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Photon-counting detector computed tomography (PCD-CT) has emerged as a revolutionary technology in CT imaging. PCD-CT offers significant advancements over conventional energy-integrating detector CT, including increased spatial resolution, artefact reduction and inherent spectral imaging capabilities. In cardiac imaging, PCD-CT can offer a more accurate assessment of coronary artery disease, plaque characterisation and the in-stent lumen. Additionally, it might improve the visualisation of myocardial fibrosis through qualitative late enhancement imaging and quantitative extracellular volume measurements. The use of PCD-CT in cardiac imaging holds significant potential, positioning itself as a valuable modality that could serve as a one-stop-shop by integrating both angiography and tissue characterisation into a single examination. Despite its potential, large-scale clinical trials, standardisation of protocols and cost-effectiveness considerations are required for its broader integration into clinical practice. This narrative review provides an overview of the current literature on PCD-CT regarding the possibilities and limitations of cardiac imaging.

Objectives: To determine whether coronary computed tomography angiography (CCTA) can improve the diagnostic work-up of patients with acute chest pain and inconclusively high-sensitivity troponins (hs-troponin). Methods: We conducted a prospective, blinded, observational, multicentre study. Patients aged 30–80 years presenting to the emergency department with acute chest pain and inconclusively elevated hs-troponins were included and underwent CCTA. The primary outcome was the diagnostic accuracy of ≥ 50% stenosis on CCTA to identify patients with type-1 non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Results: A total of 106 patients (mean age 65 ± 10, 29% women) were enrolled of whom 20 patients (19%) had an adjudicated diagnosis of type-1 NSTE-ACS. In 45 patients, CCTA revealed non-obstructive coronary artery disease (CAD) or no CAD. Sensitivity, specificity, negative predictive value (NPV), positive predictive value and area-under-the-curve (AUC) of ≥ 50% stenosis on CCTA to identify patients with type 1 NSTE-ACS, was 95% (95% confidence interval: 74–100), 56% (45–68), 98% (87–100), 35% (29–41) and 0.83 (0.73–0.94), respectively. When only coronary segments with a diameter ≥ 2 mm were considered for the adjudication of type 1 NSTE-ACS, the sensitivity and NPV increased to 100%. In 8 patients, CCTA enabled the detection of clinically relevant non-coronary findings. Conclusion: The absence of ≥ 50% coronary artery stenosis on CCTA can be used to rule out type 1 NSTE-ACS in acute chest pain patients with inconclusively elevated hs-troponins. Additionally, CCTA can help improve the diagnostic work-up by detecting other relevant conditions that cause acute chest pain and inconclusively elevated hs-troponins. Clinical relevance statement: Coronary CTA (CCTA) can safely rule out type 1 non-ST-segment elevation acute coronary syndrome (NSTE-ACS) in patients presenting to the ED with acute chest pain and inconclusively elevated hs-troponins, while also dete

Chest pain is a common symptom and can be caused by both cardiac and non-cardiac disorders. Non-invasive diagnostics is increasingly regarded as an essential part of the diagnostic evaluation in patients with chest pain, but inefficient and excessive use must be prevented. This dissertation describes the role of non-invasive diagnostics in patients with acute and chronic chest pain. In short, non-invasive diagnostics: 1) has no role in low risk acute chest pain, 2) can improve selection for invasive heart catheterizations in acute chest pain and suspicion of a heart attack, 3) can identify low risk patients if the test result is "negative" in patients with chronic chest pain, 4) cardiac MRI can identify an acute heart attack.

Background: The aim of this study was to investigate whether speckle-tracking echocardiography (STE) improves the detection of myocardial infarction (MI) over visual assessment of systolic wall motion abnormalities (SWMAs) using delayed enhancement cardiac magnetic resonance imaging as a reference.Methods: Transthoracic echocardiography was performed in 95 patients with first ST segment elevation MI 110 days (interquartile range, 97-171 days) after MI and in 48 healthy control subjects. Two experienced observers independently assessed SWMAs. Separately, longitudinal peak negative, peak systolic, end-systolic, global strain, and strain rate were measured and averaged for the American Heart Association-recommended coronary artery perfusion territories. Receiver operating characteristic analysis was used to determine a single optimal cutoff value for each strain parameter. The diagnostic accuracy of an algorithm combining visual assessment and STE was evaluated.Results: Median infarct size and transmurality were 15% (interquartile range, 7%-24%) and 64% (interquartile range, 46%-78%), respectively. Sensitivity, specificity, and accuracy of visual assessment to detect MI were 74% (95% CI, 63%-82%), 85% (95% CI, 72%-93%), and 78% (95% CI, 70%-84%), respectively. Among the strain parameters, SR had the highest diagnostic accuracy (area under the curve, 0.88; 95% CI, 0.83-0.94; cutoff value, -0.97 sec(-1)). The combination with STE improved sensitivity compared with visual assessment alone (94%; 95% CI, 86%-97%; P <.001), minimally affecting specificity (79%; 95% CI, 65%-89%; P = .607). Overall accuracy improved to 89% (95% CI, 82%-93%; P = .011). Multivariate analysis accounting for age and sex demonstrated that SR was independently associated with MI (odds ratio, 2.0; 95% CI, 1.6-2.7).Conclusions: The sensitivity and diagnostic accuracy of visually detecting chronic MI by assessing SWMAs are moderate but substantially improve when adding STE.

BACKGROUND: Placing the left ventricular (LV) lead at a site of late electrical activation remote from scar is desired to improve cardiac resynchronization therapy (CRT) response. OBJECTIVE: The purpose of this study was to integrate coronary venous electroanatomic mapping (EAM) with delayed enhancement cardiac magnetic resonance (DE-CMR) enabling LV lead guidance to the latest activated vein remote from scar.METHODS: Eighteen CRT candidates with focal scar on DE-CMR were prospectively included. DE-CMR images were semi-automatically analyzed. Coronary venous EAM was performed intraprocedurally and integrated with DE-CMR to guide LV lead placement in real time. Image integration accuracy and electrogram parameters were evaluated offline.RESULTS: Integration of EAM and DE-CMR was achieved using 8.9 +/- 2.8 anatomic landmarks and with accuracy of 4.7 +/- 1.1 mm (mean +/- SD). Maximal electrical delay ranged between 72 and 197ms (57%-113% of QRS duration) and was heterogeneously located among individuals. In 12 patients, the latest activated vein was located outside scar, and placing the LV lead in the latest activated vein remote from scar was accomplished in 10 patients and prohibited in 2 patients. In the other 6 patients, the latest activated vein was located in scar, and targeting alternative veins was considered. Unipolar voltages were on average lower in scar compared to nonscar (6.71 +/- 3.45 mV vs 8.18 +/- 4.02 mV [median +/- interquartile range), PCONCLUSION: Integration of coronary venous EAM with DE-CMR can be used during CRT implantation to guide LV lead placement to the latest activated vein remote from scar, possibly improving CRT.