title: Non-gated fetal MRI of umbilical blood flow in an acardiac twin.
abstract: Currently, the standard method of diagnosis of twin reversed arterial perfusion (TRAP) sequence is ultrasound imaging. The use of MRI for flow visualization may be a useful adjunct to US imaging for assessing the presence of retrograde blood flow in the acardiac fetus and/or umbilical artery. The technical challenge in fetal MRI flow imaging, however, is that fetal electrocardiogram (ECG) monitoring required for flow imaging is currently unavailable in the MRI scanner. A non-gated MRI flow imaging technique that requires no ECG monitoring was developed using the t-test to detect blood flow in 20 slices of phase-contrast MRI images randomly scanned at the same location over multiple cardiac cycles. A feasibility study was performed in a 24-week acardiac twin that showed no umbilical flow sonographically. Non-gated MRI flow images clearly indicated the presence of blood flow in the umbilical artery to the acardiac twin; however, there was no blood flow beyond the abdomen. This study leads us to conjecture that non-gated MRI flow imaging is sensitive in detecting low-range blood flow velocity and can be an adjunct to Doppler US imaging.
authors.affiliation: Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan. hata@bwh.harvard.edu
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Hata
authors.forename: Toru
authors.initials: T
authors.lastname: Wada
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kashima
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Okada
authors.forename: Nobuya
authors.initials: N
authors.lastname: Unno
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kitagawa
authors.forename: Toshio
authors.initials: T
authors.lastname: Chiba
mesh_terms: D000328:Adult; D004200:Diseases in Twins; D005260:Female; D005318:Fetal Heart / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011859:Radiography; D012039:Regional Blood Flow / Q000502:physiology*; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000002:abnormalities / Q000000981:diagnostic imaging; D014470:Umbilical Cord / Q000098:blood supply* / Q000000981:diagnostic imaging