No abstract

Background: Despite its many advantages, experience with fetal magnetic resonance imaging (MRI) is limited, as is knowledge of how fetal tissue relaxation times change with gestational age (GA). Quantification of fetal tissue relaxation times as a function of GA provides insight into tissue changes during fetal development and facilitates comparison of images across time and subjects. This, therefore, can allow the determination of biophysical tissue parameters that may have clinical utility. Purpose: To demonstrate the feasibility of quantifying previously unknown T 1 and T 2 * relaxation times of fetal tissues in uncomplicated pregnancies as a function of GA at 1.5 T. Study Type: Pilot. Population: Nine women with singleton, uncomplicated pregnancies (28-38 weeks GA). Field Strength/Sequence: All participants underwent two iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) acquisitions at different flip angles (6 and 20 ) at 1.5 T. Assessment: Segmentations of the lungs, liver, spleen, kidneys, muscle, and adipose tissue (AT) were conducted using water-only images and proton density fat fraction maps. Driven equilibrium single pulse observation of T 1 (DESPOT 1 ) was used to quantify the mean water T 1 of the lungs, intraabdominal organs, and muscle, and the mean water and lipid T 1 of AT. IDEAL T 2 * maps were used to quantify the T 2 * values of the lungs, intraabdominal organs, and muscle. Statistical Tests: F-tests were performed to assess the T 1 and T 2 * changes of each analyzed tissue as a function of GA. Results: No tissue demonstrated a significant change in T 1 as a function of GA (lungs [P = 0.

3D water-fat MRI can reliably measure volume and quantify lipid content of fetal subcutaneous adipose tissues.

No abstract

4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018.