Caristo Diagnostics vs Elucid (2026)
Two vendors that both refuse the Hounsfield threshold shortcut, measuring what conventional plaque volume misses from different angles. Caristo measures inflammation: its FAI-Score quantifies the perivascular fat attenuation gradient, and in the Lancet published ORFAN registry, patients with minimal plaque and zero calcium but the highest inflammation carried roughly 9.5 to 11 times the cardiac mortality risk. Elucid measures tissue composition: PlaqueIQ classifies plaque against carotid endarterectomy histopathology co registered to CTA, interpreting spatial tissue distribution where attenuation values overlap, and it names lipid rich necrotic core as its target. Both earn an A on model transparency for publishing a checkable mechanism, which makes this a genuine question of which risk signal you want rather than which vendor is more credible. The US split decides availability: Elucid's core product is FDA cleared with Medicare contractor and commercial coverage, while Caristo's inflammation product is pending FDA clearance and holds only a Category III tracking code. If your failure mode is the clean looking scan and you practice where FAI is cleared, start with Caristo. If your failure mode is confident plaque composition with resolved US coverage, start with Elucid, noting its analyst segmentation step is not fully autonomous.
- The clean scan is your blind spot: in the Lancet published ORFAN registry, patients with minimal plaque and zero calcium but high coronary inflammation showed roughly 9.5 to 11 times the cardiac mortality risk, biology Elucid's plaque composition analysis does not measure.
- A published causal chain from biology to risk score, graded A on model transparency, matching Elucid's own A for its histology co registration mechanism, so both vendors let you check the method rather than trust an accuracy claim.
- Independent external validation: ORFAN validated the prognostic algorithm in an NHS population in routine clinical care, the specific generalisation test most imaging AI never faces.
- Ground truth against tissue: PlaqueIQ's networks were trained on carotid endarterectomy histopathology co registered to CTA, classifying plaque against actual tissue rather than Hounsfield thresholds, marketed as CT Virtual Histology.
- US reimbursement is resolved for the core product: four of seven Medicare contractors extended coverage from November 2024 and United Healthcare aligned from October 2025, where Caristo's differentiating FAI-Score holds only a Category III tracking code in the US.
- Lipid rich necrotic core is the target: spatial interpretation across adjacent voxels where attenuation values overlap between tissue types, extended to carotid stroke risk with an October 2025 launch.
This comparison is published by AI Health Index, an independent research platform that compares healthcare AI vendors objectively. Caristo Diagnostics and Elucid are each graded against the same capability taxonomy, from each vendor's own public materials and the regulatory record, under the AI Health Index verification standard. No vendor pays for placement, and no vendor has reviewed this page. How this evidence is graded
Plain facts
| Fact | Caristo Diagnostics | Elucid |
|---|---|---|
| Primary category | Radiology & Imaging AI | Radiology & Imaging AI |
| Headquarters | Oxford, England, United Kingdom | Boston, Massachusetts, United States |
| Website | caristo.com | elucid.com |
Side by Side
Each record in one paragraph
Written to be quoted whole. Each paragraph states what the AI Health Index verified about the vendor, with the caveats attached. Generated from this pair’s live capability grades, so it moves when a grade moves.
The AI Health Index awards Caristo Diagnostics its top capability grade on several axes, including AI Centrality, Model and Technology Transparency and Clinical and Operational Evidence. Set against Elucid, Caristo Diagnostics grades higher on several axes, including Clinical and Operational Evidence, Security Certifications and Trust Center and AI Governance and Bias Disclosure. Grades reflect evidence the AI Health Index could verify at the last review, so a low grade records disclosure the vendor has not published rather than a capability it has been shown to lack.
Source: AI Health Index, July 2026
The AI Health Index awards Elucid its top capability grade on AI Centrality, Model and Technology Transparency and FDA and Regulatory Status. Set against Caristo Diagnostics, Elucid grades higher on Commercial Transparency. Grades reflect evidence the AI Health Index could verify at the last review, so a low grade records disclosure the vendor has not published rather than a capability it has been shown to lack.
Source: AI Health Index, July 2026
Questions buyers ask
Should we choose Caristo Diagnostics or Elucid?
On the axes where the AI Health Index separates them, Caristo Diagnostics grades higher on several axes, including Clinical and Operational Evidence, Security Certifications and Trust Center and AI Governance and Bias Disclosure, and Elucid grades higher on Commercial Transparency. Caristo Diagnostics leads on the greater share of scored axes, but the split means the decision turns on which constraint is binding rather than on an overall winner.
Where do Caristo Diagnostics and Elucid differ most?
The widest separation the AI Health Index records between Caristo Diagnostics and Elucid is on Clinical and Operational Evidence, where Caristo Diagnostics grades A and Elucid grades B. That axis sits in the AI Capability group, so it should carry the most weight for a buyer whose binding constraint is how much of the work the model itself is trusted to do.
Where do Caristo Diagnostics and Elucid grade the same?
The AI Health Index grades Caristo Diagnostics and Elucid the same on several axes, including AI Centrality, Autonomy and Oversight Model and Model and Technology Transparency. Neither holds an advantage the index can evidence on those axes, so they should not carry weight in a selection between these two.
Related comparisons
Other published head to head assessments involving these vendors or their closest peers. The full set for this category is on the Clinical Decision Support page.
Both grade A on model transparency for publishing a checkable mechanism rather than a proprietary accuracy claim, and both measure something conventional plaque volume misses, Caristo inflammation and Elucid tissue composition. The US regulatory split is the decisive fact: Elucid's PlaqueIQ is FDA cleared with real Medicare contractor and commercial coverage, while Caristo's FAI-Score is pending FDA clearance and holds a Category III tracking code without established payment; Caristo's US cleared product is CaRi-Plaque.
Two workflow cautions: Elucid is not fully autonomous, trained analysts segment the data before classification, and its FFRCT product is pending clearance and not available; Caristo's cloud pipeline does not disclose the extent of any quality control step. ORFAN results should be read from the published study. Neither vendor publishes pricing or data residency terms.