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Computed tomography late enhancement (CT-LE) is emerging as a non-invasive technique for cardiac diagnosis with wider accessibility compared to MRI, despite its typically lower contrast-to-noise ratio. Optimizing CT-LE image quality necessitates a thorough methodology addressing contrast administration, timing, and radiation dose, alongside a robust understanding of extracellular volume (ECV) quantification methods. This review summarizes CT-LE protocols, clinical utility, and advances in ECV measurement through both single-energy and dual-energy CT. It also highlights photon-counting detector CT technology as an innovative means to potentially improve image quality and reduce radiation exposure. TOC Summary This review delineates the principles, protocols, and clinical applications of computed tomography late enhancement, the quantification of extracellular volume using single-energy and multi-energy approaches, and provides an overview of photon-counting detector computed tomography. [ABSTRACT FROM AUTHOR]

Fractional flow reserve (FFR) is currently considered as the gold standard for revascularization decision-making in patients with stable coronary artery disease (CAD). The application of computational fluid dynamics to coronary computed tomography (CT) angiography (CCTA) enables calculation of FFR without additional testing, radiation exposure, contrast medium injection, and hyperemia (FFR CT). Although multiple diagnostic and clinical studies have enriched the scientific evidence, it is still challenging to integrate FFR CT into clinical practice. Both meticulous scientific backgrounds and precise anatomical data derived from CCTA are fundamental for FFR CT computation, and there are numerous factors impacting on FFR CT calculation and interpretation: coronary artery stenosis, calcium, atherosclerosis, luminal volume, and left ventricular myocardial mass. Further, there is a gap that clinicians using FFR CT need to recognize in interpretation of FFR CT results between diagnostic studies and clinical studies. In this review, we summarize multiple evidence related to FFR CT computation and interpretation to refine the FFR CT strategy in patients with stable CAD. [Display omitted] • Fractional flow reserve (FFR) is the gold standard for revascularization in patients with stable coronary artery disease. • Application of computational fluid dynamics to computed tomography (CT) enables non-invasive calculation of FFR (FFR CT). • Numerous factors impact on FFR CT calculation as well as invasive FFR. • There is a gap in interpretation of FFR CT results between diagnostic studies and clinical studies. [ABSTRACT FROM AUTHOR]

Chronic thromboembolic pulmonary hypertension (CTEPH), classified as group 4 pulmonary hypertension (PH), is caused by stenosis and obstruction of the pulmonary arteries by organized thrombi that are incompletely resolved after acute pulmonary embolism. The prognosis of patients with CTEPH is poor if untreated; however, in expert centers with multidisciplinary teams, a treatment strategy for CTEPH has been established, dramatically improving its prognosis. CTEPH is currently not a fatal disease and is the only curable form of PH. Despite these advances and the establishment of treatment approaches, early diagnosis is still challenging, especially for non-experts, for several reasons. One of the reasons for this is insufficient knowledge of the various diagnostic imaging modalities, which are essential in the clinical practice of CTEPH. Imaging modalities should detect the following pathological findings: lung perfusion defects, thromboembolic lesions in pulmonary arteries, and right ventricular remodeling and dysfunction. Perfusion lung scintigraphy and catheter angiography have long been considered gold standards for the detection of perfusion defects and assessment of vascular lesions, respectively. However, advances in imaging technology of computed tomography and magnetic resonance imaging have enabled the non-invasive detection of these abnormal findings in a single examination. Cardiac magnetic resonance (CMR) is the gold standard for evaluating the morphology and function of the right heart; however, state-of-the-art techniques in CMR allow the assessment of cardiac tissue characterization and hemodynamics in the pulmonary arteries. Comprehensive knowledge of the role of imaging in CTEPH enables appropriate use of imaging modalities and accurate image interpretation, resulting in early diagnosis, determination of treatment strategies, and appropriate evaluation of treatment efficacy. This review summarizes the current roles of imaging in the clinical practice for CTEPH, demonstrating the characteristic findings observed in each modality. [Display omitted] • The treatment for chronic thromboembolic pulmonary hypertension (CTEPH) is established, but the diagnosis remains challenging. • Imaging in CTEPH can detect lung perfusion detects and thromboembolic lesions. • Imaging in CTEPH can also detect heart dysfunction. • Appropriate CTEPH imaging allows for early diagnosis and appropriate management. [ABSTRACT FROM AUTHOR]

Cardiovascular computed tomography (CT) angiography has become an established alternative to invasive catheter angiography. However, imaging artifacts due to partial volume effects with current systems hinder accurate evaluation of calcified or stented segments. Increased spatial resolution may allow to overcome these barriers to precise delineation of vascular disease. Recent developments in CT hardware and reconstruction have enabled CT angiography with ultra-high spatial resolution (UHRCT). In this review we aim to describe the methods to achieve greater spatial resolution in CT that are either in clinical or preclinical stage. In addition, we provide an overview of the available clinical evidence including diagnostic accuracy studies supporting improved vascular assessment with this technology. The benefits that can be gleaned from the initial experiences with UHRCT are promising. Using UHRCT, more patients may receive non-invasive characterization of coronary atherosclerosis by overcoming the limitations of current CT spatial resolution in visualizing and quantifying calcified, stented or small diameter segments. UHRCT may potentially impact existing management pathways as well as contribute to better understanding of the underlying pathophysiology of both macro- and microvascular disease. Developments in CT hardware and reconstruction have enabled CT angiography with ultra-high spatial resolution. Using UHRCT, more patients may receive non-invasive characterization of coronary atherosclerosis by overcoming the limitations of current CT spatial resolution in visualizing and quantifying calcified, stented or small diameter segments. UHRCT may enhance existing management pathways and open new research opportunities in patients with vascular pathologies. [Display omitted] [ABSTRACT FROM AUTHOR]

Ischemic heart disease is the most common cause of mortality worldwide. The pathophysiology of myocardial infarction relates to temporal changes of atherosclerotic plaque culminating in plaque rupture, erosion or hemorrhage and the subsequent thrombotic response. Coronary computed tomographic angiography (CCTA) provides the ability to visualize and quantify plaque, and plaque progression can be measured on a per-patient basis by comparing findings of serial CCTA. The Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography IMaging (PARADIGM) registry was established with the objective of identifying patterns of plaque progression in a large population. The registry comprises over 2000 patients with multiple CCTA scans performed at least two years apart. Unlike previous CCTA registries, a semi-automated plaque quantification technique permitting detailed analysis of plaque progression was performed on all patients with interpretable studies. Since the registry was established, 19 peer-reviewed publications were identified, and all are reviewed and summarized in this article. [ABSTRACT FROM AUTHOR]

To evaluate the diagnostic performance of the self-attention-based model, termed variable Vision Transformer (vViT), in the task of predicting the grade of diffuse glioma based on the 2021 World Health Organization (WHO) central nervous system (CNS) tumor classification. This cross-sectional study analyzed adult patients with histopathologically confirmed diffuse glioma, following the 2021 WHO CNS tumor classification. We used age, sex, radiomic features, and four MRI sequences to predict the grade of gliomas. As binary classifications, we constructed three models: 2 vs. 3/4 (326 patients with 1575 grade 2 and 1574 grade 3/4 images), 3 vs. 2/4 (330 patients with 1726 grade 3 and 1726 grade 2/4 images), and 4 vs. 2/3 (333 patients with 3292 grade 4 and 3292 grade 2/3 images). As a multiclass classification, we constructed a 2 vs. 3 vs. 4 model (334 patients with 1575 grade 2, 1575 grade 3, and 1575 grade 4 images). Metrics including accuracy and area under the curve of the receiver operating characteristic (AUC-ROC) were calculated. The highest accuracy and AUC-ROC were 0.84 (95% confidence interval; 0.75–0.93) in multiclass classification (2 vs. 3 vs. 4) and 0.94 (0.88–0.98) in 4 vs. 2/3, respectively. The highest Cohen's κ coefficient between ground truth and the predicted value was 0.54 obtained in the multiclass classification (2 vs. 3 vs. 4). The vViT is a competent multi-modal deep-learning model that can predict the grade of gliomas which were classified based on the 2021 WHO CNS tumor classification. • We developed variable Vision Transformer for multimodal analysis in medicine. • vViT was applied to classifying gliomas by grades using 2021 WHO CNS tumor classification. • The highest accuracy of 0.84 and AUC-ROC of 0.94 were achieved by vViT in grading gliomas. [ABSTRACT FROM AUTHOR]

The role of change in fractional flow reserve derived from CT (FFR CT) across coronary stenoses (ΔFFR CT) in guiding downstream testing in patients with stable coronary artery disease (CAD) is unknown. To investigate the incremental value of ΔFFR CT in predicting early revascularization and improving efficiency of catheter laboratory utilization. Patients with CAD on coronary CT angiography (CCTA) were enrolled in an international multicenter registry. Stenosis severity was assessed as per CAD-Reporting and Data System (CAD-RADS), and lesion-specific FFR CT was measured 2 ​cm distal to stenosis. ΔFFR CT was manually measured as the difference of FFR CT across visible stenosis. Of 4730 patients (66 ​± ​10 years; 34% female), 42.7% underwent ICA and 24.7% underwent early revascularization. ΔFFR CT remained an independent predictor for early revascularization (odds ratio per 0.05 increase [95% confidence interval], 1.31 [1.26–1.35]; p ​< ​0.001) after adjusting for risk factors, stenosis features, and lesion-specific FFR CT. Among the 3 models (model 1 : risk factors ​+ ​stenosis type and location ​+ ​CAD-RADS; model 2 : model 1 ​+ ​FFR CT ; model 3 : model 2 ​+ ​ΔFFR CT), model 3 improved discrimination compared to model 2 (area under the curve, 0.87 [0.86–0.88] vs 0.85 [0.84–0.86]; p ​< ​0.001), with the greatest incremental value for FFR CT 0.71–0.80. ΔFFR CT of 0.13 was the optimal cut-off as determined by the Youden index. In patients with CAD-RADS ≥3 and lesion-specific FFR CT ≤0.8, a diagnostic strategy incorporating ΔFFR CT >0.13, would potentially reduce ICA by 32.2% (1638–1110, p ​< ​0.001) and improve the revascularization to ICA ratio from 65.2% to 73.1%. ΔFFR CT improves the discrimination of patients who underwent early revascularization compared to a standard diagnostic strategy of CCTA with FFR CT , particularly for those with FFR CT 0.71–0.80. ΔFFR CT has the potential to aid decision-making for ICA referral and improve efficiency of catheter laboratory utilization. [ABSTRACT FROM AUTHOR]

This study sought to investigate the impact of low tube voltage scanning heterogeneity of coronary luminal attenuation on plaque quantification and characterization with coronary computed tomography angiography (CCTA). The impact of low tube voltage and coronary luminal attenuation on quantitative coronary plaque remains uncertain. A total of 1,236 consecutive patients (age: 60 ± 9 years; 41% female) who underwent serial CCTA at an interval of ≥2 years were included from an international registry. Patients with prior revascularization or nonanalyzable coronary CTAs were excluded. Total coronary plaque volume was assessed and subclassified based on specific Hounsfield unit (HU) threshold: necrotic core, fibrofatty plaque, and fibrous plaque and dense calcium. Luminal attenuation was measured in the aorta. With increasing luminal HU (<350, 350-500, and >500 HU), percent calcified plaque was increased (16%, 27%, and 40% in the median; P < 0.001), and fibrofatty plaque (26%, 13%, and 4%; P < 0.001) and necrotic core (1.6%, 0.3%, and 0.0%; P < 0.001) were decreased. Higher tube voltage scanning (80, 100, and 120 kV) resulted in decreasing luminal attenuation (689 ± 135, 497 ± 89, and 391 ± 73 HU; P < 0.001) and calcified plaque volume (59%, 34%, and 23%; P < 0.001) and increased fibrofatty plaque (3%, 9%, and 18%; P < 0.001) and necrotic core (0.2%, 0.1%, and 0.6%; P < 0.001). Mediation analysis showed that the impact of 100 kV on plaque composition, compared with 120 kV, was primarily caused by an indirect effect through blood pool attenuation. Tube voltage scanning of 80 kV maintained a direct effect on fibrofatty plaque and necrotic core in addition to an indirect effect through the luminal attenuation. Low tube voltage usage affected plaque morphology, mainly through an increase in luminal HU with a resultant increase in calcified plaque and a reduction in fibrofatty and necrotic core. These findings should be considered as CCTA-based plaque measures are being used to guide medical management and, in particular, when being used as a measure of treatment response. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging [PARADIGM]; NCT02803411) [Display omitted] [ABSTRACT FROM AUTHOR]

• We assessed the diagnostic performance of CMR for CS with CHB. • CMR imaging demonstrate the high diagnostic performance for CS with CHB. • Late gadolinium enhancement in the basal septum might provide the overall best diagnostic performance. Cardiac magnetic resonance (CMR) imaging has become the principal noninvasive imaging modality for the diagnosis of cardiac sarcoidosis (CS) patients. This study aimed to determine the diagnostic performance of CMR imaging for CS in new-onset complete heart block (CHB) patients implanted with magnetic resonance-conditional pacemaker (MRCP). Fifty CHB patients implanted with MRCP were enrolled in this study. Clinical CS was diagnosed if there was a histological diagnosis of extra-cardiac sarcoidosis in patients with CHB based on the consensus statement; clinical CS was the reference standard. The diagnostic performance of CMR sequences, including cine magnetic resonance imaging (MRI), increased T2-weighted signal (T2WS), and late gadolinium enhancement (LGE), for clinical CS was investigated. We also compared the diagnostic performance of CMR sequences between the entire left ventricle (LV) and the basal septum, which involves the electrical pathway of atrioventricular conduction. In total, 8 of the 50 patients with CHB were confirmed to have extra-cardiac sarcoidosis and were diagnosed with clinical CS. The accuracy, sensitivity, and specificity of LGE in the basal septum and entire LV were 94%, 100%, and 93% and 80% (p = 0.023), 100% (p = 1.00), and 76% (p = 0.023), respectively. The accuracy, sensitivity, and specificity of increased T2WS and cine MRI in the basal septum were 94%, 75%, and 98% and 90%, 38%, and 100%, respectively. There was no statistical difference between the entire LV and the basal septum for the diagnostic performance of increased T2WS and cine MRI. CMR can be a diagnostic tool for evaluating clinical CS in patients with CHB implanted with MRCP. LGE in the basal septum might provide the overall best diagnostic performance for clinical CS with CHB. [ABSTRACT FROM AUTHOR]

An optimal system for interpreting fractional flow reserve (FFR) values derived from CT (FFR CT) is lacking. We sought to evaluate performance of three FFR CT measurements in detecting ischemia by comparing them with invasive FFR. For 73 vessels in 50 patients who underwent coronary CT angiography (CCTA) and FFR CT analysis followed by invasive FFR, the greatest diameter stenosis on CCTA, FFR CT difference between distal and proximal to the stenosis (ΔFFR CT), FFR CT 2 cm distal to the stenosis (lesion-specific FFR CT), and the lowest FFR CT in distal vessel tip were calculated. Significant obstruction (≥50% diameter stenosis) and ischemia (lesion-specific FFR CT ≤0.80, the lowest FFR CT ≤0.80, or ΔFFR CT ≥0.12 based on the greatest Youden index) were compared with invasive FFR (≤0.80). Forty (55%) vessels demonstrated ischemia during invasive FFR. On multivariable generalized estimating equations, ΔFFR CT (odds ratio [OR] 10.2, p < 0.01) remained a predictor of ischemia over CCTA (OR 2.9), lesion-specific FFR CT (OR 3.1), and the lowest FFR CT (OR 0.9) (p > 0.05 for all). Area under the curve (AUC) of ΔFFR CT (0.86) was higher than CCTA (0.66), lesion-specific FFR CT (0.71), and the lowest FFR CT (0.65) (p < 0.01 for all). Addition of each FFR CT measure to CCTA showed improvement of AUC and significant net reclassification improvement (NRI): ΔFFR CT (AUC 0.84, NRI 1.24); lesion-specific FFR CT (AUC 0.77, NRI 0.83); and the lowest FFR CT (AUC 0.76, NRI 0.59) (p < 0.01 for all). Compared with diameter stenosis, ΔFFR CT , lesion-specific FFR CT , and the lowest FFR CT improved ischemia discrimination and reclassification, with ΔFFR CT being superior in identifying and discriminating ischemia. [ABSTRACT FROM AUTHOR]

Background: The relationship between body size and cardiovascular events is complex. This study utilized the ADVANCE (Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care) Registry to investigate the association between body mass index (BMI), coronary artery disease (CAD), and clinical outcomes. Methods: The ADVANCE registry enrolled patients undergoing evaluation for clinically suspected CAD who had >30% stenosis on cardiac computed tomography angiography. Patients were stratified by BMI: normal <25 kg/m2, overweight 25–29.9 kg/m2, and obese ≥30 kg/m2. Baseline characteristics, cardiac computed tomography angiography and computed tomography fractional flow reserve (FFRCT), were compared across BMI groups. Adjusted Cox proportional hazards models assessed the association between BMI and outcomes. Results: Among 5014 patients, 2166 (43.2%) had a normal BMI, 1883 (37.6%) were overweight, and 965 (19.2%) were obese. Patients with obesity were younger and more likely to have comorbidities, including diabetes and hypertension (all P <0.001), but were less likely to have obstructive coronary stenosis (65.2% obese, 72.2% overweight, and 73.2% normal BMI; P <0.001). However, the rate of hemodynamic significance, as indicated by a positive FFRCT, was similar across BMI categories (63.4% obese, 66.1% overweight, and 67.8% normal BMI; P =0.07). Additionally, patients with obesity had a lower coronary volume-to-myocardial mass ratio compared with patients who were overweight or had normal BMI (obese BMI, 23.7; overweight BMI, 24.8; and normal BMI, 26.3; P <0.001). After adjustment, the risk of major adverse cardiovascular events was similar regardless of BMI (all P >0.05). Conclusions: Patients with obesity in the ADVANCE registry were less likely to have anatomically obstructive CAD by cardiac computed tomography angiography but had a similar degree of physiologically significant CAD by FFRCT and similar rates of adverse events. An exclusively anatomic assessment of CAD in patients with obesity may underestimate the burden of physiologically significant disease that is potentially due to a significantly lower volume-to-myocardial mass ratio. [ABSTRACT FROM AUTHOR]