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Biomedical subjects

Wesley Lee

Publications and source records attributed to Wesley Lee.

At least 19 recordsLinked to original sources
PubMed2006

Isolated choroid plexus separation on second-trimester sonography: natural history and postnatal importance.

OBJECTIVE: This study was undertaken to investigate the natural history and clinical importance of choroid plexus separation (a > or = 3 mm distance between the choroid plexus and medial wall of the lateral ventricle) as an isolated finding in the second trimester. METHODS: This was a 5-year retrospective review of an ultrasound database, looking for singleton fetuses with a menstrual age of 16 to 26 weeks and a finding of isolated choroid plexus separation. RESULTS: There were 78 cases available for study. The finding of choroid plexus separation was usually transient. Resolution was noted in 37% of the cases that were rescanned within 2 weeks and 71% of the cases that were rescanned more than 2 weeks after the initial diagnosis. Two abnormal karyotypes (trisomy 21 and 47,XXY) and 3 cases with abnormal development not associated with an abnormal karyotype were noted on neonatal follow-up. Cases with abnormal development were quite varied in their presentation. CONCLUSIONS: The finding of isolated choroid plexus separation is usually temporary, resolving in most cases within 4 weeks of the initial diagnosis. Most infants with this finding have no abnormalities. The clinical implication of the lone case of trisomy 21 was limited by a major preexisting risk in this patient. The 3 cases of abnormal development had varying presentations; the causal nature of this association is not yet clear. No trends were noted between the changing choroid plexus appearance with time and abnormal neonatal outcome, but the number of abnormal cases was quite limited.

Brain Diseases↗
PubMed2006

What does 2-dimensional imaging add to 3- and 4-dimensional obstetric ultrasonography?

OBJECTIVE: The purpose of this study was to determine whether 2-dimensional (2D) ultrasonography adds diagnostic information to that provided by the examination of 3-dimensional/4-dimensional (3D/4D) volume data sets alone. METHODS: Ninety-nine fetuses were examined by 3D/4D volume ultrasonography. Volume data sets were evaluated by a blinded independent examiner who, after establishing an initial diagnostic impression by 3D/4D ultrasonography, performed a 2D ultrasonographic examination. The frequency of agreement and diagnostic accuracy of each modality to detect congenital anomalies were calculated and compared. RESULTS: Fifty-four fetuses with no abnormalities and 45 fetuses with 82 anomalies diagnosed by 2D ultrasonography were examined. Agreement between 3D/4D and 2D ultrasonography occurred for 90.4% of the findings (123/136; intraclass correlation coefficient, 0.834; 95% confidence interval, 0.774-0.879). Six anomalies were missed by 3D/4D ultrasonography when compared to 2D ultrasonography (ventricular septal defect [n = 2], interrupted inferior vena cava with azygous continuation [n = 1], tetralogy of Fallot [n = 1], horseshoe kidney [n = 1], and cystic adenomatoid malformation [n = 1]). There were 2 discordant diagnoses: transposition of the great arteries diagnosed as a double-outlet right ventricle and pulmonary atresia misinterpreted as tricuspid atresia on 3D/4D ultrasonography. One case of occult spinal dysraphism was suspected on 3D ultrasonography but not confirmed by 2D ultrasonography. When compared to diagnoses performed after delivery (n = 106), the sensitivity and specificity of 3D/4D ultrasonography (92.2% [47/51] and 76.4% [42/55], respectively) and 2D ultrasonography (96.1% [49/51] and 72.7% [40/55]) were not significantly different (P = .233). CONCLUSIONS: Information provided by 2D ultrasonography is consistent, in most cases, with information provided by the examination of 3D/4D volume data sets alone.

Female↗
PubMed2006

Applications of 2-dimensional matrix array for 3- and 4-dimensional examination of the fetus: a pictorial essay.

OBJECTIVES: Two-dimensional (2D) matrix array is a new technology for the performance of 3-dimensional and 4-dimensional (4D) ultrasonography. In this study, we report the use of a 2D matrix array transducer for examination of fetal structures including the fetal heart. METHODS: Thirty-four fetuses without abnormalities and 19 fetuses with congenital anomalies were examined with a 2D matrix array transducer (x3-1, IE-33; Philips Medical Systems, Bothell, WA). Median gestational age was 25 6/7 weeks (range, 13 0/7-40 1/7 weeks). RESULTS: (1) A 360 degrees rotation and examination of selected structures was possible in the second trimester. (2) Structures were examined by maintaining the transducer in a fixed position and rotating the volume using the system trackball. (3) Dorsal and ventral parts of the hands and feet were visualized in a single volume data set, in real time, without moving the transducer. (4) Real-time en face visualization of atrioventricular valves was possible from the ventricular or atrial chambers. (5) Four-dimensional images of bones were obtained by decreasing gain settings only, with no need for cropping. (6) Four-dimensional reconstruction of vascular structures was possible with color Doppler imaging. Two limitations were identified: (1) lower resolution than mechanical volumetric transducers, and (2) narrow volume display. CONCLUSIONS: Real-time direct 4D imaging with 360 degrees rotation for examination of fetal anatomic structures is feasible. This technology allows examination of fetal structures from multiple perspectives, in real time, without the need to move the transducer in the maternal abdomen. Further technological developments may overcome the limitations identified in this study.

Congenital Abnormalities↗
PubMed2006

A novel algorithm for comprehensive fetal echocardiography using 4-dimensional ultrasonography and tomographic imaging.

OBJECTIVE: Tomographic ultrasound imaging (TUI) is a new display modality that allows simultaneous visualization of up to 8 parallel anatomic planes. This study was designed to determine the role of a novel algorithm combining spatiotemporal image correlation and TUI to visualize standard fetal echocardiographic planes. METHODS: Volume data sets from fetuses with and without congenital heart defects (CHDs) were examined with a novel algorithm that allows simultaneous visualization of the 3-vessel and trachea view, the 4-chamber view, and outflow tracts. Visualization rates for these planes as well as the ductal arch and 5-chamber view were calculated. RESULTS: (1) Two hundred twenty-seven volume data sets from fetuses without (n = 138) and with (n = 14) CHDs were reviewed; (2) among fetuses without CHDs, the 4-chamber view, 5-chamber view, ductal arch, 3-vessel and trachea view, left outflow tract, and short axis of the aorta were visualized in 99% (193/195), 96.9% (189/195), 98.5% (192/195), 88.2% (172/195), 93.3% (182/195), and 87.2% (170/195) of the volume data sets, respectively; (3) these views were visualized in 85% (17/20), 80% (16/20), 65% (13/20), 55% (11/20), 55% (11/20), and 70% (14/20) of the volume data sets, respectively, from fetuses with CHDs; and (4) simultaneous visualization of the short axis of the aorta, 3-vessel and trachea view, left outflow tract, and 4-chamber view was obtained in 78% (152/195) of the volume data sets from fetuses without CHDs and in 40% (8/20) of those with CHDs. CONCLUSIONS: The 3-vessel and trachea view, the 4-chamber view, and both outflow tracts can be simultaneously visualized using a novel algorithm combining spatiotemporal image correlation and TUI.

Algorithms↗
PubMed2005

Four-dimensional fetal echocardiography with spatiotemporal image correlation (STIC): a systematic study of standard cardiac views assessed by different observers.

OBJECTIVE: To test the agreement between observers and reproducibility of a technique to display standard cardiac views of the left and right ventricular outflow tracts from four-dimensional volume datasets acquired with Spatiotemporal Image Correlation (STIC). METHODS: A technique was developed to obtain dynamic multiplanar images of the left ventricular outflow tract (LVOT) and right ventricular outflow tract (RVOT) from volume datasets acquired with STIC. Volume datasets were acquired from fetuses with normal cardiac anatomy. Twenty volume datasets of satisfactory quality were pre-selected by one investigator. The data was randomly assigned for a blinded review by two independent observers with previous experience in fetal echocardiography. Only one volume dataset was used for each fetus. After a training session, the observers obtained standardized cardiac views of the LVOT and RVOT, which were scored on a scale of 1 to 5, based on diagnostic value and image quality (1=unacceptable, 2=marginal, 3=acceptable, 4=good, and 5=excellent). Median scores and interquartile range, as well as inter- and intraobserver agreement were calculated for each view. RESULTS: The mean menstrual age at the time of volume acquisition was 25.5+/-4.5 weeks. Median scores (interquartile range) for LVOT images, obtained by the first and second observers, were 3.5 (2.25-5.00) and 4 (3.00-5.00), respectively. The median scores (interquartile range) for RVOT images obtained by the first and second observers were 3 (3.00-5.00) and 3 (2.00-4.00), respectively. The interobserver intraclass correlation coefficient for the LVOT was 0.693 (95% CI 0.380-0.822), and 0.696 (95% CI 0.382-0.866) for the RVOT. For the intraobserver agreement analysis, observer 1 gave higher scores to the LVOT the second time the volumes were analyzed [LVOT: 3.50 (2.25-5.00) vs. 5.00 (4.00-5.00, p=0.008)]. CONCLUSION: STIC can be reproducibly used to evaluate fetal cardiac outflow tracts by independent examiners. Slightly better image quality rating scores during the intraobserver variability trial suggests the presence of a learning curve for the manipulation and analysis of volume data obtained by STIC.

Double-Blind Method↗
PubMed2005

The ultrasonographic appearance of ovarian ectopic pregnancies.

OBJECTIVE: To evaluate the ultrasonographic findings of ovarian ectopic pregnancies. METHODS: The ultrasonographic reports, videotapes, medical records, and operative summaries were reviewed for all women with a confirmed diagnosis of an ovarian ectopic pregnancy. Examinations were personally conducted by a physician who was either a radiologist-obstetrician or an obstetrician-maternal-fetal medicine specialist. RESULTS: Six cases were identified in the 13-year period studied. Menstrual ages ranged from 6 to 9 2/7 weeks. Most (5/6) patients had abdominal pain, with 3 demonstrating it before or at 7 weeks gestation. A wide echogenic ring with an internal echolucent area was seen in 5 of 6 patients; 1 of these also contained a yolk sac, and in another, fetal heart motion could be seen. The echogenic ring seemed to be on the surface of the ovary or within the substance of the ovary in all 5 patients. The echogenicity of the ring was greater than that of the ovary in the 5 patients in whom it was identified. At surgery, the ovarian pregnancies had the appearance of a hemorrhagic ovarian cyst in all 6 patients. In the patient in whom no echogenic ring was seen the pregnancy had ruptured. All 6 cases were biopsy proven. CONCLUSION: Ovarian pregnancies usually appeared on or within the ovary as a cyst with a wide echogenic outside ring. A yolk sac or embryo was less commonly seen. The appearance of the contents lagged in comparison with the gestational age. Early abdominal pain was common.

Adult↗
PubMed2005

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.

Female↗
PubMed2005

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE: The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas. METHODS: A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed. RESULTS: Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures. CONCLUSIONS: Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Clinical Trials as Topic↗
PubMed2005

Inversion mode: a new volume analysis tool for 3-dimensional ultrasonography.

OBJECTIVES: The main goal was to introduce the inversion mode as a new image analysis tool for the examination of fluid-filled structures using 3-dimensional ultrasonography during pregnancy. METHODS: Three-dimensional ultrasonography was performed on fetuses having fluid collections of noncardiac origin. Threshold adjustment was used to visually assign full transparency to voxels that were associated with fluid. A new postprocessing tool, called the inversion mode, was activated to transform this region of interest into opaque voxels. The morphologic appearance of fluid collections and their anatomic relationship to other organs were shown in this manner. RESULTS: Diagnostic features were shown by this technique in several fetuses with problems that included pleural effusion, duodenal atresia, urinary tract abnormalities, and hydrocephaly. Furthermore, the inversion mode also permitted surface reconstruction of an irregular pleural effusion that had close resemblance to results with the Virtual Organ Computer-Aided Analysis rotational slice technique. Acoustic shadowing was also documented as a potential technical limitation of this method. CONCLUSIONS: The inversion mode can display scattered or contiguous fluid-filled structures in ways that can be very difficult or impossible to accurately characterize with conventional ultrasonography. It may be particularly helpful for the evaluation of multiple fluid-filled cysts or irregular fluid collections in the fetus.

Female↗
PubMed2005

A new approach to fetal echocardiography: digital casts of the fetal cardiac chambers and great vessels for detection of congenital heart disease.

OBJECTIVE: The purpose of this study was to describe a method of 4-dimensional (4D) reconstruction of the cardiac chambers and outflow tracts using a combination of spatiotemporal image correlation, "inversion mode," and "B-flow" imaging. METHODS: Spatiotemporal image correlation and the inversion mode were used in the examination of the volume data sets of 23 fetuses with congenital heart anomalies. A subset was also examined with B-flow imaging using the gradient light algorithm. Digital reconstructions from abnormal hearts were compared with a library obtained from fetuses without abnormalities. RESULTS: Rendered images of the 4-chamber view using the inversion mode were characterized by: (1) echogenic chambers; (2) sharp delineation of chamber contours when compared with 2-dimensional (2D) images; and (3) distinct display of the myocardium, interventricular septum, interatrial septum, and mitral and tricuspid valves as anechoic structures. Ventricular septal defects, abnormal differential insertion of the atrioventricular valves, and valve atresia were well visualized with the inversion mode. The application of inversion mode or B-flow imaging to 4D rendering of the outflow tracts resulted in "digital casts" displaying the spatial relationships between the outflow tracts as well as the connections between the great arteries and ventricular chambers. The spatial relationships and communications among cardiac structures cannot be visualized with conventional 2D ultrasonography. CONCLUSIONS: The application of spatiotemporal image correlation, inversion mode, and B-flow imaging generates information about the anatomy and pathologic characteristics of the fetal heart (digital casts) that cannot be obtained with 2D fetal echocardiography. We propose that these modalities enhance the information provided by ultrasonographic interrogation of the fetal heart and will improve prenatal diagnosis.

Echocardiography, Four-Dimensional↗
PubMed2005

Prenatal diagnosis of herniated Dandy-Walker cysts.

OBJECTIVE: The purpose of this series is to describe the prenatal diagnosis and pregnancy outcome of fetuses affected with Dandy-Walker malformation in which a posterior cyst herniated through a bony defect of the occipital skull, foramen magnum, or both. METHODS: Two- and 3-dimensional sonography were used to examine 2 fetuses with poorly delineated cerebellar structures and a large posterior cystic neck mass. Fetal magnetic resonance imaging (MRI) was added to this evaluation as a complementary diagnostic modality. RESULTS: Three-dimensional sonography helped characterize the precise site of cyst herniation through the occipital skull or foramen magnum. Fetal MRI confirmed the sonographic findings. Neonatal MRI studies identified heterotopic gray matter as evidence of a neuronal migration disorder in both fetuses. The second fetus also had agenesis of the corpus callosum. Retrospective review of the fetal MRI (25.9 weeks' menstrual age) and 3-dimensional sonographic (18.7 weeks' menstrual age) studies confirmed ventricular wall nodularity involving the occipital horns of the second fetus. CONCLUSIONS: The antenatal detection of a large posterior cystic neck mass and a poorly defined or nonvisualized cerebellar vermis suggest Dandy-Walker malformation with a herniated cyst. Three-dimensional sonography and fetal MRI are important adjunctive methods that can be used to evaluate the herniation site and a possible neuronal migrational disorder.

Adult↗
PubMed2005

The fetal arm: individualized growth assessment in normal pregnancies.

OBJECTIVE: The goals were to introduce fractional arm volume (AVol) as a new soft tissue parameter of fetal growth assessment and to develop individualized growth standards, based on Rossavik models, for AVol, midarm circumference (ArmC), and humeral diaphysis length (HDL). METHODS: A prospective longitudinal study of 22 fetuses was conducted using 2- and 3-dimensional sonography. Three new growth parameters (HDL, ArmC, and AVol) were used to establish individualized standards for arm growth with the use of Rossavik functions [P=c(t)k (+) s(t), where P is the anatomic parameter; c, k, and s are model coefficients; and t is the time variable]. Second-trimester models were specified from the linear slopes of growth curves before approximately 28.0 menstrual weeks. For a given fetus, normal third-trimester trajectories were predicted for each parameter. Observed and predicted measurements were compared by percent deviations. RESULTS: Rossavik functions fit all parameter trajectories extremely well (R(2)=95.7%-99.4%). By fixing coefficients k at their mean values, their respective fits did not change, and the variabilities of both coefficients c and s were reduced. Coefficient c was also significantly related to second-trimester slope, as was s to c, for all 3 parameters (R(2)=97.7%-98.7%; P<.0001). Mean percent deviations between observed and predicted third-trimester HDL, ArmC, and AVol measurements were -0.1% +/- 2.9%, 0.5% +/- 4.6%, and 0.4% +/- 8.5%, respectively. CONCLUSIONS: Individualized growth assessment, using HDL and ArmC, can accurately predict normal arm growth during the third trimester of pregnancy. AVol may also allow earlier detection and improved monitoring of soft tissue abnormalities that can occur in fetuses with growth disturbances.

Arm↗
PubMed2004

Sonographic detection of placenta accreta in the second and third trimesters of pregnancy.

OBJECTIVE: The purpose of this study was to determine whether ultrasonography can detect placenta accreta reliably in at-risk patients. STUDY DESIGN: All patients with a previous cesarean delivery and an anterior placenta or placenta previa were evaluated prospectively at each visit for sonographic signs of placenta accreta (interruption of the posterior bladder wall-uterine interface, absence of the retroplacental clear zone, and placental lacunae). RESULTS: This evaluation involved 2002 patients over a 12-year period. Of the 14 patients with a confirmed diagnosis of placenta accreta who had ultrasound examinations between 15 and 20 weeks of gestation, the diagnosis was suspected strongly in 86% of the patients (12/14 patients). There were 18 false-positive cases (54.5%; 18/33 patients), most of which were due to a lack of visualization of the echolucent area between the placenta and the myometrium (obliteration of the 'clear space') during the third trimester. The presence of multiple linear irregular vascular spaces within the placenta (placental lacunae) was the diagnostic sign with the highest positive predictive value for placenta accreta. CONCLUSION: Placenta accreta can be detected as early as 15 to 20 weeks of gestation in most at-risk patients by visualization of irregular vascular spaces within the placenta (placental lacunae). Obliteration of the retroplacental 'clear space' is not a reliable diagnostic sign for placenta accreta.

Female↗
PubMed2004

Fetal ultrasound training for obstetrics and gynecology residents.

OBJECTIVE: To assess the present state of fetal ultrasound training in the United States from the perspective of obstetrics and gynecology ultrasound program directors and residents. METHODS: One hundred thirty-six ultrasound program directors from 254 accredited obstetrics and gynecology residency programs completed a web-based survey regarding obstetric ultrasound training for residents. Questions were presented in yes-or-no, ranking, short-answer, and open-comment formats that examined general teaching environment and curriculum content. These results were compared with a mandatory fetal ultrasound training survey that was independently administered to 4,666 obstetrics and gynecology residents during the 2003 Council on Resident Education in Obstetrics and Gynecology (CREOG) In-Training Examination. Friedman one-way analysis of variance was used to compare ranked nonparametric data with the Dunn posttest. Statistical significance was taken at the P <.05 level. RESULTS: Fifty-four percent of accredited obstetrics and gynecology residencies responded to the survey of ultrasound directors from November 2000 to April 2003. Nearly all responding directors were obstetrician-gynecologists, many of whom had subspecialty training in maternal-fetal medicine. Full-time faculty and sonographers were the most important individuals contributing to ultrasound training for obstetrics and gynecology residents. Hands-on scanning and observation were the most significant educational activities for ultrasound training. Ultrasound program directors generally rated the overall preparedness of residents as ranging from adequate to excellent. The most important learning obstacles were limited curriculum and faculty time. Most programs evaluated competency by direct observation of scanning skills. According to the CREOG survey, only 16.3% of residents indicated that the performance and interpretation of fetal ultrasound examinations were mandatory program requirements. Nearly two thirds of residents believed that their training would be adequate by the time of graduation. Only 18.4% of residents, however, were planning to perform or interpret fetal ultrasound scans in clinical practice. CONCLUSION: Fetal ultrasound training for obstetrics and gynecology residents is perceived by most ultrasound program directors and residents to be adequate. Future development of standardized guidelines and competency assessment tools should consider that approximately one fifth of obstetrics and gynecology residents are currently planning to use this diagnostic modality in clinical practice. LEVEL OF EVIDENCE: II-2

Clinical Competence↗
PubMed2004

The use of the minimum projection mode in 4-dimensional examination of the fetal heart with spatiotemporal image correlation.

OBJECTIVE: The minimum projection mode (MPM) is a rendering algorithm available in some 3- and 4-dimensional ultrasonography systems that, in 1 image, allows the visualization of vessels and cystic anatomic structures located in different scanning planes. The objective of this study was to compare the information displayed in images obtained with the MPM with their corresponding 2-dimensional ultrasonographic images from fetuses with and without structural heart defects. METHODS: Thirty-two volume data sets acquired with the spatiotemporal image correlation technique from fetuses with (n = 15) and without (n = 17) structural heart defects were analyzed. Rendered images of the upper abdomen, 4-chamber view, and 3-vessel view were compared with the corresponding 2-dimensional images. Two independent observers with experience in fetal echocardiography reviewed these volume data sets using the MPM. The visualization rate of specific anatomic structures seen from a transverse sweep of the heart was recorded for each observer, and the interobserver agreement was assessed by statistical indices of agreement (kappa statistic). RESULTS: Images obtained by the MPM displayed more vascular structures than those of corresponding 2-dimensional images at the level of the 3-vessel view. For conotruncal anomalies, the minimum mode projected the aorta and pulmonary arteries in 1 single plane, facilitating the understanding of their spatial relationships. The interobserver agreement score was moderate to "almost perfect" for assessment of most anatomic structures in the upper abdomen, 4-chamber view, and 3-vessel view sections. However, interobserver agreement ranged from fair to poor for visualization of the left outflow tract, atrial septum, and flap of the foramen ovale. CONCLUSIONS: The MPM is an alternative rendering modality that facilitates visualization of normal and abnormal vascular connections to the fetal heart at the level of the 3-vessel view. This technique may be useful in prenatal diagnosis of conotruncal anomalies and in assessment of the spatial relationships of abnormal vascular connections in the upper mediastinum.

Algorithms↗
PubMed2004

Phenotypic characteristics of absent and hypoplastic nasal bones in fetuses with Down syndrome: description by 3-dimensional ultrasonography and clinical significance.

OBJECTIVE: To determine the frequency and clinical significance of bilateral and unilateral hypoplastic nasal bones for the detection of Down syndrome by 3-dimensional ultrasonography. METHODS: Thirty-seven volumes of the fetal skull from fetuses with Down syndrome and 37 from fetuses without abnormalities were analyzed by 1 investigator blinded to fetal karyotype. The maximum intensity projection algorithm was used to reconstruct nasal bones. Ossification patterns were identified in anteroposterior and profile views. Sensitivity, false-positive rates (FPRs), and likelihood ratios (LRs) for detection of Down syndrome were calculated. RESULTS: After exclusions (coronal acquisition [n = 11], hand in front of the face [n = 4], poor imaging [n = 2], incomplete follow-up [n = 2], and anomalies detected after delivery [n = 2]), 53 volumes were analyzed (26 fetuses with Down syndrome and 27 without abnormalities; median gestational age, 21 6/7 weeks [interquartile range, 19 6/7-25 2/7 weeks]). Rendered profile views revealed absent nasal bones in 18.9% (10 of 53) of the fetuses, and, among these, 90% (9 of 10) had Down syndrome (sensitivity, 34.6% [9 of 26]; FPR, 3.7% [1 of 27]; LR, 9.3 [95% confidence interval (CI), 1.3-68.7]). Three ossification patterns were identified in anteroposterior views: (1) normally developed, (2) delayed ossification, and (3) absent nasal bones. Sensitivity, FPR, and LR of absent nasal bones for detecting Down syndrome were 34.6% (9 of 26), 3.7% (1 of 27), and 9.0 (95% CI, 1.3-68.7), respectively. Sensitivity, FPR, and LR of delayed ossification for detecting Down syndrome were 42.3% (11 of 26), 22% (6 of 27), and 1.83 (95% CI, 0.8-4.4). CONCLUSIONS: Absence of nasal bones is associated with the highest risk of Down syndrome. Delayed ossification is associated with a lower risk of Down syndrome than absent nasal bones. These ossification patterns may be indistinguishable on 2-dimensional ultrasonography.

Down Syndrome↗