In this study, we investigated quantitative evaluation of aortic calcification employing thoracic images scanned by helical CT.
To measure a volume of aortic calcification in a series of thoracic images, we developed a software on Apple Macintosh personal computer that extract calcification semiautomatically. The measurement process of calcification in this program consists of the following steps: (1)manual designation of an approximate center point in the aorta area on the first image, (2)semiautomatical extraction of aortic ROI by successive radial edge detection, (3) measurement of the sum of calcification pixels in the ROI and of the sum of scored calcification values that was weighted by the factors alloted to the CT numbers of the calcification pixels, and (4)calculation of the total sum of the number of the calcification pixels and the total sum of scored calcification values by applying(1)-(3) repeatedly to whole slice images of a patient.
We proccessed 10 series of thoracic helical CT images containing aortic calcification at an interval of 2 years.
In consequence, our evaluation method could quantitate the temporal change of amounts of aortic calcification.
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