Greggory R. DeVore

Spatio‐temporal image correlation (STIC): new technology for evaluation of the fetal heart

Spatio‐temporal image correlation (STIC) is a new approach for clinical assessment of the fetal heart. It offers an easy to use technique to acquire data from the fetal heart and to aid in visualization with both two‐dimensional and three‐dimensional (3D) cine sequences. The acquisition is performed in two steps: first, images are acquired by a single, automatic volume sweep. Second, the system analyzes the image data according to their spatial and temporal domain and processes an online dynamic 3D image sequence that is displayed in a multiplanar reformatted cross‐sectional display and/or a surface rendered display. The examiner can navigate within the heart, re‐slice, and produce all of the standard image planes necessary for a comprehensive diagnosis. The advantages of STIC for use in evaluation of the fetal heart are as follows: the technique delivers a temporal resolution which corresponds to a B‐mode frame rate of approximately 80 frames/s; it provides the examiner with an unlimited number of images for review; it allows for correlation between image planes that are perpendicular to the main image acquisition plane; it may shorten the evaluation time when complex heart defects are suspected; it enables the reconstruction of a 3D rendered image that contains depth and volume which may provide additional information that is not available from the thin multiplanar image slices (e.g. for pulmonary veins, septal thickness); it lends itself to storage and review of volume data by the examiner or by experts at a remote site; it provides the examiner with the ability to review all images in a looped cine sequence. Copyright

ISUOG Practice Guidelines (updated): sonographic screening examination of the fetal heart

The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) is a scientific organization that encourages safe clinical practice and high-quality teaching and research related to diagnostic imaging in women’s healthcare. The ISUOG Clinical Standards Committee (CSC) has a remit to develop Practice Guidelines and Consensus Statements that provide healthcare practitioners with a consensus-based approach for diagnostic imaging. They are intended to reflect what is considered by ISUOG to be the best practice at the time at which they are issued. Although ISUOG has made every effort to ensure that Guidelines are accurate when issued, neither the Society nor any of its employees or members accept any liability for the consequences of any inaccurate or misleading data, opinions or statements issued by the CSC. The ISUOG CSC documents are not intended to establish a legal standard of care because interpretation of the evidence that underpins the Guidelines may be influenced by individual circumstances, local protocol and available resources. Approved Guidelines can be distributed freely with the permission of ISUOG (info@isuog.org).

The ‘spin’ technique: a new method for examination of the fetal outflow tracts using three‐dimensional ultrasound

The prenatal detection of congenital heart defects remains one of the most difficult challenges for the sonologist/sonographer when performing the second‐ or third‐trimester screening examination. The four‐chamber view has been used for a number of years as the primary screening image for detection of heart defects, but the inclusion of the right and left outflow tracts increases the detection of cardiac malformations. One of the difficulties, however, is obtaining and interpreting two‐dimensional images of the outflow tracts. This paper reviews a new technique using three‐dimensional (3D) multiplanar imaging that allows the examiner to identify the outflow tracts within a few minutes of acquiring the 3D volume dataset by rotating the volume dataset around the x‐ and y‐axes.

Three- and 4-Dimensional Ultrasound in Obstetrics and Gynecology Proceedings of the American Institute of Ultrasound in Medicine Consensus Conference

The American Institute of Ultrasound in Medicine convened a panel of physicians and scientists with interest and expertise in 3‐dimensional (3D) ultrasound in obstetrics and gynecology to discuss the current diagnostic benefits and technical limitations in obstetrics and gynecology and consider the utility and role of this type of imaging in clinical practice now and in the future. This conference was held in Orlando, Florida, June 16 and 17, 2005. Discussions considered state‐of‐the‐art applications of 3D ultrasound, specific clinical situations in which it has been found to be helpful, the role of 3D volume acquisition for improving diagnostic efficiency and patient throughput, and recommendations for future investigations related to the utility of volume sonography in obstetrics and gynecology.

The importance of the cerebroplacental ratio in the evaluation of fetal well-being in SGA and AGA fetuses

The cerebroplacental ratio (CPR) is emerging as an important predictor of adverse pregnancy outcome, and this has implications for the assessment of fetal well-being in fetuses diagnosed as small for gestational age (SGA) and those appropriate for gestational age close to term. Interest in this assessment tool has been rekindled because of recent reports associating an abnormal ratio with adverse perinatal events and associated postnatal neurological outcome. Fetuses with an abnormal CPR that are appropriate for gestational age or have late-onset SGA (>34 weeks of gestation) have a higher incidence of fetal distress in labor requiring emergency cesarean delivery, a lower cord pH, and an increased admission rate to the newborn intensive care unit when compared with fetuses with a normal CPR. Fetuses with early-onset SGA (<34 weeks of gestation) with an abnormal CPR have a higher incidence of the following when compared with fetuses with a normal CPR: (1) lower gestational age at birth, (2) lower mean birthweight, (3) lower birthweight centile, (4) birthweight less than the 10th centile, (5) higher rate of cesarean delivery for fetal distress in labor, (6) higher rate of Apgar scores less than 7 at 5 minutes, (7) an increased rate of neonatal acidosis, (8) an increased rate of newborn intensive care unit admissions, (9) higher rate of adverse neonatal outcome, and (10) a greater incidence of perinatal death. The CPR is also an earlier predictor of adverse outcome than the biophysical profile, umbilical artery, or middle cerebral artery. In conclusion, the CPR should be considered as an assessment tool in fetuses undergoing third-trimester ultrasound examination, irrespective of the findings of the individual umbilical artery and middle cerebral artery measurements. A CPR calculator is available at http://www.ajog.org/pb/assets/raw/Health%20Advance/journals/ymob/CPR/index.htm.

Improving cleft palate/cleft lip antenatal diagnosis by 3-dimensional sonography: the "flipped face" view.

Objective. Three‐dimensional sonography has enhanced the diagnosis of congenital anomalies in the early stages of pregnancy. Both cleft lip and palate remain a diagnostic challenge for the sonographer because of the variable size of the defects as well as their location. Recently, a technique described by Campbell et al (Ultrasound Obstet Gynecol 2003;:–554, 2005; 25:12–18) demonstrated an improved method called the “reverse face” view, which appears to assist in the diagnosis of clefts involving the palate. Methods. The fetal face was initially examined with the fetus in the supine position. Using 3‐dimensional sonography, a static volume was acquired. Following acquisition of the volume, it was rotated 90° so that the cut plane was directed in a plane from the chin to the nose. The volume cut plane was then scrolled from the chin to the nose to examine in sequential order the lower lip, mandible, and alveolar ridge; tongue; upper lip, maxilla, and alveolar ridge; and hard and soft palates. Results. This approach identified the full length and width of the structures of the mouth and palates and allows the examiner to identify normal anatomy as well as clefts of the hard and soft palates. Conclusions. The fetal hard and soft palates of the mouth can be accessed using a new technique, which we call the “flipped face” maneuver, when an adequate volume of the face can be obtained.

Fetal echocardiography : factors that influence imaging of the fetal heart during the second trimester of pregnancy

The four‐chamber view of the heart is an important component of the ultrasonographic examination of the fetus. However, during the second trimester of pregnancy the fetal heart cannot always be imaged in every patient. The purpose of this study was to ascertain the rate of successful imaging of the fetal heart during the second trimester and to determine factors that may influence imaging.

Fetal cardiac dysfunction in preterm premature rupture of membranes

BACKGROUND Preterm premature rupture of membranes (PROM) is associated with one-third of preterm births. In about 50% of preterm PROM cases, the fetuses will elicit a fetal inflammatory response syndrome (FIRS). FIRS is associated with the impending onset of preterm labor, periventricular leukomalacia, neonatal sepsis, and long-term handicap, including the development of bronchopulmonary dysplasia and cerebral palsy. The fetal myocardium is a potential target organ of proinflammatory cytokines released during FIRS. The objective of this study was to determine whether preterm PROM is associated with functional changes in the fetal heart, as determined by fetal echocardiography. METHODS A retrospective study was conducted to assess the diastolic function of fetuses with preterm PROM with documented microbial invasion of the amniotic cavity (n = 25), preterm PROM without microbial invasion of the amniotic cavity (n = 42), and fetuses from normal pregnancies (control group = 150). Pregnancies with multiple gestation, fetal distress, fetuses that were small for gestational age, and major congenital anomalies were excluded. Fetal echocardiography studies were performed with two-dimensional ultrasound, color Doppler imaging and pulsed Doppler ultrasound. Non-parametric statistics were used for comparisons. A p value of < 0.05 was considered significant. RESULTS The prevalence of positive amniotic fluid cultures for micro-organisms in patients with preterm PROM was 35.8% (24/67). Ureaplasma urealyticum was the most frequent isolate, either alone (41.7%; 10/24) or with other micro-organisms (29.2%; 7/24). Fetuses with preterm PROM had a higher delta early diastolic filling/atrial contraction (E/A) peak velocity ratio, a higher delta E/A velocity-time integral (VTI) ratio, a lower delta A peak velocity, a lower delta A VTI, and a lower A VTI/total VTI ratio in the mitral valve compared to those with uncomplicated pregnancies. The delta E/A peak velocity ratio was significantly higher and the delta A VTI significantly lower in fetuses with preterm PROM and microbial invasion of the amniotic cavity than in those with preterm PROM without microbial invasion of the amniotic cavity. CONCLUSIONS Preterm PROM is associated with changes in fetal cardiac function consistent with increased left ventricular compliance. These observations were also noted in fetuses with microbial invasion of the amniotic cavity. Our findings suggest that fetal cardiac function is altered in preterm PROM and, in particular, in cases with intra-amniotic infection.

Fetal echocardiography. I. Normal anatomy as determined by real-time--directed M-mode ultrasound.

With current ultrasound technology, it is now possible to obtain accurate real-time and M-mode information from the fetal heart with the use of real-time--directed M-mode echocardiography. With this method, the M-mode cursor is directed to the fetal cardiac structures of interest while the image is obtained in the real-time mode. This enables M-mode echocardiograms to be obtained in an accurate, reproducible manner. The most useful imaging planes for cardiac evaluation are the long axis four-chamber plane, the short axis plane through the atrioventricular valves, and the short axis plane through the aortic and pulmonic outflow tracts. Once normal fetal cardiac anatomy is understood, structural defects and/or alterations of function can be evaluated accurately antenatally.

An 8‐Center Study to Evaluate the Utility of Midterm Genetic Sonograms Among High‐Risk Pregnancies

Objective. A multicenter study was undertaken to evaluate the diagnostic efficacy of a genetic sonogram. Methods. Eight centers provided data on 176 pregnancies complicated by fetal Down syndrome. One hundred thirty‐four pregnancies were considered high risk because of advanced maternal age (>35 years), and 42 were considered high risk for having “abnormal” triple‐screen results (risk >1:250). Each center provided fetal biometric data, information regarding the presence or absence of major structural abnormalities, and between 3 and 6 additional ultrasonographic markers for trisomy 21. The heterogeneity of our 8 independent “sensitivity estimates” was evaluated by Poisson regression, and a single combined estimate of the sensitivity was calculated. Results. Of the total 176 cases of trisomy 21, 125 fetuses (71.0%) had either an abnormal long bone length (femur length, humerus length, or both), a major structural abnormality, or a Down syndrome marker. The combined diagnostic sensitivity was 71.6%, with a range of 63.6% (7 of 11) to 80% (8 of 10). Five centers had sensitivity estimates falling between 64% and 76%. The sensitivity of individual markers varied between 3% (sandal gap) and 46.5% (nuchal skin fold thickness). A condensed regimen of nuchal skin fold thickness, femur length, and a standard anatomic survey would screen in 56.8% of fetuses with Down syndrome. Conclusions. This 8‐center study that included many fetuses with Down syndrome validates the concept that the genetic sonogram can be used to better adjust the Down syndrome risk for high‐risk patients.