What’s New in Photon Counting CT?

September 29, 2026 · 6 articles · 9 research themes · covering September 22, 2026 – September 29, 2026

Overview

Across this week’s set of studies, photon-counting CT (PCCT) emerges as a recurring platform for improving quantitative imaging—either by enhancing measurement reliability, enabling better spectral/energy-based quantification, or reducing radiation dose while maintaining diagnostic quality. Several articles directly address how PCCT’s detector and spectral capabilities translate into more robust clinical measurements, including reproducible intracranial aneurysm morphologic sizing, improved dose efficiency in multiphase 4D parathyroid CT, and more accurate hepatic fat-fraction estimation across different body sizes using virtual monochromatic imaging settings.

A second dominant theme is the movement from “better images” toward validated biomarkers and clinically actionable decision support. The systematic review consolidates evidence for CT-derived myocardial extracellular volume (ECV) as a quantitative fibrosis biomarker, highlighting the potential for photon-counting CT to further improve performance and integration into routine cardiac CT workflows. In neuroimaging, repeat myelography after an initial negative/nonlocalizing study is evaluated for its real-world diagnostic yield, with predictors of positivity guiding whether additional invasive testing is warranted.

Finally, the collection also showcases PCCT’s broader research utility beyond routine diagnostics: energy-resolved photon-counting CT enables noninvasive, spatiotemporal mapping of heterogeneous cryoprotectant diffusion in tissue-mimicking hydrogels. Together, these studies illustrate a field trend toward quantitative, reproducible, and dose-conscious imaging—supported by spectral methods and validated against clinical or reference standards—while expanding PCCT’s role into translational and mechanistic research.

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Photon-Counting CT vs Conventional CT (Dose & Image Quality Comparisons)

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

This AJNR study compared photon-counting CT (PCCT) with conventional energy-integrating detector CT (EIDCT) for 4D parathyroid imaging, focusing on radiation output (CTDIvol and DLP) and image quality (signal-to-noise ratio and contrast-to-noise ratio). The key finding was that PCCT provided improved dose efficiency and maintained or improved image quality metrics relative to EIDCT in the 4D parathyroid CT setting. Clinically, this supports adopting PCCT for parathyroid 4DCT to reduce cumulative radiation from multiphase acquisitions while preserving 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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Intracranial Vascular Imaging & Aneurysm Assessment

3D Volume Rendering of Ultrahigh-Resolution Photon-Counting Detector CT Angiography for Preoperative Assessment of Intracranial Aneurysms: Initial Experience.

This retrospective study in 21 patients (32 intracranial aneurysms) evaluated whether ultrahigh-resolution photon-counting detector CT angiography (UHR PCD-CTA) combined with 3D volume rendering (3DVR) yields reliable aneurysm morphologic assessment and reproducible size measurements, with two neurosurgeons reading 2D and 3DVR datasets. The key finding was that the UHR PCD-CTA 3DVR workflow provided consistent image quality and reproducible aneurysm characterization/size measurements across observers. Clinically, this supports using UHR PCD-CTA with 3DVR for preoperative planning of intracranial aneurysms by improving measurement reliability while leveraging photon-counting CT’s higher detector performance.

Tóth A, Silbergleit M, Al Kasab S et al. · AJNR. American journal of neuroradiology · (2026) · View on PubMed ↗

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Spontaneous Intracranial Hypotension & Repeat Myelography

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

This AJNR retrospective single-center study evaluated 71 patients with suspected spontaneous intracranial hypotension who had an earlier negative or nonlocalizing myelogram (and 13 with an unresolved suspicious target after treatment) to determine the clinically supported diagnostic yield of repeat myelography and predictors of positivity. The key finding was the measured proportion of repeat studies classified as definite or suspicious (versus negative) and identification of imaging/clinical features associated with a higher likelihood of a positive repeat examination. Clinically, it informs decision-making on whether to pursue repeat myelography after an initial negative study in patients where a CSF-venous fistula may be present.

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

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Cardiac Imaging Biomarkers (Myocardial ECV & Fibrosis)

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 (EuroAIM framework) synthesized current evidence on CT-derived myocardial extracellular volume (ECV), emphasizing its clinical utility and the emerging role of photon-counting CT for ECV estimation. The key finding was that CT-derived myocardial ECV is increasingly supported as a quantitative biomarker of diffuse fibrosis, with CMR serving as the reference standard, and that photon-counting CT may further improve measurement performance and integration into routine cardiac CT workflows. Scientifically, it consolidates the state of validation and highlights where photon-counting CT could reduce barriers to broader adoption of ECV as an imaging biomarker.

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

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Quantitative Imaging of Tissue Composition (Fat Fraction)

Uniform quantification of hepatic fat fraction across body sizes using photon-counting CT.

This European Journal of Radiology study used anthropomorphic liver phantoms with known hepatic fat fractions (5%–40%) embedded in medium- and large-body-size abdominal models to determine common photon-counting CT (PCCT) virtual monochromatic imaging (VMI) settings for accurate hepatic fat fraction quantification. The key finding was that specific PCCT VMI energy settings (40–190 keV, 1-keV increments) minimized relative root-mean-square error across body sizes, enabling uniform fat-fraction estimation despite changes in patient habitus. Scientifically and clinically, it provides a practical calibration strategy for robust, body-size–independent hepatic fat quantification using PCCT.

Li X, Kallman C, Zhang D et al. · European journal of radiology · (2026) · View on PubMed ↗ · Free PDF ↗

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Imaging-Based Diffusion & Transport Kinetics (Cryopreservation)

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

This Physics in Medicine and Biology study used photon-counting multi-spectral x-ray CT (MSCT) with an empirical photon-energy bin selection algorithm to quantify how a ternary cryoprotectant mixture—dimethyl sulfoxide (DMSO), glycerol, and water—diffuses into a hydrogel tissue surrogate mimicking human muscle diffusion. The key finding was that multi-spectral photon-counting CT enabled quantitative, spatiotemporal mapping of heterogeneous cryoprotectant transport, with energy-bin selection improving sensitivity to the diffusing components. Scientifically, it demonstrates a noninvasive imaging approach for measuring diffusion kinetics in complex mixtures, which could inform optimization of cryopreservation protocols.

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

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Generated automatically on September 29, 2026. Covers PubMed articles published September 22, 2026 – September 29, 2026. Summaries are AI-generated; always consult the original publication for clinical or research decisions.