What’s New in Photon Counting CT?

September 26, 2026 · 8 articles · 8 research themes · covering September 19, 2026 – September 26, 2026

Overview

Across this week’s studies, photon-counting CT (PCCT) and related spectral photon-counting approaches consistently emerge as a route to better diagnostic performance and/or improved dose efficiency compared with conventional energy-integrating CT. Evidence spans clinically oriented comparisons (e.g., 4D parathyroid imaging and coronary CT angiography for in-stent restenosis) as well as protocol-focused work showing how acquisition choices can shift the dose–noise balance—particularly important for pediatric imaging where image quality targets must be met with minimal radiation.

A second dominant theme is quantitative imaging biomarkers and advanced functional mapping. A PRISMA-compliant review synthesizes CT-derived myocardial extracellular volume (ECV) as an increasingly feasible marker of interstitial expansion/diffuse fibrosis, while also highlighting methodological variability and positioning photon-counting CT as a likely next step to improve spectral/contrast robustness. Complementing this, a multispectral photon-counting CT study demonstrates noninvasive, spatiotemporal quantification of heterogeneous cryoprotectant diffusion in a tissue-mimicking hydrogel, supporting PCCT as a tool to optimize cryopreservation by measuring how multi-component agents penetrate.

Finally, the digest highlights expanding clinical reach and translational innovation. Otologic temporal bone PCCT shows promise for detecting otosclerosis-related stapes fixation that may be missed on initial reads. In parallel, follow-up imaging research addresses when repeat myelography is worthwhile after a nonlocalizing first study in suspected spontaneous intracranial hypotension. On the translational side, parameter-dependent fluorescence modulation from surface-functionalized gadolinium fluoride nanoparticles under spectral photon-counting CT irradiation points toward theranostic strategies that couple high-contrast imaging with activation of nanoparticle agents.

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Spectral/Multispectral Photon-Counting CT for Diffusion/Cryopreservation Mapping

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 quantitatively map heterogeneous diffusion of a ternary cryoprotectant cocktail (dimethyl sulfoxide [DMSO], glycerol, and water) into a hydrogel tissue surrogate mimicking human muscle diffusion. The authors reported that MSCT enabled non-invasive, spatiotemporal quantification of the cryoprotectant distribution during diffusion, capturing heterogeneity driven by the multi-component transport. This supports photon-counting MSCT as a quantitative tool for optimizing cryopreservation protocols by measuring how specific cryoprotectants penetrate tissue-like media.

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 vs Conventional CT (Dose & Image Quality)

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 terms of radiation output (CTDIvol and DLP) and image quality (SNR and contrast-to-noise ratio) across the repeated noncontrast and multiphase contrast-enhanced acquisitions. The key finding was that PCCT provided improved dose efficiency and/or image quality relative to EIDCT while addressing the need for high-quality imaging in the anatomically complex neck. Clinically, this suggests PCCT could reduce radiation exposure for patients undergoing 4DCT for parathyroid localization without sacrificing diagnostic image quality.

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

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Repeat/Follow-up Imaging Strategies (Myelography for CSF Leak Syndromes)

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

This retrospective single-center study evaluated the diagnostic yield of repeat myelography after an initial negative myelogram in 71 patients with suspected spontaneous intracranial hypotension, with additional analysis of 13 patients whose earlier suspicious target remained unresolved after treatment. Repeat myelography produced a clinically supported proportion of positive (definite or suspicious) findings, and the study identified imaging/clinical features associated with positivity. Scientifically and clinically, the results help guide whether and when to pursue repeat myelography to detect CSF-venous fistulas (CVFs) when the first study is nonlocalizing.

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

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CT-Derived Myocardial Extracellular Volume (ECV) & Fibrosis Biomarkers

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

This PRISMA-compliant systematic review synthesized current evidence on CT-derived myocardial extracellular volume (ECV) and its clinical utility, focusing on how CT ECV compares with cardiac magnetic resonance as the reference standard. The review found that CT-derived ECV can quantify myocardial interstitial expansion/diffuse fibrosis with growing evidence for clinical applicability, while highlighting methodological variability and the emerging role of photon-counting CT (PCCT) to improve spectral/contrast performance. Overall, it positions CT-derived ECV as an increasingly feasible biomarker and frames PCCT as a likely next step for improving robustness and accuracy.

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 Protocol Optimization (Pediatrics & Image Quality Targets)

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

Using anthropomorphic pediatric phantoms aged 1, 5, and 10 years, this phantom study measured how radiation dose and image noise behave for photon-counting CT (PCCT) across image quality levels when using a clinical tin-filtered Sn100 kVp ultra-high-resolution protocol versus a non-tin-filtered 90 kVp standard-resolution protocol. The key finding was that dose and noise trade-offs differed between the Sn100 kVp tin-filtered and 90 kVp non-tin protocols across image quality levels, informing how protocol choice affects pediatric image quality. This is significant for optimizing pediatric chest PCCT protocols to achieve target image quality while minimizing radiation exposure.

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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Spectral Photon-Counting CT for Nanoparticle Fluorescence Theranostics

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 study investigated how spectral photon-counting CT (SPCCT) acquisition parameters influence x-ray–induced fluorescence emission from surface-functionalized gadolinium fluoride nanoparticles doped with terbium (GdTbF3 nanoparticles; GdF3:Tb) and how dose dependency affects imaging performance. The authors reported that fluorescence modulation depends on SPCCT irradiation/acquisition settings, enabling optimization of activation and imaging protocols for these nanoparticle agents. The work is important for advancing nanoparticle-assisted, photon-counting CT approaches that could combine high-contrast imaging with theranostic activation.

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/Cardiac Applications

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

In 141 consecutive patients with coronary stents undergoing coronary CT angiography, this retrospective single-center study compared photon-counting CT (PCCT) with energy-integrating detector CT (EID-CT) for detecting in-stent restenosis (ISR) ≥50% using invasive coronary angiography as the reference standard. The key finding was that PCCT demonstrated diagnostic performance for ISR detection with improved or comparable in-stent lumen image quality relative to EID-CT. Clinically, this supports PCCT coronary angiography as a promising noninvasive method for evaluating stent patency and restenosis.

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 Imaging (Temporal Bone/Otosclerosis)

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

This retrospective case series assessed photon-counting CT (PCCT) findings for surgically confirmed stapes footplate fixation in otosclerosis in 18 patients who underwent temporal bone PCCT, and it evaluated how often initial radiology reports missed these findings. The study found that PCCT imaging features such as increased stapes footplate thickness and/or hypoattenuation correlated with intraoperative findings, while missed diagnoses occurred on initial interpretation. This is significant because it highlights PCCT’s potential to improve preoperative detection of otosclerosis-related fixation and reduce diagnostic oversight.

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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Generated automatically on September 26, 2026. Covers PubMed articles published September 19, 2026 – September 26, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.