A Simple Method for Quantifying Blastema Growth in Regenerating Planarians: measure blastema area

Open the planarian image in ImageJ and reset scaling using the scale image from that day. Convert the image from RGB to 8-bit grayscale to create a black and white image suitable for analysis.

Apply contrast enhancement with a value of 0.15 to increase the distinction between the worm and background. Use the rectangle tool to carefully draw a region of interest around the blastema, ensuring complete coverage while minimizing background inclusion.

Duplicate the selected image region and apply threshold adjustment to the duplicate. Adjust the threshold slider so the blastema appears in red/color while the background turns black, maximizing blastema visibility.

Set measurement parameters to track only area. Use Analyze Particles with size range 0 to Infinity, enabling options for outlines display, results, hole inclusion, and overlay visualization.

Locate the blastema in the outlines image (labeled as particle number 4) and identify its area value (0.052 in this example) from the results table. Record this measurement in the workbook template.

Save both the outline and thresholded images to a designated results folder for future reference and documentation. Label files clearly with the specimen identifier (e.g., Title Nine outline, Title Nine threshold).