The effects of aging on testicular volume and glucose metabolism: an investigation with ultrasonography and FDG-PET.

OBJECTIVES: To investigate the effects of senescence on testicular volume and metabolism by quantitative analysis of volumetric and functional data provided by genital ultrasonography (US) and 2-deoxy-2-[(18)F]fluoro-D-glucose(-)positron emission tomography (FDG-PET), respectively. METHODS: Three hundred twenty (PET 173, US 147) male subjects (average age, 47.9 ± 24.1 years; range, 11-90 years) who previously underwent US or FDG-PET imaging were included in this retrospective study. Testicular volumes and FDG maximum standardized uptake values (SUV(max)) were correlated with age using polynomial regression and Pearson linear regression analysis. RESULTS: With cross-sectional analysis, the best-fit curves demonstrated statistically significant overall correlations between changes in both the volume and metabolism (SUV(max)) of the testicle and increasing age (volume: R(2) = 0.42, p = 0.0002; SUV(max): R(2) = 0.26, p < 0.0001). Testicular volume rapidly increases during puberty and peaks at age 30 years. Subsequently, the volume of the testes stabilizes in a plateau-like manner until age 60 years. After age 60 years, this study shows that testicular volume decreases significantly. Testicular glucose metabolism increases until age 40 years, after which it declines gradually over time at a constant rate. CONCLUSION: Testicular volume and metabolism appear to be significantly affected by advancing age at different rates during the different stages of lifespan. The rapid increase in testicular volume and metabolism parallel the onset and progression of puberty and positively correlate with increasing age up to ages 30-40 years. Between ages 40 and 60 years, testicular volume and metabolism remain relatively constant with only a minimal decline. After age of 60 years, the testicular volume significantly declines, while testicular metabolism progressively declines until age 90 years.

Assessment of age-related changes in abdominal organ structure and function with computed tomography and positron emission tomography.

With the size of the aged population in the United States expected to grow considerably during the next several decades, the number of imaging studies performed on such aged individuals will similarly increase. Thus, it is important to understand normal age-related changes in the structural and functional imaging appearance of the abdominal organs. We therefore present preliminary data and a review of the literature relevant to structural and functional changes in the abdominal organs of children and older adults. In a retrospective study of both adult and pediatric populations, we used computed tomography (CT), positron emission tomography (PET), and PET/CT imaging to investigate age-associated changes in size, attenuation, and metabolic function of the abdominal organs. Organs of interest include the liver, spleen, pancreas, kidneys, adrenal glands, stomach, small bowel, colon, and rectum. Although volumes of adult liver, spleen, pancreas, and kidneys do not change significantly with age, adult left and right adrenal gland volumes do significantly increase with age (r = 0.2823, P = 0.0334, and r = 0.3676, P = 0.0049, respectively). Also, the attenuation of adult liver (r = -0.2122, P = 0.0412), spleen (r = -0.4508, P < 0.0001), pancreas (r = -0.5124, P = 0.0007), and left and right adrenal gland (r = -0.5835, P < 0.0001 and r = -0.6135, P < 0.0001, respectively) decrease significantly with increasing age. Every organ studied in the pediatric population demonstrates a positive association between organ volume and age. Significant age-related changes in organ function are noted in the adult liver and small bowel, with the liver demonstrating a positive association between metabolic activity and age (r = 0.4434, P = 0.0029) and the small bowel showing an inverse association between mean small bowel standardize uptake value and age (r = -0.2435, P = 0.0174). Also, the maximum overall small bowel and colon metabolic activity in children increases with age (r = 0.6478, P = 0.0008). None of the other organs studied (ie, spleen, pancreas, adrenal glands, stomach, colon, rectum) demonstrate significant changes in metabolism with advancing age. The metabolic volumetric product (calculated as the product of organ volume and mean organ SUV) of the liver and spleen does not change significantly with age. In conclusion, various abdominal organs demonstrate differential changes in volume, attenuation, and/or metabolism with increasing age in pediatric and adult populations.

Age-related structural and metabolic changes in the pelvic reproductive end organs.

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 reviewed 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.

Potential clinical role of fluorodeoxyglucose-positron emission tomography in assessing primary or secondary lymphomas of the parotid gland.

BACKGROUND: We have reviewed the utility of fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging for clinical management of primary parotid lymphoma (by applying strict criteria of primary extranodal involvement by this disease) as well as of cases in which spread of the disease to the parotid gland had occurred as a consequence of primary nodal disease. PATIENTS AND METHODS: A total of 9 cases of parotid lymphoma (5 primary parotid lymphoma and 4 cases of combined nodal/extranodal lymphoma with parotid involvement) were identified and analyzed for this study. A retrospective review of the clinical records, radiologic data, and pathology results was carried out for assessment of the natural course and FDG-PET results in this disease. These patients had undergone conventional whole-body FDGPET or PET/computed tomography for initial or posttherapy monitoring purposes. RESULTS: All cases in both subgroups had unilateral parotid involvement. Fluorodeoxyglucose uptake was focal, and visual assessment was sufficient to detect the disease in all the cases with a sensitivity of 100% in primary and secondary lymphoma of the parotid, independent of the histologic subtypes. The maximum standard uptake value in untreated cases of diffuse large B-cell lymphoma and follicular non-Hodgkin lymphoma of parotid was higher (10.4 and 10.2, respectively) than that of primary parotid marginal zone lymphoma (5.2). Postchemotherapeutic remission was correctly determined by PET in all 3 patients who underwent chemotherapy. The parotid involvement was noted at diagnosis in 2 cases and in the remaining ones up to 30 months after initial diagnosis. Fluorodeoxyglucose uptake was focal and distinct in all cases, and in 1 patient with a parotid nodule as small as 0.5 cm, the lesion was clearly visualized. The maximum standard uptake values in the posttreatment scenario varied from 1.3 to 1.9, which are within the range of what has been observed in the normal parotids. In 4 of 5 patients who underwent treatment monitoring, complete metabolic response in PET was noted in advance of size criteria by radiologic techniques for complete response. CONCLUSION: Despite the known physiologic FDG uptake in parotid glands, FDG-PET appears to be of potential value in managing patients with parotid lymphoma in various stages of disease, including diagnosis and monitoring for therapeutic response.