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.