Who lives in care homes in Greenland? A nationwide survey of demographics, functional level, medication use and comorbidities.

BACKGROUND: Greenland is facing an ageing population, and little is known about the characteristics of the elderly population in Greenland. This study offers both a comparison and a description of the demographics, causes of admission, comorbidities and medication of the residents in care homes in the capital, major and minor towns in four of the five administrative regions of Greenland. METHODS: The study was conducted from 2010 to 2016 as a descriptive questionnaire-based cross-sectional study. Data from eligible residents from eight care homes were collected from the regular care staff. Data were categorised into three groups based on town size for analysis. RESULTS: 244 (100 %) of eligible residents participated in the study. Nearly 100 % were of Greenlandic ethnicity based on parents' place of birth, and 62 % were women. The median age at admission/study was 69/71 years for men and 77/79 years for women (both p = 0.001). The median Body Mass Index was 25.6 kg/m2, more than half of the population were previous- or never-smokers and less than ten per cent consumed more than ten drinks of alcohol per week. The most common causes of admission were dementia (25.4 %), stroke (19.3 %) and social causes (11.1 %), while stroke (30.7 %), dementia (29.5 %) and musculoskeletal diseases (25.8 %) were the most common diagnoses at the time of the study. The Barthel Index was used to estimate the residents' level of independence, and residents in smaller towns were found to have a higher level of independence than residents in the capital. The median number of prescribed medications was five, and more residents in the capital were prescribed more than ten medications than elsewhere in Greenland. CONCLUSIONS: This study is the first to describe care home residents in Greenland. We found a population younger than residents in comparable Danish care homes and that women were older than men at admission. In addition, care home residents in the capital had a lower level of independence and a higher number of prescribed medications, which could relate to differences in morbidity, access to health care services and differences in social circumstances influencing the threshold for care home admission.

High-throughput screening of multifunctional nanocoatings based on combinations of polyphenols and catecholamines.

Biomimetic surface coatings based on plant polyphenols and catecholamines have been used broadly in a variety of applications. However, the lack of a rational cost-effective platform for screening these coatings and their properties limits the true potential of these functional materials to be unleashed. Here, we investigated the oxidation behavior and coating formation ability of a library consisting of 45 phenolic compounds and catecholamines. UV-vis spectroscopy demonstrated significant acceleration of oxidation and polymerization under UV irradiation. We discovered that several binary mixtures resulted in non-additive behavior (synergistic or antagonistic effect) yielding much thicker or thinner coatings than individual compounds measured by ellipsometry. To investigate the properties of coatings derived from new combinations, we used a miniaturized high-throughput strategy to screen 2,532 spots coated with single, binary, and ternary combinations of coating precursors in one run. We evaluated the use of machine learning models to learn the relation between the chemical structure of the precursors and the thickness of the nanocoatings. Formation and stability of nanocoatings were investigated in a high-throughput manner via discontinuous dewetting. 30 stable combinations (hits) were used to tune the surface wettability and to form water droplet microarray and spot size gradients of water droplets on the coated surface. No toxicity was observed against eukaryotic HeLa cells and Pseudomonas aeruginosa (strain PA30) bacteria after 24 h incubation at 37 °C. The strategy introduced here for high-throughput screening of nanocoatings derived from combinations of coating precursors enables the discovery of new functional materials for various applications in science and technology in a cost-effective miniaturized manner.

Radiological and pathological evaluation of the level of arterial division after colon cancer surgery.

AIM: In aiming to cure patients with colorectal cancer surgery, the surgeon must carefully dissect the mesocolon and mesorectum and divide the vascular pedicle near to its origin so as to include all local lymph nodes. This has been termed complete mesocolic excision. The distance from the distal vascular tie to the bowel wall in the fixed specimen is an indication as to the quality of surgery but this does not assess the length of the residual vascular pedicle and, by implication, residual lymph nodes. The aim of this study was to establish if our surgeons were carrying out complete mesocolic excision by assessing the length of the proximal arterial pedicle and relating this to arterial length in the fixed specimen. METHOD: This was a single centre prospective study of patients undergoing elective surgery for locally advanced colorectal cancer. An abdominal and pelvic CT scan was performed 2 days postoperatively and a radiologist blinded to the operative procedure measured the length of the residual arterial stump. Similarly, the length of the vessel in the fixed resected specimen and lymph node yield were also recorded. RESULTS: Fifty-two patients were recruited. The mean length of the residual arterial stump was 38 mm (95% CI: 33-43), which was significantly longer than the < 10 mm recommended in guidelines (P < 0.0001). The mean length was 31 mm (95% CI: 25-37) and 49 mm (95% CI: 40-57) for left and right sided resections respectively. There was no correlation between the residual arterial stump and the pathology. CONCLUSIONS: The residual arterial length was greater than suggested by guidelines and may indicate that our surgery is less radical than we planned. Caution should be taken when using pathological measurements of vascular ligation as it may not reflect the height of the pedicle division.

Experimental pain impairs recognition memory irrespective of pain predictability.

BACKGROUND: Pain is hardwired to signal threat and tissue damage and therefore automatically attracts attention to initiate withdrawal or defensive behaviour. This well-known interruptive function of pain interferes with cognitive functioning and is modulated by bottom-up and top-down variables. Here, we applied predictable or unpredictable painful heat stimuli simultaneously to the presentation of neutral images to investigate (I) whether the predictability of pain modulated its effect on the encoding of images (episodic memory) and (II) whether subjects remember that certain images have been previously presented with pain (source memory). METHODS: Twenty-four healthy subjects performed a categorization task in which 80 images had to be categorized into living or non-living objects. We compared the processing and encoding of these images during cued and non-cued pain trials as well as cued and non-cued pain-free trials. Effects on recognition performance and source memory for pain were immediately tested using a surprise recognition task. RESULTS: Painful thermal stimulation impaired recognition accuracy (d', recollection, familiarity). This negative effect of pain was positively correlated with the individual expectation of pain interference and the attentional avoidance of pain-related words. However, the interruptive effect of pain was not modulated by the predictability of pain. Source memory for painful stimulation was at chance level, indicating that subjects did not explicitly remember that images had been paired with pain. CONCLUSIONS: Targeting negative expectations and a maladaptive attentional bias for pain-related material might help reducing frequently reported pain-induced cognitive impairments.

German Roentgen Society Statement on MR Imaging of Patients with Cardiac Pacemakers.

UNLABELLED: The aim of this paper is to inform physicians, especially radiologists and cardiologists, about the technical and electrophysiological background of MR imaging of patients with implanted cardiac pacemakers (PM) and to provide dedicated clinical practice guidelines how to perform MR exams in this patient group. The presence of a conventional PM system is not any more considered an absolute contraindication for MR imaging. The prerequisites for MR imaging on pacemaker patients include the assessment of the individual risk/benefit ratio as well as to obtain full informed consent about the off label character of the procedure and all associated risks. Furthermore the use of special PM-related (e.g. re-programming of the PM) and MRI-related (e.g. limitation of whole body SAR to 2 W/kg) precautions is required and needs to be combined with adequate monitoring during MR imaging using continuous pulsoximetry. MR conditional PM devices are tested and approved for the use in the MR environment under certain conditions, including the field strength and gradient slew rate of the MR system, the maximum whole body SAR value and the presence of MR imaging exclusion zones. Safe MR imaging of patients with MR conditional PM requires the knowledge of the specific conditions of each PM system. If MR imaging within these specific conditions cannot be guaranteed in a given patient, the procedure guidelines for conventional PM should be used. The complexity of MR imaging of PM patients requires close cooperation of radiologists and cardiologists. KEY POINTS: Conventional pacemaker systems are no longer an absolute but rather a relative contraindication for performing an MR examination. The procedural management of conventional pacemaker includes the assessment of the individual risk/benefit ratio, comprehensive patient informed consent about specific related risks and "off label" use, extensive PM- and MRI-related safety precautions as well as adequate monitoring techniques during the MR exam. Decisive for patient safety are precise understanding of, and compliance with, the terms of use for the specific MR-conditional pacemaker system. If the electrophysiological and MRI-specific conditions for use of MR-conditional pacemakers are not met or compliance with these conditions for use cannot be guaranteed, the device must be treated like a conventional pacemaker.

Structure-function-behavior relationship in estrogen-induced synaptic plasticity.

This article is part of a Special Issue "Estradiol and Cognition". In estrogen-induced synaptic plasticity, a correlation of structure, function and behavior in the hippocampus has been widely established. 17ß-estradiol has been shown to increase dendritic spine density on hippocampal neurons and is accompanied by enhanced long-term potentiation and improved performance of animals in hippocampus-dependent memory tests. After inhibition of aromatase, the final enzyme of estradiol synthesis, with letrozole we consistently found a strong and significant impairment of long-term potentiation (LTP) in female mice as early as after six hours of treatment. LTP impairment was followed by loss of hippocampal spine synapses in the hippocampal CA1 area. Interestingly, these effects were not found in male animals. In the Morris water maze test, chronic administration of letrozole did not alter spatial learning and memory in either female or male mice. In humans, analogous effects of estradiol on hippocampal morphology and physiology were observed using neuroimaging techniques. However, similar to our findings in mice, an effect of estradiol on memory performance has not been consistently observed.

Randomized controlled trial comparing Moviprep® and Phosphoral® as bowel cleansing agents in patients undergoing colonoscopy.

BACKGROUND: Introducing colonoscopy as part of colorectal cancer screening on a national level, we aimed at evaluating the efficacy of the two most common bowel cleansing agents, Moviprep(®) and Phosphoral(®). Secondly, we evaluated the benefit for the patient and society in terms of sick leave and discomfort. METHODS: In a single-blinded randomized equivalence trial, Phosphoral(®) (NaP) was compared with Moviprep(®) (2 l polyethylene glycol + ascorbic acid) in patients undergoing colonoscopy due to suspicion of cancer. Patients filled out questionnaires concerning stool consistency, discomfort and number of sick days due to bowel cleansing. Blinded colonoscopists estimated the efficiency of the cleansing using the validated Harefield Cleansing Scale. RESULTS: Two hundred and sixty-six patients were included 250 of whom underwent full colonoscopy. There was no difference in the percentage of acceptable bowel cleansings in the two groups; however, a significantly higher number of A scores were observed in the Moviprep(®) group (p = 0.028). We found no correlation between stool consistency and outcome of the cleansing and no difference in subjective discomfort during cleansing. Vomiting during cleansing occurred more often in the Phosphoral(®) group (p = 0.002). There was a trend toward a smaller number of sick days in patients who used Moviprep(®) compared with Phosphoral(®). CONCLUSIONS: Moviprep(®) and Phosphoral(®) provided equally efficient bowel cleansing in 90 % of patients, but Moviprep(®) provided a higher quality of cleansings graded as successful. The two agents were equally tolerated, and no difference was found in the related number of sick days.

Neural systems for choice and valuation with counterfactual learning signals.

The purpose of this experiment was to test a computational model of reinforcement learning with and without fictive prediction error (FPE) signals to investigate how counterfactual consequences contribute to acquired representations of action-specific expected value, and to determine the functional neuroanatomy and neuromodulator systems that are involved. 80 male participants underwent dietary depletion of either tryptophan or tyrosine/phenylalanine to manipulate serotonin (5HT) and dopamine (DA), respectively. They completed 80 rounds (240 trials) of a strategic sequential investment task that required accepting interim losses in order to access a lucrative state and maximize long-term gains, while being scanned. We extended the standard Q-learning model by incorporating both counterfactual gains and losses into separate error signals. The FPE model explained the participants' data significantly better than a model that did not include counterfactual learning signals. Expected value from the FPE model was significantly correlated with BOLD signal change in the ventromedial prefrontal cortex (vmPFC) and posterior orbitofrontal cortex (OFC), whereas expected value from the standard model did not predict changes in neural activity. The depletion procedure revealed significantly different neural responses to expected value in the vmPFC, caudate, and dopaminergic midbrain in the vicinity of the substantia nigra (SN). Differences in neural activity were not evident in the standard Q-learning computational model. These findings demonstrate that FPE signals are an important component of valuation for decision making, and that the neural representation of expected value incorporates cortical and subcortical structures via interactions among serotonergic and dopaminergic modulator systems.

DynaMesh® in the repair of laparoscopic ventral hernia: a prospective trial.

PURPOSE: To investigate mesh-related complications in patients undergoing laparoscopic ventral hernia repair using DynaMesh®. METHODS: In the period 1 January 2005 through 31 December 2010, 181 consecutive patients undergoing laparoscopic ventral hernia repair in our day surgery unit using DynaMesh® were entered prospectively in the National Danish Hernia Database. Data concerning abdominal reoperations after hernia repair were later collected on all 181 patients from the National Danish Health Registry. Postoperative telephone interviews were conducted estimating postoperative pain and patient satisfaction. RESULTS: Six % (11 patients) were reoperated because of mesh-related complications. Three had small bowel obstruction and one had a colonic fistula with mesh infection, all causing bowel resection and mesh removal. Mesh-related cutaneous fistula was seen in one patient. Six patients had a symptomatic recurrence requiring reoperation. Abdominal wall hematomas were seen in two cases, while two other patients had symptomatic large seromas, of which one was drained surgically. After a median follow-up of 34 months (range 12-63) in 140 patients, 66 % were pain free (0 on the Numeric Rating Scale (NRS)). Of 26 patients with moderate to severe pain (NRS > 3) at follow-up, only 4 regretted the operation. Sixteen patients thought they had a recurrence, of these only 3 regretted the operation. CONCLUSION: The use of DynaMesh® in laparoscopic ventral hernia repair was associated with a 6 % risk of mesh-related reoperation in a high volume setting. Despite chronic pain in 19 %, after 34 months follow-up patient satisfaction was high.

Perioperative music may reduce pain and fatigue in patients undergoing laparoscopic cholecystectomy.

BACKGROUND: Acute post-operative pain is a predictor in the development of chronic pain after laparoscopic cholecystectomy. Music has been shown to reduce surgical stress. In a randomized, clinical trial, we wanted to test the hypothesis that perioperative and post-operative soft music reduces pain, nausea, fatigue and surgical stress in patients undergoing laparoscopic cholecystectomy as day surgery. METHOD: The study was performed in otherwise healthy Danish patients eligible for day surgery. Ninety-three patients were included and randomized to either soft music or no music perioperatively and post-operatively. Using visual analog score pain, nausea and fatigue at baseline, 1 h, 3 h, 1 day and 7 days after surgery were recorded. C-reactive protein and cortisol were sampled before and after surgery. RESULTS: Music did not lower pain 3 h after surgery, which was the main outcome. The music group had less pain day 7 (P = 0.014). Nausea was low in both groups and was not affected by music. The music group experienced less fatigue at day 1 (P = 0.042) and day 7 (P = 0.015). Cortisol levels decreased during surgery in the music group (428.5-348.0 nmol/l), while it increased in the non-music group (443.5-512.0 nmol/l); still, the difference between the two groups were only significant using general linear models as post-hoc analysis. Soft music did not affect C-reactive protein levels. CONCLUSION: Soft music did not reduce pain 3 h after laparoscopic cholecystectomy. Soft music may reduce later post-operative pain and fatigue by decreasing the surgical stress response.

Randomized clinical trial of self-gripping mesh versus sutured mesh for Lichtenstein hernia repair.

BACKGROUND: Many patients develop discomfort after open repair of a groin hernia. It was hypothesized that suture fixation of the mesh is a cause of these symptoms. METHODS: This patient- and assessor-blinded randomized multicentre clinical trial compared a self-gripping mesh (Parietene Progrip(®)) and sutured mesh for open primary repair of uncomplicated inguinal hernia by the Lichtenstein technique. Patients were assessed before surgery, on the day of operation, and at 1 and 12 months after surgery. The primary endpoint was moderate or severe symptoms after 12 months, including a combination of chronic pain, numbness and discomfort. RESULTS: The intention-to-treat population comprised 163 patients with self-gripping mesh and 171 with sutured mesh. The 12-month prevalence of moderate or severe symptoms was 17·4 and 20·2 per cent respectively (P = 0·573). There were no significant differences between the groups in postoperative complications (33·7 versus 40·4 per cent; P = 0·215), rate of recurrent hernia within 1 year (1·2 per cent in both groups) or quality of life. CONCLUSION: The avoidance of suture fixation using a self-gripping mesh was not accompanied by a reduction in chronic symptoms after inguinal hernia repair. REGISTRATION NUMBER: NCT00815698 (http://www.clinicaltrials.gov).

Dobutamine stress tagging and gradient-echo imaging for detection of coronary heart disease at 3 T.

OBJECTIVE: The purpose of this study was to evaluate the feasibility and diagnostic accuracy of a combined spoiled gradient-echo (sGRE) and tagged gradient-echo (SPAMM-GRE) protocol for detection of coronary artery disease (CAD) during high-dose dobutamine stress at 3 T. METHOD: The study protocol was approved by the local ethics committee. For stress testing, a standard high-dose dobutamine protocol was employed. Image quality at the highest stress level and diagnostic accuracy of the sGRE and SPAMM-GRE sequences were compared. The final study population consisted of 37 patients. RESULTS: The mean image quality score was 2.6±0.6 for the sGRE sequence and 2.4±0.6 for the SPAMM-GRE sequence (p>0.05). Sensitivity, specificity and diagnostic accuracy were 0.81, 0.86, 0.84 and 0.88, 0.86, 0.86 for the sGRE and SPAMM-GRE, respectively. In three cases with new wall motion abnormalities (WMAs), detected by sGRE and SPAMM-GRE, WMAs were detected at a lower stress level by tagging. CONCLUSION: The combined sGRE and SPAMM-GRE high-dose dobutamine protocol at 3 T is feasible and delivers good diagnostic accuracy. Tagging increases the sensitivity of high-dose dobutamine stress testing for detection of CAD and may allow for detection of new WMAs at lower stress levels compared with sGRE alone.

Laparoscopic repair of perforated ulcer in Western Denmark - a retrospective study.

OBJECTIVE: to report the distribution and results of laparoscopic repair of perforated ulcer surgery in surgical departments in a major region in Denmark and compare it with the results from the national database regarding mortality and morbidity. METHOD: case charts from all patients who underwent laparoscopic repair of perforated ulcer in Western Denmark in the period 1 January 2003 - 1 July 2007 were collected. Demographical data, surgical details, morbidity, 30-day mortality, and length of stay were recorded. For comparison, data from the National Health Registry (NIP) describing all patients who had an operation due to perforated ulcer in this period was obtained. RESULTS: no more than 51 out of 818 patients undergoing operation for perforated ulcer in the region had a laparoscopic operation. Mortality in the laparoscopic group was 4% compared to 26% reported from the national database (NIP). The laparoscopic group had a higher reperforation rate but length of stay was equal. No formal criteria concerning surgeon or patients selection for laparoscopic surgery were met. CONCLUSION: laparoscopic repair of perforated ulcer was done without any selection criteria in few surgical departments in Western Denmark and was associated with a low mortality but a higher risk of reperforation.

From the genome to the phenome and back: linking genes with human brain function and structure using genetically informed neuroimaging.

In recent years, an array of brain mapping techniques has been successfully employed to link individual differences in circuit function or structure in the living human brain with individual variations in the human genome. Several proof-of-principle studies provided converging evidence that brain imaging can establish important links between genes and behaviour. The overarching goal is to use genetically informed brain imaging to pinpoint neurobiological mechanisms that contribute to behavioural intermediate phenotypes or disease states. This special issue on "Linking Genes to Brain Function in Health and Disease" provides an overview over how the "imaging genetics" approach is currently applied in the various fields of systems neuroscience to reveal the genetic underpinnings of complex behaviours and brain diseases. While the rapidly emerging field of imaging genetics holds great promise, the integration of genetic and neuroimaging data also poses major methodological and conceptual challenges. Therefore, this special issue also focuses on how these challenges can be met to fully exploit the synergism of genetically informed brain imaging.

Precision of cephalometric analysis via fully and semiautomatic evaluation of digital lateral cephalographs.

OBJECTIVES: The aim of this study was to evaluate the precision of the cephalometric analysis using the orthodontic software Orthometric((R)) in two modes: fully automatic without any help by the user and semiautomatic with manual determination of all cephalometric landmarks. METHODS: From 100 indirectly digitally produced cephalographs, 72 were chosen randomly. On each one of these, three methods were applied on 12 decision-relevant cephalometric angles according to Hasund/Segner: (1) hand drawing on a transparent sheet over the cephalographic film; (2) software semiautomatically with manual correction on the screen; and (3) fully automatically. The hand-based method (1) is well established as a quality standard and reference. The angle measurement results of this method were compared with those of the semiautomatic and the fully automatic method by calculation of the mean absolute differences. Additionally, five randomly chosen cephalographs were evaluated ten times using all three methods for statistical evaluation of reproducibility. RESULTS: At tenfold evaluation of five cephalographs, the standard deviations of the angles were between 0.05 degrees and 0.8 degrees . These results were similar using all three methods. All three methods had similar reproducibility. At evaluation of 72 cephalographs, the mean absolute angle differences between the hand-based (1) and semiautomatic (2) methods were below 2 degrees and so within the allowed tolerance limit, except for the nasolabial angle. In contrast to this, all mean absolute angle differences between the (1) hand-based and (3) fully automatic methods exceeded 2 degrees , and with this the tolerance limit allowed by literature. CONCLUSIONS: The fully automatic determination of the cephalometric landmarks has led to relevant errors up to now, so that it is mandatory to check all automatically set landmarks and to correct them if required. In the case of the semiautomatic method, all relevant angles can be determined with the same reliability as hand drawing.

Distinct muscle imaging patterns in myofibrillar myopathies.

OBJECTIVE: To compare muscle imaging findings in different subtypes of myofibrillar myopathies (MFM) in order to identify characteristic patterns of muscle alterations that may be helpful to separate these genetic heterogeneous muscular disorders. METHODS: Muscle imaging and clinical findings of 46 patients with MFM were evaluated (19 desminopathy, 12 myotilinopathy, 11 filaminopathy, 1 alphaB-crystallinopathy, and 3 ZASPopathy). The data were collected retrospectively in 43 patients and prospectively in 3 patients. RESULTS: In patients with desminopathy, the semitendinosus was at least equally affected as the biceps femoris, and the peroneal muscles were never less involved than the tibialis anterior (sensitivity of these imaging criteria to detect desminopathy in our cohort 100%, specificity 95%). In most of the patients with myotilinopathy, the adductor magnus showed more alterations than the gracilis muscle, and the sartorius was at least equally affected as the semitendinosus (sensitivity 90%, specificity 93%). In filaminopathy, the biceps femoris and semitendinosus were at least equally affected as the sartorius muscle, and the medial gastrocnemius was more affected than the lateral gastrocnemius. The semimembranosus mostly showed more alterations than the adductor magnus (sensitivity 88%, specificity 96%). Early adult onset and cardiac involvement was most often associated with desminopathy. In patients with filaminopathy, muscle weakness typically beginning in the 5th decade of life was mostly pronounced proximally, while late adult onset (>50 years) with distal weakness was more often present in myotilinopathy. CONCLUSIONS: Muscle imaging in combination with clinical data may be helpful for separation of distinct myofibrillar myopathy subtypes and in scheduling of genetic analysis.

High-resolution myocardial perfusion imaging at 3 T: comparison to 1.5 T in healthy volunteers.

The purpose of this study was to evaluate high-resolution (HR) myocardial first-pass perfusion in healthy volunteers at 3 T compared to a typical clinical imaging protocol at 1.5 T, with respect to overall image quality and the presence of subendocardial dark rim artifacts. Myocardial first-pass rest perfusion studies were performed at both field strengths using a T1-weighted saturation-recovery segmented k-space gradient-echo sequence combined with parallel imaging (Gd-DTPA 0.05 mmol/kg). Twenty-six healthy volunteers underwent (1) a HR perfusion scan at 3 T(pixel size 3.78 mm(2)) and (2) a standard perfusion approach at 1.5 T(pixel size 9.86 mm(2)). The contrast enhancement ratio (CER) and overall image quality (4-point grading scale: 4: excellent; 1: non-diagnostic) were assessed, and a semiquantitative analysis of dark rim artifacts was performed for all studies. CER was slightly higher (1.31 +/- 0.32 vs. 1.14 +/- 0.34; p<0.01), overall image quality was significantly improved (3.03 +/- 0.43 vs. 2.37 +/- 0.39; p<0.01), and the number of dark rim artifacts (139 +/- 2.09 vs. 243 +/- 2.33; p<0.01) was significantly reduced for HR perfusion imaging at 3 T compared to the standard approach at 1.5 T. HR myocardial rest perfusion at 3 T is superior to the typical clinical perfusion protocol performed at 1.5 T with respect to the overall image quality and presence of subendocardial dark rim artifacts.

Cardiac stress MR imaging with dobutamine.

Stress testing for detection of ischemia-induced wall-motion abnormalities has become a mainstay for noninvasive diagnosis and risk stratification of patients with suspected coronary artery disease (CAD). Recent technical developments in magnetic resonance imaging (MRI), including the adoption of balanced steady-state free precession (b-SSFP) sequences-preferentially in combination with parallel imaging techniques-have led to a significant reduction of imaging time and improved patient safety. The stress protocol includes application of high-dose dobutamine (up to 40 microg/kg/min) combined with fractionated atropine (up to a maximal dose of 1.0 mg). High-dose dobutamine stress MRI revealed good sensitivity (83-96%) and specificity (80-100%) for detection of significant CAD. Myocardial tagging methods have been shown to further increase sensitivity for CAD detection. Severe complications (sustained tachycardia, ventricular fibrillation, myocardial infarction, cardiogenic shock) are rare but may be expected in 0.1-0.3% of patients. Dobutamine stress MRI has emerged as a reliable and safe clinical alternative for noninvasive assessment of CAD. New pulse sequences, such as real-time imaging, might obviate the need for breath holding and electrocardiogram (ECG) triggering in patients with severe dyspnoea and cardiac arrhythmias, which may further improve the clinical impact and acceptance of stress MRI in the future.

Biliary metal stents and air embolism: a note of caution.

Metal stents are a valuable treatment modality for patients with biliary obstruction. However, we present here two patients whose cases may serve as a warning about an unusual complication associated with these stents. We encountered this complication after endoscopic retrograde cholangiography for obstructed metal biliary stents. The first patient, an 87-year-old man with a benign biliary stricture, failed to regain consciousness after clearing of his stent using a Dormia basket and balloon catheter. Cerebral air embolism was diagnosed on cerebral computed tomography, and transesophageal echocardiography revealed a patent foramen ovale as a precipitating factor for paradoxical air embolism. He survived and was discharged with a residual hemiparesis. In the second patient, a 54-year-old man who had a history of a Billroth II operation and chronic pancreatitis and who had a portal cavernoma with biliary obstruction due to collateral veins, electromechanical dissociation complicated the balloon-catheter stent revision. Echocardiography performed during cardiopulmonary resuscitation showed major air embolism to the right heart. The patient died. These cases demonstrate that air may gain access to the venous system during therapeutic endoscopic procedures of this type. It is likely that the large diameter of metal stents and the potential for these stents to lacerate venous structures facilitate the entry of air into the venous circulation, an event which may have life-threatening consequences.