BACKGROUND:The purpose of this study was to evaluate the accuracy of biventricular and biatrial volume and function measurements by low-dose cardiac cine computed tomography (CT) during recirculation phase of contrast agent with cine cardiac magnetic resonance (CMR) as the reference standard. METHODS:Thirty patients who underwent low-dose cine CT on a third-generation dual-source CT scanner within 30 days of CMR were retrospectively studied. Left and right ventricular (LV, RV) end-diastolic volume (EDV) and end-systolic volume, stroke volume, ejection fraction (EF), and LV mass were measured using the Simpson's method on short-axis images. Left and right atrial (LA, RA) maximum volume, minimum volume, and emptying fraction were measured using the biplane area-length method on 2-chamber and 4-chamber images (LA) and area-length method on 4-chamber images (RA). RESULTS:All low-dose cine CT-derived parameters strongly correlated with those from CMR (r ​= ​0.771-0.974). Mean differences (limits of agreement) between low-dose cine CT and CMR were small for LV EDV (10.0 ​mL [-17.9 to 38.0]), LV EF (-0.4% [-9.5 to 8.6]), and RV EF (0.8% [-7.4 to 8.9]), as well as for atrial volumes and emptying fractions. All low-dose cine CT measurements also showed excellent intra- and inter-rater reproducibility. The median effective radiation dose for the low-dose cine CT was 0.85 ​mSv. CONCLUSION:Low-dose cine CT during recirculation phase of contrast agent provides accurate, reproducible quantification of biventricular and biatrial volume and function compared with cine CMR as the reference, while achieving substantial radiation dose reduction without requiring additional contrast agent.

Background/Objectives: A novel CT dynamic angiographic imaging (CT-DAI) analytic algorithm was evaluated against the clinical gold standard for fractional flow reserve (FFR) measurement in patients with coronary artery disease (CAD) characterized by diffuse dense calcification and previous stent implantation. Methods: This retrospective feasibility study included 24 coronary arteries in 16 patients (age 69.9 ± 8.9 years, 11 males) with CAD who underwent dynamic CT myocardial perfusion scanning using a dual-source CT scanner after intravenous infusion of adenosine triphosphate. The included patients had analyzable proximal and distal coronary artery segments adjacent to the stenosis in the myocardial perfusion images and had corresponding invasive catheter-based FFR measurements for that stenosis. An in-house software based on the CT-DAI algorithm was used to compute FFR using the coronary time-enhancement curves sampled across the stenosis from stress myocardial CT perfusion images. The CT-DAI derived FFR values were then compared to the corresponding catheter-based FFR values. A coronary stenosis was considered functionally significant for FFR values below 0.8. Results: The mean axial length and calcium score of the coronary stenoses were 47.9 mm and 1911.63 Agatston Units, respectively. Eight coronary arteries received stents from previous treatments. The CT-DAI derived FFR values (0.822 ± 0.143) showed an excellent linear correlation (R = 0.974) with and were indifferent from the invasive FFR values (0.826 ± 0.147, p = 0.537), resulting in 100% per-vessel and per-patient sensitivity and specificity for the detection of functionally significant coronary stenosis. Bland-Altman analysis revealed a minimal mean difference in FFR measurements (0.004) between the two modalities with the lower and upper limits of agreement at -0.061 and 0.069, respectively. Conclusions: The findings suggest that CT-DAI can derive FFR for the coronary arteries with heavy calcification and stents from dynamic myocardial CT perfusion images.

Lower thoracic vertebral attenuation measured on coronary artery calcium scoring images may provide an opportunistic computed tomography-based bone health indicator (CT-BHI). This study evaluated the association of CT-BHI with coronary artery disease (CAD) severity and all-cause mortality. We retrospectively analyzed 767 patients with suspected CAD who underwent coronary CT angiography (CCTA) and coronary calcium scoring. Individuals with prior myocardial infarction or revascularization were excluded. CT attenuation was measured in two lower thoracic vertebrae on calcium scoring images, and their mean value was defined as CT-BHI. Patients were categorized into tertiles by CT-BHI (higher, intermediate, lower). The lower CT-BHI group had significantly higher calcium scores (median [IQR]: 146 [4–548]) than the higher (25 [0–277]) and intermediate (39 [0–269]) groups (p < 0.001). CCTA findings revealed a significant difference in CAD severity distribution among the three groups (p = 0.037), with the low CT-BHI group exhibiting a lower prevalence of normal coronary arteries. Combining low CT-BHI with high calcium score enhanced risk stratification (p < 0.05). In multivariate Cox analysis, CT-BHI remained an independent predictor of mortality after adjustment for calcium score (p < 0.05). Adding CT-BHI to calcium scores significantly improved risk classification (continuous net reclassification improvement, 0.263; p = 0.041). CT-BHI derived from routine calcium scoring images may provide a dual-purpose opportunistic marker for integrated cardiovascular and skeletal risk assessment without additional radiation exposure or cost. Further studies are warranted to validate CT-BHI against standardized bone density measurements and determine its role in improving clinical management. Not applicable.

Accurate evaluation of myocardial ischaemia is critical for the management of coronary artery disease (CAD). Quantitative perfusion cardiovascular magnetic resonance (QP-CMR) provides high-resolution assessment of absolute myocardial blood flow (MBF) without ionising radiation. It has demonstrated excellent diagnostic performance for detecting haemodynamically significant CAD, often outperforming visual analysis, particularly in the setting of multi-vessel disease. Similarly, quantitative computed tomography perfusion (CTP) integrates coronary anatomy with functional data and has been shown to significantly improve diagnostic accuracy and specificity over coronary CT angiography alone. This review provides an overview of quantitative myocardial perfusion imaging using CMR and cardiac CT, including their fundamental principles and diagnostic performance. Furthermore, we explore their expanding clinical applications beyond epicardial CAD, such as the evaluation of coronary microvascular dysfunction and non-ischaemic cardiomyopathies, and discuss their advantages and limitations as well as future directions.

BackgroundChildren with a history of Kawasaki disease (KD) and severe coronary involvement are at risk for acute coronary syndrome later in adulthood even in the absence of severe luminal lesions. We therefore investigated whether the coronary vessel walls in such adults are accompanied by potential substrates for acute coronary syndrome using optical coherence tomography (OCT), a high-resolution imaging modality.MethodsOCT was performed in patients who were followed up by serial coronary angiogram (CAG) and cardiac multi-detector computed tomography (MDCT) for ≥ 15 years after the diagnosis of acute KD with coronary artery aneurysms (≥ 6 mm in diameter).ResultsEleven patients (6 males, 55%) with median age 25.3 years (IQR: 22.7-30.3) and median interval 22.6 years (19.9-25.8) after acute KD were recruited. We investigated 51 coronary segments, comprising 43 coronary artery lesions (CALs) (19 regressed aneurysms, 37.2%; 16 persistent aneurysms, 31.4%; and 8 localized stenoses, 15.7%) and 8 normal segments (15.7%). OCT findings revealed fibrocalcific plaque in 20 segments (39.2%), fibroatheroma in 16 (31.4%), superficial signal-rich regions with attenuation in 14 (27.5%), microvessels in 18 (35.3%), luminal thrombi in 13 (25.5%), and ruptured plaque in 4 (7.8%). Qualitatively, all but one normal segment showed no OCT-derived abnormalities, whereas CALs, including regressed aneurysms, exhibited fibrocalcific plaques, fibroatheroma, and microvessels, along with luminal thrombi and ruptured plaques. Quantitatively, CAG-derived advanced lesions (persistent aneurysms and localized stenoses) and MDCT-derived calcified plaques were associated with OCT-detected vessel wall abnormalities.ConclusionsThe present study showed that CALs in adults long after acute KD with severe coronary involvement are associated with OCT-derived vessel wall abnormalities, which are correlated with luminal lesions and MDCT-detected calcified plaques. Although these results do not demonstrate causality and may not be generalizable to milder cases, they warrant further studies to optimize screening and monitoring of adult KD-related coronary sequelae.

For patients with aortic diseases, coronary CT angiography (CCTA) is performed for preoperative evaluation of coronary artery disease, often in combination with CT angiography of thoracic and abdominal aorta (CTAO) within the same examination. A dual-source photon-counting detector CT (PCD-CT) offers advantages including improved dose efficiency and reduction of electronic noise, which might help maintain image quality even at low tube voltages. This study aimed to compare a low-kV one-scan CCTA/CTAO protocol with a low-kV dedicated CCTA followed by a higher-kV CTAO acquisition (separate-scan) regarding radiation dose and image quality. This retrospective, single-center study included 42 patients who underwent CCTA and CTAO using PCD-CT for preoperative CAD screening for aortic disease: 19 had separate-scan, 23 had one-scan CCTA and CTAO. Image quality for CCTA was assessed using a four-point scale (excellent, good, fair, non-diagnostic). Image quality for CTAO was assessed using a five-point scale (excellent, good, moderate, poor, non-diagnostic). Radiation dose was significantly lower in the one-scan group compared to the separate-scan group (mean total dose-length product, 175.8 ± 71.1 vs. 769.4 ± 212.1 mGy·cm; P < 0.001). For CCTA, subjective image quality scores were comparable between the two groups (P = 0.537), although the separate-scan group showed significantly higher objective CNR compared to the one-scan group (P =0.025). For CTAO, the subjective image quality was significantly superior in the one-scan group (P < 0.01), despite comparable CNR between the groups (P = 0.13). The proportions of good or excellent ratings were 97.1

Myocardial delayed enhancement computed tomography (MDE-CT) is an emerging imaging modality for assessing myocardial fibrosis. However, its diagnostic performance is often limited by low contrast resolution and high image noise. Deep learning–based image reconstruction (DLIR) has recently been introduced as a novel method to enhance CT image quality. This study aimed to evaluate whether DLIR improves image quality and diagnostic suitability in MDE-CT, compared to conventional hybrid iterative reconstruction (HIR). A total of 108 patients with visually confirmed myocardial delayed enhancement on CT were included. CT images were reconstructed using both HIR and DLIR. Quantitative image quality metrics included image noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR). Qualitative image quality was independently assessed by two radiologists using a 5-point Likert scale (1 = poor, 5 = excellent), with scores ≥ 3 considered diagnostically suitable. DLIR significantly reduced image noise (median 7.1 Hounsfield unit [HU] vs. 9.2 HU) and improved both CNR (median 3.2 vs. 2.6) and SNR (median 11.7 vs. 9.0) compared to HIR (all p < 0.0001). DLIR increased CNR and SNR by 26.9

PURPOSE:To compare coronary artery calcium (CAC) scores from ultra-low-dose true non-contrast (TNC), virtual non-contrast (VNC), and virtual non-iodine (VNI) images with standard TNC on a dual-source photon-counting detector CT (PCD-CT). METHODS:In this prospective single-center study (January 2025-March 2026), patients underwent standard TNC (sequential, 120 kVp), ultra-low-dose TNC (high-pitch helical, tin-filtered 100 kVp), and coronary CT angiography (CCTA); VNC and VNI images were generated from CCTA. CAC scores and burden categories were evaluated. Correlation and agreement with standard TNC were assessed using Pearson coefficients with Williams' test, Bland-Altman plots, and weighted Cohen's kappa. RESULTS:Seventy-one patients (median age, 75 years; 52 men) were evaluated. Median dose-length product was 7.98, 71.8, and 428 mGy cm for ultra-low-dose TNC, standard TNC, and CCTA, respectively. Ultra-low-dose TNC showed the strongest correlation with standard TNC (r = 0.996), superior to VNI (r = 0.976, P < 0.001) and VNC (r = 0.900, P < 0.001). Agreement in CAC burden categorization was excellent for ultra-low-dose TNC (κ = 0.932) and good for VNI (κ = 0.827), whereas VNC showed moderate agreement (κ = 0.424). VNI had minimal bias (mean difference, -3.9) but wider limits of agreement than ultra-low-dose TNC (-356.5 to 348.6 vs. -163.2 to 105.9). VNC underestimated CAC scores (mean bias, -442.0). CONCLUSION:Ultra-low-dose TNC with dual-source PCD-CT showed excellent agreement with standard TNC while reducing radiation by nearly 90%. VNI was acceptable but less robust, whereas VNC substantially underestimated CAC scores. Ultra-low-dose TNC is a reliable, dose-efficient alternative to standard TNC for CAC scoring.

BACKGROUND:High temporal resolution (TR) in CT is essential for reducing motion artifacts from rapidly moving structures like the heart. Although the conventional impulse method can measure TR, it requires specialized equipment to accelerate a sphere, which limits its practicality. OBJECTIVES:This study aimed to develop and validate a simplified pendulum method for TR measurement and validate that it provides equivalent measurements to the conventional approach. METHODS:TR was measured using the proposed pendulum method and the conventional slingshot method. Fifty scans were acquired for each method at pitch factors (PF) of 0.8 and 1.2. TR was quantified using full width at half maximum (FWHM) and full width at tenth maximum (FWTM). Equivalence was evaluated with the two one-sided tests (TOST). RESULTS:The pendulum method demonstrated statistical equivalence to the slingshot method across all tested parameters. For PF 0.8, the FWHM was 0.55 ​± ​0.03 ​s for the pendulum method versus 0.54 ​± ​0.04 ​s for the slingshot method (TOST, p ​= ​0.005). At PF of 1.2, the FWHM was 0.15 ​± ​0.01 ​s for both methods, which were also statistically equivalent (TOST, p ​= ​0.021). CONCLUSION:The pendulum method provides a simple, reproducible approach for TR measurement, facilitating parameter optimization in clinical and research imaging.

Coronary CT angiography (CCTA) using retrospective helical scanning allows for cardiac function but requires high radiation exposure. This study aimed to investigate the optimal timing and feasibility of low-dose cine CT during the recirculation phase of the contrast agent. We conducted a retrospective analysis of MR perfusion examinations in 38 patients to determine the recirculation timing of the contrast agent, and, based on the findings of the MR perfusion study, a feasibility study of a low-dose cine CT during the recirculation phase was performed for 51 patients with suspected or known coronary artery disease. The MR perfusion study identified approximately 20 s after the contrast peak in the left ventricle (19.5 ± 4.3 HU) as the optimal recirculation time of contrast agent, with no significant correlation between left ventricular function and the timing. In cine CT images, CT values within the left (290.2 ± 42.1 HU) and right (264.1 ± 36.9 HU) ventricles were almost identical during the recirculation phase, with better contrast (p < 0.001) in the right atrium and ventricle compared to first-pass CCTA images. Cine CT showed high inter-rater reliability for left and right ventricular function assessment and better diagnostic performance than echocardiography for myocardial infarction assessment. The combined dose for CCTA (2.0 mSv) and cine CT (0.9 mSv) was 2.9 mSv. A brief cine CT acquisition added to CCTA, timed to contrast recirculation, provides global and regional left ventricular function at a small incremental radiation dose (approximately 1 mSv). This single-visit protocol is a valuable alternative when echocardiography or MRI access is restricted or multiple examinations are not feasible. Question This study aimed to investigate the optimal timing and feasibility of low-dose cine CT during the recirculation phase of the contrast agent. Findings A 20-s recirculation time enabled low-dose cine CT (0.9 mSv) that allowed for effective cardiac function assessment. Clinical relevance When coronary CT is already indicated, a short cine acquisition can provide complementary functional information and may reduce additional testing in selected patients.

Positron emission tomographic myocardial perfusion imaging in conjunction with tracer-kinetic modeling affords the concurrent assessment of myocardial blood flow (MBF) in mL/min/g of tissue. Cardiac magnetic resonance, computed tomography, and echocardiography are emerging technologies capable of MBF quantification. The noninvasive evaluation and quantification of MBF during hyperemia and at rest and corresponding myocardial flow reserve expand the realm of conventional myocardial perfusion imaging from detection of the most advanced, and flow-limiting, epicardial lesions in multivessel coronary artery disease (CAD) to less severe intermediate epicardial lesions, accurate delineation of the extent and severity of ischemic burden in multivessel CAD, detection of diffuse ischemia attributable to CAD or at coronary arteriolar level such as in hypertrophic cardiomyopathy, transplantation vasculopathy, and coronary microvascular dysfunction in its classical and/or endogen forms. Apart from improving the diagnostic scope in ischemic heart disease, the additional quantitation of MBF also affords the contingency to follow-up on treatment success of therapeutic interventions, risk factor modifications, and/or lifestyle changes likely to improve long-term cardiovascular outcomes. Standardized algorithms for each imaging modality in the diagnosis and reporting of ischemia heart disease appear critical for optimized diagnosis and treatment decisions in such patients. In this respect, the convened expert panel strives to provide a concise overview of the pathophysiology of ischemic heart disease and its noninvasive assessment with different imaging modalities that may be pivotal for the diagnosis of various pattern types of ischemic heart disease, as well as individualized and image-guided patient care likely to further optimize cardiovascular outcome.

Background: Assessment of cardiac disease before cancer therapy is crucial, as advancements in cancer treatment have led to prolonged survival and an increase in cardiovascular complications. Specifically, esophageal cancer and heart disease share common risk factors, such as smoking and obesity. Radiation therapy (RT) for esophageal cancer is associated with elevated cardiac radiation exposure. This study aimed to assess the prevalence of coronary artery disease (CAD) in patients with esophageal cancer who were eligible for RT. Methods: We examined the prevalence of coronary artery stenosis, abnormal myocardial perfusion, and late enhancement using pre-RT cardiac computed tomography (CT) data of 41 patients with thoracic esophageal cancer who were referred for RT between January 2017 and June 2023 and had no history of ischemic heart disease. Results: The median age of the 41 patients was 71 years, with 40 patients being male. Cardiac CT identified significant coronary stenosis (≥50% luminal narrowing) in 18 patients (44%), among whom 9 (50%) had severe stenosis, multivessel disease, or myocardial ischemia. Significant stenosis was most frequently observed in the left anterior descending artery (16/18). Late enhancement, indicating myocardial infarction, was observed in seven patients (17%). Interpretation: Patients with esophageal cancer without a history of ischemic heart disease had a high prevalence (44%) of CAD, with half of them having severe stenosis, multivessel disease, or myocardial ischemia. Given the high prevalence of coronary stenosis, pre-treatment cardiac evaluation is crucial for patients with esophageal cancer. Incorporating cardiac CT findings into radiotherapy planning is recommended to optimize patient care.

Photon-counting detector CT (PCD-CT) holds promise for cardiac CT imaging, including the measurement of extracellular volume (ECV), due to its advanced imaging capabilities. The study aimed to compare the protocols with and without additional contrast medium after coronary CT angiography (CCTA) by evaluating (1) the stability of subtraction method-based ECV (ECVSUB) across various keV images and (2) the correlation and agreement of ECVSUB with iodine map-based ECV (ECVIOD). Forty patients with known or suspected coronary artery disease were divided into two groups. In Protocol A (n = 20), only the standard contrast dose for CCTA was administered, while in Protocol B (n = 20), additional contrast medium was given after CCTA. The difference between the largest and smallest ECVSUB among multiple keV images was defined as the variability of ECVSUB. Correlations and agreement between the methods were assessed using Pearson’s correlation coefficient (r), intraclass correlation coefficient (ICC), and Bland–Altman analyses. The mean variability in ECVSUB was significantly higher in Protocol A (3.8 ± 2.1) compared to Protocol B (2.1 ± 0.9) (p = 0.008). In Protocol A, the correlation between ECVSUB and ECVIOD was poor (r = 0.43, p = 0.059) with a low ICC of 0.40. In this group, Bland–Altman analysis showed a mean difference of 3.7 and limits of agreement from −9.4 to 16.8. In Protocol B, a stronger correlation was observed (r = 0.74, p < 0.001) with an ICC of 0.68. In this group, the mean difference was 2.8 with narrower limits of agreement (−4.8 to 10.4). Additional contrast medium is essential for stable myocardial ECV measurements using PCD-CT.

Despite advances in dose-reduction strategies for coronary CT angiography (CCTA), a 2021 regional survey in Mie Prefecture revealed that the 75th percentile CT dose index volume (CTDIvol) remained 48 mGy—lower than Japan’s 2020 diagnostic reference level (66 mGy), yet substantially exceeding international benchmarks ( 25 mGy). Tailored feedback based on Society of Cardiovascular Computed Tomography (SCCT) guidelines was disseminated to each institution in 2022. This study aimed to evaluate the impact of these intervention on cardiac CT practice in Mie Prefecture in 2023. Institutions with 64-row or greater multidetector CT scanners across Mie Prefecture were invited; 17 hospitals ultimately enrolled. Each site provided CCTA scan protocols and radiation dose data from 20 to 30 consecutive patients aged 20–80 years and weighing 50–70 kg. Examinations performed for coronary artery bypass graft evaluation or aortic valve assessment were excluded. Imaging parameters and radiation dose metrics were compared with a 2021 pre-feedback survey. Data from 487 patients (median age: 71 years, 62

Myocardial computed tomography late enhancement (CT-LE) is a valuable modality used for the assessment of myocardial infarction and fibrosis and is effective in detecting latent cardiac amyloidosis. However, the optimal acquisition mode for CT-LE remains unknown. Here, we compared single-energy shuttle mode and DE mode for improving the quality of CT-LE imaging using dual-source CT. Fifteen patients with suspected or known ischemic heart disease underwent CT-LE imaging 5 min after coronary CT in both shuttle and dual-energy (DE) modes. In DE mode, virtual monoenergetic images at various keVs were reconstructed, and extracellular volume (ECV) was quantified using iodine-specific images. For shuttle mode, ECV was assessed by subtracting the volume from pre-contrast images from CT-LE after non-rigid registration. In DE mode, signal-noise-to-ratio was the highest at 70 keV, but it was still lower than that in shuttle mode (p < 0.001). Contrast-noise-to-ratio was the highest on DE mode at 40 keV and was comparable with that in shuttle mode (p = 0.51). Interobserver agreement for infarct detection was higher in shuttle mode (kappa = 0.981) compared to DE mode (kappa = 0.808). Global ECV was comparable between shuttle and DE modes (p = 0.96). However, the coefficient of variation of segmental ECV was significantly lower in shuttle mode (p < 0.001). Shuttle mode CT-LE demonstrates superior image quality, better agreement in infarct detection, and ECV consistency in comparison to DE mode, suggesting its potential as the preferred approach for CT-LE imaging using dual-source CT despite limited z-axis coverage of 10.5 cm. CT late enhancement imaging in shuttle mode provides superior image quality and consistent extracellular volume measurements compared to dual-energy mode, highlighting its potential as the preferred acquisition method for CT late enhancement imaging in dual-source CT.

Myocardial computed tomography (CT) late enhancement (LE) allows assessment of myocardial scarring. Super-resolution deep learning image reconstruction (SR-DLR) trained on data acquired from ultra-high-resolution CT may improve image quality for CT-LE. Therefore, this study investigated image noise and image quality with SR-DLR compared with conventional DLR (C-DLR) and hybrid iterative reconstruction (hybrid IR). We retrospectively analyzed 30 patients who underwent CT-LE using 320-row CT. The CT protocol comprised stress dynamic CT perfusion, coronary CT angiography, and CT-LE. CT-LE images were reconstructed using three different algorithms: SR-DLR, C-DLR, and hybrid IR. Image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and qualitative image quality scores are in terms of noise reduction, sharpness, visibility of scar and myocardial boarder, and overall image quality. Inter-observer differences in myocardial scar sizing in CT-LE by the three algorithms were also compared. SR-DLR significantly decreased image noise by 35