Image technique optimization in MR imaging of a titanium alloy joint prosthesis

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at 1.0 T. The SE imaging parameters were bandwidth/pixel (BW/p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256–512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.     

Deficiencies in the transfer and availability of clinical trials evidence: a review of existing systems and standards

ABSTRACT: BACKGROUND: Decisions concerning drug safety and efficacy are generally based on pivotal evidence provided by clinical trials. Unfortunately, finding the relevant clinical trials is difficult and their results are only available in text-based reports. Systematic reviews aim to provide a comprehensive overview of the evidence in a specific area, but may not provide the data required for decision making. METHODS: We review and analyze the existing information systems and standards for aggregate level clinical trials information from the perspective of systematic review and evidence-based decision making. RESULTS: The technology currently used has major shortcomings, which cause deficiencies in the transfer, traceability and availability of clinical trials information. Specifically, data available to decision makers is insufficiently structured, and consequently the decisions cannot be properly traced back to the underlying evidence. Regulatory submission, trial publication, trial registration, and systematic review produce unstructured datasets that are insufficient for supporting evidence-based decision making. CONCLUSIONS: The current situation is a hindrance to policy decision makers as it prevents fully transparent decision making and the development of more advanced decision support systems. Addressing the identified deficiencies would enable more efficient, informed, and transparent evidence-based medical decision making.     

Influence of physical activity on vertebral strength during late adolescence

Background contextReduced vertebral strength is a clear risk factor for vertebral fractures. Men and women with vertebral fractures often have reduced vertebral size and bone mineral density (BMD). Vertebral strength is controlled by both genetic and developmental factors. Malnutrition and low levels of physical activity are commonly considered to result in reduced bone size during growth. Several studies have also demonstrated the general relationship between BMD and physical activity in the appendicular skeleton.PurposeIn this study, we wanted to clarify the role of physical activity on vertebral bodies. Vertebral dimensions appear to generally be less pliant than long bones when lifetime changes occur. We wanted to explore the association between physical activity during late adolescence and vertebral strength parameters such as cross-sectional size and BMD.Study designThe association between physical activity and vertebral strength was explored by measuring vertebral strength parameters and defining the level of physical activity during adolescence.Patient sampleThe study population consisted of 6,928 males and females who, at 15 to 16 and 19 years of age, responded to a mailed questionnaire inquiring about their physical activity. A total of 558 individuals at the mean age of 21 years underwent magnetic resonance imaging (MRI) scans.MethodsWe measured the dimensions of the fourth lumbar vertebra from the MRI scans of the Northern Finland Birth Cohort 1986 and performed T2* relaxation time mapping, reflective of BMD. Vertebral strength was based on these two parameters. We analyzed the association of physical activity on vertebral strength using the analysis of variance.Results and conclusionsWe observed no association between the level of physical activity during late adolescence and vertebral strength at 21 years.     

Body mass index and health-related quality of life in apparently healthy individuals

Purpose

Obesity is known to be associated with a range of chronic medical comorbidities, but little is known about the impact of overweight and obesity on health-related quality of life (HRQoL) in persons without chronic diseases. The aim of this study was to assess HRQoL, body mass index (BMI) and health behavior patterns in a community sample of subjects who had no long-lasting medical comorbidities

Methods

We assessed HRQoL in 1,187 apparently healthy individuals (mean age 57 ± 7 years), of whom 24 % were classified as normal weight, 49 % as overweight, 20 % as obese and 7 % as very obese. Two different instruments of HRQoL were used: the generic Short-Form Health Survey (SF-36) questionnaire and the preference-based instrument EuroQol (EQ-5D).

Results

All physical components of the SF-36 decreased linearly according to BMI categories in women. In men, only poorer physical functioning scale showed linearity with rising BMI. Scores on the mental components of the SF-36 did not differ by BMI categories in either gender. The EQ-5D index and EuroQol visual analogue scale scores decreased linearly with rising BMI only in women.

Conclusions

In apparently healthy middle-aged subjects, physical HRQoL decreases with increasing level of BMI and more so in women than in men. Mental components of HRQoL do not differ between the categories of BMI in either gender.