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Radiology · Breast & thyroid ultrasound decision support (CADx)
Koios DS
Koios Medical, Inc.
One of the few AI ultrasound tools cleared for both breast and thyroid, Koios DS has done the harder thing than most catalogue-mates: earned an independent evidence base. Alongside its manufacturer reader studies sit external validations from Duke, Valladolid and European tertiary centres — including a prospective study — that broadly confirm a diagnostic lift, largest for less experienced readers. The same literature is candid about the ceiling: used alone the software trails an expert eye, and its specificity is the recurring question.
Performance Metrics
Clinical Evidence
Koios DS has an unusually layered evidence base for a catalogue lean-to-hero graduation — manufacturer pivotal studies underneath, independent external validations on top, and it is the rare AI ultrasound tool evaluated across two organs. The breast pivotal is Mango and colleagues (Radiology venue AJR, 2020): a multicentre retrospective multireader study in which 15 physicians read 900 breast lesions (roughly half benign, half malignant) with and without the software. Mean reader area-under-curve rose from 0.83 reading ultrasound alone to 0.87 with decision support. It is a competent reader study, and it is also the shape pivotal studies usually take: enriched, retrospective, and closely tied to the manufacturer (an earlier data-presentation study, Barinov 2019, was authored from inside Koios). The thyroid clearance rests on a second multireader study — 15 readers, 650 nodules, a mean reader AUC gain of 0.083 — that was reviewed by the FDA but, as far as could be established this run, never journal-published; it lives in the 510(k) summary rather than the literature. What lifts Koios above a one-study entry is the independent work. A prospective single-centre European study (European Journal of Radiology, 2025; 222 patients, 226 lesions) found the software significantly improved the AUC of every reader, with the largest gain for the junior radiologist (0.786 to 0.864) and a reduction in unnecessary biopsy recommendations. Two independent thyroid cohorts agree on direction: a Valladolid group (Thyroid, 2024; 172 patients) found the system reclassified most mildly-suspicious TI-RADS 3 nodules to lower risk, and a Duke group (Thyroid, 2024; 649 nodules) found performance best when the radiologist read was combined with the software's adapter score, cutting unnecessary fine-needle aspirations. The honest counterweight is specificity. An independent Turkish comparison (European Journal of Breast Health, 2025) reported the software used standalone at 92.5 percent sensitivity but only 35.3 percent specificity — below an experienced radiologist reading unaided — and low specificity recurs as the caveat across the thyroid literature too. The consistent finding is that Koios DS is a decision aid that raises the floor for less experienced readers, not a standalone diagnostician; the published record supports the former claim and actively cautions against the latter.
| Study | Design | n | Sensitivity | Specificity | AUC | Published |
|---|---|---|---|---|---|---|
| Mango VL, Sun M, Wynn RT, Ha R | RetrospectiveRetrospective | 900 | — | — | 0.87 with decision support (vs 0.83 ultrasound alone) | AJR Am J Roentgenol 2020;214:1445–1452 (PMID 32319794). Multicentre retrospective MRMC, 15 physicians, 900 breast lesions (~52% benign / ~48% malignant); breast pivotal-era reader study. |
| Koios Medical (FDA 510(k) K212616 summary — thyroid pivotal; not journal-published) | RetrospectiveRetrospective | 650 | — | — | +0.083 mean reader AUC gain (95% CI 0.066–0.099) | MRMC, 15 readers, 650 thyroid nodules (500 US + 150 EU validation cases); basis of the December 2021 thyroid clearance. Reported in the 510(k) summary; no peer-reviewed publication located. |
| European Journal of Radiology study group (independent, single tertiary centre) | ProspectiveProspective | 222 | — | — | AUC improved for all readers (junior 0.786→0.864, general 0.719→0.781, senior 0.823→0.868; all p<0.001) | Eur J Radiol 2025 (PMID 40031378). Prospective, 222 patients / 226 lesions (39.4% benign / 60.6% malignant), biopsy-bound; independent of the manufacturer. |
| Fernández Velasco P, Pérez López P, Torres Torres B, Delgado E, de Luis D, Díaz Soto G (independent, Valladolid) | RetrospectiveRetrospective | 172 | — | — | — | Thyroid 2024;34(4):510–518 (PMID 38368560). Six clinicians read thyroid ultrasound from 172 patients with histology, with and without the software; 81% of TI-RADS 3 and ~25% of TI-RADS 4 nodules reclassified to lower risk. |
| Ashton J, Morrison S, Erkanli A, Wildman-Tobriner B (independent, Duke) | RetrospectiveRetrospective | 347 | — | — | — | Thyroid 2024;34(11):1379–1388 (DOI 10.1089/thy.2024.0410). 649 nodules from 347 patients, one year consecutive; performance best when radiologist read was combined with the AI-adapter score, reducing unnecessary fine-needle aspirations. |
| Çelebi F, Tuncer O, Oral M, Duymaz T, Orhan T, Ertaş G (independent, Turkey) | RetrospectiveRetrospective | 80 | 92.5% (software standalone) | 35.3% (software standalone) | — | Eur J Breast Health 2025;21(1):33–39 (PMID 39744891). Comparative reader analysis; standalone software trailed an experienced radiologist (98.1% / 58.8%) — carried as the honest specificity caveat. |
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Inside the algorithm
Editorial featureHow Koios DS reaches a verdict.
Five stages — from raw input to verdict — drawn from manufacturer documentation and the public regulatory record.
- INGEST
- NORMALISE
- DETECT
- LOCALISE
- VERDICT
Stage 01 · INGEST
A physician-selected lesion, on a compatible ultrasound.
Koios DS works on diagnostic ultrasound acquired on compatible systems and handled as images. Unlike a triage tool that scans a whole study, it acts on a region the physician chooses — for thyroid, two orthogonal views of a single nodule. It is not indicated for normal-tissue evaluation, post-surgical sites, or images carrying Doppler or elastography overlays, and the reading physician must have completed the prescribed training.
Input
Breast / thyroid ultrasound DICOM
Inference
Per-lesion, on demand
Inside the Auris+ Listing
Five more sections complete this device’s Auris+ Listing.
Decision Ledger
ProPro unlocks a private, cross-vendor log of every case you read on this device — what the AI called, what you concluded, and a one-line reason if you overrode it. Ready for the EU AI Act's deployer logging obligations when they land in 2028.
Clinical Evidence Deep Dive
ProPro unlocks the structured clinical-evidence summary — study count, target patient population, and a tabular accuracy-metrics view drawn from peer-reviewed sources.
Peer-Reviewed Publications
ProPro unlocks the curated peer-reviewed publication list with PubMed cross-links — the citation backbone of every editorial verdict.
Post-Market & Regulatory Conditions
ProPro unlocks the post-market surveillance summary, recall record, and the conditions of approval that bound real-world use.
AI Algorithm Version History
ProPro unlocks the chronological record of algorithm version changes — what changed when, drawn from manufacturer changelogs and regulatory filings.
Regulatory Approvals
K161959
Class II
Safety Record
Z-0820-2020, Koios DS Breast series 1.0 (ClearView-era product): affected versions marketed without sufficient documentation of certain required quality procedures. Quality-management documentation issue, not a device-performance or patient-safety event. Terminated 2020-05-07.
The one recall on record is a resolved documentation matter, not a clinical-harm event. In December 2019 the pre-rebrand product line — Koios DS Breast series 1.0, the ClearView-era software behind the 2016 clearance — was subject to a Class 2 recall (Z-0820-2020) after an internal audit found affected versions had been marketed without sufficient documentation of certain required quality procedures. Urgent Medical Device Recall letters went out on 31 December 2019 and the recall was terminated on 7 May 2020. It concerned quality-management documentation, not device performance or a patient-safety signal, and it predates every current-generation clearance. No FDA safety communication or warning letter for Koios Medical was found in indexed public sources as of July 2026. The MAUDE adverse-event database could not be queried directly from this environment, so the absence of adverse-event reports is "none found in public reporting" rather than an exhaustive audit. As an adjunct that operates on a physician-selected lesion and removes nothing from the worklist, the device's harm surface is bounded by the cleared instruction that management decisions must not rest on its output alone.
Intended Use & Indications
Koios DS is prescription image-analysis software used by trained interpreting physicians as an adjunct to diagnostic ultrasound. For breast, it assists in analysing ultrasound images of adult patients with soft-tissue breast lesions referred for further diagnostic examination; for thyroid, it assists in analysing ultrasound of adult patients with thyroid nodules suspicious for cancer. The physician selects a region of interest (for thyroid, two orthogonal views of a single nodule); the software returns editable lexicon descriptors and a level-of-suspicion read — for breast, a continuous confidence indicator aligned to the four ACR BI-RADS assessment categories, and for thyroid, a risk read aligned to ACR TI-RADS and American Thyroid Association criteria. The cleared use is assistive throughout: it is not indicated for normal-tissue evaluation, post-surgical sites, or images carrying Doppler or elastography overlays, and it requires physicians to complete prescribed training before use. It performs no triage, no worklist prioritisation and no autonomous read.