99mTc-DMSA Scintigraphy Research Articles

Usefulness of preset count acquisition in pediatric 99m Tc-DMSA planar imaging.

This study was aimed at determining the minimum acquisition count to provide diagnosable image quality (DIQ) and investigating the usefulness of preset count acquisition (PCA) for planar images of pediatric 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy. First, we calculated a coefficient of variation (CV) for DIQ with the shortest acquisition time through visual evaluation in 12 pediatric patients who underwent 99mTc-DMSA scintigraphy. Second, a minimum acquisition count to achieve the CV for DIQ was determined with the single regression analysis using CV as an explanatory variable and the total acquisition count as an objective variable in 81 pediatric patients. Finally, we compared PCA images based on the minimum acquisition count and preset time acquisition (PTA) images for 5min in terms of the acquisition time, CV, and renal uptake ratio in another 23 pediatric patients. The visual evaluation showed that the CV corresponding to DIQ with the shortest acquisition time was 27.1%. The total acquisition count corresponding to DIQ was revealed to be 299,764 in the single regression analysis and was determined to be 300,000 after rounding. The CV and its standard deviation in PCA at 300,000 counts and PTA for 5min were 26.4 ± 0.6% and 24.8 ± 1.3%, respectively. The standard deviation of CV in PCA at 300,000 counts was smaller than that in PTA for 5min, indicating little variation in image quality between cases. The acquisition time in PCA at 300,000 counts (3.1 ± 0.7min) was shorter than that in PTA for 5min (5.0 ± 0.0min). The intraclass correlation coefficient between renal uptake ratios for PCA and PTA was 0.98, indicating an extremely high concordance. The minimum acquisition count required for the DIQ was 300,000. In addition, PCA at 300,000 counts was demonstrated to be useful by providing stable image quality at the shortest acquisition time.

Commentary to “How the 99mTc-DMSA scintigraphy findings are reflected in the adopted treatment of primary vesicoureteral reflux: One centre experience”

Commentary to “How the 99mTc-DMSA scintigraphy findings are reflected in the adopted treatment of primary vesicoureteral reflux: One centre experience”

How the 99mTc-DMSA scintigraphy findings are reflected in the adopted treatment of primary vesicoureteral reflux: One centre experience

Renal changes may have long-term sequalae and prevention is a main goal of management of primary vesicoureteral reflux (VUR). This study aims to reveal how much 99mTc-DMSA scintigraphy findings are reflected in the adopted surgical or non-surgical treatment in children with diagnosed primary VUR and to give the clinicians information regarding their final therapeutic decision. A total 207 children with primary VUR who underwent non-acute 99mTc-DMSA scan were retrospectively evaluated. The presence of renal changes, their grading, differential function asymmetry (<45%) and grade of VUR were compared with subsequent choice of therapy. Altogether 92 (44%) children had asymmetric differential function, 122 (59%) showed presence of renal changes, 79 (38%) had high-grade VUR (IV-V). Patients with renal changes had lower differential function (41%vs.48%) and higher grade of VUR. The incidence of high-grade changes (G3+G4B) afflicting more than one third of the kidney was significantly different between grade I-II, III and IV-V VUR (9%, 27%, 48%, respectively). Renal changes were detected in 76% of surgically and 48% of non-surgically treated patients, high-grade 99mTc-DMSA changes in 69% and 31%, respectively. In children with no scars/dysplasia (G0+G4A), non-surgical treatment prevailed in 77%. The independent predictors for surgical intervention were presence of renal changes and higher grade of VUR, but not functional asymmetry. Over the last 20 years, there has been a shift toward more non-surgical management of VUR. The long-term outcome of this approach should be thoroughly studied. This is the first study analysing renal status in VUR patients using 99mTc-DMSA scan and its grading regarding the adopted treatment. Renal changes in almost half of non-surgically treated children with VUR should be an indicator for earlier diagnosis and effective treatment of acute pyelonephritis and VUR. We recommend distinguishing grade III VUR, as a moderate-grade VUR, because it is linked to higher incidence of high-grade 99mTc-DMSA changes (G3+G4B); our findings of 65% of grade III VURs treated non-surgically should be cautionary. Grade III VUR does not mean a low-risk condition and should alert the clinician to evaluate the extent of renal changes and unmask high-risk cases. Our data strengthens the need to investigate the extent of renal changes in VUR patients regarding treatment decision. Performing 99mTc-DMSA scan individualizes the treatment of VUR patients; its grading can distinguish grade III-VUR as a separate risk entity because it differs significantly in terms of incidence of high-grade renal changes and chosen therapy.

The Spectrum of Parenchymal Changes in Kidneys Affected by Intrarenal Reflux, Diagnosed by Contrast-Enhanced Voiding Urosonography and DMSA Scan.

PurposeTo describe the parenchymal defects in kidneys with intrarenal reflux (IRR) diagnosed using contrast-enhanced voiding urosonography (ceVUS) and 99mTc-DMSA scintigraphy (DMSA scan).Materials and MethodsA group of 186 uretero-renal units (URUs) was analyzed using ceVUS and DMSA scans: 47 without vesicoureteral reflux (VUR) (group A) and 139 with VURs, comprising 73 VURs without (group B), and 66 with IRR (group C). VURs included non-dilating (grades I–II), mildly non-dilating (grade III), and non-dilating (grades IV–V) grades. The parenchymal changes were analyzed using a DMSA scan.ResultsThe median age for VUR diagnosis was 16.5 months in girls, and 8.5 months in boys (Z = 3.9; p = 0.001). IRR occurred in 51.4% of boys and in 25.9% of girls (χ2 = 12.4; p < 0.001). The non-dilating VUR occurred in 44% of boys and 24.1% of girls (χ2 = 7.7; p = 0.005). IRRs characterized upper and lower renal segments (81.8 and 63.6%) and middle segments (33.3%). Both incidence and increase in IRR correlated with the grade of VUR (p < 0.001). The incidence of reduced DMSA signal was statistically different among groups A + B and C, but not between groups A and B (χ2 = 32.2; p < 0.001). No statistically significant relationship existed between the reduced DMSA signal and the grade of VUR in group C. The reduced DMSA signal appeared in 9.9% positions in kidneys from group A, 14% from group B, and 32% from group C. Out of all 118 IRRs, 38.1% had reduced and 61.9% had normal DMSA signal. Among 11 parenchymal scars found in all three groups, 2 belonged to group B, 9 to group C, while group A had no scars.ConclusionThe parenchymal changes are the most prominent in the group with IRR, but they do not significantly differ among kidneys with different grades of VUR. VURs of higher grades are associated with a higher incidence of IRR and early clinical presentation. Scars can also appear in lower-grade VURs accompanied by IRR. Boys with VUR have earlier clinical presentation than girls, as they have significantly higher grades of VUR with a higher proportion of IRRs. Therefore, we suggest a subdivision of VURs into those with IRR and abundant parenchymal damage, and those without IRR and less parenchymal damage.

Comparison of 2D planar and 3D volumetric methods for estimation of split renal function by 99mTc-DMSA scintigraphy

PurposeSplit renal function (SRF) can be measured by using several methods in 99mTc-DMSA scintigraphy. Geometric mean (GM) based methods derived from planar images(2D) have been used for several years, besides; 3D-methods were also reported as an option for assessment of SRF. The purpose of this study to compare 2D and 3D methods for calculation of SRF in pediatric and adult patients. MethodsWe evaluated 212 patients, underwent both planar and SPECT 99mTc-DMSA scintigraphy.2D-SRFs were calculated by GM without background correction (SRFnobcg), GM with background correction in crescent formation from lower lateral borders (SRFcres), and GM with background correction in circumferential formation, including the whole kidney surroundings (SRFcirc). In 3D settings, SRF was measured with SPECT (SRFspect). Paired t-test was used to compare the mean SRFs of each group. Bland-Altman method was used as an agreement method for each method. Analyses were performed based on left kidney SRFs. ResultsIn comparison of 2D and 3D methods, SRFspect was significantly different from SRFnobcg and SRFcres (p=<0.001) but not from SRFcirc (p = 0.155) in all patients. Similar results were found for patients with high creatinine level, SRFcirc and SRFspect were not significantly different (p = 0.317), while significant differences were found between SRFspect and SRFnobcg/SRFcres (p=<0.001).On the other hand, all 2D-methods showed statistical differences (p=<0.001–0.026) from 3D-method in pediatric patients. Bland-Altman-plot demonstrated that SRFcirc underestimated the poor functioning kidneys. ConclusionSRFcirc can be used in measurement of SRF in adult patients with normal functioning kidneys in busy clinics. However, SRFspect provides more accurate results and suggested particularly for pediatric patients and poor functioning kidneys.

Superselective Ischemia in Robotic Partial Nephrectomy Does Not Provide Better Long-term Renal Function than Renal Artery Clamping in a Randomized Controlled Trial (EMERALD): Should We Take the Risk?

BackgroundSuperselective clamping of tumor-targeted arteries aims to eliminate ischemia of the remnant kidney while keeping tumor bed bloodless during excision. ObjectiveTo evaluate the impact of superselective clamping on long-term renal function, compared with renal artery early unclamping. Design, setting, and participantsA randomized monocentric single-blind trial (1:1) was conducted from February 2018 to August 2019. Patients with a single renal tumor were candidates for a robot-assisted partial nephrectomy (RAPN) in a referral center. EMERALD (NCT03679572) was powered to include 50 patients with an interim analysis after 30 cases. InterventionSuperselective RAPN (SS-RAPN) with near-infrared fluorescence (NIRF) or conventional RAPN with renal artery early unclamping. Outcome measurements and statistical analysisThe primary endpoint was the percent change of estimated glomerular filtration rate (eGFR) in the operated kidney after 6 mo (combination of eGFR and relative function on 99mTc-DMSA scintigraphy). Secondary endpoints assessed feasibility and safety of the technique. Results and limitationsRelative eGFR reduction in the operated kidney at 6 mo did not differ significantly (–21.4% vs –23.4%, p=0.66). This absence of difference remained after adjusting on percentage of kidney volume preserved, which was an independent predictor of functional preservation. There were no significant differences in terms of blood loss, change in hemoglobin, postoperative complications, transfusion, and conversion to radical nephrectomy (two vs zero) or to open surgery (one vs zero). Despite a good accrual, the steering committee interrupted the trial after the interim analysis for futility given the absence of trend in favor of SS-RAPN. ConclusionsSS-RAPN using NIRF does not provide better renal function preservation than renal artery clamping, questioning the interest of this technique at a higher risk of bleeding. Patient summaryIn this randomized controlled trial, superselective clamping of tumor feeding arteries did not show any advantage in terms of long-term renal function compared with conventional artery clamping.

Types of Parenchymal Changes Diagnosed on DMSA Scans of Kidneys Affected by Different Grades of Vesicoureteral Reflux.

BackgroundRenal parenchymal damage and scarring usually is associated with urinary tract infection (UTI), whereas the impact of vesicoureteral reflux (VUR) on the kidneys is unclear. We aimed to compare kidneys with all grades of VUR (grades Io-V) and those without VUR by using direct radionuclide cystography, voiding cystourethrography, and findings from 99mTc-DMSA scintigraphy (DMSA scan).Material/MethodsThe present analysis included 253 renal ureteral units (RUU) from 129 children with VUR and recurrent UTI and children with a single febrile UTI associated with abnormal ultrasonographic findings. The 6 grades of VUR (Io, I, II, III, IV, and V) and 35 RUUs without VUR were divided into 4 groups: 1. Non-dilated VUR (grades Io-II); 2. Mildly dilated VUR (grade III); 3. Dilated VUR (grades IV–V); and 4. The control group.ResultsDMSA scanning showed significant differences between the groups with non-dilated VUR, grade III VUR, grades IV–V VUR, and the control group in kidney width (χ2=30.5; P<0.001); position and shape (χ2=30.6; P<0.001); intensity of activity (χ2=38.1; P<0.001); distribution of activity (χ2=34.5; P<0.001); and existence of scars (χ2=16; P<0.001). The probability of abnormalities on DMSA scans increased with the VUR grade. However, inside the groups of dilated and non-dilated VUR we found no significant statistical differences between those characteristics.ConclusionsOur results indicate that kidneys without VUR or with non-dilated lateral VUR and dilated VUR on the contralateral side represent 2 different categories of parenchymal changes.

Interrater Reliability of 99mTc-DMSA Scintigraphy Performed as Planar Scan vs. SPECT/Low Dose CT for Diagnosing Renal Scarring in Children.

99mTc-dimercaptosuccinic acid (DMSA) scintigraphy is currently the method of choice for assessing renal scarring in children, but it is not established whether conducting the scan as a single photon emission tomography combined with low-dose CT (SPECT/ldCT) scan provides additional diagnostic benefits when compared to conventional planar scintigraphy. In the present study, we evaluated the interrater reliability of DMSA SPECT/ldCT vs. planar DMSA scintigraphy for diagnosing renal scarring. Methods: Two nuclear medicine physicians blinded to patient data retrospectively analysed all paediatric 99mTc-DMSA scintigraphes that were conducted in our department for the assessment of post pyelonephritis renal scarring between 2011 and 2016. All scintigraphies included both a planar scan and SPECT/ldCT, and were performed on either a Phillips Precedence 16 slice CT or a Siemens Symbia 16 slice CT. The readers were blinded to each other’s readings and to patient data, and assessed all scans dichotomously for evidence of renal scarring. For each scan, the readers further noted if they were confident in their interpretation. Results: A total of 46 pairs of planar SPECT/ldCT DMSA scans were included. The readers were unconfident about their interpretation of 40% of the planar scans and 5% of the SPECT/ldCT scans. The interrater agreement rate was 72% for planar scans and 91% for SPECT/ldCT, and the corresponding Cohen’s kappa values were 0.38 and 0.79. Conclusion: DMSA SPECT/ldCT is associated with higher reader confidence and interrater reliability than conventional planar DMSA scintigraphy for the assessment of post pyelonephritis renal scarring in children.

Clinical relevance of 18F-FDG PET/CT in the postoperative follow-up of patients with history of medullary thyroid cancer.

BackgroundThe aim of the study was evaluation of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET/CT) in the detection of active disease in the patients with suspected recurrence of the medullary thyroid carcinoma (MTC).Patients and methods18F-FDG PET/CT investigation was performed in 67 patients, investigated from 2010 to 2019. _ Follow up was performed from 6 to 116 months after surgery (median 16.5 months, x± SD = 29±28.9 months). Twenty five of 67 patients underwent 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy, 11 underwent somatostatin receptor scintigraphy (SRS) with 99mTc-HYNIC TOC while 11 123I-metaiodobenzylguanidine (MIBG) scintigraphy.ResultsFrom 67 patients, 35 (52.2%) had true positive 18F-FDG PET/CT findings (TP). Average maximal standardized uptake value (SUVmax) for all TP lesions was 5.01+3.6. In 25 (37.3%) patients findings were true negative (TN). Four (6%) patients had false positive (FP) findings while three (4.5%) were false negative (FN). Thus, sensitivity of the 18F-FDG PET/ CT was 92.11%, specificity 86.21%, positive predictive value 89.74%, negative predictive value 89.29% and accuracy 89.55%. In 27 patients (40%) 18F-FDG PET/CT finding influenced further management of the patient.Conclusions18F-FDG PET/CT has high accuracy in the detection of metastases/recurrences of MTC in patients after thyroidectomy as well as in evaluation and the appropriate choice of the therapy.

Data on biodistribution and dose calculation of 99mTechnetium -Dimercaptosuccinic acid in pediatric patients using a hybrid planar/single emission computed tomography method.

The Biodistribution and absorbed dose data from the administration of radiopharmaceuticals are necessary to analyze the risk-benefit of the procedure. It has particular significance in children, as their metabolism is very different from adults. 99mTc-DMSA scintigraphy is the golden standard imaging technique for the assessment of renal involvement in febrile urinary tract infection and renal sequels. However, 99mTc-DMSA biodistribution data for children are scarce and usually outdated which have been obtained by older methods. In this data article, we analysed the biodistribution of 99mTc-DMSA in 12 pediatric patients using planar/SPECT method. In addition, the radiation absorbed doses were calculated by MIRDOSE software.

Effectiveness of the smoothing filter in pediatric 99mTc-dimercaptosuccinic acid renal scintigraphy.

The present study aimed to evaluate whether the use of a smoothing filter would improve the image quality in pediatric 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy. We retrospectively reviewed 31 kidneys in 16 consecutive pediatric patients aged 10months to 14years. The administered dose was calculated using a weight-based method. Two reviewers randomly evaluated the original planar posterior images and smoothing filter image; they assessed image quality and performed defect evaluations. The evaluation of visual image quality yielded significantly better results for the smoothing filter images than for the original images. Although the smoothing filter images were slightly inferior to the original images in terms of edge sharpness, no significant difference was observed in the defect evaluation. We confirmed that 99mTc-DMSA scintigraphy with a smoothing filter yielded reduced image noise, while maintaining defect evaluation performance and improving image quality.

Evaluation of Renal Function in Obstructed Ureter Model Using 99mTc-DMSA.

Urinary obstruction is a condition of impaired urinary drainage, which may result in progressive renal deterioration. This study applied 99mTc-labeled dimercaptosuccinic acid (99mTc-DMSA) renal scintigraphy to a rabbit model of right ureter obstruction and evaluated its utility in studying obstructive renal diseases. Complete unilateral ureter obstruction in rabbits was generated by complete ligation of the right ureter. Renal function was investigated during a 4-week post-obstruction period by obtaining planar images of 99mTc-DMSA activity following ear vein injection. Renal blood perfusion was evaluated by non-invasive scintigraphy in conjunction with parallel histological and hematological examinations. Renal perfusion was remarkably and rapidly reduced in the ureter-obstructed kidneys. During the experimental period, the size of left kidney appeared normal in the scintigraphic images, but the ureter-obstructed right kidney progressively became larger. Histopathological examination showed flattening and atrophy of tubules, enlargement of interstitial areas, accumulation of extracellular martices and infiltration of inflammatory cells in the obstreucted kidney. 99mTc-DMSA scintigraphy is a sensitive, non-invasive method to assess renal function in unilateral kidney diseases.

Urinary biomarkers of latent inflammation and fibrosis in children with vesicoureteral reflux.

To investigate the urinary levels of TGF-β1, VEGF, and MCP-1 as potential biomarkers of latent inflammation and fibrosis in the kidney before and 6months after correction of vesicoureteral reflux (VUR) in children. A total of 88 patients (mean age 26months) with VUR were divided into three groups: group A-patients with grades II-III VUR, conservative treatment; group B-patients with grades III-V VUR, endoscopic correction of VUR; group C-patients with grades III-V VUR, ureteral reimplantation after failed endoscopic correction. Control group included 20 healthy children. Biomarker levels were measured by ELISA. 99mTc-DMSA scintigraphy and renal histology were performed if possible. At admission, TGF-β1 was close to control in all study groups, VEGF increased with severity of the disease, and MCP-1 increased in group C. Six months after correction of VUR, despite clinical and laboratory improvement, TGF-β1 and MCP-1 increased while VEGF decreased compared to the admission values in all groups; no amelioration of renal scarring was detected either by 99mTc-DMSA scintigraphy or renal histology. The results support our hypothesis that successful correction of VUR is not sufficient to stop or reduce the latent inflammatory and fibrotic processes that have already started in the kidney regardless of the reflux grade and treatment option. Measuring the urinary levels of TGF-β1, VEGF, and MCP-1 may aid in the development of non-invasive, pathophysiologically relevant approach to diagnosis and monitoring of kidney injury and fibrosis in children with VUR.

Planar scan vs. SPECT/low-dose CT for estimating split renal function by 99mTc-DMSA scintigraphy in children.

In the present study, we compared estimates of split renal function (SRF) in paediatric patients of various diagnostic subgroups by 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy using either geometric mean (GM) based on planar scans or a volume of interest (VOI)-based analysis on single photon emission tomography combined with low-dose CT (SPECT/ldCT). Two experienced physicians blinded to patient diagnosis retrospectively analysed all paediatric 99mTc-DMSA scintigraphies that were conducted in our department between 2011 and 2016 and which included both a planar scan and SPECT/ldCT. All scintigraphies were performed on either a Phillips Precedence 16 slice CT or a Siemens Symbia 16 slice CT. SRF was estimated from planar scintigraphy using the geometric mean (GM), while the VOI-based analysis (VBA) was used for kidney segmentation on SPECT/ldCT. RESULTS: A total of 68 scintigraphies were included. A Bland-Altman plot-based analysis showed a bias for SRF of 2.1% with limits of agreement from - 7.5 to + 11.7% for the whole data set but showed larger differences between the two methods outside the normal range of 45-55%. In the GM-based SRF analyses, 29 cases were found to be outside the normal range, and in seven of these, VBA showed normal SRF. In the remaining 39 cases, VBA showed an abnormal SRF in only one case. CONCLUSION: Approximately a quarter of planar DMSA scintigraphies that show an abnormal SRF in paediatric patients may be normal when assessed by SPECT/ldCT, which likely reflects underestimation of the kidney with the poorest function when assessed by GM due to the lack of attenuation correction. Planar scans that show an abnormal SRF in paediatric patients should thus preferably be supplemented by SPECT/ldCT.

The Screening of Renoprotective Agents by 99mTc-DMSA: A Review of Preclinical Studies.

Nephrotoxicity is a prevalent consequence of cancer treatment using radiotherapy and chemotherapy or their combination. There are two methods; histological and biochemical, to assess the kidney damage caused by toxic agents in animal studies. Although these methods are used for the try-out of renoprotective factors, these methods are invasive and time-consuming, and also, lack the necessary sensitivity for primary diagnosis. Quantitative renal 99mTc-DMSA scintigraphy is a noninvasive, precise and sensitive radionuclide technique which is used to assess the extent of kidney damage, so that the extent of injury to the kidney will be indicated by the renal uptake rate of 99mTc-DMSA in the kidney. In addition, this scintigraphy evaluates the effect of the toxic agents by quantifying the alterations in the biodistribution of the radiopharmaceutical. In this review, the recent findings about the renoprotective agents were evaluated and screened with respect to the use of 99mTc-DMSA , which is preclinically and clinically used for animal cases and cancer patients under the treatment by radiotherapy and chemotherapy.

Assessment of individual kidney function in a dog with congenital anomalies of the urinary tract

A 21-month-old entire female labrador retriever was presented for polyuria, pollakiuria, haematuria and intermittent urinary incontinence. Clinical signs were absent during antibiotic treatment but reoccurred shortly after completion of a...

Development of Body Phantom for Evaluation of Appropriate Administered Radioactivities and Image Quality on 99mTc-DMSA Scintigraphy in Pediatric Nuclear Medicine

We conducted a field survey about pediatric nuclear medicine. As a result, it was suggested that 99mTc-DMSA scintigraphy was performed at many institutions, whereas various examinations such as image acquisition and processing are not carried out using the renal phantom. Therefore, we developed the body phantom for the evaluation of appropriate administered radioactivities and image quality with renal scintigraphy in pediatric nuclear medicine. We created three differently sized body phantoms (1-, 5-, and 20-year-old models). These pediatric body phantoms were filled with a 99mTc solution based on the consensus guideline of pediatric radiopharmaceutical administered radioactivity in Japan. The planar image was evaluated using acquisition count, uniformity and defect contrast. SPECT images were evaluated with a recovery coefficient (RC). The acquisition counts for pediatric body phantoms were relatively corresponded to the clinical study. The appropriate acquisition counts and the pixel size for the planar image were approximately 140 counts per pixel and 1.23-1.35 mm at 5 min acquisition times in 1- and 5-year-old pediatric body phantom studies, respectively. Although the uniformity and the cold contrast did not depend on pixel size and body size, the cold contrast was affected by body size. The RC for SPECT images depended on the performance of SPECT systems, the resolution recovery algorithm and body phantom size. The developed pediatric body phantom could allow us to establish optimal image acquisition and more evidence on renal scintigraphy in pediatric nuclear medicine.

Antireflux surgery does not change ongoing renal functional deterioration

Aim Treatment modalities of vesicoureteral reflux (VUR) consist of antimicrobial prophylaxis and antireflux surgery. In this study, we aimed to determine if antireflux surgery changes the course of renal functional deterioration in children with VUR and urinary tract infections (UTI). Methods Medical files of patients with VUR diagnosed during evaluation for UTI were evaluated retrospectively for gender, age, follow-up period, and renal ultrasonography (US) and serial 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy findings. Estimated glomerular filtration rate and urinary protein levels were determined at the initial and last visits, and before the operation in children who had antireflux surgery. The patients were divided into two groups as solely medically treated (Group 1) and both medically and surgically treated (Group 2). Group 2 was further divided as those with stable renal function (Group 2a) and with progressive renal injury (Group 2b). Results There were 140 patients (77 female; mean age 51.6 ± 51.9 months). Group 1 and Group 2 included 82 and 58 patients, respectively. In Group 2, the number of patients with the abnormal US, DMSA scintigraphy, and renal function was higher than in Group 1. Recurrent UTI rate was similar, but progressive scarring was more prominent in the antireflux surgery group. In Group 2, 31 patients had a stable renal function (Group 2a) while 27 had progressive deterioration of renal functions (Group 2b). These subgroups were not different with respect to the rate of high-grade VUR, the presence of a renal scar in DMSA, and UTI recurrence. However, the bilateral renal scar was more common in Group 2b. Conclusion Antireflux surgery does not change the course of ongoing renal injury and renal functional deterioration.

Influência dos métodos de correção de atenuação na quantificação da função renal relativa em cintigrafia renal com 99mTc-DMSA

Introduction – The estimate of relative renal function (RRF) through scintigraphy with dimercaptosuccinic acid labelled with Technetium-99 metastable (99mTc-DMSA) may be influenced by kidney depth (KD), due to attenuation by soft tissue surrounding the kidneys. Considering that rarely this KD is known, several methods for attenuation correction (AC) have been developed, namely those using empirical formulae, such as Raynaud, Taylor or Tonnesen methods, or by direct calculation of the geometric mean (GM). Objectives – To identify the influence of different AC methods on RRF estimateby scintigraphy with 99mTc-DMSA and to evaluate the respective KD variability. Methods : Thirty-one patients were referred for 99mTc-DMSA scintigraphy and underwent the same acquisition protocol. Processing was performed by 2 independent operators, three times per exam, changing for the same processing the methods for the FRR determination: Raynaud’s method, Taylor’s method, Tonnesen´s method, GM and without AC (WAC). Friedman’s test was used to identify the influence of the different AC methods on RRF estimate and Pearson’s correlation test was used to evaluate the association and significance between KD and the variables age, weight and height. Results – Friedman’s test indicated that there were significant differences between methods (p=0.000), except for WAC/Raynaud, Tonnesen/GM and Taylor/GM (p=1.000) comparisons, for both kidneys. Pearson’s test showed a strong positive correlation between weight and the three methods of KD estimation. Conclusions – Taylor’s method, regarding the three methods of KD calculation, is the closest to GM. The choice of the attenuation correction method influences significantly the quantitative parameters of FRR.

Preoperative renal scar as a risk factor of postoperative metabolic acidosis following ileocystoplasty in patients with neurogenic bladder

We investigated relation of preoperative renal scar to incidence of postoperative metabolic acidosis following ileocystoplasty in patients with neurogenic bladder. Thirty patients with neurogenic bladder, who underwent ileocystoplasty, were enrolled in the present study. Median age at ileocystoplasty was 13.9 years and median follow-up period after ileocystoplasty was 8.2 years. Metabolic acidosis was defined based on the outlined criteria: base excess (BE) is less than 0 mmol l(-1). Preoperative examination revealed that no apparent renal insufficiency was identified in blood analysis, although preoperative (99m)Tc-DMSA scintigraphy indicated abnormalities such as renal scar in 14 patients (47%). Incidence of postoperative metabolic acidosis was compared between patients with and without preoperative renal scar, which may reflect some extent of renal tubular damage. Postoperative metabolic acidosis was identified in 13 patients (43%). Incidence of postoperative metabolic acidosis was significantly higher in patients with renal scar (11/14, 79%) compared with patients without renal scar (2/16, 13%; P<0.01). Particularly, all eight patients who had bilateral renal scars showed metabolic acidosis postoperatively. Compared with patients without preoperative renal scar, pH (P<0.05) and BE (P<0.01) were significantly lower postoperatively in patients with preoperative renal scar. However, there was no significant difference in PCO2. Hyperchloremia was observed in each patient with or without preoperative renal scar. Incidence of postoperative metabolic acidosis was significantly implicated in preoperative renal scar. If renal abnormalities are preoperatively identified in imaging tests, we need to care patients carefully regarding metabolic acidosis and subsequent comorbidities following ileocystoplasty.