Protective Effects of Omega-3 Fatty Acids Supplementation Against Renal Parenchymal Scarring in Children with Acute Pyelonephritis: Results of a Pilot Clinical Trial

AIM

This trial aimed to determine if supplementation with omega-3 fatty acids as an adjunct therapy to antibiotic treatment can have protective effects against renal scar formation after acute pyelonephritis (APN) in pediatric patients.

BACKGROUND

Current evidence points out that besides antibiotic treatment, early administration of antioxidant and anti-inflammatory compounds may be effective in reducing the occurrence of renal damage following APN in children.

OBJECTIVE

The main endpoint of the trial was the comparison of the development of renal scarring formation after APN in an omega-3 fatty acids-treated group and in a control-treated group.

METHODS

This prospective randomized, controlled trial study was conducted from March 2016 to May 2018 on 60 children with a diagnosis APN in a tertiary hospital in Iran. After the diagnosis of APN based on the clinical signs and symptoms, urine analysis, urine culture, and dimercaptosuccinic acid renal scan (DMSA scan), the patients were randomly allocated into either the control group (n=30 patients: received standard antibiotic treatment only) or the intervention group (n=30 patients: received standard antibiotic-treatment in combination with oral omega-3 fatty acids based on the children's weight for three consecutive days). A second DMSA scan was performed for the patients at a minimum of six months after treatment. The development of renal scars was evaluated by comparing the baseline DMSA scan lesions with the follow-up DMSA scan lesions.

RESULTS

Fifty patients, including 26 and 24 individuals in the control and intervention groups, respectively, completed the entire course of the study. Renal parenchymal involvement based on the baseline DMSA scan was similar in the two groups (p-value =0.85, 0.90, and 0.53 regarding the right, left, and both kidney units together, respectively). Although comparison of the follow-up DMSA scan lesions to the baseline DMSA scan lesions considering the right and left kidneys as separate units between two groups did not reach the significant level, when considering both left and right kidney units together, results showed a statistically significant difference between groups in favor of the intervention group (p-value =0.04).

CONCLUSION

Although preliminary, the results of this study showed that administration of omega-3 fatty acids, a natural supplement with well-known anti-inflammatory and antioxidant properties, as an adjunct therapy to standard antibiotic treatment might significantly reduce the incidence of the occurrence renal scarring following APN in children. Confirmation of these results requires further studies.

Renal Cortical Scarring: 68Ga-PSMA-11 PET versus 99mTc-DMSA Scan in a Case with Pyelonephritis

We previously reported ⁶⁸Ga-prostate‑specific membrane antigen (PSMA)-11 and ^99mTcdimercaptosuccinic acid (DMSA) images of the 1st case of our prospective research comparing renal PSMA PET to DMSA scan in adult patients with pyelonephritis. Here, we present renal cortical PSMA PET and DMSA images of our 2nd patient with chronic recurring pyelonephritis which demonstrated renal parenchymal defects secondary to scarring in the kidney.

Renal Cortical 68Ga-PSMA-11 PET and 99mTc-DMSA Images

⁶⁸Ga-prostate-specific membrane antigen (PSMA) ligands are novel PET radiotracers for prostate cancer. These radiotracers also localize in the normal renal cortex to a high degree and can demonstrate parenchymal defects. We recently started a prospective research study to compare ⁶⁸Ga-PSMA-11 PET/CT with ^99mTc-dimercaptosuccinic acid (DMSA) scan in adults with pyelonephritis. Here, we present a side-by-side comparison of renal cortical PSMA PET/CT and DMSA images of an adult patient with chronic recurring pyelonephritis. Methods: Our prospective study was approved by the Ethical Committees. DMSA images (multiple planar and SPECT) were obtained 3 h after intravenous injection of 111 MBq (3 mCi) of ^99mTc-DMSA. On a separate day, we obtained PET/CT images of the kidneys 60 min after intravenous injection of 74 MBq (2 mCi) of ⁶⁸Ga-PSMA-11 after the patient provided written informed consent. Results: The patient was a 46-y-old woman with history of chronic recurring pyelonephritis. Both DMSA scan and PSMA PET/CT demonstrated slight cortical thinning with mildly reduced uptake in the upper pole of the right kidney, with no significant cortical defects. There was an excellent distribution of activity in the renal cortex and better image resolution with PSMA PET than with DMSA scan. Non-attenuation-corrected PSMA PET images also showed the same findings, with reasonable image quality. Conclusion: In our first case, ⁶⁸Ga-PSMA-11 PET imaging provided promising results in an adult patient with pyelonephritis. The results of our prospective study on a larger number of adult patients will provide a more accurate comparison of ⁶⁸Ga-PSMA-11 PET to ^99mTc-DMSA scanning in pyelonephritis.

Prediction of vesicoureteral reflux in children with febrile urinary tract infection using relative uptake and cortical defect in DMSA scan

BACKGROUND

Vesicoureteral reflux (VUR) is an important urologic anomaly that causes renal injury in children with febrile urinary tract infection (UTI). The present study aimed to evaluate the associations of abnormalities detected on technetium-99m-labeled dimercaptosuccinic acid (DMSA) scans, focusing on the association with VUR of the levels of relative decrease in kidney function and cortical defects after a first febrile UTI in children.

METHODS

All 171 children underwent ultrasonography, DMSA scan and voiding cystourethrography (VCUG). The features of ultrasound and DMSA scans were compared between patients with (n = 48) and without VUR (n = 123). The relative uptake (RU) by each kidney was derived from the absolute value of the differences between the value for RU of radionuclide in the right kidney and that in the left kidney. The extent of cortical defects (ECD) was graded according to the number of compartments that contained cortical defect in both kidneys (right upper/right lower, left upper/left lower). Receiver operating characteristic curves were constructed to examine the diagnostic value of these parameters of ultrasound and DMSA scans for predicting VUR.

RESULTS

The ratio of patients having hydronephrosis on ultrasound or cortical defects on DMSA scan did not differ significantly between VUR and non-VUR groups. However, the absolute values of the RU and the scores for ECD were significantly higher in the VUR group than in the non-VUR group. The area under the curves for these two parameters were higher than those for the presence of hydronephrosis or the presence of cortical defects or both.

CONCLUSION

Decreased relative function and increased extents of cortical defects on DMSA scan may be associated with the presence of VUR. These findings may assist pediatricians to decide whether febrile UTI children need to undergo VCUG.

Interobserver variability for interpretation of DMSA scans in the RIVUR trial

INTRODUCTION

Technetium-99m dimercaptosuccinic acid (DMSA) renal scans are used in the diagnosis of renal scarring. In the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial that randomized 607 children, DMSA renal scans were used for evaluating the presence and the severity of renal scarring.

OBJECTIVE

The aim was to determine interobserver variability in reporting of DMSA renal scans in the RIVUR trial.

STUDY DESIGN

We compared DMSA renal scan reports for renal scarring and acute pyelonephritis from all non-reference local radiologists (ALRs) at study sites with adjudicated as well as non-adjudicated reports from two reference radiologists (RRs) of the RIVUR trial. Two-way comparisons of concordant and discrepant responses were analyzed using an unweighted kappa statistic between the ALR and the adjudicated RR interpretations. All analyses were performed using SAS v 9.4 (SAS institute 2015) and significance was determined at the 0.05 level.

RESULTS

Of the 2872 kidneys evaluated, adjudicated RR reports had 119 (4%) kidneys with renal scarring compared with 212 (7%) by the ALRs. For 79% kidneys the grading for scarring reported by ALRs was either upgraded (24%) or downgraded (55%) by RRs. For acute pyelonephritis (n = 2924), adjudicated RR reports had 85 (3%) kidneys with pyelonephritis compared with 151 (5%) by the ALRs. For 85% kidneys, the grading for pyelonephritis reported by the ALRs was either upgraded (28%) or downgraded (57%) by the RRs. A three-way comparison revealed that all three (RR1, RR2, and ALR) agreed over presence of renal scarring in 19% cases and two of the three agreed in 80% cases. The respective numbers for pyelonephritis were 13% and 84%. The agreement rate for all DMSA scan reports between the RRs and the ALRs was 93%.

DISCUSSION

The study revealed significant interobserver variability in the reporting of abnormal DMSA renal scans compared with the previously published studies. A noteworthy limitation was a lack of uniformity in local reporting of the scans.

CONCLUSIONS

Our study highlights the need for optimizing the clinical yield of DMSA renal scans by more specific guidelines, particularly for standardized and uniform interpretation.

Usefulness of 99mTc-dimercaptosuccinic acid renal scan in the diagnosis and follow-up of acute tubulointerstitial nephritis in children

BACKGROUND

Symptoms and signs of acute tubulointerstitial nephritis (ATIN) are nonspecific; therefore, renal biopsy is often necessary to clarify the diagnosis. The aim of this study was to evaluate the use of ^99mTc-dimercaptosuccinic acid (DMSA) scintigraphy in the diagnosis and follow-up of ATIN.

METHODS

We retrospectively reviewed the charts of five patients (nine renal units) with a median age of 14 years who underwent DMSA scan after a clinical and/or biopsy-proven diagnosis of ATIN. The exam was performed within 1 month after disease onset and repeated at a median time of 12 months after the acute phase.

RESULTS

DMSA renal scans performed during the acute phase allowed the discovery of suggestive findings, including diffuse reduction of the renal uptake of radionuclide and presence of multiple 'cold' focal lesions in a corticomedullary distribution. The follow-up scintigraphy resulted normal in two patients who were treated with steroids and in one patient who presented a mild renal dysfunction in the acute phase. By contrast, the control scan showed persistent renal damage in one patient who was further readmitted because of hypertension and in one renal transplanted patient who presented a Stage 3 acute kidney injury in the acute phase.

CONCLUSIONS

DMSA renal scan might be a reliable tool for an early non-invasive diagnosis of ATIN in children and might be particularly useful in those patients who are not candidates for a kidney biopsy. Moreover, DMSA scan gives accurate follow-up evaluation, as it allows monitoring of the evolution of acute renal parenchymal inflammation with potential risk of renal scar formation. Due to the small sample size, our findings warrant further validation in a larger study.

Computing quantitative indicators of structural renal damage in pediatric DMSA scans

OBJECTIVES

The proposal and implementation of a computational framework for the quantification of structural renal damage from ^99mTc-dimercaptosuccinic acid (DMSA) scans. The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner.

MATERIALS AND METHODS

From a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan.

RESULTS

A fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%).

CONCLUSIONS

The proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

Urinary tract infection pattern in adult women followed from childhood

BACKGROUND

The aim of this study was to describe the pattern of urinary tract infection (UTI) and bladder function in women who had experienced recurrent UTI in childhood, with and without consequent renal damage, and followed for three to four decades.

METHODS

A population-based cohort of women who had been followed from the first UTI in childhood and previously studied at a median age of 27 years was studied at a median age of 41 years. Renal damage was evaluated by (99m)Tc-dimercaptosuccinic acid scan. Clinical data were collected on the pattern of recurrent UTIs and bladder function.

RESULTS

A total of 86 women were investigated, of whom 58 had suffered renal damage and 28 were without. Febrile UTI in adulthood had occurred in 22 patients, once in 15 women and twice or more in seven women. There was a change in the infection pattern over time, evident already in childhood, that was characterized by a decrease in UTI frequency and a shift from febrile to non-febrile infections. A significant association was found between renal damage and febrile UTI (p = 0.046), and between abnormal bladder function and recurrent non-febrile UTI (p = 0.002). There was no relationship between persisting vesicoureteral reflux (VUR) and proneness to either symptomatic UTI (p = 0.99) or febrile UTI in adulthood (p = 0.14).

CONCLUSIONS

Among this study cohort there was a continuously decreasing rate of febrile UTI in adulthood. Persisting VUR was not related to UTI in adulthood. Abnormal bladder function was related to non-febrile UTI but not to febrile UTI.

Renal Abnormalities Among Egyptian Children With Hemophilia A Using Renal Scintigraphy: Relation to Risk Factors and Disease Severity

Many risk factors may contribute to renal disease in patients with hemophilia A.

AIM

We aimed to evaluate functional and structural renal abnormalities among a group of Egyptian children with severe and moderate hemophilia A using technetium-99m diethylene triamine pentaacetic acid (^99mTc-DTPA) and technetium-99 m dimercaptusuccinic acid (^99mTc-DMSA) scan. We also aimed to determine the relation between these abnormalities and different risk factors and disease severity.

PATIENTS AND METHODS

Forty male patients, 16 with severe and 24 with moderate hemophilia A, were enrolled in this study. Their mean age was 10.2 ± 4.3 years (range, 5-17 years). Full history taking, clinical examination, laboratory, and radionuclide investigations including serum creatinine, blood urea nitrogen (BUN), urine analysis, creatinine clearance, 24-hour urinary protein, ^99mTc-DTPA scan, and ^99mTc-DMSA scan were performed to all enrolled patients.

RESULTS

Serum creatinine and BUN were normal in all patients, and corrected creatinine clearance was diminished in 2 patients. However, ^99mTc-DTPA results yielded 19 (47.5%) patients with diminished glomerular filtration rate (GFR). Moreover, it showed that 14 (35%) had obstructive uropathy, 15 (37.5%) had obstructive nephropathy, while 11 (27.5%) patients showed normal scan. One patient had atrophy of 1 kidney on ^99mTc-DMSA scan. Among our cohort, 5 (12.5%) patients were hypertensive. Microscopic hematuria was detected in 14 (35%) patients while 72.5% had proteinuria. We found an association between hematuria and hypertension with diminished GFR.

CONCLUSION

Despite normal kidney functions (serum creatinine and BUN), we found a high rate of diminished GFR and obstructive uropathy and nephropathy as detected by ^99mTc-DTPA scan among children with hemophilia A.

Radiologic and clinical evaluation of children with first febrile urinary tract infection

Background and objectives

Accurate diagnosis of acute pyelonephritis (APN) is clinically challenging in young children. The evaluation methods for APN and its major risk factor, vesicoureteral reflux (VUR), have been revised in recent years. The aim of this study was to evaluate the value of different radiologic investigations in children experiencing the first episode of APN.

Materials and methods

This study included 425 children of 2–12 months of age (17.5% male, 82.5% female) with APN. APN was defined as a positive urine culture associated with focal or diffuse decreased cortical uptake and preservation of renal contour indicated by DMSA renal scan.

Results

The mean age at diagnosis was 39.2 ± 1.56 months. The following signs were observed in the patients: fever ≥ 38.5 °C, 66.8%; positive CRP, 85.4%; ESR > 25, 78.6%; and leukocytosis > 13,000/mm³, 53.4%.

Pyelocalyceal fullness and increased parenchymal echogenicity were the most common renal ultrasonography findings, and ultrasonography had 34% sensitivity and 53% specificity for these two findings. DMSA scan and ultrasound findings of APN were not significantly correlated (P = .112).

VUR was found in 42.2% of patients. DMSA scanning was not reliable for the diagnosis of VUR (P = .956), with 42% sensitivity and specificity.

VUR was identified in 42.7% of patients by ultrasound (P = .001), and the diagnostic rate was related to the VUR severity. Ultrasound had 42.7% sensitivity and 27% specificity for the diagnosis of VUR.

Conclusion

Determination of inflammatory markers is recommenced for the evaluation of children with APN. In addition, normal ultrasound is a valuable imaging tool for excluding high grade VUR.

Comparison of magnetic resonance urography to dimercaptosuccinic acid scan for the identification of renal parenchyma defects in children with vesicoureteral reflux

OBJECTIVE

The objective of this study was to compare the accuracy of dimercaptosuccinic acid (DMSA) renal scan to magnetic resonance urography (MRU) in the identification of renal parenchyma defects (RPD).

MATERIALS AND METHODS

Twenty-five children with history of acute pyelonephritis and vesicoureteral reflux underwent DMSA scan and MRU to determine the presence of RPD. DMSA scans and MRUs were each evaluated by two radiologists and agreement achieved by consensus. Discordant DMSA-MRU findings were re-evaluated in a side-by-side comparison and an ultimate consensus reached.

RESULTS

The ultimate consensus diagnosis was 18 kidneys with RPDs in 15 patients, of which five were classified as mild RPDs, six as moderate RPDs, and seven as severe RPDs. Although DMSA scan and MRU were similar in their ability to diagnose RPDs, MRU was considered to represent the true diagnosis in 11 of the 12 discordant cases in consensus review by four pediatric radiologists. MRU showed a much higher inter-observer agreement with a weighted kappa of 0.96 for both kidneys compared to 0.71 for the right kidney and 0.86 for the left kidney by DMSA scan.

CONCLUSIONS

Our results suggest that MRU is superior to DMSA scan in the identification of renal parenchyma defects.