Health & Medical

AI Medical Imaging: How Scans Get a Second Check

By Eri-Tech Global Ltd · Published November 1, 2026 · Last updated November 1, 2026 · 9 min read

A modern, clean MRI scanner room in a hospital facility.
A modern MRI scanner room.

AI medical imaging means using software to help health staff work with pictures of the inside of the body: X-rays, CT scans, MRI scans and ultrasound images. The software does not take the picture, and it does not make the final decision. It reads an existing scan, points to patterns it has seen before, and passes that extra check to a trained person.

This article is part of the 'AI in Every Sector' series, looking at how AI is used in one sector at a time. Here the sector is health care, and the focus is narrow: what AI does around a scan, what it does well, and where a human check still matters most.

A radiographer, trained to use scanning equipment, takes it. A radiologist, a doctor trained to read images, studies it and reports for the clinician who asked for the scan. AI sits beside that pair of roles: it can sort, flag and review, but the report still goes through a person.

What AI medical imaging means

Start with the pictures. An X-ray is a quick test that uses a small dose of radiation to show dense parts of the body, such as bones, and the chest. A CT scan, short for computed tomography, uses X-rays and a computer to build cross-sectional pictures, often called slices. An MRI scan, short for magnetic resonance imaging, uses a strong magnet and radio waves, not X-rays. Ultrasound uses sound waves and a handheld device to show organs and soft parts of the body.

No single scan suits every case. A clinician asks for a scan, a radiographer takes it, and a radiologist reads it. AI enters at defined points in that chain.

AI here is machine learning: software trained on many past examples so it can spot patterns in a new image. In chest X-ray work, it has been trained to review the image and point to a possible abnormality, a part that looks different from the norm and may need a closer look. Nottingham University Hospitals NHS Trust explains in its LungIMPACT pages that AI is an extra screening tool, and it may lead to a further test, such as a CT scan, being done sooner.

The software does not look at a patient. It looks at pixels, the small dots that make up a digital image, and compares them with patterns met during training. A flag is a prompt for a person to look again, not a verdict.

Close-up view of a modern CT scanner in a healthcare facility.
A modern CT scanner, close up.

Three jobs AI does around a scan

The first job is sorting. When many scans arrive in a day, an AI tool can place the ones that look most urgent at the top of the list, so a specialist reviews them first. Bradford Teaching Hospitals NHS Foundation Trust describes this for chest X-rays: its AI support acts as a digital safety net, scanning images for subtle patterns beside its experts and flagging urgent cases for a specialist at once.

The second job is a second check. After a radiologist has read a scan, or alongside that reading, the software re-reads the same image and points to anything it thinks may have been missed. Nottingham's LungIMPACT pages call the software a second pair of eyes that re-looks at the image for extra safety. Two independent passes, one human and one software, are less likely to miss the same detail than one pass alone.

The third job is choosing the scan. Before a scan happens, someone must decide which type of scan fits the referral note, the short note that explains why the scan was requested. That step, called protocolling, is normally done by hand. In NHS Highland, a small team built a two-step AI tool for MRI referrals: first it reads the referral note and decides the general area, such as brain, spine or heart, then it narrows that down to the exact type of scan needed. Every suggestion still required a check by a scanning radiographer before a patient was scanned.

These three jobs share one pattern: the software handles a repeatable, well-defined task, and a trained person stays in charge of the step that affects the patient. When you hear a broad claim about AI in health care, ask which job, at which step, with which human check.

What is happening in the NHS

The clearest large-scale example in England is chest X-rays. On 10 June 2026, the UK government announced £20 million to roll out AI-powered chest X-ray tools to every NHS trust in England by 2029. They were already in use in about half of England's trusts, and the government said they had helped more than 4 million patients receive a faster lung cancer diagnosis or an all-clear.

Early data in the same announcement put the change in plain terms: radiologists analysed scans in an average of 4 days, compared with 8 days for the most complex cases before. The government also said the NHS carries out more than 7 million chest X-rays each year, and faster analysis should help more patients begin treatment within 62 days of a GP referral, in line with cancer waiting-time standards.

The same package added £8.1 million, through the National Institute for Health and Care Research, to test six further AI and digital technologies at 12 NHS trusts and one GP partnership across England and Scotland. Those projects cover analysis of CT scans, electrocardiograms and X-rays, digital therapy, and finding the most urgent cases first, for heart failure, stroke, lung cancer, lung infections and tic disorders.

The announcement also carries a caution from the clinical side: the president of the Royal College of Radiologists said AI should support doctors by helping them work more effectively, rather than replacing expert judgement, and that radiologists will remain central to diagnosis, clinical decision-making and patient care.

How AI learns from past scans

An AI imaging tool is only as good as the examples it learned from. Training means showing the software many past scans, each labelled by experts, until it can recognise patterns on its own. Where examples are few, results fall away, and the Highland MRI project shows both sides in one small study.

The Highland team collected 7,275 MRI referrals to train its tool. For scan types with plenty of data, early accuracy was high: 100% for heart scans, 99.9% for biliary system scans, and 98.2% for liver scans. For brain scans it was 73.6%, and for spine scans 79.7%. When two radiographers independently chose brain and spine scan types, they agreed only 70% of the time, so the software performed at a similar level to staff on those harder choices. The team named data availability as its main hurdle.

Those numbers come from one early project, not a national test. They show a useful rule: ask what a tool was trained on, how many examples covered your kind of scan, and how it was tested on unseen cases.

Training data also raises a fairness question. If past scans come mainly from one group of people, the software may fit that group best and others less well. The World Health Organization, in guidance published in January 2024, warns that health AI tools may be trained on poor-quality or biased data, and may produce false, inaccurate, biased or incomplete statements. A careful rollout checks results across different groups of patients, not just overall.

Where it still falls short

The first limit is accuracy on unusual cases. A scan that looks different from training examples, because of a rare condition or a fault in the image, is most likely to be misread. A second check helps, but it does not remove the risk. That is why Bradford states that every image is still personally reviewed and signed off by a qualified professional, and why Nottingham says patients in its study receive the usual care pathway.

The second limit is automation bias, a term the World Health Organization uses for a real habit: when software gives an answer, people may accept it without the same close look they would give their own reading. The defence is to keep the human reading independent, and to record cases where software and person disagree.

The third limit is privacy and security. The World Health Organization notes that health AI tools face cybersecurity risks that could endanger patient information, and its guidance asks governments to set standards and require independent post-release auditing when a tool is used at large scale. For a patient, the question is simple: who holds the scan data, and how long is it kept?

The fourth limit is evidence. A tool that works in a trial may not work the same way in daily use, where scanners differ and referral notes vary. Both the government announcement and the Highland project call their figures early data. Look for results from routine use, published and open to scrutiny, before treating a pilot result as settled fact.

Medical imaging setup with MRI scans on multiple screens in a healthcare facility.
MRI scans on multiple screens.

Frequently asked questions

Does AI read my scan instead of a doctor?

No, in the examples in this article. The software reviews the image and flags patterns for a trained person, and a radiologist still reviews and signs off the result. Nottingham's study pages say patients receive the usual care pathway, and Bradford states that every image is still personally reviewed by a qualified professional.

Will AI make my scan result come back faster?

It can shorten the wait in some settings, but it does not promise a faster result for any one person. In England, early government data put average analysis for chest X-rays at 4 days, against 8 days for the most complex cases before. Your own wait still depends on the clinic, the scan type, and what further tests are needed.

Can AI get a scan wrong?

Yes. It can miss a detail, flag something that turns out to be nothing, or perform less well on scan types with few training examples. The World Health Organization warns that health AI tools may produce false, inaccurate, biased or incomplete statements, and that staff may accept a software answer too readily. That is why the human check matters more than the software on its own.

AI medical imaging is best understood as help around a scan, not as a new kind of scan. It sorts urgent cases first, gives a second check, and helps choose the right type of scan, while a trained person still reads and signs off the result. The strongest evidence so far comes from narrow, well-tested jobs like chest X-ray review.

Start with the question the tool is meant to answer, check what it was trained on, and keep a person in charge of the final report.

If you would like help turning a clear process into a simple system, explore our services or get in touch through our contact page.

This article is for general information and is not medical advice. Please speak to a qualified healthcare professional about your own situation.

What to watch next

Update this article when the NHS chest X-ray rollout reaches new trusts, when the six NIHR projects report results, or when the World Health Organization updates its AI guidance. Then update the figures and Sources together.

Sources

  1. GOV.UK — AI to speed up cancer diagnosis for millions of NHS patients — date checked: 2026-11-01 — https://www.gov.uk/government/news/ai-to-speed-up-cancer-diagnosis-for-millions-of-nhs-patients
  2. World Health Organization — WHO releases AI ethics and governance guidance for large multi-modal models — date checked: 2026-11-01 — https://www.who.int/news/item/18-01-2024-who-releases-ai-ethics-and-governance-guidance-for-large-multi-modal-models
  3. Bradford Teaching Hospitals NHS Foundation Trust — Radiology and Imaging (Diagnostic Imaging Services) — date checked: 2026-11-01 — https://www.bradfordhospitals.nhs.uk/radiology-and-imaging/
  4. Nottingham University Hospitals NHS Trust — LungIMPACT FAQs — date checked: 2026-11-01 — https://www.nuh.nhs.uk/lungimpact-faqs/
  5. NHS Highland — Using Artificial Intelligence to speed up MRI scans in NHS Highland — date checked: 2026-11-01 — https://www.nhshighland.scot.nhs.uk/about/nhs-highland-charity/how-we-make-a-difference/using-artificial-intelligence-to-speed-up-mri-scans-in-nhs-highland/
  6. Hospital Healthcare — Chest X-ray AI tool deployed across NHS to accelerate lung cancer diagnosis — date checked: 2026-11-01 — https://hospitalhealthcare.com/specialisms/oncology/chest-x-ray-ai-tool-deployed-across-nhs-to-accelerate-lung-cancer-diagnosis/
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