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Patients with chronic daily headache and overuse of analgesics, triptans, or other acute headache compounds, are considered to suffer from medication-overuse headache (MOH). This implies that medication overuse is the cause of headache chronification. It remains a key question why only two-thirds of patients with chronic migraine-like headache and overuse of pain medication improve after detoxification, whereas the remainder continue to have chronic headache. In the present longitudinal MRI study, we used voxel-based morphometry to investigate gray matter changes related to medication withdrawal in a group of humans with MOH. As a main result, we found that only patients with significant clinical improvement showed a significant decrease of previously increased gray matter in the midbrain including periaqueductal gray matter and nucleus cuneiformis, whereas patients without improvement did not. Patients without treatment response had less gray matter in the orbitofrontal cortex. Another striking result is the correlation of treatment response with the amount of orbitofrontal gray matter. Thus, we demonstrate adaptive gray matter changes within the pain modulatory system in patients with MOH who responded to detoxification, probably reflecting neuronal plasticity. Decreased gray matter in the orbitofrontal cortex at baseline may be predictive of poor response to treatment.

Unbiased genome-wide screens combined with imaging data on brain function may identify novel molecular pathways related to human cognition. Here we performed a dense genome-wide screen to identify episodic memory-related gene variants. A genomic locus encoding the brain-expressed beta-catenin-like protein 1 (CTNNBL1) was significantly (P=7 × 10(-8)) associated with verbal memory performance in a cognitively healthy cohort from Switzerland (n=1073) and was replicated in a second cohort from Serbia (n=524; P=0.003). Gene expression studies showed CTNNBL1 genotype-dependent differences in beta-catenin-like protein 1 mRNA levels in the human cortex. Functional magnetic resonance imaging in 322 subjects detected CTNNBL1 genotype-dependent differences in memory-related brain activations. Converging evidence from independent experiments and different methodological approaches suggests a role for CTNNBL1 in human memory.Molecular Psychiatry advance online publication, 22 November 2011; doi:10.1038/mp.2011.148.

Relational inference denotes the capacity to encode, flexibly retrieve, and integrate multiple memories to combine past experiences to update knowledge and improve decision-making in new situations. Although relational inference is thought to depend on the hippocampus and consciousness, we now show in young, healthy men that it may occur outside consciousness but still recruits the hippocampus. In temporally distinct and unique subliminal episodes, we presented word pairs that either overlapped (“winter–red”, “red–computer”) or not. Effects of unconscious relational inference emerged in reaction times recorded during unconscious encoding and in the outcome of decisions made 1 min later at test, when participants judged the semantic relatedness of two supraliminal words. These words were either episodically related through a common word (“winter–computer” related through “red”) or unrelated. Hippocampal activity increased during the unconscious encoding of overlapping versus nonoverlapping word pairs and during the unconscious retrieval of episodically related versus unrelated words. Furthermore, hippocampal activity during unconscious encoding predicted the outcome of decisions made at test. Hence, unconscious inference may influence decision-making in new situations.

Electromagnetic fields arising from magnetic resonance imaging (MRI) can cause various clinically relevant functional disturbances in patients with cardiac pacemakers. Consequently, an implanted pacemaker is generally considered a contraindication for an MRI scan. With approximately 60 million MRI scans performed worldwide per year, MRI may be indicated for an estimated majority of pacemaker patients during the lifetime of their pacemakers. The availability of MR conditional pacemakers with CE labelling is of particular advantage since they allow the safe use of pacemakers in MRI. In this article the current state of knowledge on pacemakers and MR imaging is discussed. We present the results of a survey conducted among Swiss radiologists to assess current practice in patients with pacemakers.

Background Magnetic resonance imaging (MRI) of pacemaker patients is contraindicated due to documented potential risks to the patient from hazardous interactions between the MRI and pacemaker system. Objective The purpose of this prospective, randomized, controlled, worldwide clinical trial was to evaluate the safety and effectiveness of a pacemaker system designed for safe use in MRI for any bradycardia indicated patient. Methods Patients (n = 464) were randomized to undergo an MRI scan between 9 and 12 weeks postimplant (MRI group, n = 258) or not to undergo MRI (control group, n = 206) after successful implantation of the specially designed dual-chamber pacemaker and leads. Patients were monitored for arrhythmias, symptoms, and pacemaker system function during 14 nonclinically indicated relevant brain and lumbar MRI sequences. Sequences were performed at 1.5 T and included scans with high radiofrequency power deposition and/or high gradient dB/dt exposure. Clinical evaluation of the pacemaker system function occurred immediately before and after MRI, 1 week and 1 month post-MRI, and at corresponding times for the control group. Primary endpoints for safety analyzed the MRI procedure complication-free rate and for effectiveness compared capture and sensing performance between MRI and control groups. Results No MRI-related complications occurred during or after MRI, including sustained ventricular arrhythmias, pacemaker inhibition or output failures, electrical resets, or other pacemaker malfunctions. Pacing capture threshold and sensed electrogram amplitude changes were minimal and similar between study groups. Conclusion This trial documented the ability of this pacemaker system to be exposed in a controlled fashion to MRI in a 1.5 T scanner without adverse impact on patient outcomes or pacemaker system function.

Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, due to safety concerns the presence of an implanted cardiac pacemaker is considered to be a contraindication to MRI in most medical centres. The increasing number of implanted pacemakers and the estimated over 50% probability that a pacemaker patient may be a candidate for an MRI increase the need for safe scanning of pacemaker patients. Over the last ten years a major effort has been made to understand the potential risks. The influences from the three electromagnetic fields on pacemakers are versatile and will be summarised. The research in this area has helped to predict the risks of an MRI scan in patients with conventional pacemakers, and has also stimulated pacemaker manufacturers to improve their devices with the goal of providing MR conditional devices. Since autumn 2008 the first approved MR conditional pacemakers have been on the market and other devices are likely to follow this trend. However, the vast majority of devices are still not approved for MRI, a situation which will take several years to change. It is thus important that a solution be also found for these patients. Several studies including over 500 patients with a pressing need for MRI have been performed at different experienced centres. On the basis of those data various organisations in MRI fields have proposed guidelines for MRI in patients who fulfill given requirements. However, at present, non- MRI modalities should be considered, whenever possible, for diagnosis in pacemaker recipients with conventional devices. If other imaging modalities are not adequate, MRI with careful monitoring and preparation for adverse events may be considered only at experienced centres. With the wider availability of MR conditional devices, the risks of MRI are greatly reduced and non-tertiary centres will be able to perform these investigations. In any case, rapid progress in the field of M

BACKGROUND: Radio Frequency Identification (RFID) devices are becoming more and more essential for patient safety in hospitals. The purpose of this study was to determine patient safety, data reliability and signal loss wearing on skin RFID devices during magnetic resonance imaging (MRI) and computed tomography (CT) scanning. METHODS: Sixty RFID tags of the type I-Code SLI, 13.56 MHz, ISO 18000-3.1 were tested: Thirty type 1, an RFID tag with a 76 x 45 mm aluminum-etched antenna and 30 type 2, a tag with a 31 x 14 mm copper-etched antenna. The signal loss, material movement and heat tests were performed in a 1.5 T and a 3 T MR system. For data integrity, the tags were tested additionally during CT scanning. Standardized function tests were performed with all transponders before and after all imaging studies. RESULTS: There was no memory loss or data alteration in the RFID tags after MRI and CT scanning. Concerning heating (a maximum of 3.6 degrees C) and device movement (below 1 N/kg) no relevant influence was found. Concerning signal loss (artifacts 2 - 4 mm), interpretability of MR images was impaired when superficial structures such as skin, subcutaneous tissues or tendons were assessed. CONCLUSIONS: Patients wearing RFID wristbands are safe in 1.5 T and 3 T MR scanners using normal operation mode for RF-field. The findings are specific to the RFID tags that underwent testing.

Emotionally arousing events are typically well remembered, but there is a large interindividual variability for this phenomenon. We have recently shown that a functional deletion variant of ADRA2B, the gene encoding the alpha2b-adrenergic receptor, is related to enhanced emotional memory in healthy humans and enhanced traumatic memory in war victims. Here, we investigated the neural mechanisms of this effect in healthy participants by using fMRI. Carriers of the ADRA2B deletion variant exhibited increased activation of the amygdala during encoding of photographs with negative emotional valence compared with noncarriers of the deletion. Additionally, functional connectivity between amygdala and insula was significantly stronger in deletion carriers. The present findings indicate that the ADRA2B deletion variant is related to increased responsivity and connectivity of brain regions implicated in emotional memory.

The mechanical property of articular cartilage determines to a great extent the functionality of diarthrodial joints. Consequently, the early detection of mechanical and, thus, functional changes of cartilage is crucial for preventive measures to maintain the mobility and the quality of life of individuals. An alternative to conventional mechanical testing is the inverse finite element approach, enabling non-destructive testing of the tissue. We evaluated a method for the assessment of the equilibrium material properties of the patellar cartilage based on magnetic resonance imaging during patellofemoral compression. We performed ex vivo testing of two equine patellas with healthy cartilage, one with superficial defects, and one with synthetically degenerated cartilage to simulate a pre-osteoarthritic stage. Static compression with 400 N for 2 h resulted in morphological changes comparable to physiological in vivo deformations in humans. We observed a decrease of the equilibrium Young’s modulus of the degenerated cartilage by -59%, which was in the range of the results from indentation (-74%) and confined compression tests (-58%). With the reported accuracy of magnetic resonance imaging and its reproducibility, the results indicate the potential to measure differences in Young’s modulus with regard to cartilage degeneration and consequently to distinguish between healthy and pre-osteoarthritic cartilage.

BACKGROUND: Magnetic Resonance Imaging (MRI) of patients with implanted cardiac devices is currently considered hazardous due to potential for electromagnetic interference to the patient and pacemaker system. With approximately 60 million MRI scans performed worldwide per year, an estimated majority of pacemaker patients may develop an indication for an MRI during the lifetime of their pacemakers, suggesting that safe use of pacemakers in the MRI environment would be clinically valuable. A new pacing system (Medtronic EnRhythm MRItrade mark SureScantrade mark and CapSureFix MRItrade mark leads) has been designed and pre-clinically tested for safe use in the MRI environment. The EnRhythm MRI study is designed to confirm the safety and efficacy of this new pacing system. METHODS: The EnRhythm MRI study is a prospective, randomized controlled, unblinded clinical trial to confirm the safety and efficacy of MRI at 1.5 Tesla in patients implanted with a specifically designed pacemaker and lead system. The patients have standard indications for dual chamber pacemaker implantation. Successfully implanted patients are randomized in a 2:1 ratio to undergo MRI (MRI group) or to have no MRI scan (control group) at 9-12 weeks after pacemaker system implantation. Magnetic resonance (MR) scanning includes 14 head and lumbar scan sequences representing clinically relevant scans while maximizing the gradient slew rate up to 200 T/m/s, and/or the transmitted radiofrequency (RF) power up to SAR (specific absorption rate) levels of 2 W/kg body weight (upper limit of normal operating mode). Full interrogation of all device information and sensing and capture function are measured at device implantation, every follow-up and before and immediately after MRI in the MRI group and at the same time points in the control group. Complete pacemaker and lead evaluations are also done at one week and one month after the scan for the MRI and control group patients.The primary endpoint is safe and s