Tc-DMSA Scan Research Articles

99m Tc-DTPA dynamic SPECT/CT renogram in adults: feasibility and diagnostic benefit.

The objective of this study is to investigate the feasibility and potential advantages of 99m Tc-DTPA dynamic single photon emission computed tomography/computed tomography (SPECT/CT) renogram in adults. Fifty-five patients aged 19-80 years (mean 56.3) were enrolled. The imaging protocol included: day 1: 99m Tc-DTPA planar renogram, followed by planar 99m Tc-DMSA scan. Day 3: attenuation-corrected dynamic 99m Tc-DTPA SPECT renogram [DSPECT(AC)] and Cr-51 ethylenediamine tetraacetic acid (EDTA) glomerular filtration rate (GFR) calculation. DSPECT(AC) included an initial CT scan followed by 12 consecutive SPECT sessions acquired via continuous-mode acquisition for a total of 24 min. Fast SPECT sequences (1-2 s/projection, 60 projections, every 6°) were obtained for the first 8 min, followed by slower acquisitions (3-4 s/projection) during the rest of the study. Renal activity was measured in the total kidney volume by regions of interest drawn on consecutive transaxial slices of the third SPECT, which were then copied on the whole 12-SPECT series. Corresponding time-activity curves were created. DSPECT(AC) parameters were compared with those of planar renogram. The reference method for split renal function was 99m Tc-DMSA (geometrical mean of anterior and posterior projection counts) and for GFR the Cr-51 EDTA 2-blood sample clearance method. DSPECT(AC) images were of good quality. There was good correlation between renogram parameters (time to peak activity and NORA20) comparing the two techniques ( r = 0.959 and 0.933, respectively). In 21 cases with >30% absolute difference between the two kidneys, spilt renal function calculation by DSPECT(AC) correlated perfectly ( r = 0.968) with the reference method, whereas planar renogram was less accurate ( r = 0.843). Anatomic information provided by nonenhanced CT offered an integrated structural-functional view valuable for final diagnosis. DSPECT(AC) early kidney uptake as a fraction of injected dose correlated better with reference GFR ( r = 0.789) than the Gates' method ( r = 0.642). 99m Tc-DTPA dynamic SPECT/CT renogram is feasible with conventional SPECT/CT systems. It allows accurate split renal function measurement, offers additional anatomical information and can be used for closer approximation of GFR compared with Gates' method.

소아 <sup>99m</sup>Tc-DMSA 검사에서 신장 섭취율의 평가

The aims of this study were to evaluate the difference of renal uptake rate in 99mTc-DMSA scan on pediatrics by including the bladder. Phantom and Clinical studies were performed. In the phantom study, we put 99m TcO 4 - (300uCi, 11 MBq) in 3cups filled with distilled water at the rate 1:1:0, 1:1:0.5, 1:1:1, 1:1:2 and were placed Lt kidney, Rt kidney and bladder position on the table. To acquire the image, we used Symbia-E gamma camera from Siemens with preset count method(400,000 counts). In quantitative analysis, the counts of drawing ROIs on the phantom were analyzed. In clinical studies, we analyzed the 20 pediatrics who were examined by 99m Tc-DMSA scan. At first, the images were acquired with both kidney and bladder. Secondly we acquired images after shielding the bladder. And the data were compared using a pared t-test by SPSS(ver.22.0). As a result of renal phantom’s experiment, we compared with average of uptake rate(%), 1:1:0 was Lt 43.32%, Rt 45.97%, 1:1:0.5 was Lt 35.79%, Rt 36.89%, 1:1:1 was Lt 29.68%, Rt 31.45% and 1:1:2 was Lt 22.89%, Rt 24.32%. There was no correlation between the zoom and uptake rate. The results of patient were that excluded bladder was 29.83±8.81%(Lt), 24.29±6.66%(Rt) and included bladder was 26.65±8.03%(Lt, 21.78±6.24%(Rt). This is deemed statistically significant (p<0.05). Renal uptake rate was undervalued because the counts of bladder were included in the total counts. Keyword : 99m Tc-DMSA scan, ,renal uptake rate

Acute 99mTc DMSA Scan Predicts Dilating Vesicoureteral Reflux in Young Children With a First Febrile Urinary Tract Infection

This study aimed to examine the ability of acute (99m)Tc DMSA scan for predicting dilating (grades III-V) vesicoureteral reflux (VUR) after a first febrile urinary tract infection in children aged 2 years or younger. All children underwent ultrasonography (US), (99m)Tc DMSA scan, and voiding cystourethrography. Sensitivity, specificity, positive and negative predictive values, likelihood ratios, and receiver operating characteristic curves were performed to assess the diagnostic accuracy for predicting dilating VUR. Follow-up scan was performed at least 6 months after the acute infection to evaluate the presence of renal scarring (RS) or new scars. Of the 473 children analyzed (289 boys and 184 girls; median age, 5 months), 282 (59.6%) had abnormal acute (99m)Tc DMSA scan findings. There was VUR in 153 children (32.3%), whereas 95 (20.1%) had dilating VUR. The sensitivity and negative predictive value in predicting dilating VUR were 95.8% and 97.9%, respectively, for (99m)Tc DMSA and 97.9% and 98.6%, respectively, for combined US and (99m)Tc DMSA, whereas the positive and negative likelihood ratios were 1.90 and 0.08, respectively, for (99m)Tc DMSA and 1.57 and 0.06, respectively, for combined studies. On multivariate analysis, dilating VUR was a predictor for developing RS and new scars. Our results reveal the usefulness of acute (99m)Tc DMSA scan for predicting dilating VUR in children with a first febrile urinary tract infection. A voiding cystourethrography is indicated in only children with abnormalities found on a (99m)Tc DMSA and/or a US. The presence of dilating VUR predisposes to developing RS and new scars.

Crossed renal ectopia: can it be a diagnostic problem?

Crossed renal ectopia (C-RE) is a rare congenital anomaly in which both kidneys are located unilaterally. The crossed kidney is situated on the side opposite to its ureteral orifice and usually lies below the normal kidney. The frequency of this malformation is estimated at 0.05% to 0.1%. Most of the patients remain asymptomatic. In other cases C-RE is diagnosed incidentally on routine ultrasonography, due to the presence of unspecific symptoms. The diagnosis of C-RE is possible due to a wide range of imaging techniques: US, IVU, CT, MRI, and TcDMSA scan. Among them IVU, CT, and MRI have the highest degree of confidence. The aim of this retrospective study was to present our own experience with 5 children affected with C-RE, emphasizing the differences in clinical picture and low sensitivity of ultrasound images. In all of them the final diagnosis was established by IVU or MRI.

Prevention of chronic kidney disease in spina bifida

The prevalence of progressive chronic kidney disease (CKD) in children and adults with spina bifida is considerable, rising, and entirely preventable. PREVENTION OF SPINA BIFIDA: The best prevention of CKD in spina bifida is prevention of spina bifida itself through strategies that include folate supplementation, ideally before pregnancy. Dysfunctional bladder outlet causes febrile Urinary Tract Infections (UTI), even with clean intermittent catheterization (CIC), and subsequent renal scarring. The development of secondary vesicoureteric reflux (VUR) increases the risk of renal scarring and CKD. Creatinine-based methods are insensitive because of low muscle mass and underdeveloped musculature in the legs. Only Cystatin C-based eGFR can reliably assess global renal function in these patients. However, unilateral renal damage requires nuclear medicine scans, such as (99m)Tc DMSA. (VIDEO)URODYNAMICS STUDIES (UDS): Early treatment is recommended based on UDS with anticholinergics, CIC, and antibiotic prophylaxis when indicated. Overnight catheter drainage, Botox, and eventually augmentation cystoplasty are required for poorly compliant bladders. A continent child or one rendered continent following surgery is at a higher risk of renal damage. A multidisciplinary approach is required to reduce the burden of CKD in patients with spina bifida. The right tools have to be utilized to monitor these patients, particularly if recurrent UTIs occur. Cystatin C eGFR is preferred for monitoring renal damage in these patients, and (99m)Tc DMSA scans have to be used to detect unilateral renal scarring.

Effect of Percutaneous Nephrolithotomy and Tract Dilatation Methods on Renal Function: Assessment by Quantitative Single-Photon Emission Computed Tomography of Technetium-99m–Dimercaptosuccinic Acid Uptake by the Kidneys

The aim of this study was to determine the impact of percutaneous nephrolithotomy (PCNL) and tract dilatation methods on global and regional renal function using quantitative single-photon emission computed tomography (QSPECT) of technetium-99m-dimercaptosuccinic acid ((99m)Tc-DMSA). Seventy-five patients undergoing PCNL between May 2008 and April 2009 were included in this randomized study. Of the 75 patients, 50 were evaluated by QSPECT of (99m)Tc-DMSA examinations before and at 3 to 6 months after surgery. This group of patients were categorized into three groups according to the dilatation technique used: group I (balloon dilator, n = 12 [24%] patients), group II (metal dilator, n = 14 [28%] patients), and group III (Amplatz dilator, n = 24 [48%] patients). Of 50 renal units, new focal cortical defects on (99m)Tc-DMSA scan were seen in nine patients (18%). In six of these kidneys the site of focal defect corresponded to the access site for tract formation during PCNL (two in group II and four in group III). Total relative uptake and total area of treated kidney, for the entire group, increased from 42.2% and 42.3% preoperatively to 44.12% and 43.9% postoperatively. There was no statistically significant differences between the groups for total uptake and area of the treated kidneys before and after the procedure (p > 0.05 for each parameter). QSPECT of (99m)Tc-DMSA confirms that renal function is preserved or often improved after percutaneous stone removal, and nephrostomy tract dilatation methods have similar effects on renal function.

Decrease of Renal Function due to Warm Ischemia after Laparoscopic Partial Nephrectomy: Evaluation Using 99mTc-DMSA Renal Scintigraphy

Introduction: The purpose of this study is, using technetium-99m-dimercaptosuccinic acid (^99mTc-DMSA), to evaluate the decrease of renal function caused by warm ischemia. Patients and Methods: The ^99mTc-DMSA scan was performed before and 1, 3 and 6 months after the operation for 19 consecutive patients. The patients were divided into three groups by warm ischemic time (group A: ≤40 min, B: >40 min ∩ ≤60 min, C: >60 min). Renal function of the unresected part was defined as the uptake to unresected part relative to the uptake to the contralateral kidney. The reduction of renal function was expressed as a ratio of the function after the surgery divided by function before the surgery and was compared between the three groups. Results: The reduction in group C after 1 and 3 months tended to be greater than that in group A or B, although not reaching statistical significance (one-way ANOVA test, 1 month: p = 0.15 and 3 months: p = 0.13). There was a significant difference in reduction of renal function between the three groups after 6 months (one-way ANOVA test, p = 0.02). The Scheffé test showed a statistical significance between groups A and C (p < 0.05). Conclusion: Renal function calculated by ^99mTc-DMSA shows that prolonged ischemic time causes significant damage to the kidney.

Inter- and Intraobserver Variability of 99mTc-DMSA Renal Scintigraphy: Impact of Oblique Views

(99m)Tc-Dimercaptosuccinic acid (DMSA) scintigraphy is a frequently used diagnostic test to assess the presence and severity of cortical damage. The aim of this study is to investigate the variability in the interpretation of (99m)Tc-DMSA scans, evaluate the usefulness of oblique images, and assess their impact on scan interpretation. Two experienced nuclear medicine physicians independently interpreted 100 (99m)Tc-DMSA scans (197 kidneys) 4 times. Interpretation was twice based on posterior projection images and twice based on posterior and posterior oblique projection images. For each kidney, the observers had to choose between the following results: normal, abnormal, and indeterminate. The indices of variability used were the percentage of agreement, kappa-statistic, and marginal homogeneity. Intraobserver and interobserver reproducibility (kappa-values) varied between 0.683 and 0.708 and between 0.609 and 0.671, respectively, for posterior images. Disagreement in (99m)Tc-DMSA scan interpretation occurred in 18% of kidneys within observers and in 21% of kidneys between observers when only posterior images were used. Oblique views changed the interpretation in 14% and 11.5% of kidneys for the first and second observers, respectively. The use of oblique views increased the agreement rate within and between observers (kappa-values, 0.725-0.812 and 0.768-0.732, respectively; mean agreement, 86.5 and 87.25, respectively). Oblique views were found useful in approximately 13% of kidneys and affected inter- and intraobserver variability. Our results suggest that oblique views should be used routinely in children with clinically suspected urinary tract infection to reliably interpret images.

Sectorial Technetium-99m-Dimercaptosuccinic Acid Scintigraphy for Monitoring the Effect of Extracorporeal Piezoelectric Lithotripsy for Calyceal Calculi on Regional Renal Function

Objective: To apply a semiquantitative method for analysis of technetium-99m-dimercaptosuccinic acid (^99mTc-DMSA) renal scintigraphy for monitoring the effect of extracorporeal piezoelectric lithotripsy (EPL) in patients with calyceal stones on regional kidney function and to check whether EPL had caused any deleterious effect on the target calyceal renal parenchymal function. Patients and Methods: Forty patients (mean age 35 years) suffering from calyceal stones documented by abdominal plain radiography, intravenous urogram or abdominal ultrasound were studied. All patients were treated by EPL. ^99mTc-DMSA scan was performed before and 4 weeks after EPL. Sector analysis involved calculation of the relative function of the target calyx to the function of the ipsilateral kidney and the relative function of the treated kidney to global renal function. Results: The stone sizes were 6–11 mm in diameter and 11 were located in the upper, 13 in the middle and 16 in the lower calyx. After EPL, the overall stone clearance rate was 85% (100% for calculi in the upper and middle calyces, 62% for lower calyces). The sector analysis did not show statistically significant change of the relative regional (calyceal) or whole kidney function between the pre- and post-EPL ^99mTc-DMSA scans. Using sector analysis, EPL appeared to be a safe modality and its usage was not associated with any untoward effect on calyceal or whole kidney function. Conclusion: Sector analysis of ^99mTc-DMSA renal scan is a simple semiquantitative method for monitoring regional changes of kidney function after EPL for treatment of calyceal stone.