Weekly AI digest
Radiology & medical imaging AI · week of 20 to 26 September 2026
194 peer-reviewed papers · 4 industry and regulatory items · conference and KOL highlights. Adapted from my weekly intelligence report. Full report: FR (PDF) · EN (PDF) · RU (PDF).
Governance takeaway
What to do about it this week
This week draws the line between accuracy evidence and deployment evidence unusually clearly. A Nature Medicine screening model arrives with 12-center validation on 80,612 patients, real-world calibration and a prospective cohort, while the week's meta-analyses and benchmarks, LVO triage on noncontrast CT, cerebral microbleed detection, LLM decision support, all stop at retrospective accuracy, and say so.
The action for a radiology leader: add one line to every AI proposal your committee reviews, classifying its evidence as accuracy-based or workflow-based, and refuse to approve an unsupervised or workflow-changing role on accuracy-only evidence. A bounded human-in-the-loop role with a prospective monitoring plan is the correct ceiling until the workflow evidence exists.
Regulation & AI Act watch
a2z Radiology AI clears 10 more abdomen-pelvis CT triage findings
Cleared on 21 September for triage and notification (CADt) of 10 additional suspected findings on abdominopelvic CT, from obstructing ureteral stone to solid-organ traumatic injury, bringing the portfolio to 17 findings across two devices, with Breakthrough Device designation attached. The announcement cites no peer-reviewed performance publication for the new findings, and a triage clearance is not a detection claim. The single most important vendor question: per-finding sensitivity and specificity with the test-set composition behind them, and the expected alert volume per 1,000 studies in a case mix like yours.Merge launches MergeIQ, an AI layer inside its enterprise imaging platform
Launched 22 September with two workflow applications that rank relevant prior reports and retrieve historical findings inside the reading workflow, on vendor launch materials only. These are workflow tools rather than diagnostic devices, but silent model updates inside platform layers are exactly the change class AI inventories miss. The key vendor question: how the embedded models are versioned, and whether retrieval errors are logged and auditable.NVIDIA releases NV-Reason-CT, an open vision-language model for 3D CT reasoning
Released 23 September as an open-weights developer model that drafts structured CT reports with explicit chain-of-thought reasoning, carrying no regulatory status. Products wrapping open CT reasoning models will now reach procurement faster. The key question for any vendor building on it: which claims were validated on the product itself rather than inherited from the base model's publications.Leica Biosystems adds Tempus Paige AI applications to the Aperio AI Store
Announced 24 September: Paige PanCancer Detect and the Paige Prostate suite join Leica's digital pathology platform, explicitly research use only in this channel. An RUO tool inside a clinical-adjacent platform is a boundary that needs policing. The key question: what keeps RUO outputs out of clinical decision paths, and who audits actual usage.
Evidence you can use
Selected from 194 papers indexed in PubMed this week.
Large-scale esophageal cancer screening through noncontrast computed tomography and artificial intelligence
Nature Medicine, 22 September 2026AI Decision Support for Emergency Triage of Large Vessel Occlusion Using Noncontrast Computed Tomography: Systematic Review and Bayesian Diagnostic Test Accuracy Network Meta-Analysis
Journal of Medical Internet Research, 24 September 2026RadCoT: a Radiological Chain-of-Thought framework for enhanced error detection in radiology reports
European Radiology Experimental, 22 September 2026Safety-Oriented Benchmarking of Large Language Models in Risk-Based Management of Abnormal Cervical Screening Results: Scenario-Based Benchmark Study
Journal of Medical Internet Research, 22 September 2026Accuracy of Deep Learning in Detecting Cerebral Microbleeds: Systematic Review and Meta-Analysis
Journal of Medical Internet Research, 21 September 2026MRI-based fetal gestational age estimation using a structure-aware self-supervised network
European Radiology, 21 September 2026Biphasic CT clustering-based habitat radiomics predicts WHO/ISUP nuclear grade in clear cell renal cell carcinoma
Abdominal Radiology, 22 September 2026Foundation Models in Ophthalmic Artificial Intelligence: Current Status and Future Directions
IEEE Journal of Biomedical and Health Informatics, 22 September 2026
Post-market signal
The strongest post-market evidence of the week came from endoscopy. Cosmo announced results of the CADeNCE study (Dominitz et al., Gastroenterology) on 21 September: a cluster-randomized quality-improvement evaluation of the GI Genius colonoscopy CADe system across more than 334,000 procedures by 816 endoscopists at 139 US Veterans Health Administration facilities. CADe availability was associated with 22 percent higher odds of adenoma detection (adjusted OR 1.22; adenoma detection rate 50.7 to 54.9 percent), with benefit across all baseline detection levels. This is what post-market evidence should look like: randomized, national scale, run on the deployed system in routine practice. One detail belongs in every monitoring plan: the study ran on an earlier software generation than the currently marketed version, a reminder that post-market evidence attaches to a version, not a product name.
A second item is commentary rather than an imaging post-market event: a critical-care practice newsletter (25 September) pulled together the emerging literature on decommissioning deployed clinical AI, including radiology's JACR off-boarding framework and an NEJM AI analysis of the measurement trap in which a model that changes outcomes corrupts its own monitoring statistics. The transferable points: require a written exit and transition plan before any tool goes live, track vendor end-of-support dates by name, and treat silent version updates as the most common and least visible exit mode.
Playbook snippet
One step for your AI committee
Anchor: EU AI Act Article 12 (record-keeping) and Article 19 (automatically generated logs).
Step: At procurement, ask the vendor in writing what the system logs, for how long, in what format, and whether you can export it without their involvement. If the answer is a dashboard, the answer is no. Add the log-export clause to the contract before signature, not after go-live.
Why: Every post-market obligation downstream assumes you can reconstruct what the model saw and said on a given date. Retrofitting logging after deployment is a contract renegotiation, not a configuration change.
Worked example: Zhou J et al. show what retained case-level outputs buy you: EAGLE's real-world calibration on 35,402 scans cut false positives 72.7 percent while preserving sensitivity, an adjustment only possible because outputs across three centers could be re-analyzed after the fact. Demand the same reconstruction capability from any tool you deploy. Nature Medicine, 22 September 2026.
From the field
The societies spent the week on governance infrastructure. The Royal College of Radiologists published its reading of the UK National AI Commission's recommendations on healthcare AI regulation, confirming it is working on proposals for a national post-deployment monitoring system. RSNA announced a RadLex initiative to standardize imaging series naming, the unglamorous metadata layer whose inconsistency silently breaks deployed AI pipelines.
Reimbursement moved too. At the September AMA CPT Editorial Panel, ACR and five partner societies requested a Category III code for a five-year AI-derived breast malignancy risk score from screening mammography, the first step toward reimbursed AI risk stratification. The ESR Patient Advisory Group placed cardiovascular imaging at the center of the EU Safe Hearts Plan.
Among the voices, Nina Kottler posted a widely shared three-part thesis: responsible AI requires lifecycle governance because validation at deployment is not enough, scaled governance requires payment models that fund monitoring infrastructure rather than only the AI product, and AI expands radiology's role only if the specialty owns validation and clinical meaning. Curt Langlotz amplified Johns Hopkins' new NIH R01 for detecting three abdominal cancers on routine CT, the same early-detection territory as this week's Nature Medicine esophageal screening paper.
Woojin Kim lectured at Brown on generative and agentic AI in medical imaging, and Amine Korchi reminded his readers that a radiologist's workload is a 100-line worklist invisible to everyone outside the reading room, the capacity strain that drives both AI adoption and burnout.
Source articles are indexed in PubMed with verified DOIs. Manuscript-stage work is excluded. The full weekly report is produced in French.
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