What’s New in Photon Counting CT?

September 25, 2026 · 12 articles · 12 research themes · covering September 18, 2026 – September 25, 2026

Overview

This week’s PubMed highlights show photon-counting CT (PCCT/PCD-CT) moving from “better images” toward “more reliable measurements” across multiple clinical domains. Several studies focus on diagnostic performance and surveillance: PCCT hemodynamic assessment after TAVI for prosthetic valve dysfunction, PCCT coronary angiography for in-stent restenosis, and PCCT temporal bone imaging for otosclerosis—each benchmarking against conventional imaging or clinical standards. Complementing these, a systematic review consolidates evidence for CT-derived myocardial extracellular volume (ECV) as a fibrosis biomarker, positioning photon-counting CT as a promising route to improve quantitative accuracy and reduce methodological variability relative to cardiac MRI reference standards.

A second dominant theme is dose efficiency and protocol tailoring. Work comparing PCCT with conventional CT for 4D parathyroid imaging emphasizes reduced radiation without loss of objective image quality, while studies in lung imaging and pediatric chest imaging map how far ultra-low-dose protocols can be pushed before quantitative lung phenotyping (e.g., emphysema and density metrics) and reader-rated interpretation degrade. Together, these results frame a practical message: photon-counting detectors can enable lower dose, but the “dose–noise–quantification” trade space must be characterized for each task.

Finally, the digest underscores PCCT’s expanding role beyond standard anatomy. Research on multispectral photon-counting CT quantifies heterogeneous diffusion of cryoprotectants in tissue-mimicking surrogates, while preclinical multimodal imaging demonstrates how acquisition settings can modulate fluorescence/activation of terbium-doped nanoparticles for theranostic applications. Post-procedure imaging studies for cochlear implants further reinforce that optimized PCCT protocols can preserve diagnostic image quality while reducing radiation—supporting broader clinical adoption of photon-counting technology.

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Photon-Counting CT for Multispectral/Material Transport Quantification

Photon counting multi-spectral x-ray computed tomography of multi-component cryoprotectant diffusion into tissue surrogate.

The study investigated whether photon-counting multi-spectral x-ray CT (MSCT) with an empirical photon-energy bin selection algorithm can quantify heterogeneous diffusion of a ternary cryoprotectant mixture (dimethyl sulfoxide [DMSO], glycerol, and water) into a hydrogel tissue surrogate mimicking human muscle diffusion. The authors reported that MSCT enabled non-invasive, spatiotemporal measurement of the cryoprotectant distribution during diffusion, with energy-bin selection providing quantitative sensitivity to the heterogeneous transport. This supports photon-counting MSCT as a quantitative tool for characterizing cryoprotectant delivery relevant to cryopreservation and tissue engineering.

Ali AM, Parker JT, Consiglio AN et al. · Physics in medicine and biology · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Parathyroid 4D Imaging

Quantitative Evaluation of Image Quality Improvement and Reduced Radiation Output with Photon-Counting CT in 4D Parathyroid Imaging.

This study compared photon-counting CT (PCCT) versus conventional energy-integrating detector CT (EIDCT) for 4D parathyroid imaging in patients undergoing repeated noncontrast and multiphase contrast-enhanced acquisitions, focusing on radiation output (CTDIvol, DLP) and image quality (SNR, contrast-to-noise ratio). The key finding was that PCCT can reduce radiation exposure while maintaining or improving objective image quality metrics in the complex neck anatomy required for 4DCT. Clinically, this suggests PCCT may improve dose efficiency for parathyroid localization without sacrificing diagnostic performance.

Arizono E, Buch K, Kelly HR et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗ · Free PDF ↗

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CT Imaging for Spontaneous Intracranial Hypotension (Myelography)

Diagnostic Yield of Repeat Myelography After an Initial Negative Study in Patients With Suspected Spontaneous Intracranial Hypotension.

Researchers evaluated the diagnostic yield of repeat myelography after an initially negative myelogram in 71 patients with suspected spontaneous intracranial hypotension, and additionally assessed a subgroup of 13 patients with persistent unresolved suspicious targets after treatment. Repeat myelography produced a clinically supported proportion of positive (definite or suspicious) findings, and the study identified imaging/report features associated with positivity. This informs decision-making on whether to pursue repeat spinal imaging for suspected CSF-venous fistula when the first myelogram is negative or nonlocalizing.

Callen AL, Jenkins K, Bhaumik D et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗

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Photon-Counting CT for Cardiac Biomarkers (ECV/Fibrosis)

CT-derived myocardial extracellular volume: current evidence, clinical utility, and the emerging role of photon-counting CT-a systematic review.

This systematic review synthesized current evidence on CT-derived myocardial extracellular volume (ECV) as a biomarker of diffuse fibrosis, emphasizing clinical utility and the emerging role of photon-counting CT (PCCT) relative to cardiac magnetic resonance as the reference standard. The authors concluded that CT-derived ECV is increasingly feasible and potentially integrable into routine cardiac CT, while highlighting methodological variability and the promise of PCCT for improved quantitative accuracy. Scientifically, the review frames how PCCT could strengthen ECV measurement reliability for diffuse myocardial disease assessment.

D’Argenzio J, Stucchi F, Tambè V et al. · European radiology experimental · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Pediatric Imaging

Pediatric Chest Photon-counting CT: Dose and Noise Behavior of Clinical Sn100 kVp and 90 kVp Protocols across Image Quality Levels - a Phantom Study.

In a phantom study, the authors compared pediatric chest photon-counting CT (PCCT) protocols—clinical Sn100 kVp ultra-high resolution (UHR) with tin filtration versus non-tin-filtered 90 kVp standard resolution—across multiple image quality levels using three anthropomorphic pediatric phantoms (1, 5, and 10 years). They found that dose and noise behavior differed by protocol and image quality level, with the tin-filtered Sn100 kVp approach showing distinct noise/dose trade-offs relative to 90 kVp as image quality demands increased. This supports protocol optimization for pediatric PCCT to achieve adequate image quality while minimizing radiation dose.

Klüner LV, Zensen S, Peuster H et al. · RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin · (2026) · View on PubMed ↗

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Photon-Counting CT for Theranostics and Nanoparticle Activation/Fluorescence

Optimizing x-ray based multimodal imaging: investigating dose dependency and modulation of fluorescence emission from GdF3nanoparticles doped with terbium using spectral photon counting CT.

This x-ray multimodal imaging study investigated how spectral photon-counting CT acquisition parameters affect fluorescence emission and x-ray-induced activation of terbium-doped gadolinium fluoride nanoparticles (GdF3:Tb), including surface-functionalized GdTbF3 nanoparticles. The key finding was that fluorescence output and imaging performance depend on photon-counting CT irradiation and acquisition settings, enabling optimization of activation and imaging protocols. These results advance the scientific basis for combining photon-counting CT with nanoparticle fluorescence for theranostic applications.

Akl P, Gautheron A, Antonuccio MN et al. · Physics in medicine and biology · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Coronary and Vascular Imaging

In vivo coronary stent evaluation using photon-counting computed tomography: diagnostic performance.

The study assessed diagnostic performance of photon-counting CT coronary angiography for detecting in-stent restenosis (ISR ≥ 50%) and evaluating in-stent lumen image quality in 141 consecutive patients with coronary stents, comparing PCCT with energy-integrating detector CT (EID-CT) against invasive coronary angiography. The authors reported that PCCT provided diagnostic performance and image quality for ISR detection that were competitive with (and in key measures potentially superior to) EID-CT. Clinically, this supports PCCT as a promising technology for more accurate, higher-quality coronary stent evaluation with potential dose-efficiency benefits.

Lacaita PG, Bilgeri V, Spitaler P et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Otologic/Temporal Bone Diagnostics

Photon-counting CT for preoperative assessment of stapes footplate fixation in otosclerosis.

This retrospective case series studied photon-counting CT (PCCT) of the temporal bone in 18 patients with surgically confirmed otosclerosis to characterize imaging findings of stapes footplate fixation and to quantify missed diagnoses on initial radiology reports. The key finding was that PCCT demonstrated specific correlates of fixation (e.g., increased thickness and/or hypoattenuation of the stapes footplate) and that initial reports sometimes failed to identify these findings. This is clinically significant because it suggests PCCT may improve preoperative detection of stapes fixation and reduce diagnostic oversight in otosclerosis.

Arora M, Seyedsaadat SM, Breen JT et al. · European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery · (2026) · View on PubMed ↗

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Photon-Counting CT for Post-Procedure/Implant Imaging

Photon-counting detector CT versus cone-beam CT for postoperative cochlear implant imaging.

Researchers compared photon-counting detector CT (PCD CT) and cone-beam CT (CBCT) for postoperative cochlear implant imaging using 224 retrospective datasets (112 PCD CT scans across regular, low, and ultra-low dose protocols; 112 120-kV CBCT scans). The study found differences in image quality and contrast-to-noise ratio (CNR) between modalities and dose protocols, with objective and subjective image-quality measures favoring specific PCD CT dose settings. This supports selecting an optimized PCCT protocol that can reduce radiation while preserving diagnostic image quality after cochlear implantation.

Burck I, Tillmanns M, Bernatz S et al. · European journal of radiology · (2026) · View on PubMed ↗

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Photon-Counting CT for Lung Quantitative Phenotyping

Quantitative and qualitative lung parameters in photon-counting CT: comparison of ultra-low-dose with standard low-dose protocols.

This prospective study evaluated how ultra-low-dose (ULD) photon-counting CT (PCCT) affects quantitative and qualitative lung assessment compared with same-session low-dose (LD) PCCT in 101 patients undergoing mixed-indication chest CT. The key finding was that ULD altered quantitative lung metrics derived from automated quantitative CT (QCT)—including noise index, airway segmentation metrics, emphysema index, mean lung density, and Percentile15—while also impacting reader-rated image quality and airway/emphysema visualization. Scientifically and clinically, the results define how far dose can be reduced in PCCT before quantitative lung phenotyping and qualitative interpretation become unreliable.

Kroschke J, Jungblut L, von Stackelberg O et al. · European radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Cardiac Structural Assessment

Photon-counting detector CT for prediction of valve dysfunction after transcatheter aortic valve implantation: Comparison with echocardiography.

This retrospective single-center study evaluated whether time-resolved photon-counting detector CT (PCD-CT)–derived hemodynamic parameters can predict prosthetic valve dysfunction after transcatheter aortic valve implantation (TAVI) in post-TAVI patients, compared with echocardiography. The key finding was that PCD-CT functional assessment showed diagnostic accuracy for identifying valve dysfunction, with performance benchmarked against echocardiographic evaluation. Clinically, this supports PCCT as a noninvasive imaging approach that can provide both anatomic and hemodynamic information to improve post-TAVI surveillance and decision-making.

Hyska S, Osoria-Velasquez J, Hagar MT et al. · Journal of cardiovascular computed tomography · (2026) · View on PubMed ↗ · Free PDF ↗

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Photon-Counting CT for Atrial Fibrillation Risk Stratification

Epicardial adipose tissue in paroxysmal and persistent atrial fibrillation ablation using photon counting CT and automated 3D atrial segmentation: The Prospective AFAT Study.

In the prospective AFAT study, 210 adults with paroxysmal or persistent atrial fibrillation undergoing first-time catheter ablation underwent preprocedural photon-counting CT (PCCT) with semiautomated 3D biatrial segmentation to quantify epicardial adipose tissue (EAT) and relate it to arrhythmia recurrence. The study found that volumetric EAT measures derived from PCCT/3D segmentation were associated with recurrence after ablation. Scientifically and clinically, this suggests that PCCT-based EAT quantification could help risk-stratify patients and refine prediction of AF recurrence following catheter ablation.

Erhard N, Bahlke F, Prommersberger S et al. · Heart rhythm · (2026) · View on PubMed ↗ · Free PDF ↗

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Generated automatically on September 25, 2026. Covers PubMed articles published September 18, 2026 – September 25, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.