Experimental study using phantom models of cerebral aneurysms and 4D-DSA to measure blood flow on 3D-color-coded images.

Background: The current 3D-iFlow application can only measure the arrival time of contrast media through intensity values. If the flow rate could be estimated by 3D-iFlow, patient-specific hemodynamics could be determined within the scope of normal diagnostic management, eliminating the need for additional resources for blood flow rate estimation.

Objective: The aim of this study is to develop and validate a method for measuring the flow rate by data obtained from 3D-iFlow images - a prototype application in Four-dimensional digital subtraction angiography (4D-DSA).

Three-dimensional fusion imaging to assess apposition of low-profile visualized intraluminal support stent for intracranial aneurysm coiling.

Objective: To investigate on three-dimensional (3D) fusion images the apposition of low-profile visualized intraluminal support (LVIS) stents in intracranial aneurysms after treatment and assess inter-rater reliability.

Materials And Methods: Records of all patients with unruptured intracranial aneurysms who were treated with the LVIS stent were retrospectively accessed and included in this study. Two neurosurgeons evaluated the presence of malapposition between the vessel walls and the stent trunk (crescent sign) and the vessel wall and the stent edges (edge malappostion) on 3D fusion images.

Virtual coil images can optimize the visualization of the neckline of intracranial aneurysms during coil embolization: A technical note.

Background: During coil embolization of intracranial aneurysms, the aneurysmal neck needs to be evaluated because coil protrusion into the parent artery may lead to ischemic complications. However, the neck cannot always be clearly visualized due to the limitation of the angiography system and due to the structure of the aneurysm. As a visual aid, we propose a color-coded fusion imaging method that generates "virtual coil" images using preoperative three-dimensional digital subtraction angiography (3D-DSA) images.

Hemodynamic and morphological differences in cerebral aneurysms between before and after rupture.

Objective: Although it has been proposed that aneurysm morphology is different after rupture, detailed research of the morphological changes using 3D imaging acquired before and after rupture has not been conducted because of the difficulty of data collection. Similarly, hemodynamic changes due to morphological alterations after rupture have not been analyzed. The aim of this study was to investigate the changes in morphology and hemodynamics observed after aneurysm rupture.

Intraoperative Cone-Beam Computed Tomography Assessment of Spinal Pedicle Screws Placement Precision Is in Full Agreement with Postoperative Computed Tomography Assessment.

Objective: To assess agreement between pedicle screw placement evaluated on postoperative computed tomography (CT) and on intraoperative cone-beam CT (CBCT) and compare procedure characteristics when using first-generation and second-generation robotic C-arm systems in the hybrid operating room.

Methods: All patients who received pedicle screws for spinal fusion at our institution between June 2009 and September 2019 and underwent intraoperative CBCT and postoperative CT were included. The CBCT and CT images were reviewed by 2 surgeons to assess the screw placement using the Gertzbein-Robbins and the Heary classifications.

An AI-Powered Clinical Decision Support System to Predict Flares in Rheumatoid Arthritis: A Pilot Study.

Treat-to-target (T2T) is a main therapeutic strategy in rheumatology; however, patients and rheumatologists currently have little support in making the best treatment decision. Clinical decision support systems (CDSSs) could offer this support. The aim of this study was to investigate the accuracy, effectiveness, usability, and acceptance of such a CDSS-Rheuma Care Manager (RCM)-including an artificial intelligence (AI)-powered flare risk prediction tool to support the management of rheumatoid arthritis (RA).

Intraoperative cone-beam CT with metal artifact reduction for assessment of the electrode position and the intracranial structures during deep brain stimulation procedure.

Background: In deep brain stimulation (DBS) for Parkinson's disease (PD), the clinical outcome largely depends on the appropriate position of the electrode implanted in the targeted structure. In intraoperative cone-beam computed tomography (CT) performed for the evaluation of the electrode position, the metal artifact induced by the implanted electrode can prevent the precise localization of the electrode. Metal artifact reduction (MAR) techniques have been recently developed that can dramatically improve the visualization of objects by reducing metal artifacts after performing cone-beam CT.

Applying Machine Learning to Determine 25(OH)D Threshold Levels Using Data from the AMATERASU Vitamin D Supplementation Trial in Patients with Digestive Tract Cancer.

Some controversy remains on thresholds for deficiency or sufficiency of serum 25-hydroxyvitamin D (25(OH)D) levels. Moreover, 25(OH)D levels sufficient for bone health might differ from those required for cancer survival. This study aimed to explore these 25(OH)D threshold levels by applying the machine learning method of multivariable adaptive regression splines (MARS) in post hoc analyses using data from the AMATERASU trial, which randomly assigned Japanese patients with digestive tract cancer to receive vitamin D or placebo supplementation.

Extraction of patient-specific boundary conditions from 4D-DSA and their influence on CFD simulations of cerebral aneurysms.

We developed a new technique for extracting patient-specific inflow conditions, such as the pulse cycle duration and blood flow velocity, from four-dimensional digital subtraction angiography images and experimentally examined its validity. The maximum error between the values extracted by the technique and measured values was 14.3%.

Role of patient-specific blood properties in computational fluid dynamics simulation of flow diverter deployed cerebral aneurysms.

Background: Hemodynamics and their clinical outcome of cerebral aneurysms treated with flow diverter (FD) stents have thus far been investigated using computational fluid dynamics (CFD) simulations. Although human blood is characterized as a non-Newtonian patientspecific fluid, non-patient-specific blood properties (PSBP) were applied in most extant studies.

Objective: To investigate the hemodynamic effects caused by PSBPs in aneurysms treated with FD stents.

Computational fluid dynamic analysis of the initiation of cerebral aneurysms.

Objective: Relationships between aneurysm initiation and hemodynamic factors remain unclear since de novo aneurysms are rarely observed. Most previous computational fluid dynamics (CFD) studies have used artificially reproduced vessel geometries before aneurysm initiation for analysis. In this study, the authors investigated the hemodynamic factors related to aneurysm initiation by using angiographic images in patients with cerebral aneurysms taken before and after an aneurysm formation.

Development of a Virtual Stent Deployment Application to Estimate Patient-Specific Braided Stent Sizes.

A virtual stent deployment application was developed to estimate the appropriate and patient-specific size of a braided stent for patients who undergo endovascular treatment for intracranial aneurysms. Comparing between the simulated deployed and the actual stents, we evaluated the accuracy of the simulation results. Our results indicated that lengths of the virtual and actual stents matched well despite the actual stent being affected by a geometrical change of the parent artery.

Agreement between single plane and biplane derived angiographic fractional flow reserve in patients with intermediate coronary artery stenosis.

Fractional flow reserve (FFR) is often used to evaluate the physiological severity of intermediate coronary stenoses, but less-invasive assessment methods are desirable. We evaluated the feasibility of angiographic FFR (angioFFR) calculated from two projections acquired simultaneously by a biplane C-arm system and angioFFR calculated from two projections acquired independently by one plane of the same biplane C-arm system. AngioFFR was validated against FFR in terms of detection of hemodynamically relevant coronary artery stenoses.

Clinical outcomes of procedures combining endovascular embolization with a direct surgical approach in a hybrid operating room for the treatment of refractory dural arteriovenous fistulas.

Background: We reviewed the clinical outcomes of a procedure that combines endovascular embolization and a direct surgical approach in a hybrid operating room (OR) for the treatment of refractory dural arteriovenous fistulas (dAVFs).

Methods: All patients with intracranial dAVFs who underwent a procedure combining endovascular embolization and direct surgical approach with biplane angiography or a robotic C-arm system in a hybrid OR between February 2004 and June 2020 were considered. Borden grading, occlusion rate, pre-and post-operative modified Rankin Scale (mRS) scores, and complications were retrospectively investigated.

Hemodynamic and Morphologic Factors Related to Coil Compaction in Basilar Artery Tip Aneurysms.

Objective: Coil compaction is directly related to the degree of cerebral aneurysmal recanalization. The degree of recanalization (DoR) was quantified by measuring the volume vacated by coil deformation. The purpose of this study was to clarify the hemodynamic and morphologic factors associated with coil compaction.

Visualization of extracranial-intracranial bypass in moyamoya patients using intraoperative three-dimensional digital subtraction angiography with intravenous contrast injection and robotic C-arm: patient series.

Background: The authors describe a noninvasive intraoperative imaging strategy of three-dimensional (3D) digital subtraction angiography (DSA) with intravenous (IV) contrast injection, using indocyanine green (ICG) as a test bolus, during extracranial-intracranial (EC-IC) bypass surgery for moyamoya disease.

Observations: Four patients underwent EC-IC bypass surgery in a hybrid operating room. During the surgery, bypass patency was verified using ICG videoangiography and Doppler ultrasonography.

Flow Diverter Apposition in Patients with Large or Giant Intracranial Aneurysms Evaluated on Three-Dimensional Fusion Images Acquired by High-Resolution Cone-Beam Computed Tomography and Digital Subtraction Angiography.

Objective: To investigate flow diverter (FD) apposition on fused images acquired by high-resolution cone-beam computed tomography (CBCT) and 3-dimensional (3D) digital subtraction angiography.

Methods: Patients with large or giant internal carotid artery aneurysms treated with Pipeline FDs who underwent CBCT imaging at our institution between October 2016 and May 2019 were included. Two neurosurgeons measured the maximum malapposition between FDs and vessel walls on 3D fusion images of high-resolution CBCT images displaying the FD and 3D digital subtraction angiography images displaying the vessels.

4D Digital Subtraction Angiography for the Temporal Flow Visualization of Intracranial Aneurysms and Vascular Malformations.

Purpose: To assess the benefit and radiation dose of four-dimensional (4D) digital subtraction angiography (DSA) - a time resolved three-dimensional (3D) DSA application - to evaluate the flow and architecture of aneurysms and vascular malformations.

Methods: All patients with cerebrovascular disease were considered who underwent 4D-DSA at our institution between January 2015 and February 2016. For the aneurysm patients, we evaluated the image quality in terms of the visualization of contrast flow in the aneurysm on a 3-point scale (excellent, fair and poor).

BCG Vaccination and Mortality of COVID-19 across 173 Countries: An Ecological Study.

Ecological studies have suggested fewer COVID-19 morbidities and mortalities in Bacillus Calmette-Guérin (BCG)-vaccinated countries than BCG-non-vaccinated countries. However, these studies obtained data during the early phase of the pandemic and did not adjust for potential confounders, including PCR-test numbers per population (PCR-tests). Currently-more than four months after declaration of the pandemic-the BCG-hypothesis needs reexamining.

Quantitative Assessment of Thyroid Nodules Using Dual-Energy Computed Tomography: Iodine Concentration Measurement and Multiparametric Texture Analysis for Differentiating between Malignant and Benign Lesions.

Results: The 34 nodules comprised 14 benign nodules and 20 malignant nodules. Iodine content and Hounsfield unit curve slopes did not differ significantly between benign and malignant thyroid nodules ( = 0.480-0.

In-Hospital Cost Comparison of Triple-Rule-Out Computed Tomography Angiography Versus Standard of Care in Patients With Acute Chest Pain.

Purpose: The purpose of this study was to evaluate the utilization of invasive and noninvasive tests and compare cost in patients presenting with chest pain to the emergency department (ED) who underwent either triple-rule-out computed tomography angiography (TRO-CTA) or standard of care.

Materials And Methods: We performed a retrospective single-center analysis of 2156 ED patients who presented with acute chest pain with a negative initial troponin and electrocardiogram for myocardial injury. Patient cohorts matched by patient characteristics who had undergone TRO-CTA as a primary imaging test (n=1139) or standard of care without initial CTA imaging (n=1017) were included in the study.

Rupture Risk of Small Unruptured Intracranial Aneurysms in Japanese Adults.

Background and Purpose- Therapeutic decision making for small unruptured intracranial aneurysms (<10 mm) is difficult. We aimed to develop a rupture risk model for small intracranial aneurysms in Japanese adults, including clinical, morphological, and hemodynamic parameters. Methods- We analyzed 338 small unruptured aneurysms; 35 ruptured during the observation period, and 303 remained stable.

Assessing the value of coronary artery computed tomography as the first-line anatomical test for stable patients with indications for invasive angiography due to suspected coronary artery disease. Initial cost analysis in the CAT-CAD randomized trial.

Background: Clinical and safety outcomes of the strategy employing coronary computed tomography angiography (CCTA) as the first-choice imaging test have recently been demonstrated in the recently published CAT-CAD randomized, prospective, single-center study. Based on prospectively collected data in this patient population, we aimed to perform an initial cost analysis of this approach.

Methods: 120 participants of the CAT-CAD trial (age:60.