Computed Tomography Data Research Articles

Using CT images to assist the segmentation of MR images via generalization: Segmentation of the renal parenchyma of renal carcinoma patients.

Developing deep learning models for segmenting medical images in multiple modalities with less data and annotation is an attractive and challenging task, which was previously discussed as being accomplished by complex external frameworks for bridging the gap between different modalities. Exploring the generalization ability of networks in medical images in different modalities could provide more simple and accessible methods, yet comprehensive testing could still be needed. To explore the feasibility and robustness of using computed tomography (CT) images to assist the segmentation of magnetic resonance (MR) images via the generalization, in the segmentation of renal parenchyma of renal cell carcinoma (RCC) patients. Nephrographic CT images and fat-suppressed T2-weighted (fs-T2W) images were retrospectively collected. The pure CT dataset included 116 CT images. Additionally, 240 MR images were randomly divided into subsets A and B. From subset A, three training datasets were constructed, each containing 40, 80, and 120 images, respectively. Similarly, three datasets were constructed from subset B. Subsequently, datasets with mixed modality were created by combining these pure MR datasets with the 116 CT images. The 3D-UNET models for segmenting the renal parenchyma in two steps were trained using these 13 datasets: segmenting kidneys and then the renal parenchyma. These models were evaluated in internal MR (n=120), CT (n=65) validation datasets, and an external validation dataset of CT (n=79), using the mean of the dice similarity coefficient (DSC). To demonstrate the robustness of generalization ability over different proportions of modalities, we compared the models trained with mixed modality in three different proportions and pure MR, using repeated measures analysis of variance (RM-ANOVA). We developed a renal parenchyma volume quantification tool by the trained models. The mean differences and Pearson correlation coefficients between the model segmentation volume and the ground truth segmentation volume were calculated for its evaluation. The mean DSCs of models trained with 116 data in CT in the validation of MR were 0.826, 0.842, and 0.953, respectively, for the predictions of kidney segmentation model on whole image, renal parenchymal segmentation model on kidneys with RCC and without RCC. For all models trained with mixed modality, the means of DSC were above 0.9, in all validations of CT and MR. According to the results of the comparison between models trained with mixed modality and pure MR, the means of DSC of the former were significantly greater or equal to the latter, at all three different proportions of modalities. The differences of volumes were all significantly lower than one-third of the volumetric quantification error of a previous method, and the Pearson correlation coefficients of volumes were all above 0.96 on kidneys with and without RCC of three validations. CT images could be used to assist the segmentation of MR images via the generalization, with or without the supervision of MR data. This ability showed acceptable robustness. A tool for accurately measuring renal parenchymal volume on CT and MR images was established.

Brief Report: Alternative Pulmonary Function Measures of Emphysema in People With HIV.

People with HIV (PWH) have nearly twice the risk of emphysema than people without HIV. This risk, which has been associated with HIV-mediated changes in the lung immune environment and more extensive radiographic emphysema, may result in different patterns of airflow limitation on pulmonary function testing (PFT) than those traditionally used in people without HIV. In this prospective cohort of PWH in Atlanta, Georgia, we analyzed PFT and chest computed tomography data from July 2013 through June 2018. After comparing the prevalence of PFT measures of airflow limitation for those with and without radiographic emphysema, we used binary recursive partitioning to identify PFT measures that differentiated between PWH with and without radiographic emphysema. Among 167 PWH who had both PFT and computed tomography data during the study period, 89 (53%) had radiographic emphysema. Those with radiographic emphysema were more likely to have airflow limitations on PFTs. Recursive partitioning identified partitions at a forced expiratory volume in 1 second to forced vital capacity ratio (FEV1/FVC) of 0.78 and a residual volume of 116% predicted. These partitions enabled the identification of 84 (94%) PWH with radiographic emphysema, in contrast to the traditional diagnostic criteria of an FEV1/FVC ratio of 0.7, which only identified 49 (55%) of those with radiographic emphysema. Emphysema in PWH may have different patterns of airflow limitation on PFTs that are not adequately captured by traditional diagnostic criteria. Future studies can seek to validate these findings and determine optimal thresholds for diagnosing HIV-associated emphysema.

Initial sarcopenia and body composition changes as prognostic factors in cervical cancer patients treated with concurrent chemoradiation: An artificial intelligence-based volumetric study

ObjectivesThis study aimed to investigate the influence of baseline sarcopenia and changes in body composition on survival during cervical cancer treatment. MethodsPatients diagnosed with stage IB1-IVB cervical cancer who underwent primary concurrent chemoradiation therapy (CCRT) between 2002 and 2022 were included. The exclusion criteria were prior radical hysterectomy, lack of pretreatment computed tomography (CT) imaging, or significant comorbidities. An artificial intelligence-based automatic segmentation program assessed body composition by analyzing CT images, defining L3 sarcopenia (L3 skeletal muscle index [SMI] <39cm2/m2) and volumetric sarcopenia (volumetric SMI <180.4 cm3/m3). Comparative and multivariate analyses identified the prognostic factors. The impact of body component changes during CCRT was explored. ResultsAmong 347 patients, there were 125 recurrences and 59 deaths (median follow-up, 50.5 months). Seven patients were excluded from the volumetric sarcopenia analysis because of incomplete baseline CT data, and 175 patients were included in the analysis of body composition changes. Patients with L3 sarcopenia had a lower 5-year progression-free survival (PFS) rate (55.6% vs. 66.2%, p = 0.027), while those with volumetric sarcopenia showed a poorer 5-year overall survival rate (76.5% vs. 85.1%, p = 0.036). Patients with total fat loss during CCRT had a worse 5-year PFS rate than those with total fat gain (61.9% vs. 73.8%, p = 0.029). Multivariate analyses revealed that total fat loss (adjusted hazard ratio [aHR], 2.172; 95% confidence interval [CI], 1.066–4.424; p = 0.033) was a significant factor for recurrence, whereas L3 sarcopenia was not. Volumetric sarcopenia increased the risk of death by 1.75-fold (aHR, 1.750; 95% CI, 1.012–3.025; p = 0.045). ConclusionsAmong patients with cervical cancer undergoing CCRT, initial volumetric sarcopenia and fat loss during treatment are survival risk factors. These findings suggest the potential importance of personalized supportive care, including tailored nutrition and exercise interventions.

Analysis and Visualization of Inter-/Intra-surgeon Variability Using Surgical Simulation for Partial Anomalous Pulmonary Venous Connection Repair.

There may be inter-/intra-surgeon variability in the repair of congenital heart defects. The objective was to analyze and visualize inter-/intra-surgeon variability in the level of patch suture lines and in the shape and size of patches developed through surgical simulation for partial anomalous pulmonary venous connection (PAPVC) repair using a patient-specific 3D-printed heart model. A patient with PAPVC and preoperative computed tomography data were selected, and a patient-specific heart model was obtained. Two different exposures on the model were tested. Two surgeons were enrolled. Both surgeons performed a single-patch repair on four heart models with one exposure and four models with the other. On the potential suture line, 20 points common in each model were allocated. The level of patch suture lines was represented as a deviation from the 20 points. The shape and size of the patches were analyzed and visualized using geometric morphometrics approaches, using the 20 points as landmarks to represent the patches. There was inter-surgeon variability in the level of patch suture lines, and the variability was higher in particular locations. There was inter-surgeon variability in the shape and size of patches, which was not affected by the exposures. The inter-surgeon variability in the shape of patches was higher in particular locations. There was intra-surgeon variability in the shape of patches. Inter-/intra-surgeon variability was analyzed and visualized by the surgical simulation using geometric morphometrics approaches. Further studies are needed to scrutinize whether the variability affects postoperative hemodynamics in actual surgery.

Implementing verifiable oncological imaging by quality assurance and optimization (i‑Violin) : Protocol for aEuropean multicenter study.

Advanced imaging techniques play apivotal role in oncology. Alarge variety of computed tomography (CT) scanners, scan protocols, and acquisition techniques have led to awide range in image quality and radiation exposure. This study aims at implementing verifiable oncological imaging by quality assurance and optimization (i-Violin) through harmonizing image quality and radiation dose across Europe. The 2‑year multicenter implementation study outlined here will focus on CT imaging of lung, stomach, and colorectal cancer and include imaging for four radiological indications: diagnosis, radiation therapy planning, staging, and follow-up. Therefore, 480 anonymized CT data sets of patients will be collected by the associated university hospitals and uploaded to arepository. Radiologists will determine key abdominopelvic structures for image quality assessment by consensus and subsequently adapt apreviously developed lung CT tool for the objective evaluation of image quality. The quality metrics will be evaluated for their correlation with perceived image quality and the standardized optimization strategy will be disseminated across Europe. The results of the outlined study will be used to obtain European reference data, to build teaching programs for the developed tools, and to create aculture of optimization in oncological CT imaging. The study protocol and rationale for i‑Violin, aEuropean approach for standardization and harmonization of image quality and optimization of CT procedures in oncological imaging, is presented. Future results will be disseminated across all EU member states, and i‑Violin is thus expected to have asustained impact on CT imaging for cancer patients across Europe.

Prediction of Femoral Bone Strength in the Presence of Tumors and Tumor-like Lesions Using Finite Element Analysis.

Patients with bone tumors in their femurs are at risk of developing pathological fractures. Tumors with high fracture risk, especially fragile malignant lesions, are treated surgically. However, it is difficult to estimate bone strength based on clinical and radiographic findings. This study aimed to determine whether finite element analysis (FEA) provides useful information on the bone strength of femurs with tumors and tumor-like lesions. Total femoral computed tomography (CT) data (slice thickness, 0.5 mm) were retrospectively obtained from 18 patients with femoral bone tumors. Three-dimensional FEA of femurs were developed using CT data. The virtual femoral head compression test and direct three-point bending test were performed on the femurs using FEA to predict bone strength and fracture location. The compression direction was parallel to the mechanical axis, whereas that of the three-point bending test was applied to the tumor itself. In the femoral head compression test using FEA, 13 out of 18 femurs with bone tumors fractured at the femoral head, while 14 out of 18 femurs fractured at the tumor site during the virtual direct three-point bending test. The median loads predicted using the femoral head compression test were significantly higher than those predicted by the direct three-point bending test. The FEA results indicated that pathological fractures are unlikely to occur during normal walking. Direct external forces applied to the tumor body may lead to fractures.

Relationship between coronary atherosclerotic lesion and arterial stiffness in patients with coronary artery disease

Abstract Introduction Some of the previous studies demonstrated that arterial stiffness independently predicts mortality and morbidity associated with CAD. Purpose to evaluate the relationship between coronary atherosclerosis severity and arterial stiffness. Material and methods The study included 158 people aged 40 to 70 years: control group – 25 people (mean age 61,7±6,6 years; 21 men and 4 women) without cardiovascular diseases (CVD) and 133 patients (mean age 62,5±6,9 years; 80 men and 53 women) with CAD, confirmed by coronary angiography (CAG). Arterial stiffness was assessed using applanation tonometry (AT). Аssessment of the coronary calcium (CC) was performed with computer tomography (CT). Results In 133 patients with CAD, the results of AT were compared with the degree of atherosclerotic lesion according to CT and CAG data. All patients were divided into groups depending on the CC value. Group I included 19 people with a CC value of 0, group II - 55 people with a CC of up to 400, and group III - 59 patients with a CC of more than 400. With an increase in the degree of the atherosclerotic lesion, the values of peripheral and central pulse pressure (PP), augmentation index (AIx), additional augmentation index normalised for heart rate of 75 bpm (AIx@HR75) and pulse wave velocity (PWV) statistically significantly increased (Table 1). Indicators characterising augmentation of сentral PP and arterial stiffness also increased. Conclusion Increases in Pulse Pressure, Augmentation Index, and Pulse Wave Velocity reflect the worsening of atherosclerosis in coronary arteries, thereby indicating a higher risk of cardiovascular complications. Monitoring of these parameters can be crucial for early diagnosis and prevention of major adverse cardiovascular events.

Resolution of silent left atrial thrombi and clinical outcomes in patients with atrial fibrillation: insight from the LAT trial

Abstract Background Silent thrombi in the left atrium (LA), which are thrombi that have not yet caused thromboembolism, are occasionally observed in patients undergoing transesophageal echocardiography (TEE) for atrial fibrillation (AF). However, there is limited data regarding the impact of resolving these silent LA thrombi (LAT) on patient outcomes. Methods We conducted a retrospective review of clinical records from 2010 to 2018 at six hospitals, involving 17,436 TEE procedures for patients with AF. Among these, 297 patients (1.7%) were identified with silent LAT. Of these, 169 patients with follow-up TEE or cardiac computed tomography data for assessing the resolution of LAT were included in this study. The study population were categorized into two groups: the successful resolution group, defined as those with complete LAT resolution without any related events (N=130), and the failed resolution group (N=39). The latter included patients with residual LAT at the last follow-up (N=26), individuals with thromboembolic events (N=8), or those who required surgical intervention for LAT (N=5). Results During the median follow-up period of 394 days (interquartile range, 373-421 days) following thrombi detection, ischemic stroke and systemic thromboembolism (IS/SE) were observed in 10 cases, major bleeding in 23 cases, and all-cause death in 8 cases. In comparison to the successful resolution group, the failed resolution group not only exhibited a higher incidence of IS/SE (1.5% in the successful vs. 20.5% in the failed resolution group, Log-rank p &amp;lt; 0.001) but also showed trends toward increased major bleeding (10% vs. 23.1%, p = 0.033) and higher total mortality rates (3.1% vs. 10.3%, p = 0.05). These differences in composite endpoints were also statistically significant (13.9% vs. 35.9%, p = 0.001). Conclusion In patients with silent LATs were identified, non-resolution of these LATs was associated with not only a higher incidence of IS/SE but also increased rates of major bleeding and all-cause mortality. Conversely, patients who experienced LAT resolution exhibited more preferable prognoses. The status of LAT resolution is closely associated with patient outcomes, underscoring the importance of monitoring LAT resolution in stratifying patient prognoses.

Inter-ethnic heterogeneity in valvular morphology and aortopathy of a worldwide bicuspid aortic valve cohort referred for TAVR

Abstract Background Bicuspid aortic valve (BAV) represents one of the most common congenital heart disease. BAV stenosis tipycally occurs in younger, low-surgical risk patients compared to tricuspid aortic valves (TAV). With the predicted expansion of trans-catheter aortic valve replacement (TAVR) into lower-risk patients, the proportion of BAV is expected to rise. Although some observational studies have investigated the characteristics of Asian versus European patients with BAV undergoing TAVR, little is known about the inter-ethnic differences within the large and diverse Asian, African, Russian, and Caucasian population. Purpose To evaluate the inter-ethnic differences of aortic valve morphology, annular size and associated aortopathy, in a worldwide population of patients with severe aortic stenosis referred for TAVR. Methods Cardiovascular multislice computed tomography data of patients with severe aortic valve stenosis referred for TAVR worldwide were obtained from the database of the Meril Life Core Lab. Inter-ethnic and epidemiological differences in terms of valvular phenotype, annular size and aortic morphology were evaluated with particular focus on patients with BAV. Results Among 12,712 patients (59% male), n=3,203 subjects (25%) exhibited a BAV morphology. According to the Siever’s BAV classification, type 1 (71%, n=2,284) was the most prevalent BAV morphology and particularly Type 1a was the most common in almost all population, with 26% exhibiting a type 0 BAV, while only 3% of the patients (n= 92) had a type 2 (Table 1). A significantly higher prevalence of severe calcium score (&amp;gt;1000 mm3) was found in patients with BAV compared with patients exhibiting a TAV morphology (51% vs. 32, p&amp;lt;0.01). Additionally, larger ascending aorta (AA) diameter (AA &amp;gt;40 mm) (BAV: 31% vs TAV 7%, p = 0.04), along with a higher prevalence of horizontal aorta (HA) (BAV: 20% vs TAV: 9%, p&amp;lt;0.01) was found in patients with BAV compared with TAV. As for inter-ethnic characteristics, there was a higher prevalence of BAV in Indian and Asian Pacific populations (respectively 43% and 28%), with the African population exhibiting the lowest prevalence (7%, n= 28, p=0.02) (Table 2). In Indian patients a higher prevalence of BAV was found in an earlier age (61-70 years old) compared to Western countries (p=0.05). Finally, smaller annular size (456±98 mm2 vs 584±99 mm2, p&amp;lt;0.01) and lower coronary ostia height (Asia and India: RCA 14.5±3 mm, LCA 14±2.9mm vs Caucasian and Russian: RCA 16±3.2 mm, LCA 16.9±3.3mm; p&amp;lt;0.01) were found in the Asian and Indian population when compared with Russian, African and Caucasian subjects. Conclusions BAV morphology, aortopathy and annular size resulted widely heterogenous according to the ethnicity and geographical origin of patients referred for TAVR worldwide. These features may lead different therapeutical decision making and outcomes following TAVR in patients with BAV.Table 1Table 2

Developing endoscopic cell sheet delivery device using a beating human heart simulator and a pig model for minimally invasive cardiac regenerative therapy

Abstract Introduction Recently, clinical trials have commenced for cardiac regenerative therapy utilizing stem cells in patients with heart failure. Among the various transplantation approaches, there is a growing demand for less invasive methods to transplant sheet/patch-shaped cell products onto the heart surface, rather than resorting to conventional open surgery. This is particularly important considering the need for immunosuppressants due to allogeneic cell transplantation. Objective This study aims to develop a device for endoscopic transplantation of cell sheets onto the beating heart surface. Methods Prototype devices, initially developed in our prior study using a static heart model (Regenerative Therapy, 2020), were refined to better suit the cell sheet transplantation procedure onto a beating heart. We constructed a three-dimensional (3D) model of a beating heart located inside a thoracic cavity model, based on human computed tomography data and a 3D printer dedicated to simulating endoscopic surgical procedures. Human mesenchymal stromal cell (MSC)-derived cell sheets were prepared using temperature-responsive culture dishes and transferred onto a beating heart model pulsating at 80 beats per minute. We assessed the technical feasibility (N=8). Furthermore, skeletal muscle tissue was harvested from the thigh of the Clawn miniature pigs, and skeletal myoblasts were cultured from enzymatically digested tissue to create a cell sheet for autologous transplantation (8.0×10⁶ cells/sheet). Subsequently, the cell sheets labeled with Hoechst 33342 were endoscopically transplanted onto the pig heart surface (N=2). The pigs were sacrificed one week later, and the engraftment of the cell sheet was histologically evaluated. Results Successful deployment of MSC sheets onto the beating heart model was achieved in all procedures with one trial (100% success rate). The procedure duration from device insertion to the completion of cell sheet transplantation averaged 142±19 seconds. In experiments on autologous transplantation of myoblast cell sheets, two cases were successfully accomplished, with the transplanted cell sheet positive for Hoechst 33342 observed on the heart surface. Conclusion We have developed an endoscopic cell sheet delivery device using a pulsating heart model and a pig model, which holds promise for minimally invasive cardiac regenerative therapy in the future. Further investigations into the safety of the procedure are warranted for the clinical application of this system.

Native Sinus Hemodynamics and Thrombosis in Transcatheter Heart Valve: Effect of Implant Depth and Coronary Flow.

This study aimed to investigate the hemodynamic and anatomic factors associated with sinus thrombosis following transcatheter aortic valve replacement (TAVR), integrating invivo patient data analysis and invitro experiments. Postprocedural, 4-dimensional, multiphase computed tomography data from 211 patients enrolled in the ADAPT-TAVR (Anticoagulation Versus Dual Antiplatelet Therapy for Prevention of Leaflet Thrombosis and Cerebral Embolization After Transcatheter Aortic Valve Replacement) study were analyzed. The prevalence of native sinus thrombosis was examined in relation to valve type, implant depth, and anatomic features. Invitro experiments used particle image velocimetry to observe changes in sinus flow based on the transcatheter heart valves (23-mm SAPIEN3, Edwards Lifesciences; and 29-mm CoreValve, Medtronic) height and coronary artery flow. Native sinus thrombosis was more common in self-expanding valves (39.1% versus 14.9%, P=0.004). In per-cusp analysis of invivo patient data, adjusted transcatheter heart valve implant depth (odds ratio, 1.2 [95% CI, 1.1-1.3]; P<0.001), noncoronary sinus of Valsalva (odds ratio, 4.0 [95% CI, 2.0-7.8]; P<0.001), sinus inflow diameter (odds ratio, 0.8 [95% CI, 0.6-0.9]; P=0.008), and implanted valve size (odds ratio, 0.8 [95% CI, 0.7-1.0]; P=0.025) were significant factors associated with native sinus thrombosis. In the invitro experiments, CoreValve showed noticeable flow stasis compared with SAPIEN3. High-positioned SAPIEN3 was linked to reduced velocity within the native sinus of Valsalva. Coronary artery flow led to higher sinus velocity and improved particle washout, reducing sinus thrombosis risk. This study provides insights into the relationship between transcatheter heart valve deployment and native sinus thrombosis, emphasizing the role of anatomic factors in relation to the risk of sinus thrombosis.

Machine learning for pacemaker implantation prediction after TAVI using multimodal imaging data

Pacemaker implantation (PMI) after transcatheter aortic valve implantation (TAVI) is a common complication. While computed tomography (CT) scan data are known predictors of PMI, no machine learning (ML) model integrating CT with clinical, ECG, and transthoracic echocardiography (TTE) data has been proposed. This study investigates the contribution of ML methods to predict PMI after TAVI, with a focus on the role of CT imaging data. A retrospective analysis was conducted on a cohort of 520 patients who underwent TAVI. Recursive feature elimination with SHAP values was used to select key variables from clinical, ECG, TTE, and CT data. Six ML models, including Support Vector Machines (SVM), were trained using these selected variables. The model’s performance was evaluated using AUC-ROC, F1 score, and accuracy metrics. The PMI rate was 18.8%. The best-performing model achieved an AUC-ROC of 92.1% ± 4.7, an F1 score of 71.8% ± 9.9, and an accuracy of 87.9% ± 4.7 using 22 variables, 9 of which were CT-based. Membranous septum measurements and their dynamic variations were critical predictors. Our ML model provides robust PMI predictions, enabling personalized risk assessments. The model is implemented online for broad clinical use.

Application of Mirror Image 3D-Printing Technology Bone Cement in Treatment of Stage IIIb Necrosis of the Lunate Bone.

At present, conventional operations are weak for pain relief and restoring the carpal joint function in the treatment of avascular necrosis of the lunate bone. Mirror image 3-dimensional (3D)-printing technology has rarely been reported for the treatment of lunate bone necrosis, The use of mirror 3D-printed lunar bone replacement and bone cement technology in the treatment of stage IIIb lunar bone necrosis has been rarely reported in previous literature. Personalized customized 3D-printed prostheses have become an effective solution for solving many complex cases, and the flexible application of bone cement technology can also achieve satisfactory clinical results. The authors report 3 patients who underwent mirror printing of lunar bone prostheses based on healthy side lunar bone computed tomography data, 3D printing of lunar bone prostheses replacement through small incisions, and intraoperative selection of alternative bone cement technology based on actual conditions. Mirror image 3D printing relieved the pain and resulted in satisfactory functional recovery for stage IIIb lunate bone necrosis.

Motion and anatomy dual aware lung ventilation imaging by integrating Jacobian map and average CT image using dual path fusion network.

Deep learning-based computed tomography (CT) ventilation imaging (CTVI) is a promising technique for guiding functional lung avoidance radiotherapy (FLART). However, conventional approaches, which rely on anatomical CT data, may overlook important ventilation features due to the lack of motion data integration. This study aims to develop a novel dual-aware CTVI method that integrates both anatomical information from CT images and motional information from Jacobian maps to generate more accurate ventilation images for FLART. A dataset of 66 patients with four-dimensional CT (4DCT) images and reference ventilation images (RefVI) was utilized to develop the dual-path fusion network (DPFN) for synthesizing ventilation images (CTVIDual). The DPFN model was specifically designed to integrate motion data from 4DCT-generated Jacobian maps with anatomical data from average 4DCT images. The DPFN utilized two specialized feature extraction pathways, along with encoders and decoders, designed to handle both 3D average CT images and Jacobian map data. This dual-processing approach enabled the comprehensive extraction of lung ventilation-related features. The performance of DPFN was assessed by comparing CTVIDual to RefVI using various metrics, including Spearman's correlation coefficients (R), Dice similarity coefficients of high-functional region (DSCh), and low-functional region (DSCl). Additionally, CTVIDual was benchmarked against other CTVI methods, including a dual-phase CT-based deep learning method (CTVIDLCT), a radiomics-based method (CTVIFM), a super voxel-based method (CTVISVD), a Unet-based method (CTVIUnet), and two deformable registration-based methods (CTVIJac and CTVIHU). In the test group, the mean R between CTVIDual and RefVI was 0.70, significantly outperforming CTVIDLCT (0.68), CTVIFM (0.58), CTVISVD (0.62), and CTVIUnet (0.66), with p<0.05. Furthermore, the DSCh and DSCl values of CTVIDual were 0.64 and 0.80, respectively, outperforming CTVISVD (0.63; 0.73) and CTVIUnet (0.62; 0.77). The performance of CTVIDual was also significantly better than that of CTVIJac and CTVIHU. A novel dual-aware CTVI model that integrates anatomical and motion information was developed to synthesize lung ventilation images. It was shown that the accuracy of lung ventilation estimation could be significantly enhanced by incorporating motional information, particularly in patients with tumor-induced blockages. This approach has the potential to improve the accuracy of CTVI, enabling more effective FLART.

Intraoperative navigation in craniofacial surgery.

Craniofacial surgery requires comprehensive anatomical knowledge of the head and neck to ensure patient safety and surgical precision. Over recent decades, there have been significant advancements in imaging techniques and the development of real-time surgical navigation systems. Intraoperative navigation technology aligns surgical instruments with imaging-derived information on patient anatomy, enabling surgeons to closely follow preoperative plans. This system functions as a radiologic map, improving the accuracy of instrument placement and minimizing surgical complications. The introduction of first-generation navigation systems in the early 1990s revolutionized surgical procedures by enabling real-time tracking of instruments using preoperative imaging. Initially utilized in neurosurgery, intraoperative navigation has since become standard practice in otolaryngology, cranio-maxillofacial surgery, and orthopedics. Since the 2000s, second-generation navigation systems have been developed to meet the growing demand for precision across various surgical specialties. The adoption of these systems in craniofacial surgery has been slower, but their use is increasing, particularly in procedures such as foreign body removal, facial bone fracture reconstruction, tumor resection, and craniofacial reconstruction and implantation. In Korea, insurance coverage for navigation in craniofacial surgery began in 2021, and new medical technologies for orbital wall fracture treatment were approved in August 2022. These technologies have only recently become clinically available, but are expected to play an increasingly important role in craniofacial surgery. Intraoperative navigation enhances operative insight, improves target localization, and increases surgical safety. Although these systems have a steep learning curve and initially prolong surgery, efficiency improves with experience. Calibration issues, registration errors, and soft tissue deformation can introduce inaccuracies. Nonetheless, navigation technology is evolving, and the integration of intraoperative computed tomography data holds promise for further enhancements of surgical accuracy. This paper discusses the various types and applications of navigation employed in craniofacial surgery, highlighting their benefits and limitations.

Exploring the density and morphology of coconut structures at two locations: a time-based analysis using computer tomography.

The study aimed to observe the internal structure of coconuts from two locations (coastal and non-coastal) using computed tomography (CT). Seventy-six mature coconuts were collected from Wenchang and Ding'an cities in Hainan Province. These coconuts were scanned four times using CT, with a two-week interval between each scan. CT data were post-processed to reconstruct two-dimensional slices and three-dimensional models. The density and morphological parameters of coconut structures were measured, and the differences in these characteristics between the two groups and the changes over time were analyzed. Time and location had interactive effects on CT values of embryos, solid endosperms and mesocarps, morphological information such as major axis of coconut, thickness of mesocarp, volume of coconut water and height of bud (p<0.05). Planting location and observation time can affect the density and morphology of some coconut structures.

Image-Based Peridynamic Modeling-Based Micro-CT for Failure Simulation of Composites

By utilizing computed tomography (CT) technology, we can gain a comprehensive understanding of the specific details within the material. When combined with computational mechanics, this approach allows us to predict the structural response through numerical simulation, thereby avoiding the high experimental costs. In this study, the tensile cracking behavior of carbon–silicon carbide (C/SiC) composites is numerically simulated using the bond-based peridynamics model (BB-PD), which is based on geometric models derived from segmented images of three-dimensional (3D) CT data. To obtain results efficiently and accurately, we adopted a deep learning-based image recognition model to identify the kinds of material and then the pixel type that corresponds to the material point, which can be modeled by BB-PD for failure simulation. The numerical simulations of the composites indicate that the proposed image-based peridynamics (IB-PD) model can accurately reconstruct the actual composite microstructure. It can effectively simulate various fracture phenomena such as interfacial debonding, crack propagation affected by defects, and damage to the matrix.

Validation of a multi-parameter algorithm for personalized contrast injection protocol in liver CT

BackgroundIn liver computed tomography (CT), tailoring the contrast injection to the patient’s specific characteristics is relevant for optimal imaging and patient safety. We evaluated a novel algorithm engineered for personalized contrast injection to achieve reproducible liver enhancement centered on 50 HU.MethodsFrom September 2020 to August 31, 2022, CT data from consecutive adult patients were prospectively collected at our multicenter premises. Inclusion criteria consisted of an abdominal CT referral for cancer staging or follow-up. For all examinations, a web interface incorporating data from the radiology information system (patient details and examination information) and radiographer-inputted data (patient fat-free mass, imaging center, kVp, contrast agent details, and imaging phase) were used. Calculated contrast volume and injection rate were manually entered into the CT console controlling the injector. Iopamidol 370 mgI/mL or Iohexol 350 mgI/mL were used, and kVp varied (80, 100, or 120) based on patient habitus.ResultsWe enrolled 384 patients (mean age 61.2 years, range 21.1–94.5). The amount of administered iodine dose (gI) was not significantly different across contrast agents (p = 0.700), while a significant increase in iodine dose was observed with increasing kVp (p < 0.001) and in males versus females (p < 0.001), as expected. Despite the differences in administered iodine load, image quality was reproducible across patients with 72.1% of the examinations falling within the desirable range of 40–60 HU.ConclusionThis study validated a novel algorithm for personalized contrast injection in adult abdominal CT, achieving consistent liver enhancement centered at 50 HU.Relevance statementIn healthcare’s ongoing shift towards personalized medicine, the algorithm offers excellent potential to improve diagnostic accuracy and patient management, particularly for the detection and follow-up of liver malignancies.Key PointsThe algorithm achieves reproducible liver enhancement, promising improved diagnostic accuracy and patient management in diverse clinical settings.The real-world study demonstrates this algorithm’s adaptability to different variables ensuring high-quality liver imaging.A personalized algorithm optimizes liver CT, improving the visibility, conspicuity, and follow-up of liver lesions.Graphical

Anatomical and Computed Tomography Study of the Mandible of the Patagonian Huemul (Hippocamelus bisulcus): Ecological and Clinical Insights.

Given the high prevalence of skeletal and mandibular diseases in the Patagonian Huemul, comprehensive anatomical studies are essential to understand the impact of nutritional deficiencies and support conservation efforts. The aim of this study is to provide a detailed anatomical characterisation of three exhumed mandibles of Patagonian huemul (Hippocamelus bisulcus) through three-dimensional reconstructions obtained from computed tomography data and semi-automatic segmentation, documenting their distinctive features. The findings revealed distinctive features in the mandible, consistent with the browsing habits of herbivores, such as a robust coronoid process, a wide and deep pterygoid fossa, a significantly lower mandibular condyle compared to other deer species and a unique configuration of the mandibular canal with a curved caudal portion and a straight rostral portion. These anatomical adaptations are likely related to the species' feeding habits and behaviour. The study also addressed the challenges of researching an endangered species, given that access to biological material is restricted by strict regulations in Chile and Argentina. These restrictions limited the available sample size and hindered the acquisition of additional specimens, which could affect the generalisation of the results. Despite these limitations, the research provides valuable anatomical insights that are fundamental for the biology, clinical practice and management of specimens. In conclusion, the mandibles of both juvenile and adult Patagonian huemul demonstrate distinctive features characteristic of browsing herbivores. The findings can serve as a basis for future comparative studies on mandibular anatomy and function in this endangered deer species as well as in other herbivorous deer.

Mechanical Performance of Cellulose Nanocrystal and Bioceramic-Based Composites for Surgical Training.

This study evaluated the mechanical performance of a cellulose nanocrystal (CNC)-based composite, consisting of hydroxyapatite and natural fibers, mimicking the mechanical properties of real bone. The effect of natural nanofibers on the cutting force of the composite was evaluated for suitability in surgical training. Although hydroxyapatite has been extensively studied in bone-related applications, the exploration of epoxy-based composites incorporating both hydroxyapatite and CNC represents a novel approach. The evaluation involved a load cell with an oscillating saw. The uniform distribution of CNCs within the composite was assessed using 3D X-ray imaging. The cutting force was found to be 4.005 ± 0.5469 N at a feed rate of 0.5 mm/s, comparable to that required when cutting real bone with the osteon at 90°. The 90-degree orientation of the osteon aligns with the cutting direction of the oscillating saw when performing knee replacements on the tibia and femur bones. The addition of CNCs resulted in changes in fracture toughness, leading to increased material fragmentation and surface irregularities. Furthermore, the change in the cutting force with depth was similar to that of real bone. The developed composite material enables bone-cutting surgeries using bioceramics and natural fibers without the risks associated with cadavers or synthetic fibers. Mold-based computed tomography data allows for the creation of various bone forms, enhancing skill development for surgeons.