Development of the pineal gland: measurement with MR.

PURPOSE To use MR imaging in the analysis of the size of the normal pineal gland in infants, children, and adolescents. METHODS We retrospectively analyzed the size of the pineal gland in 249 patients (129 male and 120 female) aged 2 weeks to 20 years old. The maximum length (L), height (H), and width (W) of the gland were determined from a combination of sagittal, coronal, and axial MR images obtained on a 1.5-T scanner. The volume was calculated by using the formula 1/2 x L x H x W. RESULTS The size of the pineal gland was significantly smaller in patients younger than 2 years old than in older patients. The size of the pineal gland increased until 2 years of age and remained stationary between the ages of 2 and 20 years. We found a large variation in size among all age groups. No difference in size was noted between males and females. CONCLUSION This study establishes norms for pineal gland size in infants younger than 2 years old and in children and adolescents 2 to 20 years old as detected with MR imaging. Knowledge of the size of the normal pineal gland is important in the detection of abnormalities of the pineal gland, particularly neoplasms.