Computed Tomography Angiography Images Research Articles

Abstract 4137243: Dynamic changes of pericoronary fat attenuation index predicting changes of coronary plaque burden

Background: Percent atheroma volume (PAV) is a validated index of coronary plaque burden, linking to adverse cardiac events. Meanwhile, pericoronary fat attenuation index (FAI) on coronary computed tomography angiography (CCTA) image is a novel prognostic marker of coronary inflammation. Research Questions: It is unknown the impact of coronary inflammation (i.e., FAI) on the progression of coronary PAV in patients at an increased risk of adverse cardiac events. Methods: Patients with type 2 diabetes mellitus (T2DM) who underwent at least two clinically indicated CCTA examinations (time interval > 1 year) at our center were potentially eligible for enrollment. Eligible patients presented with more than one study plaque, defined as non-obstructive stenosis at baseline and not being intervened during serial CCTA. Longitudinal CCTA images were assessed for FAI and compositional plaque characteristics (e.g., PAV) using dedicated post-processing softwares. The relationships between changes in FAI and progression of compositional PAV were examined using the logistic and linear regression analysis. Results: A total of 204 T2DM patients (mean age, 61.2 ± 9.3 years; male, 68.1%) with 366 study plaques were enrolled. All patients were treated with statins, and their time interval between longitudinal CCTAs was 14.1 (12.9, 17.6) months. Compared with patients with improved coronary inflammation (ΔFAI ≤ 0), those with deteriorated coronary inflammation (ΔFAI > 0) had lower high density lipoprotein cholesterol and baseline FAI, whereas higher blood pressure (all p < 0.05). Meanwhile, compared to patients with ΔFAI ≤ 0, those with ΔFAI > 0 had more Δoverall and Δnon-calcified PAV (all p < 0.05). Importantly, these findings were consistent in a dedicated propensity score matching analysis. In logistic regression analysis, ΔFAI > 0 was associated with annual progression of overall PAV and non-calcified PAV, whereas ΔFAI ≤ 0 associated with annual regression of overall PAV and non-calcified PAV after adjusting for cardiac risk factors, baseline PAV and medications (all p < 0.05). Similarly, in linear regression analysis, changes of FAI were independently positively associated with annual changes of overall PAV (β=0.545, p< 0.001) and non-calcified PAV (β=0.461, p< 0.001) (Figure 1). Conclusion: In this longitudinal CCTA study, changes of coronary inflammation are closely correlated with changes of overall and non-calcified PAV among T2DM patients treated with statins.

Diagnostic performance of CCTA and CTP imaging for clinically suspected in-stent restenosis: A meta-analysis

AimsThe objective of this study is to conduct a meta-analysis to assess the diagnostic performance of Coronary Computed Tomography Angiography (CCTA) and a hybrid approach that incorporates Computed Tomography Perfusion (CTP) in addition to CCTA (CCTA ​+ ​CTP) for the detection of in-stent restenosis (ISR), as defined by angiography. MethodsA comprehensive search of articles identified 18,513 studies. After removing duplicates, title/abstract screening, and full-text review, 17 CCTA and 3 CCTA ​+ ​CTP studies were included. Only studies using ≥64-slices multidetector computed tomography (CT) were considered eligible. ResultsThe per-patient ISR prevalence was 43 ​%, with 92 ​% of stents fully interpretable with CCTA. Meta-analysis exhibited a per-stent CCTA (n ​= ​2674) sensitivity of 90 ​% (95 ​% CI; 84–94 ​%), specificity of 89 ​% (95 ​% CI; 86–92 ​%), positive likelihood ratio of 7.17 (95 ​% CI; 5.24–9.61), negative likelihood ratio of 0.17 (95 ​% CI; 0.10–0.25), and diagnostic odds ratio of 45.7 (95 ​% CI; 22.71–82.43). Additional sensitivity analyses revealed no influence of stent diameter or strut thickness on the diagnostic yield of CCTA. The per-stent diagnostic performance of CCTA ​+ ​CTP (n ​= ​752) did not show differences compared to CCTA. ConclusionsWith currently utilized scanners, CCTA and CCTA ​+ ​CTP demonstrated high diagnostic performance for in-stent restenosis evaluation. Consequently, a history of previous stent implantation should not be an argument to preclude using these methods in clinically suspected patients.

Association of coronary inflammation with plaque vulnerability and fractional flow reserve in coronary artery disease

BackgroundThe fat attenuation index (FAI) measured using coronary computed tomography angiography (CCTA) enables the direct evaluation of pericoronary adipose tissue composition and vascular inflammation. We aimed to investigate the association of fractional flow reserve (FFR) and plaque vulnerability with coronary inflammation. MethodsPatients with suspected coronary artery disease (CAD) who underwent CCTA and invasive FFR measurements within 90-day were included. A cloud-based medical device, CaRi-Heart, serves as a surrogate tool for evaluating coronary inflammation based on FAI by analyzing CCTA images. The correlations between CCTA-defined plaque characteristics, invasive coronary angiographic and physiologic assessments, and CaRi-Heart risk were analyzed. The primary endpoint was the patient-oriented composite outcome (POCO) consisting of all-cause death, any myocardial infarction, and any revascularization. ResultsA total of 564 patients (median age 67.0 years; 75.4 ​% men) were included. There were no significant differences in quantitative and qualitative plaque characteristics or FFR between the high- and low-CaRi-Heart risk groups (i.e., ≥5 ​% and <5 ​%). During the median follow-up of 3.2 years [1.13–4.73 years], CaRi-Heart risk ≥5 ​% was associated with a significantly higher rate of POCO compared to CaRi-Heart risk <5 ​% (0.9 ​% vs. 10.1 ​%, P ​= ​0.037). The CaRi-Heart risk was an independent predictor of POCO as a continuous (adjusted HR 1.016, 95 ​% CI 1.005–0.027, P ​= ​0.004) and categorical variable (CaRi-Heart risk ≥5 ​%, adjusted HR 2.949, 95 ​% CI 1.182–7.360, P ​= ​0.021), regardless of high-risk plaque characteristics and FFR. ConclusionCoronary inflammation risk assessed using CaRi-Heart risk provides independent prognostic information regardless of plaque vulnerability and physiologic stenosis in patients with CAD.

Circle of Willis and Its Anatomical Relevance

The Circle of Willis is an arterial network located at the base of the brain, formed by the interconnection of the anterior, middle, and posterior cerebral arteries, along with the anterior and posterior communicating arteries. It connects the internal carotid arteries to the vertebral arteries, allowing the distribution of cerebral blood flow. Its significance lies in its ability to offer an alternative pathway in cases of arterial obstruction, helping to prevent cerebral ischemia. However, anatomical variations of this structure are common, and only 20% to 25% of the population has a "complete" or symmetrical configuration. Such variations can influence the risk of cerebrovascular diseases, such as stroke, as they may compromise the efficiency of the compensatory mechanism. These anatomical variations have a direct impact on the diagnosis and treatment of neurological conditions. The integrity of the Circle of Willis can influence the severity of symptoms in cases of ischemic strokes, as well as affect aneurysm formation and its clinical implications. Advances in imaging techniques, such as CT angiography and magnetic resonance imaging, have enabled more accurate diagnoses and the development of more effective treatments for conditions associated with the Circle of Willis, making its anatomical understanding essential for the prevention and management of cerebrovascular diseases.

Association of sodium-glucose cotransporter-2 inhibitor with regression of coronary plaque burden

Abstract Background Sodium-glucose cotransporter-2 inhibitor (SGLT2i), as a novel oral hypoglycemic therapy of type 2 diabetes mellitus (T2DM), has been proved to benefit cardiac function. However, it remains unknown whether SGLT2i has an impact on coronary plaque characteristics. Purpose The aim of this study was to investigate whether SGLT2i was able to improve coronary plaque composition, burden and inflammation [i.e., fat attenuation index (FAI)] using series coronary computed tomography angiography (CCTA) images among T2DM patients with angina pectoris. Methods T2DM patients presenting with angina pectoris admitted at our center were screened. Eligible patients were those underwent first CCTA within 3 months prior to initiating SGLT2i therapy, and repeated CCTA beyond 6 months after the first CCTA. Those patients not treated with SGLT2i underwent likewise longitudinal CCTA tests were propensity score matching in a 1:1 ratio using age, sex and CCTA time interval. Routine CCTA images were assessed for coronary plaque characteristics using dedicated softwares. Paired or unpaired Student’s t test or Mann–Whitney U test were used for comparing coronary plaque characteristics between series CCTA and patients with or without SGLT2i. The relationships between SGLT2i and changes of plaque characteristics was examined using logistic regression analysis. Results After propensity score matching, a total of 196 T2DM patients with angina pectoris were included (mean age, 60.4±9.2 years; male, 69.9%; SGLT2i treatment, 50%). Time interval between baseline and the last CCTA examinations was 400 (343,496) days. In the SGLT2i group, the non-calcified plaque burden [(39.86±14.30)% vs. (36.84±13.86)%, p=0.002)] and low attenuation non-calcified plaque burden (6.62 [4.11,10.13]% vs. 5.78 [3.40,9.28]%, p=0.042) were significantly decreased between two CCTA images. Whereas, in the non-SGLT2i group, there was no difference with regard to non-calcified and low attenuation non-calcified plaque burden between two CCTA images (all p&amp;gt;0.05). Moreover, changes of total plaque burden and non-calcified plaque burden were higher in the SGLT2i group than the non-SGLT2i group (all p&amp;lt;0.05). Importantly, SGLT2i was associated with total plaque volume (odd ratio=0.594, p=0.024) and non-calcified plaque volume regression (odd ratio=0.619, p=0.042) after adjusting for confounding factors. Conclusion SGLT2i significantly regresses coronary plaque burden, in particularly non-calcified plaque. These findings might explain the observed cardio-protective effect of SGLT2i in large trials.

The impact of hydrostatic pressure on fractional flow reserve in saphenous vein grafts

Abstract Background Intracoronary physiological measurements can be subject to the influence of hydrostatic pressure. Saphenous vein grafts (SVGs) diverge in origin and trajectory from native coronary arteries, which may increase the susceptibility of fractional flow reserve (FFR) measurements to be impacted by the hydrostatic pressures. The precise impact of SVG anatomy on physiological pressure indices remains unknown at present. Purpose We sought to study the impact of SVG anatomy on FFR. Methods Included were symptomatic patients with prior coronary artery bypass grafting and at least one non-occluded SVG, who underwent coronary computed tomography angiography (CCTA) preceding invasive coronary angiography. SVG course and height excursion were reconstructed based on the CCTA images. Similarly to native coronary arteries, the impact of hydrostatic pressure on FFR was calculated by adding 0.077 mmHg to the distal coronary pressure for every millimeter height difference in a supine position between the SVG ostium and the position of the pressure wire tip. Results In total, 74 patients (mean age 71 ± 7 years; 85% male) with 87 SVGs were included. A total of 76 SVGs underwent interrogation by FFR. The height difference between SVG ostium and pressure wire tip position was largest for single SVGs to the circumflex artery (Cx; - 55.1 ± 17.0 mm), followed by sequential SVGs to the Cx (- 53.1 ± 17.7 mm) and to the right coronary artery (RCA; - 36.7 ± 21.6 mm). Corrected FFR was significantly lower as compared to uncorrected FFR in single SVGs to the Cx (0.85 ± 0.17 vs. 0.90 ± 0.18), and sequential SVGs to the Cx (0.92 ± 0.14 vs. 0.96 ± 0.15) and the RCA (0.82 ± 0.20 vs. 0.85 ± 0.21) (P&amp;lt;0.001 for all). Conclusions Hydrostatic pressure related to the course anatomy of SVGs notably affects FFR values, resulting in an overestimation of FFR in SVGs to the Cx and sequential SVGs to the RCA. In these SVGs, FFR values near the cutoff value should be interpreted cautiously.

Relationship between plaque burden and plaque vulnerability in patients with acute coronary syndromes versus chronic coronary syndrome

Abstract Background The relationship between plaque burden and plaque vulnerability based on clinical presentations has not been fully investigated. Objective The aim of this study was to compare the relationship between plaque burden and plaque vulnerability in patients with acute coronary syndromes (ACS) versus chronic coronary syndrome (CCS). Methods This is an observational, single-center cohort study. Patients who underwent both coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) before coronary intervention were enrolled. All OCT and CTA images were analyzed at the core laboratory. All plaques were detected in culprit vessels using CTA, and total plaque volume (TPV) and OCT features were assessed at the corresponding sites. A layered plaque was defined as a plaque with one or more layers of different optical densities and a clear demarcation from underlying components. The layer arc was measured at 1-mm intervals. The layer index, which is equivalent to layer volume, was defined as mean layer arc × layer length. All plaques were divided into three groups according to the tertile range of TPV (low TPV: &amp;lt;96.5 mm3, moderate TPV: 96.5 – 164.7 mm3, high TPV: ≥164.8 mm3). The effect modification of clinical presentations (CCS or ACS) on the association between TPV and OCT features was investigated. Results A total of 990 plaques were imaged by OCT in 419 patients: 445 plaques in 190 (45.3%) patients who presented with ACS and 545 in 229 (54.7%) with CCS. The prevalence of thin-cap fibroatheroma (TCFA) was higher as plaque volume increased in both groups (low vs. moderate vs. high TPV group: 18.4% vs. 37.8% vs. 52.3% in ACS; 16.2% vs. 19.9% vs. 30.6% in CCS; interaction P=0.066). However, the effect modification of clinical presentations on the associations of TPV with macrophage, lipid arc, and layer index was statistically significant. Macrophage was more prevalent in plaques with greater TPV in patients who presented with ACS but not in those who presented with CCS (low vs. moderate vs. high TPV group: macrophage 57.4% vs. 71.8% vs. 82.4% in ACS; 63.4% vs. 67.8% vs. 66.7% in CCS; interaction P=0.004). Lipid arc was more strongly associated with TPV in patients who presented with ACS than in those with CCS (low vs. moderate vs. high TPV group: 116 [76-157] vs. 166 [115-210] vs. 175 [140-221] in ACS; 118 [80-154] vs. 143 [102-187] vs. 150 [102-199] in CCS; interaction P=0.028). Conversely, layer index was more weakly associated with TPV in patients who presented with ACS than in those who presented with CCS (low vs. moderate vs. high TPV group: 0 [0-0] vs. 0 [0-365] vs. 0 [0-903] in ACS; 0 [0-756] vs. 235 [0-1266] vs. 552 [0-1704] in CCS; interaction P=0.046) (Figure 1). Conclusions Greater plaque burden was closely related to the level of plaque vulnerability in ACS, whereas this relationship was less obvious in CCS.Figure 1

CCTA and CTP imaging for detecting clinically suspected in-stent restenosis: a meta-analysis

Abstract Background The evaluation of coronary artery stents via Coronary Computed Tomography Angiography (CCTA) can be compromised by artefacts, potentially undermining its diagnostic accuracy. The integration of CT Perfusion (CTP) with CCTA (CCTA+CTP) has been proposed to enhance the diagnostic yield in detecting in-stent restenosis (ISR). Purpose This meta-analysis aims to assess the diagnostic performance of CCTA and combined CCTA+CTP in detecting ISR. Methods A comprehensive literature search of studies from 2005 to 2022 identified 13,747 articles. Inclusion criteria comprised the utilization of multidetector CT scanners with ≥64 slices and invasive coronary angiography as the reference standard. Studies that systematically evaluated stent patency in asymptomatic patients as part of their protocol were excluded. Results After removing duplicates, screening titles and abstracts, and conducting full-text reviews, 20 studies met the inclusion criteria (17 CCTA, 3 CCTA+CTP). Data on 2,674 CCTA-assessed stents and 752 CCTA+CTP-assessed stents were analyzed. The meta-analysis revealed that CCTA alone achieved a sensitivity of 90% (95% CI; 84-94%) and a specificity of 89% (95% CI; 86-92%)(Figure 1). CCTA+CTP exhibited comparable diagnostic performance, with a per-stent sensitivity of 88% (95% CI; 80-94%) and a specificity of 88% (95% CI; 84-93%) (Figure 2). The summary Receiver Operating Characteristic (sROC) Area Under the Curve (AUC) was 0.96 (95% CI; 0.94-0.97) for CCTA and 0.96 (95% CI; 0.89-1.00) for CCTA+CTP, indicating a high overall performance for both diagnostic modalities. Conclusion Utilizing contemporary imaging hardware, both CCTA and CCTA+CTP demonstrate high diagnostic performance in evaluating ISR. The findings suggest that the presence of coronary artery stents should not preclude the use of these non-invasive diagnostic tests in clinical practice.Figure 1Figure 2

Interscan reproducibility of computed tomography derived coronary plaque volume measurements using a semi-automated analysis software

Abstract Background Coronary computed tomography angiography (CCTA) enables detailed quantification and characterization of coronary atherosclerotic plaque, offering diagnostic and prognostic value. Despite the growing demand for accurate plaque analysis, studies on interscan reproducibility of automated plaque quantification are limited in number and size. Moreover, impact of clinical and technical factors on the reproducibility of plaque assessment tools are scarce. Purpose The objective of this study was to assess the interscan reproducibility of CCTA-derived plaque volume measurements and the implications of clinical and technical characteristics on interscan reproducibility. Methods A total of 101 patients with known coronary artery disease underwent two CCTA scans within hour interval using identical CT acquisition protocol. Coronary plaque volume measurements were quantified on a per-patient level using a contemporary semi-automated plaque analysis software. Results There was no statistically significant difference in median plaque volumes between the first and second scan. The direct correlation was excellent for volumes of non-calcified plaque (NCP), calcified plaque (CP), and total plaque (TP) across all analyses (Pearson’s coefficient 0.96 to 0.99), while moderate for low-density non-calcified plaque (LD-NCP) volumes (Pearson’s coefficient 0.77). Bland Altman analyses demonstrated high interscan agreement with narrow absolute and relative limits of agreement (LoA) across plaque subtypes, except for LD-NCP volumes (Table 1). Interscan reproducibility on CP volumes was affected by CT image quality with narrower LoA in scans with the highest image quality score (p = 0.003), or lowest image reconstructive iteration level (p &amp;lt;0.001). Limits of agreement were significantly narrower for NCP, CP, and TP volumes in lesions located in LAD compared to non-LAD lesions (p &amp;lt;0.001). However, no significant difference in LoA was present when comparing patients according to BMI (&amp;lt;27 and ≥27 kg/m2), heart rate (&amp;lt;65 and ≥65 beats per minute), or Agatston score (&amp;lt;193 and ≥193). Conclusions This comprehensive interscan reproducibility study revealed good agreement in the measurement of plaque subtypes. Adding new insight to existing literature, we have demonstrated that factors such as image quality, image reconstructive algorithms, and lesion location affect the reproducibility of plaque volume measurements. CT-derived plaque quantification using a semi-automated plaque analysis software holds potential for monitoring disease progression or regression in patients with CAD, provided high CCTA image quality.

Influence of coronary plaque characteristics on lesion-specific ischemia assessed by coronary computed tomography angiography and fractional flow reserve - a systematic review and meta-analysis

Abstract Background Characterization of atherosclerotic plaque features by coronary computed tomography angiography (CCTA) carries profound prognostic value. Previous studies indicate that coronary plaque burden and certain plaque features are associated to lesion-specific ischemia by invasive fractional flow reserve (FFR). However, the existing literature is limited by small sample sizes, and provide inconsistent results. Purpose We performed a meta-analysis in order to delineate further the potential association between coronary plaque phenotype by CCTA and FFR. Methods A comprehensive systematic literature review and meta-analysis was conducted. PubMed and Embase databases were searched for studies that investigated the association between coronary plaque characteristics and FFR between January 2010 and August 2023. Study search, evaluation, and data extraction were performed independently by two researchers. Weighted mean difference (WMD) method for WMD was used for comparison of pooled per-lesion plaque parameters and presence of specific plaque features against presence of lesion-specific ischemia (FFR ≤0.80). Lesions with stenosis severity of 25-90% were included. Extracted data from eligible studies were analysed using random effects model for WMD and to estimate odds ratios (OR) with 95% confidence intervals (CI). Results A total of 12 studies were deemed eligible with 1,318 patients and available data on 1,915 coronary lesions. Of these, 626 lesions caused ischemia. Significantly greater total plaque volume (TPV) and non-calcified plaque volume (NCPV) occurred in lesions with abnormal FFR compared to normal FFR (WMD 83.0 mm3, 95% CI: 44.27; 121.81, p&amp;lt;0.001; WMD 83.63 mm3, 95% CI: 55.0; 112.24, p &amp;lt;0.001, respectively). Similar findings were observed for aggregate plaque volume (%APV) and plaque burden (%PB) with WMD 9.18, 95% CI: 6.08; 12.28, p&amp;lt;0.001; WMD 8.83, 95% CI: 4.32; 14.24, p=0.001, respectively. Napkin ring-sign and spotty calcification appeared more frequent in ischemia-causing lesions compared to those with FFR &amp;gt;0.80 (OR 4.25, 95% CI: 1.39; 13.00, p=0.011; OR 1.92, 95% CI: 1.33; 2.75, p=0.001, respectively). A summary of the meta-analysis findings regarding the association between plaque burden and plaque characteristics and FFR is provided in Figure 1 and 2. Conclusion CCTA-derived TPV and NCPV as well as %APV, %PB and the presence of napkin-ring sign and spotty calcification are associated with presence of lesion-specific ischemia. Coronary plaque assessment from CCTA images provide improved discrimination of lesion-specific ischaemia.

Usefulness of FFR-CT to exclude haemodynamically significant lesions in high-risk NSTE-ACS.

Coronary computed tomography angiography (CCTA) and fractional flow reserve (FFR) derived from CCTA (FFR-CT) may provide a means of reducing unnecessary invasive coronary angiography (ICA) in patients with suspected non-ST-elevation acute coronary syndromes (NSTE-ACS). The aim of this study was to evaluate the capacity of FFR-CT and CCTA to rule out significant lesions in high-risk NSTE-ACS patients, using ICA with invasive FFR as the gold standard. High-risk NSTE-ACS patients admitted to 4 European centres were enrolled in this single-arm, prospective core lab-adjudicated study. Patients underwent CCTA with FFR-CT analysis, followed by ICA with invasive FFR. Out of the 250 initially planned NSTE-ACS patients, 168 were included, of whom 151 (92%) had sufficient CCTA image quality to undergo CCTA and FFR-CT analysis. The median high-sensitivity troponin T level at 1 hour post-hospitalisation was 5.3 (interquartile range: 1.8-18.6) times the upper reference limit. At the patient level, the diagnostic performance of FFR-CT was numerically higher as compared to CCTA though not statistically significant (sensitivity: 94% vs 93%, specificity: 63% vs 54%, positive predictive value: 83% vs 79%, negative predictive value: 85% vs 80% and accuracy: 83% vs 79%; p=0.58), suggesting an enhanced capability to avoid unnecessary ICA. At the lesion level, the ability of FFR-CT to detect significant lesions was significantly better than that of CCTA (receiver operating characteristic curves: 0.84 vs 0.65 respectively; p<0.01). In patients with high-risk NSTE-ACS, FFR-CT offers better diagnostic accuracy - though not statistically significant - and a higher ability to rule out haemodynamically significant stenoses as compared to CCTA. This indicates that FFR-CT can reduce unnecessary invasive procedures by more accurately identifying patients requiring further intervention.

Can the radiomics features of intracranial aneurysms predict the prognosis of aneurysmal subarachnoid hemorrhage?

This study attempted to determine potential predictors among radiomics features for poor prognosis in aneurysmal subarachnoid hemorrhage (aSAH), develop models for prediction, and verify their predictive power. In total, 252 patients with aSAH were included in this study and categorized into favorable and poor outcome groups based on the modified Rankin Scale score 3 months after event. Radiomics features of the ruptured intracranial aneurysm extracted from computed tomography angiography images were selected using least absolute shrinkage and selection operator regression and 10-fold cross-validation. A radiomics score was created by selecting the optimal features. Other risk factors for a poor prognosis were screened using multivariate regression analysis. Three models (clinical, aneurysm, and clinical-aneurysm combined models) were developed. The performance of the models was assessed using receiver operating characteristic (ROC) curves. A clinical-aneurysm combined nomogram was constructed to forecast the risk of poor prognosis in patients with aSAH. A total of three clinical variables and six radiomics features were shown to have a significant association with poor prognosis in patients with aSAH. In the training cohort, the clinical, aneurysm, and clinical-aneurysm combined models had areas under the ROC curves of 0.846, 0.762, and 0.893, respectively. In the testing cohort, these models had areas under the ROC curves of 0.848, 0.753, and 0.869, respectively. The radiomics characteristics of ruptured intracranial aneurysms are valuable to predict prognosis after aSAH. The clinical-aneurysm combined model exhibited the best among the three models. The clinical-aneurysm combined nomogram is a reliable and effective tool for predicting poor prognosis in patients with aSAH.

The role of artificial intelligence in coronary CT angiography.

Coronary CT angiography (CCTA) offers an efficient and reliable tool for the non-invasive assessment of suspected coronary artery disease through the analysis of coronary artery plaque and stenosis. However, the detailed manual analysis of CCTA is aburdensome task requiring highly skilled experts. Recent advances in artificial intelligence (AI) have made significant progress toward amore comprehensive automated analysis of CCTA images, offering potential improvements in terms of speed, performance and scalability. This work offers an overview of the recent developments of AI in CCTA. We cover methodological advances for coronary artery tree and whole heart analysis, and provide an overview of AI techniques that have shown to be valuable for the analysis of cardiac anatomy and pathology in CCTA. Finally, we provide ageneral discussion regarding current challenges and limitations, and discuss prospects for future research.

Added prognostic value of fat attenuation index and CT-derived fractional flow reserve over plaque burden in suspected CAD patients without standard modifiable risk factors

Background: In this study, we aimed to investigate the added prognostic value of fat attenuation index (FAI) and CT-derivedfractional flow (CT-FFR) over plaque burden in suspected coronary artery disease (CAD) patients without standard modifiablerisk factors (SMuRFs). Methodology: A total of 260 consecutive suspected CAD subjects without SMuRFs who underwent first coronary computed tomography angiography (CCTA) were retrospectively collected. We calculated FAI, CT-FFR, and segment involvement score (SIS) from CCTA images. Cox regression models were used to assess the incremental prognostic value of FAI and CT-FFR. Results: During a median follow-up of 25.00 months, major adverse cardiovascular events (MACE) were observed in 40 (15.4%) patients. FAI ≥ −70.1, CT-FFR ≤ 0.80, and SIS ≥ 4.5 were associated with the increased rate of MACE (P &lt; 0.0001). FAI did not provide incremental prognostic value over SIS (P = 0.169). Likewise, CT-FFR did not enhance risk prediction (P = 0.159). Combining FAI and CT-FFR added incremental prediction value and improved risk discrimination (P = 0.032; Absolute integrate discrimination improvement (IDI) = 0.070, P &lt; 0.001). Conclusion: In suspected CAD patients without SMuRFs, neither FAI nor CT-FFR independently added incremental prognostic value over plaque burden. Combining FAI and CT-FFR had added prognostic value and improved cardiovascular risk stratification. Keywords: Coronary artery disease; CT-derived fractional flow reserve; fat attenuation index; plaque burden; standard cardiovascularrisk factor; prognosis.

CT-based Intra-thrombus and Peri-thrombus Radiomics for Prediction of Prognosis After Endovascular Thrombectomy: A Retrospective Study Across Two Centers.

Complications from endovascular thrombectomy (EVT) can negatively affect clinical outcomes, making the development of a more precise and objective prediction model essential. This research aimed to assess the effectiveness of radiomic features derived from pre-surgical CT scans in predicting the prognosis post- EVT in acute ischemic stroke patients. This investigation included 336 acute ischemic stroke patients from two medical centers, spanning from March 2018 to March 2024. The participants were split into a training cohort of 161 patients and a validation cohort of 175 patients. Patient outcomes were rated with the mRS: 0-2 for good, 3-6 for poor. A total of 428 radiomic features were derived from intra-thrombus and peri-thrombus regions in non-contrast CT and CT angiography images. Feature selection was conducted using a least absolute shrinkage and selection operator regression model. The efficacy of eight different supervised learning models was assessed using the area under the curve (AUC) of the receiver operating characteristic curve. Among all models tested in the validation cohort, the logistic regression algorithm for combined model achieved the highest AUC (0.87, with a 95% confidence interval of 0.81 to 0.92), outperforming other algorithms. The combined use of radiomic features from both the intra-thrombus and peri-thrombus regions significantly enhanced diagnostic accuracy over models using features from a single region (0.81 vs 0.70, 0.77), highlighting the benefit of integrating data from both regions for improved prediction. The findings suggest that a combined radiomics model based on CT imaging serves as a potent approach to assessing the prognosis following EVT. The logistic regression model, in particular, proved to be both effective and stable, offering critical insights for the management of stroke. AUC=area under the curve; EVT=endovascular thrombectomy; KNN=k-nearest neighbors; LASSO=least absolute shrinkage and selection operator; LightGBM=Light Gradient Boosting Machine; LR=logistic regression; MLP=multi-layer perceptron; RF=random forest; SVM=support vector machine; XGBoost=extreme gradient boosting.

Accuracy of coronary computed tomography angiography-derived quantitative flow ratio for onsite assessment of coronary lesions.

Coronary computed tomography angiography (CCTA)-derived Murray law-based quantitative flow ratio (CT-μFR) is a novel non-invasive method for fast computation of fractional flow reserve (FFR) from CCTA images, yet its diagnostic performance remains to be prospectively validated. We aimed to evaluate the diagnostic performance of onsite CT-μFR in patients with coronary artery disease. This prospective, single-centre trial enrolled patients with ≥1 lesion with 30-90% diameter stenosis on CCTA and planned invasive coronary angiography (ICA) within 30 days. CT-μFR, ICA-derived μFR and FFR were evaluated separately in a blinded fashion. The primary endpoint was the diagnostic accuracy of CT-μFR in identifying patients with haemodynamically significant coronary stenosis defined by the invasive standard: FFR ≤0.80, or μFR ≤0.80 when FFR was not available. Between December 2020 and August 2023, 260 patients were consecutively enrolled. Paired comparison between CT-μFR and the invasive standard was obtained in 706 vessels from 260 patients. The patient-level accuracy of CT-μFR was 89.6% (95% confidence interval [CI]: 85.9-93.4%), which was significantly higher than the prespecified target of 72.0% (p<0.001). Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios for CT-μFR were 93.1%, 86.1%, 87.1%, 92.5%, 6.7, and 0.1, respectively. Out of the 231 vessels investigated by FFR, the accuracy of CT-μFR in vessels without extensive calcification was non-inferior to that of μFR (90.6% vs 88.9%; difference=1.8% [95% CI: -2.8 to 5.5%]; p for non-inferiority<0.001). The study met its prespecified primary endpoint of the diagnostic accuracy of CT-μFR in identifying patients with haemodynamically significant coronary stenosis. CT-μFR was non-inferior to ICA-derived μFR in vessels without extensive calcification. (ClinicalTrials.gov: NCT04665817).

Assessment of Risk Factors for Coronary Artery Disease and Severity by Coronary Computed Tomography Angiography Imaging.

To investigate the correlation between risk factors for coronary stenosis and the degree of coronary artery stenosis based on coronary computed tomography angiography (CCTA). Two hundred seventy-eight patients with coronary artery disease who received treatment in our hospital between January 2020 and January 2021 were selected as the experimental group, and 100healthy people who received physical examination in our hospital during the same period were selected as the control group (age and gender matched with the study group). The clinical data and CCTA data of the two groups of patients were collected and compared. Computed tomography fractional flow reserve (FFRCT) values were calculated based on the CCTA data of the patients in the study group, risk factors for coronary artery stenosis were analysed and the correlation between the risk factors and CT flow reserve fraction was explored. The serum total bilirubin (BIL), apolipoprotein A (apoA), low-density lipoprotein cholesterol (LDL-C), uric acid, total cholesterol (TC) and mean platelet volume levels were higher in the experimental group than in the control group (P < 0.05). Unconditional logistic regression analysis showed that LDL-C, uric acid, TC, triglyceride, serum total BIL and apoA were independent risk factors for coronary heart disease (P < 0.05). Serum total BIL (r = 0.27), apoA (r = -0.30), uric acid (r = -0.48), TC (r = -0.35), triglyceride (r = -0.73) and LDL-C (r = -0.65) showed a negative correlation with FFRCT values (P < 0.05). A positive correlation was detected between high-density lipoprotein cholesterol and FFRCT values (r = 0.37, P < 0.05). Triglycerides, LDL-C, uric acid, TC, serum total BIL and apoA are risk factors for coronary artery stenosis that should be closely monitored and receive active intervention in clinical practice.

Use of a Stroke Alert Protocol and Outcomes at a Quaternary Children’s Hospital

To assess for improvement in diagnostic efficiency following implementation of an institutional pediatric stroke alert protocol at a quaternary children's hospital, and to compare characteristics of in-hospital (IH) and out-of-hospital (OH) stroke alert activations. We retrospectively reviewed data from pediatric stroke alerts called for children between age 1 month to 21 years of age at our quaternary children's hospital between October 2016 and October 2022 after implementation of an institutional stroke alert protocol. Generalized linear models assessed code-to-image (CTI) time over the study period, with and without interaction terms for alert location. Demographic, clinical, and imaging characteristics between IH and OH alerts were compared using Fisher's exact test or Mann-Whitney U test. Of 206 total stroke activations, 129 (62.6%) occurred IH and 77 (37.4%) occurred OH. Overall mean CTI time decreased by 4.56 minutes per year (p = 0.007) after adjusting for confounders. The association between year and mean CTI time was significantly stronger for IH alerts (decrease of 8.33 minutes/year) compared with OH alerts (increase of 1.90 minutes/year). Subgroup analyses showed that CTI for computed tomography (CT) ± CT angiography and magnetic resonance imaging (MRI) without sedation improved, although CTI time for MRI with sedation did not change over time. IH/OH divergent trends were consistent for CT ± CTA and non-sedated MRI. After implementation of a pediatric stroke alert protocol, we observed a steady and significant improvement in CTI times for IH, but not OH alerts.

Extended transcavernous posterior clinoidectomy in endoscopic endonasal surgery.

Mastery of the posterior clinoidectomy technique is of utmost importance for neurosurgeons who specialize in endoscopic endonasal approaches, because the posterior clinoid process (PCP) is commonly involved in chondroid tumor resection. Three main techniques for posterior clinoidectomy have been developed: intradural, extradural, and transcavernous interdural. The authors introduce here a novel technical variant in which the transcavernous approach is extended to the dorsal clinoidal space after transection of the caroticoclinoid ligament, and they elaborate on its clinical application on the basis of anatomical dissections and radiological studies. The authors reviewed CT angiography images and 3D reconstruction of the PCP in 50 adults to analyze the height and presence of ossified ligament attachments. In addition, endoscopic endonasal posterior clinoidectomy was performed in 20 lightly embalmed postmortem human heads. Three techniques, including extradural, transcavernous, and extended transcavernous posterior clinoidectomy, were performed sequentially, and anatomical landmarks and areas exposed with each technique were investigated and compared. Using radiological studies, the authors categorized the PCPs as 1 of 2 types: 1) normal, defined as less than or equal to 8 mm high with no ossified ligament attachments; or 2) complex, defined as greater than 8 mm high with or without an ossified ligament attachment. Compared with extradural (exposed PCP height 4.7 ± 0.5 mm) and transcavernous (exposed PCP height 7.3 ± 0.8 mm) posterior clinoidectomies, the extended transcavernous posterior clinoidectomy provided the maximally exposed PCP height (9.6 ± 0.4 mm; p < 0.0001). This report details the extended transcavernous posterior clinoidectomy as a novel technical variant for achieving maximal exposure of the PCP in endoscopic endonasal surgery. In addition, the positive results establish the importance of preoperative skull base imaging for surgical planning.

Radiomics prediction models of left atrial appendage hypercoagulability based on machine learning algorithms: an exploration about cardiac computed tomography angiography imaging.

Transesophageal echocardiography (TEE) is the standard method for diagnosing left atrial appendage (LAA) hypercoagulability in patients with atrial fibrillation (AF), which means LAA thrombus/sludge, dense spontaneous echo contrast and slow LAA blood flow velocity (< 0.25m/s). Based on machine learning algorithms, cardiac computed tomography angiography (CCTA) radiomics features were adopted to construct prediction models and explore a suitable approach for diagnosing LAA hypercoagulability and adjusting anticoagulation. This study included 652 patients with non-valvular AF. The univariate analysis were used to select meaningful clinical characteristics to predict LAA hypercoagulability. Then 3D Slicer software was adopted to extract radiomics features from CCTA imaging. The radiomics score was calculated using the least absolute shrinkage and selection operator logistic regression analysis to predict LAA hypercoagulability. We then combined clinical characteristics and radiomics scores to construct a nomogram model. Finally, we got prediction models based on machine learning algorithms and logistic regression separately. The area under the receiver operating characteristic curve of radiomics score was 0.8449 in the training set and 0.7998 in the validation set. The nomogram model had a concordance index of 0.838. The final machine-learning based prediction models had good performances (best f1 score = 0.85). Radiomics features of long maximum diameter and high uniformity of Hounsfield unit in left atrial were significant predictors of the hypercoagulable state in LAA, with better predictive efficacy than clinical characteristics. Our combined models based on machine learning were reliable for hypercoagulable state screening and anticoagulation adjustment.