Age-dependent decrease in the computed tomographic numbers of parotid and submandibular salivary glands

The computed tomographic (CT) numbers of 182 normal parotid glands were measured in patients ranging in age from 1 to 81 years, and of 172 normal submandibular glands with an age range of 1-85 years. The mean CT number (+/- s.d.) of the parotid and the submandibular glands was -10 +/- 24 Hounsfield units (HU) and 41 +/- is HU respectively. Sex and intra-individual differences in the CT numbers were small, but significant linear decreases were found with age in both glands. The mean annual decrease was 0.5 HU.