Dual-Energy CT: Current Principles, Clinical Applications, And Future Perspectives

Spectral CT and Photon-counting Detector CT: Principles and Applications in Neuroradiology.

Spectral CT and photon-counting detector (PCD) CT are recent innovations in imaging that have gained increasing use as diagnostic tools. Both modalities leverage advanced detector technologies-PCD CT uses detectors that count individual x-ray photons and measure their energies, while spectral CT separates x-ray energies at dual or multiple levels. These approaches provide higher spatial resolution, improved contrast-to-noise ratio, and reduced noise and enable multienergy imaging from a single acquisition. These techniques enhance visualization of tissue characteristics and reduce artifacts compared with conventional energy-integrating detector CT. This review article introduces the fundamental principles of spectral CT and PCD CT, their advantages in neuro-oncologic applications, and their potential to improve diagnostic imaging through enhanced image quality and quantitative accuracy. Keywords: Physics, CT-Photon-counting, Pediatrics, CT-Spectral © RSNA, 2026.

Photon-Counting Computed Tomography in the Era of Precision Medicine: Technological Advances, Artificial Intelligence Integration, and Multidisciplinary Clinical Applications

Photon-Counting Computed Tomography (PCCT) has emerged as one of the most significant innovations in diagnostic imaging by introducing photon-counting detector technology capable of overcoming several intrinsic limitations of conventional energy-integrating detector computed tomography. This review analyzes the technological principles underlying PCCT, its integration with artificial intelligence, current clinical applications, implementation challenges, and future perspectives in precision medicine. A structured review of the contemporary scientific literature was conducted using internationally recognized biomedical databases and peer-reviewed publications focusing on detector technology, spectral imaging, quantitative imaging biomarkers, radiation dose optimization, and multidisciplinary clinical applications. The reviewed evidence consistently demonstrated that PCCT provides superior spatial resolution, improved contrast-to-noise ratio, enhanced spectral imaging, quantitative tissue characterization, and substantial reduction of electronic noise and beam-hardening artifacts while maintaining lower radiation exposure than conventional CT systems. The greatest clinical benefits were observed in cardiovascular imaging, oncology, neurology, pediatric radiology, pulmonary imaging, abdominal imaging, and musculoskeletal applications. The integration of artificial intelligence further enhances image reconstruction, automated segmentation, lesion detection, radiomics, workflow optimization, and quantitative image analysis, facilitating increasingly individualized diagnostic assessment. Despite important challenges related to acquisition costs, infrastructure requirements, protocol standardization, and broader clinical implementation, the available evidence supports Photon-Counting Computed Tomography as a transformative technology with the potential to redefine diagnostic imaging and strengthen the development of precision medicine across diverse healthcare systems.

WashU Scholarly

Assessing Image Quality Differences Between Single-Energy and Dual-Energy Computed Tomography in Head, Thoracic, and Abdominal Scans: A Systematic Review

Background Computed tomography (CT) is an essential imaging modality for evaluating head, thoracic, and abdominal conditions. High-quality images are crucial for accurate diagnosis and clinical decision-making. Single-energy CT (SECT) is widely used but is limited by beam-hardening artifacts and suboptimal contrast resolution, particularly in complex anatomical regions. Dual-energy CT (DECT) acquires data at two energy levels, allowing spectral analysis that can improve image quality. Objective This article aims to systematically compare image quality between SECT and DECT in head, thoracic, and abdominal CT, focusing on contrast resolution, image noise, artifact reduction, and diagnostic clarity. Materials and Methods A structured literature search was conducted to identify studies directly comparing SECT and DECT. Included studies were analyzed for image quality outcomes across different anatomical regions and clinical tasks, considering the influence of acquisition protocols and reconstruction methods. Results DECT generally improved contrast-to-noise ratio and reduced beam-hardening artifacts, especially in complex or contrast-enhanced regions. However, benefits varied by anatomical area and technical implementation. Optimized SECT protocols often achieved comparable image quality, emphasizing the importance of protocol refinement. Conclusion DECT offers potential advantages over SECT in selected applications, but its performance depends on careful optimization of acquisition and reconstruction parameters. Tailored, evidence-based protocol selection is essential to maximize clinical benefits.

Diagnostic Value and Operational Recommendations for Late Iodine Enhancement and ECV Quantification in Single-Energy Computed Tomography: A Narrative Review

While traditionally focused on coronary anatomy, cardiac computed tomography now enables non-invasive myocardial tissue characterization. By evaluating late iodine enhancement (LIE) and extracellular volume (ECV), single-energy CT (SECT) provides a valuable alternative to cardiac magnetic resonance for assessing ischemic and non-ischemic pathologies. However, clinical implementation of SECT faces technical challenges, primarily the low contrast-to-noise ratio (CNR) of iodine and the reliance on image subtraction for ECV quantification, both of which increase radiation exposure and susceptibility to spatial misregistration. To address these issues, protocol optimization is essential. Evidence-based recommendations include using low tube voltages to shift the X-ray spectrum closer to the iodine K-edge, paired with high reference tube currents. Additionally, delayed acquisition timing should be tailored to specific pathological targets to account for differences in contrast kinetics, and advanced iterative or deep learning image reconstructions should be implemented to mitigate noise. Optimized SECT demonstrates diagnostic and prognostic utility in conditions like acute myocardial infarction, hypertrophic cardiomyopathy, cardiac amyloidosis, and left ventricular thrombus detection. While spectral imaging represents the future, optimizing SECT through technical adjustments and standardized training is crucial for integrating myocardial characterization into routine workflows.

[The role of photon-counting CT technology in the detection of pulmonary diseases].

Computed tomography of the chest is a cornerstone imaging modality in the diagnosis of pulmonary diseases; however, conventional systems based on energy-integrating detectors have inherent physical limitations, including restricted spatial resolution, electronic noise, and reduced image quality at low radiation doses, which may compromise diagnostic accuracy in certain clinical scenarios. Photon-counting detector computed tomography represents a novel technological approach based on the individual detection and energy discrimination of incoming X-ray photons. This enables improved dose efficiency, reduced image noise, higher spatial resolution, and intrinsic spectral imaging from a single acquisition. The aim of this review is to provide an overview of the role of photon-counting detector computed tomography in pulmonary imaging. Based on the available literature, this technology offers particular advantages in the detection and characterization of small pulmonary nodules, subsolid and ground-glass lesions, as well as in the assessment of fine morphological features of interstitial lung diseases. In addition, it improves the visualization of infectious, vascular, and traumatic pulmonary abnormalities. Spectral imaging capabilities, including virtual monoenergetic reconstructions and iodine maps, provide additional functional information on tissue perfusion, lesion characterization, and treatment response. The technique also shows promise in interventional applications by improving the visualization of target lesions and interventional devices. Photon-counting detector computed tomography represents a significant technological advancement in lung imaging. However, its widespread clinical implementation is currently limited by restricted availability, high costs, and challenges related to inter-system comparability. Nevertheless, current evidence suggests that this technology will play an increasingly important role in pulmonary diagnostics in the future. Orv Hetil. 2026; 167(30): 1186-1198.