Ultrasound- based measurements of testicular volume in 6-to 16-year- old boys - intra- and interobserver agreement and comparison with Prader orchidometry

BACKGROUND: Prader orchidometry has been the standard method for evaluating testicular size. As this technique is subjective and tends to overestimate the testicular volume, ultrasound (US) has been proposed as more reliable. OBJECTIVE: To evaluate the intra- and interobserver agreement of US measurements of testicular volume and to compare US with the Prader orchidometer. MATERIALS AND METHODS: Dimensions of the right testicle were measured using US in 57 boys ages 6.5 to 16.4 years (mean: 12.0 years). The measurements were performed twice by one main observer and once by a second observer. A third observer estimated testicular volume using a Prader orchidometer. Agreement was investigated with Bland-Altman plots, summarized as the mean and standard deviation (SD) of differences, 95% limits of agreement and technical error of measurement. RESULTS: Mean intra-observer difference of testicular volume was 2.2%, SD=9.2% (limits of agreement: -20.3 to 15.9%) and technical error of measurement 6.5%. The mean interobserver difference was 4.8%, SD=20.7% (limits of agreement: -35.7 to 45.3%) and technical error of measurement 14.6%. Comparing US and orchidometer volumes required conversion that was nonlinear and volume dependent, estimated as VolOM = 1.96×VolUS0.71. The mean difference after transformation was 0.7% with an SD of 18.0% (limits of agreement: -34.5 to 35.9%). CONCLUSION: Our results showed a small mean intra- and interobserver difference that indicates the potential of US for measurement of testicular volume at group level. The intra-observer error was limited, which justifies its use in longitudinal follow-up of testicular development in an individual child, but the larger interobserver variability indicates the need for good standardization of methods. Agreement between the two methods requires a power transformation.status: publishe

References for Ultrasound Staging of Breast Maturation, Tanner Breast Staging, Pubic Hair, and Menarche in Norwegian Girls

CONTEXT: Discriminating adipose and glandular tissue is challenging when clinically assessing breast development. Ultrasound facilitates staging of pubertal breast maturation (US B), but has not been systematically compared to Tanner breast (Tanner B) staging, and no normative data have been reported. OBJECTIVE: To present normative references for US B along with references for Tanner B, pubic hair (PH), and menarche. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional sample of 703 healthy girls aged 6 to 16 years were examined. MAIN OUTCOME MEASURES: Breast development was determined with US B and Tanner B staging. Tanner PH and menarcheal status were recorded. The age distributions of entry in US B, Tanner B, and PH stages and menarche were estimated with generalized linear and generalized additive models with a probit link. Method agreement was tested with weighted Cohen's kappa. RESULTS: The median (±2SD) ages for thelarche, US B2 and Tanner B2, were 10.2 (7.7, 12.8) and 10.4 (8.0, 12.7) years. The median (±2SD) ages at Tanner PH2 and menarche were 10.9 (8.5, 13.3) and 12.7 (11.0, 16.2) years. Cohen's kappa of agreement (95% confidence interval) between US B and Tanner B was 0.87 (0.85-0.88). When the methods disagreed, US B was usually more advanced. CONCLUSION: Thelarche occurred at a slightly younger age when assessed with ultrasound compared to clinical Tanner staging, although the 2 methods had a very good agreement when determining pubertal breast maturation. A significant decrease of 2.8 months in age at menarche was observed during the past decade in Norwegian girls.status: publishe

Reference data for testicular volume measured with ultrasound and pubic hair in Norwegian boys are comparable with Northern European populations

AIM: To estimate references for testicular volume measured with ultrasound and Tanner stages of pubic hair in Norwegian boys, and to compare the timing of puberty with data from similar populations. METHODS: Testicular volume was derived from ultrasound measurements of testicular volume in a cross-sectional study of 514 healthy boys. A continuous testicular volume for age reference curve was estimated with the LMS method. Tanner stages for pubic hair were clinically assessed in 452 boys. Age references for pubertal milestones were estimated with probit regression. RESULTS: Puberty onset, defined by an ultrasound testicular volume of 2.7 mL, equivalent to an orchidometer volume of 4 mL, occurred at a mean (SD) age of 11.7 (1.1) years. The reference range was 9.7 (3rd) to 13.7 years (97th percentile). Pubic hair (Tanner stage 2) appeared on average at 11.8 (1.2) years with a corresponding reference range of 9.5-14.1 years. CONCLUSION: The references for testicular volume measured with ultrasound are continuous in age and allow for the quantification of pubertal development. The age distribution of reaching pubertal milestones was comparable with data from other Northern European countries.status: publishe