Fetal cardio-vascular and functional Magnetic Resonance Imaging (MRI) using a MR-compatible Doppler-Ultrasound-Sensor

• Applicant: Privatdozent Dr. Björn Schönnagel
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology ; Gynaecology and Obstetrics
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 261420088

Congenital heart defects (CHD) and intrauterine growth restriction (IUGR) are the most common fetal pathologies and are associated with increased morbidity and mortality (Thompson 2012). For prenatal diagnosis of theses pathologies fetal (Doppler-) Ultrasound represents the diagnostic gold standard. Although prenatal diagnosis of CHD is possible, detection is often missed performing fetal ultrasound (Abu-Harb 1994, Clane 1994, Abdul-Khaliq 2011). Additionally, diagnostic sensitivity of fetal ultrasound is limited by several factors, e.g. maternal obesity, oligohydramnion, and fetal position. Also chronic fetal hypoxemia, as the cause of IUGR, can be indirectly diagnosed revealing variations of maternal and fetal blood flow patterns in Doppler Ultrasound examinations. Repeated ultrasound examinations are required for detection of blood flow variations indicating critical fetal hypoxemia, thus helping delivery timing (Baschat 2004). However, these measurements only allow indirect estimation of fetal hypoxemia.Cardio-vascular MRI allows morphological and functional analysis in adults. To avoid motion artefacts by cardiac contraction and vessel pulsation, a usual ECG is applied for cardiac triggering. However, the intrauterine position of the fetus makes conventional ECG triggering impossible, therefore preventing fetal cardio-vascular MRI for diagnostic imaging.The development of a novel MR-compatible Doppler-Ultrasound Sensor (DUS) by our study group allows fetal cardiac triggering and therefore the morphological and functional analysis of the fetal heart and vessels, which was successfully demonstrated in an animal model (Yamamura 2009, Yamamura 2012, Ueberle 2012). Additionally, using the BOLD-technique (MR-oxymetry) the motion-free delineation of fetal vessels would even allow quantitative estimation of fetal blood oxygen saturation.The aim of this project is further development of the DUS for initial application in human fetuses. Therefore, fetal cardio-vascular MRI will be evaluated in fetuses with suspected CHD by comparison with the reference method of fetal ultrasound. The quantitative estimation of fetal oxygenation will be realized by calibration of fetal haemoglobin-oxygen-saturation (in-vitro umbilical cord blood) with in-vivo MR-oxymetry of the greater fetal veesels. Thus, the DUS allowing motion-free depiction of the fetal heart and vessels, has the potential to improve the prenatal diagnosis and prognosis of CHD and IUGR.

• DFG Programme: Research Grants
• Participating Persons: Dr. Chressen Remus; Dr. Manuela Tavares de Sousa; Privatdozent Dr. Jin Yamamura