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Biomedical subjects

J P Bernard

Publications and source records attributed to J P Bernard.

At least 19 recordsLinked to original sources
PubMed2006

Feasibility and reproducibility of an image-scoring method for quality control of fetal biometry in the second trimester.

OBJECTIVES: The need for training programs and certification processes in fetal ultrasound has become obvious. The purpose of this study was to evaluate the feasibility of a score-based quality control system for fetal biometry in the second trimester. METHODS: Standard measurements of biparietal diameter and head circumference, abdominal circumference, and femur length at 20-24 weeks had been made by four operators using the same ultrasound machine. Twenty-five of each of the cephalic, abdominal and femoral images with the calipers in place were selected arbitrarily from each operator's ultrasound database and anonymized. These 300 images were analyzed by three experienced reviewers blinded to the operator's identity. Each image was first evaluated subjectively and then scored according to six criteria for abdominal and cephalic measurements and four criteria for femur length making a six-point score for abdominal and cephalic biometry and a four-point score for femur length. For subjective evaluation, inter-reviewer differences were analyzed using percentage agreement and adjusted kappa. For objective evaluation, a difference in scoring of one point or less among reviewers was considered good agreement. Intrareviewer variability was assessed using 40 images of each type of examination selected arbitrarily. RESULTS: The distribution of scores was similar between reviewers. One operator obtained significantly lower scores whereas the other three had good and comparable results. There was no statistical difference in the mean score attributed by each reviewer and agreement was good in 84-90% of the cases. Intrareviewer agreement was good in 90-100% of the cases, with similar scores for each reviewer. CONCLUSION: A quality control policy based on image scoring is feasible and allows for fair to good inter- and intrareviewer reproducibility. The potential contribution of this approach to assess the quality of routine ultrasound examinations should be tested on a larger scale.

Abdomen↗
PubMed2005

First-trimester screening for fetal triploidy at 11 to 14 weeks: a role for fetal biometry.

OBJECTIVE: Intrauterine growth restriction in triploidy has been reported as early as in the first trimester. This study was undertaken to evaluate the ability of first-trimester crown rump length (CRL)-based charts to detect triploid fetuses. MATERIAL AND METHODS: Analysis of fetal biometry in cases of triploidy diagnosed in the first trimester over the last three years. Biometry for abdominal circumference (AC), head circumference (HC) and biparietal diameter (BPD) was analyzed in relation to both gestational age (GA)-based charts and to CRL-based charts. RESULTS: Five cases of fetal triploidy were diagnosed at 11 to 14 weeks. Screening based on nuchal translucency (NT) and maternal age showed a risk > 1/300 in only one of the 5 cases of triploid fetus. In all of these five cases, CRL-based biometry was grossly abnormal, although it was abnormal in only two of these five cases in relation to GA-based charts. CONCLUSION: First-trimester CRL-based biometry charts seem to reflect early asymmetrical growth delay in triploidy more accurately than GA-based charts. CRL-based biometry is likely to improve the early detection of triploid pregnancies without leading to dating error.

Abdomen↗
PubMed2005

The impact of choice of reference charts and equations on the assessment of fetal biometry.

OBJECTIVES: The assessment of fetal biometry is usually based on the comparison of measured values with predicted values derived from reference charts or equations in a normal population. This study was undertaken to assess the impact of the choice of reference charts and to develop a Z-score-based tool that could help sonographers to choose the reference charts that best fit their practice. METHODS: Fetal biparietal diameter, head circumference, abdominal circumference and femur diaphysis length measurements were made at 20-24 and 30-34 weeks' gestation by four experienced sonographers. All measurements were transformed into Z-scores calculated according to three prediction equations (Snijders and Nicolaides, 1994; Chitty et al., 1994 and Kurmanavicius et al., 1999). Distributions of Z-scores were compared to the expected standard normal distribution based on mean, SD and Kolmogorov-Smirnov test. Simulations were made to assess sensitivity (Se), specificity (Sp) and Youden's index (Se + Sp - 1) of each reference equation, reflecting their ability to identify fetuses with abnormal biometry in our population. The reference that best fitted our practice was determined based on these results. RESULTS: The Z-scores of all biometric parameters were significantly different (P < 0.001) when using any of the three reference equations, and none of the Z-score distributions could be considered similar to the standard normal distribution. The number of measurements that would be considered as abnormal according to these references ranged from 2.6% to 23.6%. Se and Sp ranged from 39.59% to 67.12% and 90.14% to 99.69%, respectively. CONCLUSION: Assessment of fetal biometry is largely dependent on the choice of reference charts. We suggest that the choice of reference charts for fetal biometry could be controlled using Z-scores in each institution and that this could be the first step towards any quality assessment policy. The method we describe for the choice of the most appropriate fetal biometry reference chart might be used for all size charts.

Biometry↗
PubMed2005

Growth discrepancy in twins in the first trimester of pregnancy.

OBJECTIVE: The prevalence and significance of intertwin growth discrepancy in the first trimester of pregnancy are controversial. The aim of this study was to refine the incidence and outcome of this discrepancy in relation to dating of the pregnancy and other biometric parameters. METHODS: This prospective study of twin pregnancies initially evaluated at 11-14 weeks' gestation was conducted between 2001 and 2004. Differences in crown-rump length (CRL) and estimated gestational age (GA) were calculated for each twin pair and their distribution was analyzed according to chorionicity and mode of conception (spontaneous or following assisted reproductive technologies). CRL-based GA and actual GA were compared. Other biometric parameters were also compared for each twin pair. The distribution of discrepancies was analyzed according to pregnancy outcome. RESULTS: A total of 182 twin pregnancies was included. The mean+/-SD discrepancy in CRL was 3.4+/-3.18 mm or 5.1+/-4.69% and the 95th centile was 9.8 mm or 14.3%. There was no influence of chorionicity (P=0.44), mode of conception (P=0.18) and no relation with outcome (P=0.54). In conceptions resulting from assisted technology, the measured CRL of the smaller twin was closer to the actual GA. Cephalic and abdominal biometric measurements were significantly greater in the twin with the smaller CRL (P<0.05). The two cases with a discrepancy>15 mm were affected by trisomy 18 and triploidy, respectively. CONCLUSIONS: CRL discrepancy in twin pregnancies in the first trimester is a frequent finding. Discrepancy>95th centile indicates major growth delay of one twin, which could indicate the presence of aneuploidy. For milder degrees of discordance the CRL of the smaller fetus is a more accurate estimate of the actual GA.

Adult↗
PubMed2005

Analysis of Z-score distribution for the quality control of fetal ultrasound measurements at 20-24 weeks.

OBJECTIVES: To develop and evaluate the feasibility of Z-score distribution-based quality assessment for fetal biometry at 20-24 gestational weeks. METHODS: Four sonographers measured fetal biparietal diameter, head circumference, abdominal circumference and femur length in unselected pregnancies undergoing routine sonography at 20-24 weeks in our center between June 2001 and January 2004. All measurements were transformed into Z-scores. Distributions of Z-scores were compared with the expected standard normal distribution based on mean, SD and the Kolmogorov-Smirnov test. Modelling was performed to assess the sensitivity, specificity and Youden's index (sensitivity + specificity - 1) of each sonographer, reflecting their ability to detect fetuses with abnormal biometry in our population. RESULTS: A total of 5241 ultrasound examinations were included. None of the Z-score distributions could be considered similar to the standard normal distribution: means of Z-scores ranged from -0.604 to 0.73 and the SD ranged from 0.726 to 0.896. Sensitivity and specificity ranged from 25.31% to 68.67% and 93.44% to 100%, respectively; Youden's index ranged from 0.25 to 0.69. CONCLUSION: Analysis of Z-score distribution can be used to assess the quality of fetal measurements. Several indices can be extracted from this analysis in order to improve quality assessment of fetal biometry measured by ultrasound.

Abdomen↗
PubMed2005

Predicting late-onset growth abnormalities using growth velocity between trimesters.

OBJECTIVES: To determine whether growth velocity parameters derived from routine prenatal ultrasound measurements at first, second and third trimester can identify normal growth at term as well as late-onset growth abnormalities. MATERIAL AND METHODS: Longitudinal study of fetal growth in normal singleton pregnancies with three normal ultrasound examinations and delivered at term. Fetuses were classified into 3 groups (<10th percentile, 10-90th percentile, >90th percentile) based on birth weight. Multiple regression on birth weight classification was used to build up a prediction equation of fetal growth potential (FGP) based on fetal biometry and fetal growth velocity parameters between ultrasound examinations. Best cut-off value for FGP predicting growth restriction and macrosomia were defined. RESULTS: 356 pregnancies were included. Fetal biometry growth velocities between examinations were calculated for all measurements. Using best cut-off values, the estimated sensitivity, specificity and odds ratio were: 60% [44;74], 91% [89;92] and 14.55 [6.30;33.98] and 53% [36;69], 89% [88;91] and 10 [4.27;23.49] for the prediction of growth restriction and macrosomia, respectively. DISCUSSION: Fetal growth potential can be derived and calculated from standard ultrasound measurements. It can improve identification of these fetuses at risk for late-onset growth abnormalities and their related morbidity.

Adolescent↗
PubMed2004

Etched implants: a comparative surface analysis of four implant systems.

Surface texturing by acid etching has recently become popular among dental implant manufacturers. The aim of this study was to compare the surface topography of four implant systems and to check the reproducibility of the industrial process of each implant system. Three implants per system have been selected from three distinct batches. They were observed under a scanning electron microscope (SEM), and roughness was determined with a contact profilometer by measuring five height-descriptive parameters (Ra, Rq, Rz(ISO), Rt, and Rsk, a texture parameter Sm, and a hybrid parameter RDeltaq. The analysis showed that each implant system displayed a distinct surface topography that could not be mistaken. When sandblasting was performed prior to etching, surface topography was a combination of macro- and microroughness. The roughness and the amount of remaining sand varied among the batches, showing that the industrial process is not fully developed. Deviation from the released technical information was found for two out of four implant manufacturers. Based on the available biological and clinical data on textured surfaces, it is suggested that it is bone interlocking at the interface that maintains the biological properties of textured surfaces, rather than a strong implant fixation per se.

Dental Implants↗
PubMed2004

Biological properties of acid etched titanium implants: effect of sandblasting on bone anchorage.

The SLA (sandblasted with large grit and acid etched) surface is a textured surface that has been documented to lead to a rapid and strong implant fixation. The purpose of the present study was to determine the contribution of sandblasting in addition to etching to implant anchorage. It was also aimed to determine if the pits carved during etching alone have a bone-interlocking capacity that leads to microanchorage between the implant and bone. SLA implants and machined-and-acid-etched (MA) implants were placed in the maxilla of Land Race pigs. After 10 weeks of healing, they were reverse torqued. The reverse torque of the SLA and MA implants was 157.29 +/- 38.04 N cm and 105.33 +/- 25.12 N cm, respectively. Sandblasting increased bone anchorage by 49.3%; the difference was statistically significant (p =.028). Bone was found attached to both surfaces; bone ingrowth was found in the pits of both surfaces. It is suggested that the two surfaces are able to generate bone interlocking and mechanical coupling at the interface. When finite-element modeling is performed with these surfaces, it is suggested that the bound mode be used instead of the slip mode.

Bone and Bones↗
PubMed2004

Long-term vertical changes of the anterior maxillary teeth adjacent to single implants in young and mature adults. A retrospective study.

AIM: To evaluate the effects of the tooth eruption process on the position of teeth adjacent to implant-borne restorations in adult patients compared to patients in their late adolescence. SUBJECT AND METHODS: The sample included 28 patients divided into two groups. A "young adult" group consisting of 14 patients, aged from 15.5 to 21 years, and a "mature adult" group consisting of 14 patients, aged from 40 to 55 years. All patients presented missing anterior teeth, requiring insertion of 40 implant fixtures (16 central incisors, 12 lateral incisors, 12 canines). The implants were of the Straumann Dental Implant System, clinically and radiologically re-evaluated 1 year or more after the surgical procedure (mean interval=4.2 years). Assessment of the eruption of the adjacent teeth was performed using the implant as a stable point of reference: measurements of the different reference points were compared after implant placement and at follow-up examination. RESULTS: In the "young adult" group, all patients showed infra-occlusion of the implant-supported crowns: the vertical step measured on radiographs varied between 0.1 and 1.65 mm. In the "mature adult" group, all patients showed a vertical difference between the teeth adjacent to the implant-supported crown and the implant: the measured step ranged from 0.12 to 1.86 mm. No difference was found in the amount of vertical eruption between male and female patients, nor according to localization of the implant. CONCLUSION: Mature adults can exhibit major vertical steps after anterior restorations with osseointegrated fixtures to the same extent as adolescents or "young adult" individuals with residuous growth potential.

Adolescent↗
PubMed2003

Revisiting first-trimester fetal biometry.

INTRODUCTION: Although advances in ultrasound have facilitated the diagnosis of fetal abnormalities in the first trimester, fetal biometry at this stage of pregnancy remains underused in prenatal diagnosis. We hypothesized that charts which directly correlate measurements to crown-rump length (CRL) could be more accurate than those based on gestational age (GA) derived from CRL measurement. The aim of this study was to construct CRL-based biometric charts. METHODS: Measurements of biparietal diameter (BPD), head circumference (HC) and abdominal circumference (AC) were prospectively collected from 939 normal singleton fetuses. Charts and predictive equations were constructed from data obtained from pregnancies in which the CRL was between 45 and 84 mm and for which the outcome was normal. RESULTS: Measurements of BPD, HC and AC from 880 fetuses who met the criteria were correlated with CRL and used to construct charts and predictive equations. The standard error of estimates using CRL was significantly lower than that using GA in all cases. DISCUSSION: First-trimester growth charts and predictive equations based on CRL instead of GA are more accurate. They might have a role in quality control of first-trimester ultrasound examination and may help in the diagnosis of fetal conditions that involve early growth abnormalities.

Abdomen↗
PubMed2003

Comparison of fetal nasal bone assessment by ultrasound at 11-14 weeks and by postmortem X-ray in trisomy 21: a prospective observational study.

OBJECTIVE: To compare nasal bone assessment by ultrasound examination at 11-14 weeks' gestation and postmortem X-ray examination in fetuses with trisomy 21. METHODS: Twenty-one fetuses with trisomy 21 which had undergone sonographic examination at 11-14 weeks for measurement of nuchal translucency thickness and assessment of the nasal bones were examined by postmortem X-ray following termination of pregnancy. RESULTS: The nasal bones were absent in 11/21 (52.4%) fetuses on ultrasound examination at 11-14 weeks and in 10/21 (47.6%) fetuses on X-ray examination at 14 to 25 + 5 weeks. Ultrasound and X-ray findings were discordant in 9/21 (42.9%) cases. Eight of 11 (72.7%) fetuses with absent nasal bones on ultrasound examination had a nuchal translucency thickness > 95th centile. CONCLUSION: The high incidence of absent nasal bones in first-trimester fetuses with trisomy 21 is compatible with a developmental delay. Prior to inclusion of nasal bone assessment into risk calculation for trisomy 21, the independence of absence of nasal bones by ultrasound and increased nuchal translucency above the 95th centile at 11-14 weeks should be investigated more extensively.

Autopsy↗
PubMed2003

Intra- and interoperator variability in fetal nasal bone assessment at 11-14 weeks of gestation.

OBJECTIVES: Examination of the fetal nasal bones by ultrasound between 11 and 14 weeks of gestation has been proposed as an additional tool in the detection of trisomy 21 in a high-risk population. However the variability in the identification of fetal nasal bones by ultrasound has not yet been investigated. The aim of this study was to assess the intraobserver and interobserver reproducibility of fetal nasal bone identification by ultrasound between 11 and 14 weeks of gestation. METHODS: A total of 1040 consecutive ultrasound examinations were performed at 11-14 weeks of gestation for nuchal translucency (NT) measurement and nasal bone identification by ultrasound. A total of 657 consecutive video-loops were assessed by three experienced operators. Each operator assigned cases to one of three categories, namely present, uncertain or absent nasal bones, and the results were compared between operators. To assess the intraoperator variability each operator reviewed 100 randomly selected videos out of the 657 loops and again used the same classification. Results were compared by pairwise unweighted and weighted Kappa index to evaluate the inter- and intraoperator variability. RESULTS: Among the 1040 fetuses, there were 51 (4.9%) with an NT measurement above the 95th centile. Nasal bones were identified by ultrasound in 948, not seen in eight and impossible to assess in 84 fetuses. Four fetuses had trisomy 21 including three with absent nasal bones and increased NT and one with present nasal bones and normal NT. The Kappa and weighted Kappa values for interoperator variability between the three operators were between 0.26 and 0.37 and 0.33 and 0.44, respectively. The Kappa and weighted Kappa values for intraoperator variability were between 0.35 and 0.48 and 0.43 and 0.55, respectively. CONCLUSION: The assessment of fetal nasal bones is only fairly reproducible. Although the performance of the test in fetuses at high risk for trisomy 21 has been reported to be good, its implementation as an additional screening technique in the general population must be accompanied by teaching and quality control programs.

Down Syndrome↗
PubMed2003

Prenatal ultrasound diagnosis of fetal craniosynostosis.

OBJECTIVE: Craniosynostosis is defined as the premature closure of the calvarial sutures. The prevalence of this heterogeneous condition is 1 in 2000 and approximately 100 different forms have been described with an established genetic transmission in half of them. Prenatal diagnosis of craniosynostosis relies mainly on identification of associated anomalies and molecular analysis of fetal DNA, which is only feasible in some syndromic forms and in well-documented families. The objective of this study was to investigate the value of prenatal ultrasound examination of cranial sutures in fetuses at risk for craniosynostosis. METHODS: Forty fetuses at risk for craniosynostosis on the basis of either a family history (Group 1, n = 16) or skull deformity suspected on a first-level fetal ultrasound examination (Group 2, n = 24) were retrospectively investigated. Craniosynostosis was suspected on the basis of skull deformities when present, however the diagnosis was only made in cases where there was a loss of hypoechogenicity of the normal sutures. All infants had both clinical and radiological investigations performed postnatally. RESULTS: In Group 1, serial ultrasound examination from 12 weeks' gestation onwards led to accurate prenatal diagnosis in all 16 cases. Dysmorphism and skull deformity preceded closure of the sutures by 4 to 16 weeks. In Group 2, prenatal diagnosis was correct in 23/24 cases. There were no false-negative results in either group. CONCLUSIONS: This series questions further the uncertain genetic determinism of craniosynostosis and seems to rule out the hypothesis of a deformation sequence following primary closure of the cranial sutures. It also suggests that ultrasound examination is useful to demonstrate closure of the sutures in the third trimester of pregnancy in most affected cases.

Craniosynostoses↗
PubMed2003

The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin.

OBJECTIVE: The purpose of this study was to assess the value of the fetal middle cerebral artery peak systolic velocity in the prediction of anemia within 24 hours of the death of one monochorionic twin in twin-to-twin-transfusion syndrome and to establish the correlation between middle cerebral artery peak systolic velocity and hemoglobin concentration in fetuses who are at risk for acute anemia. STUDY DESIGN: Doppler examination of the middle cerebral artery peak systolic velocity was performed in 20 monochorionic survivors of pregnancies that were complicated by twin-to-twin-transfusion syndrome that occurred between 20 and 34 weeks of gestation. Doppler examination was performed before cordocentesis and after intrauterine transfusion when appropriate. Both hemoglobin concentration and middle cerebral artery peak systolic velocity were expressed in multiples of the median. Severe anemia was defined as hemoglobin concentration of <0.55 multiples of the median, and we used the cutoff point of 1.50 times the median values at any gestational age to calculate the sensitivity and specificity of middle cerebral artery peak systolic velocity in detecting moderate or severe anemia. RESULTS: Fetal anemia was confirmed in 10 of 20 fetuses. We performed seven intrauterine transfusions. The sensitivity and specificity of middle cerebral artery peak systolic velocity in the prediction of severe fetal anemia were of 90%, with a false-negative rate of 10%. The correlation between peak systolic velocity and hemoglobin concentration both before and after transfusion was evaluated by regression analysis and was strongly significant. CONCLUSION: In fetuses who are at risk of acute anemia, the measurement of middle cerebral artery peak systolic velocity was found to be a reliable noninvasive diagnostic tool and may be helpful in counseling and planning invasive assessment.

Acute Disease↗
PubMed2003

The use of lidocaine for fetocide in late termination of pregnancy.

OBJECTIVE: To assess the use of lidocaine (1%) to induce permanent fetal cardiac asystole for fetocide in late termination of pregnancy. DESIGN: Prospective observational study. SETTING: One tertiary referral fetal medicine unit in France. SAMPLE: Fifty patients undergoing termination of pregnancy between 20 and 36 weeks of gestation for severe abnormalities or severe maternal conditions. METHODS: Fetocide was performed by umbilical vein puncture under ultrasound guidance with injection of sufentanil (5 microg) followed by 7 to 30 mL of lidocaine (1%). MAIN OUTCOME MEASURES: Percentage of successful procedures to obtain permanent fetal cardiac asystole and maternal side effects. RESULTS: The procedure was successful in 92% of cases (46/50) with complete cessation of heart activity. The mean amount of lidocaine was 15.3 (6.5) mL. In three cases, fetocide was performed by cardiocentesis and in one case lidocaine was unsuccessful and fetocide was performed with KCl. There were no maternal side effects. CONCLUSIONS: Lidocaine is an effective drug to perform fetocide with doses below the toxic dose for the mother.

Abortifacient Agents, Steroidal↗
PubMed2002

[Hysterosonography].

Hysterosonography, which consists in the injection of some cc of saline in the uterine cavity during sonography, allows an exploration of the uterine cavity and of the endometrium. Accuracy of hysterosonography is similar to that of office hysteroscopy. Hysterosonography distinguishes normal cavities from pathologic ones, endometrial atrophy from mucosal anomalies, polyps from myomas. Conversely, endometrial biopsy is still necessary for diagnosis of hyperplasia or cancer. Hysterosonography can also be proposed for first trimester bleedings, trophoblast retention or ectopic pregnancy. In the near future it could be applied to therapeutic goals such as sonographic section of polyps.

Abortion, Habitual↗
PubMed2002

Sonographic diagnosis of spina bifida at 12 weeks: heading towards indirect signs.

Retrospective examination of ultrasound images obtained at 12 weeks of gestation in two fetuses with spina bifida demonstrated retraction of the frontal bones, resulting in an acorn-shaped head, the cerebral peduncles appearing parallel to each other. These craniocerebral signs may improve the accuracy of first-trimester diagnosis of spina bifida by sonography.

Female↗