Salma Jabak1, Trisha V Vigneswaran1,2, Marietta Charakida3, Taner Kasapoglu1, Jader de Jesus Cruz4, John M Simpson1,2, Vita Zidere5,6. 1. Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, United Kingdom. 2. Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St. Thomas' Hospitals, London, United Kingdom. 3. School of Biomedical Engineering and Imaging Sciences, Kings College London, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom. 4. Maternidade Dr Alfredo da Costa, Fetal Medicine Center, Lisbon, Portugal. 5. Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, United Kingdom, vita.zidere@nhs.net. 6. Department of Congenital Heart Disease, Evelina London Children's Hospital, Guy's and St. Thomas' Hospitals, London, United Kingdom, vita.zidere@nhs.net.
Abstract
BACKGROUND: In the first trimester, ultrasound confirmation of normal or abnormal cardiac anatomy is difficult. B-mode and colour flow Doppler (CFD) are used to assess the foetal heart. Superb microvascular imaging (SMI) can visualise blood flow within the heart and vessels in early gestation. OBJECTIVE: We report an initial experience of SMI for visualisation of normal and abnormal cardiac anatomy in the first trimester. METHODS: Transabdominal foetal echocardiography was performed between 11 + 6 and 14 + 3 weeks (Aplio 500 US system, Toshiba Medical Systems, Tokyo, Japan) from January 2017 to December 2017. All scans were performed at a tertiary foetal cardiology unit. To assess the potential utility of the technique for early gestation screening, normal scans were reviewed by foetal medicine trainees with respect to the B-mode, CFD and SMI. Three key views were selected to compare modalities: the 4-chamber view, outflow tracts and the 3-vessel and trachea view (VTV). Visualisation rates of key echocardiographic features of significant cardiac abnormalities by SMI were reviewed. RESULTS: Fifty-five normal echocardiograms and 34 cardiac abnormalities were included. In the normal heart, when B-mode, CFD and SMI were assessed separately, SMI had the highest rate of visualisation of 4-chamber, outflow tracts and 3-VTV (93, 85 and 83%, respectively). Intra-observer reliability was moderate for SMI of the 3 standard views (kappa 1, 0.64 and 0.64); inter-observer for 4-chamber and outflow tract views was moderate (kappa 0.64 and 0.77). In 29/34 abnormal cases, SMI showed key features, enhancing greyscale visualisation. CONCLUSION: SMI has potential to become a useful, complementary modality for early foetal echocardiography. Further prospective studies are warranted to establish the place of the technique in assessment of the first trimester foetal heart.
BACKGROUND: In the first trimester, ultrasound confirmation of normal or abnormal cardiac anatomy is difficult. B-mode and colour flow Doppler (CFD) are used to assess the foetal heart. Superb microvascular imaging (SMI) can visualise blood flow within the heart and vessels in early gestation. OBJECTIVE: We report an initial experience of SMI for visualisation of normal and abnormal cardiac anatomy in the first trimester. METHODS: Transabdominal foetal echocardiography was performed between 11 + 6 and 14 + 3 weeks (Aplio 500 US system, Toshiba Medical Systems, Tokyo, Japan) from January 2017 to December 2017. All scans were performed at a tertiary foetal cardiology unit. To assess the potential utility of the technique for early gestation screening, normal scans were reviewed by foetal medicine trainees with respect to the B-mode, CFD and SMI. Three key views were selected to compare modalities: the 4-chamber view, outflow tracts and the 3-vessel and trachea view (VTV). Visualisation rates of key echocardiographic features of significant cardiac abnormalities by SMI were reviewed. RESULTS: Fifty-five normal echocardiograms and 34 cardiac abnormalities were included. In the normal heart, when B-mode, CFD and SMI were assessed separately, SMI had the highest rate of visualisation of 4-chamber, outflow tracts and 3-VTV (93, 85 and 83%, respectively). Intra-observer reliability was moderate for SMI of the 3 standard views (kappa 1, 0.64 and 0.64); inter-observer for 4-chamber and outflow tract views was moderate (kappa 0.64 and 0.77). In 29/34 abnormal cases, SMI showed key features, enhancing greyscale visualisation. CONCLUSION: SMI has potential to become a useful, complementary modality for early foetal echocardiography. Further prospective studies are warranted to establish the place of the technique in assessment of the first trimester foetal heart.