Considering Decoupled Phenotypic Diversification Between Ontogenetic Phases in Macroevolution: An Example Using Triggerfishes (Balistidae).

Across the Tree of Life, most studies of phenotypic disparity and diversification have been restricted to adult organisms. However, many lineages have distinct ontogenetic phases that differ from their adult forms in morphology and ecology. Focusing disproportionately on the evolution of adult forms unnecessarily hinders our understanding of the pressures shaping evolution over time. Non-adult disparity patterns are particularly important to consider for coastal ray-finned fishes, which can have juvenile phases with distinct phenotypes. These juvenile forms are often associated with sheltered nursery environments, with phenotypic shifts between adults and juvenile stages that are readily apparent in locomotor morphology. Whether this ontogenetic variation in locomotor morphology reflects a decoupling of diversification dynamics between life stages remains unknown. Here we investigate the evolutionary dynamics of locomotor morphology between adult and juvenile triggerfishes. We integrate a time-calibrated phylogenetic framework with geometric morphometric approaches and measurement data of fin aspect ratio and incidence, and reveal a mismatch between morphospace occupancy, the evolution of morphological disparity, and the tempo of trait evolution between life stages. Collectively, our results illuminate how the heterogeneity of morpho-functional adaptations can decouple the mode and tempo of morphological diversification between ontogenetic stages.

Muscle diffusion tensor imaging in facioscapulohumeral muscular dystrophy.

INTRODUCTION/AIMS: Muscle diffusion tensor imaging has not yet been explored in facioscapulohumeral muscular dystrophy (FSHD). We assessed diffusivity parameters in FSHD subjects compared with healthy controls (HCs), with regard to their ability to precede any fat replacement or edema. METHODS: Fat fraction (FF), water T2 (wT2), mean, radial, axial diffusivity (MD, RD, AD), and fractional anisotropy (FA) of thigh muscles were calculated in 10 FSHD subjects and 15 HCs. All parameters were compared between FSHD and controls, also exploring their gradient along the main axis of the muscle. Diffusivity parameters were tested in a subgroup analysis as predictors of disease involvement in muscle compartments with different degrees of FF and wT2 and were also correlated with clinical severity scores. RESULTS: We found that MD, RD, and AD were significantly lower in FSHD subjects than in controls, whereas we failed to find a difference for FA. In contrast, we found a significant positive correlation between FF and FA and a negative correlation between MD, RD, and AD and FF. No correlation was found with wT2. In our subgroup analysis we found that muscle compartments with no significant fat replacement or edema (FF < 10% and wT2 < 41 ms) showed a reduced AD and FA compared with controls. Less involved compartments showed different diffusivity parameters than more involved compartments. DISCUSSION: Our exploratory study was able to demonstrate diffusivity parameter abnormalities even in muscles with no significant fat replacement or edema. Larger cohorts are needed to confirm these preliminary findings.

Intestinal Microbiota and Derived Metabolites in Myocardial Fibrosis and Postoperative Atrial Fibrillation.

The high incidence of atrial fibrillation (AFib) following cardiac surgery (postoperative atrial fibrillation, POAF) relies on specific surgical features. However, in the setting of POAF, the role of the microbiome in the modulation of cardiac fibrosis is still not clear. This study aimed to analyze the effect of the microbiome and its main metabolic product (trimethylamine-N-oxide, TMAO) in the fibrosis of myocardial tissue, to investigate its role in POAF. Patients undergoing elective cardiac surgery with cardiopulmonary bypass, central atrio-caval cannulation and no history of AFib, were included. A fragment of the right atrium was analyzed for qualitative and mRNA-quantitative evaluation. A preoperative blood sample was analyzed with enzyme-linked immunosorbent assay (ELISA). A total of 100 patients have been included, with POAF occurring in 38%. Histologically, a higher degree of fibrosis, angiogenesis and inflammation has been observed in POAF. Quantitative evaluation showed increased mRNA expression of collagen-1, collagen-3, fibronectin, and transforming growth factor beta (TGFb) in the POAF group. ELISA analysis showed higher levels of TMAO, lipopolysaccharide and TGFb in POAF, with similar levels of sP-selectin and zonulin. TMAO ≥ 61.8 ng/mL (odds ratio, OR 2.88 [1.35-6.16], p = 0.006), preoperative hemoglobin < 13.1 g/dL (OR 2.37 [1.07-5.24], p = 0.033) and impaired right ventricular function (OR 2.38 [1.17-4.83], p = 0.017) were independent predictors of POAF. Also, TMAO was significantly associated with POAF by means of increased fibrosis. Gut microbiome product TMAO is crucial for myocardial fibrosis, which is a key factor for POAF. Patients in preoperative sinus rhythm who will develop POAF have increased genetic expression of pro-fibrotic genes and enhanced fibrosis in histological staining. Elevated TMAO level (≥61.8 ng/mL) is an independent risk factor for POAF.

Assessment of idiopathic inflammatory myopathy using a deep learning method for muscle T2 mapping segmentation.

OBJECTIVE: To investigate the utility of an automatic deep learning (DL) method for segmentation of T2 maps in patients with idiopathic inflammatory myopathy (IIM) against healthy controls, and also the association of quantitative T2 values in patients with laboratory and pulmonary findings. METHODS: Structural MRI and T2 mapping of bilateral thigh muscles from patients with IIM and healthy volunteers were segmented using dedicated software based on a pre-trained convolutional neural network. Incremental and federated learning were implemented for continuous adaptation and improvement. Muscle T2 values derived from DL segmentation were compared between patients and healthy controls, and T2 values of patients were further analyzed with serum muscle enzymes, and interstitial lung disease (ILD) which was diagnosed and graded based on chest HRCT. RESULTS: Overall, 64 patients (27 patients with dermatomyositis, 29 with polymyositis, and 8 with antisynthetase syndrome (ASS)) and 10 healthy controls were included. By using DL-based muscle segmentation, T2 values generated from T2 maps accurately differentiated patients from those of controls (p < 0.001) with a cutoff value of 36.4 ms (sensitivity 96.9%, and specificity 100%). In patients with IIM, muscle T2 values positively correlated with all the serum muscle enzymes (all p < 0.05). ILD score of patients with ASS was markedly higher than that of those without ASS (p = 0.011), while dissociation between the severity of muscular involvement and ILD was observed (p = 0.080). CONCLUSION: Automatic DL could be used to segment thigh muscles and help quantitatively assess muscular inflammation of IIM through T2 mapping. KEY POINTS: • Muscle T2 mapping automatically segmented by deep learning can differentiate IIM from healthy controls. • T2 value, an indicator of active muscle inflammation, positively correlates with serum muscle enzymes. • T2 mapping can detect muscle disease in patients with normal muscle enzyme levels.

Revascularization of Occluded Right Coronary Artery and Outcome After Coronary Artery Bypass Grafting.

OBJECTIVES: The aim of the present study was to evaluate the results of isolated coronary artery bypass grafting (CABG) with or without revascularization of the occluded right coronary artery (RCA). METHODS: Patients undergoing isolated CABG were included in a prospective European multicenter registry. Outcomes were adjusted for imbalance in preoperative variables with propensity score matching analysis. Late outcomes were evaluated with Kaplan-Meier's method and competing risk analysis. RESULTS: Out of 2,948 included in this registry, 724 patients had a total occlusion of the RCA and were the subjects of this analysis. Occluded RCA was not revascularized in 251 (34.7%) patients with significant variability between centers. Among 245 propensity score-matched pairs, patients with and without revascularization of occluded RCA had similar early outcomes. The nonrevascularized RCA group had increased rates of 5-year all-cause mortality (17.7 vs. 11.7%, p = 0.039) compared with patients who had their RCA revascularized. The rates of myocardial infarction and repeat revascularization were only numerically increased but contributed to a significantly higher rate of MACCE (24.7 vs. 15.7%, p = 0.020) at 5 year among patients with nonrevascularized RCA. CONCLUSION: In this multicenter study, one-third of totally occluded RCAs was not revascularized during isolated CABG for multivessel coronary artery disease. Failure to revascularize an occluded RCA in these patients increased the risk of all-cause mortality and MACCEs at 5 years.

Impact of Surgeon Experience and Centre Volume on Outcome After Off-Pump Coronary Artery Bypass Surgery: Results From the European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG) Registry.

AIM: The aim of this study was to assess the impact of surgeon experience and centre volume on early operative outcomes in patients undergoing off-pump coronary artery bypass (OPCAB) surgery. METHOD: Of 7,352 patients in the European Multicenter Study on Coronary Artery Bypass Grafting (E-CABG) registry, 1,549 underwent OPCAB and were included in the present analysis. Using adjusted regression analysis, we compared major early adverse events after procedures performed by experienced OPCAB surgeons (i.e., ≥20 cases per year; n=1,201) to those performed by non-OPCAB surgeons (n=348). Furthermore, the same end points were compared between procedures performed by OPCAB surgeons in high OPCAB volume centres (off-pump technique used in >50% of cases; n=894) and low OPCAB volume centres (n=307). RESULTS: In the experienced OPCAB surgeon group, we observed shorter procedure times (ß -43.858, 95% confidence interval [CI] -53.322 to -34.393; p<0.001), a lower rate of conversion to cardiopulmonary bypass (odds ratio [OR] 0.284, 95% CI 0.147-0.551; p<0.001), a lower rate of prolonged inotrope or vasoconstrictor use (OR 0.492, 95% CI 0.371-0.653; p<0.001), a lower rate of early postprocedural percutaneous coronary interventions (OR 0.335, 95% CI 0.169-0.663; p=0.002), and lower 30-day mortality (OR 0.423, 95% CI 0.194-0.924; p=0.031). In high OPCAB volume centres, we found a lower rate of prolonged inotrope use (OR 0.584, 95% CI 0.419-0.814; p=0.002), a lower rate of postprocedural acute kidney injury (OR 0.382, 95% CI 0.198-0.738; p=0.004), shorter duration of intensive care unit (ß -1.752, 95% CI -2.240 to -1.264; p<0.001) and hospital (ß -1.967; 95% CI -2.717 to -1.216; p<0.001) stays, and lower 30-day mortality (OR 0.316, 95% CI 0.114-0.881; p=0.028). CONCLUSIONS: Surgeon experience and centre volume may play an important role on the early outcomes after OPCAB surgery.

MRI lung lobe segmentation in pediatric cystic fibrosis patients using a recurrent neural network trained with publicly accessible CT datasets.

PURPOSE: To introduce a widely applicable workflow for pulmonary lobe segmentation of MR images using a recurrent neural network (RNN) trained with chest CT datasets. The feasibility is demonstrated for 2D coronal ultrafast balanced SSFP (ufSSFP) MRI. METHODS: Lung lobes of 250 publicly accessible CT datasets of adults were segmented with an open-source CT-specific algorithm. To match 2D ufSSFP MRI data of pediatric patients, both CT data and segmentations were translated into pseudo-MR images that were masked to suppress anatomy outside the lung. Network-1 was trained with pseudo-MR images and lobe segmentations and then applied to 1000 masked ufSSFP images to predict lobe segmentations. These outputs were directly used as targets to train Network-2 and Network-3 with non-masked ufSSFP data as inputs, as well as an additional whole-lung mask as input for Network-2. Network predictions were compared to reference manual lobe segmentations of ufSSFP data in 20 pediatric cystic fibrosis patients. Manual lobe segmentations were performed by splitting available whole-lung segmentations into lobes. RESULTS: Network-1 was able to segment the lobes of ufSSFP images, and Network-2 and Network-3 further increased segmentation accuracy and robustness. The average all-lobe Dice similarity coefficients were 95.0 ± 2.8 (mean ± pooled SD [%]) and 96.4 ± 2.5, 93.0 ± 2.0; and the average median Hausdorff distances were 6.1 ± 0.9 (mean ± SD [mm]), 5.3 ± 1.1, 7.1 ± 1.3 for Network-1, Network-2, and Network-3, respectively. CONCLUSION: Recurrent neural network lung lobe segmentation of 2D ufSSFP imaging is feasible, in good agreement with manual segmentations. The proposed workflow might provide access to automated lobe segmentations for various lung MRI examinations and quantitative analyses.

Mechanical circulatory support in patients with cardiogenic shock not secondary to cardiotomy: a network meta-analysis.

To compare the efficacy and safety of different mechanical circulatory support (MCS) devices in CS. A total of 24 studies (7 randomized controlled trials-RCTs-and 17 non-RCTs) involving 11,117 patients were entered in a Bayesian network meta-analysis. The primary endpoint was 30-day mortality. Secondary endpoints were stroke and bleeding (requiring transfusion and/or intracranial and/or fatal). Compared with no MCS, extra-corporeal membrane oxygenation (ECMO) reduced 30-day mortality when used both alone (OR 0.37, 95% CrI 0.15-0.90) and together with the micro-axial pump Impella (OR 0.13, 95% CrI 0.02-0.80) or intra-aortic balloon pump (IABP) (OR 0.19, 95% CrI 0.05-0.63), although the relevant articles were affected by significant publication bias. Consistent results were obtained in a sensitivity analysis including only studies of CS due to myocardial infarction. After halving the weight of studies with a non-RCT design, only the benefit of ECMO + IABP on 30-day mortality was maintained (OR 0.22, 95% CI 0.057-0.76). The risk of bleeding was increased by TandemHeart (OR 13, 95% CrI 3.50-59), Impella (OR 5, 95% CrI 1.60-18), and IABP (OR 2.2, 95% CrI 1.10-4.4). No significant differences were found across MCS strategies regarding stroke. Although limited by important quality issues, the studies performed so far indicate that ECMO, especially if combined with Impella or IABP, reduces short-term mortality in CS. MCS increases the hazard of bleeding.

Analysis of HIV quasispecies and virological outcome of an HIV D+/R+ kidney-liver transplantation.

INTRODUCTION: Transplantation among HIV positive patients may be a valuable therapeutic intervention. This study involves an HIV D+/R+ kidney-liver transplantation, where PBMC-associated HIV quasispecies were analyzed in donor and transplant recipients (TR) prior to transplantation and thereafter, together with standard viral monitoring. METHODS: The donor was a 54 year of age HIV infected woman: kidney and liver recipients were two HIV infected men, aged 49 and 61. HIV quasispecies in PBMC was analyzed by ultra-deep sequencing of V3 env region. During TR follow-up, plasma HIV-1 RNA, HIV-1 DNA in PBMC, analysis of proviral integration sites and drug-resistance genotyping were performed. Other virological and immunological monitoring included CMV and EBV DNA quantification in blood and CD4 T cell counts. RESULTS: Donor and TR were all ART-HIV suppressed at transplantation. Thereafter, TR maintained a nearly suppressed HIV-1 viremia, but HIV-1 RNA blips and the increase of proviral integration sites in PBMC attested some residual HIV replication. A transient peak in HIV-1 DNA occurred in the liver recipient. No major changes of drug-resistance genotype were detected after transplantation. CMV and EBV transient reactivations were observed only in the kidney recipient, but did not require specific treatment. CD4 counts remained stable. No intermixed quasispecies between donor and TR was observed at transplantation or thereafter. Despite signs of viral evolution in TR, HIV genetic heterogeneity did not increase over the course of the months of follow up. CONCLUSIONS: No evidence of HIV superinfection was observed in the donor nor in the recipients. The immunosuppressive treatment administrated to TR did not result in clinical relevant viral reactivations.

Daily Caffeine Intake Induces Concentration-Dependent Medial Temporal Plasticity in Humans: A Multimodal Double-Blind Randomized Controlled Trial.

Caffeine is commonly used to combat high sleep pressure on a daily basis. However, interference with sleep-wake regulation could disturb neural homeostasis and insufficient sleep could lead to alterations in human gray matter. Hence, in this double-blind, randomized, cross-over study, we examined the impact of 10-day caffeine (3 × 150 mg/day) on human gray matter volumes (GMVs) and cerebral blood flow (CBF) by fMRI MP-RAGE and arterial spin-labeling sequences in 20 habitual caffeine consumers, compared with 10-day placebo (3 × 150 mg/day). Sleep pressure was quantified by electroencephalographic slow-wave activity (SWA) in the previous nighttime sleep. Nonparametric voxel-based analyses revealed a significant reduction in GMV in the medial temporal lobe (mTL) after 10 days of caffeine intake compared with 10 days of placebo, voxel-wisely adjusted for CBF considering the decreased perfusion after caffeine intake compared with placebo. Larger GMV reductions were associated with higher individual concentrations of caffeine and paraxanthine. Sleep SWA was, however, neither different between conditions nor associated with caffeine-induced GMV reductions. Therefore, the data do not suggest a link between sleep depth during daily caffeine intake and changes in brain morphology. In conclusion, daily caffeine intake might induce neural plasticity in the mTL depending on individual metabolic processes.

Deep learning for automatic segmentation of thigh and leg muscles.

OBJECTIVE: In this study we address the automatic segmentation of selected muscles of the thigh and leg through a supervised deep learning approach. MATERIAL AND METHODS: The application of quantitative imaging in neuromuscular diseases requires the availability of regions of interest (ROI) drawn on muscles to extract quantitative parameters. Up to now, manual drawing of ROIs has been considered the gold standard in clinical studies, with no clear and universally accepted standardized procedure for segmentation. Several automatic methods, based mainly on machine learning and deep learning algorithms, have recently been proposed to discriminate between skeletal muscle, bone, subcutaneous and intermuscular adipose tissue. We develop a supervised deep learning approach based on a unified framework for ROI segmentation. RESULTS: The proposed network generates segmentation maps with high accuracy, consisting in Dice Scores ranging from 0.89 to 0.95, with respect to "ground truth" manually segmented labelled images, also showing high average performance in both mild and severe cases of disease involvement (i.e. entity of fatty replacement). DISCUSSION: The presented results are promising and potentially translatable to different skeletal muscle groups and other MRI sequences with different contrast and resolution.

Prognostic value of SARS-CoV-2 on patients undergoing cardiac surgery.

OBJECTIVE: To analyze Italian Cardiac Surgery experience during the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) identifying risk factors for overall mortality according to coronavirus disease 2019 (COVID-19) status. METHODS: From February 20 to May 31, 2020, 1354 consecutive adult patients underwent cardiac surgery at 22 Italian Centers; 589 (43.5%), patients came from the red zone. Based on COVID-19 status, 1306 (96.5%) were negative to SARS-CoV-2 (COVID-N), and 48 (3.5%) were positive to SARS-CoV-2 (COVID-P); among the COVID-P 11 (22.9%) and 37 (77.1%) become positive, before and after surgery, respectively. Surgical procedures were as follows: 396 (29.2%) isolated coronary artery bypass grafting (CABG), 714 (52.7%) isolated non-CABG procedures, 207 (15.3%) two associate procedures, and three or more procedures in 37 (2.7%). Heart failure was significantly predominant in group COVID-N (10.4% vs. 2.5%, p = .01). RESULTS: Overall in-hospital mortality was 1.6% (22 cases), being significantly higher in COVID-P group (10 cases, 20.8% vs. 12, 0.9%, p < .001). Multivariable analysis identified COVID-P condition as a predictor of in-hospital mortality together with emergency status. In the COVID-P subgroup, the multivariable analysis identified increasing age and low oxygen saturation at admission as risk factors for in-hospital mortality. CONCLUSION: As expected, SARS-CoV-2 infection, either before or soon after cardiac surgery significantly increases in-hospital mortality. Moreover, among COVID-19-positive patients, older age and poor oxygenation upon admission seem to be associated with worse outcomes.

Coronary Artery Bypass Grafting in Patients With High Risk of Bleeding.

BACKGROUND: Postoperative bleeding after cardiac surgery is associated with increased morbidity and mortality. We tested the hypothesis that patients with a preoperatively estimated high risk of severe perioperative bleeding may have impaired early outcome after on-pump versus off-pump coronary artery bypass grafting (CABG). METHOD: Data from 7,352 consecutive patients who underwent isolated CABG from January 2015 to May 2017 were included in the multicentre European Coronary Artery Bypass Grafting registry. The postoperative bleeding risk was estimated using the WILL-BLEED risk score. Of all included patients, 3,548 had an increased risk of severe perioperative bleeding (defined as a WILL-BLEED score ≥4) and were the subjects of this analysis. We compared the early outcomes between patients who underwent on-pump or off-pump CABG using a multivariate mixed model for risk-adjusted analysis. RESULTS: Off-pump surgery was performed in 721 patients (20.3%). On-pump patients received more packed red blood cell units (on-pump: 1.41 [95% confidence interval {CI} 0.99-1.86]; off-pump: 0.86 [95% CI 0.64-1.08]; p<0.001), had a longer stay in the intensive care unit (on-pump: 4.4 [95% CI 3.6-8.1] days; off-pump: 3.2 [95% CI 2.0-4.4] days; p=0.049), and a higher rate of postoperative atrial fibrillation (on-pump: 46.5% [95% CI 34.9-58.1]; off-pump: 31.3% [95% CI 21.7-40.9]; p=0.025). Furthermore, on-pump patients showed a trend towards a higher rate of postoperative stroke (on-pump: 2.4% [95% CI 0.9-4.1]; off-pump: 1.1 [95% CI 0.2-2.7]; p=0.094). CONCLUSION: Our data suggest that in patients with an increased risk of bleeding, the use of cardiopulmonary bypass is associated with higher morbidity. These patients may benefit from off-pump surgery if complete revascularisation can be ensured.

One-minute whole-brain magnetization transfer ratio imaging with intrinsic B1 -correction.

PURPOSE: Magnetization transfer ratio (MTR) histograms are used widely for the assessment of diffuse pathological changes in the brain. For broad clinical application, MTR scans should not only be fast, but confounding factors should also be minimized for high reproducibility. To this end, a 1-minute whole-brain spiral MTR method with intrinsic B1 -field correction is introduced. METHODS: A spiral multislice spoiled gradient-echo sequence with adaptable magnetization-transfer saturation pulses (angle ß) is proposed. After a low-resolution single-shot spiral readout and a dummy preparation period, high-resolution images are acquired using an interleaved spiral readout. For whole-brain MTR imaging, 50 interleaved slices with three different magnetization-transfer contrasts (ß = 0°, 350°, and 550°) together with an intrinsic B1 -field map are recorded in 58.5 seconds on a clinical 3T system. From the three contrasts, two sets of MTR images are derived and used for subsequent B1 correction, assuming a linear dependency on ß. For validation, a binary spin bath model is used. RESULTS: For the proposed B1 -correction scheme, numerical simulations indicate for brain tissue a decrease of about a factor of 10 for the B1 -related bias on MTR. As a result, following B1 correction, MTR differences in gray and white matter become markedly accentuated, and the reproducibility of MTR histograms from scan-rescan experiments is improved. Furthermore, B1 -corrected MTR histograms show a lower variability for age-matched normal-appearing brain tissue. CONCLUSION: From its speed and offering intrinsic B1 correction, the proposed method shows excellent prospects for clinical studies that explore magnetization-transfer effects based on MTR histogram analysis.

The impact of segmentation on whole-lung functional MRI quantification: Repeatability and reproducibility from multiple human observers and an artificial neural network.

PURPOSE: To investigate the repeatability and reproducibility of lung segmentation and their impact on the quantitative outcomes from functional pulmonary MRI. Additionally, to validate an artificial neural network (ANN) to accelerate whole-lung quantification. METHOD: Ten healthy children and 25 children with cystic fibrosis underwent matrix pencil decomposition MRI (MP-MRI). Impaired relative fractional ventilation (RFV ) and relative perfusion (RQ ) from MP-MRI were compared using whole-lung segmentation performed by a physician at two time-points (At1 and At2 ), by an MRI technician (B), and by an ANN (C). Repeatability and reproducibility were assess with Dice similarity coefficient (DSC), paired t-test and Intraclass-correlation coefficient (ICC). RESULTS: The repeatability within an observer (At1 vs At2 ) resulted in a DSC of 0.94 ± 0.01 (mean ± SD) and an unsystematic difference of -0.01% for RFV (P = .92) and +0.1% for RQ (P = .21). The reproducibility between human observers (At1 vs B) resulted in a DSC of 0.88 ± 0.02, and a systematic absolute difference of -0.81% (P < .001) for RFV and -0.38% (P = .037) for RQ . The reproducibility between human and the ANN (At1 vs C) resulted in a DSC of 0.89 ± 0.03 and a systematic absolute difference of -0.36% for RFV (P = .017) and -0.35% for RQ (P = .002). The ICC was >0.98 for all variables and comparisons. CONCLUSIONS: Despite high overall agreement, there were systematic differences in lung segmentation between observers. This needs to be considered for longitudinal studies and could be overcome by using an ANN, which performs as good as human observers and fully automatizes MP-MRI post-processing.

Variable echo time imaging for detecting the short T2* components of the sciatic nerve: a validation study.

OBJECTIVE: The aim of this study was to develop and validate an MRI protocol based on a variable echo time (vTE) sensitive to the short T2* components of the sciatic nerve. MATERIALS AND METHODS: 15 healthy subjects (M/F: 9/6; age: 21-62) were scanned at 3T targeting the sciatic nerve at the thigh bilaterally, using a dual echo variable echo time (vTE) sequence (based on a spoiled gradient echo acquisition) with echo times of 0.98/5.37 ms. Apparent T2* (aT2*) values of the sciatic nerves were calculated with a mono-exponential fit and used for data comparison. RESULTS: There were no significant differences in aT2* related to side, sex, age, and BMI, even though small differences for side were reported. Good-to-excellent repeatability and reproducibility were found for geometry of ROIs (Dice indices: intra-rater 0.68-0.7; inter-rater 0.70-0.72) and the related aT2* measures (intra-inter reader ICC 0.95-0.97; 0.66-0.85) from two different operators. Side-related signal-to-noise-ratio non-significant differences were reported, while contrast-to-noise-ratio measures were excellent both for side and echo. DISCUSSION: Our study introduces a novel MR sequence sensitive to the short T2* components of the sciatic nerve and may be used for the study of peripheral nerve disorders.

Correlated Evolution of Sex Allocation and Mating System in Wrasses and Parrotfishes.

In accordance with predictions of the size-advantage model, comparative evidence confirms that protogynous sex change is lost when mating behavior is characterized by weak size advantage. However, we lack comparative evidence supporting the adaptive significance of sex change. Specifically, it remains unclear whether increasing male size advantage induces transitions to protogynous sex change across species, as it can within species. We show that in wrasses and parrotfishes (Labridae) the evolution of protogynous sex change is correlated with polygynous mating and that the degree of male size advantage expressed by polygynous species influences transitions between different types of protogynous sex change. Phylogenetic reconstructions reveal strikingly similar patterns of sex allocation and mating system evolution with comparable lability. Despite the plasticity of sex-determination mechanisms in labrids, transitions trend toward monandry (all males derived from sex-changed females), with all observed losses of protogyny accounted for by shifts in the timing of sex change to prematuration. Likewise, transitions in mating system trend from the ancestral condition of lek-like polygyny toward greater male size advantage, characteristic of haremic polygyny. The results of our comparative analyses are among the first to confirm the adaptive significance of sex change as described by the size-advantage model.

On the optimal temporal resolution for phase contrast cardiovascular magnetic resonance imaging: establishment of baseline values.

BACKGROUND: The aim of this study is to quantify the frequency content of the blood velocity waveform in different body regions by means of phase contrast (PC) cardiovascular magnetic resonance (CMR) and Doppler ultrasound. The highest frequency component of the spectrum is inversely proportional to the ideal temporal resolution to be used for the acquisition of flow-sensitive imaging (Shannon-Nyquist theorem). METHODS: Ten healthy subjects (median age 33y, range 24-40) were scanned with a high-temporal-resolution PC-CMR and with Doppler ultrasound on three body regions (carotid arteries, aorta and femoral arteries). Furthermore, 111 patients (median age 61y) with mild to moderate arterial hypertension and 58 patients with aortic aregurgitation, atrial septal defect, or repaired tetralogy of Fallot underwent aortic CMR scanning. The frequency power distribution was calculated for each location and the maximum frequency component, fmax, was extracted and expected limits for the general population were inferred. RESULTS: In the healthy subject cohort, significantly different fmax values were found across the different body locations, but they were nonsignificant across modalities. No significant correlation was found with heart rate. The measured fmax ranged from 7.7 ± 1.1 Hz in the ascending aorta, up to 12.3 ± 5.1 Hz in the femoral artery (considering PC-CMR data). The calculated upper boundary for the general population ranged from 11.0 Hz to 27.5 Hz, corresponding to optimal temporal resolutions of 45 ms and 18 ms, respectively. The patient cohort exhibited similar values for the frequencies in the aorta, with no correlation between blood pressure and frequency content. CONCLUSIONS: The temporal resolution of PC-CMR acquisitions can be adapted based on the scanned body region and in the adult population, should approach approximately 20 ms in the peripheral arteries and 40 ms in the aorta. TRIAL REGISTRATION: This study presents results from a restrospective analysis of the clinical study NCT01870739 (ClinicalTrials.gov).

Dynamic MR imaging of the skeletal muscle in young and senior volunteers during synchronized minimal neuromuscular electrical stimulation.

OBJECTIVE: Neuromuscular electrical stimulation (NMES)-induced isometric contraction is feasible during MRI and can be combined with acquisition of volumetric dynamic MR data, in a synchronous and controlled way. Since NMES is a potent resource for rehabilitation, MRI synchronized with NMES presents a valuable validation tool. Our aim was to show how minimal NMES-induced muscle contraction characterization, as evaluated through phase-contrast MRI, differs between senior and young volunteers. MATERIALS AND METHODS: Simultaneous NMES of the quadriceps muscle and phase-contrast imaging were applied at 3 T to 11 senior (75 ± 3 years) and 12 young volunteers (29 ± 7 years). A current sufficient to induce muscle twitch without knee extension was applied to both groups. RESULTS: Strain vectors were extracted from the velocity fields and strain datasets were compared with non-parametric tests and descriptive statistics. Strain values were noticeably different between both groups at both current intensities and significant differences were observed for similar current level. DISCUSSION: In conclusion, NMES-synchronized MRI could be successfully applied in senior volunteers with strain results clearly different from the younger volunteers. Also, differences within the senior group were detected both in the magnitude of strain and in the position of maximum strain pixels.

A Nomogram for Predicting Long Length of Stay in The Intensive Care Unit in Patients Undergoing CABG: Results From the Multicenter E-CABG Registry.

OBJECTIVE: Many papers evaluated predictive factors for prolonged intensive care unit (ICU) stay after cardiac surgery, but efforts in translating those models in practical clinical tools is lacking. The aim of this study was to build a new nomogram score and test its calibration and discrimination power for predicting a long length of stay in the ICU among patients undergoing coronary artery bypass graft surgery (CABG). DESIGN: Retrospective analysis of an international registry. SETTING: Multicentric. PARTICIPANTS: Based on the european multicenter study on coronary artery bypass grafting (E-CABG) registry (NCT02319083), a total of 7,352 consecutive patients who underwent isolated CABG were analyzed. INTERVENTIONS: A "long length of stay" in the ICU was considered when equal to or more than 3 days. Predictive factors were analyzed through a multivariate logistic regression model that was used for the nomogram. RESULTS: Long length of ICU stay was observed in 2,665 patients (36.2%). Ten independent variables were included in the final regression model: the SYNTAX score class critical preoperative state, left ventricular ejection fraction class, angina at rest, poor mobility, recent potent antiplatelet use, estimated glomerular filtration rate class, body mass index, sex, and age. Based on this 10-risk factors logistic regression model, a nomogram has been designed. CONCLUSION: The authors defined a nomogram model that can provide an individual prediction of long length of ICU stay in cardiovascular surgical patients undergoing CABG. This type of model would allow an early recognition of high-risk patients who might receive different preoperative and postoperative treatments to improve outcomes.