Tag: neuroradiology

Real-World Stroke AI Implementation

Posted on by Brian Casey

Time is brain. That simple saying encapsulates the urgency in diagnosing and treating stroke, when just a few hours can mean a huge difference in a patient’s recovery. A new study in Clinical Radiology shows the potential for Nicolab’s StrokeViewer AI software to improve stroke diagnosis, but also underscores the challenges of real-world AI implementation.

Early stroke research recommended that patients receive treatment – such as with mechanical thrombectomy – within 6-8 hours of stroke onset. 

  • CT is a favored modality to diagnose patients, and the time element is so crucial that some health networks have implemented mobile stroke units with ambulances outfitted with on-board CT scanners. 

AI is another technology that can help speed time to diagnosis. 

  • AI analysis of CT angiography scans can help identify cases of acute ischemic stroke missed by radiologists, in particular cases of large vessel occlusion, for which one study found a 20% miss rate. 

The U.K.’s National Health Service has been looking closely at AI to provide 24/7 LVO detection and improve accuracy in an era of workforce shortages.

  • StrokeView is a cloud-based AI solution that analyzes non-contrast CT, CT angiography, and CT perfusion scans and notifies clinicians when a suspected LVO is detected. Reports can be viewed via PACS or with a smartphone.  

In the study, NHS researchers shared their experiences with StrokeView, which included difficulties with its initial implementation but ultimately improved performance after tweaks to the software.  

  • For example, researchers encountered what they called “technical failures” in the first phase of implementation, mostly related to issues like different protocol names radiographers used for CTA scans that weren’t recognized by the software. 

Nicolab was notified of the issue, and the company performed training sessions with radiographers. A second implementation took place, and researchers found that across 125 suspected stroke cases  … 

  • Sensitivity was 93% in both phases of the study.
  • Specificity rose from the first to second implementation (91% to 94%).
  • The technical failure rate dropped (25% to 17%).
  • Only two cases of technical failure occurred in the last month of the study.

The Takeaway

The new study is a warts-and-all description of a real-world AI implementation. It shows the potential of AI to improve clinical care for a debilitating condition, but also that success may require additional work on the part of both clinicians and AI developers.

PET’s Milestone Moment

Posted on by Brian Casey

In a milestone moment for PET, CMS has ended its policy of only paying for PET scans of dementia patients if they are enrolled in a clinical trial. The move paves the way for broader use of PET for conditions like Alzheimer’s disease as new diagnostic and therapeutic agents become available. 

CMS said it was rescinding its coverage with evidence development (CED) requirement for PET payments within Medicare and Medicaid. 

  • Advocates for PET have chafed at the policy since it was established in 2013, claiming that it restricted use of PET to detect buildup of amyloid and tau in the brain – widely considered to be precursors to Alzheimer’s disease. The policy limits PET payments to one scan per lifetime for patients enrolled in clinical trials. 

But the landscape began changing with the arrival of new Alzheimer’s treatments like Leqembi, approved in January 2023. CMS telegraphed its changing position in July, when it announced a review of the CED policy, and followed through with the change on October 13. The new policy…

  • Eliminates the requirement that patients be enrolled in clinical trials
  • Ends the limit of one PET scan per Alzheimer’s patient per lifetime
  • Allows Medicare Administrative Contractors (MACs) to make coverage decisions on Alzheimer’s PET
  • Rejects requests to have the policy applied retroactively, such as to when Leqembi was approved

CMS specifically cited the introduction of new anti-amyloid treatments as one of the reasons behind its change in policy. 

  • The lifetime limit is “outdated” and “not clinically appropriate” given the need for PET for both patient selection and to potentially discontinue treatment if it’s ineffective or if it’s worked to clear amyloid from the brain – a key need for such expensive therapies. 

The news was quickly applauded by groups like SNMMI and MITA, which have long advocated for looser reimbursement rules.

The Takeaway

The CMS decision is great news for the PET community as well as for patients facing a diagnosis of Alzheimer’s disease. The question remains as to what sort of reimbursement rates providers will see from the various MACs around the US, and whether commercial payers will follow suit.

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