Study design for concurrent development, assessment, and implementation of new diagnostic imaging technology

With current constraints on health care resources and emphasis on value for money, new diagnostic imaging technologies must be assessed and their value demonstrated. The state of the art in the field of diagnostic imaging technology assessment advocates a hierarchical step-by-step approach. Although rigorous, such a hierarchical assessment is time-consuming, and, given the current rapid advances in technology, results are often too late to influence management and policy decisions. The purpose of this article is to discuss a study design in which development, assessment, and implementation of new diagnostic imaging technology take place concurrently in one integrated process. An empirically based pragmatic study design is proposed for imaging technology assessment. To minimize bias and enable comparison with current technology, a randomized controlled design is used whenever feasible and ethical. Outcome measures should reflect the clinical decision-making process based on imaging information and acceptance of the new test. Outcome measures can include additional imaging studies requested, costs of diagnostic work-up and treatment, physicians' confidence in therapeutic decision making, recruitment rate, and patient outcome measures related to the clinical problem. The key feature of the proposed study design is analysis of trends in outcome measures over time

Peripheral arterial disease: gadolinium-enhanced MR angiography versus color-guided duplex US--a meta-analysis

PURPOSE: To summarize and compare the published data on gadolinium-enhanced magnetic resonance (MR) angiography and color-guided duplex ultrasonography (US) for the work-up for peripheral arterial disease. MATERIALS AND METHODS: Studies published between January 1984 and November 1998 were included if (a) gadolinium-enhanced MR angiography and/or color-guided duplex US were performed for evaluation of arterial stenoses and occlusions in the work-up for peripheral arterial disease of the lower extremities, (b) conventional angiography was the reference standard, and (c) absolute numbers of true-positive, false-negative, true-negative, and false-positive results were available or derivable. RESULTS: With a random effects model, pooled sensitivity for MR angiography (97.5% [95% CI: 95.7%, 99.3%]) was higher than that for duplex US (87.6% [95% CI: 84.4%, 90.8%]). Pooled specificities were similar: 96.2% (95% CI: 94.4%, 97.9%) for MR angiography and 94.7% (95% CI: 93.2%, 96.2%) for duplex US. Summary receiver operating characteristic analysis demonstrated better discriminatory power for MR angiography than for duplex US. Regression coefficients for MR angiography versus US were 1.67 (95% CI: -0.23, 3.56) with adjustment for covariates, 2.11 (95% CI: 0.12, 4.09) without such adjustment, and 1.73 (95% CI: 0.44, 3.02) with a random effects model. CONCLUSION: Gadolinium-enhanced MR angiography has better discriminatory power than does color-guided duplex US and is a highly sensitive and specific method, as compared with conventional angiography, for the work-up for peripheral arterial disease

When is Better Best? A multiobjective perspective

Purpose: To identify the most informative methods for reporting results of treatment planning comparisons. Methods: Seven papers from the past year of International Journal of Radiation Oncology Biology Physics reported on comparisons of treatment plans for IMRT and IMAT. The papers were reviewed to identify methods of comparisons. Decision theoretical concepts were used to evaluate the study methods and highlight those that provide the most information. Results: None of the studies examined the correlation between objectives. Statistical comparisons provided some information but not enough to make provide support for a robust decision analysis. Conclusion: The increased use of treatment planning studies to evaluate different methods in radiation therapy requires improved standards for designing the studies and reporting the results

Cost and patency rate targets for the development of endovascular devices to treat femoropopliteal arterial disease

PURPOSE: To determine the criteria that would make use of an endovascular device cost-effective compared with bypass surgery and percutaneous transluminal angioplasty in the treatment of femoropopliteal arterial disease. MATERIALS AND METHODS: A decision model was developed to compare treatment with the use of a hypothetical endovascular device with established therapies. Cost-effectiveness from the perspective of the health care system was considered. Outcome measures were lifetime costs and quality-adjusted life-years. With the use of net health benefit calculations and threshold analysis, combinations of costs and patency rates were determined that would make the device cost-effective compared with established therapies. In subgroup and sensitivity analyses, the effect on decision-making of sex, age, indication, lesion type, procedural risk, and society's willingness to pay for incremental gain in health were explored. RESULTS: Use of a device that costs $3,000 would be cost-effective compared with bypass surgery for critical ischemia if the 5-year patency rate is 29%-46%. Use of the same device would be cost-effective compared with angioplasty for disabling claudication and stenosis if the 5-year patency rate is 69%-86%. CONCLUSION: The target combinations of costs and patency rates found in this study are probably attainable, and further development of such endovascular devices seems warranted

Effects of saline reclaimed waters and deficit irrigation on Citrus physiology assessed by UAV remote sensing

The aim of our research was to discover the effects of the long-term irrigation with saline reclaimed (RW) and transfer (TW) water and different irrigation strategies: control (C) and regulated deficit irrigation (RDI) on yield and fruit quality of grapefruit at harvest and during cold storage. TW-RDI treatment decreased tree canopy (TC) and crop load, resulting in a 21% reduction of fruit yield. Regarding fruit quality, RW notably decreased peel thickness at harvest (about 8%); however, this difference was not remained during cold storage. Sugar/acid ratio was mainly increased by RDI, but also by RW, due to an important increase in soluble solid content (11% of average value for TW-RDI, RW-C and RW-RDI). In addition, RDI combined with RW, significantly increased the number of fruits in small category 5 at the end of cold storage. Finally, neither ratio yield/TC nor irrigation water productivity were affected by any irrigation treatments.This study was supported by two CICYT (AGL2010-17553 and AGL2013-49047-C2-482 515 2-R) projects and SIRRIMED (KBBE-2009-1- 2-03, PROPOSAL N◦245159) 483 project. We are also grateful to SENECA–Excelencia Científica (19903/GERM/15) for 484 providing funds for this research

Health-related quality of life after angioplasty and stent placement in patients with iliac artery occlusive disease: results of a randomized controlled clinical trial.

BACKGROUND: To assess the quality of life in patients with iliac artery occlusive disease, we compared primary stent placement versus primary angioplasty followed by selective stent placement in a multicenter randomized controlled trial. METHODS AND RESULTS: Quality-of-life assessments were completed by 254 patients in a telephone interview. Assessment measures consisted of the RAND 36-Item Health Survey 1.0, time tradeoff, standard gamble, rating scale, health utilities index, and EuroQol-5D. The interviews were performed before treatment and after 1, 3, 12, and 24 months. When the 2 treatments were compared, no significant difference was observed (P>0.05). All measurements showed a significant improvement in the quality of life after treatment (P<0.05). The RAND 36-Item Health Survey measures physical functioning, role limitations caused by physical problems, and bodily pain and the EuroQol-5D were the most sensitive to the impact of revascularization. CONCLUSIONS: Health-related quality of life improves equally after primary stent placement and primary angioplasty with selective stent placement in the treatment of intermittent claudication caused by iliac artery occlusive disease

NHI 2.1 Veranderingen in NHI

Dit document is een concept en uitsluitend bedoeld voor discussiedoeleinden. Een impuls is gegeven aan het verbeteren van het nationaal hydrologisch instrumentarium, NHI 2.0. NHI 2.0 voldeed in 2010 nog niet volledig aan de wensen van RWS. In 2010 hebben twee processen plaatsgevonden, die tot meer inzicht hebben geleid in de prestaties van het NHI. Ten eerste de regionale toetsing van het NHI, onder andere door STOWA, en ten tweede het gebruik van NHI in diverse regionale en landelijke studies voor Zoetwaterverkenning (ZWV). Als gevolg hiervan zijn in NHI 2.1, in opdracht van de RWS Waterdienst, veel verbeteringen doorgevoerd

Balloon dilation and stent implantation for treatment of femoropopliteal arterial disease: meta-analysis

PURPOSE: To perform a meta-analysis of long-term results of balloon dilation and stent implantation in the treatment of femoropopliteal arterial disease. MATERIALS AND METHODS: The English-language literature was searched for studies published between 1993 and 2000. Inclusion criteria for articles were presentation of long-term primary patency rates, standard errors (explicitly reported or derivable), and baseline characteristics of the study population. Two reviewers independently extracted data, and discrepancies were resolved by consensus. Primary patency rates were combined by using a technique that allows adjustment for differences across study populations. Analyses were adjusted for lesion type and clinical indication. RESULTS: Nineteen studies met the inclusion criteria, representing 923 balloon dilations and 473 stent implantations. Combined 3-year patency rates after balloon dilation were 61% (standard error, 2.2%) for stenoses and claudication, 48% (standard error, 3.3%) for occlusions and claudication, 43% (standard error, 4.1%) for stenoses and critical ischemia, and 30% (standard error, 3.7%) for occlusions and critical ischemia. The 3-year patency rates after stent implantation were 63%-66% (standard error, 4.1%) and were independent of clinical indication and lesion type. Funnel plots demonstrated an asymmetric distribution of the data points associated with stent studies. CONCLUSION: Balloon dilation and stent implantation for claudication and stenosis yield similar long-term patency rates. For more severe femoropopliteal disease, the results of stent implantation seem more favorable. Publication bias could not be ruled out