Renal stone detection using a low kilo-voltage paediatric CT protocol – A porcine phantom study

yesIntroduction: Reducing tube voltage is an effective dose saving method in computed tomography (CT) assuming tube current is not concurrently increased. Recent innovations in scanner technology now enable CT tube voltage reduction to 70 kV thereby increasing opportunities for dose reduction in paediatric patients, but it is unclear if the increased image noise associated with 70 kV impacts on ability to visualise renal stones accurately. The purpose was to assess detectability of nephrolithiasis using a bespoke paediatric phantom and low kV, non-contrast CT and to assess inter-observer agreement. Methods: Forty-two renal stones of different size and chemical composition were inserted into porcine kidneys and positioned in a bespoke, water-filled phantom mimicking a 9-year-old child weighing approximately 33kg. The phantom was scanned using 120 and 70 kV CT protocols, and the detectability of the stones was assessed by three radiologists. Absolute agreement and Fleiss’ kappa regarding detectability were assessed. Results: The mean diameter of renal stones as measured physically was 4.24 mm ranging from 1 to 11 mm. Four stones were missed by at least one observer. One observer had a sensitivity of 93 and 95% at 70 and 120 kV, respectively, while the sensitivity for observers 2 and 3 was 98% at both kV levels. Specificity was 100% across readers and kV levels. Absolute agreement between the readers at 70 kV was 92% (kappa = 0.86) and 98% (kappa = 0.96) at 120 kV indicating a strong agreement at both kV levels. Conclusions: The results suggest that lowering the kV does not affect the detection rate of renal stones and may be a useful dose reduction strategy for assessment of nephrolithiasis in children

Can dual CT with fast kV-switching determine renal stone composition accurately?

noRationale and Objectives: To determine whether a single source computed tomography (CT) system utilizing fast kV switching and low dose settings can characterize (diameter and chemical composition) renal stones accurately when compared infrared spectroscopy. Materials and Methods: The chemical composition of 15 renal stones was determined using Fourier transform infrared spectroscopy. The stones were inserted into a porcine kidney and placed within a water tank for CT scanning using both fast kV switching dual energy and standard protocols. Effective atomic number of each stone was measured using scanner software. Stone diameter measurements were repeated twice to determine intra-rater variation and compared to actual stone diameter as measured by micro CT. Results: The chemical composition of three stones (one calcium phosphate and two carbonite apatite) could not be determined using the scanner software. The composition of 10/12 remaining stones was correctly identified using dual energy computed tomography (83% absolute agreement; k = 0.69). No statistical difference (p = 0.051) was noted in the mean stone diameter as measured by clinical CT and micro CT. Conclusion: Dual energy computed tomography using fast kV switching may potentially be developed as a low dose clinical tool for identifying and classifying renal stones in vivo supporting clinical decision-making

Complications associated with ureterorenoscopy (URS) related to treatment of urolithiasis: the Clinical Research Office of Endourological Society URS Global study

INTRODUCTION: Ureterorenoscopy (URS) is a popular and growing option for management of ureteric and renal stones. The CROES URS Global Study was set up to assess the outcomes of URS in a large worldwide cohort of patients involving multiple centres. In this paper, we analysed the database for intra-operative and post-operative complications associated with ureterorenoscopy.METHODS: The CROES database was established via collaboration between 114 centres in 32 countries worldwide, and information on both intra-operative and post-operative complications was collected electronically between January 2010 and October 2012.RESULT: On analysis of a total of 11,885 patients, the overall complication and stone-free rates were found to be 7.4 and 85.6 %, respectively. The intra-operative and post-operative complication rates were 4.2 and 2.6 %, respectively, and in total 5 deaths were reported in the study period. Taking into account different world economies, there were no differences in the complication rates between the developing and developed nations or between different centres from different continents.CONCLUSION: Ureterorenoscopy is a safe and effective procedure for treatment of stones, the outcomes of which are broadly comparable in different parts of the world for similar patient and stone demographics.</p

In vitro and in vivo behaviors of the three-layered nanocarbonated hydroxyapatite/collagen/PLGA composite

10.1177/0883911509358811Journal of Bioactive and Compatible Polymers252154-168JBCP

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study

What’s known on the subject? and What does the study add?Scientists have found a number of genetic factors that increase prostate cancer risk, including heritable mutations in the genes BRCA1 and BRCA2. These mutations are not common but can have major impact, as a BRCA2 mutation increases risk by up to seven-fold while a BRCA1 mutation is thought to double risk in men under 65. The IMPACT study aims to determine whether targeted screening in men with a known BRCA1 or BRCA2 mutation would lead to earlier diagnosis of prostate cancers.This data from the IMPACT study adds to the increasing evidence that BRCA mutation carriers develop more aggressive disease. Although these are early results, it appears that PSA screening is more accurate at predicting potentially aggressive prostate cancer among men at higher risk of the disease due to a genetic predisposition than general population screening. This study provides support for continued screening in men with genetic mutations.Objective: To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported.Patients and methods: Men aged 40–69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA &gt;3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation.Results: In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant.Conclusions: The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.<br/