Computed Tomography Angiography Data Research Articles

Projected augmented reality in DIEP flap breast reconstruction: Projecting perforators on the skin using dynamic infrared thermography

BackgroundDynamic infrared thermography (DIRT) is a quick and non-invasive technique for perforator mapping in free flaps that provides real-time information. After a cold challenge, areas best supplied with blood become visible hotspots on color-coded maps, indicating perforators. This study presents a proof of principle for a new and innovative feature of DIRT, where projected augmented reality is used to directly display thermal images on the patient’s abdomen prior to the deep inferior epigastric artery perforator (DIEP) flap breast reconstruction. MethodsA self-aligning projection device prototype (Anatomy Projector) equipped with an integrated thermal camera was used to obtain thermal information and project the color-coded map directly on the patient’s abdomen before DIEP flap breast reconstruction. Projected DIRT hotspots were verified using a hand-held Doppler, and compared to the vascularity on computed tomography angiography (CTA), and intraoperative perforator measurements following a Cartesian grid. ResultsA total of 514 DIRT hotspots were projected in 50 patients, among them 97.3% could be verified using Doppler. The positive predictive value for CTA was 74.5%. Intraoperative measurements yielded 132 perforators in 71 flaps, among them 75 perforators (56.8%) correlated with projected DIRT hotspots, and half of them (54.7%) appeared within the first 5 emerging hotspots. ConclusionThis study showed that real-time display of thermal data in DIEP flap breast reconstruction is feasible via projected augmented reality. Projection facilitates convenient marking of hotspots, and a high resemblance to Doppler and CTA data was observed. Further research should assess the added value of projecting thermal images intraoperatively and in other fields of plastic surgery.

Patient-Specific Haemodynamic Analysis of Virtual Grafting Strategies in Type-B Aortic Dissection: Impact of Compliance Mismatch.

Compliance mismatch between the aortic wall and Dacron Grafts is a clinical problem concerning aortic haemodynamics and morphological degeneration. The aortic stiffness introduced by grafts can lead to an increased left ventricular (LV) afterload. This study quantifies the impact of compliance mismatch by virtually testing different Type-B aortic dissection (TBAD) surgical grafting strategies in patient-specific, compliant computational fluid dynamics (CFD) simulations. A post-operative case of TBAD was segmented from computed tomography angiography data. Three virtual surgeries were generated using different grafts; two additional cases with compliant grafts were assessed. Compliant CFD simulations were performed using a patient-specific inlet flow rate and three-element Windkessel outlet boundary conditions informed by 2D-Flow MRI data. The wall compliance was calibrated using Cine-MRI images. Pressure, wall shear stress (WSS) indices and energy loss (EL) were computed. Increased aortic stiffness and longer grafts increased aortic pressure and EL. Implementing a compliant graft matching the aortic compliance of the patient reduced the pulse pressure by 11% and EL by 4%. The endothelial cell activation potential (ECAP) differed the most within the aneurysm, where the maximum percentage difference between the reference case and the mid (MDA) and complete (CDA) descending aorta replacements increased by 16% and 20%, respectively. This study suggests that by minimising graft length and matching its compliance to the native aorta whilst aligning with surgical requirements, the risk of LV hypertrophy may be reduced. This provides evidence that compliance-matching grafts may enhance patient outcomes.

Efficacy of Coronary Calcium Score in Predicting Coronary Artery Morphology in Patients With Obstructive Coronary Artery Disease

BackgroundCoronary artery calcium score (CACS) is an established marker of coronary artery disease (CAD) and has been extensively used to stratify risk in asymptomatic individuals. However, the value of CACS in predicting plaque morphology in patients with advanced CAD is less established. The present analysis aims to assess the association between CACS and plaque characteristics detected by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) imaging in patients with obstructive CAD. MethodsSeventy patients with obstructive CAD underwent coronary computed tomography angiography (CTA) and 3-vessel NIRS-IVUS imaging were included in the present analysis. The CTA data were used to measure the CACS in the entire coronary tree and the segments assessed by NIRS-IVUS, and these estimations were associated with the NIRS-IVUS measurements at a patient and segment level. ResultsIn total, 65 patients (188 segments) completed the study protocol and were included in the analysis. A weak correlation was noted between the CACS, percent atheroma volume (r = 0.271, P = .002), and the calcific burden measured by NIRS-IVUS (r = 0.648, P < .001) at patient-level analysis. Conversely, there was no association between the CACS and the lipid content, or the incidence of high-risk plaques detected by NIRS. Linear regression analysis at the segment level demonstrated an association between the CACS and the total atheroma volume (coefficient, 0.087; 95% CI, 0.024-0.149; P = .008) and the calcific burden (coefficient, 0.117; 95% CI, 0.048-0.186; P = .001), but there was no association between the lipid content or the incidence of high-risk lesions. ConclusionsIn patients with obstructive CAD, the CACS is not associated with the lipid content or plaque phenotypes. These findings indicate that the CACS may have a limited value for screening or stratifying cardiovascular risk in symptomatic patients with a high probability of CAD.

Discrimination of the acute pulmonary embolism subtypes based on the novel MAPH score.

Acute pulmonary embolism (APE) is a thromboembolism situation that can be central or peripheral. APE risk analysis and classification are essential for therapy planning. Our aim is to determine the novel MAPH score (including age, mean platelet volume (MPV), total protein, and hematocrit parameters) that can distinguish APE subtypes. Our retrospective cohort analysis includes 97 APE patients referred to the emergency medicine department who underwent pulmonary computed tomography angiography (CTA) in 24h from 2020 to 2022. The hospital information system provided demographic, clinical, laboratory, and pulmonary CTA data. APE was classified into central (46 patients) and peripheral (51 patients) depending on the area of vascular involvement. The central APE group had higher hypertension (HT) (67.4%) and atrial fibrillation (AF) (39.1%) incidence than the peripheral APE group (all p values > 0.05). The central APE had higher total protein and platelet counts (p = 0.003 and p = 0.036), but peripheral APE had higher troponin values (p = 0.029). Central APE had 2.17 ± 0.85 MAPH and peripheral APE 1.76 ± 0.95 (p = 0.029). HT, AF, platelet count, and MAPH score differed significantly in univariate logistic regression (all p values < 0.05). However, only platelet count varied in multivariate logistic regression (p = 0.042). ROC curve analysis revealed that the MAPH score predicts central APE with 83% sensitivity and 45% specificity at a cut-off level of 1.5. The new MAPH score as an indicator of blood viscosity may distinguish between central and peripheral APE. Our result is significant, especially for centers with limited examinations, as it may accelerate the diagnosis and treatment processes. We think that our results might guide future investigations.

Screening of cardiac allograft vasculopathy in heart transplant patients with coronary computed tomography angiography.

Although coronary angiography (CA) is the gold standard for coronary allograft vasculopathy (CAV) screening, non-invasive modalities have arisen as potential alternatives, such as coronary computed tomography angiography (CCTA). CCTA also quantifies plaque burden, which may influence medical treatment. From January 2021 to April 2022, we prospectively included heart transplant recipients who performed CCTA as a first-line method for CAV detection in a single center. Clinical, CCTA, and CA data were collected. 38 patients were included, 60.5% men, aged 58±14 years. The most frequent cause of transplantation was dilated cardiomyopathy (42.1%), and the median graft duration was 10 years [interquartile range (IQR) 9]. The median left ventricle ejection fraction was 61.5% (IQR 6). The median calcium score was 17 (IQR 231) and 32 patients (84.2%) proceeded to CCTA: 7, 24, and 1 patients had a graded CAV of 0, 1, and 2, respectively. Most patients (37.5%) had both calcified and non-calcified plaques, and the median number of affected segments was 2 (IQR 3). The remaining six patients had extensive coronary calcification, so CA was performed: 4 had CAV1, 1 had CAV2, and 1 had CAV3. During follow-up (12.2±4.2 months), there were neither deaths nor acute coronary syndromes. After CCTA, therapeutic changes occurred in about 10 (26.3%) of patients, mainly related to anti-lipid intensification; such changes were more frequent in patients with diabetes after heart transplant. In this cohort, CCTA led to therapeutic changes in about one-quarter of patients; more studies are needed to assess how CCT may guide therapy according to plaque burden.

Hemodynamic Study of Cerebral Arteriovenous Malformation: Newtonian and Non-Newtonian Blood Flow

ObjectiveArteriovenous malformation is a disease of the vascular system that occurs mainly in the cerebral arteries and spine. Numerical simulation as a powerful method is used to investigate the Cerebral Arteriovenous Malformation hemodynamic after occlusion of the abnormality step by step by embolization. MethodsThe CT Angiographic imaging data of two patients are used and a geometric model is extracted by the Mimics software. Numerical simulation of blood flow is performed in both Newtonian and non-Newtonian models. The Navier–Stokes, and continuity governing equations are solved by finite element method using the COMSOL Multiphysics software (the commercial computational fluid dynamics (CFD) simulation software). To validate the numerical results, the real data on blood flow rate in the feeding artery and draining veins are used, as well as angiographic images at different times. ResultsRegarding the comparison of pressure contours for different occlusions of 0, 30, 50, and 90%, by increasing the amount of occlusion in the nidus, there is an increase in the blood pressure. Regarding the comparison of the blood flow velocity in the feeding artery, draining veins, and inside the AVM nidus for Newtonian and non-Newtonian models, there is a significant difference between these two simulations in vessels with smaller dimensions (such as vessels inside the nidus). ConclusionBy increasing the amount of nidus occlusion, the blood pressure is increased, so the blood supply process is better. According to a significant difference between the Newtonian and non-Newtonian simulations in vessels with smaller dimensions (such as vessels inside the nidus), therefore, non-Newtonian simulation should be done for different occlusions of 30, 50, and 90%.

Abstract TMP50: Deep Learning for Hyperdense Middle Cerebral Artery Detection Using High Resolution CT

Introduction: While CT angiography (CTA) remains the gold-standard for non-invasive diagnosis of large-vessel occlusion (LVO), accurate identification of potential thrombectomy patients on non-contrast CT (NCCT) has many practical workflow benefits. However, current evidence suggests that the hyperdense MCA sign on NCCT is an insensitive marker of LVO. In this study, we hypothesize that high-resolution NCCT (HR-NCCT) greatly increases the sensitivity of the hyperdense MCA sign and that a deep learning model can successfully identify the majority of LVO patients on HR-NCCT. Methods: A retrospective cohort of LVO and non-LVO patients with HR-NCCT (0.5-1.0 mm slice thickness) and CTA imaging was identified. For each patient, the location of a hyperdense MCA was annotated by an expert board-certified neuroradiologist after cross-referencing both HR-NCCT and CTA data. A convolutional neural network (CNN) was developed for localization of hyperdense MCA from HR-NCCT imaging only. In brief, the CNN is a 3D contracting-expanding network (18 layers; 596,364 trainable parameters) optimized with deep supervision and class weights. All model statistics are reported after aggregating results from a five-fold cross-validation. Results: A total of 97 LVO-positive and 110 LVO-negative cases were identified. Of the LVO cases, 81.4% (79/97) contained a hyperdense MCA upon expert review. Using these 79 positive (visible dense MCA) and 110 negative cases for training, the model demonstrated an overall 90.0% accuracy in hyperdense MCA detection (92.9% sensitivity, 88.2% specificity). Overall sensitivity was similar for M1 (91.7%) and M2-M3 (94.7%) occlusions. Additionally, of the 18 LVO cases labeled without a hyperdense MCA by expert review, 5 cases were identified correctly by the model and visually confirmed to match occlusion location on CTA. Conclusion: A deep learning model can identify 80.4% of all CTA-confirmed LVO patients using only HR-NCCT, with sensitivity approaching human experts. Combined with ASPECTS evaluation, NCCT-based imaging triage alone may be sufficient to identify the majority of candidate thrombectomy patients.

The value of computed tomography angiography in predicting the surgical effect and prognosis of severe traumatic brain injury

It is difficult to predict the surgical effect and outcome of severe traumatic brain injury (TBI) before surgery. This study aims to approve an evaluation method of computed tomography angiography (CTA) to predict the effect of surgery and outcome in severe TBI. Between January 2010 and January 2020, we retrospectively reviewed 358 severe TBI patients who underwent CTA at admission and reexamination. CTA data were evaluated for the presence of cerebrovascular changes, including cerebrovascular shift (CS), cerebral vasospasm (CVS), large artery occlusion (LAO), and deep venous system occlusion (DVSO). Medical records were reviewed for baseline clinical characteristics and the relationship between CTA changes and outcomes. Cerebrovascular changes were identified in 247 (69.0%) of 358 severe TBI patients; only 25 (10.12%) of them had poor outcomes, and 162 (65.6%) patients had a good recovery. Eighty-three (23.18%) patients were diagnosed with CVS, 10 (12.05%) had a good outcome, 57 (68.67%) had severe disability and 16 (19.28%) had a poor outcome. There were twenty-six (7.3%) patients who had LAO and thirty-one (8.7%) patients who had DVSO; no patients had good recovery regardless of whether they had the operation or not. Cerebrovascular injuries and changes are frequent after severe TBI and correlate closely with prognosis. CTA is an important tool in evaluating the severity, predicting the operation effect and prognosis, and guiding therapy for severe TBI. Well-designed, multicenter, randomized controlled trials are needed to evaluate the value of CTA for severe TBI in the future.

Clinical application of digital technology in the use of anterolateral thigh lobulated perforator flaps to repair complex soft tissue defects of the limbs.

It is challenging to repair wide or irregular defects with traditional skin flaps, and anterolateral thigh (ALT) lobulated perforator flaps are an ideal choice for such defects. However, there are many variations in perforators, so good preoperative planning is very important. This study attempted to explore the feasibility and clinical effect of digital technology in the use of ALT lobulated perforator flaps for repairing complex soft tissue defects in limbs. Computed tomography angiography (CTA) was performed on 28 patients with complex soft tissue defects of the limbs, and the CTA data were imported into Mimics 20.0 software in DICOM format. According to the perforation condition of the lateral circumflex femoral artery and the size of the limb defect, one thigh that had two or more perforators from the same source vessel was selected for 3D reconstruction of the ALT lobulated perforator flap model. Mimics 20.0 software was used to visualize the vascular anatomy, virtual design and harvest of the flap before surgery. The intraoperative design and excision of the ALT lobulated perforator flap were guided by the preoperative digital design, and the actual anatomical observations and measurements were recorded. Digital reconstruction was successfully performed in all patients before surgery; this reconstruction dynamically displayed the anatomical structure of the flap vasculature and accurately guided the design and harvest of the flap during surgery. The parameters of the harvested flaps were consistent with the preoperative parameters. Postoperative complications occurred in 7 patients, but all flaps survived uneventfully. All of the donor sites were closed directly. All patients were followed up for 13-27months (mean, 19.75months). The color and texture of each flap were satisfactory and each donor site exhibited a linear scar. Digital technology can effectively and precisely assist in the design and harvest of ALT lobulated perforator flaps, provide an effective approach for individualized evaluation and flap design and reduce the risk and difficulty of surgery.

A streamlined controlled-expansion covered tapered stent for TIPS in the treatment of PHT

Transjugular intrahepatic portosystemic shunt (TIPS) relieves cirrhotic complications by reducing portacaval pressure gradient (PCG), but it lacks precision in achieving a targeted post-TIPS PCG simply through diameter adjustment of equal diameter stents. This study aimed to present a controlled-expansion, streamlined, and covered tapered stent, and examined its effects on pressure reduction compared with equal- diameter stents. Twenty-four patients who underwent standardized 8-mm stent TIPS implantation at West China Hospital from December 2017 to February 2021 were included in the current study. Virtual equal-diameter stent graft with different diameter and streamlined tapered stents were created in the post-TIPS 3-dimentional models reconstructed based on computed tomography angiography data. The numerical simulation showed that only two patients achieved targeted post-TIPS PCG consistent with the clinical invasive measurement. When 6-mm and 10-mm equal-diameter stents were employed, simulated post-TIPS PCGs for most patients remained outside the safe range, and recirculating flow was observed at the stent-portal vein anastomosis. In contrast, the use of the new streamlined taper stent resulted in post-TIPS PCGs within the 10–12 mmHg range for 17 out of 24 patients, with no recirculating flow observed at the anastomotic sites. In conclusion, the streamlined tapered stent could pose an effective solution to the problem that the big jump depressurization between two different equal-diameter stents and it would improve the hemodynamics in the region near the PV-stent anchorage. Therefore, the streamlined tapered stent may present a superior alternative for TIPS procedure.

Visualization of Borderline Coronary Artery Lesions by CT Angiography and Coronary Artery Disease Reporting and Data System

Coronary artery disease (CAD) narrows vessel lumens at the sites of atherosclerosis, increasing the risk of myocardial ischemia or infarction. Early and accurate diagnosis of CAD is crucial to significantly improve prognosis and management. CT angiography (CTA) is a noninvasive imaging technique that enables assessment of vascular structure and stenosis with high resolution and contrast. Coronary CTA is useful in the diagnosis of CAD. Recently, the CAD-reporting and data system (CAD-RADS), a diagnostic classification system based on coronary CTA, has been developed to improve intervention efficacy in patients suspected of CAD. While the CAD-RAD is based on CTA, it includes borderline categories where interpreting the coronary artery status solely based on CTA findings may be challenging. This review introduces CTA findings that fall within the CAD-RADS categories that necessitate additional tests to decide to perform invasive coronary angiography and discusses appropriate management strategies.

Coronary stenosis quantification in cardiac computed tomography angiography: multi-factorial optimization of image quality and radiation dose.

The accuracy and variability of quantification in computed tomography angiography (CTA) are affected by the interplay of imaging parameters and patient attributes. The assessment of these combined effects has been an open engineering challenge. In this study, we developed a framework that optimizes imaging parameters for accurate and consistent coronary stenosis quantification in cardiac CTA while accounting for patient-specific variables. The framework utilizes a task-specific image quality index, the estimability index (), approximated by a surrogate estimability polynomial function (EPF) capable of finding the optimal protocol that (1)maximizes image quality with an upper bound for desired radiation dose or (2)minimizes the dose level with a lower bound of acceptable image quality. The optimization process was formulated with the decision variables being subject to a set of constraints. The methodology was verified using CTA data from a prior clinical trial (prospective multi-center imaging study for evaluation of chest pain) by assessing the concordance of its prediction with the trial results. Further, the framework was used to derive an optimum protocol for each case based on the patient attributes, gauging how much improvement would have been possible if the derived optimized protocol would have been deployed. The framework produced results consistent with imaging physics principles with approximated EPFs of 97% accuracy. The feature importance evaluation demonstrated a close match with earlier studies. The verification study found scores closely predicting the cardiologist scores to within 95% in terms of the area under the receiver operating characteristic curve and predicting potential for either an average of fourfold increase in within a targeted dose or a reduction in radiation dose by an average of 57% without reducing the image quality. The protocol optimization framework provides means to assess and optimize CTA in terms of either image quality or radiation dose objectives with its results predicting prior clinical trial findings.

Nonfluoroscopic 3D Image Guidance System Reduces Navigation Times Through Five 3D-Printed Iliofemoral Vascular Phantoms

Purpose: To assess the potential adjunctive role of a 3D electromagnetic (EM) navigational system for use in above-knee vessels afflicted with peripheral artery disease (PAD). Peripheral artery disease can be challenging to operators encountering significant vessel tortuosity, calcium, and stenoses, which may require prolonged procedure times and excessive use of nephrotoxic iodinated contrast when performed with conventional fluoroscopy. Materials and Methods: Following appropriate ethical oversight, five 3D-printed bench phantoms modeling tortuous calcified PAD were created based on source CTA (computed tomography angiography) data sets from real patients. Investigational software was developed based on a commercially available aortic EM navigation platform (Intraoperative Positioning System [IOPS]; Centerline Biomedical, Inc., Cleveland, Ohio), with patient-specific structural maps of vessel lumens and calcification. Using a sensorized prototype 6 French (Fr) catheter and 0.035” guidewire, 15 interventionalists traversed each phantom using the EM platform as well as 2D simulated fluoroscopy-like image guidance and the times were recorded. Participants completed a 10-item standard system usability scale (SUS) questionnaire (score 1–5, 5= strongly agree) evaluating system usability and user satisfaction. Navigation times and SUS scores were compared with a 1-tailed statistical t test. Results: Participants demonstrated a statistically significant reduction in navigation times using EM guidance, performing 0.7 minutes (42 seconds) faster on average ( P &lt; .001), corresponding to a 25% average relative reduction. Participants reported sufficiently high levels of usability satisfaction, with a mean SUS score of 4.29 ( P &lt; .001), exceeding the acceptance criterion (score ≥3.5). Conclusion: This preclinical phantom study highlights the future potential of Centerline Biomedical’s EM navigation technology as a possible adjunct to fluoroscopy for highly precise visualization and navigation of PAD-afflicted vasculature. Clinical Impact This preclinical proof-of-concept study highlights the feasibility of EM navigation not only for branch vessel cannulation, but also for inline navigation of peripheral vessels afflicted with calcified plaques via benchtop iliofemoral phantom simulations. The navigation platform studied addresses the need for improvements in EM technology through modelling algorithms that facilitate 3D visualization of calcified plaque in any projection in real time, in addition to sensorization of both catheter and guidewire in a compact 6Fr system.

Machine-learning score using CCTA and stress CMR for prediction of cardiovascular events in patients with obstructive CAD

Abstract Background In patients with suspected or known coronary artery disease, traditional prognostic risk assessment is based on a limited selection of clinical and imaging findings as coronary computed tomography angiography (CCTA) and stress cardiovascular magnetic resonance (CMR). Machine learning (ML) methods can take into account a greater number and complexity of variables. Purpose To investigate the feasibility and accuracy of ML using stress CMR and CCTA data to predict major adverse cardiovascular events (MACE) in patients with suspected or known coronary artery disease, and compared its performance with existing clinical, CMR or CCTA scores. Methods Between 2008-2020, consecutive symptomatic patients without known CAD referred for CCTA were screened. Patients with obstructive CAD (at least 1 ≥50% stenosis on CCTA) were further referred for stress CMR. Twenty-three clinical, 7 CCTA, and 11 stress CMR parameters were evaluated. ML involved automated feature selection by LASSO, model building with a XGBoost algorithm. The primary composite outcome was MACE defined by cardiovascular death or nonfatal myocardial infarction. The external validation cohort of the ML score was performed in another center (n=274). Results Of 2,210 patients who completed CMR, 2,038 (47% male, mean age 69±12 years) completed follow-up (median 6.8 [IQR 5.9-9.2] years); 281 experienced a MACE (13.8%). The ML score exhibited a higher area under the curve (AUC) compared with ESC risk score, QRISK3 score, Framingham risk score, and CCTA or stress CMR data alone for prediction of MACE (ML score: 0.85 vs ESC score: 0.66, QRISK3 score: 0.64, Framingham score: 0.63, only CCTA score: 0.76, only CMR: 0.82; all p&amp;lt;0.001). Similar results were obtained with AUC of the Precision-Recall (PR) curves (ML score: 0.59 vs. only CCTA score: 0.39, only CMR: 0.45; all p&amp;lt;0.001). The ML score also exhibited a good area under the curve in the external cohort (AUC ROC: 0.85 and AUC PR curve: 0.57). Conclusions The ML score including CCTA and stress CMR data exhibited a higher prognostic value to predict MACE compared with traditional method or traditional scores. In addition, our ML score including CCTA and stress CMR data showed the best performance compared with scores using only CCTA or CMR parameters.ROC et PR curves: ML scorePR curves: ML score

Incremental prognostic value of coronary plaque features on CT angiography in symptomatic patients with obstructive CAD

Abstract Background Several coronary computed tomography angiography (CCTA) studies have shown the strong prognostic value of the coronary artery disease (CAD) burden and the potential interest of the plaque composition analysis. However, the incremental prognostic value of this plaque analysis above the CAD burden in patients with obstructive CAD is not well established. Purpose To assess the incremental prognostic value of the plaque composition analysis using CCTA to predict major adverse cardiovascular events (MACEs) above traditional risk factors and CAD burden in consecutive symptomatic patients with obstructive CAD. Methods In a large multicentric registry, consecutive symptomatic patients without known CAD referred for CCTA were screened between 2008-2020. All patients with obstructive CAD (at least 1 ≥50% stenosis on CCTA) were included. The primary composite outcome was MACE defined by cardiovascular death or nonfatal myocardial infarction. CCTA data were interpreted using multiplanar reconstruction according to the 16-segment coronary artery model. Coronary segments were scored visually for both degree of luminal stenosis and composition of coronary plaque which were classified as noncalcified, mixed, or calcified. To assess the prognostic value of each CCTA findings, different multivariable Cox regression models were used (Model 1: clinical [traditional risk factors]; Model 2: model 1 + CAD burden [number of proximal segments with stenosis ≥50% + number of vessels with obstructive CAD]; Model 3: model 2 + plaques feature [number of segments with noncalcified plaques]). The additional predictive value of each model for predicting MACEs was calculated using C-statistic increment, continuous net reclassification improvement (NRI), and the integrative discrimination index (IDI). Results Of 2,312 patients referred for CCTA, 2,038 (mean age 70±12 years, 46% men) completed follow-up (median 6.7 years; interquartile range: 5.9-9.1 years), and 319 experienced a MACE (14%). After adjustment for traditional risk factors, number of proximal segments with &amp;gt;50% stenosis, number of vessels with obstructive CAD, number of segments with noncalcified were all strongly associated with MACEs (all p&amp;lt;0.001). After adjustment, the addition of the analysis of plaque features (model 3) showed the best improvement in model discrimination and reclassification above a model including traditional risk factors and CAD burden (model 2) (C-statistic improvement=0.03; NRI=45.0%; IDI=9.8%, Chi-2 global=412, all p&amp;lt;0.001; LR-test p&amp;lt;0.001). Conclusions In a large cohort of symptomatic patients with obstructive CAD on CCTA, the analysis of plaque features had an incremental prognostic value to predict MACEs over and above a model combining traditional risk factors and CAD burden.Survival curves for MACEIncremental prognostic value of CCTA

Analysis of the Risk of Basilar Aneurysm Rupture Based on CTA Morphological Parameters

Objective: To investigate morphological risk factors of basilar aneurysm rupture based on computer tomography angiography (CTA) parameters. Materials and methods: The clinical and CTA data of 43 patients with basilar aneurysm admitted to Shaanxi Provincial People’s Hospital from January 2015 to July 2023 were analyzed. The patients were divided into “ruptured group” and “unruptured group,” and the morphological parameters of aneurysms were measured. The general data and morphological parameters between the two groups were statistically analyzed. Logistic regression was used to analyzed statistically significant parameters, and the receiver operating characteristic curve was drawn to evaluate its diagnostic effectiveness. Results: Irregular aneurysms were more likely to rupture than regular aneurysms (x² = 13.971, P &lt; 0.05). The maximum diameter (4.92 [3.37–6.94] mm), length-width ratio (1.31 [1.14–1.55]), height (4.08 [2.71–5.34] mm), aspect ratio (0.99 [0.84–1.45]), and inflow angle (133.63 ± 11.21°) of aneurysms in the ruptured group were larger than the unruptured group, and the differences were statistically significant (P &lt; 0.05). Binary logistic regression showedthat aneurysm shape (OR = 39.347, P = 0.021), length-width ratio (OR = 313.062, P = 0.033), and inflow angle (OR = 1.156, P = 0.004) were independent risk factors for rupture. The area under the curve were 0.809, 0.842. and 0.894, respectively. Conclusion: Aneurysm shape, aspect ratio, and blood flow incidence angle are independent risk factors for basilar aneurysm rupture, which means that they can be used to predict the risk of rupture to a certain extent.

Skin deformation analysis for pre-operative planning of DIEAP flap reconstruction surgery.

Deep inferior epigastric artery perforator (DIEAP) flap reconstruction surgeries can potentially benefit from augmented reality (AR) in the context of surgery planning and outcomes improvement. Although three-dimensional (3D) models help visualize and map the perforators, the anchorage of the models to the patient's body during surgery does not consider eventual skin deformation from the moment of computed tomography angiography (CTA) data acquisition until the position of the patient while in surgery. In this work, we compared the 3D deformation registration from supine arms down (CTA position) to supine with arms at 90° degrees (surgical position), estimating the patient's skin deformation. We processed the data sets of 20 volunteers with a 3D rigid registration tool and performed a descriptive statistical analysis and statistical inference. With 2.45mm of root mean square and 2.89mm of standard deviation, results include 30% cases of deformation above 3mm and 15% above 4mm. Pose transformation deformation indicates that 3D surface data from the CTA scan position differs from data acquired in loco at the surgical table. Such results indicate that research should be conducted to construct accurate 3D models using CTA data to display on the patient, while considering projection errors when using AR technology.

Preliminary experience of CT imaging of the ischaemic brain penumbra through spectral processing of multiphasic CTA datasets

To assess ischaemic penumbra through the post-processing of the spectral multiphasic CT Angiography (mCTA) data in acute ischaemic stroke (AIS) patients. Thirty one consecutive patients strongly suspected of severe Middle Cerebral Artery AIS presenting less than 6 h after onset of symptoms or with unknown time of onset of symptoms underwent a standardized CT protocol in spectral mode including Non Contrast CT, mCTA, and Perfusion CT (CTP) on a dual-layer MDCT system. Areas disclosing delayed enhancement on iodine density (ID) maps were highlighted by subtraction of the serial mCTA datasets. Two neuroradiologists independently rated the correspondence between delayed enhancing areas at mCTA and the penumbral/infarcted areas delineated by two validated CTP applications using a 5-levels scoring scale. Interobserver agreement between observers was evaluated by kappa statistics. Dose delivery was recorded for each acquisition. Averaged correspondence score between penumbra delineation using subtracted mCTA-derived ID maps and CTP ones was 2.76 for one application and 2.9 for the other with best interobserver agreement kappa value at 0.59. All 6 stroke mimics out of the 31 patients’ cohort were correctly identified. Average dose delivery was 7.55 mSv for the whole procedure of which CTP accounted for 39.7%. Post-processing of spectral mCTA data could allow clinically relevant assessment of the presence or absence of ischaemic penumbra in AIS-suspected patients if results of this proof-of-concept study should be confirmed in larger patients’series.

Importance of Preoperative Vertical Geometric Analysis in Surgery for Anterior Communicating Artery Aneurysm.

In this study, we analyzed the vertical geometry of the anterior communicating artery (AComA) complex with the aim to improve the surgical site orientation during aneurysm operations. Further, the geometric data that can contribute to the success of the surgical technique applied for AComA aneurysms are reported. Computed tomography angiography data of the cerebral arteries of 100 patients who visited our clinic were analyzed. A three-dimensional examination was performed according to the Frankfurt horizontal plane (FHP) using the RadiAnt DICOM Viewer (Medixant, Poznan, Poland), and vertical measurements of the AComA complex were calculated. The Willis polygon values were found to be consistent with those in the literature. The mean height of the AComA complex was 30.58 ± 4.80 mm according to the FHP. Preoperative evaluation of the vertical geometry of the AComA complex is essential for AComA aneurysm surgery. The height of the AComA complex is a key parameter affecting intraoperative surgical site visibility. Preoperative calculation of the height of the AComA complex relative to FHP can facilitate intraoperative surgical site orientation.

Using computed tomography angiography and computational fluid dynamics to study aortic coarctation in different arch morphologies.

To study the differences in computed tomography angiography (CTA) imaging of gothic arches, crenel arches, and romanesque arches in children with Aortic Coarctation (CoA), and to apply computational fluid dynamics (CFD) to study hemodynamic changes in CoA children with gothic arch aorta. The case data and CTA data of children diagnosed with CoA (95 cases) in our hospital were retrospectively collected, and the morphology of the aortic arch in the children was defined as gothic arch (n = 27), crenel arch (n = 25) and romanesque arch (n = 43). The three groups were compared with D1/AOA, D2/AOA, D3/AOA, D4/AOA, D5/AOA, and AAO-DAO angle, TAO-DAO angle, and aortic arch height to width ratio (A/T). Computational fluid dynamics was applied to assess hemodynamic changes in children with gothic arches. There were no significant differences between D1/AOA and D2/AOA among gothic arch, crenel arch, and romanesque arch (P > 0.05). The differences in D3/AOA, D4/AOA, and D5/AOA among the three groups were statistically significant (P < 0.05), D4/AOA, D5/AOA of the gothic arch group were smaller than the crenel arch group, and the D3/AOA and D5/AOA of the gothic arch group were smaller than the romanesque arch group (P < 0.05). The difference in AAO-DAO angle among the three groups was statistically significant (P < 0.05), and the AAO-DAO angle of gothic arch was smaller than that of romanesque arch and crenel arch group (P < 0.05). There was no significant difference in the TAO-DAO angle between the three groups (P > 0.05). The difference in A/T values among the three groups was statistically significant (P < 0.05), and the A/T values: gothic arch > romanesque arch > crenel arch (P < 0.05). The CFD calculation of children with gothic arch showed that the pressure drop between the distal stenosis and the descending aorta was 58 mmHg, and the flow rate at the isthmus and descending aorta was high and turbulent. Gothic aortic arch is common in CoA, it may put adverse effects on the development of the aortic isthmus and descending aorta, and its A/T value and AAO-DAO angle are high. CFD could assess hemodynamic changes in CoA.