I n North America most clinical MRI is performed at 1.5 T or 3.0 T, and some research applications have moved to 7.0 T. High field is motivated by higher polarization, promising increased signal-to-noise ratio (SNR), and resolution. However, this causes image distortion, constrained imaging efficiency, increased specific absorption rate, and higher cost. For some applications, low field strength may offer intrinsic advantages (1,2). At low field strength, short T1 and long T2* allow more efficient pulse sequence design; imaging near air-tissue interfaces is improved by virtue of reduced susceptibility gradients; and specific absorption rate is reduced, which can diminish heating of conductive devices and implants, and can eliminate pulse sequence parameter constraints (3). Commercial lower field systems have been largely overlooked as hardware and software have improved over the last 2 decades, and therefore are not well-suited for technically demanding imaging. We developed and evaluated a custom 0.55-T MRI system equipped with contemporary

BackgroundClinical treatment of cardiac arrhythmia by radiofrequency ablation (RFA) currently lacks quantitative and precise visualization of lesion formation in the myocardium during the procedure. This study aims at evaluating thermal dose (TD) imaging obtained from real-time magnetic resonance (MR) thermometry on the heart as a relevant indicator of the thermal lesion extent.MethodsMR temperature mapping based on the Proton Resonance Frequency Shift (PRFS) method was performed at 1.5 T on the heart, with 4 to 5 slices acquired per heartbeat. Respiratory motion was compensated using navigator-based slice tracking. Residual in-plane motion and related magnetic susceptibility artifacts were corrected online. The standard deviation of temperature was measured on healthy volunteers (N = 5) in both ventricles. On animals, the MR-compatible catheter was positioned and visualized in the left ventricle (LV) using a bSSFP pulse sequence with active catheter tracking. Twelve MR-guided RFA were performed on three sheep in vivo at various locations in left ventricle (LV). The dimensions of the thermal lesions measured on thermal dose images, on 3D T1-weighted (T1-w) images acquired immediately after the ablation and at gross pathology were correlated.ResultsMR thermometry uncertainty was 1.5 °C on average over more than 96% of the pixels covering the left and right ventricles, on each volunteer. On animals, catheter repositioning in the LV with active slice tracking was successfully performed and each ablation could be monitored in real-time by MR thermometry and thermal dosimetry. Thermal lesion dimensions on TD maps were found to be highly correlated with those observed on post-ablation T1-w images (R = 0.87) that also correlated (R = 0.89) with measurements at gross pathology.ConclusionsQuantitative TD mapping from real-time rapid CMR thermometry during catheter-based RFA is feasible. It provides a direct assessment of the lesion extent in the myocardium with precision in the range of one millimeter. Real-time MR thermometry and thermal dosimetry may improve safety and efficacy of the RFA procedure by offering a reliable indicator of therapy outcome during the procedure.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-017-0323-0) contains supplementary material, which is available to authorized users.

Homeopathic proving symptoms appear to be specific to the medicine and do not seem to be due to a local process. Since this was a pilot study using a small number of provers, rival hypotheses cannot be ruled out and the study needs replication.

The objective of this study is to determine the impact of expectation associated with placebo and caffeine ingestion. We used a three-armed, randomized, double-blind design. Two three-armed experiments varying instruction (true, false, control) investigated the role of expectations of changes in arousal (blood pressure, heart rate), subjective well-being, and reaction time (RT). In Experiment 1 (N = 45), decaffeinated coffee was administered, and expectations were produced in one group by making them believe they had ingested caffeinated coffee. In Experiment 2 (N = 45), caffeinated orange juice was given in both experimental groups, but only one was informed about the true content. In Experiment 1, a significant effect for subjective alertness was found in the placebo treatment compared to the control group. However, for RT and well-being no significant effects were found. In Experiment 2, no significant expectancy effects were found. Caffeine produced large effects for blood pressure in both treatments compared to the control group, but the effects were larger for the false information group. For subjective well-being (alertness, calmness), considerable but nonsignificant changes were found for correctly informed participants, indicating possible additivity of pharmacologic effect and expectations. The results tentatively indicate that placebo and expectancy effects primarily show through introspection.

Findings in parapsychology suggest an effect of distant intentionality. Two laboratory set-ups explored this topic by measuring the effect of a distant intention on psychophysiological variables. The 'Direct Mental Interaction in Living Systems' experiment investigates the effect of various intentions on the electrodermal activity of a remote subject. The 'Remote Staring' experiment examines whether gazing by an observer covaries with the electrodermal activity of the person being observed. Two meta-analyses were conducted. A small significant effect size (d =.11, p =.001) was found in 36 studies on 'direct mental interaction', while a best-evidence-synthesis of 7 studies yielded d =.05 (p =.50). In 15 remote staring studies a mean effect size of d = 0.13 (p =.01) was obtained. It is concluded that there are hints of an effect, but also a shortage of independent replications and theoretical concepts.

AimsMagnetic resonance imaging (MRI) is the gold standard for defining myocardial substrate in 3D and can be used to guide ventricular tachycardia ablation. We describe the feasibility of using a prototype magnetic resonance-guided electrophysiology (MR-EP) system in a pre-clinical model to perform real-time MRI-guided epicardial mapping, ablation, and lesion imaging with active catheter tracking.Methods and resultsExperiments were performed in vivo in pigs (n = 6) using an MR-EP guidance system research prototype (Siemens Healthcare) with an irrigated ablation catheter (Vision-MR, Imricor) and a dedicated electrophysiology recording system (Advantage-MR, Imricor). Following epicardial access, local activation and voltage maps were acquired, and targeted radiofrequency (RF) ablation lesions were delivered. Ablation lesions were visualized in real time during RF delivery using MR-thermometry and dosimetry. Hyper-acute and acute assessment of ablation lesions was also performed using native T1 mapping and late-gadolinium enhancement (LGE), respectively. High-quality epicardial bipolar electrograms were recorded with a signal-to-noise ratio of greater than 10:1 for a signal of 1.5 mV. During epicardial ablation, localized temperature elevation could be visualized with a maximum temperature rise of 35 °C within 2 mm of the catheter tip relative to remote myocardium. Decreased native T1 times were observed (882 ± 107 ms) in the lesion core 3–5 min after lesion delivery and relative location of lesions matched well to LGE. There was a good correlation between ablation lesion site on the iCMR platform and autopsy.ConclusionThe MR-EP system was able to successfully acquire epicardial voltage and activation maps in swine, deliver, and visualize ablation lesions, demonstrating feasibility for intraprocedural guidance and real-time assessment of ablation injury.

Objective According to a series of recent meta‐analyses and systematic reviews, aromatherapy has shown to be effective in treating patients with different medical conditions. However, many of the clinical studies are of rather low methodological quality. Moreover, there is much conceptual ambiguity with regard to what aromatherapy actually constitutes. Method In this paper, we discuss the conditions under which aromatherapy is most likely to be of medical value by outlining the workings of the olfactory system and the necessary requirements of odors to be therapeutic. We then introduce an aromatherapeutic inhaler that was tested in a series of studies involving 465 participants. Results This inhaler (AromaStick®) produced large to very large effects across a variety of physiological target systems (e.g., cardiovascular, endocrine, blood oxygenation, and pain), both short term and long term. Discussion Inhalation of volatile compounds from essential oils yields almost immediate, large, and clinically relevant effects as long as the scents are delivered highly concentrated from an appropriate device. The changes caused in the body seem side effect‐free and can be sustained when inhalation is repeated.

We conducted two parallel, blinded homeopathic pathogenetic trials conducted at two different sites to determine whether symptoms reported by healthy volunteers were significantly different for homeopathic remedies than for placebos. Study 1 used a two-armed design, testing ozone against placebo. Study 2 used a three-armed design, testing ozone and iridium against placebo. We found significantly more remedy-specific symptoms in provers taking ozone or iridium than in provers taking placebo in the three-armed trial and in both trials pooled for ozone and placebo. We, therefore, conclude that homeopathic remedies produce more symptoms typical for a remedy than non-typical symptoms. The results furthermore suggest a somewhat non-classical pattern because symptoms of one remedy appear to be mimicked in the other trial arm. This might be indicative of entanglement in homeopathic systems.