[MR-fetography: new possibility of fetal evaluation].

PURPOSE

To evaluate the use of MR-fetography sequences in identifying the major fetal structures and to compare thick and thin-slab acquisitions for their diagnostic value.

MATERIALS AND METHODS

21 consecutive, pregnant women with suspected fetal pathology underwent fetal MRI using a 1.5 Tesla MRI unit. Heavily T2-weighted, SSFSE sequences with a long echo train (MR-fetography) was acquired in a thick and thin-slab modus. Thick and thin-slab acquisitions were reviewed by two experienced radiologists with regard to the overall image quality, graded according to a three-scale grading system (3 - good, 2 - moderate, 1 - poor), and evaluation of major fetal structures; visibility scores for each were calculated and compared.

RESULTS

Overall image quality was graded good in 71.4%, moderate in 23.9% and poor in 4.8% for thick-slab images and good in 81%, moderate in 4.8%, poor in 4.8% for thin-slab images. The visibility scores of the thick /thin-slab images for evaluation of the main fetal structures were as follows: for the spinal canal 2.8 +/- 0.4/2.9 +/- 0.36 (p > 0.05), spinal cord 2.4 +/- 0.75/2.7 +/- 0.66 (p < 0.05), posterior fossa components (brainstem, cerebellum, basal cisterns) 2.4 +/- 0.6/2.7 +/- 0.58 (2.3 +/- 0.66/2.7 +/- 0.66, 2.5 +/- 0.6/2.8 +/- 0.54, 2.6 +/- 0.51/2.7 +/- 0.56; p < 0.05), stomach 2.8 +/- 0.44/2.9 +/- 0.48 (p > 0.05), urinary bladder 2.8 +/- 0.44/2.8 +/- 0.54 (p > 0.05), and umbilical cord 2.9 +/- 0.3/2.7 +/- 0.56 (p < 0.05).

CONCLUSION

Heavily T2-weighted MR-fetography renders a reliable quick survey/ overview of fetal anatomy, contours and size. Thick-slab images display the entire fetus in one projection while thin-slab images provide evaluation of smaller anatomical structures (e.g. spinal cord, posterior fossa components) without suffering from volume averaging effects or overlay projection phenomena.