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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.
Opmerkingen
Simran Sharma and Marie-Julie Lemmens contributed equally to this work and share first authorship.
Alexander Hirsch and Casper Mihl contributed equally as senior authors and share last authorship.
Introduction
Photon-counting detector computed tomography (PCD-CT) is a new CT imaging technique that will likely reshape the cardiac imaging landscape (Fig. 1; [1]). The primary innovation of PCD-CT lies in its detector technology, which significantly differs from that used in conventional energy-integrating detectors (EID-CT) [1‐3]. Figure 2 provides a schematic overview of EID and PCD technology and an overview of the benefits, alongside their potential clinical implications, and the disadvantages of PCD-CT.
Fig. 1
Infographic: Photon-counting detector computed tomography in cardiac imaging
Fig. 2
Overview of energy-integrating versus photon-counting detector. The energy-integrating detector uses a scintillator (e.g. gadolinium oxysulfide) to absorb X‑rays and convert them into visible light, which is then detected and converted into electrical signals by photodiodes. The photon-counting detector (PCD) uses a Cadmium Telluride/Cadmium Zinc Telluride or Silicon detector to directly convert incoming X‑rays into a charge cloud of electrons, which are collected by pixelated anodes. The electronic signals’ varying colours indicate the different energy levels of the photons, highlighting PCD’s energy-resolving capability
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A key feature of PCD-CT technology is the use of smaller detector elements which enhances spatial resolution. Consequently, it facilitates high-resolution imaging with slice thicknesses down to 0.2 mm, while EID-CT systems typically offer slice thicknesses of 0.6 mm [4]. Secondly, PCD-CT enhances spectral imaging beyond what is achievable with conventional CT systems [5]. By counting individual incoming photons and measuring their energy, the detector can categorise these photons into various energy bins. This process allows better X‑ray photon energy separation compared with conventional EID-based dual-energy CT, improving differentiation of tissue types and materials. It also facilitates advanced image reconstructions including virtual non-iodine (VNI) images and virtual non-calcium images derived from contrast-enhanced scans, as well as virtual mono-energetic images (VMIs) [5]. For a detailed description of the principles of spectral imaging, we refer to a comprehensive review by Danad et al. [6].
All major vendors are currently developing PCD-CT systems and have reported on applications in humans [7‐9]. However, only one system (NAEOTOM Alpha, Siemens Healthineers) is currently commercially available [3].
In line with these advancements, the adoption of PCD-CT is becoming increasingly prominent in cardiac imaging. In the Netherlands, this development is particularly evident now the commercially available PCD-CT systems (NAEOTOM Alpha, Siemens Healthineers) are installed or being installed, along with the upcoming introduction of another prototype scanner from Canon Inc. Reflecting the growing interest in PCD technology within the Dutch radiology and cardiology community, this review elaborates on the specific applications, potential benefits and limitations of PCD-CT in the context of cardiac diseases.
Coronary artery disease
Coronary calcium scoring
Coronary artery calcium (CAC) scoring, typically quantified using the Agatston method on non-enhanced CT scans (with a slice thickness of 2.5–3 mm), serves as an indicator of coronary atherosclerosis and predicts cardiovascular events [10, 11]. A phantom study by Van der Werf et al. demonstrated that CAC scores obtained through routine clinical scan protocols are similar between conventional CT and PCD-CT [12]. Notably, the increased spatial resolution of PCD-CT facilitates improved detectability and more accurate estimation of CAC volumes, especially at reduced slice thicknesses (< 1 mm) [12]. This enhanced resolution may allow the detection of even minute calcifications. However, with the ongoing advancements in CT technology, an important consideration that arises is the clinical relevance of identifying very small calcifications and how this affects patient management and outcomes.
In addition to enhanced detectability, PCD-CT technology could potentially obviate the need for non-contrast scans to determine CAC scores. The ability to perform CAC scoring based on contrast-enhanced coronary CT angiography (CCTA) offers benefits such as reduced scan time and an expected decrease in radiation dose, especially since CAC scoring usually requires a higher kV setting. With the introduction of spectral imaging techniques, various studies have explored algorithms for estimating CAC scores from virtual non-contrast (VNC) images derived from contrast-enhanced images, which are generated from two-material decomposition into water and iodine [13‐15]. Nonetheless, this approach has been consistently found to underestimate CAC scores and even cause false negatives, raising concerns about its clinical utility [13, 14].
To address this limitation, a novel algorithm was introduced that removes iodine from the contrast-enhanced scans, leaving only calcium in the resulting VNI images [16]. A patient study conducted by Emrich et al. revealed that VNI images outperform VNC images in the accuracy of CAC quantification; however, a significant underestimation of CAC scores persisted in VNI reconstructions [16]. Similarly, Sharma et al. reported a superior performance of VNI reconstructions compared with VNC [17]. Conversely, in their study, VNI reconstructions overestimated the CAC scores. Discrepancies in results may stem from variances in software versions and reconstruction methods for VNC and VNI images.
Currently, neither VNC nor VNI reconstructions are reliable enough to completely replace traditional non-contrast acquisition for CAC scoring. While VNI reconstructions might eventually eliminate the need for non-contrast enhanced calcium scoring, further optimisation is necessary for the clinical implementation of these algorithms. Figure 3a illustrates CAC scoring using PCD-CT.
Fig. 3
Advanced coronary artery disease assessment using photon-counting detector CT (PCD-CT). a Calcium artery calcium scoring using PCD-CT on contrast-enhanced, true non-contrast, virtual non-iodine and virtual non-contrast images. The calcified plaque in the left anterior descending (LAD) artery appears more pronounced on the virtual non-iodine image and less pronounced on the virtual non-contrast image, relative to the true non-contrast image. b Ultra-high resolution imaging of coronary arteries in a 66-year-old man with stable angina and multiple risk factors. (a) Multiplanar reformatted (MPR) images of the LAD, depicting extensive calcification of the vessel wall. MPR and cross-sectional views reveal no significant stenosis in the proximal and mid-LAD. (b) MPR images of the LAD with cross-sectional views illustrate significant lumen tapering in the transition from the mid to distal LAD. (c) Invasive coronary angiography confirms the presence of significant stenosis in the mid/distal LAD. c Stent-imaging using ultra-high resolution PCD-CT. Coronary CT angiography of a 67-year-old male patient with typical chest pain was performed using PCD-CT in ultra-high resolution mode. The patient has a history of stent placement in the LAD and left circumflex (LCX) artery. Multiplanar reconstruction images display a patent stent in the LCX. However, in the LAD, there is evidence of in-stent restenosis located distally within the stent. The 3D volume rendering clearly depicts the stents in both the LAD and LCX. Corresponding invasive coronary angiography confirms the presence of in-stent restenosis in the LAD and the patent stent in the LCX
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Coronary artery assessment
CCTA has emerged as a pivotal first-line diagnostic test for patients suspected of coronary artery disease [11]. However, the accurate quantification of coronary stenosis remains a challenge, particularly in patients with extensive or dense coronary artery calcifications. These calcifications can lead to blooming artefacts, often resulting in overestimated stenosis severity and false-positive diagnoses [18]. A previous meta-analysis demonstrated that CCTA, on a per-patient level, achieved a pooled sensitivity of 99%, specificity of 89%, median positive predictive value of 93% (range 64–100%), and negative predictive value of 100% (range 86–100%) for detecting significant stenosis as defined by invasive coronary angiography (ICA) [19].
The increased spatial resolution, along with the maintained high temporal resolution provided by dual-source PCDs, plays a crucial role in reducing blooming artefacts. This high-resolution capability, even allowing an ultra-high resolution (UHR) mode, is a defining feature of PCD-CT technology, enabling more detailed and precise imaging than is possible with conventional CT systems. Although slice thickness varies between systems and resolution modes, it is thinner (down to 0.2 mm) than that achieved with conventional EID-CT [1, 3, 4, 20]. In the UHR mode, it is recommended to employ dedicated sharp kernels for optimal visualisation of coronary plaques and the vessel lumen [21]. Figure 3b presents an example of UHR imaging.
In an initial study involving 14 patients, the UHR mode of PCD-CT enabled improved image quality and diagnostic confidence for CCTA examinations at a comparable dose, in comparison with conventional EID-CT [7]. Furthermore, a phantom study indicated that UHR CCTA significantly reduces blooming artefacts and improves stenosis quantification compared with standard resolution CCTA, indicating enhanced accuracy [22]. A head-to-head comparison between EID-CT and UHR PCD-CT in patients with dense coronary calcifications was carried out in the study by Koons et al. [23]. This research demonstrated a decrease in percent diameter stenosis by an average of 11% due to the reduction of blooming artefacts with the use of UHR PCD-CT compared with EID-CT. As a result, 13 out of 34 stenoses were downgraded in the stenosis severity category based on the Coronary Artery Disease Reporting and Data System. Specifically, nine were downgraded from mild to minimal, three from moderate to minimal, and one from moderate to mild. In addition, two were upgraded from minimal to mild. It is important to note that this comparison did not include a reference standard such as ICA.
While the UHR mode in PCD-CT enhances spatial resolution, an equally important feature of PCD-CT technology is its inherent spectral imaging capabilities [1]. The study by McCollough et al. compared standard resolution PCD-CT, utilising its spectral capabilities, with EID-CT. Their results showed that PCD-CT at 100 keV effectively reduced calcium blooming compared with EID-CT, resulting in a decrease in the visual estimates of percent diameter luminal stenosis [24]. The spectral capabilities of PCD-CT also offer a calcium-removal reconstruction algorithm, which enables lumen evaluation without the influence of blooming artefacts. The study by Nishihara et al. demonstrated that the calcium-removal image algorithm using PCD-CT improved diagnostic accuracy over conventional images and enhanced image interpretability of severely calcified coronary lesions [25].
A recent study by Hagar et al. focused on evaluating the diagnostic accuracy of UHR PCD-CT in detecting coronary artery disease in patients with severe aortic valve stenosis referred for transcatheter aortic valve replacement (TAVR) [26]. Using ICA as the reference standard, this prospective study involved 68 participants with a median CAC score of 414 (25th–75th percentile: 125–1246). The results demonstrated a sensitivity of 96%, specificity of 84%, positive predictive value of 77%, negative predictive value of 97%, and overall accuracy of 88% in the detection of stenosis of ≥ 50%.
Given the current evidence indicating that PCD-CT can effectively decrease blooming artefacts and enhance stenosis assessment accuracy, this technology has the potential to reduce false-positives in coronary artery disease diagnosis. Building on the already high negative predictive value of CCTA, PCD-CT might also improve specificity, even in patients with severe calcifications. This improvement could lead to a decrease in both unnecessary ICAs and repeated scans, providing a more patient-friendly approach and ultimately offering potential cost benefits while reducing radiation exposure [27].
Functional assessment of coronary stenosis
Functional assessment of coronary stenosis through CT-derived fractional flow reserve (FFRCT) offers another promising approach for reducing unnecessary ICAs. The enhanced visualisation of coronary stenosis and reduction in blooming artefacts observed with PCD-CT may directly impact FFRCT computation. Zsarnoczay et al. demonstrated the feasibility of FFRCT with PCD-CT, reporting excellent correlation and strong agreement with conventional EID-CT [28]. Furthermore, in a study involving TAVR patients, Brendel et al. found that the integration of PCD-CT, combined with artificial intelligence-derived CCTA stenosis quantification and FFRCT, could potentially obviate the need for ICA in 121 out of 260 patients (46.5%) [27]. These findings underscore the potential of FFRCT in combination with PCD-CT to optimise patient management strategies by reducing unnecessary invasive procedures. This is especially relevant in frail patients such as the TAVR population.
Stent imaging
The assessment of in-stent restenosis remains challenging in conventional CT due to blooming and beam-hardening artefacts. However, PCD-CT shows promise in enhancing the sensitivity and specificity of CT for patients with prior stent placement [29, 30]. Key to this improvement is the selection of appropriate acquisition and reconstruction parameters tailored for stent imaging. UHR imaging, particularly when combined with sharp stent-specific kernels at a tube voltage of either 120 or 140 kV, appears to be the most effective approach [31]. At present, the high resolution provides the greatest added value for evaluating the stent lumen. Nevertheless, the integration of spectral imaging with the UHR mode promises to further enhance diagnostic capabilities for stent evaluation.
In a study by Hagar et al., UHR PCD-CT was used to evaluate coronary stent patency in 18 participants with 44 stents, demonstrating high diagnostic accuracy (89%) compared with ICA, which relied on visual assessment [32]. The study reported excellent sensitivity (100%) and specificity (87%), high negative predictive (100%) value and substantial inter-reader agreement, indicating the potential of UHR PCD-CT in stent assessment. While these findings are promising, more evidence is needed before PCD-CT can be considered a definitive alternative to ICA for ruling out in-stent stenosis. Figure 3c displays an example of stent imaging with PCD-CT.
Myocardial fibrosis
Assessment of myocardial fibrosis in current practice
To date, late enhancement (LE) with gadolinium in cardiovascular magnetic resonance (CMR) imaging is considered the reference standard for the non-invasive assessment of myocardial infarction, scar and viability [33]. The application of LE imaging in CMR (LECMR) is not only confined to the evaluation of infarction but is also useful in any type of pathology causing focal myocardial fibrosis [34]. The principle of LE imaging is based on the accumulation and retainment of contrast agents in an enlarged extracellular space [35, 36]. In patients with acute or chronic myocardial injury, this extracellular volume (ECV) is enlarged, either by oedema and cardiomyocyte membrane rupture, or by replacement fibrosis. Focal fibrosis is commonly assessed visually or semi-quantitively, while diffuse fibrosis is measured quantitatively using native T1 and ECV mapping [37]. LECMR and T1/ECV mapping enable differentiation between ischaemic and non-ischaemic diseases such as sarcoidosis, amyloidosis, dilated cardiomyopathy and myocarditis by visualising typical LECMR patterns and native T1 and ECV maps [36, 38]. Furthermore, the presence and extent of fibrosis on LECMR may change therapy and is highly correlated to prognosis [38].
Late enhancement imaging with CT
Technological advances have paved the way for visualising fibrosis with CT in addition to CMR. A study by Andreini et al. revealed a high diagnostic concordance of 94.7% between LECMR and LE with CT (LECT) patterns [39].
The introduction of LECT in clinical settings may be favourable as it encompasses several advantages. By combining CCTA and LECT in a single examination, CT could serve as a one-stop-shop assessing both coronary artery disease and myocardial enhancement patterns. This allows not only differentiation between ischaemic and non-ischaemic cardiomyopathy, but also the assessment of viability in the case of ischaemic cardiomyopathy using a single modality. In addition, important contraindications for CMR, such as claustrophobia, non-MRI-conditional cardiac devices or ferromagnetic implantations, do not apply to CT. In general, CT scanning is readily available with shorter scanning times, while CMR may suffer from longer waiting lists, longer acquisition times and higher costs. Nevertheless, incorporating LECT into its scan protocol does lengthen CT acquisition time as well, which is also accompanied with an increased radiation and at times a higher contrast dose. An example of a combined CCTA and LE(PCD-)CT scan protocol is described in Fig. 4.
Fig. 4
Photon-counting detector CT imaging protocol as a one-stop-shop for both coronary artery assessment and late enhancement imaging. The duration of a regular coronary CT angiography (CCTA) protocol is approximately 10 min, an additional late enhancement (LE) CT acquisition extends the total duration to approximately 15–20 min. Acquisition times may differ between centres. A haematocrit assessment is only necessary for the optional extracellular volume (ECV) assessment acquired 5–10 min after contrast administration. A native scan is optional as it can be reconstructed as a virtual non-iodine image
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Multiple studies have proposed LECT imaging in 3rd generation dual-energy CT scanners as an adequate alternative, benefiting from higher spatial resolution when compared with CMR and surpassing the discriminatory capacities of single-energy CT scanners [40]. However, CMR remains the reference standard as the implementation of LECT is mostly constrained by a relatively low contrast-to-noise ratio [41]. PCD-CT might improve this issue, benefiting from a substantially higher spatial resolution and improved contrast-to-noise ratio [42]. An initial case study with LEPCD-CT has shown hyper-enhancement patterns remarkably similar to the pattern visualised with LECMR [43].
Multi-energy acquisition could augment the versatility of PCD-CT to an even greater extent, as this approach facilitates the separation of multiple contrast agents when administered simultaneously [1, 44]. Symons et al. have demonstrated the feasibility of this concept in an occlusion-reperfusion canine model of myocardial infarction [45]. By combining iodine, gadolinium and soft tissue maps in PCD-CT, infarcted myocardium could be adequately distinguished from blood pool and normal myocardial tissue, in comparison with CMR and histopathology [45]. This could in theory facilitate the simultaneous assessment of coronary arteries (using iodine) and fibrosis (using gadolinium) within the same scan.
Extracellular volume measurements with CT
Derived from CMR native and post-contrast T1 mapping, quantitative analysis with ECVCMR calculations reflects the extent of the extracellular space [33]. This technique provides essential additional information, not only due to its ability to quantify the magnitude of fibrosis but also in the detection of diffuse fibrosis and early subtle fibrotic changes not readily visible with LECMR imaging [41].
ECV imaging with cardiac CT (ECVCT) has been compared with ECVCMR in assessing diffuse myocardial fibrosis by several studies, hereby providing an appealing alternative to CMR [41]. A recent meta-analysis of 17 studies showed good agreement and excellent correlation of ECVCT when compared with ECVCMR [46]. ECVCT can be calculated using the same principle as ECVCMR, but instead of differences in T1 signal, it relies on differences in attenuation, measured in Hounsfield units [41]. With dual-energy CT, the iodine-density derived method for ECVCT calculation uses generated iodine-specific images and does not require non-contrast data [40].
ECVCMR measurements previously demonstrated their clinical significance in terms of prognostic correlations [47]. Similar trends have been reported in ECVCT measurements. Elevated ECVCT has been associated with an increased risk of heart failure hospitalisation, major adverse cardiac events, and/or all-cause mortality in post-intervention cases and multiple cardiovascular diseases [48‐50].
A recent study by Mergen et al. confirmed the feasibility of ECV measurements in PCD-CT (ECVPCD-CT) from the iodine ratio of LE scans in 30 patients with severe aortic stenosis undergoing PCD-CT for pre-procedural planning [51]. However, measurements were not compared with ECVCMR measurements. In contrast, Aquino et al. did match PCD-CT findings with CMR in 29 patients undergoing CMR for several cardiovascular indications, showing strong correlations (r = 0.82–0.91, p < 0.001) and excellent reliability (intraclass correlation coefficient 0.81–0.90) between ECVPCD-CT and ECVCMR [52]. These findings suggest that ECVPCD-CT could serve as an adequate alternative for ECVCMR measurements in cardiovascular imaging. Figure 5 presents an example of LEPCD-CT and ECVPCD-CT in comparison with LECMR images.
Fig. 5
Short-axis photon-counting detector CT (PCD-CT, a and b) and cardiovascular magnetic resonance images (c and d) of a 59-year-old female recently diagnosed with myocardial infarction. Image a shows a PCD-CT extracellular volume (ECV) map of the left ventricle with focal increased ECV in the basal inferolateral segment. Image b shows a calculated iodine map with retainment of iodine in an ischaemic pattern, corresponding with an area of late gadolinium enhancement on cardiovascular magnetic resonance (Imagec). Image d shows a short-axis cine image (after gadolinium administration) in which increased signal intensity and regional wall motion abnormalities were observed in the basal inferolateral segment, indicative of myocardial infarction
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Future directions and challenges
PCD-CT has emerged as a novel imaging technique with promising results, especially in cardiac imaging. Alongside the previously stated applications, several other possibilities may be considered.
One of these possibilities is improved quantitative plaque characterisation with PCD-CT. The UHR mode of PCD-CT has demonstrated lower total plaque volumes and calcified plaque components compared with reference standard reconstructions [53]. Adding spectral information could improve plaque quantification with VMI reconstructions. Nevertheless, standard protocols are needed to determine which VMIs are optimal for plaque volume assessment [54]. Through the integration of both high resolution and spectral information, PCD-CT facilitates the characterisation of plaque features, including lipid-rich necrotic cores, spotty calcifications and plaque ulceration. This detailed characterisation offers valuable insights into plaque vulnerability and the risk of rupture, crucial considerations in determining patient prognosis and enhancing treatment strategies, even in asymptomatic patients.
PCD-CT might come to play a role in epicardial adipose tissue (EAT) imaging. The density and extent of pericoronary EAT serve as a marker for vascular inflammation, which seems to have predictive value for adverse cardiac events [55]. Mergen et al. conducted a study assessing pericoronary EAT attenuation measurements with PCD-CT at different VMI energy levels in a phantom model [56]. VMI reconstructions at 70 keV offered the most precise estimates of fat attenuation when compared with conventional CT at 120 kV [56]. In a study by Risch et al., virtual non-contrast reconstructions derived from PCD-CT angiography datasets did provide consistent EAT volume measurements in comparison with true non-contrast series, allowing reduction in radiation dose and acquisition time [57]. These findings may aid in the standardisation of pericoronary EAT assessment.
Multiple studies have investigated the viability of myocardial perfusion CT, suggesting similar accuracy when compared with CMR perfusion imaging [58]. However, the assessment of iodine maps can be hindered due to beam hardening and other artefacts [58]. PCD-CT could prove advantageous by reducing these artefacts alongside its increased spatial and temporal resolution. Combining CT perfusion with CCTA and LE imaging in patients with intermediate stenoses, where haemodynamic significance is not certain, facilitates the evaluation of myocardial ischaemia, coronary anatomy and myocardial tissue viability in a single PCD-CT examination. This provides a one-stop-shop for making clinical decisions regarding revascularisation. In a case report, Polacin et al. detected hypodense myocardium with non-contrast PCD-CT and reduced iodine concentrations in the same region on dual-energy iodine maps from PCD-CT angiography images, corresponding with an ischaemic transmural scar visualised on LECMR [59].
In both pre-procedural and post-procedural imaging of valvular interventions, the use of PCD-CT could also become of interest. In pre-procedural planning, higher spatial resolutions and blooming artefact reduction allow reliable depiction of important anatomic structures. Specifically in the context of patients undergoing TAVR, integrating LEPCD-CT into their pre-procedural scan protocol can even offer prognostic insights. Alongside their previously mentioned prognostic implications, pre-operative ECV measurements in TAVR patients can predict prognosis [60]. Furthermore, LEPCD-CT can assist in the detection of concomitant cardiac amyloidosis in this population. Its identification carries prognostic implications and can impact treatment strategies [61]. On the other hand, in post-procedural imaging of valvular interventions, other advantages of PCD-CT are of value, such as metal artefact reduction and spectral reconstructions. These aspects can aid in the diagnostic dilemma regarding the increasing gradient in prosthetic valves by allowing more accurate assessment of the implanted valve and differentiation between post-procedural complications such as thrombus and pannus formation, bioprosthetic degenerative disease and endocarditis [62].
Another anticipated prospect arising from the application of PCD-CT technology is the potential for both contrast and radiation dose reduction. Research by Yu et al. revealed that the contrast-to-noise ratio of iodine contrast versus water increased by as much as 25% with PCD-CT when compared with conventional CT [63]. This implicates that reduced iodine concentrations in contrast media may suffice for adequate lumen visualisation. Furthermore, the enhanced contrast-to-noise ratio associated with PCD-CT can lead to a decrease in radiation dose. Several studies have examined this hypothesis and indicated reductions in radiation levels ranging from 30–60% [1]. The previously stated possible outcomes of PCD-CT do not solely improve image quality but could also aid in mitigating the risks associated with contrast and radiation exposure during clinical imaging procedures.
All the previously discussed possibilities and benefits for PCD-CT position it as a strong candidate for becoming the new standard; however, certain limitations associated with the use of PCD-CT in cardiac imaging are worth mentioning. Firstly, while registries can provide insights into the diagnostic performance of PCD-CT, large-scale clinical trials are necessary to establish its clinical utility and impact. These studies are crucial for investigating whether advanced technologies such as PCD-CT can reduce downstream testing, improve cost-effectiveness, and enhance patient outcomes through better risk stratification and personalised treatment approaches. Secondly, standardisation of imaging protocols and post-processing techniques among centres are essential to reproduce and compare findings. In addition, the availability of PCD-CT scanners is rather limited and costly as the production is still in the relatively early stages. When PCD technology becomes more established, production costs will likely decrease. Addressing cost-effectiveness is important for the implementation of PCD-CT in routine clinical practice.
Lastly, the expanding possibilities offered by PCD-CT highlight the need for increased collaboration between cardiovascular radiologists and imaging cardiologists. This collaboration is essential for identifying relevant indications, correct clinical interpretation of PCD-CT images and defining appropriate PCD-CT scan protocols.
Conclusion
In conclusion, PCD-CT currently enhances diagnostic accuracy with its high spatial resolution, reduced calcium blooming, minimised artefacts, precise stenosis grading and stent imaging capabilities. These advancements lead to better risk stratification of patients. Looking ahead, tissue characterisation, especially through the integration of UHR imaging with spectral information, and both pre-procedural and post-procedural imaging, will become increasingly important. Furthermore, PCD-CT holds potential for reducing radiation doses and contrast media volume without compromising image quality, enhancing patient safety. This technology could reduce the necessity for invasive procedures and further testing, thereby improving patient outcomes and optimising healthcare resource utilisation.
Funding
This work was supported by an Academic Grant (Maastricht UMC +2023 to Dr. M.W. Smulders and Dr. C. Mihl).
Conflict of interest
M.W. Smulders: Speakers fee ESC highlights ’22 and ’23—Daiichi Sankyo Europe. Academic Grant by Maastricht UMC+. R.P.J. Budde: Institutional support to EMC by Siemens and Heartflow. Speakers fee Bayer. A. Hirsch: Editor for Netherlands Heart Journal. Received a research grant and consultancy fees from GE Healthcare and speaker fees from GE Healthcare and Bayer. He is also a member of the medical advisory board of Medis Medical Imaging Systems and was MRI corelab supervisor of Cardialysis BV until 2022. C. Mihl: Speakers bureau Bayer Healthcare. Academic Grant by Maastricht UMC+. MJ.D.K. Lemmens and S.P. Sharma declare that they have no competing interests.
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