (26-95 MBq) of 99mTc-DMSA. Calculated total % RU, individual % RU of the right and left kidneys (mean +/- sd) in patients with normal kidneys were 40.7 +/- 5.0%, 20.2 +/- 3.0%, 20.4 +/- 2.7%, respectively. There was no significant correlation between % RU and age (r = 0.231). Longitudinal variation in the % RU in 9 patients ranged from 1.2% to 18%. Our conventional method for quantifyng % RU is simple, practical and feasible in routine clinical practice, especially for children under follow up.     

Reproducibility of renal length measurements with 99mTc-DMSA SPECT.

Renal length measurements are used in evaluating several abnormalities of the pediatric genitourinary tract. This study assesses reproducibility of renal length measurements obtained with 99mTc-dimercaptosuccinic acid (DMSA) SPECT. METHODS: The lengths of 98 kidneys of 51 children (age range, 1-16 y; mean age, 5.4 y) who underwent 99mTc-DMSA SPECT were measured independently by 2 observers. Renal length was calculated by converting pixels between points at the superior and inferior renal margins on a summated coronal image to centimeters. Lengths were measured for kidneys as they appeared in situ and after realignment along their long axes. SPECT reconstruction, choice of display parameters, positioning of points used for measuring, and alignment were performed independently by each observer. Interobserver variability, interobserver correlation, and mean differences between observers' measurements (expressed as measurement of observer 2 - measurement of observer 1) were calculated. RESULTS: Correlation between the observers' measurements was highly significant for both nonaligned and aligned studies (r = 0.95 and 0.97, respectively; both, P < 0.0001). Interobserver variability expressed as 1 SD was 3.6 mm for nonaligned studies and 2.8 mm for aligned studies. The mean difference between the 2 observers' measurements for nonaligned studies was 2.0 +/- 4.8 mm (P < 0.0001) with a range of -11 to 14 mm. For aligned studies the mean difference between the 2 observers' measurements was -0.1 +/- 4.0 mm (P = 0.88) with a range of -20 to 10 mm. Differences between observers were not dependent on absolute renal length (P = 0.68 for nonaligned studies; P = 0.40 for aligned studies). CONCLUSION: The variability in renal length measurements determined by 99mTc-DMSA SPECT is similar to that reported previously using sonography. Because the interobserver differences in renal length are similar to annual renal growth rates during childhood, caution should be applied when incorporating renal length measurements determined by 99mTc-DMSA SPECT into management algorithms. Additional studies are required to further establish interobserver variability, to assess intraobserver variability, and to evaluate means of improving standardization.     

The radionuclide diagnosis of horseshoe kidney

The authors present an interesting case of horseshoe kidney diagnosed by nuclear imaging.     

Low renal uptake of 99mTc-DMSA in patients with proximal tubular dysfunction

In nine patients with different types of proximal tubulopathy and a nearly normal glomerular filtration rate a low uptake of ^99mTc-DMSA in the kidneys was found. The underlying mechanism seems to be an increased urinary excretion of ^99mTc-DMSA. This radiopharmaceutical might be used as a marker of proximal tubular dysfunction.     

Low renal uptake of 99mTc-DMSA in patients with proximal tubular dysfunction

In nine patients with different types of proximal tubulopathy and a nearly normal glomerular filtration rate a low uptake of 99mTc-DMSA in kidneys was found. The underlying mechanism seems to be an increased urinary excretion of 99mTc-DMSA. This radiopharmaceutical might be used as a marker of proximal tubular dysfunction.     

Extrarenal scintigraphic aspects of kidney transplant scans obtained with 99mTc-DTPA

In a retrospective study, 300 scans obtained with 99mTc-DTPA of 100 kidney transplant recipients were studied. The aim was to look for extrarenal scintigraphic aspects encountered specifically in renal transplant scintigraphy and to determine whether some of these phenomena could interfere with adequate interpretation. The most important phenomena seen were radioactivity in the uterus and a cold spot in the pelvis minor caused by a urine filled bladder. If the phenomena that can be encountered are known, the risk of incorrect evaluation is small. In addition, we report on the occurrence of stasis due to disturbed urine flow.     

Extrarenal scientigraphic aspects of kidney transplant scans obtained with99mTc-DTPA

In a retrospective study, 300 scans obtained with^99mTc-DTPA of 100 kidney transplant recipients were studied. The aim was to look for extrarenal scintigraphic aspects encountered specifically in renal transplant scintigraphy and to determine whether some of these phenomena could interfere with adequate interpretation. The most important phenomena seen were radioactivity in the uterus and a cold spot in the pelvis minor caused by a urine filled bladder. If the phenomena that can be encountered are known, the risk of incorrect evaluation is small. In addition, we report on the occurrence of statsis due to disturbed urine flow.     

99mTc-DTPA renal scanning as a confirmatory study in the diagnosis of neonatal adrenal hemorrhage

99mTc-DTPA renal scanning offers a method for demonstrating adrenal hemorrhage as a cause of flank mass in the neonate and for assessing renal function. The hemorrhagic adrenal appears as a tracer-free area over the flattened and displaced kidney. The method is low in radiation and is not hampered by obscuring bowel contents.     

99mTc-DTPA renal scanning as a confirmatory study in the diagnosis of neonatal adrenal hemorrhage

^99mTc-DTPA renal scanning offers a method for demonstrating adrenal hemorrhage as a cause of flank mass in the neonate and for assessing renal function. The hemorrhagic adrenal appears as a tracer-free area over the flattened and displaced kidney. The method is low in radiation and is not hampered by obscuring bowel contents.     

The incidence of left iliac fossa uptake of 99mTc-DTPA in renal scanning

In rare cases, extrarenal uptake of technetium-99m diethylenetriamine penta-acetic acid (^99mTc-DTPA) has been reported, e.g. in tumours or abscesses. Although in our experience a relatively common occurrence, increased uptake in the left iliac fossa (LIF) and its incidence have not been described. This retrospective study set out to establish the incidence of this phenomenon and to exclude malignancy as the cause. All patients who had a renal ^99mTc-DTPA scan between 1 January 1996 and 31 December 1997 had their scans reviewed. Presence and grade of increase in iliac fossa activity were determined by consensus agreement of three observers. The list of patients with increased uptake was cross-referenced against the New South Wales (Australia) Cancer Council database to exclude the possibility of a neoplastic lesion in this region. Increased LIF uptake was noted in 41 of the 231 (18%) consecutive patients (18 men, 23 women; mean age 43 years, range 20-83). Among these 41 patients, uptake was severe in 2 (5%), moderate in 12 (29%) and mild in 27 (66%). No patient had increased uptake in the right iliac fossa. Only one patient had a malignant lesion but this was excluded as being the cause of LIF uptake. No other patient developed malignancy (mean follow-up time 4.1 years; range 3.2-5.1). Increase in LIF uptake is a common, benign finding most likely due to activity within the descending colon. It occurs in approximately 18% of the population, and it is important to recognise such uptake in order to avoid misdiagnoses.