[Comparative study on diagnosis of fetal dysplasia of spine and spinal cord between B ultrasonography and magnetic resonance imaging].

OBJECTIVE

To compare the value of ultrasound and magnetic resonance imaging (MRI) in detecting fetal spine and spinal cord dysplasia.

METHODS

Thirty women with complicated pregnancies, age from 22 to 41 years, gestation from 23-38 weeks, were studied with MRI within 72 hours after ultrasound studies and revealed 19 cases of fetal spine with irregular, 7 cases of vertebral canal widened partly and 4 cases of anomalies of spinal curvature. Autopsy or imaging was conducted when pregnancy was terminated. A close follow-up was given for cases continuing pregnancy within 12 months after delivery.

RESULTS

(1) Nineteen cases of fetal spine with irregular in ultrasound, the coincidence of antenatal sonographic diagnosis was 42% (8/19), the coincidence of antenatal MRI diagnosis was 89% (17/19). Seven cases of vertebral canal widened partly in ultrasound, the coincidence of antenatal sonographic diagnosis was 0, the coincidence of antenatal MRI diagnosis was 7/7. Four cases of anomalies of spinal curvature in ultrasound, the coincidence of antenatal sonographic diagnosis was 2/4, the coincidence of antenatal MRI diagnosis was 3/4.(2) By MRI study, one cases were conformed their ultrasound diagnosis, eleven cases were completed their ultrasound diagnosis, nine cases were made the same diagnosis as ultrasound and six cases were corrected diagnosis. By MRI and ultrasound study one case of hemivertebra, one case of butterfly vertebra and one case of dorsal dermal sinus were missed diagnosis. Ultrasound had limits and low specificity especially in fetal spinal cord.

CONCLUSIONS

MRI can show the spinal cord and its lesion intuitively and has advantages in displaying fetal anomaly of spine and spinal cord. MRI is a valuable complement to sonography in difficult cases and diagnostic accuracy can be significantly improved.