Evolution of Three-Dimensional Computed Tomography Imaging in Thoracic Surgery.

Radiologic reconstruction technology allows the wide use of three-dimensional (3D) computed tomography (CT) images in thoracic surgery. A minimally invasive surgery has become one of the standard therapies in thoracic surgery, and therefore, the need for preoperative and intraoperative simulations has increased. Three-dimensional CT images have been extensively used, and various types of software have been developed to reconstruct 3D-CT images for surgical simulation worldwide. Several software types have been commercialized and widely used by not only radiologists and technicians, but also thoracic surgeons. Three-dimensional CT images are helpful surgical guides; however, in almost all cases, they provide only static images, different from the intraoperative views. Lungs are soft and variable organs that can easily change shape by intraoperative inflation/deflation and surgical procedures. To address this issue, we have developed a novel software called the Resection Process Map (RPM), which creates variable virtual 3D images. Herein, we introduce the RPM and its development by tracking the history of 3D CT imaging in thoracic surgery. The RPM could help develop a real-time and accurate surgical navigation system for thoracic surgery.

Three-Dimensional Bowing Measurement of Distal Femur at Actual Size and Clinical Implications of Total Knee Arthroplasty.

Background and Objectives: To assess femoral shaft bowing (FSB) in coronal and sagittal planes and introduce the clinical implications of total knee arthroplasty (TKA) by analyzing a three-dimensional (3D) model with virtual implantation of the femoral component. Materials and Methods: Sixty-eight patients (average age: 69.1 years) underwent 3D model reconstruction of medullary canals using computed tomography (CT) data imported into Mimics® software (version 21.0). A mechanical axis (MA) line was drawn from the midportion of the femoral head to the center of the intercondylar notch. Proximal/distal straight centerlines (length, 60 mm; diameter, 1 mm) were placed in the medullary canal's center. Acute angles between these centerlines were measured to assess lateral and anterior bowing. The acute angle between the distal centerline and MA line was measured for distal coronal and sagittal alignment in both anteroposterior (AP) and lateral views. The diameter of curve (DOC) along the posterior border of the medulla was measured. Results: The mean lateral bowing in the AP view was 3.71°, and the mean anterior bowing in the lateral view was 11.82°. The average DOC of the medullary canal was 1501.68 mm. The average distal coronal alignment of all femurs was 6.40°, while the distal sagittal alignment was 2.66°. Overall, 22 femurs had coronal bowing, 42 had sagittal bowing, and 15 had both. Conclusions: In Asian populations, FSB can occur in coronal, sagittal, or both planes. Increased anterolateral FSB may lead to cortical abutment in the sagittal plane, despite limited space in the coronal plane. During TKA, distal coronal alignment guides the distal femoral valgus cut angle, whereas distal sagittal alignment aids in predicting femoral component positioning to avoid anterior notching. However, osteotomies along the anterior cortical bone intended to prevent notching may result in outliers due to differences between the distal sagittal alignment and the distal anterior cortical axis.

A three-dimensional spring-loaded inverted pendulum walking model considering human movement speed and frequency.

The spring-loaded inverted pendulum (SLIP) model is an effective model to capture the essential dynamics during human walking and/or running. However, most of the existing three-dimensional (3D) SLIP model does not explicitly account for human movement speed and frequency. To address this knowledge gap, this paper develops a new SLIP model, which includes a roller foot, massless spring, and concentrated mass. The governing equations-of-motion for the SLIP model during its double support phase are derived. It is noted that in the current formulation, the motion of the roller foot is prescribed; therefore, only the equations for the concentrated mass need to be solved. To yield model parameters leading to a periodic walking gait, a constrained optimization problem is formulated and solved using a gradient-based approach with a global search strategy. The optimization results show that when the attack angle ranges from 68° to 74°, the 3D SLIP model can yield a periodic walking gait with walking speeds varying from 0.5 to 2.0 m s-1. The predicted human walking data are also compared with published experimental data, showing reasonable accuracy.

Morphology of the dysplastic hip and the relationship with sex and acetabular version.

The dysplastic hip is characterized by incomplete coverage of the femoral head, resulting in increased risk of early osteoarthritis. The morphological variation of the hip joint is diverse and clear differences exist between females and males. The aim of this observational study was therefore to investigate the relationship between the morphology of the hip, sex, and hip dysplasia using a three-dimensional model. Statistical shape models of the combined femur and pelvic bones were created from bilateral hips of 75 patients. Using manual angle measurements and regression analysis, the characteristic shape differences associated with sex and hip dysplasia were determined. The model showed clear differences associated with sex and hip dysplasia. We found that the acetabular anteversion in females was significantly higher (p < 0.0001) than in males while no significant difference in acetabular anteversion was found between normal and dysplastic hips (p = 0.11). The model showed that decreased acetabular anteversion resulted in the appearance of the cross-over sign and the prominent ischial spine sign commonly associated with retroversion. Sex could be predicted with an area under the curve of 0.99 and hip dysplasia could be predicted with an area under the curve of ≥0.73. Our findings suggest that retroversion is a result of decreased anteversion of the acetabulum and is primarily associated with sex. This finding should be taken into account during the reorientation of the acetabulum in the surgical treatment of hip dysplasia.

Canine Upper Digestive Tract 3D Model: Assessing Its Utility for Anatomy and Upper Endoscopy Learning.

A teaching strategy using 3D-printed models of the canine upper digestive tract (UDT) for anatomy demonstration and upper endoscopy instruction was evaluated. The canine UDT (esophagus-stomach-duodenum) was scanned and 3D-printed molds were manufactured using silicone casting. First-year students were introduced to these 3D models in practical sessions alongside real specimens. Simultaneously, fifth-year students were trained in endoscope handling and anatomical recognition using 3D specimens. Both groups completed an anonymous survey. Results showed that overall, first-year (n = 93) and fifth-year (n = 45) students agreed or strongly agreed that the 3D-printed model was effective for learning purposes. In summary, first-year students highlighted an improved understanding of size, volume, topography, and easier manipulation of the 3D model compared to fresh specimens. Fifth-year students were more enthusiastic, finding the 3D model valuable for spatial vision and clinical training. While both groups were against completely replacing the natural UDT with the 3D model, first-year students were more hesitant. These findings suggest that the 3D model of the canine UDT is an effective tool for hands-on training in clinical endoscopy and a valuable, albeit complementary, resource for teaching anatomy and topography.

Development of a 3D Vascular Network Visualization Platform for One-Dimensional Hemodynamic Simulation.

Recent advancements in computational performance and medical simulation technology have made significant strides, particularly in predictive diagnosis. This study focuses on the blood flow simulation reduced-order models, which provide swift and cost-effective solutions for complex vascular systems, positioning them as practical alternatives to 3D simulations in resource-limited medical settings. The paper introduces a visualization platform for patient-specific and image-based 1D-0D simulations. This platform covers the entire workflow, from modeling to dynamic 3D visualization of simulation results. Two case studies on, respectively, carotid stenosis and arterial remodeling demonstrate its utility in blood flow simulation applications.

Association between 3D membranous urethral parameters and urinary continence recovery after RARP.

OBJECTIVES: To evaluate whether the urinary continence (UC) recovery after robotic-assisted radical prostatectomy (RARP) relates to the membranous urethral length (MUL) and the membranous urethral complex volume (MUV). MATERIALS AND METHODS: 120 patients who underwent RARP were enrolled according to the different times of UC recovery and examined using prostate magnetic resonance imaging (MRI) before surgery. The membranous urethral (MU) parameters were measured using the three-Dimensional (3D) model reconstructed by holographic technology, such as total MUV (tMUV), exposed MUV (eMUV), full MUL (fMUL) and exposed MUL (eMUL). Statistical software SPSS 26.0 was used to analyze the data and compare the MU parameters and baseline data in different groups. RESULTS: Patients with larger tMUV (p = 0.038), eMUV (p = 0.003), longer fMUL (p = 0.025), eMUL (p = 0.044) had better UC after removal of the catheter, and eMUV (OR = 1.002, 95%CI = 1.001-1.004, p = 0.004) was a predictor; the patients with younger age (p = 0.021), lower VPSS score (p = 0.004) and larger eMUV (p = 0.012) and longer eMUL (p = 0.049) had better UC recovery one month after RARP while eMUV (OR = 1.002, 95% CI = 1.000-1.003, p = 0.008) and VPSS score (OR = 0.886, 95% CI = 0.806-0.973, p = 0.011) were independent risk factors; The patients with younger age (p = 0.018), larger tMUV (p = 0.029), eMUV (p = 0.016) had better UC recovery three months after RARP. eMUV (OR = 1.002, 95% CI = 1.000-1.004, p = 0.042) and age (OR = 0.904, 95% CI = 0.818-0.998, p = 0.046) were independent risk factors. CONCLUSION: This clinical study shows that patients with larger MUV and longer MUL can return to UC earlier after surgery. Among that, eMUV is a better predictor.

Unveiling the structure and interactions of SOG1, a NAC domain transcription factor: An in-silico perspective.

SOG1 is a crucial plant-specific NAC domain family transcription factor and functions as the central regulator of DNA damage response, acting downstream of ATM and ATR kinases. In this study, various in-silico approaches have been employed for the characterization of SOG1 transcription factor in a comparative manner with its orthologues from various plant species. Amino acid sequences of more than a hundred SOG1 or SOG1-like proteins were retrieved and their relationship was determined through phylogenetic and motif analyses. Various physiochemical properties and secondary structural components of SOG1 orthologues were determined in selective plant species including Arabidopsis thaliana, Oryza sativa, Amborella trichopoda, and Physcomitrella patens. Furthermore, fold recognition or threading and homology-based three-dimensional models of SOG1 were constructed followed by subsequent evaluation of quality and accuracy of the generated protein models. Finally, extensive DNA-Protein and Protein-Protein interaction studies were performed using the HADDOCK server to give an insight into the mechanism of how SOG1 binds with the promoter region of its target genes or interacts with other proteins to regulate the DNA damage responses in plants. Our docking analysis data have shown the molecular mechanism of SOG1's binding with 5'-CTT(N)7AAG-3' and 5'-(N)4GTCAA(N)4-3' consensus sequences present in the promoter region of its target genes. Moreover, SOG1 physically interacts and forms a thermodynamically stable complex with NAC103 and BRCA1 proteins, which possibly serve as coactivators or mediators in the transcription regulatory network of SOG1. Overall, our in-silico study will provide meaningful information regarding the structural and functional characterization of the SOG1 transcription factor.

Quantifying water-use efficiency in plant canopies with varying leaf angle and density distribution.

BACKGROUND AND AIMS: Variation in architectural traits related to the spatial and angular distribution of leaf area can have considerable impacts on canopy-scale fluxes contributing to water-use efficiency (WUE). These architectural traits are frequent targets for crop improvement and for improving the understanding and predictions of net ecosystem carbon and water fluxes. METHODS: A three-dimensional, leaf-resolving model along with a range of virtually generated hypothetical canopies were used to quantify interactions between canopy structure and WUE by examining its response to variation of leaf inclination independent of leaf azimuth, canopy heterogeneity, vegetation density and physiological parameters. KEY RESULTS: Overall, increasing leaf area index (LAI), increasing the daily-averaged fraction of leaf area projected in the sun direction (Gavg) via the leaf inclination or azimuth distribution and increasing homogeneity had a similar effect on canopy-scale daily fluxes contributing to WUE. Increasing any of these parameters tended to increase daily light interception, increase daily net photosynthesis at low LAI and decrease it at high LAI, increase daily transpiration and decrease WUE. Isolated spherical crowns could decrease photosynthesis by ~60 % but increase daily WUE ≤130 % relative to a homogeneous canopy with equivalent leaf area density. There was no observed optimum in daily canopy WUE as LAI, leaf angle distribution or heterogeneity was varied. However, when the canopy was dense, a more vertical leaf angle distribution could increase both photosynthesis and WUE simultaneously. CONCLUSIONS: Variation in leaf angle and density distributions can have a substantial impact on canopy-level carbon and water fluxes, with potential trade-offs between the two. These traits might therefore be viable target traits for increasing or maintaining crop productivity while using less water, and for improvement of simplified models. Increasing canopy density or decreasing canopy heterogeneity increases the impact of leaf angle on WUE and its dependent processes.

Unsuspected Limitations of 3D Printed Model in Planning of Complex Aortic Aneurysm Endovascular Treatment.

OBJECTIVE: Static 3-dimensional (3D) printing became attractive for operative planning in cases that involve difficult anatomy. An interactive (low cost, fast) 3D print allowing deliberate surgical practice can be used to improve interventional simulation and planning. BACKGROUND: Endovascular treatment of complex aortic aneurysms is technically challenging, especially in case of narrow aortic lumen or significant aortic angulation (hostile anatomy). The risk of complications such as graft kinking and target vessel occlusion is difficult to assess based solely on traditional software measuring methods and remain highly dependent on surgeon skills and expertise. METHODS: A patient with juxtarenal AAA with hostile anatomy had a 3-dimensional printed model constructed preoperatively according to computed tomography images. Endovascular graft implantation in the 3D printed aorta with a standard T-Branch Cook (Cook® Medical, Bloomington, IN, USA) was performed preoperatively in the simulation laboratory enabling optimized feasibility, surgical planning and intraoperative decision making. RESULTS: The 3D printed aortic model proved to be radio-opaque and allowed simulation of branched endovascular aortic repair (BREVAR). The assessment of intervention feasibility, as well as optimal branch position and orientation was found to be useful for surgeon confidence and the actual intervention in the patient. There was a remarkable agreement between the 3D printed model and both CT and X-ray angiographic images. Although the technical success was achieved as planned, a previously deployed renal stent caused unexpected difficulty in advancing the renal stent, which was not observed in the 3D model simulation. CONCLUSION: The 3D printed aortic models can be useful for determining feasibility, optimizing planning and intraoperative decision making in hostile anatomy improving the outcome. Despite already offering satisfying accuracy at present, further advancements could enhance the 3D model capability to replicate minor anatomical deformities and variations in tissue density.

Musculoskeletal morphogenesis supports the convergent evolution of bat laryngeal echolocation.

The order Chiroptera (bats) is the second largest group of mammals. One of the essential adaptations that have allowed bats to dominate the night skies is laryngeal echolocation, where bats emit ultrasonic pulses and listen to the returned echo to produce high-resolution 'images' of their surroundings. There are two possible scenarios for the evolutionary origin of laryngeal echolocation in bats: (1) a single origin in a common ancestor followed by the secondary loss in Pteropodidae, or (2) two convergent origins in Rhinolophoidea and Yangochiroptera. Although data from palaeontological, anatomical, developmental and genomic studies of auditory apparatuses exist, they remain inconclusive concerning the evolutionary origin of bat laryngeal echolocation. Here we compared musculoskeletal morphogenesis of the larynx in several chiropteran lineages and found distinct laryngeal modifications in two echolocating lineages, rhinolophoids and yangochiropterans. Our findings support the second scenario that rhinolophoids and yangochiropterans convergently evolved advanced laryngeal echolocation through anatomical modifications of the larynx for ultrasonic sound generation and refinement of the auditory apparatuses for more detailed sound perception.

[Mental health, an ecosystem issue]. / La santé mentale, une question écosystémique.

The question of mental health can be approached using the three-dimensional model. In the light of the biological, environmental and circumstantial ingredients characterizing it, a critical analysis of both diagnosis and treatment can be proposed. The environment, like the individual, is both a factor and a player in psychological suffering. Treating one as well as the other is therefore the challenge of an ecosystemic approach.

Creation of a microsurgical neuroanatomy laboratory and virtual operating room: a preliminary study.

OBJECTIVE: A comprehensive understanding of microsurgical neuroanatomy, familiarity with the operating room environment, patient positioning in relation to the surgery, and knowledge of surgical approaches is crucial in neurosurgical education. However, challenges such as limited patient exposure, heightened patient safety concerns, a decreased availability of surgical cases during training, and difficulties in accessing cadavers and laboratories have adversely impacted this education. Three-dimensional (3D) models and augmented reality (AR) applications can be utilized to depict the cortical and white matter anatomy of the brain, create virtual models of patient surgical positions, and simulate the operating room and neuroanatomy laboratory environment. Herein, the authors, who used a single application, aimed to demonstrate the creation of 3D models of anatomical cadaver dissections, surgical approaches, patient surgical positions, and operating room and laboratory designs as alternative educational materials for neurosurgical training. METHODS: A 3D modeling application (Scaniverse) was employed to generate 3D models of cadaveric brain specimens and surgical approaches using photogrammetry. It was also used to create virtual representations of the operating room and laboratory environment, as well as the surgical positions of patients, by utilizing light detection and ranging (LiDAR) sensor technology for accurate spatial mapping. These virtual models were then presented in AR for educational purposes. RESULTS: Virtual representations in three dimensions were created to depict cadaver specimens, surgical approaches, patient surgical positions, and the operating room and laboratory environment. These models offer the flexibility of rotation and movement in various planes for improved visualization and understanding. The operating room and laboratory environment were rendered in three dimensions to create a simulation that could be navigated using AR and mixed reality technology. Realistic cadaveric models with intricate details were showcased on internet-based platforms and AR platforms for enhanced visualization and learning. CONCLUSIONS: The utilization of this cost-effective, straightforward, and readily available approach to generate 3D models has the potential to enhance neuroanatomical and neurosurgical education. These digital models can be easily stored and shared via the internet, making them accessible to neurosurgeons worldwide for educational purposes.

Metaverse Surgical Planning with Three-dimensional Virtual Models for Minimally Invasive Partial Nephrectomy.

The recent integration of new virtual visualization modalities with artificial intelligence and high-speed internet connection has opened the door to the advent of the metaverse in medicine. In this totally virtual environment, three-dimensional virtual models (3DVMs) of the patient's anatomy can be visualized and discussed via digital avatars. Here we present for the first time a metaverse preoperative clinical case discussion before minimally invasive partial nephrectomy. The surgeons' digital avatars met in a virtual room and participated in a virtual consultation on the surgical strategy and clamping approach before the procedure. Robotic or laparoscopic procedures are then carried out according to the simulated surgical strategy. We demonstrate how this immersive virtual reality experience overcomes the barriers of distance and how the quality of surgical planning is enriched by a great sense of "being there", even if virtually. Further investigation will improve the quality of interaction with the models and among the avatars.

Accuracy of non-medical and medical individuals in identifying cerebral cortical abnormality from three-dimensional printed models of magnetic resonance images in children with hypoxic ischemic injury.

Effective communication of imaging findings in term hypoxic ischemic injury to family members, non-radiologist colleagues and members of the legal profession can be extremely challenging through text-based radiology reports. Utilization of three-dimensional (D) printed models, where the actual findings of the brain can be communicated via tactile perception, is a potential solution which has not yet been tested in practice. We aimed to determine the sensitivity and specificity of different groups, comprising trained radiologists, non-radiologist physicians and non-physicians, in the detection of gross disease of the cerebral cortex from 3-D printed brain models derived from magnetic resonance imaging (MRI) scans of children. Ten MRI scans in children of varying ages with either watershed pattern hypoxic ischemic injury (cortical injury) or basal-ganglia-thalamus hypoxic ischemic injury pattern with limited perirolandic cortical abnormalities and 2 normal MRI scans were post processed and 3-D printed. In total, 71 participants reviewed the 12 models and were required to indicate only the brain models that they felt were abnormal (with a moderate to high degree of degree of confidence). The 71 participants included in the study were 38 laypeople (54%), 17 radiographic technologists (24%), 6 nurses (8%), 5 general radiologists (7%), 4 non-radiologist physicians- 3 pediatricians and 1 neurologist (6%) and 1 emergency medical services staff (1%). The sensitivity and specificity for detecting the abnormal brains of the 71 participants were calculated. Radiologists showed the highest sensitivity (72%) and specificity (70%). Non-radiologist physicians had a sensitivity of 67.5% and a specificity of 75%. Nurses had a sensitivity of 70% and a specificity of 41.7%. Laypeople (non-medical trained) had a sensitivity of 56.1% and a specificity of 55.3%. Radiologists' high sensitivity and specificity of 72% and 70%, respectively, validates the accuracy of the 3-D-printed models in reproducing abnormalities from MRI scans. The non-radiologist physicians also had a high sensitivity and specificity. Laypeople, without any prior training or guidance in looking at the models, had a sensitivity of 56.1% and a specificity of 55.3%. These results show the potential for use of the 3-D printed brains as an alternate form of communication for conveying the pathological findings of hypoxic ischemic injury of the brain to laypeople.

Biomarkers and experimental models for cancer immunology investigation.

The rapid advancement of tumor immunotherapies poses challenges for the tools used in cancer immunology research, highlighting the need for highly effective biomarkers and reproducible experimental models. Current immunotherapy biomarkers encompass surface protein markers such as PD-L1, genetic features such as microsatellite instability, tumor-infiltrating lymphocytes, and biomarkers in liquid biopsy such as circulating tumor DNAs. Experimental models, ranging from 3D in vitro cultures (spheroids, submerged models, air-liquid interface models, organ-on-a-chips) to advanced 3D bioprinting techniques, have emerged as valuable platforms for cancer immunology investigations and immunotherapy biomarker research. By preserving native immune components or coculturing with exogenous immune cells, these models replicate the tumor microenvironment in vitro. Animal models like syngeneic models, genetically engineered models, and patient-derived xenografts provide opportunities to study in vivo tumor-immune interactions. Humanized animal models further enable the simulation of the human-specific tumor microenvironment. Here, we provide a comprehensive overview of the advantages, limitations, and prospects of different biomarkers and experimental models, specifically focusing on the role of biomarkers in predicting immunotherapy outcomes and the ability of experimental models to replicate the tumor microenvironment. By integrating cutting-edge biomarkers and experimental models, this review serves as a valuable resource for accessing the forefront of cancer immunology investigation.

A Novel Prediction Method of Transfer-Assisted Action Oriented to Individual Differences for the Excretion Care Robot.

The excretion care robot's (ECR) accurate recognition of transfer-assisted actions is crucial during its usage. However, transfer action recognition is a challenging task, especially since the differentiation of actions seriously affects its recognition speed, robustness, and generalization ability. We propose a novel approach for transfer action recognition assisted by a bidirectional long- and short-term memory (Bi-LSTM) network combined with a multi-head attention mechanism. Firstly, we utilize posture sensors to detect human movements and establish a lightweight three-dimensional (3D) model of the lower limbs. In particular, we adopt a discrete extended Kalman filter (DEKF) to improve the accuracy and foresight of pose solving. Then, we construct an action prediction model that incorporates a fused Bi-LSTM with Multi-head attention (MHA Bi-LSTM). The MHA extracts key information related to differentiated movements from different dimensions and assigns varying weights. Utilizing the Bi-LSTM network effectively combines past and future information to enhance the prediction results of differentiated actions. Finally, comparisons were made by three subjects in the proposed method and with two other time series based neural network models. The reliability of the MHA Bi-LSTM method was verified. These experimental results show that the introduced MHA Bi-LSTM model has a higher accuracy in predicting posture sensor-based excretory care actions. Our method provides a promising approach for handling transfer-assisted action individual differentiation in excretion care tasks.

The Impact of Romantic Attachment Styles on Jealousy in Young Adults.

Background: Romantic attachment is reflected in various aspects of dyadic interaction in a couple, since it is a self-reinforcing system of cognitive, emotional and behavioral patterns. Romantic jealousy was shown to be associated with dimensions of attachment insecurity in various studies worldwide. Objectives: To identify differences in expressions of romantic jealousy based on romantic attachment style. To determine the influence of attachment-related anxiety and attachment-related avoidance on cognitive, emotional, and behavioral jealousy. Design: The sample comprised 171 heterosexual individuals. The "Experiences in Close Relationships - Revised" questionnaire (ECR-R; Fraley, Waller, & Brennan, 2000; adapted for Russian by Chursina, 2022) and "Multidimensional Jealousy Scale" (MJS; Pfeiffer, & Wong, 1989) were used. Results: A number of significant differences were identified between insecure and secure attachment styles. Avoidant attachment is characterized by cognitive jealousy, ambivalent attachment is characterized by cognitive and behavioral jealousy, while dismissing attachment showed no significant differences in the manifestations of jealousy in comparison with secure attachment style. Emotional jealousy is equally characteristic of all types. The primacy of romantic attachment in relation to cognitive and behavioral jealousy was also proved. Conclusion: The experience of jealousy differs among romantic attachment styles. Attachment-related anxiety is a predictor of intrusive thoughts and behavioral manifestations of jealousy, while attachment-related avoidance is less, the greater the manifestation of jealousy behaviors.

A simplified coronary model for diagnosis of ischemia-causing coronary stenosis.

BACKGROUND AND OBJECTIVE: The functional assessment of the severity of coronary stenosis from coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFR) has recently attracted interest. However, existing algorithms run at high computational cost. Therefore, this study proposes a fast calculation method of FFR for the diagnosis of ischemia-causing coronary stenosis. METHODS: We combined CCTA and machine learning to develop a simplified single-vessel coronary model for rapid calculation of FFR. First, a zero-dimensional model of single-vessel coronary was established based on CCTA, and microcirculation resistance was determined through the relationship between coronary pressure and flow. In addition, a coronary stenosis model based on machine learning was introduced to determine stenosis resistance. Computational FFR (cFFR) was then obtained by combining the zero-dimensional model and the stenosis model with inlet boundary conditions for resting (cFFRr) and hyperemic (cFFRh) aortic pressure, respectively. We retrospectively analyzed 75 patients who underwent clinically invasive FFR (iFFR), and verified the model accuracy by comparison of cFFR with iFFR. RESULTS: The average computing time of cFFR was less than 2 s. The correlations between cFFRr and cFFRh with iFFR were r = 0.89 (p < 0.001) and r = 0.90 (p < 0.001), respectively. Diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio for cFFRr and cFFRh were 90.7%, 95.0%, 89.1%, 76.0%, 98.0%, 8.7, 0.1 and 92.0%, 95.0%, 90.9%, 79.2%, 98.0%, 10.5, 0.1, respectively. CONCLUSIONS: The proposed model enables rapid prediction of cFFR and exhibits high diagnostic performance in selected patient cohorts. The model thus provides an accurate and time-efficient computational tool to detect ischemia-causing stenosis and assist with clinical decision-making.