Although the number of hard-copy films submitted for secondary neuroradiology interpretations have plummeted, the volume of non-DICOM CDs has nearly doubled, according to a study published in the April issue of American Journal of Roentgenology.

The transition from film-based to digital exam review sparks a number of administrative and planning questions: staffing needs, reading room remodel and size needs, light box or film changer capacity, number of PACS viewing stations and number of PCs to handle non-DICOM CD exams.

Christopher H. Hunt, MD, from the department of radiology at Mayo Clinic in Rochester, Minn., and colleagues sought to determine trends in the volume and format of outside neuroradiology studies submitted for secondary interpretation from Nov. 1, 2006 through Dec. 31, 2010.

A total of 52,169 individual cases were submitted for secondary interpretation during the course of the study, with no statistically significant change in overall volume during the four-year project.  

Hunt and colleagues reported that hard-copy exams dropped from a mean of 297 cases per month in 2007 to mean of 57 exams per month in 2010. The decline was matched by a concomitant increase in exams submitted by CD-ROM—from a mean of 753 cases per month in 2007, to 1,036 cases per month in 2010.

Most exams submitted via CD adhered to DICOM format, but the number of non-DICOM CDs nearly doubled from nine cases per month in 2007, to 17 cases per month in 2010, according to Hunt et al.

The trend of “persistent and increasing non-DICOM format examinations … is unexplained by a change in the overall volume of examinations,” they wrote.

The researchers outlined a number of problems associated with non-DICOM CDs. These are:

• The clinician often must rely on unique proprietary software and image manipulation tools to view the images.
• The format does not allow side-by-side comparisons within series of an exam or within two exams or modalities.
• Archiving can be difficult or impossible, creating complications for later image comparison and review.

Hunt et al also pointed out that the overall number of cases submitted for interpretation did not increase during the study, which seems to run counter to increasing pressure to limit repeat studies and the improved ability to share exams electronically.

They conjectured that the finding may be related to increasing reluctance or difficulty in patients obtaining outside films, increased costs to copy exams, reduced or eliminated reimbursement for reinterpretation of outside exams unless accompanied by a new exam and continued willingness by payors to cover repeat radiology studies.

The findings led Mayo Clinic to make a number of changes, including reducing the number of hard-copy film viewers and increasing DICOM-compatible display stations. The clinic also had to improve its ability to accommodate non-DICOM studies.

Hunt and colleagues urged the radiology community to continue to promote the DICOM standard, linking it with patient safety and noting that the DICOM header ties the patient to the image and eliminates the possibility of misinterpretation. The standard also better preserves image resolution and quality. Non-DICOM formatted exams require a separate viewing station, which means costs may increase.

Finally, non-DICOM data cannot be stored in the enterprise viewer or EMR. “This will become a problem nationally with the drive to implement EMRs, which will require standardization and, therefore, DICOM-compatible images for all specialties, including radiology.”