Radiology · Interventional radiology
Medical imaging, made visual.
Short animated lessons on radiology, interventional radiology and imaging for every specialty.
- 5 free lessons
- English and Turkish
- Real, openly licensed images
Can you spot it?
Tap where this head CT looks different.
Unenhanced head CT. Compare the two sides, then tap the area that looks abnormal.
What Contrast is
Real scans, live contours
Every lesson is built on real, openly licensed scans, with the finding outlined in gold as you watch.
Animated lessons & IR procedures
Signs, artefacts and imaging physics, and interventional procedures step by step, in a minute or less.
Spot it: learn by playing
Find the finding before the answer. Short image puzzles that train your eye.
The Contrast app
Signs atlas, image cases, IR devices in 3D, procedure simulations and mock exams, in English and Turkish.
Latest lessons
All lessons →
CT windows: one scan, many pictures
Why the same CT slice can look completely different: Hounsfield units, the limited greys of a screen, and why scans are read in more than one window.
Early ischaemic signs on unenhanced CT
The subtle signs of an early middle cerebral artery infarct on a plain head CT: the insular ribbon, the lentiform nucleus and the grey-white border.
Pulmonary embolism on CT: the filling defect
How a pulmonary embolus looks on CT pulmonary angiography, how acute and chronic clot differ, and why a poor study should say what it could not assess.
Finding of the week
CT windows: one scan, many pictures
Check yourself
On the Hounsfield scale, what value is water?
Why Contrast
In radiology a good image often says more than a long paragraph. Yet images that are openly licensed, tied to primary sources and explained in more than one language are hard to find in one place.
Contrast brings them together. Every lesson starts with a real image, every number goes back to a primary source, and the Turkish text is written in the language Turkish radiologists actually use.
— The founder of Contrast
Be first to try Contrast
Join the waitlist: we will e-mail you when the app opens, plus a short newsletter with new lessons. Unsubscribe any time.
Questions
Who is Contrast for?
Medical students, radiology and interventional radiology residents, radiographers, and doctors in every specialty who read or order imaging.
Does it cost anything?
The lessons on this site are free. The app is free during its beta; pricing after that has not been decided yet.
Which languages?
English and Turkish. Every lesson is written in both.
Do I need an account?
No. The site has no accounts, and the app beta works without one: your progress stays on your own device.
Can I use it offline?
In the app, lesson packs can be downloaded to your device and opened without an internet connection.
Where do the images come from?
From de-identified public datasets and open-access publications, under open licences such as CC0, CC BY and CC BY-SA. The source and licence are written under every image.
Is this medical advice?
No. Contrast is for education only and does not replace clinical judgement or local guidelines.
When does the app open?
There is no date yet. People on the waitlist hear first.
Follow along
One finding a week on YouTube, Instagram, TikTok and X.