MRI DOES NOT CHANGE FETAL CARDIOTOCOGRAPHIC PARAMETERS

The aim of this study was to determine whether magnetic resonance imag ing (MRI) has any effect on fetal cardiotocographic (CTG) parameters o r movement incidence. Sixteen mothers were examined during the last tr imester at 28-39 weeks (mean 33 weeks; SD 4) of gestation due to a sus pected fetal anomaly found in antenatal ultrasonography (US). MR imagi ng was performed using Siemens Magnetom Vision 1.5 T equipment with a 25 mT/m peak gradient amplitude. T2-weighted images were produced with HASTE and TRUE-FISP sequences and T1-weighted images with a 2D FLASH sequence. A four-element phase-array coil was used as the receiver. Be fore and after MRI examination, a computerized analysis of the fetal h eart rate (FHR) was produced. Basal FHR, short-term variation (STV) an d fetal movements were calculated. The mean basal FHR was 136 beats/mi n (SD 11.6) before, and 133 beats/min (SD 8.9) after (P = 0.158). Shor t-term variation was in the normal range for both CTG-tracings: mean 9 .7 ms (SD 2.7) and 8.8 ms (SD 2.8) (P = 0.196). The median for fetal m ovements before MRI was 48/h, and after MRI 24.5/h (P = 0.98). MRI at high field strength with powerful gradients did nut affect fetal heart activity or movement incidence. (C) 1998 John Wiley & Sons, Ltd.