Temporal frequency requirements for tissue velocity imaging of the fetal heart
| Autor: | K. Ferm-Widlund, Magnus Westgren, Nina Elmstedt, Lars-Åke Brodin, Britta Lind |
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| Rok vydání: | 2011 |
| Předmět: |
High velocity
Heart Ventricles Fetal heart Gestational Age Fetal Heart Pregnancy medicine Image Processing Computer-Assisted Humans Radiology Nuclear Medicine and imaging Short duration Tissue velocity Radiological and Ultrasound Technology medicine.diagnostic_test business.industry Obstetrics and Gynecology Stroke Volume General Medicine Frame rate Echocardiography Doppler Color Reproductive Medicine Temporal resolution Myocardial motion Female business Fetal echocardiography Blood Flow Velocity Biomedical engineering |
| Zdroj: | Ultrasound in obstetricsgynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 38(4) |
| ISSN: | 1469-0705 |
| Popis: | The high velocity and short duration of myocardial motion requires a high sampling rate to obtain adequate temporal resolution; this issue becomes even more important when taking into consideration the high fetal heart rate. In this study we have established optimal sampling requirements for assessing the duration of various cardiac cycle events and myocardial velocities of the fetal heart using color-coded tissue velocity imaging (TVI).Recordings from 30 fetuses were acquired at an initial frame rate of 180-273 frames/s. All TVI recordings were performed from an apical four-chamber view and stored as cineloops of five to 10 consecutive cardiac cycles for subsequent offline analysis using software enabling a reduction in frame rate. Different components of the myocardial velocity curve, obtained from the basal part of the ventricular septum, were measured at the initial frame rate and compared with their equivalents at gradually decreased frame rates.As acquisition frame rate was reduced, there was a marked increase in deviation from the initial values, resulting in an underestimation of all systolic and diastolic velocities. For the measured durations, there was a clear tendency to underestimate isovolumetric contraction and relaxation, and a clear tendency to overestimate ventricular ejection and diastolic E-wave and A-wave. An acceptable ⩽ 5% deviation from the value obtained at the highest frame rate corresponded to measurements obtained at above 150-200 frames/s.A high sampling rate of at least 200 frames/s is necessary for adequate reconstruction of TVI data for the fetal heart. Frame rates that are too low result in considerable loss of temporal and velocity information. |
| Databáze: | OpenAIRE |
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