OBJECTIVE: In the current clinical practice, administered activity (AA) for pediatric molecular imaging is often based on the North American expert consensus guidelines or the European Association of Nuclear Medicine dosage card, both of which were developed based on the best clinical practice. These guidelines were not formulated using a rigorous evaluation of diagnostic image quality (IQ) relative to AA. In the guidelines, AA is determined by a weight-based scaling of the adult AA, along with minimum and maximum AA constraints. In this study, we use task-based IQ assessment methods to rigorously evaluate the efficacy of weight-based scaling in equalizing IQ using a population of pediatric patients of different ages and body weights.
METHODS: A previously developed projection image database was used. We measured task-based IQ, with respect to the detection of a renal functional defect at six different AA levels (AA relative to the AA obtained from the guidelines). IQ was assessed using an anthropomorphic model observer. Receiver-operating characteristics (ROC) analysis was applied; the area under the ROC curve (AUC) served as a figure-of-merit for task performance. In addition, we investigated patient girth (circumference) as a potential improved predictor of the IQ.
RESULTS: The data demonstrate a monotonic and modestly saturating increase in AUC with increasing AA, indicating that defect detectability was limited by quantum noise and the effects of object variability were modest over the range of AA levels studied. The AA for a given value of the AUC increased with increasing age. The AUC vs AA plots for all the patient ages indicate that, for the current guidelines, the newborn and 10- and 15-yr phantoms had similar IQ for the same AA suggested by the North American expert consensus guidelines, but the 5- and 1-yr phantoms had lower IQ. The results also showed that girth has a stronger correlation with the needed AA to provide a constant AUC for 99m Tc-DMSA renal SPECT.
CONCLUSIONS: The results suggest that (a) weight-based scaling is not sufficient to equalize task-based IQ for patients of different weights in pediatric 99m Tc-DMSA renal SPECT; and (b) patient girth should be considered instead of weight in developing new administration guidelines for pediatric patients.

OBJECTIVE: In a historical cohort of children with a urinary tract infection (UTI) who had already undergone all the imaging procedures, the aim was to determine renal tract abnormalities which would have been missed had we implemented the new guidelines from the National Institute for Health and Care Excellence in the United Kingdom (NICE) or the American Academy of Pediatrics (AAP).
METHODS: After a UTI episode, forty-three children (28 females, 65%) aged between 2 months and 2 years presenting at two general hospitals with a febrile UTI before 2008 underwent all the recommended imaging studies predating the new guidelines. Hydronephrosis was defined and graded according to the Society for Fetal Urology (SFU) classification. Hydronephrosis grade II (mild pelvicalyceal dilatation), grade III (moderate dilatation), and grade IV (gross dilatation with thinning of the renal cortex), duplication, vesicoureteral reflux (VUR) grade II and above, renal scarring and reduced renal uptake (<45%) on technetium-99m-labeled dimercaptosuccinic acid (DMSA) scintigraphy were considered significant abnormalities. We calculated the proportion of abnormalities which would have been missed had the new guidelines been used instead.
RESULTS: The median of age was 7.6 months (mean 8.7, range 2-24 months), with the majority (n = 37, 86%) being under 1 year of age. Ultrasound (US) showed hydronephrosis in 14 (32%), all grade II. A voiding cystourethrogram (VCUG) was performed in all and showed VUR ≥ grade II in 16 (37%), including eight children (19%) where it was bilateral. DMSA scan showed scarring in 25 children (58%) of whom 11 (26%) had bilateral scars. Reduced differential renal uptake was present in 10 children (23%). Of the 29 children with normal US, 18 (62%) had renal scarring and nine (31%) had VUR ≥ grade II. The NICE guidelines would have missed 63% of the children with VUR ≥ grade II, including a high proportion of grades IV and V VUR, 44% of the children with renal scarring, and 20% of the children with decreased renal uptake, including some children with bilateral renal scarring and with decreased renal uptake. The AAP guidelines would have missed 56% of the children with VUR ≥ grade II, including a high proportion of grades IV and V VUR, and all children with renal scarring as well as those with decreased renal uptake.
CONCLUSIONS: The prevalence of renal tract abnormalities missed by the new guidelines is high. They should be used with full awareness of their limitations.

BACKGROUND: We examined the ability of a procalcitonin (PCT) protocol to detect vesicoureteral reflux (VUR) and renal scarring (RS), evaluated procedural costs and radiation burden, and compared four representative guidelines for children with their first febrile urinary tract infection (UTI).
METHODS: Children aged ≤2 years with their first febrile UTI who underwent renal ultrasonography (US), acute and late technetium-99m ((99m)Tc)-dimercaptosuccinic acid scan, and voiding cystourethrography were prospectively studied. The representative guidelines applied in a retrospective simulation included the American Academy of Pediatrics (AAP), National Institute of Clinical Excellence, top-down approach (TDA), and Italian Society of Pediatric Nephrology (ISPN). These were compared in terms of ability to detect abnormalities, procedural costs and radiation.
RESULTS: Of 278 children analyzed, 172 (61.9%) had acute pyelonephritis. There was VUR in 101 (36.3%) children, including 73 (26.3%) with grades III-V VUR. RS was identified in 75 (27.0%) children. To detect VUR, TDA and PCT had the highest sensitivity for grades I-V VUR (80.2%) and III-V VUR (94.5%), respectively, whereas AAP had the highest specificity for I-V VUR (77.4%) and III-V VUR (78.0%), respectively. TDA and PCT had the highest sensitivity (100%) for detecting RS. The highest cost and radiation dose was associated with TDA, whereas AAP had the least expenditure and radiation exposure. By multivariate analysis, PCT and VUR, especially grades III-V, were independent predictors of RS.
CONCLUSIONS: There is no perfect guideline for first febrile UTI children. The PCT protocol has good ability for detecting high-grade VUR and RS. If based on available imaging modalities and reducing cost and radiation burden, clinical suggestions in the AAP guidelines represent a considerable protocol.

OBJECTIVE: To compare the childhood urinary tract infection (UTI) guidelines from the Royal College of Physicians (RCP) in 1991 and from National Institute of Health and Care Excellence (NICE) (CG54) in 2007 by measuring their efficiency at detecting urinary tract abnormalities.
METHODS: Children with UTIs within the Newcastle Primary Care Trust (population 70,800 children) were referred and imaged according to the RCP guidelines during 2008, and these were compared to the activity that would have been undertaken if we had implemented the CG54 guidelines, including following them through 2011 to identify those with recurrent UTIs.
METHODS: The numbers of children imaged, the imaging burden and efficiency, and urinary tract abnormalities detected by each guideline.
RESULTS: Fewer children would have been imaged by CG54 than RCP (150 vs 427), but its sensitivity was lower, at 44% for detecting scarring, 10% for identifying vesicoureteric reflux and 40% for other abnormalities. Overall, it would have only detected one-quarter of the abnormal cases (8 vs 32) and would have missed five of nine children with scarring, including three with multiple lesions and one with renal impairment. Imposing an age restriction of <8 years to the RCP guidelines would reduce its screening rate by 20% and still detect 90% of the abnormalities.
CONCLUSIONS: The CG54 guidelines do not alter the imaging efficiency compared to the RCP guidelines, but they are considerably less sensitive.

暂无摘要。

暂无摘要。

OBJECTIVE: To assess the outcome of imaging investigations carried out in children with urinary tract infection (UTI), to compare the investigations with national guidelines, and to assess the impact on management.
METHODS: Retrospective review of inpatients and outpatients, aged 0-12 years, referred to the University Hospital of Wales Healthcare Trust between February 1997 and January 1998 with UTI. All children without bacterial evidence of UTI and children previously investigated for antenatal urological anomalies, major congenital anomalies, or UTI were excluded.
RESULTS: A total of 164 children (51 boys, 113 girls) were included. Thirteen of 56 infants (23%) and 82/108 older children (76%) were diagnosed at home over one year. The prevalence of dilatation on ultrasound was 8%, renal scarring on dimercaptosuccinic acid (DMSA) scan was 11%, and vesicoureteric reflux (VUR) was 34% when investigations were carried out following guidelines published by the Royal College of Physicians. In children aged 1-6 years, the prevalence of scarring was 1/54 (2%) in those treated at home and 6/18 (33%) in inpatients.
CONCLUSIONS: The low yield of positive results and lack of evidence of impact on management indicate that DMSA scanning, with all the implications of isotope exposure, intravenous injection, staff time, psychological trauma, and expense, could be omitted in children over 1 year with first simple UTI not sufficiently ill to be admitted to hospital. The low rate of detection of UTI in primary care in infants may represent under diagnosis.

There are considerable variations in the management of children with urinary tract infection and reflux. These new guidelines were written after critical review of the literature, but are also based on clinical experience, since there are issues that have not been otherwise adequately studied. The aim is to limit renal damage and future complications, with minimal discomfort to the child, and to avoid unnecessary costs. The recommendations include increased attention to bladder dysfunction, shortening of the time of antibacterial prophylaxis and focus on renal development and function rather than on reflux.

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99mTc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99mTc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.

暂无摘要。