Observer Performance Studies

Clinical Assessment of Dry Laser-Processed Film vs. Traditional Wet-Processed Film

The goal of this study was to compare image quality and diagnostic performance (using ROC techniques) for laser imaging film from 2 systems : a traditional wet laser system that uses chemical processing and a new dry system (DryView Laser Imaging System) from Imation Corp. (formerly 3M Medical Imaging) that is wet-chemistry free.[7].

Methods

3 independent studies were performed : CT, MRI, US Each study used the same general methods.

Images

  • CT Study
  • 20 chest cases with subtle lung neoplasm's
  • 20 lesion free chest cases
  • MRI study
  • 20 cervical spine studies with subtle disk damage
  • 20 normal cervical spine cases
  • US study
  • 20 abdominal scans with subtle gallstones
  • 20 normal abdominal scans

Display

Images were printed to film once using traditional wet processing and once using the new DryView system from Imation (formerly 3M Medical Imaging Systems).   For more information on the DryView process, Link to the Imation webpage Separate studies were done for CT, MRI and US All cases were viewed on a standard view-box using a randomized presentation order.

Procedure

10 radiologists participated in each study Read each image twice (once on traditional wetfilm, once on the DryView film).  Reported diagnostic decision & gave confidence using a 6-level scale Subjectively rated the quality of films as poor, fair, good or excellent

Results

ROC Performance Analysis

  CT   MRI   US  
  Wet Dry Wet Dry Wet Dry
Mean AZ .831 .864 .860 .871 .868 .875
SE .04 .03 .02 .02 .02 .03
Range .712-.912 .782-.912 .767-971 .767-.921 .788-.951 .793-.971
AZ Diff -.033   -.011   -.007  
95% Limits -110, -.045   -070,-048   -065,.050  
F .7255   .1488   .0658  
df 1,351   1.351   1,351  
p .3996   .7018   .7990  

Image Quality

  • CT: sharpness & color were rated significantly higher for DryView than wet film
  • MRI: color was rated as significantly higher for DryView than wet film
  • US: overall quality, structure visibility, sharpness & contrast were rated significantly higher for DryView than wet film

Conclusions

  • Dry laser processing with Imation's DryView system produces high-quality radiologic films that are comparable to those currently produced nusing wet laser processing
  • Diagnostic accuracy did not differ between DryView film and wet film for CT, MRI & US images
  • DryView was rated equivalent to or better than wet film on overall quality, structure visibility, sharpness, contrast and color

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