Measure Ulcer Area from a Photo

OsiriX and Horos Course · Measurements and Tools

In this video I show, at the request of Professor Eliud, how to assess an ulcer from a photograph using OsiriX (the same logic applies to Horos). The idea is to turn a photo (JPEG) into a calibrated image so you can measure area in cm² and track the wound's progress over time. 1) Enable JPEG import in OsiriX By default, OsiriX usually allows only DICOM. To import a photo: Go to Preferences Open Database Uncheck: Import only DICOM files ⚠️ Note: “JPEG” appears in several places in the preferences (including settings related to DICOM compression). The correct setting is in Database, in the option to import only DICOM files. 2) Import the photo Drag the photo into the database or use the import files option Double-click to open the image 3) Calibrate: tell OsiriX what 1 cm corresponds to Since the photo is not DICOM, OsiriX measures in pixels (e.g., 105 pixels). To convert to centimeters: Use the straight ruler (Length) and measure 1 cm on the photo's reference (a ruler) Right-click the measurement Select Recalibrate resolution Enter that this distance corresponds to 1 cm After that, all measurements come out in cm instead of pixels. (If needed, you can zoom in to calibrate more precisely and recalibrate again.) 4) Measure the ulcer area (cm²) You can measure area in several ways. In the video I show two: A) Closed Polygon Place points around the ulcer On the last point, double-click to close OsiriX returns the area (e.g., ~10 cm² in the example) B) Brush Adjust the brush size “Paint” the ulcer area Double-click to finish and get the area (e.g., ~9.7 cm² in the example) 5) What this is for With the same technique, you can assess several photos over time and compare whether the wound is improving or getting worse. 6) Calibration references (besides a ruler) If the photo has no ruler, you can calibrate using an object of known size, for example: a coin (knowing its diameter) a credit card (standard size) ⚠️ Be careful with syringes: the mL markings do not always correspond to centimeters — keep an identical syringe next to the wound to confirm the real measurement.