The effects of the conversion and enlargement of digital radiological image from DICOM to JPEG image format on distance measurement
- Published
- Accepted
- Subject Areas
- Anatomy and Physiology, Evidence Based Medicine, Radiology and Medical Imaging
- Keywords
- image conversion, JPEG, DICOM, measuring distance, human diaphragm
- Copyright
- © 2015 Mihanović et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
- Cite this article
- 2015. The effects of the conversion and enlargement of digital radiological image from DICOM to JPEG image format on distance measurement. PeerJ PrePrints 3:e1383v1 https://doi.org/10.7287/peerj.preprints.1383v1
Abstract
Introduction. Conversion of images from DICOM format to other image formats affects measuring distances in images. Materials and methods. Distances in DICOM or JPEG images were measured with different zoom using 1.5T MRI scanning of human diaphragm during spontaneous breathing and during low and high lung volumes. Results. Correlation between distance measurements in mm and pixels at all zoom factors on DICOM and JPEG images ranged from r=0.9981-1.00 and 95% CI for r of 0.9972 - 0.9986 to 1.00 - 1.00 and the p-value in all correlations was <0.001. Results of comparing the difference in measured dimensions on DICOM and JPEG images in mm for F1.0 indicate that differences in measurements are small (0.1 mm average). Image zooming in JPEG for F1.8 compared to the idealized pixel size values with that zoom on average increases the number of pixels for 1 (range from 5 pixels increase to 4 pixels loss). Conclusions. The values of linear regression equation for all zoom factors (F1.0 - F1.8) indicate that distance measurement on the zoomed JPEG image is not suitable for obtaining accurate results of distance measurements. The distance measurements in JPEG images without zoom are entirely in accordance with distance measurements in DICOM images. In the zoomed images distance measurements differ from the results of distance measurements in DICOM format and for the possible use of the results it is necessary to provide data on zoom factor, physical size of the pixel spacing and the values of the linear regression equation.
Author Comment
The aim of this study was to investigate the effects of the conversion and enlargement of digital radiological image from DICOM to JPEG image format on distance measurement. The results suggest that conversion of images from DICOM to JPEG image file format for distance measuring can be selectively used depending on clinical case, physiological and pathological changes, the purpose of measurement and user’s assessment of the usefulness of measurements, for example in research. Measurements of distance in JPEG images without zoom are fully consistent with distance measurements in images in DICOM format. In zoomed images in JPEG format the distance measurement results differ from the results in DICOM format. Therefore, the data on zoom factor, the physical acquisition pixel size and values of linear regression equation are necessary in order to use the results of distance measurements in JPEG format.
