Caristo Diagnostics vs Heartflow (2026)
These two measure different biology from the same coronary CT scan, so this is less either or than a question of which risk you are missing. Heartflow computes physiology: FFRCT estimates the functional significance of each lesion, supported by the ACC AHA Chest Pain Guideline and the largest evidence base in this index, more than 600 peer reviewed publications and 400,000 plus patients in clinical use. Caristo measures inflammation: its FAI Score quantifies the fat attenuation gradient in perivascular tissue, and in the Lancet published ORFAN registry, patients with no or minimal plaque and zero calcium but the highest coronary inflammation carried roughly 9.5 to 11 times the cardiac mortality risk of those with minimal inflammation, which is risk conventional assessment calls clean. The US regulatory asymmetry decides most purchases: Heartflow's platform is cleared and guideline embedded, while Caristo's inflammation product is cleared in the UK, EU, and Australia but remains pending FDA clearance for US clinical use, holding a Category III tracking code rather than an established payment code; its FDA cleared US product is CaRi-Plaque, which competes in plaque quantification, not inflammation. If your failure mode is lesion significance in symptomatic patients, start with Heartflow. If your failure mode is the patient whose scan looks clean, and you practice where FAI is cleared, start with Caristo.
- 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, a signal plaque and physiology tools do not measure.
- Independent evidence posture: ORFAN externally validated the prognostic algorithm in an NHS population, CRISP-CT established incremental value beyond traditional risk factors, and an ESC 2025 late breaker reported FAI Score predicting cardiac death beyond hsCRP.
- You practice in the UK, EU, or Australia: CaRi-Heart FAI Score is regulatory cleared in those markets today, and CaRi-Plaque holds FDA clearance in the US plaque quantification set.
- Guideline embedded physiology: FFRCT is supported by the ACC AHA Chest Pain Guideline, the recognition no competitor in the lane holds.
- Evidence maturity without rival: more than 600 peer reviewed publications and 400,000 plus patients in clinical use across landmark trials from SCOT HEART to the DECIDE registry.
- One platform across the pathway in cleared markets: stenosis detection, physiology, plaque quantification, and intervention planning under Heartflow One.
This comparison is published by AI Health Index, an independent research platform that compares healthcare AI vendors objectively. Caristo Diagnostics and Heartflow 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 | Heartflow |
|---|---|---|
| Primary category | Radiology & Imaging AI | Radiology & Imaging AI |
| Founded | Not recorded | 2007 |
| Headquarters | Oxford, England, United Kingdom | Mountain View, California, United States |
| Website | caristo.com | heartflow.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 Heartflow, Caristo Diagnostics grades higher on Model and Technology Transparency, AI Governance and Bias Disclosure and AI Liability and Recourse. 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 Heartflow its top capability grade on several axes, including AI Centrality, Clinical and Operational Evidence and Security Certifications and Trust Center. Set against Caristo Diagnostics, Heartflow grades higher on several axes, including Model Supply Chain Disclosure, AI Safety and PHI Stewardship and HIPAA and BAA Posture. 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 Heartflow?
On the axes where the AI Health Index separates them, Caristo Diagnostics grades higher on Model and Technology Transparency, AI Governance and Bias Disclosure and AI Liability and Recourse, and Heartflow grades higher on several axes, including Model Supply Chain Disclosure, AI Safety and PHI Stewardship and HIPAA and BAA Posture. Heartflow 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 Heartflow differ most?
The widest separation the AI Health Index records between Caristo Diagnostics and Heartflow is on Model and Technology Transparency, where Caristo Diagnostics grades A and Heartflow 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 Heartflow grade the same?
The AI Health Index grades Caristo Diagnostics and Heartflow the same on several axes, including AI Centrality, Autonomy and Oversight Model and Clinical and Operational Evidence. 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.
Publication and patient counts come from each vendor's own materials; ORFAN and CRISP-CT results should be read from the published studies. The regulatory split is the decisive fact: Caristo's inflammation product is pending FDA clearance for US clinical use and holds a Category III emerging technology code, a tracking code without established payment, while its US cleared product is plaque quantification.
Heartflow's Plaque and RoadMap functions are cleared in the US and four other countries only, and Heartflow's own dossier describes FFRCT reimbursement as inadequate, a candid disclosure this index credits. Neither vendor publishes pricing.