Cardiovascular Applications of Photon-Counting CT Technology: A Revolutionary New Diagnostic Step

Role of photon-counting computed tomography in pediatric cardiovascular imaging

Photon-counting computed tomography (PCCT) represents a significant advancement in pediatric cardiovascular imaging. Traditional CT systems employ energy-integrating detectors that convert X-ray photons into visible light, whereas PCCT utilizes photon-counting detectors that directly transform X-ray photons into electric signals. This direct conversion allows photon-counting detectors to sort photons into discrete energy levels, thereby enhancing image quality through superior noise reduction, improved spatial and contrast resolution, and reduced artifacts. In pediatric applications, PCCT offers substantial benefits, including lower radiation doses, which may help reduce the risk of malignancy in pediatric patients, with perhaps greater potential to benefit those with repeated exposure from a young age. Enhanced spatial resolution facilitates better visualization of small structures, vital for diagnosing congenital heart defects. Additionally, PCCT’s spectral capabilities improve tissue characterization and enable the creation of virtual monoenergetic images, which enhance soft-tissue contrast and potentially reduce contrast media doses. Initial clinical results indicate that PCCT provides superior image quality and diagnostic accuracy compared to conventional CT, particularly in challenging pediatric cardiovascular cases. As PCCT technology matures, further research and standardized protocols will be essential to fully integrate it into pediatric imaging practices, ensuring optimized diagnostic outcomes and patient safety.

Trends in Clinical Cardiac Photon-Counting Detector CT Research: A Comprehensive Bibliometric Analysis

Photon-counting detector computed tomography (PCD-CT) represents a significant advancement in radiological imaging, offering substantial potential for cardiac applications that remain partially underexplored. This bibliometric analysis investigates the evolution and current clinical application of cardiac PCD-CT by examining research trends from 2019 to 2024. The analysis aims to understand the development of this technology, its clinical implications, and future directions. A comprehensive literature search was conducted using databases such as PubMed, EMBASE, Scopus, and Google Scholar, yielding 984 records. After removing duplicates and applying inclusion criteria, 81 studies were included in the final analysis. These studies primarily focused on coronary artery calcium scoring, coronary atherosclerotic plaque assessment, and coronary artery stenosis quantification. The findings indicate a significant upward trend in the number of publications, peaking in 2023. The bibliometric analysis revealed that the USA, Germany, and Switzerland are the leading contributors to PCD-CT research, with prominent institutions like the Mayo Clinic and the University of Zurich driving advancements in the field. The NAEOTOM Alpha by Siemens Healthineers, being the only commercially available PCD-CT model, highlights its central role in cardiac imaging studies. Funding for PCD-CT research came from various sources, including industry leaders like Siemens and Bayer, as well as governmental and academic institutions. The analysis also identified several challenges that PCD-CT research faces, including the need for larger patient cohorts and broader geographical representation. In conclusion, the rapid growth of cardiac PCD-CT research underscores its transformative potential in clinical practice. Continued investment, collaboration, and extensive research are essential to fully harness the benefits of PCD-CT.

Cardiac computed tomography for cardiac masses: a necessity or a luxury?

Cardiac masses present a considerable diagnostic challenge because of their diverse causes and potential clinical implications. Traditional imaging methods, such as transthoracic echocardiography and transesophageal echocardiography, are crucial for initial assessments owing to their accessibility, but they have a major limitation represented by inter-operator variability. Therefore, cardiac computed tomography (CT) has become an indispensable adjunct, providing detailed anatomical information and tissue characterization. This review examines the prevalence, categorization and diagnostic benefits of cardiac CT in the evaluation of cardiac masses. The high-resolution imaging and multiplanar features of cardiac CT allow in-depth assessment of the structure, location and enhancement patterns of masses, helping to distinguish benign from malignant masses and guide clinical decision-making. Specific imaging features of benign and malignant tumors, as well as non-neoplastic masses, are discussed, highlighting the role of CT in overall cardiac assessment. This article highlights the importance of CT in surgical preparation, risk assessment and ongoing monitoring, and highlights its effect on improving patients' outcomes. With continued advances in CT technology, the integration of this modality into routine clinical practice should improve the accuracy of diagnosis and management of cardiac masses, strengthening the essential role of cardiac CT as a vital component of contemporary cardiovascular imaging.

Voxelwise characterization of noise for a clinical photon-counting CT scanner with a model-based iterative reconstruction algorithm

BACKGROUND

Photon-counting detector (PCD) technology has the potential to reduce noise in computed tomography (CT). This study aimed to carry out a voxelwise noise characterization for a clinical PCD-CT scanner with a model-based iterative reconstruction algorithm (QIR).

METHODS

Forty repeated axial acquisitions (tube voltage 120 kV, tube load 200 mAs, slice thickness 0.4 mm) of a homogeneous water phantom and CTP404 module (Catphan-504) were performed. Water phantom acquisitions were also performed on a conventional energy-integrating detector (EID) scanner with a sinogram/image-based iterative reconstruction algorithm, using similar acquisition/reconstruction parameters. For smooth/sharp kernels, filtered back projection (FBP)- and iterative-reconstructed images were obtained. Noise maps, non-uniformity index (NUI) of noise maps, image noise histograms, and noise power spectrum (NPS) curves were computed.

RESULTS

For FBP-reconstructed images of water phantom, mean noise was (smooth/sharp kernel) 11.7 HU/51.1 HU and 18.3 HU/80.1 HU for PCD-scanner and EID-scanner, respectively, with NUI values for PCD-scanner less than half those for EID-scanner. Percentage noise reduction increased with increasing iterative power, up to (smooth/sharp kernel) 57.7%/72.5% and 56.3%/70.1% for PCD-scanner and EID-scanner, respectively. For PCD-scanner, FBP- and QIR-reconstructed images featured an almost Gaussian distribution of noise values, whose shape did not appreciably vary with iterative power. Noise maps of CTP404 module showed increased NUI values with increasing iterative power, up to (smooth/sharp kernel) 15.7%/9.2%. QIR-reconstructed images showed limited low-frequency shift of NPS peak frequency.

CONCLUSION

PCD-CT allowed appreciably reducing image noise while improving its spatial uniformity. QIR algorithm decreases image noise without modifying its histogram distribution shape, and partly preserving noise texture.

RELEVANCE STATEMENT

This phantom study corroborates the capability of photon-counting detector technology in appreciably reducing CT imaging noise and improving spatial uniformity of noise values, yielding a potential reduction of radiation exposure, though this needs to be assessed in more detail.

KEY POINTS

First voxelwise characterization of noise for a clinical CT scanner with photon-counting detector technology. Photon-counting detector technology has the capability to appreciably reduce CT imaging noise and improve spatial uniformity of noise values. In photon-counting CT, a model-based iterative reconstruction algorithm (QIR) allows decreasing effectively image noise. This is done without modifying noise histogram distribution shape, while limiting the low-frequency shift of noise power spectrum peak frequency.

A Review of Photon-Counting Computed Tomography (PCCT) in the Diagnosis of Cardiovascular Diseases

Photon-counting computed tomography (PCCT) is an innovative mechanism used for imaging and provides higher spatial resolution and contrast sensitivity in comparison with the orthodox energy-integrating detectors (EIDs). Unlike EID-based CT systems, which indirectly convert X-ray photons to electrical signals, PCCT directly counts and quantifies each photon's energy, enhancing image quality and material separation. With all of these features, PCCT is especially useful for cardiovascular imaging, where it is essential to precisely observe cardiac tissues, vascular structures, and coronary arteries. Around the globe, cardiovascular diseases (CVDs) continue to be the primary cause of morbidity and death, and early, precise diagnosis is essential for effective management. This review examines the role of PCCT in diagnosing CVDs, highlighting its enhanced capabilities in improving the precision in diagnosis as well as patient outcomes compared to conventional CT methods. While current evidence supports PCCT's advantages, further research is necessary to validate these findings and facilitate its broader clinical adoption.

Photon-Counting Computed Tomography Angiography of Carotid Arteries: A Topical Narrative Review with Case Examples

Photon counting computed tomography (PCCT) represents a paradigm shift from conventional CT imaging, propelled by a new generation of X-ray detectors capable of counting individual photons and measuring their energy. The first part of this narrative review is focused on the technical aspects of PCCT and describes its key advancements and benefits compared to conventional CT but also its limitations. By synthesizing the existing literature, the second part of the review seeks to elucidate the potential of PCCT as a valuable tool for assessing carotid artery disease. Thanks to the enhanced spatial resolution and image quality, PCCT allows for an accurate evaluation of carotid luminal stenosis. With its ability to finely discriminate between different tissue types, PCCT allows for detailed characterization of plaque morphology and composition, which is crucial for assessing plaque vulnerability and the risk of cerebrovascular events.

Technical principles, benefits, challenges, and applications of photon counting computed tomography in coronary imaging: a narrative review

Background and Objective

The introduction of photon-counting computed tomography (PCCT) represents the most recent groundbreaking advancement in clinical computed tomography (CT). PCCT has the potential to overcome the limitations of traditional CT and to provide new quantitative imaging information. This narrative review aims to summarize the technical principles, benefits, and challenges of PCCT and to provide a concise yet comprehensive summary of the applications of PCCT in the domain of coronary imaging.

Methods

A review of PubMed, Scopus, and Google Scholar was performed until October 2023 by using relevant keywords. Articles in English were considered.

Key Content and Findings

The main advantages of PCCT over traditional CT are enhanced spatial resolution, improved signal and contrast characteristics, diminished electronic noise and image artifacts, lower radiation exposure, and multi-energy capability with enhanced material discrimination. These key characteristics have made room for improved assessment of plaque volume and severity of stenosis, more precise assessment of coronary artery calcifications, also preserved in the case of a reduced radiation dose, improved assessment of plaque composition, possibility to provide details regarding the biological processes occurring within the plaque, enhanced quality and accuracy of coronary stent imaging, and improved radiomic analyses.

Conclusions

PCCT can significantly impact diagnostic and clinical pathways and improve the management of patients with coronary artery diseases (CADs).

Charting the Unseen: How Non-Invasive Imaging Could Redefine Cardiovascular Prevention

Cardiovascular diseases (CVDs) remain a major global health challenge, leading to significant morbidity and mortality while straining healthcare systems. Despite progress in medical treatments for CVDs, their increasing prevalence calls for a shift towards more effective prevention strategies. Traditional preventive approaches have centered around lifestyle changes, risk factors management, and medication. However, the integration of imaging methods offers a novel dimension in early disease detection, risk assessment, and ongoing monitoring of at-risk individuals. Imaging techniques such as supra-aortic trunks ultrasound, echocardiography, cardiac magnetic resonance, and coronary computed tomography angiography have broadened our understanding of the anatomical and functional aspects of cardiovascular health. These techniques enable personalized prevention strategies by providing detailed insights into the cardiac and vascular states, significantly enhancing our ability to combat the progression of CVDs. This review focuses on amalgamating current findings, technological innovations, and the impact of integrating advanced imaging modalities into cardiovascular risk prevention, aiming to offer a comprehensive perspective on their potential to transform preventive cardiology.

Potential Benefits of Photon-Counting CT in Dental Imaging: A Narrative Review

Background/Objectives: Advancements in oral imaging technology are continually shaping the landscape of dental diagnosis and treatment planning. Among these, photon-counting computed tomography (PCCT), introduced in 2021, has emerged as a promising, high-quality oral technology. Dental imaging typically requires a resolution beyond the standard CT systems achievable with the specialized cone-beam CT. PCCT can offer up to 100 µm resolution, improve soft-tissue contrast, and provide faster scanning times, which are crucial for detailed dental diagnosis and treatment planning. Using semiconductor detectors, PCCT produces sharper images and can potentially reduce the number of scans required, thereby decreasing patient radiation exposure. This review aimed to explore the potential benefits of PCCT in dental imaging. Methods: This review analyzed the literature on PCCT in dental imaging from January 2010 to February 2024, sourced from PubMed, Scopus, and Web of Science databases, focusing on high-resolution, patient safety, and diagnostic efficiency in dental structure assessment. We included English-language articles, case studies, letters, observational studies, and randomized controlled trials while excluding duplicates and studies unrelated to PCCT's application in dental imaging. Results: Studies have highlighted the superiority of PCCT in reducing artifacts, which are often problematic, compared to conventional CBCT and traditional CT scans, due to metallic dental implants, particularly when used with virtual monoenergetic imaging and iterative metal artifact reduction, thereby improving implant imaging. This review acknowledges limitations, such as the potential for overlooking other advanced imaging technologies, a narrow study timeframe, the lack of real-world clinical application data in this field, and costs. Conclusions: PCCT represents a promising advancement in dental imaging, offering high-resolution visuals, enhanced contrast, and rapid scanning with reduced radiation exposure.

Photon-Counting Detector Computed Tomography (PCD-CT): A New Era for Cardiovascular Imaging? Current Status and Future Outlooks

Photon-counting detector computed tomography (PCD-CT) represents a revolutionary new generation of computed tomography (CT) for the imaging of patients with cardiovascular diseases. Since its commercial market introduction in 2021, numerous studies have identified advantages of this new technology in the field of cardiovascular imaging, including improved image quality due to an enhanced contrast-to-noise ratio, superior spatial resolution, reduced artifacts, and a reduced radiation dose. The aim of this narrative review was to discuss the current scientific literature, and to find answers to the question of whether PCD-CT has yet led to a true step-change and significant progress in cardiovascular imaging.

Spectral Photon-Counting Computed Tomography: Technical Principles and Applications in the Assessment of Cardiovascular Diseases

Spectral Photon-Counting Computed Tomography (SPCCT) represents a groundbreaking advancement in X-ray imaging technology. The core innovation of SPCCT lies in its photon-counting detectors, which can count the exact number of incoming x-ray photons and individually measure their energy. The first part of this review summarizes the key elements of SPCCT technology, such as energy binning, energy weighting, and material decomposition. Its energy-discriminating ability represents the key to the increase in the contrast between different tissues, the elimination of the electronic noise, and the correction of beam-hardening artifacts. Material decomposition provides valuable insights into specific elements' composition, concentration, and distribution. The capability of SPCCT to operate in three or more energy regimes allows for the differentiation of several contrast agents, facilitating quantitative assessments of elements with specific energy thresholds within the diagnostic energy range. The second part of this review provides a brief overview of the applications of SPCCT in the assessment of various cardiovascular disease processes. SPCCT can support the study of myocardial blood perfusion and enable enhanced tissue characterization and the identification of contrast agents, in a manner that was previously unattainable.

Introduction to Special Issue Imaging in Cancer Diagnosis

In the field of oncology, the precision of cancer imaging is the cornerstone of oncological patient care [...].