Branch Vessels Research Articles

Polystyrene nanoplastics induce developmental impairments and vasotoxicity in zebrafish (Danio rerio)

The exponential use of plastics has significantly increased environmental pollution by nanoplastics (NPs). In the aquatic environment, NPs interact and bioaccumulate in the biota, posing a potential ecotoxicological risk. The present study investigated the developmental toxicity, vasotoxicity, cytotoxicity, ROS induction, and behavioral impairments in zebrafish (Danio rerio) exposed to environmentally relevant polystyrene NPs (PS-NPs) concentrations (0.04, 34 ng L-1, and 34 μg L-1) for 144 h through multiple biomarkers response (mortality, frequency of spontaneous contractions, heart rate, and morphological changes). Furthermore, vasotoxicity (head, yolk sac, tail, and branchial vessels) was evaluated using the transgenic zebrafish tg(Fli1:eGFP). Results showed that PS-NPs interacted mainly with zebrafish chorion, gills, tail, and larvae head. PS-NPs at 34 ng L-1 and 34 μg L-1 induced neurotoxicity (decreased frequency of spontaneous contractions), cardiotoxicity (bradycardia), and morphological changes in the eyes and head, indicating that PS-NPs induce developmental impairments in zebrafish. In addition, cytotoxicity in the caudal region (34 ng L-1), ROS production, decreased mean swimming speed, and distance covered were observed in all tested concentrations. PS-NPs also induced vasotoxicity (yolk sac region) in transgenic zebrafish. Overall, the present study demonstrates the harmful effects of PS-NPs on the early developmental stages of freshwater fish, indicating their environmental risk.

Ocular features associated with mutations in ATOH7 gene overlap those with familial exudative vitreoretinopathy.

To report the ocular findings in 3 patients with a mutation in the ATOH7 gene. The clinical findings were collected from the medical records including those for magnetic resonance imaging (MRI). Genetic testing of the ATOH7 gene was performed. Three patients of two families who had poor vision since infancy were studied. The 3 patients had varying degrees of intraocular vascular proliferation associated with advanced retinal detachments as falciform retinal folds or total retinal detachments. This state is referred to as congenital retinal nonattachment. One eye of a sibling had fluorescein angiographic findings of excessive branching of the retinal vessels and fluorescent dye leakage that were consistent with those of familial exudative vitreoretinopathy (FEVR). Bilateral hypoplasia of the optic nerve was found in all three patients by MRI. Genetic analysis showed a known in-frame deletion of the ATOH7 gene in all three patients. This is the first report of a patient with a mutation in the ATOH7 gene that had typical vascular patterns of FEVR in the peripheral retina. The ocular features associated with mutations in the ATOH7 gene overlap those with FEVR at both the early and advanced stages.

Protective effects of GuanXinNing tablet (GXNT) on diabetic encephalopathy in zucker diabetic obesity (ZDF) rats

BackgroundDiabetic encephalopathy (DE) is a complication of diabetes that leads to cognitive and behavioral decline. Utilizing safe and effective complementary and alternative medications for its management is a wise choice. Previous studies have shown that GuanXinNing Tablet (GXNT), an oral preparation primarily derived from two Chinese herbs, Salvia miltiorrhiza Bge. and Ligusticum chuanxiong Hort., exerts a beneficial neuroprotective effect. In this study, we explored the protective effects of GXNT on DE in male Zucker diabetic fatty (ZDF) rats induced by a high-fat diet, aiming to ascertain its significance and potential mechanisms.MethodsZDF rats were induced to develop type 2 diabetes (T2DM) with DE by a high-fat diet and treated with GXNT for 8 weeks until they were 20 weeks old. Throughout the experiment, the animals’ vital parameters, such as body weight, were continuously monitored. Cognitive function was evaluated using the Y maze test. Biochemical kits were employed to analyze blood glucose, lipids, and vascular endothelial-related factors. Cerebrovascular lesions were assessed using magnetic resonance angiography (MRA) imaging. Brain lesions were evaluated using hematoxylin and eosin (H&E) staining and ultrastructure observation. IgG and albumin (ALB) leakage were detected using immunofluorescence.ResultsGXNT demonstrated an enhancement in the overall well-being of the animals. It notably improved cognitive and behavioral abilities, as demonstrated by extended retention time in the novel heterogeneous arm during the Y-maze test. GXNT effectively regulated glucose and lipid metabolism, reducing fasting and postprandial blood glucose, glycated hemoglobin (HbA1c), and total cholesterol (TC) levels. Additionally, it exhibited a protective effect on the vascular endothelium by reducing the serum TXB2/PGI2 ratio while elevating NO and PGI2 levels. Moreover, GXNT ameliorated stenosis and occlusion in cerebral vessel branches, increased the number of microvessels and neurons around the hippocampus, and improved microvascular occlusion in the cerebral cortex, along with addressing perivascular cell abnormalities. Immunofluorescence staining showed a decrease in the fluorescence intensity of IgG and ALB in the cerebral cortex.ConclusionsGXNT demonstrated a highly satisfactory protective effect on DE in ZDF rats. Its mechanism of action could be based on the regulation of glucolipid metabolism and its protective effect on the vascular endothelium.

Dynamic evaluation of unruptured intracranial aneurysms by 4D-CT angiography: comparison with digital subtraction angiography (DSA) and surgical findings

BackgroundThis study was to prospectively investigate the feasibility of four-dimensional computed tomography angiography (4D-CTA) with electrocardiogram-gated (ECG) reconstruction for preoperative evaluation of morphological parameters, and compared with digital subtraction angiography (DSA). We also aimed to detect pulsation in unruptured intracranial aneurysms (UIAs) by using 4D-CTA, as a potential predicting factor of growth or rupture.Materials64 patients with 64 UIAs underwent ECG-gated dynamic 4D-CTA imaging before treatment, of which 46 patients additionally underwent DSA. Original scanning data were reconstructed to produce 20 data sets of cardiac cycles with 5%-time intervals. The extent of agreement on UIAs morphological features assessed with 4D-CTA and DSA was estimated using the k coefficient of the Kappa test. The radiation doses were also calculated and compared between 4D-CTA and DSA. In the aneurysmal surgically treated in our institution, we were able to compare the surgical findings of the aneurysm wall with 4D-CTA images. We performed long-term follow-up on untreated patients.ResultsThe morphological characteristics detected by 4D-CTA and DSA were consistent in aneurysm location (k = 1.0), shape (k = 0.76), maximum diameter (k = 0.94), aneurysm neck (k = 0.79) and proximity to parent and branch vessels (k = 0.85). 4D-CTA required lower radiation doses (0.32 ± 0.11 mSv) than DSA (0.84 ± 0.37 mSv, P < 0.001). Pulsation was detected in 26 of the 64 unruptured aneurysms, and all underwent neurosurgical clipping or interventional embolization. In aneurysms surgically treated in our hospital, we observed a significant correlation between 4D-CTA findings and surgical evaluation of the aneurysmal wall, in particular the irregular pulsations detected on 4D-CTA have demonstrated to correspond to dark-reddish thinner wall at surgery.ConclusionsIn this proof-of-concept study, 4D-CTA provided real-time, non-invasive preoperative assessments of UIAs comparable to DSA. Moreover, optimal correlation between the irregular pulsation detected by 4D-CTA and the surgical findings support a possible role of this technique to identify aneurysms with a higher risk of rupture.

Comparison of laparoscopic lateral lymph node dissection for rectal cancer with and without routine resection of the visceral branches of internal iliac artery.

This study aimed to explore the safety and feasibility of the modified lateral lymph node dissection (LLND) with routine resection of the visceral branches of internal iliac vessels (IIVs) for mid-low-lying rectal cancer. Consecutive patients undergoing LLND for rectal cancer were divided into the routine visceral branches of the IIVs resection group (RVR group) and the NRVR group (without routine resection). The main outcomes were postoperative complications and the number of lateral lymph nodes harvested. From 2012 to 2021, a total of 75 and 57 patients were included in the RVR and NRVR group, respectively. The operative time was reduced in the RVR group (p = 0.020). No significant difference was observed between the two groups for the incidence of total, major, or minor postoperative complications. Pathologically confirmed LLNM were 24 (32%) patients in the RVR group and 12 (21.1%) in the NRVR group (p = 0.162). The number of lateral lymph nodes harvested had no significant difference between two groups (11 vs. 12, p = 0.329). LLND with routine resection of visceral branches of IIVs is safe and feasible, which brings no major complication or long-term urinary disorder.

AVDNet: Joint coronary artery and vein segmentation with topological consistency

Coronary CT angiography (CCTA) is an effective and non-invasive method for coronary artery disease diagnosis. Extracting an accurate coronary artery tree from CCTA image is essential for centerline extraction, plaque detection, and stenosis quantification. In practice, data quality varies. Sometimes, the arteries and veins have similar intensities and locate closely, which may confuse segmentation algorithms, even deep learning based ones, to obtain accurate arteries. However, it is not always feasible to re-scan the patient for better image quality. In this paper, we propose an artery and vein disentanglement network (AVDNet) for robust and accurate segmentation by incorporating the coronary vein into the segmentation task. This is the first work to segment coronary artery and vein at the same time. The AVDNet consists of an image based vessel recognition network (IVRN) and a topology based vessel refinement network (TVRN). IVRN learns to segment the arteries and veins, while TVRN learns to correct the segmentation errors based on topology consistency. We also design a novel inverse distance weighted dice (IDD) loss function to recover more thin vessel branches and preserve the vascular boundaries. Extensive experiments are conducted on a multi-center dataset of 700 patients. Quantitative and qualitative results demonstrate the effectiveness of the proposed method by comparing it with state-of-the-art methods and different variants. Prediction results of the AVDNet on the Automated Segmentation of Coronary Artery Challenge dataset are avaliabel at https://github.com/WennyJJ/Coronary-Artery-Vein-Segmentation for follow-up research.

Mapping the human parafoveal vascular network to understand flow variability in capillaries.

Capillary flow is known to be non-homogenous between vessels and variable over time, for reasons that are poorly understood. The local properties of individual vessels have been shown to have limited explanatory power in this regard. This exploratory study investigates the association of network-level properties such as vessel depth, branch order, and distance from the feeding arteriole with capillary flow. Detailed network connectivity analysis was undertaken in 3 healthy young subjects using flood-illuminated adaptive optics retinal imaging, with axial depth of vessels determined via optical coherence tomography angiography. Forty-one out of 70 vessels studied were of terminal capillary type, i.e. fed from an arterial junction and drained by a venous junction. Approximately half of vessel junctions were amenable to fitting with a model of relative branch diameters, with only a few adhering to Murray's Law. A key parameter of the model (the junction exponent) was found to be inversely related to the average velocity (r = -0.59, p = 0.015) and trough velocity (r = -0.67, p = 0.004) in downstream vessels. Aspects of cellular flow, such as the minimum velocity, were also moderately correlated (r = 0.46, p = 0.009) with distance to the upstream feeding arteriole. Overall, this study shows that capillary network topology contributes significantly to the flow variability in retinal capillaries in human eyes. Understanding the heterogeneity in capillary flow is an important first step before pathological flow states can be properly understood. These results show that flow within capillary vessels is not affected by vessel depths but significantly influenced by the upstream feeder distance as well as the downstream vessel junction exponents, but there remains much to be uncovered regarding healthy capillary flow.

Arterial Bypass in the Treatment of Complex Middle Cerebral Artery Aneurysms: Lessons Learned from Forty Patients

Complex middle cerebral artery (MCA) aneurysms incorporating parent or branching vessels are often not amenable to standard microsurgical clipping or endovascular embolization treatments. We aim to discuss the treatment of such aneurysms via a combination of surgical revascularization and aneurysm exclusion based on our institutional experience. Thirty-four patients with complex MCA aneurysms were treated with bypass and aneurysm occlusion, 5 with surgical clipping or wrapping only, and 1 with aneurysm excision and primary reanastomosis. Bypasses included superficial temporal artery (STA)-MCA, double-barrel STA-MCA, occipital artery-MCA, and external carotid artery-MCA. After bypass, aneurysms were treated by surgical clipping, Hunterian ligation, trapping, or coil embolization. The average age at diagnosis was 46 years. Of the aneurysms, 67% were large and most involved the MCA bifurcation. Most bypasses performed were STA-MCA bypasses, 12 of which were double-barrel. There were 2wound-healing complications. All but 2 of the aneurysms treated showed complete occlusion at the last follow-up. There were 3 hemorrhagic complications, 3 graft thromboses, and 4 ischemic insults. The mean follow-up was 73months. Of patients, 83% reported stable or improved symptoms from presentation and 73% reported a functional status (Glasgow Outcome Scale score 4 or 5) at the latest available follow-up. Cerebral revascularization by bypass followed by aneurysm or parent artery occlusion is an effective treatment option for complex MCA aneurysms that cannot be safely treated by standard microsurgical or endovascular techniques. Double-barrel bypass consisting of 2 STA branches to 2 MCA branches yields adequate flow replacement in most cases.

A 3D-printed phantom for quality-controlled reproducibility measurements of arterial spin labeled perfusion.

To develop a portable MR perfusion phantom for quality-controlled assessment and reproducibility of arterial spin labeled (ASL) perfusion measurement. A 3D-printed perfusion phantom was developed that mimics the branching of arterial vessels, capillaries, and a chamber containing cellulose sponge representing tissue characteristics. A peristaltic pump circulated distilled water through the phantom, and was first evaluated at 300, 400, and 500 mL/min. Longitudinal reproducibility of perfusion was performed using 2D pseudo-continuous ASL at 20 post-label delays (PLDs, ranging between 0.2 and 7.8 s at 0.4-s intervals) over a period of 16 weeks, with three repetitions each week. Multi-PLD data were fitted into a general kinetic model for perfusion quantification (f) and arterial transit time (ATT). Intraclass correlation coefficient was used to assess intersession reproducibility. MR perfusion signals acquired in the 3D-printed perfusion phantom agreed well with the experimental conditions, with progressively increasing signal intensities and decreasing ATT for pump flow rates from 300 to 500 mL/min. The perfusion signal at 400 mL/min and the general kinetic model-derived f and ATT maps were similar across all PLDs for both intrasession and intersession reproducibility. Across all 48 experimental time points, the average f was 75.55 ± 3.83 × 10-3 mL/mL/s, the corresponding ATT was 2.10 ± 0.20 s, and the T1 was 1.84 ± 0.102 s. Intraclass correlation coefficient was 0.92 (95% confidence interval 0.83-0.97) for f, 0.96 (0.91-0.99) for ATT, and 0.94 (0.88-0.98) for T1 , demonstrating excellent reproducibility. A simple, portable 3D-printed perfusion phantom with excellent reproducibility of 2D pseudo-continuous ASL measurements was demonstrated that can serve for quality-controlled and reliable measurements of ASL perfusion.

Improved precise guidewire delivery of a cardiovascular interventional surgery robot based on admittance control.

The development of cardiovascular interventional surgery robots can realize master-slave interventional operations, which will effectively solve the problem of surgeons being injured by X-ray radiation. The delivery accuracy and safety of interventional instruments such as guidewire are the most important issues in the development of robotic systems. Most of the current control methods are position control or force feedback control, which cannot take into account delivery accuracy and safety. A cardiovascular interventional surgery robotic system integrated force sensors is developed. A novel force/position controller, which includes a radial basis function neural networks-based inner loop position controller and a force-based admittance outer loop controller, is proposed. Furthermore, a series of simulations and vascular model experiments are carried out to demonstrate the feasibility and accuracy of the proposed controller. The designed cardiovascular interventional robot is flexible to enter the target vessel branch. Experimental results indicate that the proposed controller can effectively improve the delivery accuracy of the guidewire and reduce the contact force with the vessel wall. The proposed controller based on radial basis function neural network and admittance control is effective in improving delivery accuracy and reducing contact force. The algorithm needs to be further validated in vivo experiments.

Utilizing indocyanine green video angiography to bridge intracranial aneurysm treatment gaps in low- and middle-income countries: a mini-review.

Intracranial aneurysms, affecting 2%-5% of the population, pose a significant challenge to neurosurgeons due to their potential to cause subarachnoid haemorrhage and high mortality rates. Intraoperative angiography is necessary for effective surgical planning and indocyanine green video angiography (ICG-VA) has emerged as a useful tool for real-time visualization of aneurysmal blood flow, aiding in better planning for potential blood flow and detection of aneurysm remnants. This mini narrative review explores the application of ICG-VA in intracranial aneurysm surgery. Compared with conventional dye-based angiography, ICG-VA is safer, more effective and more cost-effective. It can assess haemodynamic parameters, cerebral flow during temporary artery occlusion, completeness of clipping and patency of branch vessels. However, implementing ICG-VA in low- and middle-income countries presents challenges such as financial constraints, limited access to training and expertise, patient selection and consent issues. Addressing these obstacles requires capacity-building, training programmes for neurosurgeons and multidisciplinary teams, technology transfer, equipment donations, public-private partnerships, continued research and development, reducing conventional dye usage, reducing ICG wastage, exploring mechanisms to reuse ICG dyes and advocating for increased government funding and healthcare budgets.

Antibacterial and angiogenic potential of iron oxide nanoparticles-stabilized acrylate-based scaffolds for bone tissue engineering applications

Pickering emulsion polymerization, stabilized by inorganic nanoparticles such as iron oxide nanoparticles (IONPs), can be used to fabricate scaffolds with the desired porosity and pore size. These nanoparticles create stable emulsions that can be processed under harsh polymerization conditions. IONPs, apart from serving as an emulsifier, impart beneficial bioactivities such as antibacterial and pro-angiogenic activity. Here, we coated IONPs with three different weights of oleic acid (5.0 g, 7.5 g, and 10.0 g) to synthesize oleic acid-IONPs (OA-IONPs) that possess the desired hydrophobicity (contact angle > 100°). Next, glycidyl methacrylate and trimethylolpropane triacrylate were polymerized using the Pickering emulsion polymerization technique stabilized by the OA-IONPs. The physicochemical properties of the resulting porous scaffolds were thoroughly characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), and a universal testing machine (UTM). The SEM images confirmed the formation of a porous scaffold. The IONPs content, measured using inductively coupled plasma mass spectrometry (ICP-MS), was in the range of 22–26 µg/mg of the scaffold. The mechanical strengths of the scaffolds were in the range of cancellous bone. The degradation profile of the scaffolds varied between 29% and 41% degradation over 30 days. In vitro cytotoxicity studies conducted using the fibroblast (L929) and osteosarcoma (MG-63) cell lines proved that these scaffolds were non-toxic. SEM images showed that the MG-63 cells adhered firmly to the scaffolds and exhibited a well-spread morphology. The antibacterial activity was confirmed by percentage inhibition studies, SEM analysis of bacterial membrane distortion, and reactive oxygen species (ROS) generation in the bacteria. Chick chorioallantoic membrane assay showed that the total vessel length and branch points were significantly increased in the presence of the scaffolds. These results confirm the pro-angiogenic potential of the fabricated scaffolds. The physicochemical, mechanical, and biological properties of the material suggest that the developed scaffolds would be suitable for bone tissue engineering applications.

Successful Outcome of Pregnancy in two Cases of Takayasu Arteritis

Introduction : Takayasu arteritis is a vasculitis of unknown cause. It is a disease of involvement of vessels of branches of the aortic arch. It can affect women of reproductive age and may present with pregnancy. Pregnancy may have a favorable outcome if diagnosed and appropriately managed from the onset of the disease and enter pregnancy in the remission phase and with medication. But, if it is diagnosed for the first time during pregnancy outcome might be worse. Case reports: Here presented two case reports of diagnosed Takahashi Arteritis with term pregnancy; who entered pregnancy in remission phase and on medication. The prior preparation leads the pregnancy to a successful outcome without any residual effect on feto-maternal health. Conclusion: Early diagnosis of the disease and proper management of the progress of the disease by intervention is essential for a good prognosis. A close follow-up and multidisciplinary approach during pregnancy make pregnancy a safer journey for a woman with Takahashi Arteritis. Bangladesh J Obstet Gynaecol, 2022; Vol. 37(1): 63-67

Deferred Stenting for Side Branch in STEMI Patients Presented by Bifurcation Culprit Lesion

Abstract Background True bifurcation lesions are challenging in some special populations like patients with heavily calcified vessels, unprotected left main, and thrombus-containing lesions. Multiple inflations are known to increase the incidence of no-reflow/slow-flow (NR/SL) during primary PCI. The ideal bifurcation stenting strategy during primary PCI is still obscure. Some studies have shown some benefits for deferred stenting in primary PCI but still this area needs more evidence. In our study, we compared deferred stenting for the side branch during primary PCI versus the complete bifurcation stenting strategy during primary PCI. Methods This is prospective observational study included patients who presented with STEMI due to true bifurcation culprit lesion amenable for two stents technique. Group one included patients with provisional stenting and deferred side branch stenting before hospital discharge. Group two included patients with complete two stents bifurcation technique during primary PCI. The technique used was according to operator discretion while patients with immediate indications for two stents strategy during the primary setting were excluded from our study. The primary outcome was MACE till hospital discharge. Secondary outcomes included angiographic outcomes by the end of the bifurcation technique. Results A total of 60 patients met our inclusion criteria, mean age (58.69±9.61), 31.2% women. Twenty-six patients received deferred stenting for side branch, and 34 received complete two stents bifurcation strategy at the primary PCI setting. MACE to hospital discharge was lower in the deferred stenting group without significant difference (21.62% vs 23.64%, P&amp;gt;0.01] compared with the two-stenting approach during primary PCI. Group I (deferred stenting) had significantly superior angiographic outcomes than group II. As regards TIMI II-III flow, 86.2% of patients achieved it in both main vessel and side branch versus 51.1% in group II, CTFC was 8.1 versus 9.6, and in group I, 78% of patients achieved TMPG II-III, compared to 56.7% in group II. Conclusion Deferred stenting for side branch in primary PCI achieved superior angiographic outcomes in the treatment of true bifurcation lesions. However, there was no significant difference in MACE between both strategies.

Specific features of human placenta anatomy in pregnancy achieved by in vitro fertilization

Aim to evaluate the qualitative and quantitative morphological characteristics of placentas of pregnant women after in vitro fertilization (IVF) registered in the prenatal period and after birth.&#x0D; Material and methods. The retrospective study of medical records of pregnant and puerperia women focused on the chorion and placenta parameters registered by ultrasound examinations in the I, II, III trimesters. The patients' inclusion criteria were singleton pregnancy and birth at 37-41 weeks' gestation. The types of assisted reproductive technologies and delivery were not specified in this study. The patients were divided into 2 groups according to their age: 1 Group I period of adulthood, 2 Group II period of adulthood. The postpartum placenta morphometry included registration of shape, diameter, weight, thickness of the placenta, the place of attachment and length of the umbilical cord, the type of vessels branching.&#x0D; Results. 1. The ultrasound characteristics of the placenta anatomy during pregnancy achieved by IVF are generally normal and do not have specific features.&#x0D; &#x0D; The pathological location of the chorion in the uterine cavity in the first trimester of pregnancy is characterized by a risk factor the older age group.&#x0D; The weight of the placenta during full-term pregnancy after in vitro fertilization is higher than normal, its average area is larger due to a decrease in thickness.&#x0D; A large proportion of pathological (sheath) attachment of the umbilical cord can lead to more frequent complications of pregnancy acute placental insufficiency.

In situ laser fenestration of aortic septum to bridge false and true lumen during endovascular repair of aortic dissection

Fenestration of the septum between the true and false lumen might be necessary after aortic dissection. We report the technical aspects of in situ laser fenestration of the aortic dissection septum. Two illustrative cases are provided: a 56-year-old man with false lumen deployment of a frozen elephant trunk graft, and a 67-year-old man who underwent fenestrated endovascular aortic repair with a target branch vessel off the false lumen. In both cases, the septum was crossed using in situ laser fenestration. This technique is a precise option to enable passage between true and false lumens during endovascular repair of an aortic dissection.

Spatiotemporal frequency domain analysis for blood velocity measurement during embolization procedures.

Currently, determining procedural endpoints and treatment efficacy of vascular interventions is largely qualitative and relies on subjective visual assessment of digital subtraction angiography (DSA) images leading to large interobserver variabilities and poor reproducibility. Quantitative metrics such as the residual blood velocity in embolized vessel branches could help establish objective and reproducible endpoints. Recently, velocity quantification techniques based on a contrast enhanced X-ray sequence such as qDSA and 4D DSA have been proposed. These techniques must be robust, and, to avoid radiation dose concerns, they should be compatible with low dose per frame imageacquisition. To develop and evaluate a technique for robust blood velocity quantification from low dose contrast enhanced X-ray image sequences that leverages the oscillating signal created by pulsatile bloodflow. The proposed spatiotemporal frequency domain (STF) approach quantifies velocities from time attenuation maps (TAMs) representing the oscillating signal over time for all points along a vessel centerline. Due to the time it takes a contrast bolus to travel along the vessel centerline, the resulting TAM resembles a sheared sine wave. The shear angle is related to the velocity and can be determined in the spatiotemporal frequency domain after applying the 2D Fourier transform to the TAM. The approach was evaluated in a straight tube phantom using three different radiation dose levels and compared to ultrasound transit-time-based measurements. The STF velocity results were also compared to previously published approaches for the measurement of blood velocity from contrast enhanced X-ray sequences including shifted least squared (SLS) and phase shift (PHS). Additionally, an in vivo porcine study (n = 8) was performed where increasing amounts of embolic particles were injected into a hepatic or splenic artery with intermittent velocity measurements after each injection to monitor the resulting reduction invelocity. At the lowest evaluated dose level (average air kerma rate 1.3 mGy/s at the interventional reference point), the Pearson correlation between ultrasound and STF velocity measurements was . This was significantly higher ( ) than corresponding correlation results between ultrasound and the previously published SLS and PHS approaches ( and , respectively). In the in vivo study, a reduction in velocity was observed in of cases after injection of 1 mL, after 3 mL, and after 4 mL of embolicparticles. The results show good agreement of the spatiotemporal frequency domain approach with ultrasound even in low dose per frame image sequences. Additionally, the in vivo study demonstrates the ability to monitor the physiological changes due to embolization. This could provide quantitative metrics during vascular procedures to establish objective and reproducibleendpoints.

Sensitivity of hostile hemodynamics to aneurysm geometry via unsupervised shape interpolation

Background and ObjectiveVessel geometry and hemodynamics are intrinsically linked, whereby geometry determines hemodynamics, and hemodynamics influence vascular remodeling. Both have been used for testing clinical outcomes, but geometry/morphology generally has less uncertainty than hemodynamics derived from medical image-based computational fluid dynamics (CFD). To provide clinical utility, CFD-based hemodynamic parameters must be robust to modeling errors and/or uncertainties, but must also provide useful information not more-easily extracted from shape alone. The objective of this study was to methodically assess the response of hemodynamic parameters to gradual changes in shape created using an unsupervised 3D shape interpolation method. MethodsWe trained the neural network NeuroMorph on 3 patient-derived intracranial aneurysm surfaces (labelled A, B, C), and then generated 3 distinct morph sequences (A→B, B→C, C→A) each containing 10 interpolated surfaces. From high-fidelity CFD simulation of these, we calculated a variety of common reduced hemodynamic parameters, including many previously associated with aneurysm rupture, and analyzed their responses to changes in shape, and their correlations. ResultsThe interpolated surfaces demonstrate complex, gradual changes in branch angles, vessel diameters, and aneurysm morphology. CFD simulation showed gradual changes in aneurysm jetting characteristics and wall-shear stress (WSS) patterns, but demonstrated a range of responses from the reduced hemodynamic parameters. Spatially and temporally averaged parameters including time-averaged WSS, time-averaged velocity, and low-shear area (LSA) showed low variation across all morph sequences, while parameters of flow complexity such as oscillatory shear, spectral broadening, and spectral bandedness indices showed high variation between slightly-altered neighboring surfaces. Correlation analysis revealed a great deal of mutual information with easier-to-measure shape-based parameters. ConclusionsIn the absence of large clinical datasets, unsupervised shape interpolation provides an ideal laboratory for exploring the delicate balance between robustness and sensitivity of nominal hemodynamic predictors of aneurysm rupture. Parameters like time-averaged WSS and LSA that are highly “robust” may, as a result, be effectively redundant to morphological predictors, whereas more sensitive parameters may be too uncertain for practical clinical use. Understanding these sensitivities may help identify parameters that are capable of providing added value to rupture risk assessment.

Enabling supra-aortic vessels inclusion in statistical shape models of the aorta: a novel non-rigid registration method.

Statistical Shape Models (SSMs) are well-established tools for assessing the variability of 3D geometry and for broadening a limited set of shapes. They are widely used in medical imaging due to their ability to model complex geometries and their high efficiency as generative models. The principal step behind these techniques is a registration phase, which, in the case of complex geometries, can be a critical issue due to the correspondence problem, as it necessitates the development of correspondence mapping between shapes. The thoracic aorta, with its high level of morphological complexity, poses a multi-scale deformation problem due to the presence of several branch vessels with varying diameters. Moreover, branch vessels exhibit significant variability in shape, making the correspondence optimization even more challenging. Consequently, existing studies have focused on developing SSMs based only on the main body of the aorta, excluding the supra-aortic vessels from the analysis. In this work, we present a novel non-rigid registration algorithm based on optimizing a differentiable distance function through a modified gradient descent approach. This strategy enables the inclusion of custom, domain-specific constraints in the objective function, which act as landmarks during the registration phase. The algorithm's registration performance was tested and compared to an alternative Statistical Shape modeling framework, and subsequently used for the development of a comprehensive SSM of the thoracic aorta, including the supra-aortic vessels. The developed SSM was further evaluated against the alternative framework in terms of generalisation, specificity, and compactness to assess its effectiveness.

Transanal Minimally Invasive Surgical Approach to Total Pelvic Exenteration.

Total pelvic exenteration, a surgical procedure for patients with highly advanced primary and recurrent rectal cancer, is technically demanding. We report the utility of a transanal minimally invasive surgical approach to total pelvic exenteration. A 2-team approach with a laparoscopic transabdominal approach and transanal minimally invasive surgery was adopted. During the transabdominal approach in the pelvis, dissection was performed to remove the pelvic organs and visceral branches of the internal iliac vessels. The dissection goal via the transabdominal approach is the levator ani. During the transperineal approach, dissection is performed along the levator ani, and the tendinous arch of the levator ani is penetrated at the lateral side to achieve rendezvous between the 2 approaches. The levator ani is then dissected circumferentially, with identification of the internal pudendal vessels passing through the levator ani at the 4 o'clock and 8 o'clock positions, known as Alcock's canal. The anterior wall of Alcock's canal is formed by the coccygeus muscle and sacrospinous ligament, which are dissected by the transperineal approach to open Alcock's canal, thus obtaining a clear view of the internal pudendal vessels. On the anterior side, the urethra is divided with a laparoscopic linear stapler via the transperineal approach. Eight patients with rectal cancer underwent this procedure. The median (range) blood loss was 200 (120-1520) mL and operating time was 467 (321-833) minutes. Reoperation was performed in 1 internal hernia case; however, there were no mortalities, and there were no cases with severe complications or conversion to open surgery. When performing total pelvic exenteration, transanal minimally invasive surgery offers direct visualization behind the tumor from the anal side and shows the deep pelvic structures, including the retroperitoneal space of the pelvic sidewall.