AUTOMATIC FETAL HEAD MEASUREMENTS FROM SONOGRAPHIC IMAGES

Rationale and Objectives. We designed an image processing technique to automatically measure the biparietal diameter (BPD) and head circumfe rence (HC) from prenatal sonograms, We evaluated the performance of th e algorithm by comparing the resulting measurements with those made by experienced sonographers. Methods. Thirty-five digitized sonograms of the fetal head were obtained during routine imaging, The BPD and HC w ere automatically computed by detecting the inner and outer boundaries of the fetal skull using the computer vision technique known as the ' 'active contour model.'' Six experienced sonographers also measured th e BPD and HC on these images. Results. The algorithm failed to locate the boundaries in two of the 35 cases. For the remaining cases, the me an absolute difference betnieen the automated measurements and the ave rage of the six observers was 1.4% for BPD and 2.9% for HC. The correl ations were .999 for the BPD and .994 for the HC. The computer's measu rements were no different from the six observers' measurements than th e observers' measurements were from one another. Conclusion. The teste d algorithm effectively and accurately measures BPD and HC automatical ly. We are currently in the process of integrating this algorithm into an ultrasound machine.