What’s New in Photon Counting CT?

July 05, 2026 · 23 articles · 15 research themes · covering June 28, 2026 – July 05, 2026

Overview

Across this week’s set of papers, photon-counting CT (PCD/PCCT) is repeatedly positioned as a platform for turning raw x-ray data into more actionable information—especially via spectral reconstructions (e.g., virtual monoenergetic imaging, iodine quantification, and material decomposition) and quantitative biomarkers. Several studies focus on how to operationalize these capabilities: task-optimized abdominal reconstructions to improve diagnostic performance and dose efficiency; quantitative iodine density to distinguish neoplastic from bland portal vein thrombosis in hepatocellular carcinoma; and spectral parameters derived from arterial/venous lesion imaging to predict PD-L1 expression in NSCLC. Together, these works emphasize a shift from “morphology-only” CT toward quantitative, biology-relevant imaging.

A second dominant theme is making PCD/PCCT practical and reliable in real-world clinical workflows. Multiple papers address reproducibility and standardization problems that arise when moving from conventional CT to photon-counting systems: optimizing coronary artery calcium (CAC) scoring protocols to reduce variability (phantom-based thresholding and acquisition-parameter studies), and standardizing coronary contrast delivery using a personalized iodine delivery rate protocol. In parallel, artifact mitigation and image quality enhancement are highlighted—iterative metal artifact reduction presets for knee hardware, deep learning denoising for head-and-neck UHR PCD-CTA, and improved confidence for complex neurovascular diagnoses (e.g., cerebrospinal fluid–venous fistulas in spontaneous intracranial hypotension, and post-interventional assessment of intra-aneurysmal flow disrupting devices). Finally, dose optimization remains central, with Monte Carlo–based organ dose estimation for extremity PCD-CT and head-dose/SNR relationships across image quality levels.

Overall, the digest shows PCD/PCCT maturing along three axes: (1) spectral/quantitative biomarkers that may reduce reliance on invasive sampling (PD-L1, neoplastic PVT), (2) workflow engineering to improve consistency (contrast protocols, CAC reproducibility, follow-up recommendation impact), and (3) robustness improvements (artifact handling, denoising, and confidence gains in challenging neurovascular and peripheral vascular settings).

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Photon-Counting CT (PCD/PCCT) Cardiovascular Imaging

Comparative review of coronary CT angiography versus conventional catheter angiography: diagnostic value, clinical outcomes, and underlying technical principles.

This comparative review studied the diagnostic value and clinical outcomes of coronary CT angiography (CCTA) versus invasive coronary angiography (ICA), synthesizing evidence from 2015 to March 2026 and discussing underlying technical principles including emerging photon-counting detector CT (PCD-CT). It found that CCTA increasingly supports noninvasive risk stratification while ICA remains important for specific clinical scenarios, with performance influenced by modality physics and technical constraints. The review’s significance is to clarify when CCTA (potentially enhanced by PCD-CT) can replace or complement ICA in modern coronary artery disease pathways.

Masri S, Sezdi M · Expert review of medical devices · (2026) · View on PubMed ↗

Orbital Imaging Modalities and Recent Updates.

This review article surveyed orbital imaging modalities and recent updates, highlighting that cone-beam CT and photon-counting CT may add value to orbital imaging alongside established MRI, CT, ultrasound, and PET. It emphasizes modality complementarity—CT for bone assessment, MRI for soft-tissue characterization, and emerging photon-counting CT for potential improvements in spectral/contrast capabilities. The significance is to inform clinicians about where photon-counting CT could fit into an evidence-based orbital imaging workflow.

Martin S · Radiologic clinics of North America · (2026) · View on PubMed ↗

Photon-counting detector CT in cardiovascular imaging: technical advances, clinical applications, and future perspectives.

This narrative review synthesized technical advances, clinical applications, limitations, and future directions of photon-counting detector CT (PCD-CT) for cardiovascular imaging, drawing on studies published from January 2015 to March 2025. The review’s central finding is that PCD-CT’s spectral capabilities (including spectral/spectral CT approaches) and improved photon detection enable enhanced characterization of cardiovascular disease and congenital heart disease, while current constraints include workflow, availability, and remaining technical limitations. Scientifically, it provides an evidence-based roadmap for researchers and clinical imagers to target where PCD-CT can most improve cardiovascular diagnostics and what barriers must be addressed next.

Hong Z, Yao B, Wu H · The international journal of cardiovascular imaging · (2026) · View on PubMed ↗

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Coronary CT Angiography: Contrast Protocols & Quantification

A personalized iodine delivery rate-based injection protocol in coronary angiography on photon-counting CT.

This study proposed and validated a personalized iodine delivery rate (IDR)-based injection protocol for coronary CT angiography (cCTA) on photon-counting CT (PCCT), using an HU target of 500 in 55-keV reconstructions. Using linear regression to derive an IDR formula and validating it in two injection-rate groups (3.5 and 5.0 mL/s), the protocol aimed to achieve equivalent coronary enhancement within a predefined HU range (500±50) and was supported by a reader study of perceived enhancement. A validated IDR protocol could standardize contrast delivery on PCCT, improving quantitative coronary enhancement and potentially reducing contrast-related variability and patient risk.

Busselot T, Giordano P, Sneyers V et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Coronary Artery Calcium (CAC) Scoring & Reproducibility

Coronary artery calcium scoring: expanding the new standard by photon-counting detector CT Part II: Impact of virtual monoenergetic image reconstructions with adjusted calcium scoring thresholds.

This phantom-based study expanded a photon-counting detector CT (PCD-CT) coronary artery calcium (CAC) scoring protocol by testing whether virtual monoenergetic image (VMI) reconstructions with adjusted CAC thresholds reduce score variability. Using a chest phantom with nine calcifications scanned with an optimized PCD-CT protocol (120 kVp, 75% dose, thin slices, quantum iterative reconstruction), images were reconstructed across VMI levels (50–80 keV in 5-keV steps) with threshold adjustments to maintain density. If VMI-based thresholding further improves reproducibility, it could strengthen CAC scoring standardization for cardiovascular risk assessment on PCD-CT.

Fink N, Koetzier LR, Zsarnoczay E et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

Coronary artery calcium scoring: expanding the new standard by photon-counting detector CT-Part I: Impact of tube voltage, tube current, slice thickness, and quantum iterative reconstructions.

This phantom study investigated how photon-counting detector CT (PCD-CT) acquisition parameters affect coronary artery calcium (CAC) scoring variability and aimed to propose a protocol with decreased variability. A chest phantom containing nine calcifications was scanned on PCD-CT across tube voltages (90 vs 120 kVp), tube currents (100% to 25% dose), slice thicknesses (3 mm vs 1 mm), and quantum iterative reconstruction levels (IR 1–4), with interscan variability quantified across settings. Establishing parameter-dependent variability and an optimized protocol could improve reproducibility of CAC scoring when transitioning from energy-integrating CT to PCD-CT.

Fink N, Koetzier LR, Zsarnoczay E et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Peripheral Vascular Imaging (PAD/Extremities)

Spectral Ultrahigh-resolution Photon-counting CT Angiography for Below-knee Peripheral Artery Disease: Impact of Extremity-specific Isotropic Reconstructions.

This post hoc analysis of a prospective cohort evaluated spectral ultrahigh-resolution photon-counting CT angiography for below-knee peripheral artery disease (PAD), focusing on how extremity-specific isotropic voxel spacing affects image quality and diagnostic performance. Consecutive PAD patients underwent lower-limb CTA on a dual-source PCD-CT system in spectral-UHR mode (120×0.2 mm collimation) with reconstructions including down-sampled images to test different isotropic voxel spacings. Identifying the optimal isotropic reconstruction conditions could improve noninvasive vascular assessment in PAD by maximizing the diagnostic value of spectral UHR PCD-CT.

Griggers JI, Todoran TM, Vecsey-Nagy M et al. · Investigative radiology · (2026) · 3 citations · View on PubMed ↗

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Neurovascular Imaging & Intracranial Applications

Improved Diagnostic Certainty of Photon-Counting CT Myelography Compared with Energy-Integrating CT for CSF-Venous Fistulas in Spontaneous Intracranial Hypotension.

This retrospective study compared photon-counting detector CT myelography (PCD-CTM) with energy-integrating detector CT myelography (EID-CTM) for detecting cerebrospinal fluid–venous fistulas (CVFs) in 456 patients (628 CTM examinations) with spontaneous intracranial hypotension. Using the Duke CSF-Venous Fistula Confidence Score (DCCS) assigned by two neuroradiologists, PCD-CTM improved CVF detection certainty versus EID-CTM. The result supports PCD-CTM as a higher-confidence imaging option for diagnosing CVFs in SIH, potentially improving downstream management.

Christensen SK, Kranz PG, Madhavan AA et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗ · Free PDF ↗

Photon-counting CT-angiography in comparison to digital subtraction angiography and MR-angiography for assessing intra-aneurysmal flow disrupting devices.

This retrospective study evaluated photon-counting detector CT angiography (PCD-CTA) for post-interventional assessment of intra-aneurysmal flow disrupting devices (IAFD) in consecutive patients with intracranial aneurysms treated between April 2023 and April 2025, comparing PCD-CTA with MR angiography and digital subtraction angiography (DSA). PCD-CTA used polyenergetic imaging plus iodine and virtual monoenergetic reconstructions at 40 and 80 keV with different head vessel kernels (Hv56, Hv72), with and without iterative metal artifact reduction, to characterize intra-aneurysmal flow disruption relative to reference vascular imaging. If validated in the full results, PCD-CTA could provide a less invasive, artifact-managed alternative to DSA/MRA for routine follow-up of IAFD-treated aneurysms.

De Beukelaer F, Wuyts LL, Wiesmann M et al. · Acta neurologica Belgica · (2026) · View on PubMed ↗ · Free PDF ↗

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Head & Neck UHR PCD-CT: Image Quality & Denoising

Impact of Deep Learning-Based Denoising on Image Quality and Diagnostic Confidence in Neurovascular Ultrahigh-Resolution Photon-Counting CT Angiography.

This retrospective single-center study evaluated whether deep learning-based denoising improves image quality and diagnostic confidence in 42 patients undergoing head and neck ultrahigh-resolution photon-counting CT angiography (UHR PCD-CTA). Images reconstructed with vendor iterative reconstruction (level 4) were compared with and without an additional post hoc AI denoising algorithm, focusing on noise reduction and reader confidence in neurovascular assessment. The clinical significance is that AI denoising may make UHR PCD-CTA more reliable in low-signal and artifact-prone regions such as the lower neck.

Tóth A, Hagar MT, Silbergleit M et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Audiology–Imaging Integration (Conductive Hearing Loss)

Conductive hearing loss and normal CT: a clinical perspective.

This clinical perspective reviewed literature and provided illustrative cases linking audiology with photon-counting detector CT findings in patients with conductive hearing loss who had normal or non-explanatory temporal bone CT. The key message was that while conductive hearing loss is often attributable to CT-detectable pathology (e.g., otosclerosis), imaging can be falsely negative and some pathophysiologic conditions may not be visualized on CT. Clinically, this supports integrating audiologic testing with imaging and avoiding over-reliance on a “normal CT” when evaluating conductive hearing loss.

Rao D, Raymond MJ, Breen JT et al. · Neuroradiology · (2026) · View on PubMed ↗

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Oncology Imaging with PCD-CT (Lung/Breast/Thoracic)

Lesion conspicuity assessment of prone 40-keV virtual monoenergetic imaging in arterial-phase photon-counting CT for breast cancer: a retrospective comparison with DCE-MRI.

This retrospective diagnostic feasibility study evaluated prone 40-keV virtual monoenergetic imaging (VMI) from arterial-phase photon-counting detector CT (PCD-CT) in 22 women with surgically confirmed primary breast cancer, comparing lesion conspicuity against dynamic contrast-enhanced T1-weighted MRI (DCE-T1WI). Lesion conspicuity from 40-keV PCD-CT VMI was assessed by three independent readers and compared with DCE-T1WI across reconstructed 40- and 70-keV images from a single arterial-phase acquisition. If 40-keV PCD-CT achieves comparable conspicuity to DCE-MRI, it could support prone whole-body PCD-CT staging workflows for breast cancer by reducing reliance on MRI for lesion detection.

Kawasaki Y, Nakajima M, Yokoyama K et al. · Japanese journal of radiology · (2026) · 1 citations · View on PubMed ↗ · Free PDF ↗

Photon-counting detector computed tomography in thoracic oncology: revolutionizing tumor imaging through precision and detail.

This narrative review summarized technical advances and clinical applications of photon-counting detector CT (PCD-CT) in thoracic oncology, emphasizing spatial resolution, dose–image-quality tradeoffs, and intrinsic spectral imaging. It synthesized evidence from PubMed searches through May 31, 2025, focusing on how PCD-CT may improve tumor imaging and practical implementation in thoracic cancer care. By consolidating current capabilities and limitations, the review supports translation of PCD-CT into thoracic oncology workflows for more precise and detailed imaging.

Yanagawa M, Ueno M, Ito R et al. · Diagnostic and interventional radiology (Ankara, Turkey) · (2026) · 1 citations · View on PubMed ↗ · Free PDF ↗

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Spectral Biomarkers for Immunotherapy (PD-L1)

Quantitative spectral parameters of photon-counting detector CT for noninvasive prediction of PD-L1 expression in non-small cell lung cancer.

This single-center retrospective study assessed whether quantitative photon-counting CT (PCCT) spectral parameters can noninvasively predict programmed death-ligand 1 (PD-L1) expression in 63 patients with non-small cell lung cancer (NSCLC). Using immunohistochemistry-defined PD-L1 groups (TPS <1%, 1–49%, and ≥50%) as the reference, the authors measured arterial/venous lesion CT values at 40, 70, and 100 keV and iodine concentration to derive predictive spectral features. If validated, these PCCT spectral biomarkers could help select NSCLC patients for immunotherapy by estimating PD-L1 status without tissue sampling.

Ren J, Fu Z, Li L et al. · BMC medical imaging · (2026) · View on PubMed ↗ · Free PDF ↗

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Venous Thromboembolism Characterization (Portal Vein Thrombosis)

Photon-counting detector CT with iodine quantification: improved distinction between bland and neoplastic portal vein thrombosis.

This retrospective single-center study evaluated whether photon-counting detector CT (PCD-CT) iodine density (ID) quantification can distinguish neoplastic from bland portal vein thrombosis (PVT) in 104 patients with suspected PVT and underlying hepatocellular carcinoma. By using quantitative iodine density measurements from contrast-enhanced PCD-CT, the study assessed diagnostic performance of ID for differentiating neoplastic versus bland PVT based on follow-up and multidisciplinary consensus. Improved discrimination of neoplastic PVT could refine prognostication and treatment selection in HCC by replacing subjective imaging criteria with quantitative spectral metrics.

Müller L, Jorg T, Grunz JP et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Abdominal Imaging Workflow & Task-Optimized Spectral Reconstructions

Seeing the invisible: practical strategies to maximize the clinical impact of photon-counting CT in abdominal imaging.

This article reviewed practical strategies to maximize the clinical impact of photon-counting CT (PCD-CT) in abdominal imaging, focusing on how its direct photon-to-signal conversion enables spectral and quantitative reconstructions. It highlights that retrospective reconstruction—such as virtual monoenergetic imaging and material decomposition—can be tailored to specific abdominal tasks to improve diagnostic performance and dose efficiency. The review positions PCD-CT as a shift from morphology-only assessment toward task-optimized spectral imaging in routine abdominal care.

Yokoyama K, Kawasaki Y, Fujii M et al. · Abdominal radiology (New York) · (2026) · View on PubMed ↗ · Free PDF ↗

Follow-up recommendation rates with abdominopelvic photon counting CT: comparison with conventional dual-energy and single-energy CT.

This retrospective PACS-based study compared follow-up imaging recommendation rates after abdominopelvic photon-counting CT (PCCT) versus conventional dual-energy CT (DECT) and single-energy CT (SECT). Examinations lacking virtual noncontrast and iodine map images were excluded, and radiology reports were reviewed for whether follow-up imaging was recommended and the stated reasons, with rates compared across scanner groups. If PCCT reduces unnecessary follow-up recommendations, it could lower downstream costs and patient burden while maintaining diagnostic adequacy.

Dane B, Attlassy Y, Ihionkhan E et al. · Abdominal radiology (New York) · (2026) · 1 citations · View on PubMed ↗

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Radiation Dose Optimization & Dosimetry (including Extremity/Head)

Organ dose optimization for a point-of-care forearm X-ray photon-counting CT.

The study evaluated spectral shaping for point-of-care forearm extremity photon-counting detector CT (PCD-CT) by estimating organ absorbed dose using Monte Carlo simulations across different source voltages and filtration settings. Spectral shaping combinations reduced organ absorbed dose compared with conventional CTDI-based optimization while maintaining image-quality constraints (as assessed in the simulation framework). This patient-relevant dosimetry approach supports more accurate, organ-specific radiation risk reduction strategies for photon-counting extremity CT.

Rodesch PA, Viry A, Khorsi M et al. · Computers in biology and medicine · (2026) · View on PubMed ↗ · Free PDF ↗

Investigating Radiation Dose and Signal-To-Noise-Ratio in Pediatric and Adult Head Photon-Counting CT: A Phantom-Based Study.

This phantom-based study investigated the relationship between radiation dose and signal-to-noise ratio (SNR) in pediatric and adult head photon-counting CT (PCCT) across different image quality levels (IQLs). Anthropomorphic phantoms were scanned over multiple IQLs, and dose metrics (mAs, CTDIvol, DLP, organ doses) were correlated with SNR in brain parenchyma and bone, with comparisons performed at matched IQLs. Defining how SNR changes nonlinearly with dose across age groups could enable more efficient PCCT dose optimization while preserving diagnostic image quality.

Klüner LV, Opitz MK, Peuster H et al. · RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin · (2026) · 1 citations · View on PubMed ↗ · Free PDF ↗

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Artifact Reduction & Metal Management in PCD-CT

Comparison of Iterative Metal Artifact Reduction Presets In Ultra-high-resolution Photon-counting CT Angiography of Patients with Total Knee Endoprosthesis.

This study investigated how different iterative metal artifact reduction (IMAR) presets affect image quality and diagnostic performance in ultra-high-resolution photon-counting CT angiography (UHR-PCCTA) for patients with total knee endoprostheses. In 25 patients (31 lower extremities) undergoing UHR-PCCTA, varying IMAR settings were compared to determine which preset best mitigated metal artifacts that obscure the popliteal vasculature. The findings are clinically significant for improving noninvasive peripheral artery assessment in patients with knee joint replacement hardware.

Huflage H, Kunz AS, Wech T et al. · Academic radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Musculoskeletal Imaging & Osteoarthritis (CT-based methods/crystal detection)

The current state of computed tomography in osteoarthritis research.

This review summarized the current state of computed tomography (CT) methods used in osteoarthritis (OA) research, covering structural features, 3D shape modeling, alignment, contact stress modeling, bone morphometry and bone mineral density, cartilage, meniscus, and multimodal combinations. It emphasizes CT’s high-resolution bone visualization for quantifying osteophytes, subchondral bone cysts, sclerosis, and joint space width, and for enabling accurate 3D bone shape modeling and mechanics-related analyses. The significance is to guide researchers in selecting CT-based techniques that best capture OA structural and biomechanical phenotypes.

Yoshikawa R, Boddu A, Turmezei TD et al. · JBMR plus · (2026) · View on PubMed ↗ · Free PDF ↗

Pediatric pseudo-tumor of the ischio-pubic ramus in virtual non-calcium photon-counting scanner: A case report.

This case report described an 11-year-old elite athlete with ischio-pubic ramus synchondrosis that was initially misinterpreted as a tumor on MRI, and it was subsequently clarified using virtual non-calcium imaging on a photon-counting CT scanner. The key finding was that virtual non-calcium (low-dose) photon-counting CT provided straightforward interpretation that corrected the suspected tumor diagnosis. Clinically, it suggests that virtual non-calcium photon-counting CT can reduce diagnostic uncertainty for pediatric pelvic pseudo-tumors that mimic malignancy on conventional imaging.

Corelli C, Balligand T, Rodriguez R et al. · Radiology case reports · (2026) · View on PubMed ↗ · Free PDF ↗

Accuracy of dual-energy computed tomography (CT), ultrasound, cone-beam CT, and spectral photon-counting CT for detecting calcium crystal deposition in the osteoarthritic hand: a cross-sectional diagnostic test study.

This prospective cross-sectional diagnostic test study assessed dual-energy CT (DECT), ultrasound (US), cone-beam CT (CBCT), and multi-energy spectral photon-counting CT (SPCCT) for detecting calcium pyrophosphate (CPP) and hydroxyapatite crystal deposition in patients scheduled for finger-joint surgery due to osteoarthritis. The reference standard was compensated polarized light microscopy of synovial fluid and histology, with SPCCT performed ex vivo on excised joint material. Demonstrating superior or complementary accuracy of SPCCT could improve noninvasive identification of crystal types underlying hand osteoarthritis and guide more targeted clinical management.

Døssing A, Stamp LK, Becce F et al. · Scandinavian journal of rheumatology · (2026) · View on PubMed ↗ · Free PDF ↗

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Generated automatically on July 05, 2026. Covers PubMed articles published June 28, 2026 – July 05, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.