This case involves a 20-week pregnancy (gravida 1 para 0) for which the patient underwent a sonographic examination.
History and symptoms: A 27-year-old woman underwent obstetric ultrasound imaging at 20 weeks' gestation. She had a history of normal menstrual cycles prior to the pregnancy and has reported no vaginal bleeding since becoming pregnant. She had no history of clinically significant illnesses during the current pregnancy.
Clinical examination: The patient’s blood pressure was within normal limits (122/80 mm Hg), as were her other vital signs. Chest examination did not reveal any abnormalities. The abdominal examination findings revealed a fundal height that corresponded to a gestational age of 20 weeks.
Imaging studies: This routine transabdominal obstetric sonography was performed to exclude any congenital fetal anomalies. The patient had not undergone any sonographic study prior to this scan. The images seen in Figure 1, Figure 2, and Figure 3 show the coronal section of the fetal spine and were taken during this routine sonographic examination.
In Figures 1, 2, and 3, the volume of amniotic fluid appears normal. The fetal abdomen also shows no significant abnormality. The placenta is fundic and posterior. No retroplacental hematoma is seen.
The most prominent anatomy in these images is the fetal spine. The fetal head is to the left of the images, and the fetal lower limbs are to the right of the images. The upper cervical and thoracic spines appear normal. However, there is an abnormality within the lower thoracic vertebrae that appears as an echogenic lesion within the spinal canal. It looks linear and extends within the mid-portion of the spinal canal. We cannot further distinguish the abnormality in this region. What are the diagnostic possibilities based on these images, at this stage?
Shall we call this some form of spinal dysraphism or neural closure defect? The most common anomalies that arise are tethered spinal cord, thickened filum terminale, neurenteric cyst, meningocele, and dermal sinus tract. Also, there are the remote possibilities of diplomyelia and diastematomyelia. Let us examine each of these possibilities.
Antony J. Ultrasound image gallery website. Available at: http://www.ultrasound-images.com. Accessed April 6, 2015.
Rumack CM, Wilson SR, Charboneau JW, Levine D, eds. Diagnostic Ultrasound. 4th ed. Philadelphia: Mosby; 2011.
Suma V, Marini A, Panagopoulos P, et al. Diastematomyelia. Available at: http://sonoworld.com/fetus/page.aspx?id=108. Accessed April 6, 2015.