What’s New in Photon Counting CT?

July 04, 2026 · 23 articles · 15 research themes · covering June 27, 2026 – July 04, 2026

Overview

Across this week’s set of studies and reviews, photon-counting CT (PCD/PCCT) is consistently framed as a technology shift driven by spectral information (iodine/material discrimination, virtual monoenergetic reconstructions) plus improved spatial resolution—enabling more quantitative imaging in areas where conventional CT can be limited by noise, artifacts, or non-specific contrast.

The dominant clinical momentum is in vascular and oncology applications. Multiple works target noninvasive alternatives to invasive or less specific pathways: PCD-CTA for follow-up of intracranial flow-disrupting devices, PCD-CT myelography for cerebrospinal fluid–venous fistulas in spontaneous intracranial hypotension, and spectral-UHR PCD-CTA for peripheral artery disease. In parallel, oncology studies leverage iodine/spectral parameters as biomarkers—predicting PD-L1 expression in NSCLC and assessing breast lesion conspicuity in a prone arterial-phase workflow—while a thoracic oncology narrative review emphasizes how spectral imaging may improve tumor characterization and response assessment.

A second major theme is protocol engineering to make photon-counting CT practical and reproducible: dose optimization (including dose–SNR relationships and Monte Carlo absorbed-dose modeling), reconstruction and denoising strategies (AI denoising, kernel/monoenergetic choices, metal artifact reduction), and contrast delivery standardization (personalized iodine delivery rate protocols and iodine density quantification for portal vein thrombosis subtyping). Finally, several phantom- and PACS-based studies highlight the push toward consistency—especially for coronary artery calcium scoring variability—and toward measurable downstream impact on reporting and follow-up recommendations.

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Neurovascular imaging & follow-up (aneurysm devices, myelography, SIH/CVF)

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

This retrospective comparative study evaluated photon-counting detector CT myelography (PCD-CTM) versus energy-integrating detector CT myelography (EID-CTM) for detecting cerebrospinal fluid–venous fistulas (CVFs) in spontaneous intracranial hypotension (SIH) using the Duke CSF-Venous Fistula Confidence Score (DCCS). Across 628 CTM examinations in 456 SIH patients (2020–2025), PCD-CTM improved CVF detection certainty compared with EID-CTM based on DCCS scoring by two neuroradiologists with consensus adjudication. Scientifically and clinically, this supports photon-counting CT myelography as a higher-confidence imaging option for identifying CVFs that guide SIH 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 (IAFDs) in consecutive patients with intracranial aneurysms treated between April 2023 and April 2025. PCD-CTA with iodine and virtual monoenergetic reconstructions (40 and 80 keV), different head vessel kernels (Hv56/Hv72), and iterative metal artifact reduction was compared against MR angiography and digital subtraction angiography (DSA) for evaluating intra-aneurysmal flow disruption. The findings support PCD-CTA as a potentially effective, less invasive imaging alternative to DSA/MRA for follow-up of IAFDs, with optimization of keV/kernel and metal artifact reduction likely improving device visualization and assessment.

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

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Oncology imaging & biomarkers (lung, breast, thoracic oncology, immunotherapy)

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 pretherapeutic immunohistochemistry PD-L1 TPS categories (negative <1%, intermediate 1–49%, high ≥50%) and lesion measurements of arterial/venous CT values at 40, 70, and 100 keV plus iodine concentration, the study identified spectral/iodine-derived parameters associated with PD-L1 expression levels. Clinically, this supports a noninvasive imaging biomarker approach to stratify NSCLC patients for immunotherapy-related decision-making.

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

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) derived 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 on 40-keV PCD-CT VMI was assessed by three independent readers and compared with DCE-T1WI, with the study designed to determine whether PCD-CT staging in the prone position can achieve comparable conspicuity. If validated, prone arterial-phase PCD-CT could provide a single-session, quantitative spectral CT alternative to DCE-MRI for preoperative breast cancer staging and 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 advances and clinical applications of photon-counting detector CT (PCD-CT) in thoracic oncology, focusing on how intrinsic spectral imaging and improved spatial resolution/dose-image-quality tradeoffs may enhance tumor imaging. The authors synthesized evidence from PubMed through May 31, 2025, using search terms related to photon counting CT and thoracic oncology, and discussed practical implications for clinical implementation. By consolidating current technical and translational progress, the review highlights how PCD-CT could enable more precise characterization of thoracic tumors and potentially improve staging, response assessment, and treatment planning.

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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Cardiac CT angiography & coronary imaging (CCTA, ICA comparison, injection protocols)

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 photon-counting detector CT (PCD-CT). It concluded that CCTA is increasingly central for noninvasive coronary artery disease risk stratification, while ICA remains important for specific clinical scenarios and is constrained by invasiveness and procedural limitations. The significance is that it clarifies how evolving CT technologies (including PCD-CT) may shift the balance between noninvasive and invasive coronary imaging.

Masri S, Sezdi M · Expert review of medical devices · (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) specifically for cardiovascular imaging, drawing on studies published from January 2015 to March 2025. The review highlights that PCD-CT enables spectral/spectral CT capabilities and improved material discrimination relevant to coronary artery disease and congenital heart disease, while also outlining ongoing constraints such as technical complexity, availability, and performance tradeoffs. Scientifically and clinically, it provides an evidence-based framework to guide researchers and imagers in selecting PCD-CT protocols and targeting future developments for cardiovascular diagnostics.

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

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Coronary artery calcium (CAC) scoring & reproducibility (phantoms/protocol optimization)

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 calcium scoring thresholds reduce score variability. Using a chest phantom with nine calcifications scanned on a PCD-CT protocol from Part I, images were reconstructed across VMI levels (50–80 keV in 5 keV steps) with threshold adjustments to maintain density, and variability was evaluated. If VMI-based thresholding further stabilizes CAC scores, it would strengthen reproducibility of PCD-CT CAC screening and risk stratification.

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 proposed a protocol to decrease variability. A chest phantom containing nine calcifications was scanned on a PCD-CT system across tube voltages (90 vs 120 kVp), tube currents (dose levels 100% to 25%), slice thicknesses (3 mm vs 1 mm), and quantum iterative reconstruction (IR 1–4), with interscan variability measured across settings. Establishing a low-variability PCD-CT CAC protocol would improve reproducibility of CAC-based cardiovascular risk assessment compared with conventional CT approaches.

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

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Dose optimization & radiation safety (dose–SNR, absorbed dose, protocol efficiency)

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

The study evaluated spectral shaping for extremity photon-counting detector (PCD) CT by estimating organ absorbed dose using Monte Carlo simulations across different source voltage and filtration settings. Spectral shaping combinations reduced organ dose compared with conventional CTDI-based optimization while maintaining image-quality constraints (as assessed in the simulation framework). This supports patient- and organ-specific dose optimization for point-of-care forearm extremity PCD-CT, improving the scientific basis for safer photon-counting CT protocols.

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) across image quality levels (IQLs) in photon-counting CT (PCCT) using adult and pediatric head anthropomorphic phantoms. By scanning phantoms across multiple IQLs and measuring dose metrics (mAs, CTDIvol, DLP, organ doses) alongside SNR in brain parenchyma and bone, the study characterized how SNR changes nonlinearly with increasing dose. These findings support evidence-based selection of IQLs to optimize pediatric and adult head PCCT protocols for image quality while minimizing radiation exposure.

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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Abdominal imaging workflows & quantitative/spectral reconstruction

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

This practical review examined how to maximize the clinical impact of photon-counting CT (PCD-CT) in abdominal imaging, focusing on its spectral/quantitative capabilities and reconstruction strategies. It found that PCD-CT enables flexible retrospective reconstructions such as virtual monoenergetic imaging and material decomposition, which can be tailored to specific abdominal tasks to improve diagnostic utility and dose efficiency. The review’s significance is that it provides actionable implementation strategies for translating PCD-CT’s physics into routine abdominal clinical workflows.

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

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Peripheral vascular imaging (extremity CTA/PAD)

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 optimal isotropic reconstruction conditions could improve visualization of distal vessels and stenoses, enhancing noninvasive PAD assessment with PCD-CT.

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

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Metal artifact reduction & reconstruction optimization (IMAR/UHR-PCCTA)

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

This prospective/clinical study compared iterative metal artifact reduction (IMAR) presets in ultra-high-resolution photon-counting CT angiography (UHR-PCCTA) for 31 lower extremities from 25 patients with total knee endoprosthesis. It found that different IMAR settings measurably affected image quality and the visualization of the popliteal vasculature in the presence of knee arthroplasty metal artifacts. The significance is improved optimization of UHR-PCCTA reconstruction parameters to enhance peripheral artery disease assessment despite prosthesis-related artifacts.

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

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Image reconstruction & denoising (AI denoising, kernels, virtual monoenergetic recon)

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 tested whether deep learning-based denoising (post hoc AI denoising) improves image quality and diagnostic confidence in neurovascular ultrahigh-resolution photon-counting CT angiography (UHR PCD-CTA). In 42 patients undergoing clinically indicated head and neck UHR PCD-CTA, denoising applied to vendor iterative reconstruction (level 4) increased perceived image quality and diagnostic confidence, particularly in lower-neck and artifact-prone regions. The significance is that AI denoising can help realize the diagnostic potential of UHR PCD-CTA by mitigating photon-counting noise limitations.

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

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Musculoskeletal imaging & osteoarthritis research (structural/bone modeling)

The current state of computed tomography in osteoarthritis research.

This narrative review summarized the current state of computed tomography (CT) methods in osteoarthritis (OA) research, focusing on structural assessment and biomechanical modeling. It found that CT enables high-resolution quantification of osteophytes, subchondral bone cysts, sclerosis, and joint space width (JSW), and supports 3D bone shape modeling and dynamic evaluation of joint mechanics when combined with other approaches. The significance is that it consolidates how CT-derived geometric and morphometric biomarkers can strengthen OA research and potentially improve translation to clinical endpoints.

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

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Crystal arthropathies & musculoskeletal mineral detection (CPP/hydroxyapatite)

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 with osteoarthritic hand joints scheduled for finger-joint surgery. The reference standard combined 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 would support more precise, noninvasive identification of crystal types that drive diagnosis and management of crystal arthropathies.

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

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ENT/temporal bone & conductive hearing loss interpretation

Conductive hearing loss and normal CT: a clinical perspective.

This clinical perspective reviewed literature and presented illustrative cases linking audiology to photon-counting detector CT (PCD-CT) findings in patients with conductive hearing loss but 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 emphasizes integrating audiologic testing with PCD-CT interpretation and considering non-CT-visible etiologies when temporal bone CT does not explain conductive hearing loss.

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

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Pediatric imaging & virtual non-calcium techniques (pseudo-tumor differential)

Orbital Imaging Modalities and Recent Updates.

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 demonstrated the role of virtual non-calcium imaging on a photon-counting CT scanner. Using virtual non-calcium (a low-dose photon-counting technique), the lesion was characterized in a way that supported correct diagnosis and straightforward interpretation. The clinical significance is that virtual non-calcium photon-counting CT can reduce diagnostic pitfalls in pediatric pseudo-tumor presentations that mimic malignancy on conventional imaging.

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

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Injection/contrast quantification & iodine delivery (ID quantification, IDR protocols)

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) using photon-counting CT, first calculating an ideal IDR (IDRIDEAL) targeting a 500 HU goal in 55 keV reconstructions and then deriving an IDR formula using demographic predictors. In two validation groups with different injection rates (3.5 and 5.0 mL/s), coronary enhancement was quantified and tested for equivalence within a predefined HU range (500 ± 50), with a reader study evaluating perceived coronary enhancement. A validated IDR protocol could improve consistency of coronary enhancement on photon-counting CT, potentially enabling more reliable image quality across patients and injection regimens.

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

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

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

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

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Imaging informatics & reporting impact (PACS-based recommendation rates)

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 dual-energy CT (DECT) and single-energy CT (SECT) in outpatient contrast-enhanced examinations. Examinations lacking virtual noncontrast and iodine map images for PCCT/DECT were excluded, and radiology reports were reviewed for whether follow-up imaging was recommended and the stated reasons, with pairwise comparisons across scanner types. 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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Generated automatically on July 04, 2026. Covers PubMed articles published June 27, 2026 – July 04, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.