Hyperpolarized He magnetic resonance imaging: Preliminary evaluation of phenotyping potential in chronic obstructive pulmonary disease

Rationale and objectives

Emphysema and small airway obstruction are the pathological hallmarks of chronic obstructive pulmonary disease (COPD). The aim of this pilot study in a small group of chronic obstructive pulmonary disease (COPD) patients was to quantify hyperpolarized helium-3 (³He) magnetic resonance imaging (MRI) functional and structural measurements and to explore the potential role for ³He MRI in detecting the lung structural and functional COPD phenotypes.

Materials and methods

We evaluated 20 ex-smokers with stage I (n = 1), stage II (n = 9) and stage III COPD (n = 10). All subjects underwent same-day plethysmography, spirometry, ¹H MRI and hyperpolarized ³He MRI at 3.0 T. ³He ventilation defect percent (VDP) was generated from ³He static ventilation images and ¹H thoracic images and the ³He apparent diffusion coefficient (ADC) was derived from diffusion-weighted MRI.

Results

Based on the relative contribution of normalized ADC and VDP, there was evidence of a predominant ³He MRI measurement in seven patients (n = 3 mainly ventilation defects or VDP dominant (VD), n = 4 mainly increased ADC or ADC dominant (AD)). Analysis of variance (ANOVA) showed significantly lower ADC for subjects with predominantly elevated VDP (p = 0.02 compared to subjects with predominantly elevated ADC; p = 0.008 compared to mixed group) and significantly decreased VDP for subjects with predominantly elevated ADC (p = 0.003, compared to mixed group).

Conclusion

In this small pilot study, a preliminary analysis shows the potential for ³He MRI to categorize or phenotype COPD ex-smokers, providing good evidence of feasibility for larger prospective studies.     

Is it safe to perform coronary angiography during acute endocarditis?

A best evidence topic was written according to a structured protocol. The question addressed was 'Is it safe to perform coronary angiography (CA) in acute endocarditis?' Three hundred and ninety-seven papers were found using the reported search, of which six represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes, key results and limitations of these papers are tabulated. One of the papers is a case report, which reported a fatal vegetation embolism from an infected aortic valve into the left main coronary artery 14 h after angiography. The remaining five papers are cohort studies. Four of these studies were performed between 1970 and 1980 before the era of echocardiography and were aimed at quantifying the severity of valvular regurgitation. No embolic complications or dislodgement of vegetations occurred in any of the five studies (186 patients). Guidelines published by the European Society of Cardiology (ESC) in 2009 recommended CA in the context of infective endocarditis (IE) for men >40 years old, postmenopausal women, and patients with at least one cardiovascular risk factor or a history of coronary artery disease. Exceptions include patients with large aortic vegetations which may be dislodged during catheterisation, and when emergency surgery is necessary - 1) native aortic or mitral IE with severe acute regurgitation or valve obstruction, or prosthetic valve IE with severe prosthetic dysfunction (dehiscence or obstruction) causing refractory pulmonary oedema or cardiogenic shock; 2) native aortic, mitral, or prosthetic valve IE with fistula into a cardiac chamber or pericardium causing refractory pulmonary oedema or shock. This is reiterated by the guidelines on the management of valvular heart disease published by the ESC in 2007. From the findings of the six papers, it can be concluded that coronary angiography can be performed safely in IE and should be performed if deemed necessary, unless the patients are haemodynamically unstable requiring emergency surgery, or have large vegetations of the aortic valve. This is consistent with the ESC guidelines.     

Assessing the impact of user-centered research on a clinical trial eHealth tool via counterbalanced research design

Objective

Informatics applications have the potential to improve participation in clinical trials, but their design must be based on user-centered research. This research used a fully counterbalanced experimental design to investigate the effect of changes made to the original version of a website, http://BreastCancerTrials.org/, and confirm that the revised version addressed and reinforced patients'' needs and expectations.

Design

Participants included women who had received a breast cancer diagnosis within the last 5 years (N=77). They were randomized into two groups: one group used and reviewed the original version first followed by the redesigned version, and the other group used and reviewed them in reverse order.

Measurements

The study used both quantitative and qualitative measures. During use, participants'' click paths and general reactions were observed. After use, participants were asked to answer survey items and open-ended questions to indicate their reactions and which version they preferred and met their needs and expectations better.

Results

Overall, the revised version of the site was preferred and perceived to be clearer, easier to navigate, more trustworthy and credible, and more private and safe overall. However, users who viewed the original version last had similar attitudes toward both versions.

Conclusion

By applying research findings to the redesign of a website for clinical trial searching, it was possible to re-engineer the interface to better support patients'' decisions to participate in clinical trials. The mechanisms of action in this case appeared to revolve around creating an environment that supported a sense of personal control and decisional autonomy.