Incidental Findings and Low-Value Care

A whopping 15% to 30% of diagnostic imaging exams reveal at least one incidental finding. Each of those findings might seem like blessings to radiology outsiders, but a popular new AJR editorial argues that imaging incidentals are far more likely to drive low-value care.

Michigan Medicine’s Matthew Davenport, MD led-off his editorial by suggesting that early cancer detection “is not always an ideal outcome,” because most of those cancers won’t affect patient health, while incidental follow-ups always require resources and often negatively impact patients (physically, financially, and emotionally).

He identified numerous reasons for radiology’s incidental overdiagnosis challenges…

  • Screening low-risk patients inherently uncovers low-risk incidentals
  • There’s a lack of understanding of incidental risks (clinically and downstream)
  • Many early cancers don’t or shouldn’t require treatment
  • Radiologists face significant pressure to recommend follow-ups

Although many incidental findings significantly improve patient outcomes, and those positive examples have established incidentals as a “secondary benefit of imaging,” the editorial suggests that incidentals will have a negative overall impact on radiology’s value until current practices change. 

So, what should we do? Dr. Davenport encourages radiologists to…

  • Become more aware of the harms of incidental management
  • Advocate for guidelines that emphasize high-value care
  • Support research on incidental management practices
  • “Avoid being alarmist” about incidentals in radiology reporting
  • Adopt solutions to help rads assess incidental patients’ risk factors
  • Balance diagnostic sensitivity with minimizing follow-up risks 

The Takeaway

If you scroll through the Imaging Wire archives, you’ll find plenty of stories that depict incidentals as a net positive for patient care. In fact, most suggest that radiology’s research and business leaders are actively trying to find ways to detect more incidentals. However, efforts to better understand or to reduce incidentals’ negative impacts are far less common. 

That divide is pretty notable given how many radiologists agree with Dr. Davenport, and it suggests that the barriers to solving incidental findings’ value problems are quite high.

Incidental Evolution

Last week brought a wave of studies that either highlighted how findings in common imaging exams could add value in completely different clinical areas, or showed how incidentals could find a home in established clinical workflows. That might not be welcomed news among the many radiologists who view incidentals as a clinical slippery slope, but it’s another sign that the incidental evolution is gaining momentum.

Left Atrial Dementia Marker – A new JAMA study showed that echocardiographic left atrial function measurements can be used to identify individuals with higher dementia risks, in addition to supporting cardiovascular diagnosis. Analysis of 4,096 participants’ echo exams and 6-year outcomes (75yr avg. age; 531 developed dementia) revealed that lower left atrial function (e.g. reservoir strain, conduit strain, contractile strain, active emptying fraction, emptying fraction) has a statistically significant association with developing dementia (1.43 to 1.98 hazard ratios).

BACs and CVD – A Kaiser Permanente study added more evidence supporting breast arterial calcifications’ value as a cardiovascular disease risk factor. The researchers analyzed 5,059 women’s digital mammography exams (26.5% w/ BACs), finding that women with BACs had a 51% higher risk of developing atherosclerotic CVD and a 23% higher risk of developing any type of CVD over 6.5-years. This is far from the first study to tie BACs to CVD risk, but it came with a high level of credibility (large/observational study, published on Circulation) and generated quite a bit of media attention.

Auto CAC Pathway – A Journal of Digital Imaging study highlighted how coronary artery calcium scores (CAC scores) could be integrated into standard cardiovascular disease (CVD) risk systems, potentially streamlining CAC AI adoption. The researchers used an FDA-cleared AI model (believed to be from Nanox AI) to screen 14,135 patients’ existing CTs (470 who experienced CVD within 5yrs) and then combined their CAC scores with the ACC/AHA’s PCE risk system. The AI-augmented PCE predictions outperformed standard PCE predictions (sensitivity: 57% vs. 53%; specificity: 70% vs. 67%), without requiring additional scans or diagnostic workflows.

Northwestern Follows-Up – A new NEJM study highlighted the impressive results of Northwestern Medicine’s lung nodule follow-up system, which uses NLP to identify suspicious nodules and then initiates a follow-up workflow (prompts physicians, notifies patients, tracks follow-ups). Over 13 months, the system screened over 570k imaging studies, flagging 29k exams for follow-up (77.1% sensitivity, 99.5% specificity, 90.3% PPV), and tracked over 2,400 follow-ups to completion.

The Takeaway
Last week’s batch of studies serve as yet another reminder that common imaging exams could serve broader clinical roles the future, either by creating new risk-based incidental pathways (LA function for dementia; BAC for CVD), catching more undetected incidentals (AI CAC scoring), or by formalizing how incidentals are brought into clinical pathways (e.g. adding CAC to PCEs; leveraging NLP for follow-ups).

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