Spatiotemporal Image Correlation Volume Data Research Articles

Three-Dimensional Printed Model Fabrication and Effectiveness Evaluation in Fetuses With Congenital Heart Disease or With a Normal Heart.

The purpose of this study was to investigate the technical feasibility and accuracy of applying 3-dimensional (3D) printing of normal and abnormal fetal hearts based on spatiotemporal image correlation (STIC) volume-rendered data. Spatiotemporal image correlation volume images of 15 healthy fetuses and 15 fetuses with cardiac abnormalities were collected, and Mimics software (Materialise NV, Leuven, Belgium) was used to postprocess the volume data to obtain a 3D digital model of fetal heart and large blood vessel morphologic characteristics and to output the file to a 3D printer for printing the 3D model of the fetal heart and large blood vessels. The effect accuracy of the 3D printed model was qualitatively evaluated by showing the 3D anatomic structure of the model combined with echocardiographic or autopsy results, and the dimensional accuracy of the 3D printed model was quantitatively evaluated by comparing the measured data of the model and echocardiography. In all 30 fetuses, STIC volume data of the fetal heart were successfully reprocessed and printed out, which could visually display the morphologic characteristics of the fetal heart chamber and passage of the great vessels under normal and abnormal pathologic conditions. No significant differences in all of the heart size parameters were found between the 3D digital model, 3D printed model, and routine echocardiographic images (all P > .05). Moreover, the size parameters were concordant well between the methods, and all of the data points fell within the limits of agreement. It is feasible to 3D print the fetal heart using STIC volumetric images as the data source, and the 3D printed model can fully and accurately display abnormal anatomic structures of the heart.

Study on diagnostic performance of fetal intelligent navigation echocardiography for congenital heart defect

Objective To explore the sensitivity and specificity of fetal intelligent navigation echocardiography(FINE, 5D Heart) in the prenatal detection of congenital heart defect(CHD), and to compare its diagnostic performance with spatiotemporal image correlation(STIC) loop (STICloop). Methods A total of 250 pregnant women having a singleton pregnancy in the second and third trimesters from April 2018 to May 2019 in Sir Run Run Shaw Hospital, Zhejiang University College of Medicine were enrolled in this prospective study. 2D ultrasound diagnosis has been made before acquiring STIC volume data set. After the appropriateness of each volume data set was preliminarily determined, all identifying informations were concealed and the appropriate volumes were randomly distributed to less experienced sonographer for analysis using 5D Heart software. The sensitivity and specificity, positive and negative likelihood ratios, as well as area under the receiver operating characteristic curve (AUC) of the two methods were determined respectively, and the differences between the two methods were statistically analyzed. Results The diagnostic performance of 5D Heart for the prenatal detection of CHD was: sensitivity of 95.45% (105/110), specificity of 94.29% (132/140), positive likelihood ratio of 16.72, negative likelihood ratio of 0.05, and AUC of 0.95, respectively. Among cases with confirmed CHD, the 5D Heart diagnosis completely matched the final diagnosis in 77.27% (85/110). The diagnostic performance of STICloop for the prenatal detection of CHD was: sensitivity of 90.91% (100/110), specificity of 92.86% (130/140), positive likelihood ratio of 12.73, negative likelihood ratio of 0.10, and AUC of 0.92. The sensitivity and secificity of 5D Heart in diagnosing CHD were both higher than 90%, and it could successfully detect a broad spectrum of severe fetal CHD. Among cases with confirmed CHD, even the STICloop diagnosis completely matched the final diagnosis in 61.81%(68/110), its diagnostic accuracy was relatively lower than 5D Heart (P=0.013). However, there were no statistical differences between the two methods in sensitivity and specificity(all P>0.05). Conclusions The sesitivity and specifity of 5D Heart in diagnosis CHD were both higher than 90%, and it could successfully detect a broad spectrum of severe fetal CHD. STICloop could be used for preliminary screening of CHD, as it has the same high sensitivity and specificity as 5D Heart. Further examination may be recommended when fetal heart abnormalities are suspected. Key words: Echocardiography; Congenital heart defect; Fetal intelligent navigation echocardiography; Spatiotemporal image correlation

Feasibility of three dimensional printing of the fetal heart using spatio-temporal image correlation data

Objective To investigate the feasibility of three dimensional(3D) printing fetal heart from spatio-temporal image correlation (STIC) volume-rendered data. Methods Eight fetuses with normal heart and 3 fetuses with confirmed cardiac anomalies identified by two-dimensional echocardiography from February to May 2019 in Renmin Hospital of Wuhan University were prospectively enrolled in this study. All the fetuses underwent two-dimensional (2D) echocardiography and STIC technology examination. The 3D volume images of fetal heart were post-processed by Mimics software to create images of the fetal heart in standard tessellation language format(STL). The STL file was output to the 3D printer and the 3D printing models of fetal heart and great vessels were obtained. In the process, the numerical values of each index of fetal hearts were measured from 3D digital model, 3D printing models and routine echocardiography images, respectively. The accuracy of 3D modeling was assessed by comparing the measured values of the model with the measured values of the source data. Results In all the fetuses, STIC volume data of the fetal heart were successfully reprocessed and printed out, the anatomical structure and vascular course could be visually displayed. It showed no significant difference in all the heart size parameters between 3D digital model, 3D printing models and routine echocardiography images (all P>0.05). Moreover, the size parameters were concordant well between the two methods, all of the data points fell within the limits of agreement. Conclusions The 3D printing of fetal heart using STIC volume images as the data source is feasible. Key words: Three dimensional printing; Spatio-temporal image correlation; Congenital heart disease; Fetus

Is Fetal Intelligent Navigation Echocardiography Helpful in Screening for d-Transposition of the Great Arteries?

To evaluate the performance of fetal intelligent navigation echocardiography (FINE) applied to spatiotemporal image correlation (STIC) volumes in generating 3 specific abnormal cardiac views (left ventricular outflow tract, right ventricular outflow tract, and 3-vessel and trachea) used to screen for d-transposition of the great arteries (d-TGA). In this prospective study, 1 or more STIC volumes were obtained from the 4-chamber view in 34 second- and third-trimester fetuses with d-TGA. Each appropriate STIC volume was evaluated by STICLoop (Samsung Medison, Seoul, Korea) before applying the FINE method. One optimal volume per fetus was selected by observers. The visualization rates of the 3 specific abnormal cardiac views of d-TGA and their diagnostic elements were calculated, and the reliability between 2 observers was verified by the intraclass correlation coefficient. Fetal intelligent navigation echocardiography applied to STIC volume data sets of fetuses with d-TGA successfully generated the 3 specific abnormal cardiac views in the following manner for 2 observers: 75.0% (n = 21) for the left ventricular outflow tract, 89.2% (n = 25) for the right ventricular outflow tract, and 85.7% (n = 24) for the 3-vessel and trachea view. Twenty-four (85.7%) of the STIC volume data sets showed 2 or 3 of the abnormal cardiac views. The interobserver intraclass correlation coefficients between the 2 observers ranged from 0.842 to 1.000 (95% confidence interval), indicating almost perfect reliability for the 2 observers. In cases of d-TGA, the FINE method has a high success rate in generating 3 specific abnormal cardiac views and therefore can be performed to screen for this congenital defect.

Semiautomatic Fetal Intelligent Navigation Echocardiography Has the Potential to Aid Cardiac Evaluations Even in Less Experienced Hands.

To investigate the interobserver and intraobserver variability and corresponding learning curve in a semiautomatic approach for a standardized assessment of the fetal heart (fetal intelligent navigation echocardiography [FINE]). A total of 30 stored spatiotemporal image correlation volume data sets of second-trimester fetuses were evaluated by 3 physicians with different levels of expertise in fetal echocardiography by using the FINE approach. Data were analyzed regarding the examination time and proper reconstruction of the diagnostic cardiac planes. The completions and numbers of correct depictions of all diagnostic planes were evaluated by a blinded expert (time t0). To determine interobserver and intraobserver variability, the volumes were reassessed after a 4-week training interval (time t1). All operators were able to perform the investigation on all 30 volumes. At t0, the interobserver variability between the beginner and both the advanced (P = .0013) and expert (P < .0001) examiners was high. Focusing on intraobserver variability at t1, the beginner showed a marked improvement (P = .0087), whereas in advanced and expert hands, no further improvement regarding proper achievement of all diagnostic planes could be noticed (P > .999; P = .8383). The beginner also showed improvement in the mean investigation time (t0, 82.8 seconds; t1, 73.4 seconds; P = .0895); nevertheless, the advanced and expert examiners were faster in completing the examination (t1, advanced, 20.9 seconds; expert, 28.3 seconds; each P < .0001). Based on our results, the FINE technique is a reliable and easily learned method. The use of this semiautomatic work flow-based approach supports evaluation of the fetal heart in a standardized and time-saving manner. A semiautomatic evaluation of the fetal heart might be useful in facilitating the detection of fetal cardiac anomalies.

Feasibility assessment for successfully visualizing the fetal heart utilizing spatiotemporal image correlation.

Spatiotemporal image correlation (STIC) is an excellent imaging modality for observing the fetal heart. High-quality STIC volume data are needed for an antenatal anatomic survey to diagnose congenital heart disease. We aimed to clarify the causes of unsuccessful STIC volume data acquisition and describe a more accurate, efficient STIC examination. This cross-sectional study of 1124 women with fetuses assessed risk factors for unsuccessful acquisition of STIC volume data. Logistic regression analysis quantified the relation between unsuccessful acquisition and clinical variables, including maternal body mass index (BMI), shadowing artifacts due to unexpected fetal limb movement (SAU), estimated fetal weight (EFW), gestational age (GA), use of volume rendering images in four-dimensional ultrasonography (4D-US), fetal heart rate (FHR), maternal age, anterior placenta, and prior lower abdominal surgery. STIC volume data acquisition was unsuccessful in 210 of 1124 (18.6%) cases. SAU, BMI≥28kg/m2, not using volume rendering images in 4D-US, EFW≥1300g, and anterior placenta were independent risk factors for unsuccessful STIC data acquisition. Avoiding SAU was the most important factor for accurate, efficient STIC evaluations for diagnosing congenital heart disease antenatally. The risk was not explained by lack of sonographer proficiency. Volume rendering images in 4D-US is a promising approach to successful acquisition of STIC volume data.

Feasibility Study on Prenatal Cardiac Screening Using Four-Dimensional Ultrasound with Spatiotemporal Image Correlation: A Multicenter Study.

ObjectiveThis study aimed at investigating the feasibility of using the spatiotemporal image correlation (STIC) technology for prenatal cardiac screening, finding factors that influence the offline evaluation of reconstructed fetal heart, and establishing an optimal acquisition scheme.MethodsThe study included 452 gravidae presenting for routine screening at 3 maternity centers at 20–38 gestational weeks. The factors influencing the quality of STIC volume data were evaluated using t test, chi-square test, and logistic regression analysis. The predictive power was evaluated using the receiver operating characteristic (ROC) curve.ResultsAmong the 452 fetuses enrolled, 353 (78.1%) were identified as successful and 99 (21.9%) as failure of evaluation of the reconstructed fetal heart. The total success rate of qualified STIC images was 78.1%. The display rates of reconstructed cardiac views were 86.5% (four-chamber view), 92.5% (left ventricular outflow tract view), 92.7% (right ventricular outflow tract view), 89.9% (three-vessel trachea view), 63.9% (aortic arch view), 81.4% (ductal arch view), 81% (short-axis view of great vessels), 80.1% (long-cava view), and 86.9% (abdominal view). A logistic regression analysis showed that more than 28 gestational weeks [OR = 0.39 (CI 95% 0.16, 0.19), P = 0.035], frequent fetal movements [OR = 0.37 (CI 95% 0.16, 0.87), P = 0.022], shadowing [OR = 0.36 (CI 95% 0.19, 0.72), P = 0.004], spine location at 10–2 o’clock [OR = 0.08 (CI 95% 0.02, 0.27), P = 0.0], and original cardiac view [OR = 0.51 (0.25, 0.89), P = 0.019] had a significant impact on the quality of STIC. The area under the ROC curve was 0.775.ConclusionsFetal cardiac-STIC seems a feasible tool for prenatal screening of congenital heart diseases. The influence factors on the quality of STIC images included the intensity of training, gestational age, fetal conditions and parameter settings. The optimal acquisition scheme may improve the application and widespread use of cardiac STIC.

Viewing rate and reference ranges for papillary muscle areas of the fetal heart using four-dimensional ultrasound in the rendering mode.

The aims of this study were to assess the viewing rate and determine reference ranges ​​for the papillary muscle areas in the fetal atrio-ventricular valves using four-dimensional (4D) ultrasound and spatio-temporal image correlation (STIC) in the rendering mode. This cross-sectional prospective study included 310 4D STIC volume data sets of normal fetuses between 18 weeks 0 day and 34 weeks 0 day of gestation. The papillary muscles were antero-lateral (MPAL) and postero-medial (MPPM) to the mitral valve and antero-superior (MPAS), inferior (MPI) and septal (MPS) to the tricuspid valve. Polynomial regressions were built to determine the reference ranges, and adjustments were made using the determination coefficient (R(2) ). To assess inter-observer reproducibility, the intra-class correlation coefficient (ICC) was used. Identification of the papillary muscles was possible in 89.3% patients. The best-fit regression equations between papillary muscle areas and gestational age were second degree. The inter-observer reproducibility was good (ICC: 0.98 to MPAS, 0.97 to MPI, 0.98 to MPS, 0.98 to MPAL and 0.97 to MPPM). Identification of the papillary muscles of the fetal valves was possible in most of the 4D STIC volume data sets, enabling the determination of reference ranges using the rendering mode. The reference ranges ​​for the papillary muscle areas were determined.

Reference Ranges for Fetal Septum Primum Excursion From 14 to 40 Weeks' Gestation

The purpose of this study was to establish reference ranges for septum primum excursion and the septum primum excursion index. Normal singleton pregnancies with certain dates from 14 to 40 weeks' gestation were enrolled to acquire spatiotemporal image correlation volume data sets. The stored data sets were subsequently displayed offline to measure septum primum excursion and the left atrium diameter. The measured values were regressed to identify the best-fitted model as a function of gestational age and biparietal diameter. A total of 624 volumes were successfully measured, and normal reference ranges for predicting means and standard deviations of septum primum excursion and the septum primum excursion index were established based on best-fitted equations. The septum primum excursion index was relatively constant throughout pregnancy (mean ± SD, 0.474 ± 0.082), whereas septum primum excursion increased with gestational age and biparietal diameter as follows: (1) septum primum excursion = -6.30 + 0.667 × gestational age - 0.009 × gestational age(2); SD of septum primum excursion = 0.219 + 0.02 × gestational age; and (2) septum primum excursion = -3.342 + 1.933 × biparietal diameter - 0.102 × biparietal diameter(2); SD of septum primum excursion = 0.330 + 0.065 × biparietal diameter. Percentile charts for predicting septum primum excursion and equations for Z score calculation were also provided. Normal reference ranges for fetal septum primum excursion and the septum primum excursion index have been provided. These normative data may be useful tools for assessment of hemodynamics through the foramen ovale or left ventricular diastolic function.

Fetal Cardiac Circumference Derived by Spatiotemporal Image Correlation as a Predictor of Fetal Hemoglobin Bart Disease at Midpregnancy

The purpose of this study was to evaluate the efficacy of the fetal cardiac circumference derived by spatiotemporal image correlation (STIC) for predicting fetal hemoglobin (Hb) Bart disease. Pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks' gestation were enrolled. All underwent STIC volume acquisition for analysis of fetal cardiac dimensions and cordocentesis for Hb level and Hb typing analysis. Spatiotemporal image correlation volume data sets were subsequently analyzed offline for cardiac circumference measurements, which were used to evaluate the efficacy in predicting fetal anemia and fetal Hb Bart disease. A total of 88 pregnancies at risk of fetal Hb Bart disease at 17 to 22 weeks were recruited into the study. The cardiac circumference was significantly higher in fetuses with Hb Bart disease than in unaffected fetuses (1.33 and 1.02 multiples of the median [MoM], respectively; P < .001). The cardiac circumference effectively predicted fetal Hb Bart disease (area under the receiver operating characteristic curve, 0.85; 95% confidence interval [CI], 0.73-0.97), with sensitivity of 86.4% (95% CI, 72.0%-100%) and specificity of 78.1% (95% CI, 68.0%-88.3%) using a cutoff point of greater than 1.17 MoM, whereas the cardiothoracic ratio had better efficacy, with sensitivity of 90.9% (95% CI, 78.9%-100%) and specificity of 85.9% (95% CI, 77.4%-94.5%) using a cutoff point of greater than 0.50. At midpregnancy, a cardiac circumference of greater than 1.17 MoM can be used as an alternative sonographic marker for predicting fetal Hb Bart disease, although not perfectly. However, the cardiothoracic ratio seems to be more accurate than the cardiac circumference for such a purpose.

Fetal Aortic Arch Measurements at 14 to 40 Weeks' Gestation Derived by Spatiotemporal Image Correlation Volume Data Sets

The purpose of this study was to establish reference ranges for the transverse aortic arch diameter (TAD) and distal aortic isthmus diameter (DAID) in normal singleton pregnancies (14-40 weeks) based on the 3-vessel/trachea (3VT) view of cardio-spatiotemporal image correlation (STIC) volume data sets. A prospective descriptive study was conducted on uncomplicated singleton pregnancies with healthy fetuses and an accurate gestational age (GA). Cardio-STIC examinations were performed by experienced sonographers using a high-resolution ultrasound machine, and the volume data sets were manipulated to obtain the 3VT view and measured for the TAD and DAID. A total of 554 measurements were performed, ranging from 13 to 30 for each gestational week. The best regression models were as follows: TAD (in millimeters) = -1.01 + 1.69 (GA, in weeks) (r(2) = 0.93; P < .001), and DAID (in millimeters) = -0.85 + 1.54 (GA, in weeks) (r(2) = 0.92; P < .001). A table of nomograms for 5th, 50th, and 95th percentile ranges was constructed. Normative data for the TAD and DAID at each gestational week from 14 to 40 weeks were constructed by a new technique of measurement based on cardio-STIC. These reference ranges may be useful tools for assessment of fetal aortic arch abnormalities.

Tomographic Ultrasound Imaging of the Fetal Heart

In 2003 and 2004, the American College of Radiology, the American Institute of Ultrasound in Medicine, and the American College of Obstetricians and Gynecologists published guidelines for the standard ultrasound examination of the fetus. Each group recommended that the outflow tracts of the fetal heart be examined if technically feasible. One method to accomplish this task is to perform a free-hand sweep of the transducer beam directed in a transverse plane from the 4-chamber view to the fetal neck. One problem with this approach is that the examiner may not direct the beam transversely and, therefore, may not accurately identify the outflow tract anatomy. A new technology, tomographic ultrasound imaging (TUI), allows the examiner to obtain a volume data set that simultaneously displays multiple images at specific distances from the 4-chamber view. This study examined TUI technology for identifying normal and abnormal fetal cardiac anatomy with the use of either static or spatiotemporal image correlation volume data sets. The 4 views used in the screening examination of the outflow tracts of the fetal heart (4-chamber, 5-chamber, 3-vessel, and tracheal views) could be identified with the use of TUI technology in fetuses between 13 and 40 weeks' gestation. Examples of fetuses with abnormal cardiac anatomy of the outflow tracts (tetralogy of Fallot, transposition of the great vessels, and pulmonary stenosis) all showed abnormal anatomy on TUI. Tomographic ultrasound imaging technology enables the fetal examiner to evaluate the 4-chamber view and the outflow tracts in a systematic manner to identify normal and abnormal cardiac anatomy.