Development of the subcortical brain structures in the second trimester: assessment with 7.0-T MRI.

INTRODUCTION

This study aims to obtain the signal intensity changes and quantitative measurements of the subcortical brain structures of 12-22 weeks gestational age (GA).

METHODS

Sixty-nine fetal specimens were selected and scanned by 7.0-T MR. The signal intensity changes of the subcortical brain structures were analyzed. The three-dimensional visualization models of the germinal matrix, caudate nucleus, lentiform nucleus, and dorsal thalamus were rebuilt with Amira 4.1, and the developmental trends between the measurements and GA were analyzed.

RESULTS

The germinal matrix was delineated on 7.0-T MR images at 12 weeks GA, with high signals on T1-weighted images (WI). While at 16 weeks GA, the caudate nucleus, lentiform nucleus, and internal and external capsules could be distinguished. The caudate nucleus was high signal intensity on T1WI. The signal intensity of the putamen was high on T1WI during 15-17 weeks GA and was delineated as an area with uneven signal intensities. The signal intensity of the peripheral area of the putamen became higher after 18 weeks GA. The signal intensity of the globus pallidus was high on T1WI and low on T2WI after 20 weeks GA. At 18 weeks GA, the claustrum was delineated with low signals on T2WI. Measurements of the germinal matrix, caudate nucleus, lentiform nucleus, and dorsal thalamus linearly increased with the GA.

CONCLUSION

Development of the subcortical brain structures during 12-22 weeks GA could be displayed with 7.0-T MRI. The measurement provides significant reference beneficial to the clinical evaluation of fetal brain development.