The rubber circle: a technique for analyzing computed tomography scans

The authors describe a technique for automated analysis of lesions demonstrated by computed tomography. A seed circle may be superimposed on a lesion by an operator controlled program. By selecting density limits, the program will then automatically outline a particular area of abnormal density and calculate the statistics of the pixels within that area. The information may be viewed on the computer terminal or recorded on the printer. The system may be superimposed on first generation EMI scanners without additional hardware. The time for obtaining the information roughly approximates that of systems employing manually operated cursors.