Age-Related Structural and Metabolic Changes in the Pelvic Reproductive End Organs David Well, MSE, 1 Hua Yang, MD, 1 Mohamed Houseni, MD, Sireesha Iruvuri, MD, Saad Alzeair, MD, Maddalena Sansovini, MD, Nancy Wintering, MSW, Abass Alavi, MD, and Drew A. Torigian, MD, MA In this work, we provide preliminary data and a review of the literature regarding normal structural and functional changes that occur in the aging uterus, ovary, testicle, and prostate gland. It is expected that such knowledge will help physicians to distinguish physiologic changes from pathologic changes at an early stage. We retrospectively re- viewed pelvic magnetic resonance imaging (MRI) scans of 131 female and 79 male subjects ages 13 to 86 years to determine changes in volume of the uterus, ovary, and prostate gland with age. Scrotal ultrasound examinations of 150 male subjects ages 0 to 96 years also were analyzed retrospectively to determine changes in testicular volume with age. In addition, 18 F-fluorodeoxyglucose positron emission tomography ( 18 F-FDG-PET) scans of 145 male subjects ages 11 to 90 years were analyzed retrospectively to assess for changes in maximum standardized uptake value (SUV max ) of the testicles with age. The uterus had a mean volume of 38.55  3.68 cm 3 at 17 to 19 years of age, increased to a peak volume of 71.76  19.81 cm 3 between 35 to 40 years, and then declined to 24.02  8.11 cm 3 by the eighth decade of life. The maximal ovarian volume per subject maintained a relatively stable size in early life, measuring 9.46  3.25 cm 3 during the second decade of life, 8.46  3.32 cm 3 in the mid-fourth decade of life, and 7.46  3.33 cm 3 at 45 years of age, after which it declined to 4.44  2.02 cm 3 by the late fifth decade of life. The ovaries were not identifiable on MRI in subjects beyond the sixth decade of life. The volume of the prostate increased from 23.45  6.20 cm 3 during the second decade of life to 47.5  41.59 cm 3 by the late eighth decade of life; the central gland of the prostate increased from 9.96  3.99 cm 3 to 29.49  28.88 cm 3 during the same age range. Mean testicular volume was 11.2  5.9 cm 3 . Testicular volume increased with age from birth to 25 years. After age 25, there was a significant decline in the testicular volume. The mean SUV max for the testicles was 1.9  0.5. Testicular metabolic activity demonstrated an increasing trend until the age of 35 years. A plateau in SUV max was observed after the age of 35 years until the age of 65 years. A slight decrease in SUV max was observed after the age of 65 years. The pelvic structures of men and women change both structurally and functionally over the lifespan, and such changes can be quantified using ultrasound, MRI, and 18 F-FDG-PET. Semin Nucl Med 37:173-184 © 2007 Elsevier Inc. All rights reserved. M any studies have reported the physiological and hor- monal changes of the male and female reproductive organs with age. 1-7 It is important to supplement this knowl- edge with a description of how the appearances of these organs change over the lifespan using both structural and functional imaging techniques. With this knowledge, nuclear medicine physicians and radiologists will be better able to differentiate early pathology from changes of normal aging. In addition, geriatricians may gain a better understanding of the aging process in these organs and be better able to care for our aging population. To this end, we provide quantitative preliminary data of the age-related changes in volume of the uterus, ovary, prostate gland, and testicle based on retrospec- tive analysis of pelvic magnetic resonance imaging (MRI) or testicular ultrasonography (US) examinations, and changes in testicular metabolism with age based on 18 F-fluorodeoxy- glucose ( 18 F-FDG) positron emission tomography (PET). We Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA. 1 D.W. and H.Y. contributed equally to this work (co-lead authors). Address reprint requests to Drew A. Torigian, MD, MA, Department of Radiol- ogy, Hospital of the University of Pennsylvania, 3400 Spruce Street, Phila- delphia, PA 19104-4283. E-mail: Drew.Torigian@uphs.upenn.edu 173 0001-2998/07/$-see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1053/j.semnuclmed.2007.01.004