Mean Vessel Diameter Research Articles

Noncontrast free-breathing ECG-gated 3D balanced steady-state free precession in congenital heart disease and aortopathy evaluation.

High-fidelity cardiac magnetic resonance (MR) imaging plays a pivotal role in the surveillance of congenital heart disease (CHD) and aortopathy. We aimed to evaluate the quality and accuracy of free breathing, ECG-gated noncontrast three-dimensional (3D) balanced steady-state free precession (bSSFP) in cases of CHDs and aortopathies using contrast-enhanced 3D bSSFP as a reference. We also used one of our routinely used non-ECG-gated 2D-single-shot (SSh) bSSFP sequence as an adjunct to noncontrast 3D bSSFP. Institutional review board approval was obtained to perform a systematic retrospective analysis of image quality and vascular measurements. Patients with CHD and aortopathy, who were undergoing clinically indicated contrast-enhanced 3D bSSFP, were prospectively identified to also undergo additional noncontrast 3D bSSFP and 2D SSh bSSFP imaging as part of a clinical quality improvement initiative aimed at reducing the use of contrast when feasible. Two readers, blinded to each other's evaluations, graded image quality on a 5-point Likert scale and performed vascular measurements in separate sessions for both 3D bSSFP images. They also reported the visibility of various mediastinal great vessels on 2D SSh bSSFP images. Raw agreement, the weighted kappa statistic, and intra-class correlation coefficients (ICCs) were computed to assess the consistency and agreement between the two readers. Comparative analysis of noncontrast and contrast-enhanced 3D bSSFP imaging was performed in adult and pediatric patients using a two-sided paired t-test and Bland-Altman analysis. A P-value < 0.05 was considered significant for all inference testing. A total of 29 patients (17 males, median age 20.3years, interquartile range (IQR) 12.5, age range 7-39years), including 11 pediatric patients under the age of 18years (6 males, median age 14.5years, IQR 4.0, age range 7-17years), underwent retrospective analysis. The overall image quality score for contrast-enhanced 3D bSSFP was significantly higher (P < 0.0001) than that of noncontrast 3D bSSFP for both all subjects (4.4 ± 0.2, range 4.0-4.9 vs 3.7 ± 0.4, range 3.1-4.7) and only pediatric subjects (4.3 ± 0.3, range 4.0-4.9 vs 3.6 ± 0.5, range 3.1-4.4). By combining noncontrast 3D bSSFP and 2D bSSFP, reader 1 and reader 2 rated 423 and 420 vessels diagnostic, respectively, in a total of 435 vessel segments. All landmarks showed similar mean vessel diameters without significant differences between noncontrast and contrast-enhanced 3D bSSFP MR angiography (r = 0.99, bias -0.31mm, 95% limits of agreement -2.04mm to 1.43mm). Although contrast-enhanced images had better overall image quality, an imaging protocol consisting of noncontrast 2D SSh bSSFP and 3D bSSFP whole-chest images provides diagnostically adequate image quality, and accurate vascular measurements, comparable to free-breathing contrast-enhanced 3D bSSFP in both children and adults with CHD and aortopathies.

Quantitative assessment of colour fundus photography in hyperopia children based on artificial intelligence

ObjectivesThis study aimed to quantitatively evaluate optic nerve head and retinal vascular parameters in children with hyperopia in relation to age and spherical equivalent refraction (SER) using artificial intelligence (AI)-based...

Vascular feature identification in actinic keratosis grades I-III using dynamic optical coherence tomography with automated, quantitative analysis

Clinical grading of actinic keratosis (AK) is based on skin surface features, while subclinical alterations are not taken into consideration. Dynamic optical coherence tomography (D-OCT) enables quantification of the skin´s vasculature, potentially helpful to improve the link between clinical and subclinical features. We aimed to compare microvascular characteristics across AK grades using D-OCT with automated vascular analysis. This explorative study examined AK and photodamaged skin (PD) on the face or scalp. AKs were clinically graded according to the Olsen Classification scheme before D-OCT assessment. Using an open-source software tool, the OCT angiographic analyzer (OCTAVA), we quantified vascular network features, including total and mean vessel length, mean vessel diameter, vessel area density (VAD), branchpoint density (BD), and mean tortuosity from enface maximum intensity projection images. Additionally, we performed subregional analyses on selected scans to overcome challenges associated with imaging through hyperkeratosis (each lesion group; n = 18). Our study included 45 patients with a total of 205 AKs; 93 grade I lesions, 65 grade II, 47 grade III and 89 areas with PD skin. We found that all AK grades were more extensively vascularized relative to PD, as shown by greater total vessel length and VAD (p ≤ 0.009). Moreover, AKs displayed a disorganized vascular network, with higher BD in AK I-II (p < 0.001), and mean tortuosity in AK II-III (p ≤ 0.001) than in PD. Vascularization also increased with AK grade, showing significantly greater total vessel length in AK III than AK I (p = 0.029). Microvascular quantification of AK unveiled subclinical, quantitative differences among AK grades I-III and PD skin. D-OCT-based microvascular assessment may serve as a supplement to clinical AK grading, potentially raising perspectives to improve management strategies.

VALIDATION OF QUANTITATIVE FLOW RATIO DERIVED VIRTUAL ANGIOPLASTY WITH POST–ANGIOPLASTY FRACTIONAL FLOW RESERVE. THE QIMERA–I STUDY

Abstract Backgroud Quantitative flow ratio (QFR) virtual angioplasty with pre–PCI residual QFR showed better results compared with angiographic approach to assess post–PCI functional results. However correlation with pre–PCI residual QFR and post–PCI fractional flow reserve (FFR) is lacking. Methods Multicenter prospective study including consecutive patientswith angiographically 50–90% coronary lesions and positive QFR result. All patients were evaluated with QFR, hyperemic and non–hyperemic pressure ratios (NHPR) before and after the index PCI. Pre–PCI residual QFR (virtual angioplasty) was calculated and compared with post–PCI fractional flow reserve (FFR), QFR and NHPR. Results A total of 84 patients with 92 treated coronary lesions were included, with a mean age of 65.5±10.9 years and 59% of single vessel lesion being the left anterior descending artery in 69%. The mean vessel diameter was 2.82±0.41 mm. Procedural success was achieved in all cases, with a mean number of implanted stents of 1.17±0.46. Baseline QFR value was 0.69 ± 0.12 and baseline FFR and NHPR were 0.73 + 0.08 and 0.82 + 0.11, respectively. Mean post–PCI FFR increased to 0.87 ±0.05 whereas residual QFR had been estimated as 0.95 ± 0.05 showing poor correlation with post–PCI FFR (0.163; 95%CI:0.078–0.386) and a low diagnostic accuracy (30.9%, 95%CI:20–43%). Conclusions In this analysis, the results of QFR–based virtual angioplasty did not seem to accurately correlate with post–PCI FFR.

Quantitative Microvascular Change Analysis Using a Semi-Automated Software in Macula-off Rhegmatogenous Retinal Detachment Assessed by Swept-Source Optical Coherence Tomography Angiography.

Objective: To analyze the performance of custom semi-automated software for quantitative analysis of retinal capillaries in eyes with macula-off rhegmatogenous retinal detachment (RRD) and the role of these microvascular measures as potential biomarkers of postoperative visual outcomes. Methods: A prospective, observational, and single-center study was conducted on consecutive patients who underwent 25G pars-plana vitrectomy for primary uncomplicated macula-off RRD. Optical coherence tomography angiography (OCTA) was performed in the fellow and RRD eyes before surgery and in months 1, 3, and 6 after surgery. The preoperative values of the fellow eyes were used as surrogates of macula-off ones. The primary endpoints were the mean vessel diameter index (VDI); vessel area density (VAD); and vessel skeleton density (VSD) at month 6. Results: Forty-four eyes (44 patients) were included in the study. Considering the fellow eyes as a surrogate of preoperative values of macula-off eyes, VDI in superficial (SCP) and deep (DCP) capillary plexuses was significantly reduced at month 6 (p = 0.0087 and p = 0.0402, respectively); whereas VSD in SCP increased significantly from preoperative values (p = 0.0278). OCTA built-in software parameters were significantly reduced from month 1 to month 6 in both SCP and DCP (p values ranged between 0.0235 and <0.0001). At month 6, 25 (56.8%) eyes achieved a best-corrected visual acuity BCVA ≥ 0.3 (LogMAR). The greater the preoperative BCVA, the greater the probability of achieving good visual outcomes (Odds ratio: 11.06; p = 0.0037). However, none of the OCTA parameters were associated with the probability of achieving a BCVA improvement ≥ 0.3. Conclusions: Quantitative evaluation of capillary density and morphology through OCTA and semi-automated software represents a valuable tool for clinical assessment and managing the disease comprehensively.

Effects of Glutamine Synthetase on Neovascularization in Glioma: In Vivo MR Vessel Size Imaging and Histology.

Glutamine Synthetase (GS) could induce vascular sprouting through the improvement of endothelial cell migration in inflammatory diseases. MR vessel-size imaging has been proposed as a valuable approach for visualizing the underlying angiogenic processes in the brain. This study aims to investigate the role of GS in the neovascularization of gliomas through the utilization of MR vessel-size imaging and histopathological techniques. In this exploratory animal study, we randomly divided the C6 glioma rat models into a control group and an L-methionine sulfoximine (MSO) treatment group. Daily intraperitoneal injections were administered for three consecutive days, starting from day 10 following the implantation of C6 glioma cells in rats. Subsequently, MR vessel size imaging was conducted using a BRUKER 7 T/200 mm MRI scanner, and the MRI results were validated through histopathological examination. A significant decrease in microvessel density was observed in both the tumor periphery and center areas in the MSO treatment group compared to that in the control group. The mean vessel diameter (mVD) and vessel size index (VSI) did not exhibit significant changes compared to the control group. Moreover, the staining intensity of platelet endothelial cell adhesion molecule-1 (CD31) and GS in the tumor periphery was significantly decreased in the MSO treatment group. Additionally, the MSO treatment demonstrated a substantial inhibition of tumor growth. GS inhibitors significantly reduced angiogenesis in the periphery area of C6 glioma, exerting an inhibitory effect on tumor progression. Thus, GS inhibitors could be potential therapeutic agents for treating glioma. Additionally, in vivo MR vessel size imaging detects changes in vascularrelated parameters after tumor treatment, making it a promising method for detecting neovascularization in glioma.</p>.

Root topological order drives variation of fine root vessel traits and hydraulic strategies in tropical trees.

Vessel traits contribute to plant water transport from roots to leaves and thereby influence how plants respond to soil water availability, but the sources of variation in fine root anatomical traits remain poorly understood. Here, we explore the variations of fine root vessel traits along topological orders within and across tropical tree species. Anatomical traits were measured along five root topological orders in 80 individual trees of 20 species from a tropical forest in southwestern China. We found large variations for most root anatomical traits across topological orders, and strong co-variations between vessel traits. Within species, theoretical specific xylem hydraulic conductivity (Kth) increased with topological order due to increased mean vessel diameter, size heterogeneity, and decreased vessel density. Across species, Kth was associated with vessel fraction in low-order roots and correlated with mean vessel diameter and vessel density in high-order roots, suggesting a shift in relative anatomical contributors to Kth from the second- to fifth-order roots. We found no clear relationship between Kth and stele: root diameter ratios. Our study shows strong variations in root vessel traits across topological orders and species, and highlights shifts in the anatomical underpinnings by varying vessel-related anatomical structures for an optimized water supply.

Longitudinal Monitoring of Angiogenesis in a Murine Window Chamber Model In Vivo.

Angiogenesis induced by growth factor administration, which can augment the blood supply in regenerative applications, has drawn wide attention in medical research. Longitudinal monitoring of vascular structure and development in vivo is important for understanding and evaluating the dynamics of involved biological processes. In this work, a dual-modality imaging system consisting of photoacoustic microscopy (PAM) and optical coherence tomography (OCT) was applied for noninvasive in vivo imaging of angiogenesis in a murine model. Fibrin scaffolds, with and without basic fibroblast growth factor (bFGF), were implanted in a flexible imaging window and longitudinally observed over 9 days. Imaging was conducted at 3, 5, 7, and 9 days after implantation to monitor vascularization in and around the scaffold. Several morphometric parameters were derived from the PAM images, including vessel area density (VAD), total vessel length (TVL), and vessel mean diameter (VMD). On days 7 and 9, mice receiving bFGF-laden fibrin gels exhibited significantly larger VAD and TVL compared to mice with fibrin-only gels. In addition, VMD significantly decreased in +bFGF mice versus fibrin-only mice on days 7 and 9. Blood vessel density, evaluated using immunohistochemical staining of explanted gels and underlying tissue on day 9, corroborated the findings from the PAM images. Overall, the experimental results highlight the utility of a dual-modality imaging system in longitudinally monitoring of vasculature in vivo with high resolution and sensitivity, thereby providing an effective tool to study angiogenesis.

Anti-RAGE (Receptor Advanced Glycation End products) Antibody Improves Diabetic Retinopathy in Rats via Hypoglycemic and Anti-inflammatory Mechanism

Background: Receptor advanced glycation end products (RAGE) activation plays an essential role in diabetic retinopathy (DR) progression. This study was aimed to explore the role of anti-RAGE antibodies (RAGE antagonists) in inhibiting DR progression through their hypoglycemic and anti- inflammatory mechanism in diabetic retinopathy induced rats.&#x0D; Methods: A total of 30 male Wistar rats were randomly divided into five group. The group was consisted of normal control group, DR group without treatment, DR group with anti-RAGE 1 g/kg BW, 10 g/kg BW, and 100 g/kg BW. To assess the diabetic retinopathy, fundus photographs were taken every week using a camera with 16x magnification placed in front of the rat's eyes. Blood glucose was checked by the glucose oxidase-peroxidase method. Retinal TNF-? levels and VEGF were examined using an enzyme-linked immunosorbent assay (ELISA) kit.&#x0D; Results: The finding of this study showed that anti-RAGE treatment at dose of 10 and 100 g/kg BW, HbA1c levels were significantly higher (p&lt; 0.05) compared to the normal control group but significantly lower (p&lt; 0.05) than in the diabetes group. The mean blood vessel diameter in the DR+anti-RAGE 10 and 100 g/kg BW groups was significantly lower than in the diabetic retinopathy group (p&lt; 0.05). The administration of anti-RAGE 10 and 100 g/kg BW showed the ability to significantly reduce VEGF levels compared to the DR group (p&lt; 0.05).&#x0D; Conclusions: This study revealed at doses of 10 and 100 g/kg BW, anti-RAGE antibodies improved diabetic retinopathy in Wistar rats through hypoglycemic effects and anti-inflammatory mechanisms.

Super‐resolution ultrasound localization microscopy for the non‐invasive imaging of human testicular microcirculation and its differential diagnosis role in male infertility

AbstractTesticular microcirculation is closely related to spermatogenic function and seminiferous tubular function. The diagnosis and monitoring of testicular diseases can be associated with testicular microcirculation; however, there are currently no effective non‐invasive methods for super‐resolution imaging of testicular microcirculation. In this study, we introduced state‐of‐the‐art graph‐based tracking with the Kalman motion model algorithm to non‐invasively image human testicular microcirculation for the first time with a regular frame‐rate clinical ultrasound imaging system (37 Hz). Two distinct testicular vessels with an 81 µm separation were resolved in the testicular vasculature, surpassing all other imaging modalities. In a retrospective study, we performed contrast‐enhanced ultrasound examinations(CEUS) and ultrasound localization microscopy (ULM) processing on the included 76 infertile patients and 15 healthy controls from August 2021 to May 2023 and obtained super‐resolution images of testicular microcirculation with sub‐diffraction resolution. Through the results of one‐way analysis of variance tests and receiver operating characteristic analyses, we found that the ULM‐based parameters hold promise as clinical guidance for differentiating between non‐obstructive and obstructive male infertility. The mean vessel diameter achieved an area under the curve (AUC) of 0.920 (95% confidence interval [CI]: 0.847–0.994, p &lt; .001) with a cut‐off value of 170.9 µm in oligoasthenospermia, and an AUC of 0.952 (95% CI: 0.875–1.000, p &lt; .001) with a cut‐off value of 169.9 µm in azoospermia patients, respectively, addressing a significant clinical challenge.

Validation of Quantitative Flow Ratio-Derived Virtual Angioplasty with Post-Angioplasty Fractional Flow Reserve-The QIMERA-I Study.

Background: Quantitative flow ratio (QFR) virtual angioplasty with pre-PCI residual QFR showed better results compared with an angiographic approach to assess post-PCI functional results. However, correlation with pre-PCI residual QFR and post-PCI fractional flow reserve (FFR) is lacking. Methods: A multicenter prospective study including consecutive patients with angiographically 50-90% coronary lesions and positive QFR results. All patients were evaluated with QFR, hyperemic and non-hyperemic pressure ratios (NHPR) before and after the index PCI. Pre-PCI residual QFR (virtual angioplasty) was calculated and compared with post-PCI fractional flow reserve (FFR), QFR and NHPR. Results: A total of 84 patients with 92 treated coronary lesions were included, with a mean age of 65.5 ± 10.9 years and 59% of single vessel lesions being the left anterior descending artery in 69%. The mean vessel diameter was 2.82 ± 0.41 mm. Procedural success was achieved in all cases, with a mean number of implanted stents of 1.17 ± 0.46. The baseline QFR value was 0.69 ± 0.12 and baseline FFR and NHPR were 0.73 ± 0.08 and 0.82 ± 0.11, respectively. Mean post-PCI FFR increased to 0.87 ± 0.05 whereas residual QFR had been estimated as 0.95 ± 0.05, showing poor correlation with post-PCI FFR (0.163; 95% CI:0.078-0.386) and low diagnostic accuracy (30.9%, 95% CI:20-43%). Conclusions: In this analysis, the results of QFR-based virtual angioplasty did not seem to accurately correlate with post-PCI FFR.

Ecophysiological Behavior of Fagus sylvatica L. Growing at Its Southern Distribution Limit: Insights for Understanding the Fate of the European Beech under Warmer and Dryer Growth Conditions

In the last 20 years, a significant mortality of Fagus sylvatica L. (European beech) has been documented in central and northern European forests. Surprisingly, no beech die off occurred at the southern limit. This fact leads us to hypothesize that European beech populations growing at the southern limit of the distribution might have a significant phenotypic plasticity to better cope with low water availability and rising temperatures. To check this hypothesis, we evaluated the ecophysiological behavior of F. sylvatica growing along an altitudinal transect in Calabria (Italy). We selected three study sites (750 m a.s.l., 976 m a.sl. m a.s.l., 1450 m a.s.l.) showing narrow ranges of temperature, rainfall and air humidity. Trees growing at 976 m a.s.l. showed the highest stomatal conductance values during the entire experimental period. The lowest gas exchange and highest leaf mass area were recorded in plants growing at 750 m a.s.l. In the European beech growing at 1450 m a.s.l., higher vessel density, lower mean vessel diameter and higher vessel grouping index values were recorded. Overall, our results highlighted that the measured populations show a considerable phenotypic plasticity leading them to adjust anatomical and physiological traits in response to narrow ranges of environmental parameters. Despite that, the distribution of F. sylvatica seems to be limited to areas with a growing season rainfall of at least 400 mm and vapor pressure deficit (VPD) values &lt; 3 kPa, which may represent the main environmental thresholds which strongly limit the beech growth and, therefore, influence the ability of this species to cope with future environmental conditions.

Maintenance of xylem hydraulic function during winter in the woody bamboo Phyllostachys propinqua McClure.

Frost is a common environmental stress for temperate plants. Xylem embolism occurs in many overwintering plants due to freeze-thaw cycles, so coping with freeze-thaw-induced embolisms is essential for the survival of temperate plants. This study was conducted on Phyllostachys propinqua McClure, a woody bamboo species that was grown under natural frost conditions to explore its responses to winter embolisms. From autumn to the following spring, the following measurements were recorded: predawn branch and leaf embolism, branch and leaf relative water content (RWC), root pressure and soil temperature, xylem sap osmotic potential, branch and leaf electrolyte leakage (EL), branch nonstructural carbohydrate (NSC) content and leaf net photosynthetic rate. P. propinqua had a mean vessel diameter of 68.95 ±1.27 µm but did not suffer severe winter embolism, peaking around 60% in winter (January), with a distinct reduction in March when root pressure returned. Leaves had a more severe winter embolism, up to 90%. Leaf RWC was much lower in winter, and leaf EL was significantly higher than branch EL in all seasons. Root pressure remained until November when soil temperature reached 9°C, then appeared again in March when soil temperatures increased from -6°C (January) to 11°C. Xylem sap osmotic potential decreased from autumn to winter, reaching a minimum in March, and then increasing again. Soluble sugar (SS) concentration increased throughout the winter, peaked in March, and then decreased. These results suggest that (1) there is a hydraulic segmentation between the stem and leaf, which could prevent stem water loss and further embolization in winter; (2) maintenance of root pressure in early winter played an important role in reducing the effect of freeze-thaw cycles on the winter embolism; (3) the physiological process that resulted in a decrease in xylem sap osmotic potential and tissue water content, and an accumulation of SS associated with cold acclimation also aided in reducing the extent of freeze-thaw-induced embolism. All these strategies could be helpful for the maintenance of xylem hydraulic function of this bamboo species during winter.

The influence of perivascular tissue on lateral thermal expansion during bipolar vessel sealing

BackgroundLateral heat propagation has been an unavoidable effect of bipolar sealing with the risk of damage to surrounding structures. It is presently unknown whether leaving the perivascular tissue in situ may be advantageous in the sense of an isolation effect. Material and methodsTwo groups were formed from ex vivo carotid specimens. Group A (n = 10) consisted of carotid artery with the perivascular connective tissue in place (mean preparation diameter: 10.57 ± 0.16 mm) and group B (n = 10) of skeletonized carotids (mean vessel diameter: 5.21 ± 0.12 mm). All specimens were fixed on a plastic plate and mounted vertically in a holder. Sealing was performed perpendicular to the axis of the specimens. The temperature during the sealing process was recorded by a thermal camera. Group comparison was performed by a nonparametric test and significance was set at p < 0.05. ResultsMean sealing time in group A was 3.71 ± 0.37 s compared to 3.42 ± 0.37 s (p = 0.009) in group B. The maximum temperature in the middle of the jaws was significantly different. Group A had a temperature of 71.4 ± 3.9 °C and group B had a temperature of 91.4 ± 7.4 °C (p < 0.0001). RILATE risk scores (percent of necrotic zone in relation to potential area of necrosis) at both upper and lower sides of instrumental jaws were significantly different. For group A, it was 14.9 ± 1.6 at the upper side of jaws, 20.4 ± 2.63 at the lower side of jaws and for group B, it was 21.9 ± 3.5 at the upper side of jaws, 30.2 ± 6.2 at the lower side of jaws. ConclusionPerivascular connective tissue acts as an insulator with respect to lateral heat propagation. Peak temperature between instrument jaws is significantly reduced with perivascular tissue in situ. This may result in a negative impact on sealing quality.

Accuracy of IVUS-Based Machine Learning Segmentation Assessment of Coronary Artery Dimensions and Balloon Sizing

BackgroundAccurate intravascular ultrasound (IVUS) measurements are important in IVUS-guided percutaneous coronary intervention optimization by choosing the appropriate device size and confirming stent expansion. ObjectivesThe purpose of this study was to assess the accuracy of machine learning (ML) automatic segmentation of coronary artery vessel and lumen dimensions and balloon sizing. MethodsUsing expert analysis as the gold standard, ML segmentation of 60 MHz IVUS images was developed using 8,076 IVUS cross-sectional images from 234 patients, which were randomly split into training (83%) and validation (17%) data sets. The performance of ML segmentation was then evaluated using an independent test data set (437 images from 92 patients). The endpoints were the agreement rate between ML vs experts’ measurements for appropriate balloon size selection, and lumen and acute stent areas. Appropriate balloon size was determined by rounding down from the mean vessel diameter or rounding up from the mean lumen diameter to the next balloon size. The difference of lumen area ≥0.5 mm2 was considered as clinically significant. ResultsML model segmentation correlated well with experts’ segmentation for training data set with a correlation coefficient of 0.992 and 0.993 for lumen and vessel areas, respectively. The agreement rate in lumen and acute stent areas was 85.5% and 97.0%, respectively. The agreement rate for appropriate balloon size selection was 70.6% by vessel diameter only and 92.4% by adding lumen diameter. ConclusionsML model IVUS segmentation measurements were well-correlated with those of experts and selected an appropriate balloon size in more than 90% of images.

Clinical and structural outcomes of neocommissural alignment in transaxillary and transcarotid transcatheter aortic valve implantation with a self-expandable transcatheter heart valve

ObjectivesThis study analyzes neocommissural alignment and the clinical and hemodynamic outcomes after transaxillary and transcarotid implantation of the Acurate neo2 transcatheter heart valve. MethodsWe performed a retrospective, single-center analysis of early outcomes after transaxillary and transcarotid implantation of the Acurate neo2 transcatheter heart valve. Primary outcomes were neocommisural alignment, in-hospital mortality, and valve hemodynamic performance. Commissural alignment between native and transcatheter heart valves was assessed by transesophageal echocardiogram before and after the procedure. ResultsBetween October 2021 and November 2022, 40 consecutive patients were treated with the Acurate neo2 through a transaxillary or transcarotid approach. Access was achieved via the left subclavian artery in 30 cases and the left common carotid artery in 10 cases, with a mean vessel diameter of 6.7 mm. Implants most commonly used were size M (37.5%), L (35%), and S (27.5%). On the basis of transesophageal echocardiogram analysis, there was no significant difference in mean commissural orientation between native (mean, 65.1°; SD, 41.3°) and neocommissures (mean, 64°; SD, 44.1°) (P = .661). Mean commissural orientation did not significantly differ between native and neocommissures (P = .661). Optimal alignment or mild commissural misalignment was achieved in 99.5% of cases. There were no cases of severe commissural misalignment. Postprocedural mean values for peak and mean gradients were 12.7 mm Hg and 5.2 mm Hg, respectively. There were 2 cases of moderate paravalvular leak and 4 cases of mild paravalvular leak. ConclusionsThis patient-specific technique for transaxillary and transcarotid insertion of the Acurate neo2 delivery system prevents implantations with more than mild commissural misalignment and with a high device success rate.

Contrasting Responses ofTwo Grapevine Cultivars to Drought: The Role ofNon-structural Carbohydrates inXylem Hydraulic Recovery.

Xylem embolism is one of the possible outcomes of decreasing xylem pressure when plants face drought. Recent studies have proposed a role for non-structural carbohydrates (NSCs) in osmotic pressure generation, required for refilling embolized conduits. Potted cuttings of grapevine Grenache and Barbera, selected for their adaptation to different climatic conditions, were subjected to a drought stress followed by re-irrigation. Stem embolism rate and its recovery were monitored in vivo by X-ray micro-computed tomography (micro-CT). The same plants were further analyzed for xylem conduit dimension and NSC content. Both cultivars significantly decreased Ψpd in response to drought and recovered from xylem embolism after re-irrigation. However, although the mean vessel diameter was similar between the cultivars, Barbera was more prone to embolism. Surprisingly, vessel diameter was apparently reduced during recovery in this cultivar. Hydraulic recovery was linked to sugar content in both cultivars, showing a positive relationship between soluble NSCs and the degree of xylem embolism. However, when starch and sucrose concentrations were considered separately, the relationships showed cultivar-specific and contrasting trends. We showed that the two cultivars adopted different NSC-use strategies in response to drought, suggesting two possible scenarios driving conduit refilling. In Grenache, sucrose accumulation seems to be directly linked to embolism formation and possibly sustains refilling. In Barbera, maltose/maltodextrins could be involved in a conduit recovery strategy via the formation of cell-wall hydrogels, likely responsible for the reduction of conduit lumen detected by micro-CT.

Xylem structure and function of two saltbush shrub species (Atriplex) from differing microhabitats

Abstract Two formerly broadly distributed woody Atriplex species now occur as fragmented populations across a range of microhabitats in the San Joaquin Valley Desert, southern California. We hypothesized that A. lentiformis and A. polycarpa exhibit inter- and intra-specific differences in their leaf and stem structural and functional traits corresponding with differences in soil salinity and aridity. Water potential, xylem structure and function and leaf traits were compared between three populations of A. lentiformis and four populations of A. polycarpa. The two species significantly differed in their xylem traits, with A. lentiformis displaying lower xylem density, wider mean and maximum vessel diameters and higher hydraulic conductivity (Ks). They also differed in their leaf traits, such that A. lentiformis had larger leaves with higher specific leaf area (SLA) than A. polycarpa. Significant intra-specific differences occurred among leaf traits (leaf area, SLA) in A. lentiformis populations. In contrast, populations varied in their stem xylem structural traits (mean vessel wall thickness, mean vessel diameter, maximum vessel length) among A. polycarpa populations. Many of these differences were associated with soil salinity in A. lentiformis, and with minimum seasonal water potential in A. polycarpa. Overall, both saltbush species showed high intra- and inter-specific trait variation. This could be a critical consideration in understanding the evolution of these native species and has important implications for their conservation and restoration.

Microvascular Morphology MR Imaging Using Relaxation Rate Change with Gadolinium‐Based Contrast Agent in Patients with Alzheimer’s Disease

AbstractBackgroundConventional MRI techniques cannot demonstrate microvascular alterations in mild and moderate Alzheimer’s disease (AD). Thus, the diagnosis of microvascular pathology commonly relies on postmortem. The purpose of this study was to evaluate alterations of microvascular structures in patients with AD using a 3T clinical MRI system with a commercially available contrast agent.MethodEleven patients with AD and 11 non‐AD controls were included in this cross‐sectional prospective study. R2 and R2* relaxation rate changes (∆R2 and ∆R2*) before and after a Gd‐based contrast agent injection were calculated from images obtained with a multi‐echo turbo spin‐echo sequence and multi‐echo gradient‐echo sequence to obtain microvascular index maps of blood volume fraction (BVf), mean vessel diameter (mVD), vessel size index (VSI), mean vessel density (Q), and microvessel‐weighted imaging (MvWI). Two‐sample t‐test was used to compare those values between the two groups. Correlation analysis was performed to evaluate the relationship between those values and the mini‐mental state examination (MMSE) score.ResultCompared with the non‐AD group, BVf was significantly increased in the AD group at the parahippocampal gyrus (p = 0.033), gray matter area (p = 0.008), and white matter area (p = 0.010). MvWI was also significantly increased in the AD group at the hippocampus (p = 0.010), parahippocampal gyrus (p = 0.010), precuneus (p = 0.045), and globus pallidus (p = 0.008). Both mVD and VSI were only significantly decreased in the AD group at the white matter hyperintensity (WMHI) area (p = 0.045 with mVD; p = 0.033 with VSI). BVf and MvWI were significantly positively correlated with age at some areas. VSI was significantly positively correlated with MMSE at caudate (rho = 0.475/ p = 0.030) and corpus callosum (rho = 0.435/ p = 0.049).ConclusionMicrovascular index was a useful non‐invasive method to evaluate microvascular morphology alteration. The microvascular morphology of AD was manifested as vessel constriction and increasing blood volume fraction. It was associated with MMSE score.

Spatial patterns and climatic factors influence the branch xylem anatomical traits of Reaumuria soongarica in the desert region of northwestern China

The xylem is the water transport tissue of vascular plants, and its structure is closely related to the efficiency and safety of water transport. Studying how xylem anatomical traits and related functional traits vary with environmental gradients is important for understanding plant responses to environmental changes and ecological adaptation strategies. In this study, ten populations of the dominant shrub Reaumuria soongarica were selected along a west-east transect using an aridity index (AI, the ratio of annual precipitation to annual potential evapotranspiration) ranging from 0.02 to 0.09 in the desert region of northwest China. Based on AI, the sampling sites were divided into arid regions (0.05 ≤ AI < 0.2) and hyper-arid regions (AI < 0.05). Pearson correlation analysis, linear mixed models, and plant trait networks were used to analyze the spatial variation characteristics and climatic factors of 12 traits in three categories, including xylem anatomical traits, hydraulic functional traits, and mechanical strength. The results were as follows: (1) Vessel diameter contributing 95% hydraulic conductivity (D95) and wood density (WD) significantly differed between arid and hyper-arid regions, whereas the other traits were not significantly different. (2) Mean temperature of the driest quarter was one of the most important climatic factors driving the most trait variation. With the increase in AI and the precipitation of the driest quarter, D95 and the vessel grouping index (Vg) significantly increased, but not WD. The mean temperature of the driest quarter was significantly negatively correlated with D95 and WD but not significantly correlated with Vg. (3) Correlations between most traits were significant, but Vg was not significantly correlated with all other traits. Theoretical hydraulic conductivity was significantly positively correlated with the vulnerability index, indicating a trade-off between the efficiency and safety of the xylem hydraulic system. (4) Coordination among multiple traits differed at the transect and regional climate levels, and the number of edges of the trait network of hyper-arid regions was more than that of arid regions. Moreover, network analyses showed that mean vessel diameter and theoretical hydraulic conductivity are central traits in arid and hyper-arid regions, respectively, because of the number and strength of the relationships with other traits, which could be the important predictor of related hydraulic functions and associations. In conclusion, the xylem anatomical structure of R. soongarica can adapt to changing environments by different combinations of functional traits. Plant trait networks provide a novel approach for exploring the adaptation strategies of desert shrubs along environmental gradients with future climate change.