Purpose or Case Report: Ultrasound has long been a readily available, noninvasive, and accurate means of evaluating the female pelvis and is widely used in the emergency setting for girls with abdominal and pelvic pain. One key element in evaluating for pathology is to measure ovarian size and compare left and right ovaries. Normative volume data stratified by age are available; however, these studies suffer from lack of numbers, and frequently older equipment. Technological advances in ultrasonic hardware and software have increased the resolution of both gray-scale and Doppler imaging. Increases in spatial resolution allow for better identification and measurement of ovaries and precise measurements and depictions of anatomic details. The purpose of this study was to re-evaluate normal pediatric ovarian volumes in relation to patient age with a larger dataset and newer technology.
Methods & Materials: After IRB approval at a freestanding children's hospital, a database of radiology examinations was queried to pull sequential pelvic ultrasounds for girls that presented to the emergency room with abdominal or pelvic pain from April 2015 to May 2016. Due to limited numbers of younger patients, the database was re-queried for girls from 2006-2017, ages 6 years old or less. Cases with identified ovarian or pelvic pathology including torsion, masses, cysts, and also those with appendicitis were excluded, as were patients with prior oophorectomy. In total, 420 cases were evaluated.
Results: In this cohort the average patient age was 12.2±5.1 years old. A slight majority of the patients had larger right ovaries (53.3%) with on average the dominant ovary being 2.1±3.1 times larger than the contralateral side. Ovarian size was found to increase with age with a linear fit to the data revealing an approximate 0.7 cc increase in volume per year of age (figure 1). For increasing age categories of 0-3, 4-6, 7-10, 11-15, >16 years old, the average ovarian volume was 1.1±1.4, 1.2±1.2, 1.3±0.9, 8.1±8.9 and 9.3±8.4 cc respectively.
Conclusions: An updated case series for normal ovarian sizes is presented. This is useful, particularly in the setting of emergency evaluation for torsion and other pelvic pathology, and can reasonably be extrapolated to the outpatient setting.