Pelvic ultrasonography cannot alone be used to diagnose pubertal anomalies

The question whether the ultrasonographic appearance is useful for differentiating between pubertal anomalies is answered in the November 1998 issue of Acta Paediatrica by Buzi et al. (1) in the article entitled “Pelvic ultrasonography in normal girls and in girls with pubertal precocity”. The sonographic appearance differs significantly between different pathologic conditions and normal girls of the same age. However, it varies widely, with an overlap between the conditions, and cannot be used as the only means of diagnosing pubertal anomalies. This has been shown previously (2). The wide variation in sonographic measurements is due partly to biological variation and partly to ultrasonography. The definition of pubertal anomalies was originally based on clinical and endocrinological findings. It was not known how often the genital organs showed abnormalities and whether such changes were clinically relevant. It is therefore not surprising that the sonographic appearance of the genitalia in patients with pubertal anomalies varies. As the correlation between endocrinological and ultrasound changes is weak, ultrasound has little diagnostic value in the single case. A similar dilemma has arisen in the diagnosis of polycystic ovary syndrome. Women with hirsutism, irregular periods and infertility often have endocrinological abnormalities and polycystic ovaries are found at surgery. However, between 10% and 17% of normal women coming for a cervical smear (3, 4) had polycystic ovaries as detected by ultrasound. Not all, but between 50% and 80% of these had other clinical findings and symptoms related to the polycystic ovary syndrome. On the other hand, polycystic ovaries are not always found by ultrasound in women with other clinical findings and symptoms of the polycystic ovary syndrome (5). The biological variation concerning the ovaries is wide in this condition. The definition did not originally include ultrasonographic appearance and perhaps should not do so. It is possible that patients with polycystic ovaries only have a mild form of the polycystic ovary syndrome, but we do not know. The variation due to the method of ultrasound may also be wide. All authors agree on the fact that ultrasound is user-dependent. Why is this? It is obvious that an operator must handle the ultrasound machine and has to be skilled. Also, in many cases it is not clear what to look for. The definition of an ovary is an almond-shaped structure, less echogenic than the intestines and around 1–3 cm, with or without echofree spaces. There is no proof that such an object really is the ovary. The operator may interpret the picture to different degrees of accuracy. Ultrasound is also patient-dependent. Visualization is hampered by failure to fill the urinary bladder and obesity. Different ultrasound equipment may also give different pictures. I terand intraobserver variation is therefore only applicable to a fixed situation. Further, the prolate ellipsoid formula used for calculating ovarian volumes is subject to considerable error. Small measuring errors tend to be multiplied due to the formula, and the error tends to increase when small volumes are being measured (6). When measuring ovaries, the volumes tend to be very small. Interobserver variation when measuring PMP ovaries in our hands has an r-value of 0.86. When measuring PMP ovaries removed during autopsy with a ruler in three planes, calculating the volume and comparing the results with that obtained when the ovary was immersed in water, we found an rvalue of 0.84. Finally, when first measuring ovaries with ultrasound and then with the ruler at laparotomy, an rvalue of 0.67 was found (7). Buzi et al. (1) also propose a more detailed terminology in defining ovarian ultrasound appearance. A similar terminology was proposed by us in 1997 (8) considering the appearance of the ovaries in anorectic women. During psychiatric treatment and subsequent weight gain these women go through the same stages as in puberty. Initially, only three stages of ovarian appearance were proposed in the literature concerning anorectic women (9). Buzi (1) proposes a total of six stages. In our study of women with eating disorders we proposed four stages. In this study, changes of the genitalia were seen with ultrasound as symptoms of eating disorders regressed, but these changes could not be correlated to clinical parameters, as the variations also in these conditions were wide. In conclusion, ultrasound has little value in the diagnosis of endocrinological disorder in the single case, although in studies of groups of patients with endocrinological disorders it may give important information.