Cornelius Lewis

Multicentre prospective survey of SeHCAT provision and practice in the UK.

Objective A clinical diagnosis of bile acid malabsorption (BAM) can be confirmed using SeHCAT (tauroselcholic (75selenium) acid), a radiolabelled synthetic bile acid. However, while BAM can be the cause of chronic diarrhoea, it is often overlooked as a potential diagnosis. Therefore, we investigated the use of SeHCAT for diagnosis of BAM in UK hospitals. Design A multicentre survey was conducted capturing centre and patient-level information detailing patient care-pathways, clinical history, SeHCAT results, treatment with bile acid sequestrants (BAS), and follow-up in clinics. Eligible data from 38 centres and 1036 patients were entered into a validated management system. Results SeHCAT protocol varied between centres, with no standardised patient positioning, and differing referral systems. Surveyed patients had a mean age of 50 years and predominantly women (65%). The mean SeHCAT retention score for all patients was 19% (95% CI 17.8% to 20.3%). However, this differed with suspected BAM type: type 1: 9% (95% CI 6.3% to 11.4%), type 2: 21% (95% CI 19.2% to 23.0%) and type 3: 22% (95% CI 19.6% to 24.2%). Centre-defined ‘abnormal’ and ‘borderline’ results represented over 50% of the survey population. BAS treatment was prescribed to only 73% of patients with abnormal results. Conclusions The study identified a lack of consistent cut-off/threshold values, with differing centre criteria for defining an ‘abnormal’ SeHCAT result. BAS prescription was not related in a simple way to the SeHCAT result, nor to the centre-defined result, highlighting a lack of clear patient care-pathways. There is a clear need for a future diagnostic accuracy study and a better understanding of optimal management pathways.

A Multicenter Prospective Study to Investigate the Diagnostic Accuracy of the SeHCAT Test in Measuring Bile Acid Malabsorption: Research Protocol

Background Bile acid malabsorption (BAM) is one possible explanation for chronic diarrhea. BAM may be idiopathic, or result from ileal resection or inflammation including Crohn’s disease, or may be secondary to other conditions, including cholecystectomy, peptic ulcer surgery, and chronic pancreatitis. No “gold standard” exists for clinical diagnosis of BAM, but response to treatment with a bile acid sequestrant (BAS) is often accepted as confirmation. The SeHCAT (tauroselcholic [selenium-75] acid) test uses a radiolabeled synthetic bile acid and provides a diagnostic test for BAM, but its performance against “trial of treatment” is unknown. Fibroblast growth factor 19 (FGF-19) and 7-alpha-hydroxy-4-cholesten-3-one (C4) also offer potential new biomarkers of BAM. Objective This protocol describes a multicenter prospective study to evaluate the diagnostic accuracy of SeHCAT and 2 biomarkers in predicting BAM as assessed by trial of treatment. Methods Participating gastroenterology centers should have a minimum workload of 30 SeHCAT patients per annum. Patients should not be pregnant, on medication that could confound follow-up, or have any severe comorbidity. All eligible patients attending a gastrointestinal appointment will be invited to participate. On attending the SeHCAT test, blood and fecal samples will be collected for analysis of FGF-19 by enzyme-linked immunosorbent assay and for C4 and fractionated bile acids by liquid chromatography–mass spectrometry. A capsule containing radiolabeled SeHCAT will be administered orally and a scan performed to measure SeHCAT activity. Patients will return on day 7 to undergo a second scan to measure percentage SeHCAT retention. The test result will be concealed from clinicians and patients. BAS will be dispensed to all patients, with a follow-up gastroenterologist appointment at 2 weeks for clinical assessment of treatment response and adherence. Patients responding positively will continue treatment for a further 2 weeks and all patients will have a final follow-up at 8 weeks. The diagnostic accuracy of the SeHCAT test and biomarkers will be analyzed at different thresholds using sensitivity, specificity, positive and negative predictive value, likelihood ratios, and area under the curve in a sample of 600 patients. Multivariable logistic regression models will be used to assess the association between presence of BAM and continuous SeHCAT retention levels after adjustment for confounders. Results Funding is being sought to conduct this research. Conclusions The SeHCAT test for diagnosis of BAM has been in common use in the United Kingdom for more than 30 years and an evidence-based assessment of its accuracy is overdue. The proposed study has some challenges. Some forms of BAS treatment are unpleasant due to the texture and taste of the resin powder, which may negatively affect recruitment and treatment adherence. Trial of treatment is not as “golden” a standard as would be ideal, and itself warrants further study.

Optimisation of Radiation Protection in Diagnostic Radiology

The basic framework for Radiation Protection, according to ICRP, is based on three fundamental principles; justification, optimisation and limitation. The second principle, optimisation, is where the medical physicist can have the greatest influence. Briefly, the principle states that doses should be kept As Low as Reasonably Achievable (ALARA).

EMITEL e-Encyclopaedia of Medical Physics - Project Development and Future

The e-Encyclopaedia for Medical Physics with Multilingual Dictionary EMITEL has been launched 6 months ago (www.emitel2.eu). This international project attracted more than 250 specialists from 35 countries and established itself as the largest international project in the profession. The paper describes the main phases of EMITEL, its current use and the planned future development.