Comparison of the reverse bevel versus Franseen type endoscopic ultrasound needle

BACKGROUND Reverse bevel(RB) needle is widely used for endoscopic ultrasound fine needle biopsy(EUS-FNB). A 3-plane symmetrical needle with Franseen geometry(FG) has recently become available.AIM To compare the clinical efficacy of FG to that of RB needle.METHODS A retrospective cohort study of all adult patients who underwent EUS-FNB for solid and mixed lesions either with 22 G RB needle or 22 G FG needle between January 2016 and February 2019 was undertaken. All cytology slides were reviewed by an independent gastrointestinal cytopathologist blinded to the needle used and the initial cytology report. The primary and secondary outcomes were to assess the sample adequacy using Euro-cytology criteria and the number of cell clusters, respectively.RESULTS Two hundred and twenty six procedures were included in the study. RB needle was used in 128 procedures and FG needle in 98 procedures. The baseline characteristics of both groups were comparable. On multivariable analysis, FG needle(P = 0.02) and location of the lesion(P 0.01) were independently associated with adequate tissue. Further, the use of FG needle(P = 0.04) and the size of the lesion(P = 0.02) were independently associated with acquisition of increased number of cell clusters.CONCLUSION FG needle is superior to RB needle in acquiring adequate tissue and attaining higher number of cell clusters for solid and mixed lesions.     

Localizing evoked and induced responses to faces using magnetoencephalography

A rich pattern of responses in frequency, time and space are known to be generated in the visual cortex in response to faces. Recently, a number of studies have used magnetoencephalography (MEG) to try to record these responses non‐invasively – in many cases using source analysis techniques based on the beamforming method. Here we sought both to characterize best practice for measuring face‐specific responses using MEG beamforming, and to determine whether the results produced by the beamformer match evidence from other modalities. We measured activity to visual presentation of face stimuli and phase‐scrambled control stimuli, and performed source analyses of both induced and evoked responses using Synthetic Aperture Magnetometry. We localized the gamma‐band response to bilateral lateral occipital cortex, and both the gamma‐band response and the M170‐evoked response to the right fusiform gyrus. Differences in the gamma‐band response between faces and scrambled stimuli were confined to the frequency range 50–90 Hz; gamma‐band activity at higher frequencies did not differ between the two stimulus categories. We additionally identified a component of the M220‐evoked response – localized to the parieto‐occipital sulcus – which was enhanced for scrambled vs. unscrambled faces. These findings help to establish that MEG beamforming can localize face‐specific responses in time, frequency and space with good accuracy (when validated against established findings from functional magnetic resonance imaging and intracranial recordings), as well as contributing to the establishment of best methodological practice for the use of the beamformer method to measure face‐specific responses.     

Neural correlates of the LSD experience revealed by multimodal neuroimaging

Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD’s marked effects on the visual cortex did not significantly correlate with the drug’s other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of “ego-dissolution” and “altered meaning,” implying the importance of this particular circuit for the maintenance of “self” or “ego” and its processing of “meaning.” Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or “psychedelic” that alters consciousness in a profound and characteristic way. First synthesized in 1938, its extraordinary psychological properties were not discovered until 1943 (1). LSD would go on to have a major effect on psychology and psychiatry in the 1950s and 1960s; however, increasing recreational use and its influence on youth culture provoked the drug’s being made illegal in the late 1960s. As a consequence, human research with LSD has been on pause for half a century. However, inspired by a revival of research with other psychedelics, such as psilocybin and ayahuasca, a small number of new reports on the psychological effects of LSD have recently been published (2–6).LSD has a high affinity for a range of different neurotransmitter receptors, but its characteristic psychological effects are thought to be mediated by serotonin 2A receptor (5-HT_2AR) agonism (7). Previous neurophysiological research with LSD is limited to electroencephalography (EEG) studies in the 1950s and 1960s. These reported reductions in oscillatory power, predominantly in the lower-frequency bands, and an increase in the frequency of alpha rhythms (8). Broadband decreases in cortical oscillatory power have been observed in modern EEG and magnetoencephalography (MEG) studies with psilocybin (9, 10), with EEG and the dimethyltryptamine-containing brew “ayahuasca” (11), and with rodent brain local-field potential recordings and a range of different 5-HT_2AR agonists (12–14).The effects of psychedelics (other than LSD) on human brain activity have also previously been investigated with positron emission tomography (PET) (15) and functional magnetic resonance imaging (fMRI) (16). fMRI studies with psilocybin revealed decreased cerebral blood flow (CBF) and blood oxygen level-dependent (BOLD) signal in connector hubs (16), decreased resting state functional connectivity (RSFC) in major resting state networks (RSNs) such as the default-mode network (DMN) (17), and the emergence of novel patterns of communication (18, 19), whereas increased cortical glucose metabolism was found with PET (15). Notably, the spatial locations of the PET-, fMRI-, EEG-, and MEG-measured effects of psychedelics are relatively consistent; for example, high-level cortical regions, such as the posterior cingulate cortex (PCC), and some of the principal effects of psilocybin revealed by fMRI (e.g., decreased DMN RSFC) were recently replicated by a separate team working with ayahuasca (20).Consistent with a prior hypothesis (17), these studies suggest that an “entropic” effect on cortical activity is a key characteristic of the psychedelic state. However, a putative excitation of hippocampal/parahippocampal gyri activity has also been observed with fMRI and psychedelics in humans (19) and animals (14). Moreover, depth EEG studies in the 1950s reported activations in medial temporal lobe regions during psychosis-like states under LSD and other psychedelics (21, 22). Further, patients with epilepsy with resection of the medial temporal lobes showed attenuated LSD effects postsurgery (23), and electrical stimulation of medial temporal lobe circuitry produces visual hallucinations of somewhat similar nature to those produced by psychedelics [e.g., distorted visual perception (24) and dreamlike “visions” (25)].The present study sought to investigate the acute brain effects of LSD in healthy volunteers, using a comprehensive placebo-controlled neuroimaging design incorporating ASL, BOLD signal measures, and MEG resting state scans. It was predicted that major RSNs (e.g., the DMN) and hippocampal/parahippocampal gyri circuitry would be implicated in the drug’s mechanism of action.Twenty healthy participants attended two scanning days (LSD and placebo) at least 2 wk apart in a balanced-order, within-subjects design. Sessions included an fMRI followed by a MEG scan, each lasting 75 min. Data were acquired during eye-closed, task-free, “resting state” conditions. Drug/placebo were administered in solution and injected i.v. over the course of 2 min. Two resting state ASL scans totaling 16 min were completed 100 min after i.v. administration of LSD (75 µg in 10 mL saline) or placebo (10 mL saline), corresponding to the initial phase of the peak subjective effects of LSD (peak effects were reached ∼120–150 min postinfusion). Two resting state BOLD scans totaling 14 min were completed 135 min postinfusion, and two resting state MEG scans totaling 14 min were completed 225 min postinfusion. All analyses applied multiple comparison correction (SI Appendix) and two-tailed hypothesis testing unless particularly strong prior hypotheses were held.     

A Survey of Expert Practice and Attitudes Regarding Advanced Imaging Modalities in Surveillance of Barrett’s Esophagus

Background

Published guidelines do not address what the minimum incremental diagnostic yield (IDY) for detection of dysplasia/cancer is required over the standard Seattle protocol for an advanced imaging modality (AIM) to be implemented in routine surveillance of Barrett’s esophagus (BE) patients. We aimed to report expert practice patterns and attitudes, specifically addressing the minimum IDY in the use of AIMs in BE surveillance.

Methods

An international group of BE experts completed an anonymous electronic survey of domains relevant to surveillance practice patterns and use of AIMs. The evaluated AIMs were conventional chromoendoscopy (CC), virtual chromoendoscopy (VC), volumetric laser endomicroscopy (VLE), confocal laser endomicroscopy (CLE), and wide-area transepithelial sampling (WATS^3D). Responses were recorded using five-point balanced Likert items and analyzed as continuous variables.

Results

The survey response rate was 84% (61/73)—41 US and 20 non-US. Experts were most comfortable with and routinely use VC and CC, and least comfortable with and rarely use VLE, CLE, and WATS^3D. Experts rated data from randomized controlled trials (1.4?±?0.9) and guidelines (2.6?±?1.2) as the two most influential factors for implementing AIMs in clinical practice. The minimum IDY of AIMs over standard biopsies to be considered of clinical benefit was lowest for VC (15%, IQR 10–29%) and highest for VLE (30%, IQR 20–50%). Compared to US experts, non-US experts reported higher use of CC for BE surveillance (p?<?0.001).

Conclusion

These results should inform benchmarks that need to be met for guidelines to recommend the routine use of AIMs in the surveillance of BE patients.

     

fMRI of thermal pain: effects of stimulus laterality and attention.

Brain activity was studied by fMRI in 18 healthy subjects during stimulation of the thenar eminence of the hand with either warm (non-painful, 40 degrees C) or hot (painful, 46-49 degrees C) stimuli using a contact thermode. Experiments were performed on the right and left hand independently and with two attentional contexts: subjects either attended to pain or attended to a visual global motion discrimination task (to distract them from pain). Group analysis demonstrated that attended warm stimulation of the right hand did not produce any significantly activated clusters. Painful thermal stimulation of either hand elicited significant activity over a large network of brain regions, including insula, inferior frontal gyrus, cingulate gyrus, secondary somatosensory cortex, cerebellum, and medial frontal gyrus (corrected P < 0.05). Insula activity was distributed along its anterior-posterior axis and depended on the hand stimulated and attentional context. In particular, activity within the posterior insula was contralateral to the site of stimulation, tested using regions of interest (ROI) analysis: significant side x site interaction (P = 0.001). With attention diverted from the painful stimulus bilateral anterior insula activity moved posteriorly to midinsula and decreased in extent (ROI analysis: significant main effect of attention (P = 0.03)). The role of the insula in thermosensation and attention is discussed.     

White light endoscopy, narrow band imaging and chromoendoscopy with magnification in diagnosing colorectal neoplasia

AIM: To evaluate the sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of 3 different techniques: high resolution white light endoscopy (WLE), Narrow Band Imaging (NBI) and Chromoendoscopy (CHR), all with magnification in differentiating adenocarcinomas, adenomatous and hyperplastic colorectal polyps.METHODS: Each polyp was sequentially assessed first by WLE, followed by NBI and finally by CHR. Digital images of each polyp with each modality were taken and stored. Biopsies or polypectomies were then performed followed by blinded histopathological analysis. Each image was blindly graded based on the Kudo’s pit pattern (KPP). In the assessment with NBI, the mesh brown capillary network pattern (MBCN) of each polyp was also described. The Sn, Sp, PPV and NPV of differentiating hyperplastic (Type I & II-KPP, Type I-MBCN) adenomatous (Types III, IV-KPP, Type II-MBCN) and carcinomatous polyps (Type V-KPP, Type III-MCBN) was then compared with reference to the final histopathological diagnosis.RESULTS: A total of 50 colorectal polyps (5 adenocarcinomas, 38 adenomas, 7 hyperplastic) were assessed. CHR and NBI [KPP, MBCN or the combined classification (KPP & MBCN)] were superior to WLE in the prediction of polyp histology (P < 0.001, P = 0.002, P = 0.001 and P < 0.001, respectively). NBI, using the MBCN pattern or the combined classification showed higher numerical accuracies compared to CHR, but this was not statistically significant (P = 0.625, 0.250).CONCLUSION: This feasibility study demonstrated that this combined classification with NBI could potentially be useful in routine clinical practice, allowing the endoscopist to predict histology with higher accuracies using a less cumbersome and technically less challenging method.