Renal fibrosis: prediction from acute pyelonephritis focus volume measured at 99mTc dimercaptosuccinic acid SPECT

Risk factors for new renal scarring in children with vesicoureteral reflux receiving continuous antibiotic prophylaxis

To investigate the risk factors for new renal scarring (NRS) in children with vesicoureteral reflux (VUR) receiving continuous antibiotic prophylaxis (CAP). This was a single-center cohort study. The clinical data of 140 children with grade I-V VUR receiving CAP were analyzed. In this study, exposure variables were sex, younger age at the initial diagnosis of UTI ≤ 12 months, the occurrence of breakthrough urinary tract infection (BT-UTI), high-grade VUR, bilateral VUR, etiology, presence of renal scarring at the initial diagnosis and ultrasound abnormalities. The outcome was NRS. A total of 140 children were included in the risk factor analysis of NRS, 73 of whom experienced NRS, an incidence rate of 52.14%. Multivariate Cox regression suggested that the presence of renal function impairment after the initial diagnosis of UTI (OR 3.411, 95% CI 1.5751-6.646) and the occurrence of BT-UTI while receiving CAP (OR 1.995, 95% CI 1.089-2.958) were independent risk factors for NRS. Multivariate Cox regression showed that high-grade VUR had no significant effects on NRS (OR 0.940, 95% CI 0.462-1.912, P = 0.864). No significant difference was identified in multivariate Cox regression analysis in the IV-V group (vs I-III group) (OR 0.960, 95% CI 0.565-1.633, P = 0.960). Renal function impairment after the initial diagnosis of UTI and the occurrence of BT-UTI while receiving CAP were independent risk factors for NRS. Neither univariate analysis nor multivariate analysis found a correlation between VUR grade and NRS.

Differentiation between normal and abnormal kidneys using 99mTc-DMSA SPECT with deep learning in paediatric patients

AIM

To investigate the feasibility of using deep learning (DL) to differentiate normal from abnormal (or scarred) kidneys using technetium-99m dimercaptosuccinic acid (99mTc-DMSA) single-photon-emission computed tomography (SPECT) in paediatric patients.

MATERIAL AND METHODS

Three hundred and one 99mTc-DMSA renal SPECT examinations were reviewed retrospectively. The 301 patients were split randomly into 261, 20, and 20 for training, validation, and testing data, respectively. The DL model was trained using three-dimensional (3D) SPECT images, two-dimensional (2D) maximum intensity projections (MIPs), and 2.5-dimensional (2.5D) MIPs (i.e., transverse, sagittal, and coronal views). Each DL model was trained to determine renal SPECT images into either normal or abnormal. Consensus reading results by two nuclear medicine physicians served as the reference standard.

RESULTS

The DL model trained by 2.5D MIPs outperformed that trained by either 3D SPECT images or 2D MIPs. The accuracy, sensitivity, and specificity of the 2.5D model for the differentiation between normal and abnormal kidneys were 92.5%, 90% and 95%, respectively.

CONCLUSION

The experimental results suggest that DL has the potential to differentiate normal from abnormal kidneys in children using 99mTc-DMSA SPECT imaging.

Reducing scan time of paediatric 99mTc-DMSA SPECT via deep learning

AIM

To investigate the feasibility of reducing the scan time of paediatric technetium 99m (^99mTc) dimercaptosuccinic acid (DMSA) single-photon-emission computed tomographic (SPECT) using a deep learning (DL) method.

MATERIAL AND METHODS

A total of 112 paediatric ^99mTc-DMSA renal SPECT scans were analysed retrospectively. Of the 112 examinations, 88 (84 for training and four for validation) were used to train a DL-based model that could generate full-acquisition-time reconstructed SPECT images from half-time acquisition. The remaining 24 examinations were used to evaluate the performance of the trained model.

RESULTS

DL-based SPECT images obtained from half-time acquisition have image quality similar to the standard clinical SPECT images obtained from full-acquisition-time acquisition. Moreover, the accuracy, sensitivity and specificity of the DL-based SPECT images for detection of affected kidneys were 91.7%, 83.3%, and 100%, respectively.

CONCLUSION

These preliminary results suggest that DL has the potential to reduce the scan time of paediatric ^99mTc-DMSA SPECT imaging while maintaining diagnostic accuracy.

Semiquantitative analysis of power doppler ultrasonography versus Tc-99m DMSA scintigraphy in diagnostic and severity assessment of acute childhood pyelonephritis

BACKGROUND

This study aimed to compare the diagnostic and predictive value of power Doppler ultrasonography (PDU) with Tc-99m dimercaptosuccinic acid (DMSA) renal scintigraphy in pediatric acute pyelonephritis (APN) using a semiquantitative analysis system.

METHODS

A total of 92 children and infants (184 kidneys) were hospitalized with possible APN. All children were examined by PDU and DMSA scintigraphy within 72 hours of admission. An empiric 9-point semiquantitative analysis system was used to sort kidneys into four grades (grade 0-III). Patients with several episodes of APN and congenital structural anomalies were excluded.

RESULTS

Of 184 kidneys, we found 68 abnormal (grade I-III) and 116 normal (Grade 0) with DMSA scintigraphy, and 84 abnormal and 100 normal with PDU. In all, 23 kidneys were shown to be diseased by PDU but normal on DMSA scintigraphy while 7 kidneys showed the opposite trend. The sensitivity and specificity of PDU for diagnosing APN was 89.7% and 80.2%, respectively (P<0.05). In children older than 6 months, the sensitivity was higher (92%, P<0.05) than that in children younger than 6 months (87%, P<0.05). A moderate agreement (41%, P<0.05) on grade was found between the two methods.

CONCLUSIONS

With the help of a semiquantitative analysis system, PDU can obviate the use of DMSA scintigraphy in children older than 6 months for APN diagnosis.

Predictors of Renal Dysfunction in Adults with Childhood Vesicoureteral Reflux after Long-Term Follow-Up

BACKGROUND:

Triad of childhood vesicoureteral reflux (VUR), urinary infection (UTI) and renal scarring might initiate potentially serious consequences that lead to renal dysfunction manifested at the second or third decade of life.

AIM:

To identify the risk factors predictive for renal dysfunction in adults with primary VUR after long-term follow-up.

METHODS:

We evaluated the records of 101 children (94.1% female, 5.9% male) at a median age of 5.2 ± 2.3 years (1-12 years), suffering from UTI and VUR. The patients were interviewed after mean 21 years from the first episodes of VUR (8 to 32 years). Renal function was determined from the estimated glomerular filtration rate (eGFR).

RESULTS:

Renal scarring was detected in 68.3% out of 82 patients and bilateral one in 7.3% patients. Linear regression analysis revealed that presence of proteinuria (B = -33.7, p=0.0001), the greater number of years from VUR diagnosis (B = -1.6, p = 0.002) and renal scarring (B = -14.8, p = 0.005) appeared as independent predictors of reduced global eGFRcreat. The same variables plus microalbuminuria (B = -1.0, p = 0.012) appeared as independent predictors of reduced global eGFRcreat-cys. Bilateral scarring (OR=25.5, p = 0.003) appeared as independent predictor of greater risk for CKD assessed using eGFRcreat while greater number of years from VUR diagnosis (OR = 1.7, p = 0.092), microalbuminuria (OR = 1.3, p = 0.047) and again bilateral scarring (OR = 31.3, p = 0.040) appeared as predictors of risk for CKD assessed using eGFRcreat-cys.

CONCLUSION:

Identification of those with an increased risk of progression to CKD should be the goal in all patients with childhood VUR. Their systematic follow-up should be till adulthood and older age.

Evaluation of new American Academy of Pediatrics guideline for febrile urinary tract infection

PURPOSE

To evaluate the practical applications of the diagnosis algorithms recommended by the American Academy of Pediatrics urinary tract infection (UTI) guideline.

METHODS

We retrospectively reviewed the medical records of febrile UTI patients aged between 2 and 24 months. The patients were divided into 3 groups: group I (patients with positive urine culture and urinalysis findings), group II (those with positive urine culture but negative urinalysis findings), and group III (those with negative urine culture but positive urinalysis findings). Clinical, laboratory, and imaging results were analyzed and compared between the groups.

RESULTS

A total of 300 children were enrolled. The serum C-reactive protein level was lower in children in group II than in those in groups I and III (P<0.05). Children in group I showed a higher frequency of hydronephrosis than those in groups II and III (P<0.05). However, the frequencies of acute pyelonephritis (APN), vesicoureteral reflux (VUR), renal scar, and UTI recurrence were not different between the groups. In group I, recurrence of UTI and presence of APN were associated with the incidence of VUR (recurrence vs. no recurrence: 40% vs.11.4%; APN vs. no APN: 23.3% vs. 9.2%; P<0.05). The incidence of VUR and APN was not related to the presence of hydronephrosis.

CONCLUSION

UTI in febrile children cannot be ruled out solely on the basis of positive urinalysis or urine culture findings. Recurrence of UTI and presence of APN may be reasonable indicators of the presence of VUR.

Risk factors for renal scarring and deterioration of renal function in primary vesico-ureteral reflux children: a long-term follow-up retrospective cohort study

BACKGROUND AND PURPOSE

The aim was to identify the risk factors for renal scarring and deteriorating renal function in children with primary vesico-ureteral reflux (VUR).

MATERIALS AND METHODS

Patients with primary VUR admitted to the National Cheng Kung University Hospital were retrospectively analyzed. The outcomes were renal scarring, assessed by technetium-99 m dimercaptosuccinic acid scanning, and renal function, assessed by estimated glomerular filtration rate. Univariate and multivariate models were applied to identify the corresponding independent predictors.

RESULTS

A total of 173 patients with primary VUR were recruited. The median age of VUR diagnosis was 10.0 months (IQR: 4.0-43.0 months). After adjusting for confounding factors, it was found that older age of VUR diagnosis (≥5 years vs. <1 year, adjusted OR = 2.78, 95% CI = 1.00-7.70, p = 0.049), higher grade of VUR (high grade [IV-V] vs. none, adjusted OR = 15.17, 95% CI = 5.33-43.19, p<0.0001; low grade [I-III] vs. none, adjusted OR = 5.72, 95% CI = 2.43-13.45, p<0.0001), and higher number of UTI (≥2 vs. 0, adjusted OR = 3.21, 95% CI = 1.06-9.76, p = 0.039) were risk factors for renal scarring, whereas a younger age of VUR diagnosis (≥5 years vs. <1 year, adjusted HR = 0.16, 95% CI: 0.05-0.51, p = 0.002), renal scarring (yes vs. no, adjusted HR = 3.66, 95% CI: 1.32-10.16, p = 0.013), and APN (yes vs. no, adjusted HR = 3.10, 95% CI: 1.05-9.14, p = 0.041) were risk factors for developing chronic kidney disease stage 2 or higher.

CONCLUSIONS

Our findings expand on the current knowledge of risk factors for renal scarring and deteriorating renal function, and this information can be used to modify the management and treatment of VUR.

Nephromegaly is a significant risk factor for renal scarring in children with first febrile urinary tract infections

PURPOSE

We determined whether nephromegaly on ultrasound can be used to identify patients with urinary tract infection at increased risk for renal scarring, and we investigated the effect of vesicoureteral reflux on renal scarring.

MATERIALS AND METHODS

We enrolled hospitalized patients with a first febrile urinary tract infection. All patients underwent renal ultrasound and most patients underwent voiding cystourethrography. Renal scarring was assessed using (99m)technetium dimercapto-succinic acid renal scintigraphy at least 6 months after treatment. Children with recurrent urinary tract infections before scintigraphy were excluded from the study.

RESULTS

A total of 545 children (80 with and 465 without nephromegaly) were enrolled. Infection was more severe in patients with than without nephromegaly. The incidence of renal scarring was significantly higher in patients with nephromegaly (90% vs 32%, p <0.001), in kidneys with nephromegaly (80.5% vs 18.7%, p <0.001) and in kidneys with vesicoureteral reflux (41.5% vs 22.2%, p <0.001). Kidneys with nephromegaly had a greater incidence of reflux. The finding of nephromegaly is associated with a greatly increased likelihood of renal scarring in patients with vesicoureteral reflux.

CONCLUSIONS

Our results indicate that ultrasound diagnosis of nephromegaly at onset is associated with a high incidence of renal scarring, and identification of nephromegaly at onset and vesicoureteral reflux are significant risk factors for renal scarring in children with a first febrile urinary tract infection. Nephromegaly is associated with an increased frequency of vesicoureteral reflux and increased likelihood of renal scarring in patients with reflux.

Adjunctive oral methylprednisolone in pediatric acute pyelonephritis alleviates renal scarring

OBJECTIVE

To determine if glucocorticoids can prevent renal scar formation after acute pyelonephritis in pediatric patients.

METHODS

Patients younger than 16 years diagnosed with their first episode of acute pyelonephritis with a high risk of renal scar formation (ie, inflammatory volume ≥ 4.6 mL on technetium-99m-labeled dimercaptosuccinic acid scan [DMSA] or abnormal renal ultrasonography results) were randomly assigned to receive either antibiotics plus methylprednisolone sodium phosphate (1.6 mg/kg per day for 3 days [MPD group]) or antibiotics plus placebo (placebo group) every 6 hours for 3 days. Patients were reassessed by using DMSA 6 months after treatment. The primary outcome was the development of renal scars.

RESULTS

A total of 84 patients were enrolled: 19 in the MPD group and 65 in the placebo group. Patient characteristics were similar between the 2 groups, including the acute inflammatory parameters and the initial DMSA result. Renal scarring was found in 33.3% of children treated with MPD and in 60.0% of those who received placebo (P < .05). The median cortical defect volumes on follow-up DMSA were 0.0 mL (range: 0-4.5 mL) and 1.5 mL (range: 0-14.8 mL) for the MPD and placebo groups, respectively (P < .01). Patients in the MPD group experienced faster defervescence after treatment than the placebo group.

CONCLUSIONS

Adjunctive oral MPD therapy reduced the occurrence and/or severity of renal scarring after acute pyelonephritis in these hospitalized children who had a high risk of renal scar formation.

Acute lobar nephronia is associated with a high incidence of renal scarring in childhood urinary tract infections

BACKGROUND

Acute lobar nephronia (ALN) is a severe nonliquefactive inflammatory renal bacterial infection, and requires a longer duration of treatment. The aim of this prospective study was to investigate renal scarring after ALN and to examine the risk factors for renal scarring in children with ALN compared with those with acute pyelonephritis (APN).

METHODS

Patients with computed tomography-diagnosed ALN were enrolled and randomly allocated, with serial entry, to either a 2- or 3-week antibiotic treatment regimen. Age- and gender-matched APN patients served as comparators. Patients underwent dimercaptosuccinic acid scintigraphy at least 6 months later to assess renal scarring.

RESULTS

A total of 218 children (109 ALN, 109 APN) were enrolled. The incidence of renal scarring was similar between 2- and 3-week treatment groups and was higher in ALN patients than in APN patients (89.0% vs. 34.9%, P < 0.001). Renal scarring was prone to occur in children with higher inflammatory indices and longer duration of fever before and after treatment. Multiple regression analysis on independent variables showed that only ALN was significantly associated with a higher incidence of renal scarring.

CONCLUSIONS

Our results showed a new finding that ALN is associated with a very high incidence of renal scarring, in comparison to APN, irrespective of the duration of antibiotic treatment.

Vitamin E administration at the onset of fever prevents renal scarring in acute pyelonephritis

We evaluated the protective effects of antioxidant at the onset of fever on renal damage in a rat model of acute pyelonephritis. Twenty rats were allocated to four groups. In groups 1 to 3, the animals were given direct inoculation of Escherichia coli into the right kidney, and group four served as control. All rats in groups 1 to 3 were given once-daily intraperitoneal injections of ceftriaxon for five consecutive days, beginning on the third day after inoculation. The animals' body temperatures were monitored; as soon as body temperature reaches 38 degrees C, the rats in group 2 were given allopurinol co-treatment, whereas, in group 3, vitamin E co-treatment was started at fever onset. Both kidneys were excised 6 weeks later, for the evaluation of histopathologic changes, apoptotic damage, and concentrations of transforming growth factor-beta (TGF-beta). Only minimal changes were found in control samples. Pathologic scores of inflammation and fibrosis in group 1 were higher than in the vitamin E and allopurinol groups (P < 0.05). Apoptosis index was also decreased in groups 2 and 3, compared to group 1 (P < 0.05). There was no significant difference in average TGF-beta levels between study groups. These findings suggest that administration of vitamin E or allopurinol following the onset of fever can reduce renal damage in pyelonephritis.

Renal scarring sequelae in childhood Kawasaki disease

To assess renal inflammation and its sequelae in Kawasaki disease (KD) patients, we conducted a prospective study in a university medical center setting in Taiwan. From June 2002 to January 2005, 50 children with KD were enrolled, and after admission, all received technetium-99m dimercaptosuccinic acid scintigraphy single photon emission computed tomography (DMSA renal SPECT), the results of which were used as the reference standard for determining renal inflammation. Patients with renal inflammation underwent another DMSA renal SPECT more than 6 months later to evaluate the sequelae. We found that 26 of the 50 patients (52%) had renal inflammatory foci. There were no significant relationships between clinical or laboratory parameters and renal involvement in KD, except the presence of coronary artery lesions [P<0.01; odds ratio (OR) 5.18; 95% confidence interval (CI) 1.52-17.65]. Although all patients were free of clinical symptoms, the 6-month follow-up DMSA renal SPECT showed renal scarring in 11 of the 24 patients (46%). Patients with an initial abnormal renal ultrasound did predict a greatly increased risk of scarring (P<0.05; OR 16.2; 95% CI 1.27-206.20). In conclusion, this study demonstrated that the potential long-term clinical impact of KD is not limited to coronary artery lesion sequelae but also includes renal scar formation.

Multi-detector row CT systems and image-reconstruction techniques

The introduction in 1998 of multi-detector row computed tomography (CT) by the major CT vendors was a milestone with regard to increased scan speed, improved z-axis spatial resolution, and better utilization of the available x-ray power. In this review, the general technical principles of multi-detector row CT are reviewed as they apply to the established four- and eight-section systems, the most recent 16-section scanners, and future generations of multi-detector row CT systems. Clinical examples are used to demonstrate both the potential and the limitations of the different scanner types. When necessary, standard single-section CT is referred to as a common basis and starting point for further developments. Another focus is the increasingly important topic of patient radiation exposure, successful dose management, and strategies for dose reduction. Finally, the evolutionary steps from traditional single-section spiral image-reconstruction algorithms to the most recent approaches toward multisection spiral reconstruction are traced.

Evaluation of kidney damage in patients with acute lymphoblastic leukemia in long-term follow-up: value of renal scan

In order to evaluate potential long-term kidney damage of childhood leukemia and risk factors affecting renal damage, we studied 116 children treated for acute lymphoblastic leukemia (ALL) using the St. Jude Total XI and XIII protocols in 1991-1998. The median follow-up period after the completion of treatment was 35 months. The following parameters were examined: urinalysis, urinary creatinine (Cr), calcium (Ca), phosphorus, beta2-microglobulin, glomerular filtration rate (GFR), tubular phosphorus reabsorption (TPR), and renal function tests. Radiological evaluation included renal ultrasonography (US), and renal scans with DMSA or MAG-3 were performed. Blood chemistry and renal US patients were normal in all patients except two. GFR, TPR, urinary Ca/Cr, beta2-microglobulin, and renal scan were abnormal in 19.0%, 16.4%, 13.8%, 6.0%, and 40.5% of patients, respectively. The abnormality rate in GFR was significantly higher in patients <2 years of age. TPR abnormality was found to be significantly higher in patients who did not have G-CSF. An abnormal renal scan was associated with Hb < 10 g/dL, kidney infiltration, or hypertension at presentation and also occurred patients who underwent methotrexate treatment with frequent intervals during the follow-up period. Patients should be followed-up after cessation of therapy with the conventional tests mentioned above. In case of any abnormality, further detailed tests should be performed; renal scan seems to be more predictive for renal damage.

Acute pyelonephritis and sequelae of renal scar in pediatric first febrile urinary tract infection

To investigate the incidence of acute pyelonephritis (APN) and renal scarring in children with febrile urinary tract infection (UTI), 191 of 216 (88%) children with their first episode of UTI received (99m)Tc-dimercaptosuccinic acid renal single-photon emission computed tomography. They were investigated within 7 days of admission and were followed for 6 months. One hundred and six patients (49.1%) underwent a voiding cystourethrogram. The incidence of vesicoureteric reflux (VUR) in group I (</=1 year old) was 22%, group II (1-5 years old) 69%, and group III (5-17 years old) 44%. The overall incidence of APN in febrile UTI was 70% (male 66%, female 76%, P=0.110). Children had a higher incidence of APN than infants ( P<0.05 in group I vs. II and group I vs. III). Of patients with APN, 57% (35/61) showed renal scar formation. VUR was found in 31%(24/78) of children with APN and 58% (14/24) of children with renal scar. In addition, children with high-grade VUR were more susceptible to APN and scar formation than those with low-grade VUR ( P<0.05). Older children with a first febrile UTI had a higher incidence of APN than infants (</=1 year), and half of the children with APN developed a renal scar.