Renal cortical scintigraphy in the diagnosis of acute pyelonephritis

Role of Functional SPECT and PET in Renal Emergencies

Renal scintigraphy is a centerpiece of nuclear medicine and is also commonly applied for (peri-)acute care. In this regard, referrals by the treating physician include: I.) acute obstructions caused by gradual and infiltrative tumor growth or renal off-target effects under anti-tumor treatment, II.) functional issues in infants, for example, structural abnormalities such as duplex kidneys or uroliths in adults, which can also trigger III.) Infections of renal parenchyma. Renal radionuclide imaging is also requested due to IV.) acute trauma to the abdomen, for example, to assess renal scarring or upon further follow-up after reconstructive surgery. We will discuss clinical applications of (peri-)acute renal scintigraphy, along with future prospects on the use of more advanced nuclear imaging techniques such as renal positron emission tomography.

Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

BACKGROUND

In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized. This is an update of a review first published in 2015.

OBJECTIVES

The objectives of this review were to 1) determine whether procalcitonin (PCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) can replace the acute DMSA scan in the diagnostic evaluation of children with UTI; 2) assess the influence of patient and study characteristics on the diagnostic accuracy of these tests, and 3) compare the performance of the three tests to each other.

SEARCH METHODS

We searched MEDLINE, EMBASE, DARE, Web of Science, and BIOSIS Previews through to 17th December 2019 for this review. The reference lists of all included articles and relevant systematic reviews were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We only considered published studies that evaluated the results of an index test (PCT, CRP, ESR) against the results of an acute-phase ⁹⁹Tc-dimercaptosuccinic acid (DMSA) scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of UTI. The following cut-off values were used for the primary analysis: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/hour for ESR.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate pooled random-effects pooled sensitivity and specificity values.

MAIN RESULTS

A total of 36 studies met our inclusion criteria. Twenty-five studies provided data for the primary analysis: 12 studies (1000 children) included data on PCT, 16 studies (1895 children) included data on CRP, and eight studies (1910 children) included data on ESR (some studies had data on more than one test). The summary sensitivity estimates (95% CI) for the PCT, CRP, ESR tests at the aforementioned cut-offs were 0.81 (0.67 to 0.90), 0.93 (0.86 to 0.96), and 0.83 (0.71 to 0.91), respectively. The summary specificity values for PCT, CRP, and ESR tests at these cut-offs were 0.76 (0.66 to 0.84), 0.37 (0.24 to 0.53), and 0.57 (0.41 to 0.72), respectively.

AUTHORS' CONCLUSIONS

The ESR test does not appear to be sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) appears to be somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevents us from making recommendations at this time. The procalcitonin test seems better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevents us from reaching definitive conclusions. Thus, at present, we do not find any compelling evidence to recommend the routine use of any of these tests in clinical practice.

99mTc-dimercaptosuccinic acid scan versus MRI in pyelonephritis: a meta-analysis

PURPOSE

Tc-dimercaptosuccinic acid (DMSA) scan is the current gold standard in detecting parenchymal changes, particularly scarring, in pyelonephritis. Recently, magnetic resonance imaging (MRI) is gaining popularity in the diagnosis of pyelonephritis. The aim of this study is to perform a meta-analysis on studies directly comparing MRI to DMSA scan in patients with pyelonephritis.

MATERIALS

Systematic searches of PUBMED and EMBASE databases were performed to extract studies comparing MRI and DMSA scan in patients with pyelonephritis. The relevance of articles was assessed by two authors according to predefined inclusion and exclusion criteria. The pooled estimates of the sensitivities of MRI and DMSA scan were computed using random-effects meta-analysis model following DerSimonian and Laird's method. Subgroup analysis and publication bias were performed.

RESULTS

Seven studies were included (164 patients). Using random effect model, the pooled estimate of the sensitivities of MRI and DMSA scan were 0.62 (95%CI: 0.44 - 0.77) and 0.59 (95%CI: 0.48 - 0.70), respectively. The pooled estimates of sensitivities of MRI and DMSA scan for acute pyelonephritis were 0.73 (95%CI: 0.49- 0.89) and 0.66 (95%CI: 0.56 - 0.75), respectively, and for scar detection were 0.48 (95%CI: 0.31- 0.66), and 0.50 (95%CI: 0.30 - 0.71), respectively.

CONCLUSION

The overall sensitivities of MRI and DMSA scan were equivalent in detecting parenchymal changes in pyelonephritis. MRI and DMSA scan appeared to be equivalent to scar detection. In a small number of studies, MRI appeared to be better than the DMSA scan in acute pyelonephritis but this should be further studied in a larger number of patients.

Technetium-99m-dimercaptosuccinic acid renal scintigraphy and single photon emission computed tomography/computed tomography in patients with sickle cell disease

PURPOSE

Sickle cell disease (SCD) is a common hematologic hereditary disorder characterized by vaso-occlusive episodes affecting multiple organs, and substantially alters renal structure and function. We aimed to evaluate the utility of renal scintigraphy and single photon emission computed tomography/computed tomography (SPECT/CT) with technetium-99m-dimercaptosuccinic acid (Tc-DMSA) in adult patients with SCD and no clinical evidence of renal insufficiency.

MATERIALS AND METHODS

Twenty-six patients (16 female) aged 23-58 years with SCD and no clinical evidence of renal insufficiency were prospectively studied. Planar and SPECT/CT images were, respectively, obtained after 3 and 4 hours of the injection of 110-180 MBq of Tc-DMSA. The relative radiopharmaceutical uptake and renal length were, respectively, determined using SPECT and CT images. Planar and SPECT/CT images were visually analyzed to identify focal areas of Tc-DMSA reduced uptake and anatomical deformities of the kidneys.

RESULTS

Focal areas of reduced Tc-DMSA uptake with an image aspect of renal scars or inflammation were present in 21/26 patients (81%). In 11/21 (52%) of these patients, the cortical lesions were clearly identified only on SPECT images. Prominent renal columns were observed in 17/26 (65%) patients. The left kidney tended to be more affected than the right kidney. Most patients had enlarged kidneys.

CONCLUSION

Tc-DMSA scintigraphy and SPECT/CT identify renal lesions possible related to renal infarcts or infections in most adult patients with SCD and no clinical evidence of renal insufficiency. Prominent renal columns and increased renal size tend to occur in most of these patients.

Diffusion-weighted magnetic resonance imaging is more sensitive than dimercaptosuccinic acid scintigraphy in detecting parenchymal lesions in children with acute pyelonephritis: A prospective study

INTRODUCTION

Static renal scintigraphy is the gold standard for detection of inflammatory changes in the renal parenchyma in acute pyelonephritis. Our aim was to determine whether diffusion-weighted magnetic resonance imaging (DW-MRI) was comparable with static renal scintigraphy (DMSA-SRS) to demonstrate acute renal parenchymal lesions.

OBJECTIVE

To compare ^99mTc-dimercaptosuccinic acid static renal scintigraphy (DMSA-SRS) with diffusion-weighted magnetic resonance imaging (DW-MRI) for detecting acute inflammatory changes in the renal parenchyma in children with febrile urinary tract infection.

METHODS

Thirty-one children (30 girls) aged 3-18 years with a first episode of febrile UTI without a previously detected congenital malformation of the urinary tract, were prospectively included. DMSA-SRS and DW-MRI were performed within 5 days of diagnosis to detect renal inflammatory lesions. The DW-MRI examination was performed without contrast agent and without general anesthesia. Late examinations were performed after 6 months using both methods to detect late lesions.

RESULTS

DW-MRI confirmed acute inflammatory changes of the renal parenchyma in all 31 patients (100%), mostly unilateral. DMSA-SRS detected inflammatory lesions in 22 children (71%; p = 0.002). The lesions were multiple in 26/31 children (84%) on DW-MRI and in 9/22 (40%) on DMSA-SRS. At the control examination, scarring of the renal parenchyma was found equally by DW-MRI and DMSA-SRS in five patients (16%), three of whom were the same patients. The overall concordance of positive and negative late findings occurred in 87% of patients. There was correspondence in the anatomical location of acute and late lesions.

DISCUSSION

The clinical significance of acute and late parenchymal findings on DWI-MR is yet to be determined. A limitation of our study is the age of the patients (older than 3 years) who are less sensitive to scar development; therefore, a smaller number of patients with scars could be analyzed during control examination. Further studies using the DW-MRI should confirm its reliability to detect acute and late lesions in younger children and infants and determine the clinical consequences.

CONCLUSION

DW-MRI has higher sensitivity for detecting acute renal inflammatory lesions and multifocal lesions than DMSA-SRS. The incidence of scars was low and corresponded with the anatomical location of acute and late lesions.

Impact of cytokine genetic polymorphisms on the risk of renal parenchymal infection in children

BACKGROUND

Acute pyelonephritis is associated with renal scarring in up to 30% of patients. Renal scarring may cause significant long-term morbidity. The pathogenesis of acute pyelonephritis remains unclear, although it involves interaction among uroepithelium, the immune system cells, and the locally produced cytokines. That some UTI-prone children develop acute pyelonephritis, and eventually renal parenchymal scarring, suggests a genetic role. Interleukin-6, interleukin-8, chemokine receptor-1 (CXCR1), and tumor necrosis factor-alpha (TNFα), the key regulators of the host immune responses, are proteins whose secretion is controlled by genes. We postulated that functional polymorphic variants of their genes might have a role in APN susceptibility.

OBJECTIVES

We sought to investigate a possible association of the common functional polymorphisms in genes encoding IL-6, IL-8, CXCR1, and TNFα with the risk of APN in children.

METHODS

Urine culture was used to diagnose 300 children with UTI, of mean age of 51.31 ± 37.4 months (2-180 months). 99Tc-DMSA scans diagnosed 86 children with APN. Follow-up scans identified new renal scars in 18 children. Six functional single-nucleotide polymorphisms (SNPs) in genes encoding IL-6, IL-8, CXCR1, and TNFα were genotyped in all subjects (IL-6 rs1800795 (-174G/C), IL-6 rs1800796 (-572G/C), IL-8 rs2227306 (781C/T), IL8 rs4073 (-251A/T), CXCR1 rs2234671 (2607G/C), and TNFα rs1800629 (-308G/A)).

RESULTS

TT genotype of IL-8 -251A/T polymorphism was significantly higher in APN patients (26.7%) than those with lower UTI (11.7%, p = 0.01) and control individuals (12.2%, p = 0.002). T allele was significantly more common in APN than in lower UTI (p = 0.025) and was significantly more common in APN (46%) than in the controls (p = 0.001). Similarly, TT genotype of IL-8 781C/T polymorphism was significantly more common in APN patients (31.4%) than those with lower UTI (17.3%, p = 0.003) and the controls (14.3%, p = 0.001). T allele was significantly more common in APN (55%) than lower UTI (40%, p = 0.005) and controls (37%, p = 0.001). However, IL-8 -251A/T and +781C/T SNPs did not qualify as an independent risk for parenchymal infection (OR 1.9, 95% CI 0.68-2.6, p = 0.13 and OR 2.3, 95% CI 0.89-3.7, p = 0.091, respectively). Lower UTI did not differ from the controls. The frequency of the genotypes and alleles of IL-6, CXCR1, and TNFα SNPs did not differ significantly among the different groups of the study.

CONCLUSION

IL-8 -251A/T and +781C/T SNPs are associated with susceptibility to renal parenchymal infection in children and could be implicated in APN risk. However, none of these variants could clearly and independently predict this risk.

Paediatric nuclear medicine imaging

BACKGROUND

Nuclear medicine imaging explores tissue viability and function by using radiotracers that are taken up at cellular level with different mechanism. This imaging technique can also be used to assess blood flow and transit through tubular organs. Nuclear medicine imaging has been used in paediatrics for decades and this field is continuously evolving.

SOURCES OF DATA

The data presented comes from clinical experience and some milestone papers on the subject.

AREAS OF AGREEMENT

Nuclear medicine imaging is well-established in paediatric nephro-urology in the context of urinary tract infection, ante-natally diagnosed hydronephrosis and other congenital renal anomalies. Also, in paediatric oncology, I-123-meta-iodobenzyl-guanidine has a key role in the management of children with neuroblastic tumours. Bone scintigraphy is still highly valuable to localize the source of symptoms in children and adolescents with bone pain when other imaging techniques have failed. Thyroid scintigraphy in neonates with congenital hypothyroidism is the most accurate imaging technique to confirm the presence of ectopic functioning thyroid tissue.

AREAS OF CONTROVERSY

Radionuclide transit studies of the gastro-intestinal tract are potentially useful in suspected gastroparesis or small bowel or colonic dysmotility. However, until now a standardized protocol and a validated normal range have not been agreed, and more work is necessary. Research is ongoing on whether magnetic resonance imaging (MRI), with its great advantage of great anatomical detail and no ionizing radiations, can replace nuclear medicine imaging in some clinical context. On the other hand, access to MRI is often difficult in many district general hospitals and general anaesthesia is frequently required, thus adding to the complexity of the examination.

GROWING POINTS

Patients with bone pain and no cause for it demonstrated on MRI can benefit from bone scintigraphy with single photon emission tomography and low-dose computed tomography. This technique can identify areas of mechanical stress at cortical bone level, difficult to demonstrate on MRI, which can act as pain generators. Positron emission tomography (PET) is being tested in the staging, response assessment and at the end of treatment of several paediatric malignancies. PET is becoming more widely utilized in neurology in the pre-surgical assessment of some children with drug resistant epilepsy.

AREAS TIMELY FOR DEVELOPING RESEARCH

The use of PET/MRI scanners is very attractive as it combines benefits of MR imaging with the assessment of cellular viability and metabolism with PET in one examination. This imaging technique will allow important research on tumour in-vivo metabolism (possible applications include lymphomas, neuroblastomas, malignant germ cell tumours andbrain tumours), with the aim of offering a personalized biological profile of the tumour in a particular patient. Ground-breaking research is also envisaged in neurosciences, especially in epilepsy, using PET tracers that would enable a better identification of the epileptogenic focus, and in psychiatry, with the use of radiolabeled neurotransmitters. In paediatric nephro-urology, the identification of the asymptomatic child with ante-natally diagnosed hydronephrosis at risk of losing renal parenchymal function if left untreated is another area of active research involving radionuclide renography.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

BACKGROUND

In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized.

OBJECTIVES

The objectives of this review were to 1) determine whether procalcitonin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) can replace the acute DMSA scan in the diagnostic evaluation of children with UTI; 2) assess the influence of patient and study characteristics on the diagnostic accuracy of these tests, and 3) compare the performance of the three tests to each other.

SEARCH METHODS

We searched MEDLINE, EMBASE, DARE, Web of Science, and BIOSIS Previews for this review. The reference lists of all included articles and relevant systematic reviews were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We only considered published studies that evaluated the results of an index test (procalcitonin, CRP, ESR) against the results of an acute-phase DMSA scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of UTI. The following cutoff values were used for the primary analysis: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/h for ESR.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate pooled random-effects pooled sensitivity and specificity values.

MAIN RESULTS

A total of 24 studies met our inclusion criteria. Seventeen studies provided data for the primary analysis: six studies (434 children) included data on procalcitonin, 13 studies (1638 children) included data on CRP, and six studies (1737 children) included data on ESR (some studies had data on more than one test). The summary sensitivity estimates (95% CI) for the procalcitonin, CRP, ESR tests at the aforementioned cutoffs were 0.86 (0.72 to 0.93), 0.94 (0.85 to 0.97), and 0.87 (0.77 to 0.93), respectively. The summary specificity values for procalcitonin, CRP, and ESR tests at these cutoffs were 0.74 (0.55 to 0.87), 0.39 (0.23 to 0.58), and 0.48 (0.33 to 0.64), respectively.

AUTHORS' CONCLUSIONS

The ESR test does not appear to be sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) appears to be somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevents us from making recommendations at this time. The procalcitonin test seems better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevents us from reaching definitive conclusions. Thus, at present, we do not find any compelling evidence to recommend the routine use of any of these tests in clinical practice.

Comparison of the Relative Renal Function Calculated with 99mTc-Diethylenetriaminepentaacetic Acid and 99mTc-Dimercaptosuccinic Acid in Children

The aim was to compare the relative renal functions measured with technetium-99m dimercaptosuccinic acid (99mTc-DMSA) and technetium-99m diethylenetriaminepentaacetic acid (99mTc-DTPA) in children with renal diseases. Relative renal function of 128 children who applied to three hospitals from 2009 to 2011 were analyzed retrospectively. The mean value measured with 99mTc-DTPA and 99mTc-DMSA were 51.58 ± 14.95 and 51.96 ± 14.99 for the right kidney, 47.87 ± 15.27 and 47.94 ± 15.17 for the left kidney, respectively. A significant positive correlation was found between the relative renal functions (r = 0.963, P < 0.001). In Bland-Altman plots, the mean difference between two methods was 0.7 and the correlation limits were between 10.1 and-10.8. As a result, although 99mTc-DMSA is accepted as the most reliable method for the determination of relative renal function, 99mTc-DTPA can be another choice for the calculation of relative renal function without a complementary DMSA scan particularly in pediatric patients who require renogram curve and GFR calculations.

Clinical and laboratory indices of severe renal lesions in children with febrile urinary tract infection

AIM

To evaluate the predictive value of various clinical and laboratory parameters on the identification of acute extensive and/or multifocal renal involvement in children with febrile urinary tract infections (UTI).

METHODS

The medical records of 148 children (median age: 2.4 months, range: 11 days-24 months), who were admitted during a 3-year period with a first episode of febrile UTI, were analysed. Acute dimercaptosuccinic acid scintigraphy (DMSA), clinical and laboratory parameters were evaluated.

RESULTS

Seventy six children (51%) had abnormal findings on the acute DMSA. Of them, 20 had DMSA grade 2, while 56 had grade 3 and 4. Patients with a DMSA grade 3 and 4 were more likely to have shivering (OR 3.4), white blood count (WBC) ≥ 18 000/μL (OR 2.4), absolute neutrophil count (ANC) ≥ 9300/μL (OR 4.4), C-reactive protein (CRP) ≥ 50 mg/L (OR 2.7) and procalcitonin (PCT) ≥ 1.64 ng/mL (OR diagnostic). There was a significant difference of WBC (p = 0.004), ANC, CRP and PCT levels (p < 0.001) between children with normal and grade 2 aDMSA versus those with aDMSA grade 3 and 4.

CONCLUSIONS

Shivering and elevated inflammatory markers increase the risk of acute extensive and/or multifocal kidney involvement in children with febrile UTI. Procalcitonin seems to be an excellent marker of the severity of acute parenchymal involvement.

Procalcitonin and C-reactive protein in urinary tract infection diagnosis

BACKGROUND

Urinary infections are a common type of pediatric disease, and their treatment and prognosis are closely correlated with infection location. Common clinical manifestations and laboratory tests are insufficient to differentiate between acute pyelonephritis and lower urinary tract infection. This study was conducted to explore a diagnostic method for upper and lower urinary tract infection differentiation.

METHODS

The diagnostic values of procalcitonin (PCT) and C-reactive protein (CRP) were analyzed using the receiver operating characteristic curve method for upper and lower urinary tract infection differentiation. PCT was determined using chemiluminescent immunoassay.

RESULTS

The PCT and CRP values in children with acute pyelonephritis were significantly higher than those in children with lower urinary tract infection (3.90 ± 3.51 ng/ml and 68.17 ± 39.42 mg/l vs. 0.48 ± 0.39 ng/ml and 21.39 ± 14.92 mg/l). The PCT values were correlated with the degree of renal involvement, whereas the CRP values failed to show such a significant correlation. PCT had a sensitivity of 90.47% and a specificity of 88% in predicting nephropathia, whereas CRP had sensitivity of 85.71% and a specificity of 48%.

CONCLUSIONS

Both PCT and CRP can be used for upper and lower urinary tract infection differentiation, but PCT has higher sensitivity and specificity in predicting pyelonephritis than CRP. PCT showed better results than CRP. PCT values were also correlated with the degree of renal involvement.

Evaluation of interobserver variability of parenchymal phase of Tc-99m mercaptoacetyltriglycine and Tc-99m dimercaptosuccinic acid renal scintigraphy

Objective:

The aim of this study was to investigate the variability in the interpretation of parenchymal abnormalities and to assess the differences in interpretation of routine renal scintigraphic findings on posterior view of technetium-99m dimercaptosuccinic acid (pvDMSA) scans and parenchymal phase of technetium-99m mercaptoacetyltriglycine (ppMAG3) scans by using standard criterions to make standardization and semiquantitative evaluation and to have more accurately correlation.

Materials and Methods:

Two experienced nuclear medicine physicians independently interpreted pvDMSA scans of 204 and ppMAG3 scans of 102 pediatric patients, retrospectively. Comparisons were made by visual inspection of pvDMSA scans, and ppMAG3 scans by using a grading system modified from Itoh et al. According to this, anatomical damage of the renal parenchyma was classified into six types: Grade 0-V. In the calculation of the agreement rates, Kendall correlation (tau-b) analysis was used.

Results:

According to our findings, excellent agreement was found for DMSA grade readings (DMSA-GR) (tau-b = 0.827) and good agreement for MAG3 grade readings (MAG3-GR) (tau-b = 0.790) between two observers. Most of clear parenchymal lesions detected on pvDMSA scans and ppMAG3 scans identified by observers equally. Studies with negative or minimal lesions reduced correlation degrees for both DMSA-GR and MAG3-GR.

Conclusion:

Our grading system can be used for standardization of the reports. We conclude that standardization of criteria and terminology in the interpretations may result in higher interobserver consistency, also improve low interobserver reproducibility and objectivity of renal scintigraphy reports.

The RIVUR trial: profile and baseline clinical associations of children with vesicoureteral reflux

BACKGROUND AND OBJECTIVE

Vesicoureteral reflux (VUR) is diagnosed in ∼30% to 40% of children who have imaging studies after urinary tract infections (UTIs). Our goal is to characterize children enrolled in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial and to compare our study cohort with those from previously published studies.

METHODS

RIVUR investigators from 19 pediatric sites in the United States recruited 607 children with grade I through IV VUR. Children were enrolled after a first or second UTI. This cross-sectional report of baseline data includes extensive clinical, parental report, and imaging study results.

RESULTS

RIVUR recruited 607 children (558 girls, 49 boys) with grade I (11%), II (42%), III (38%), or IV (8%) reflux. The median age was 12 months, and most children (91%) were enrolled after their first UTI. The UTI leading to enrollment was both febrile and symptomatic for 323 children, febrile only in 197 children, and symptomatic only in 86. Renal involvement at baseline as documented by a (99m)Tc dimercaptosuccinic acid scan was uncommon with cortical defects identified in 89 (15%) children. Bladder and bowel dysfunction was identified in 71 (56%) of 126 toilet-trained subjects assessed.

CONCLUSIONS

RIVUR is the largest prospective, randomized trial for children with primary VUR to date, comparing prophylaxis with placebo. The study sample comprises patients from 19 pediatric clinical sites in the United States, whose demographic and clinical characteristics may differ from those of children enrolled in previous trials from other countries.

Is Imaging Time Between two Tc 99m DMSA Scans Sufficient for Reporting as Renal Parenchymal Scarring? Healed Parenchymal Renal Defect After 6 Years

We aimed to report a healed renal parenchymal defect after 6 years in a 9-year-old girl who was being followed for recurrent urinary tract infection (UTI). The first UTI was at the age of two. She was being followed with ultrasonography, urine analysis and urine culture since the first UTI. Technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy was repeated four times up to the present day. She had a renal parenchymal defect reported as parenchymal scarring, which healed 6 years after the first DMSA scintigraphy.

Conflict of interest:None declared.

Hypertension in pediatric patients with renal scarring in association with vesicoureteral reflux

OBJECTIVE

To examine the reflux nephropathy rate and severity as well as the hypertension rate in pediatric patients with vesicoureteral reflux (VUR).

METHODS

The study included 240 patients with VUR. Renal scarring (RS) was demonstrated by renal parenchymal examination using technetium-99m-labeled dimercaptosuccinic acid (99mTc-DMSA) scintigraphy. Office measurements of arterial blood pressure and ambulatory blood pressure monitoring (ABPM) of VUR patients were done during the follow-up period.

RESULTS

Follow-up was a mean duration of 24 months. Rates of RS and hypertension increased parallel to increases in the degree of VUR. A gradual elevation in hypertension rates was evident during the follow-up period. All patients with hypertension had RS. Severe RS in 56 patients was associated with increasing blood pressure readings by 24-hour ABPM or office measurements in 19 patients (33.9%). ABPM measurements enabled us to detect additional patients compared with office measurements alone.

CONCLUSION

Hypertension is a serious complication in children with reflux nephropathy and is associated with the severity of RS and VUR grade. ABPM seems to be superior over office measurements of blood pressure in identifying patients with hypertension.

Identifying children with vesicoureteral reflux: a comparison of 2 approaches

PURPOSE

Various screening approaches have been proposed to identify the subgroup of children with urinary tract infection who have vesicoureteral reflux. However, few studies have compared the sensitivity of screening approaches in a representative population of young children. We compared the sensitivities of the top-down ((99m)technetium dimercaptosuccinic acid renal scan to screen) and biomarker based (C-reactive protein level at presentation) approaches in identifying children with vesicoureteral reflux.

MATERIALS AND METHODS

We calculated the sensitivity of the 2 screening approaches in detecting vesicoureteral reflux and subsequently high grade (III or greater) vesicoureteral reflux in children.

RESULTS

The top-down and C-reactive protein based approaches missed 33% and 29% of cases of high grade vesicoureteral reflux, respectively.

CONCLUSIONS

The sensitivity of the top-down approach for detecting high grade vesicoureteral reflux was lower than previously reported. Further study of novel methods to identify children at risk for renal scarring is warranted.

Common and less-common renal masses and masslike conditions

As an increasing number of imaging examinations are performed, a greater number of incidental renal lesions are detected. Apart from the usual cysts and solid renal cell carcinomas, a variety of unusual benign and malignant renal lesions exist. Imaging is invaluable in characterizing these lesions and is confirmatory in some benign lesions. Renal cell carcinoma remains the diagnosis of exclusion; however, assessment of the imaging pattern in the appropriate clinical context can improve diagnostic accuracy. The objective of this article is to familiarize the radiologist with the imaging appearance of unusual non-neoplastic and neoplastic lesions and correlate with histopathologic studies when available.

Discordant findings on dimercaptosuccinic acid scintigraphy in children with multi-detector row computed tomography-proven acute pyelonephritis

PURPOSE

The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of (99m)Tc-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT).

METHODS

We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ≥2 years (n=36).

RESULTS

Among total 81 patients with MDCT-proven APN. DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male with average age of 21 months and most of them, 19 (73.1%) were <2 years of age.

CONCLUSION

DMSA scan has obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.

Candida urinary tract infections--diagnosis

The finding of candiduria in a patient with or without symptoms should be neither dismissed nor hastily treated, but requires a careful evaluation, which should proceed in a logical fashion. Symptoms of Candida pyelonephritis, cystitis, prostatitis, or epididymo-orchitis are little different from those of the same infections produced by other pathogens. Candiduria occurring in critically ill patients should initially be regarded as a marker for the possibility of invasive candidiasis. The first step in evaluation is to verify funguria by repeating the urinalysis and urine culture. Pyuria is a nonspecific finding; the morphology of the offending yeast may allow separation of Candida glabrata from other species. Candida casts in the urine are indicative of renal candidiasis but are rarely seen. With respect to culture, colony counts have not proved to be diagnostically useful. In symptomatic or critically ill patients with candiduria, ultrasonography of the kidneys and collecting systems is the preferred initial study. However, computed tomography (CT) is better able to discern pyelonephritis or perinephric abscess. The role of magnetic resonance imaging and renal scintigraphy is ill defined, and prudent physicians should consult with colleagues in the departments of radiology and urology to determine the optimal studies in candiduric patients who require in-depth evaluation.

Can Tc 99m DTPA be Used in Adult Patients in Evaluation of Relative Renal Function Measurement as the Reference Tc 99m DMSA Method?

Objective: In the literature, there are many reports comparing relative renal function calculated with Tc 99m DTPA and Tc 99m DMSA in adults and children. However, there is no consensus about the results. As there is indeterminacy in the reliability of Tc 99m DTPA for the calculation of the relative renal functions, we retrospectively designed a study to compare the relative renal functions measured with Tc 99m DMSA and Tc 99m DTPA in adult patients with renal diseases

Material and Methods: We retrospectively analyzed the data of 144 patients who applied to Nuclear Medicine Department of three hospitals between 2009 and 2010 and who had both dynamic and static renal imaging. Renal dynamic scintigraphies were compared to the relative function measured using Tc 99m DMSA static scintigraphy. Comparison of relative renal function measurements using dynamic and static renal scintigraphies was performed using Pearson correlation test. The comparison results were expressed with Bland-Altman analysis.

Results: The study was conducted with 144 patients and 288 kidneys. Fifty six of patients were male. Mean age was 39.9±15.2 years. Thirty four patients had hydronephrosis, 28 pyelonephritis, 53 renal calculi, 3 chronic renal failure, 2 acute renal failure, 1 benign renal neoplasia, 15 renal atrophy, 8 ureteropelvic junction stenosis. Relative renal function was calculated in Tc 99m DMSA and 99m Tc-DTPA studies. The mean relative renal functions measured with Tc 99m DTPA was 52.54±23.09% and 47.25±23.09, with Tc 99m DMSA 52.85±21.80% and 47.07±21.77% for right and left kidneys, respectively. In bivariate correlation analysis (Pearson) a significant positive correlation was found between the relative renal functions calculated with Tc 99m DTPA and Tc 99m DMSA (r =0.937, p< 0.001). In Bland-Altman plots, the mean difference between two methods was 0.3 and the correlation limits were between 16.2 to -15.5.

Conclusion: As a result, we concluded that Tc 99m DTPA is also a good method for the relative renal function evaluation when compared to Tc 99m DMSA scan. Although Tc 99m DMSA is the most reliable method for the calculation of relative renal function, Tc 99m DTPA can be another choice for the calculation of relative renal function without a complementary DMSA scan particularly in patients who require renogram curve and GFR calculations.

Conflict of interest:None declared.

The Bnai Zion Planar Method: a simplified technique for the quantitation of the absolute renal uptake of (99m)Tc-DMSA in children

AIM AND PURPOSE

Radionuclide imaging of the kidneys using dimercaptosuccinic acid chelate labeled with technetium-99m (Tc-DMSA) is a well-established method for evaluating the extent of kidney parenchymal involvement in the scenario of urinary tract infection and for the estimation of the functional renal mass. We have developed a simplified technique, Bnai Zion Planar Method (BZPM), to estimate absolute DMSA uptake by the kidneys, which uses a shorter time of acquisition and does not require cumbersome calculations of attenuation correction. The aim of this study was to validate this technique by comparing it with the Quantitative DMSA single-photon emission computed tomography (SPECT) (QDMSA) measurements as the reference method.

METHODS

Sixty-one consecutive children (mean age 5.4+/-4.8 years) were included in the study. Absolute uptake of the radiopharmaceutical by the kidneys was measured using the QDMSA SPECT methods described earlier with data acquisition of 20 min. Kidney volumes and radioactivity concentration measurements were calculated on the reconstruction data using the threshold method. For the simplified technique (BZPM), a planar posterior view of the kidneys was acquired for 1 min at the end of the QDMSA SPECT study.

RESULTS

In both kidneys we observed a significant strong correlation between the two methods. BZPM measurements were very similar to those obtained using the validated QDMSA method, as determined by linear regression analysis (Pearson's r=0.924, P<0.001), r(2)=0.854. The uptake according to QDMSA can be predicted by the uptake measured by the BZPM method using the following regression equation: QDMSA=0.445+1.061 BZPM.

CONCLUSION

BZPM estimation in children using the newly proposed planar method was found to be nearly identical to the validated QDMSA SPECT method.

Procalcitonin as a marker of severe bacterial infection in children in the emergency department

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

Urinary proteins in children with urinary tract infection

The aim of this study was to test our hypothesis that the urinary excretion of C-reactive protein (CRP), alpha 1-microglobulin (A1M), retinol-binding protein (RBP) and Clara cell protein (CC16) is increased in children with urinary tract infection (UTI) and relates to renal damage as measured by acute dimercaptosuccinic acid (DMSA) scintigraphy. Fifty-two children <2 years of age with UTI were enrolled in the study, 44 of whom were febrile. The control group consisted of 23 patients with non-UTI infection and elevated serum CRP (s-CRP) levels. Thirty-six patients had abnormal DMSA uptake, classified as mild, moderate or severe damage (DMSA class 1, 2, 3, respectively). There was a significant association between DMSA class and the excretion of urinary RBP (u-RBP) and u-CC16. There was also a significant difference in u-CRP levels between children with UTI and control children with non-UTI infections, although u-CRP excretion was not significantly correlated to DMSA class. In conclusion, the urinary excretion of the low-molecular-weight proteins RBP and CC16 showed a strong association with uptake defects on renal DMSA scans. The urinary level of CRP seems to distinguish between children with UTI and other febrile conditions. A combination of these biomarkers may be useful in the clinical assessment of children with UTI.

Renal power Doppler ultrasound does not predict renal scarring after urinary tract infection

OBJECTIVE

Young children may develop renal scarring following a urinary tract infection (UTI) especially after pyelonephritis which is difficult to diagnose. Permanent renal scars are diagnosed by dimercapto-succinic acid (DMSA) scan several months later. To decrease unnecessary exposure to radiation, we investigate the role of renal power Doppler (RPD) in predicting those who may not require a late DMSA scan.

METHODS

Children under four years of age with a first UTI underwent an RPD study soon after diagnosis, and a DMSA scintigraphy six months later. The predictive values of the early RPD to detect DMSA renal scarring were calculated.

RESULTS

Twenty three children (median age 30 months) were enrolled: 13 had a febrile presentation, two with bacteraemia. Permanent scarring occurred in three children (13%). In the 46 kidney units studied, initial RPD was abnormal in two and late DMSA abnormal in three units. Overall concordance between RPD and DMSA was 93.5%. The sensitivity of RPD for renal scar as per DMSA was 33.3%, specificity 97.7%; positive predictive value 50% and a negative predictive value of 95.4%.

CONCLUSIONS

RPD offered no advantage over ultrasound to predict renal scarring and cannot be recommended to predict renal scarring following UTI.

Value of comprehensive renal ultrasound in children with acute urinary tract infection for assessment of renal involvement: comparison with DMSA scintigraphy and final diagnosis

The aim of this study was to evaluate the value of comprehensive renal ultrasound (US), i.e., combining greyscale US and amplitude-coded color Doppler sonography (aCDS), for assessment of urinary tract infection (UTI) in infants and children, compared to (1) (99m)Tc DMSA scintigraphy and (2) final diagnosis. Two hundred eighty-seven children with UTI underwent renal comprehensive US and DMSA scintigraphy. The results were compared with regard to their reliability to diagnose renal involvement, using (1) DMSA scintigraphy and (2) final diagnosis as the gold standard. Sixty-seven children clinically had renal involvement. Sensitivity increased from 84.1% using only aCDS to 92.1% for the combined US approach, using DMSA scintigraphy as the reference standard. When correlated with the final diagnosis, sensitivity for DMSA scintigraphy was 92.5%; sensitivity for comprehensive US was 94.0%. Our data demonstrate an increasing sensitivity using the combination of renal greyscale US supplemented by aCDS for differentiation of upper from lower UTI. Sensitivity for DMSA and comprehensive US was similar for both methods compared to the final diagnosis. Comprehensive US should gain a more important role in the imaging algorithm of children with acute UTI, thereby reducing the radiation burden.

Prospective, randomized trial comparing short and long intravenous antibiotic treatment of acute pyelonephritis in children: dimercaptosuccinic acid scintigraphic evaluation at 9 months

OBJECTIVE

We report a prospective, randomized, multicenter trial that compared the effect of 3 vs 8 days of intravenous ceftriaxone treatment on the incidence of renal scarring at 6 to 9 months of follow-up in 383 children with a first episode of acute pyelonephritis.

METHODS

After initial treatment with intravenous netilmicin and ceftriaxone, patients were randomly assigned to either 5 days of oral antibiotics (short intravenous treatment) or 5 days of intravenous ceftriaxone (long intravenous treatment). Inclusion criteria were age 3 months to 16 years and first acute pyelonephritis episode, defined by fever of >38.5 degrees C, C-reactive protein level of >20 mg/L, and bacteriuria at >10(5)/mL. All patients underwent 99m technetium-dimercaptosuccinic acid scintigraphy 6 to 9 months after inclusion. A total of 548 children were included, 48 of whom were secondarily excluded and 117 of whom were lost to follow-up or had incomplete data; therefore, 383 children were eligible, 205 of them in the short intravenous treatment group and 178 in the long intravenous treatment group.

RESULTS

At inclusion, median age was 15 months, median duration of fever was 43 hours, and median C-reactive protein level was 122 mg/L. A total of 37% (143 of 383) of patients had a vesicoureteral reflux grades 1 to 3. Patient characteristics at inclusion were similar in both groups, except for a significantly higher proportion of girls in the short intravenous treatment group. The frequency of renal scars at scintigraphy was similar in both groups. Multivariate analysis demonstrated that renal scars were significantly associated with increased renal height at initial ultrasound and with the presence of grade 3 vesicoureteric reflux.

CONCLUSIONS

The incidence of renal scars was similar in patients who received 3 days compared 8 days of intravenous ceftriaxone. Increased renal height at initial ultrasound examination and grade 3 vesicoureteric reflux were significant risk factors for renal scars.

Pyelonephritis, renal scarring, and reflux nephropathy: a pediatric urologist's perspective

Imaging of children with a clinical diagnosis of pyelonephritis is performed to characterize the extent of the infection, to identify associated renal injury and to uncover risk factors for future infections and renal damage. Although there is general agreement regarding the need for parenchymal imaging and the need to exclude processes that are either functionally or anatomically obstructive, there is controversy regarding the need for routine cystography, especially when parenchymal involvement has not been documented. A protocol that limits the use of cystography for evaluation of urinary tract infections must assume that the diagnosis of reflux is at least of variable clinical significance. It is now clear that vesicoureteral reflux and reflux nephropathy represent a diverse population that includes both congenital and acquired processes. MR imaging will improve our understanding of vesicoureteral reflux, pyelonephritis and renal scarring and might help us to identify and manage those patients most at risk for recurrent infections and renal injury. To recognize the potential contributions of this newer imaging technique it is helpful to look at our understanding of the pathophysiology of pyelonephritis, reflux and reflux nephropathy.

Normal dimercaptosuccinic acid scintigraphy makes voiding cystourethrography unnecessary after urinary tract infection

OBJECTIVE

To test the hypothesis that infants with dilating vesicoureteral reflux (VUR) have abnormal acute dimercaptosuccinic acid (DMSA) scintigraphy results, as was suggested by an earlier retrospective study.

STUDY DESIGN

We conducted a prospective study of infants <1 year old with first diagnosed symptomatic urinary tract infection at the Children's Hospital of Göteborg, Sweden. Two hundred ninety consecutive children (161 boys and 129 girls) with complete records were examined. Renal ultrasound scanning and DMSA scintigraphy were performed within a few days from diagnosis, and VCU was performed within 2 months.

RESULTS

VUR was found in 52 children, of which 27 had dilating VUR (grade III-V). DMSA scintigraphy results were abnormal in 149 infants (51%), 105 of 238 (44%) without VUR, 18 of 25 (72%) with VUR grade I to II, and 26 of 27 (96%) with VUR grade III to V (P <.001).

CONCLUSION

DMSA scintigraphy results were abnormal in all 27 infants with dilating VUR except 1. This single false-negative finding should be compared with 140 unnecessary VCU investigations. This supports our hypothesis that DMSA scintigraphy results are abnormal when there is dilating VUR. Thus, a normal DMSA scan makes VCU unnecessary in the primary examination of infants with UTI.

Childhood acute pyelonephritis: comparison of power Doppler sonography and Tc-DMSA scintigraphy

BACKGROUND

Tc 99m DMSA scintigraphy is regarded as the gold standard for the detection and localization of acute pyelonephritis (APN) in children. Power Doppler sonography (PD US) is a radiation-free and cost-effective technique that could be useful in the diagnosis of APN in children.

OBJECTIVE

To compare the predictive value of PD US with DMSA scintigraphy in the diagnosis of APN in children.

MATERIALS AND METHODS

A total of 74 neonates and children with clinical findings consistent with possible upper urinary tract infection were evaluated with PD US and DMSA scintigraphy. Children with anatomic (grey-scale) abnormalities were excluded. A total of 147 kidneys were examined within the first 48 h after the onset of symptoms. Each kidney was divided into three zones (upper, middle, and lower third).

RESULTS

APN was diagnosed by PD US in 46 kidneys. Sensitivity and specificity for detecting APN using DMSA scintigraphy as the reference standard were 73.8% and 85.7%, respectively. There was good agreement between PD US and DMSA scintigraphy in the localization of lesions.

CONCLUSION

In clinically suspected APN, PD US has acceptable specificity and sensitivity, if performed within the first 48 h and could be helpful in neonates and children under 3 months of age in whom the use of scintigraphy is generally discouraged.

Renal pseudotumors

OBJECTIVE

Renal cell carcinoma is the most common malignant tumor to involve the kidneys; however, a number of other entities--called renal pseudotumors--may mimic renal neoplasms on imaging. This article presents the imaging features and pathologic correlation of some of the common and uncommon renal pseudomasses.

CONCLUSION

Many renal lesions look similar to renal cell carcinoma on radiologic imaging. The imaging features of renal pseudotumors presented in this article will help radiologists to identify them and to triage these patients for appropriate management.

Accurate diagnosis of acute pyelonephritis: How helpful is procalcitonin?

AIM

This prospective study aimed to investigate the diagnostic value of serum procalcitonin levels in children with acute pyelonephritis documented by Tc-dimercaptosuccinic acid (DMSA) scintigraphy.

METHODS

We compared the symptoms and laboratory findings of fever, vomiting, abdominal/flank pain, leukocyte count, serum C-reactive protein and procalcitonin levels with the results of the DMSA scan obtained within the first 72 h after referral in children who were diagnosed as having acute pyelonephritis. Thirty-three children (31 female and two male) aged 1-11 years (mean 4.42 years) were enrolled in this prospective study.

RESULTS

Twenty-one of 33 patients (64%) had positive DMSA scans. On the scans obtained after 6 months, five of 21 patients (23.8%) had renal scars. No correlation was found between clinical and laboratory parameters, alone or combined with each other, and positive DMSA scans. Serum procalcitonin levels were 0.767+/-0.64 and 1.23+/-1.17 ng . ml in children with normal and positive DMSA scans, respectively. The cut-off value for procalcitonin using receiver operating characteristic analysis was 0.9605 ng . ml, while sensitivity and specificity were 86.4% and 36.4%, respectively. However, if the cut-off value was chosen as 2 ng . ml, the sensitivity increased to 100% while specificity did not change markedly.

CONCLUSION

The serum procalcitonin test, like other commonly used laboratory parameters, e.g. serum C-reactive protein and white blood cell count, was inadequate in distinguishing renal parenchymal involvement in acute febrile urinary tract infections.

Resolution of cortical lesions on serial renal scans in children with acute pyelonephritis

BACKGROUND

The ideal time for distinguishing a renal scar from acute inflammatory lesions by renal DMSA scintigraphy remains controversial.

OBJECTIVE

To determine the time needed for resolution of lesions after acute pyelonephritis.

MATERIALS AND METHODS

A total of 105 children with acute pyelonephritis underwent renal sonography, voiding cystourethrography and baseline DMSA scintigraphy. Two subsequent scans were performed during the 6th and 12th months in patients with abnormal findings on the previous scan.

RESULTS

The baseline DMSA scintigraphy revealed cortical lesions in 37 patients. At 6 months, 13 patients (38.2%) were found to have cortical lesions. At 12 months, 6 patients (17.6%) were found to have persistent renal cortical lesions. The resolution rates for lesions detected on the first scan were 61.8% and 82.4% on the 6- and 12-month scans, respectively. Vesicoureteric reflux, and bilaterality or multifocality were not relevant for resolution of lesions. Female gender seemed to be associated with a higher persistence rate.

CONCLUSIONS

The renal cortical defects present at 6 months have a high rate of resolution later during follow-up. DMSA scintigraphy performed 12 months after the infection provides more reliable data regarding persistence of renal cortical lesions.

Power Doppler sonographic evaluation of acute childhood pyelonephritis

Urinary tract infection is common in children. The available gold standard methods for diagnosis, Tc-99m dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) are invasive and expensive. This study was performed to assess the role of power Doppler ultrasound (PDU) for diagnosis of acute pyelonephritis (APN) compared with Tc-99m DMSA scan. A prospective study was conducted in 34 children with the mean age of 2.8+/-2.7 years who were hospitalized with the first episode of febrile urinary tract infection. All children were examined in the first 3 days of admission by PDU and Tc-99m DMSA scan. Patients with congenital structural anomaly were excluded. Each kidney was divided into three zones. The comparison between PDU and DMSA scan was performed on the basis of patients and renal units. According to the patient's number, sensitivity, specificity, positive and negative predictive values, and accuracy of PDU were 89%, 53%, 70%, 80%, and 74%, respectively, but based on the renal units, changed to 66%, 81%, 46%, 91%, and 79%, respectively. Although PDU has the potential for identifying APN in children, it is still soon to replace DMSA scan.

Effect of percutaneous nephrolithotripsy on renal function: assessment with quantitative SPECT of (99m)Tc-DMSA renal scintigraphy

PURPOSE

To measure the effect of PCNL on global and regional renal function using quantitative single-photon emission CT (SPECT) measurement of Tc-dimercaptosuccinic acid (DMSA) uptake by the kidneys (QDMSA).

PATIENTS AND METHODS

A series of 47 male and 41 female patients with a mean age of 47 +/- 16 years were studied by sequential QDMSA examinations before and 1.5 to 24 months after PCNL. Among the 67 patients (76%) in whom PCNL was performed using upper- or lower-pole access, the function of the affected and nonaffected poles of the treated kidney was calculated separately.

RESULTS

There was no statistically significant difference in the uptake by the treated kidneys before versus after PCNL (11.9% +/- 5% v 11.6% +/- 5%; t = 0.9; P = 0.368). The total functional volume of the treated kidney was slightly decreased, from 235 cc +/- 62 cc to 224 cc +/- 59 cc (t = 2.7; P = 0.011). The percent of the injected isotope dose per cubic centimeter of tissue of the treated kidney was not affected (0.051 +/- 0.02 v 0.053 +/- 0.02; t = 0.86; P = 0.296). Regional assessment revealed a statistically significant decrease in the functional volume at the PCNL port of entry (91 cc +/- 30 cc v 82 cc +/- 27 cc; t = 2.64; P = 0.013). Regarding the percent of the injected dose per cubic centimeter of renal tissue, no statistically significant difference was found between the area of the kidney that underwent PCNL and the untreated area of the same kidney (0.049 +/- 0.02 v 0.05 +/- 0.02; t = 0.693; P = 0.494). The function of the contralateral kidneys remained unchanged (13.4% +/- 5.2% v 13.6% +/- 4.8%; t = 0.68; P = 0.5).

CONCLUSIONS

Despite the statistically significant decrease in the functional volume of the surgically treated region, neither total percent uptake nor percent of injected dose were reduced significantly. Further studies with long-term follow-up of treated kidneys are required.

Preliminary evaluation of 99mTechnetium diethylenetriamine pentaacetic acid, 99mTechnetium dimercaptosuccinic acid, and 99mTechnetium mercaptoacetyltriglycine for renal scintigraphy in corn snakes (Elaphe guttata guttata)

The efficacy of three radiopharmaceuticals, 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA), 99mTc-dimercaptosuccinic acid (99mTc-DMSA), and 99mTc-mercaptoacetyltriglycine (99mTc-MAG3), for renal imaging was examined in 16 corn snakes (Elaphe guttata guttata). All snakes received the radiopharmaceutical via an intracardiac injection. The kidneys could not be visualized in the three snakes that received 99mTc-DTPA or in the three snakes that received 99mTc-DMSA, but were well delineated in all 10 snakes receiving 99mTc-MAG3. These snakes were anesthetized and a dynamic frame mode acquisition was obtained for 30 min immediately following injection. A 60 s single static frame mode image was then obtained with the snake in a curled position. Two of the 10 snakes that received 99mTc-MAG3 were removed from further analysis because of suspected pericardial injections. Of the remaining eight snakes, the mean (+/- SD) renal uptake was 25 +/- 9.8% or 24 +/- 9.7%, with or without correction for residual injection site activity, respectively. Correction for remaining radioactivity in the heart does not appear to be necessary if it is less than 10% of the total dose. 99mTc-MAG3 provided consistently high quality images of the kidneys and further studies are warranted to evaluate its sensitivity for detecting decreased function in snakes with renal disease.

Effectiveness of diuretic injection on the measurement of differential renal function using Tc-99m DMSA in patients with a dilated renal pelvis

AIM

The aim of this study was to evaluate the effectiveness of diuretic injection for the measurement of differential renal function (DRF) with technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy in patients with a dilated pelvis.

MATERIALS AND METHODS

A total of 46 patients who were referred for both technetium-99m-L,L-ethylenedicysteine (Tc-99m L,L-EC) and Tc-99m DMSA imaging and found to have a dilated collecting system on Tc-99m EC scintigraphy were studied. Four to 5 hours after intravenous injection of Tc-99m DMSA, imaging was performed in the supine position, and posterior, anterior, left and right lateral, and left and right posterior oblique views were taken. After this study, furosemide was administered intravenously and 30 minutes later, additional images in the anterior and posterior views were obtained.

RESULTS

The kidneys were evaluated into 2 groups. Group 1 comprised 12 kidneys that had an obstructive curve pattern on Tc-99m EC scans. Group 2 comprised 34 kidneys that had a nonobstructive dilated renogram curve pattern. DRF of the kidneys in each patient were calculated, and the values obtained from the standard and diuretic DMSA scans were compared with each other for all patients and each group. Considering all the patients, the values of mean DRF on both standard and diuretic DMSA images were 55.4%+/-21.2% and 55.4%+/-21.5%, respectively. There were no significant differences between DRF values of each kidney obtained by the 2 methods. When we compared the DRF values in groups 1 and 2, there were again no significant differences. In group 1, the values of mean DRF on standard and diuretic images were 51.7%+/-13.7% and 51.6%+/-13.9%, respectively, and in group 2, the values of mean DRF were 56.7%+/-23.4% and 56.7%+/-23.6%, respectively.

CONCLUSION

In view of our study, diuretic administration seems to be an unnecessary intervention because it has no effect on the accuracy of DRF measurements using DMSA scintigraphy in patients with a dilated collecting system whether it is obstructed or not.

Mechanisms of renal damage owing to infection

Urinary tract infection (UTI) is a common bacterial illness in children. It is known to be associated with an increased risk of permanent renal cell damage and scarring which may lead to generation of pathological conditions such as hypertension, pre-eclampsia during pregnancy, renal insufficiency, and end-stage kidney disease. The pathophysiology of renal scarring is still obscure, which makes the prevention of renal damage difficult. During acute infection, there are numerous factors that may contribute to tissue damage. Inflammatory responses are activated by host defense mechanisms as well as by specific bacterial virulence factors. Understanding of these complex mechanisms would be helpful to better identify children at high risk of developing renal scarring following UTI.

Diagnosis and management of pediatric urinary tract infections

Urinary tract infection (UTI) is among the most commonly diagnosed bacterial infections of childhood. Although frequently encountered and well researched, diagnosis and management of UTI continue to be a controversial issue with many challenges for the clinician. Prevalence studies have shown that UTI may often be missed on history and physical examination, and the decision to screen for UTI must balance the risk for missed infections with the cost and inconvenience of testing. Interpretation of rapid diagnostic tests and culture is complicated by issues of contamination, false test results, and asymptomatic colonization of the urinary tract with nonpathogenic bacteria. The appropriate treatment of UTI has been controversial and has become more complex with the emergence of resistance to commonly used antibiotics. Finally, the anatomic evaluation and long-term management of a child after a UTI have been based on limited evidence, and newer studies question some of the tenets of prior recommendations. The goal of this review is to provide an up-to-date summary of the literature with particular attention to practical questions about diagnosis and management for the clinician.