Towards a consensus regarding global signal regression for resting state functional connectivity MRI

The number of resting state functional connectivity MRI studies continues to expand at a rapid rate along with the options for data processing. Of the processing options, few have generated as much controversy as global signal regression and the subsequent observation of negative correlations (anti-correlations). This debate has motivated new processing strategies and advancement in the field, but has also generated significant confusion and contradictory guidelines. In this article, we work towards a consensus regarding global signal regression. We highlight several points of agreement including the fact that there is not a single “right” way to process resting state data that reveals the “true” nature of the brain. Although further work is needed, different processing approaches likely reveal complementary insights about the brain's functional organisation

Dispensing error and near miss recording in Irish community pharmacies

Background: Community pharmacies in the Republic of Ireland are required to have a clear and documented system for the management, review and recording of dispensing errors (DEs) and near misses (NMs). Despite this, only 66% of pharmacies inspected in Ireland maintained error or incident logs in 2016 [1]. DEs causing serious patient harm are infrequent; however, their consequences, including death, can be devastating [2]. Aims: To assess the reporting incidence of DEs and NMs in community pharmacies in the Republic of Ireland, and compliance with national guidelines on their management. Method: An invitation was sent to all community pharmacies in Ireland (n = 1,688) to participate in an anonymous, proforma, online survey using LimeSurvey. Data collected include general pharmacy information, data on DEs recorded, data on NMs recorded, and data on compliance with recording DEs and NMs over the period 1/1/2019‐30/6/2019. A DE was defined as an any error detected after the medication had been given to the patient or their representative. An NMs was defined as any error that was detected before the patient or patient's representative was handed the dispensed prescription. Results: One hundred and twenty‐four (7.3%) full or partial responses were received. Independent pharmacies accounted for 52.2% of respondents. 1/96 (0.7%) of pharmacies reported not recording DEs or NMs, while 2/124 (1.5%) pharmacies did not have a Standard Operating Procedure for recording DEs and NMs. Most pharmacies (83/96, 86.6%) manually recorded their DEs and NMs and approximately 2‐in‐3 (69/95, 72.6%) pharmacies reported regularly reviewing DEs and NMs. The mean self‐reported DE rate was 0.035% while the mean NM rate was 0.135%. The mean ratio of NMs to DEs was 4.7:1. A correlation was observed between the number of items dispensed and the rate of DEs (r = −0.354, p = 0.002). The top three recorded DEs were incorrect strength (32.1%), incorrect drug (16.7%), and incorrect quantity (13.5%). The top three recorded causes were picking errors (28.0%), similar packaging (16.6%), and similar drug names (14.5%). Pharmacies rated themselves as less compliant in recording NMs (mean: 5.3 on a 10‐point scale) than DEs (mean: 7.5/10). Conclusion: Dispensing errors and near misses in Irish community pharmacies get reported at a similar rate than in other countries. A nationwide reporting program, similar to the ones used in other countries, such as England, Wales, New Zealand, and Sweden, could improve reporting rates, make data analysis easier, and allow pharmacists to learn from their own and others' mistakes, thereby preventing dispensing errors from happening and improving patient outcomes

Vascular physiology drives functional brain networks

We present the first evidence for vascular regulation driving fMRI signals in specific functional brain networks. Using concurrent neuronal and vascular stimuli, we collected 30 BOLD fMRI datasets in 10 healthy individuals: a working memory task, flashing checkerboard stimulus, and CO2 inhalation challenge were delivered in concurrent but orthogonal paradigms. The resulting imaging data were averaged together and decomposed using independent component analysis, and three “neuronal networks” were identified as demonstrating maximum temporal correlation with the neuronal stimulus paradigms: Default Mode Network, Task Positive Network, and Visual Network. For each of these, we observed a second network component with high spatial overlap. Using dual regression in the original 30 datasets, we extracted the time-series associated with these network pairs and calculated the percent of variance explained by the neuronal or vascular stimuli using a normalized R2 parameter. In each pairing, one network was dominated by the appropriate neuronal stimulus, and the other was dominated by the vascular stimulus as represented by the end-tidal CO2 time-series recorded in each scan. We acquired a second dataset in 8 of the original participants, where no CO2 challenge was delivered and CO2 levels fluctuated naturally with breathing variations. Although splitting of functional networks was not robust in these data, performing dual regression with the network maps from the original analysis in this new dataset successfully replicated our observations. Thus, in addition to responding to localized metabolic changes, the brain’s vasculature may be regulated in a coordinated manner that mimics (and potentially supports) specific functional brain networks. Multi-modal imaging and advances in fMRI acquisition and analysis could facilitate further study of the dual nature of functional brain networks. It will be critical to understand network-specific vascular function, and the behavior of a coupled vascular-neural network, in future studies of brain pathology

Coping strategies of healthcare professional students for stress incurred during their studies: a literature review

Background: Stress in healthcare professional students is well-documented, however coping strategies and their relationship with stress has not been comprehensively reviewed. It is necessary for students to use positive coping strategies to effectively reduce stress levels. Aims: The aim of this review is to identify coping strategies of healthcare professional students and their consequences. Methods: Studies conducted from 2010 to 2020 on coping strategies utilised by healthcare students were reviewed. An electronic database search was performed in January 2020 of three databases CINAHL, SCOPUS and PubMed. Results: Twenty-two studies were included in this review, using a wide range of survey instruments including the Brief Coping Orientation to Problems Experienced (Brief COPE) Inventory and the Coping Behaviour Inventory Common coping strategies utilised by healthcare students include problem-focused strategies such as planning, problem-solving and active coping. Coping strategies tended to vary depending on student’s location, year of their course, gender and age. Positive coping strategies, such as problem-focused strategies, were associated with reduced stress levels and improved psychological health. Other emotion-focused coping strategies identified included acceptance, self-distraction, and optimism. Conclusions: Findings may provide direction for third-level institutions in designing interventions (such as encouraging exercise) promoting the use of positive coping strategies

Arterial CO2 fluctuations modulate neuronal rhythmicity: Implications for MEG and fMRI studies of resting-state networks

A fast emerging technique for studying human resting state networks (RSNs) is based on spontaneous temporal fluctuations in neuronal oscillatory power, as measured by magnetoencephalography. However, it has been demonstrated recently that this power is sensitive to modulations in arterial CO2 concentration. Arterial CO2 can be modulated by natural fluctuations in breathing pattern, as might typically occur during the acquisition of an RSN experiment. Here, we demonstrate for the first time the fine-scale dependence of neuronal oscillatory power on arterial CO2 concentration, showing that reductions in alpha, beta, and gamma power are observed with even very mild levels of hypercapnia (increased arterial CO2). We use a graded hypercapnia paradigm and participant feedback to rule out a sensory cause, suggesting a predominantly physiological origin. Furthermore, we demonstrate that natural fluctuations in arterial CO2, without administration of inspired CO2, are of a sufficient level to influence neuronal oscillatory power significantly in the delta-, alpha-, beta-, and gamma-frequency bands. A more thorough understanding of the relationship between physiological factors and cortical rhythmicity is required. In light of these findings, existing results, paradigms, and analysis techniques for the study of resting-state brain data should be revisited

Imaging of ischemia, obstruction and infection in the abdomen

Intestinal ischemia is a serious condition that continues to be associated with mortalities in excess of 70%. Intestinal obstruction and gastrointestinal tract sepsis are common conditions, accounting for a large proportion of patients admitted to emergency departments with acute abdominal symptoms. This article discusses the imaging methods and key findings of these entities in the emergency radiology department. The article includes imaging examples, diagnostic options, protocol selections, diagnostic criteria, and differential diagnoses

Changes in arterial cerebral blood volume during lower body negative pressure measured with MRI

Cerebral Autoregulation (CA), defined as the ability of the cerebral vasculature to maintain stable levels of blood flow despite changes in systemic blood pressure, is a critical factor in neurophysiological health. Magnetic resonance imaging (MRI) is a powerful technique for investigating cerebrovascular function, offering high spatial resolution and wide fields of view (FOV), yet it is relatively underutilized as a tool for assessment of CA. The aim of this study was to demonstrate the potential of using MRI to measure changes in cerebrovascular resistance in response to lower body negative pressure (LBNP). A Pulsed Arterial Spin Labeling (PASL) approach with short inversion times (TI) was used to estimate cerebral arterial blood volume (CBVa) in eight healthy subjects at baseline and -40mmHg LBNP. We estimated group mean CBVa values of 3.13±1.00 and 2.70±0.38 for baseline and lbnp respectively, which were the result of a differential change in CBVa during -40 mmHg LBNP that was dependent on baseline CBVa. These data suggest that the PASL CBVa estimates are sensitive to the complex cerebrovascular response that occurs during the moderate orthostatic challenge delivered by LBNP, which we speculatively propose may involve differential changes in vascular tone within different segments of the arterial vasculature. These novel data provide invaluable insight into the mechanisms that regulate perfusion of the brain, and establishes the use of MRI as a tool for studying CA in more detail