Ultrasound in Pediatric Emergencies

Gaurav Saigal, MD, Jennifer Runco Therrien, MD, and Frank Kuo, BS


Appl Radiol. 2014;43(8) 

In This Article

Pelvic Pathology


US is the imaging modality of choice for evaluating the pediatric female pelvis to exclude or diagnose emergency surgical conditions, including ovarian torsion, ectopic pregnancy and abscess. Functional ovarian (follicular) cysts result from failure of involution during the normal menstrual cycle. Bleeding into or rupture of a functional ovarian cyst is a cause of pain and may mimic acute appendicitis.[21] Non-hemorrhagic ovarian cysts appear as avascular, anechoic, thin-walled masses with posterior acoustic enhancement. Most cysts are small and resolve without treatment, but some may be large (up to 6 cm), in which case follow-up is recommended to ensure resolution. The US appearance of hemorrhagic cysts depends on the age of the blood, but typically they appear as avascular complex adnexal masses with septations and internal echoes in a "lace-like pattern" with some degree of through transmission.[22,23]

Congenital Anomalies

Congenital anomalies are not infrequently encountered in the ED as a cause of pain in the female child or adolescent. Hydrocolpos, hydrometrocolpos and hematametrocolpos in adolescents are typically caused by an imperforate hymen, leading to filling of the uterus and/or vagina with fluid and blood. US demonstrates a pelvic cystic mass with a fluid-debris level (Figure 12A-C).[21,22] Many cases of hydrometrocolpos in the neonate are associated with a urogenital sinus or cloacal malformation.[21,23] Failure of the Mullerian or para-mesonephric ducts to reach the urogenital sinus causes accumulation of uterine secretions proximal to the vaginal occlusion. This anomaly may present as a bulging mass between the labia in neonates or with primary amenorrhea and cyclical lower abdominal pain in adolescents.[22]

Figure 12.

An 11-year-old girl presented with pelvic pain. Relevant history was that the patient had never previously menstruated. On sagittal and transverse (A, B) gray-scale sonographic images of the pelvis, the vagina (solid white arrow) is markedly distended with echogenic material compatible with fluid and blood. The uterus (dotted white arrow) is visualized superior to the vagina on sagittal ultrasound and CT images (A, C) and the endometrial cavity is also distended but to a lesser extent with fluid and blood in this patient with hematometrocolpos.

Ovarian Torsion

Ovarian torsion is more common in patients with predisposing lesions, such as ovarian cysts or masses (teratomas), and is due to excessive mobility of the ovary.[22,24] Presentation is often confusing clinically and includes abrupt onset of severe lower abdominal pain usually preceded by intermittent pain or palpation of a pelvic mass.[23] Torsion initially occludes the venous circulation and, if untreated, progresses to occlude the arterial circulation. On US, the ovary appears diffusely enlarged with multiple peripheral follicles. (Figure 13A-B).[25] Additional findings include a complex pelvic mass, free fluid in the pouch of Douglas and absence of flow on color Doppler. However, lack of flow on color Doppler is not a reliable diagnostic criterion, as arterial flow has been seen in surgically proven ovarian torsion likely due to a dual arterial supply or preceding venous thrombosis.[21,24,25]

Figure 13.

A 13-year-old girl with right-sided pelvic pain. (A) Ultrasound demonstrates an enlarged and heterogeneous-appearing right ovary demonstrating multiple cysts. A dominant large cyst measuring up to 4.7cm (white arrow) was noted. (B) No vascularity was detected on color Doppler. At surgery, the right ovary was torsed and nonviable with omentum caked to it.