Comparison of the ultra-low-dose Veo algorithm with the gold standard filtered back projection for detecting pulmonary asbestos-related conditions: a clinical observational study

Our plain-English summary of Comparison of the ultra-low-dose Veo algorithm with the gold standard filtered back projection for detecting pulmonary asbestos-related conditions: a clinical observational study, by M. Tekath, F. Dutheil, R. Bellini, et al (BMJ Open, 2014).

The study

• Authors: M. Tekath, F. Dutheil, R. Bellini, A. Roche, B. Pereira, G. Naughton, A. Chamoux, J.L. Michel
• Journal: BMJ Open
• Published: 2014;4(5):e004980
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objectives: Radiation delivered during CT is a major concern, especially for individuals undergoing repeated screening. We aimed to compare a new ultra-low-dose algorithm called Veo with the gold standard filtered back projection (FBP) for detecting pulmonary asbestos-related conditions.

Setting: University Hospital CHU G. Montpied, Clermont-Ferrand, France

Participants: Asbestos-exposed workers were recruited following referral to screening for asbestos-related conditions. Two acquisitions were performed on a 64-slice CT: the gold standard FBP followed by Veo reconstruction.

Outcome Measures: Two radiologists independently assessed asbestos-related abnormalities, pulmonary nodules, radiation doses and image quality (noise).

Results: We included 27 asbestos-exposed workers (63.3±6.5 years with 11.9±9.7 years of asbestos exposure). We observed 297 pleural plaques in 20 participants (74%). All patients (100%) had pulmonary nodules, totalling 167 nodules. Detection rates did not differ for pleural plaques (Veo 87% vs FBP 97%, NS), pleural thickening (100% for both) and pulmonary nodules (80% for both). Interstitial abnormalities were depicted less frequently with Veo than FBP. False negative and false positive did not exceed 2.7%. Compared with FBP, Veo decreased the radiation dose up to 87% (Veo 0.23±0.07 vs FBP 1.83±0.88 mSv, p<0.001). The objective image noise also decreased with Veo as much as 23% and signal-to-noise ratio increased up to 33%.

Conclusions: A low-dose CT with Veo reconstruction substantially reduced radiation. Veo compared favourably with FBP in detecting pleural plaques, pleural thickening and pulmonary nodules. These results should be confirmed on a larger sample size before the use of Veo in clinical routine practice in asbestos-related conditions, especially regarding the low prevalence of interstitial abnormalities in this study.

Trial Registration Number: NCT01955018.

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In plain English

This study, at the University Hospital in Clermont-Ferrand, France, compared two chest CT methods in 27 asbestos-exposed workers referred between September 2012 and April 2013. Each worker had a standard-dose scan processed with the usual method (filtered back projection, FBP) and an ultra-low-dose scan processed with a newer method called Veo. Two radiologists read the images. Veo gave an average effective dose of 0.234 mSv against 1.825 mSv for FBP, an 87.2% reduction. Of 297 pleural plaques found in 20 workers (74%), Veo detected 259 (87%) and FBP 287 (97%). This difference was not statistically significant (p=0.10). Both methods detected diffuse pleural thickening in all four workers who had it. Of 167 lung nodules, Veo found 134 and FBP 133 (80% each). Veo picked up the non-specific interstitial lung changes seen in 15 workers less often. No true asbestosis was recorded. The authors concluded that Veo substantially reduced radiation and compared favourably with FBP for plaques, thickening and nodules. They said a larger study is needed before routine use, especially for interstitial abnormalities.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Clinical observational study comparing two CT acquisitions (standard-dose with filtered back projection and ultra-low-dose with Veo reconstruction) performed on the same patients and read by two radiologists
• Who was studied: 27 asbestos-exposed workers analysed out of 87 referred and 29 who consented. They were referred by the occupational medicine department to the radiology department of University Hospital CHU G. Montpied, Clermont-Ferrand, France, between September 2012 and April 2013. Mean age was 63.3 years (standard deviation 6.5). Excluded were people with a history of cancer or thoracic surgery, or other known interstitial disease.
• Exposure: Past occupational asbestos exposure, mean duration 11.9 years (standard deviation 9.7). Fiber types and jobs were not specified. The comparison studied was standard-dose CT with FBP reconstruction versus ultra-low-dose CT with Veo reconstruction.
• Main results:
  • Average effective radiation dose was 0.234 mSv for Veo and 1.825 mSv for FBP, a dose reduction of 87.2% (p less than 0.001)
  • 297 pleural plaques were seen in 20 participants (74%). Veo detected 259 (87%) and FBP 287 (97%), p=0.10, a difference that was not statistically significant.
  • For plaques, Veo produced three false positives (intercostal fat or muscles) and eight false negatives (2.7%)
  • Looking only at whether each patient had any pleural plaque, agreement between Veo and FBP was 96% (kappa 0.91). Agreement plaque by plaque was 84% (kappa 0.05).
  • Diffuse pleural thickening was present in 4 patients (14.8%) and was detected in all of them by both techniques (kappa 1). No pleural effusion was found.
  • All patients had pulmonary nodules, 167 in total, all smaller than 10 mm. Veo detected 134 of 167 and FBP 133 of 167 (80% each, p=0.98). Veo had 7 false positives (4%) and 4 false negatives (2.7%).
  • Parenchymal (interstitial) changes were found in 15 participants (55.6%). For these, Veo's overall sensitivity was 46.7% (95% CI 21.3 to 73.4) and specificity 100%. No honeycombing and no true asbestosis was recorded.
  • Veo reduced measured (objective) image noise by 13% to 23% and increased signal-to-noise ratio by 5% to 33%. However, both readers rated subjective image noise higher with Veo in most views.
  • Agreement between the two radiologists was low for pleural plaque detection (0.09 for FBP, 0.10 for Veo) and fair for nodule detection (0.34 for both)
• The authors' conclusion: The authors concluded that low-dose CT with Veo substantially reduces radiation and compared favourably with FBP in detecting pleural plaques, diffuse pleural thickening and pulmonary nodules. They said the results should be confirmed in a larger sample before routine clinical use, especially because interstitial abnormalities were rare in this study. In the discussion they said that, because of its false positives and false negatives, Veo should not be used for a first examination but seems possible for follow-up.
• Limitations the authors state:
  • Small sample size, which also increased the need for the radiologists to adapt quickly to unfamiliar Veo images
  • Interstitial abnormalities were rare, preventing sound statistical analysis. They were likely underestimated because recording was not detailed enough.
  • Veo was always performed after FBP, which may have increased gravity-dependent attenuation in the back of the lungs and masked abnormalities. Scans were done lying face up, and prone views were not always performed, so the posterior region was not analysed with confidence.
  • Iterative reconstruction such as Veo currently requires long computing time

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Pleural Plaques, Pleural Thickening, Interstitial.

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