Discriminative Analysis of Brain Functional Connectivity Patterns for Mental Fatigue Classification

Mental fatigue is a commonly experienced state that can be induced by placing heavy demands on cognitive systems. This often leads to lowered productivity and increased safety risks. In this study, we developed a functional-connectivity based mental fatigue monitoring method. Twenty-six subjects underwent a 20-min mentally demanding test of sustained attention with high-resolution EEG monitoring. Functional connectivity patterns were obtained on the cortical surface via source localization of cortical activities in the first and last 5-min quartiles of the experiment. Multivariate pattern analysis was then adopted to extract the highly discriminative functional connectivity information. The algorithm used in the present study demonstrated an overall accuracy of 81.5% (p < 0.0001) for fatigue classification through leave-one-out cross validation. Moreover, we found that the most discriminative connectivity features were located in or across middle frontal gyrus and several motor areas, in agreement with the important role that these cortical regions play in the maintenance of sustained attention. This work therefore demonstrates the feasibility of a functional-connectivity-based mental fatigue assessment method, opening up a new avenue for modeling natural brain dynamics under different mental states. Our method has potential applications in several domains, including traffic and industrial safety.     

Imaging-based algorithmic approach to gallbladder wall thickening

Gallbladder(GB) wall thickening is a frequent finding caused by a spectrum of conditions. It is observed in many extracholecystic as well as intrinsic GB conditions. GB wall thickening can either be diffuse or focal. Diffuse wall thickening is a secondary occurrence in both extrinsic and intrinsic pathologies of GB, whereas, focal wall thickening is mostly associated with intrinsic GB pathologies. In the absence of specific clinical features, accurate etiological diagnosis can be challenging. The survival rate in GB carcinoma(GBC) can be improved if it is diagnosed at an early stage, especially when the tumor is confined to the wall. The pattern of wall thickening in GBC is often confused with benign diseases, especially chronic cholecystitis, xanthogranulomatous cholecystitis, and adenomyomatosis. Early recognition and differentiation of these conditions can improve the prognosis. In this minireview, the authors describe the patterns of abnormalities on various imaging modalities(conventional as well as advanced) for the diagnosis of GB wall thickening. This paper also illustrates an algorithmic approach for the etiological diagnosis of GB wall thickening and suggests a formatted reporting for GB wall abnormalities.     

Sodium-glucose linked transporter-2 inhibitor renal outcome modification in type 2 diabetes: Evidence from studies in patients with high or low renal risk

Data from three completed cardiovascular outcome trials (CVOTs), EMPA-REG OUTCOME, CANVAS Program and DECLARE-TIMI 58, add to the evidence supporting the potential renoprotective effects of sodium-glucose linked transporter-2 (SGLT2) inhibitors in patients with type 2 diabetes. Despite recommendations in recent guidelines, it is difficult to support a view that definitive evidence for renoprotection exists from these SGLT2 inhibitor CVOT results. To date, the only dedicated trial to report definitive data on the renal impact of SGLT2 inhibition is CREDENCE. Notably, the total number of patient-relevant renal endpoint events (dialysis, transplant or renal death) observed in CREDENCE was significantly higher than the total for all three CVOTs collectively (183 events/4401 patients vs. 69 events/34 322 patients, respectively), which shows the increased statistical power of CREDENCE for these renal endpoints. Treatment with canagliflozin was associated with a 30% relative risk reduction (RRR) in the primary composite endpoint of end-stage kidney disease, doubling of serum creatinine, or death from renal or cardiovascular causes and a 34% RRR for the renal-specific elements of this primary endpoint (P <0.001). Canagliflozin has therefore become the first US-approved SGLT2 inhibitor to include an indication for RRR, in addition to type 2 diabetes glycaemic control and cardiovascular risk reduction. While confirmatory of the exploratory data from CVOTs, CREDENCE provides the first robust data on the effects of canagliflozin on patient-relevant renal endpoints. Extrapolation to a conclusion of a SGLT2 inhibitor class effect cannot be made until additional renal trials with other SGLT2 inhibitors are reported.     

Alcohol and vagal tone as triggers for paroxysmal atrial fibrillation

Alcohol and vagal activity may be important triggers for paroxysmal atrial fibrillation (PAF), but it remains unknown if these associations occur more often than would be expected by chance alone because of the lack of a comparator group in previous studies. We compared self-reported frequency of these triggers in patients with PAF to those with other supraventricular tachycardias (SVTs). Consecutive consenting patients presenting for electrophysiology procedures at a single university medical center underwent a structured interview regarding arrhythmia triggers. Two hundred twenty-three patients with a documented arrhythmia (133 with PAF and 90 with SVT) completed the survey. After multivariable adjustment, patients with PAF had a 4.42 greater odds (95% confidence interval [CI] 1.35 to 14.44) of reporting alcohol consumption (p = 0.014) and a 2.02 greater odds (95% CI 1.02 to 4.00) of reporting vagal activity (p = 0.044) as an arrhythmia trigger compared to patients with SVT. In patients with PAF, drinking primarily beer was associated with alcohol as a trigger (odds ratio [OR] 4.49, 95% CI 1.41 to 14.28, p = 0.011), whereas younger age (OR 0.68, 95% CI 0.49 to 0.95, p = 0.022) and a family history of AF (OR 5.73, 95% CI 1.21 to 27.23, p = 0.028) each were independently associated with having vagal activity provoke an episode. Patients with PAF and alcohol triggers were more likely to have vagal triggers (OR 10.32, 95% CI 1.05 to 101.42, p = 0.045). In conclusion, alcohol consumption and vagal activity elicit PAF significantly more often than SVT. Alcohol and vagal triggers often were found in the same patients with PAF, raising the possibility that alcohol may precipitate AF by vagal mechanisms.     

Open and hybrid deep vein reconstructions: to do or not to do?

Endovascular reconstruction has become the standard treatment of chronic obstruction of large veins. Stenting is done with increasing frequency to treat iliac venous obstructions, with or without associated inferior vena caval or femoral vein occlusions. Open reconstruction with venous bypass is performed today in patients who fail attempts at venous stenting or who are not candidates for endovascular reconstructions. Patients with primary or secondary malignancies invading the vena cava undergo open caval reconstruction at the time of tumour excision. Open venous reconstructions are still preferred in patients with large vein injuries due to blunt or penetrating trauma or in those who suffer iatrogenic venous injuries. Hybrid reconstruction can be performed with endophlebectomy of the common femoral or femoral veins combined with iliofemoral stenting.     

In vivo laser speckle imaging reveals microvascular remodeling and hemodynamic changes during wound healing angiogenesis

Laser speckle contrast imaging (LSCI) is a high-resolution and high contrast optical imaging technique often used to characterize hemodynamic changes in short-term physiological experiments. In this study, we demonstrate the utility of LSCI for characterizing microvascular remodeling and hemodynamic changes during wound healing angiogenesis in vivo. A 2 mm diameter hole was made in the mouse ear and the periphery of the wound imaged in vivo using LSCI over 12 days. We were able to visualize and quantify the vascular and perfusion changes that accompanied wound healing in the microenvironment proximal to the wound, and validated these changes with histology. We found that consistent with the stages of wound healing, microvessel density increased during the initial inflammatory phase (i.e., day 0–3), stayed elevated through the tissue formation phase (i.e., until day 7) and returned to baseline during the tissue remodeling phase (i.e., by day 12). Concomitant “wide area mapping” of blood flow revealed that tissue perfusion in the wound periphery initially decreased, gradually increased from day 3–7, and subsided as healing completed. Interestingly, some regions exhibited a reestablishment of tissue perfusion approximately 6 days earlier than the ~18 days usually reported for the long term remodeling phase. The results from this study demonstrate that LSCI is an ideal platform for elucidating in vivo changes in microvascular hemodynamics and angiogenesis, and has the potential to offer invaluable insights in a range of disease models involving abnormal hemodynamics, such as diabetes and tumors.