HealthTech NHS AI Radiology Triage -- MHRA Class IIa

Class IIa requirements

• 1UK Notified Body (BSI Assurance UK) technical file review,
• 2IEC 62304 Class B documentation,
• 3ISO 14971 risk management,
• 4clinical evaluation (3-month prospective validation -- 500 cases, sensitivity and specificity per pathology),
• 5UKCA marking,
• 6MHRA DESH registration,
• 7Post-Market Surveillance Plan.

Key standards for radiology AI

Standard 1 (AI triage prioritises worklist order -- does not diagnose independently), Standard 2 (training data demographics documented), Standard 3 (which pathologies AI detects explicitly documented), Standard 8 (AI confidence score and highlighted image region shown -- not binary flag), Standard 14 (quarterly performance review -- sensitivity/specificity tracked in production).

Demographic bias

sensitivity across age groups, sex, BMI documented.

Primary hazard

AI de-prioritising urgent finding.

Design

• 1AI is advisory -- radiologist retains clinical responsibility,
• 2AI cannot move a study below standard priority (can elevate to urgent, never demote),
• 3all studies reviewed regardless of AI score,
• 4urgent threshold conservatively set (sensitivity >98% for pneumothorax/intracranial haemorrhage),
• 5radiologist override recorded for continuous learning.

Integration

• 1DICOM C-STORE listener (studies from CT/MRI/X-ray),
• 2AI inference (ResNet-50 fine-tuned -- <10 seconds per study),
• 3DICOM SR (AI score plus highlighted region attached to study),
• 4worklist re-prioritisation (HL7 ORM update to RIS),
• 5radiologist interface (AI overlay in Sectra IDS7 -- shown while reporting, not before, to avoid anchoring bias).