Location of the ovaries in girls from newborn to 18 years of age: Reconsidering ovarian shielding

Background: Guidelines for ovarian shielding are to place a lead shield in the midline of the abdomen at the level of the umbilicus. However, the ovaries are routinely seen at other locations on all types of imaging examinations. Objective: To determine the position of the ovaries in girls, newborn to 18 years of age, in order to assess efficacy of ovarian shield placement. Materials and methods: We identified 336 girls who underwent lumbar spine and pelvic MRI. Images were reviewed noting the position of the ovaries relative to anatomic landmarks: symphysis pubis, iliac crest and anterior superior iliac spine (ASIS). In 174 girls a total of 307 ovaries were visualized. The girls were divided into three age groups and analyzed together. Right and left ovaries were analyzed together. The mean, 95% confidence interval (CI), standard deviations and range were calculated. Results: The ovaries lay at or below the iliac crest (the level of the umbilicus), most often just medial to the ASIS and above the pubic symphysis in girls of all ages. Conclusion: Current methods of shielding only the midline of the pelvis for the purpose of reducing radiation dose to the ovaries during radiographic imaging are ineffective given that the ovaries are almost always positioned laterally in the pelvis. Therefore current shielding techniques should be changed; lead ovarian shields should be placed in a lateral position or even abandoned if relevant anatomy will be obscured.