Calcium mass in human aortas from autopsy

We used a single-energy x-ray method and an image processing system to measure the amount of calcium salts deposited in 60 human aortas (41 male and 19 female) of ages 15-88 y. The aortas were removed at autopsy, slit lengthwise and preserved in formalin. The aortas were x-rayed while flat, together with a calibration block containing known amounts of CaHPO4. We determined the amount of calcium salt, referenced to CaHPO4, from the x-ray film with a personal computer using a frame-grabbing board. There was less calcium in the thoracic than the abdominal aorta both in males and females and those of ages less than 50 y. The coefficient of correlation for abdominal aortic calcium mass versus age in 19 females was 0.557 and in 41 males was 0.321. The higher correlation of mass with age for females may be related to differences in calcium metabolism between sexes.