Fetal brain tissue characterization at 1.5 T using STrategically Acquired Gradient Echo (STAGE) imaging.

Objectives: To estimate human fetal brain MRI tissue properties including apparent T ₁ (T _1app ) and apparent proton density (PD _app ) by using a rapid multi-contrast acquisition protocol called STrategically Acquired Gradient Echo (STAGE) imaging.
Methods: STAGE data were collected using two flip angles (15° and 60°, with a TR = 600 ms) for 30 pregnant women at 1.5 T (15 healthy controls: gestational age (GA) range 19 + 1/7 weeks to 34 + 5/7 weeks; 11 abnormal subjects with ventriculomegaly: GA range 21 + 5/7 weeks to 31 + 5/7 weeks; 4 subjects with other abnormalities). Both T _1app and PD _app maps of the fetal brain were calculated from the STAGE data. A region-of-interest-based approach was used to measure T _1app and PD _app in the subplate/intermediate zone (SP/IZ), cortical plate (CP), and cerebrospinal fluid (CSF) in the fetal brain.
Results: The ratios of T _1appSP/IZ /T _1appCP and PD _appSP/IZ /PD _appCP were larger than unity while T _1appSP/IZ /T _1appCSF and PD _appSP/IZ /PD _appCSF were both less than unity.
Conclusions: STAGE imaging provides a potential practical approach to estimate multi-parametric properties of the human fetal brain.
Key Points: • STAGE is feasible in measuring fetal brain tissue properties. • Water content in cortical plate and subplate/intermediate zone approaches that of cerebrospinal fluid in early gestational ages.
(© 2021. European Society of Radiology.)