Brijesh Kumar Yadav1,2, Sagar Buch3, Uday Krishnamurthy1,2, Pavan Jella1, Edgar Hernandez-Andrade4,5, Anabela Trifan1, Lami Yeo4,5, Sonia S Hassan4,5,6, E Mark Haacke1,2, Roberto Romero7,8,9,10, Jaladhar Neelavalli11,12. 1. Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA. 2. Department of Biomedical Engineering, Wayne State University College of Engineering, Detroit, MI, USA. 3. The MRI Institute for Biomedical Research, Waterloo, Ontario, Canada. 4. Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, MI, USA. 5. Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA. 6. Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA. 7. Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, Maryland and Detroit, MI, USA. prbchiefstaff@med.wayne.edu. 8. Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA. prbchiefstaff@med.wayne.edu. 9. Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA. prbchiefstaff@med.wayne.edu. 10. Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA. prbchiefstaff@med.wayne.edu. 11. Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA. jneelava@med.wayne.edu. 12. Philips Innovation Campus, Philips India Ltd., Bengaluru, India. jneelava@med.wayne.edu.
Abstract
OBJECTIVES: To present the feasibility of performing quantitative susceptibility mapping (QSM) in the human fetus to evaluate the oxygenation (SvO2) of cerebral venous blood in vivo. METHODS: Susceptibility weighted imaging (SWI) data were acquired from healthy pregnant subjects (n = 21, median = 31.3 weeks, interquartile range = 8.8 weeks). The susceptibility maps were generated from the SWI-phase images using a modified QSM processing pipeline, optimised for fetal applications. The processing pipeline is as follows: (1) mild high-pass filtering followed by quadratic fitting of the phase images to eliminate background phase variations; (2) manual creation of a fetal brain mask that includes the superior sagittal sinus (SSS); (3) inverse filtering of the resultant masked phase images using a truncated k-space approach with geometric constraint. Further, the magnetic susceptibility, ∆χv and corresponding putative SvO2 of the SSS were quantified from the generated susceptibility maps. Systematic error in the measured SvO2 due to the modified pipeline was also studied through simulations. RESULTS: Simulations showed that the systematic error in SvO2 when using a mask that includes a minimum of 5 voxels around the SSS and five slices remains < 3% for different orientations of the vessel relative to the main magnetic field. The average ∆χv in the SSS quantified across all gestations was 0.42 ± 0.03 ppm. Based on ∆χv, the average putative SvO2 in the SSS across all fetuses was 67% ± 7%, which is in good agreement with published studies. CONCLUSIONS: This in vivo study demonstrates the feasibility of using QSM in the human fetal brain to estimate ∆χv and SvO2. KEY POINTS: • A modified quantitative susceptibility mapping (QSM) processing pipeline is tested and presented for the human fetus. • QSM is feasible in the human fetus for measuring magnetic susceptibility and oxygenation of venous blood in vivo. • Blood magnetic susceptibility values from MR susceptometry and QSM agree with each other in the human fetus.
OBJECTIVES: To present the feasibility of performing quantitative susceptibility mapping (QSM) in the human fetus to evaluate the oxygenation (SvO2) of cerebral venous blood in vivo. METHODS: Susceptibility weighted imaging (SWI) data were acquired from healthy pregnant subjects (n = 21, median = 31.3 weeks, interquartile range = 8.8 weeks). The susceptibility maps were generated from the SWI-phase images using a modified QSM processing pipeline, optimised for fetal applications. The processing pipeline is as follows: (1) mild high-pass filtering followed by quadratic fitting of the phase images to eliminate background phase variations; (2) manual creation of a fetal brain mask that includes the superior sagittal sinus (SSS); (3) inverse filtering of the resultant masked phase images using a truncated k-space approach with geometric constraint. Further, the magnetic susceptibility, ∆χv and corresponding putative SvO2 of the SSS were quantified from the generated susceptibility maps. Systematic error in the measured SvO2 due to the modified pipeline was also studied through simulations. RESULTS: Simulations showed that the systematic error in SvO2 when using a mask that includes a minimum of 5 voxels around the SSS and five slices remains < 3% for different orientations of the vessel relative to the main magnetic field. The average ∆χv in the SSS quantified across all gestations was 0.42 ± 0.03 ppm. Based on ∆χv, the average putative SvO2 in the SSS across all fetuses was 67% ± 7%, which is in good agreement with published studies. CONCLUSIONS: This in vivo study demonstrates the feasibility of using QSM in the human fetal brain to estimate ∆χv and SvO2. KEY POINTS: • A modified quantitative susceptibility mapping (QSM) processing pipeline is tested and presented for the human fetus. • QSM is feasible in the human fetus for measuring magnetic susceptibility and oxygenation of venous blood in vivo. • Blood magnetic susceptibility values from MR susceptometry and QSM agree with each other in the human fetus.
Entities:
Keywords:
Brain; Magnetic resonance imaging; Second trimester
Authors: Sharon Portnoy; Natasha Milligan; Mike Seed; John G Sled; Christopher K Macgowan Journal: Magn Reson Med Date: 2017-10-24 Impact factor: 4.668
Authors: Matthias Stuber; René M Botnar; Stefan E Fischer; Rolf Lamerichs; Jouke Smink; Paul Harvey; Warren J Manning Journal: Magn Reson Med Date: 2002-09 Impact factor: 4.668
Authors: Stephanie A Giza; Simran Sethi; Lauren M Smith; Mary-Ellen E T Empey; Lindsay E Morris; Charles A McKenzie Journal: J Dev Orig Health Dis Date: 2020-12-14 Impact factor: 2.401