Image preparation

A.Prof Frank Gaillard et al.

Images are clearly a very important part of Radiopaedia.org and we aim for high quality and uniformity across the site. As always patient anonymity is essential, and any images with patient details included will be removed, and cases usually deleted.

Radiology is all about image quality and as such it is crucial for the site as a whole and for your online contributions to be of high quality. We are not all blessed with state-of-the-art hardware, but that is no excuse for poorly optimized images. 

Before uploading an image please ensure that: 

  1. the images have appropriate window/level/contrast/brightness
  2. are of sufficient resolution (see below)
  3. are appropriate for teaching (slice thickness, views etc..) 
  • JPG: small size but degraded by compression; use quality of 80 or above to minimise image degradation
  • PNG: non-lossy, reasonable size, the preferred format for diagrams, as edges and text will be crisp

Radiopaedia.org accepts (essentially) any size and then resizes it to serve up to viewers. Thus uploading a larger size. Although Radiopaedia resizes small images (e.g. from MRI) generally uploading larger images resized by your PACS is safer and results in a better image. 

Never (except for plain films and mammography) upload images that are smaller than the size aquired: 

  • CT: 512 x 512 pixels (px)
  • MRI: sequence-specific ranging from 128 to 1024 px
  • x-ray: variable ~ 1600 x 1600 px
  • ultrasound: 512 x 512 px
  • mammography: 2048 x 2048 px
  • angiography (DSA): 1600 x 1600 px

If in doubt upload a larger image. We keep all the original images and optimize the images for display on bowsers. 

Please keep images close to a square aspect ratio. It makes sure that the thumbnails and displayed images are relatively uniform.

If your image is tall and thin (e.g. limb x-ray) then add black space around the sides to make the image square. This adds very little to the overall size of the image and makes it look great. 

In general please have only one image/slice/projection per image. This is especially the case for cross-sectional imaging.

The one exception (sometimes)  is long/thin x-rays (e.g. limbs) which can be better presented as side by side views.

For cross-sectional images (CT and MRI) or temporal sequences (DSA run), sequential images can be uploaded as a single .zip file containing sequentially numbered images (see example 3). See stacks for more information.

Important: NEVER upload every single thin image you have. A 650 x 0.6 mm stack is useless. 

Taking photos of printed film is tricky, and genreally discouraged. Some historical films are worth preserving and with a little practice, reasonable results can be obtained.

  • camera settings
    • black/white (you can convert to greyscale later too)
    • macro
    • high-quality jpg (90 or 100)
      • you can convert .raw or .tiff image types to png but this is of limited utility as JPG image degradation is not the quality limiting step
  • tripod ideal
  • glare from next to the film is horrible so need to mask it out
    • for CT/MR which are the standard size a hole cut in card works fine
    • for odd shapes need to be more inventive
  • reflections may not be apparent until you look at the image, so a pitch black room except for the lightbox is best, and even then you may see a reflection of yourself
  • autofocus often does not work (fluffy images) so focusing on a sheet of paper with lines drawn on it placed in front of the film works well; alternatively set your focus to the central dot, and aim initially at the patient demographics (remember to exclude these or edit them out later)
  • it can be really hard to replicate a nice flat image when there is dense bone (when the film is completely transparent you get a lot of glare and can't see the rest; see example 4)

A number of tools are useful to make sure your images are the best they can be (for Radiopaedia.org and for publication).

  • Seashore
    • lightweight GIMP (see below)
    • does everything you need it to, fast and easy
    • Mac only
    • http://seashore.sourceforge.net/
  • Photoshop
    • not-free... not even close
    • the 'gold standard' of photo editing software
    • (Windows and Mac)
  • Gimp
    • free
    • opensource alternative to photoshop
    • www.gimp.org/ (Windows, Linux and Mac) 
  • Irfan viewer
    • free
    • powerful image converted (great for batch processing images)
    • http://www.irfanview.com/  (Windows only)

If you do not want to install software on the computer you are using you can use online browser-based programs of which there are dozens.

  • Phixr.com
    • free
    • lets you crop and convert to grey scale
    • http://www.phixr.com
  • Pixlr.com
    • free,
    • lets you crop and annotate
    • https://pixlr.com/
  • Windows right click - add to archive
  • Mac right (secondary) click - compress to archive
  • 7zip - www.7-zip.org/ - powerful open source easy to use archive utility (Windows, Linux and Mac)
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rID: 6646
Tag: help
Synonyms or Alternate Spellings:
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