Cell-free DNA testing of maternal blood in screening for trisomies in twin pregnancy: updated cohort study at 10-14 weeks and meta-analysis

OBJECTIVE

To expand the limited knowledge on cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13 in twin pregnancy by updating the data from The Fetal Medicine Foundation (FMF) on prospective first-trimester screening and those identified in a systematic review of the literature.

METHODS

The FMF data were derived from prospective screening for trisomies 21, 18 and 13 in twin pregnancies at 10 + 0 to 14 + 1 weeks' gestation using the Harmony® prenatal test. A search of MEDLINE, EMBASE, CENTRAL (The Cochrane Library), ClinicalTrials.gov and the International Clinical Trials Registry Platform (World Health Organization) was carried out to identify all peer-reviewed publications on clinical validation or implementation of maternal cfDNA testing for trisomies 21, 18 and 13 in twin pregnancy, irrespective of gestational age at testing, in which data on pregnancy outcome were provided for at least 85% of the study population. Meta-analysis was performed using the FMF data and data from the studies identified by the literature search. This review was registered in the PROSPERO international database for systematic reviews RESULTS: In the FMF study, cfDNA testing was carried out in 1442 twin pregnancies and a result was obtained, after first or second sampling, in 1367 (94.8%) cases. In 93.1% (1272/1367) of cases, there was prenatal or postnatal karyotyping or birth of phenotypically normal babies; 95 cases were excluded from further analysis either because the pregnancy ended in termination, miscarriage or stillbirth with no known karyotype (n = 56) or there was loss to follow-up (n = 39). In the 1272 pregnancies included in the study, there were 20 cases with trisomy 21, 10 with trisomy 18, two with trisomy 13 and 1240 without trisomy 21, 18 or 13. The cfDNA test classified correctly 19 (95.0%) of the 20 cases of trisomy 21, nine (90.0%) of the 10 cases of trisomy 18, one (50.0%) of the two cases of trisomy 13 and 1235 (99.6%) of the 1240 cases without any of the three trisomies. The literature search identified 12 relevant studies, excluding our papers because their data are included in the current study. In the combined populations of our study and the 12 studies identified by the literature search, there were 137 trisomy-21 and 7507 non-trisomy-21 twin pregnancies; the pooled weighted detection rate (DR) and false-positive rate (FPR) were 99.0% (95% CI, 92.0-99.9%) and 0.02% (95% CI, 0.001-0.43%), respectively. In the combined total of 50 cases of trisomy 18 and 6840 non-trisomy-18 pregnancies, the pooled weighted DR and FPR were 92.8% (95% CI, 77.6-98.0%) and 0.01% (95% CI, 0.00-0.44%), respectively. In the combined total of 11 cases of trisomy 13 and 6290 non-trisomy-13 pregnancies, the pooled weighted DR and FPR were 94.7% (95% CI, 9.14-99.97%) and 0.10% (95% CI, 0.03-0.39%), respectively.

CONCLUSIONS

In twin pregnancy, the reported DR of trisomy 21 by cfDNA testing is high, but lower than that in singleton pregnancy, whereas the FPR appears to be equally low. The number of cases of trisomy 18 and more so trisomy 13 was too small for accurate assessment of the predictive performance of the cfDNA test. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

New approach for estimating risk of miscarriage after chorionic villus sampling

OBJECTIVE

To estimate the risk of miscarriage associated with chorionic villus sampling (CVS).

METHODS

This was a retrospective cohort study of women attending for routine ultrasound examination at 11 + 0 to 13 + 6 weeks' gestation at one of eight fetal-medicine units in Spain, Belgium and Bulgaria, between July 2007 and June 2018. Two populations were included: (1) all singleton pregnancies undergoing first-trimester assessment at Hospital Clínico Universitario Virgen de la Arrixaca in Murcia, Spain, that did not have CVS (non-CVS group); and (2) all singleton pregnancies that underwent CVS following first-trimester assessment at one of the eight participating centers (CVS group). We excluded pregnancies diagnosed with genetic anomalies or major fetal defects before or after birth, those that resulted in termination and those that underwent amniocentesis later in pregnancy. We used propensity score (PS) matching analysis to estimate the association between CVS and miscarriage. We compared the risk of miscarriage of the CVS and non-CVS groups after PS matching (1:1 ratio). This procedure creates two comparable groups balancing the maternal and pregnancy characteristics that are associated with CVS, in a similar way to that in which randomization operates in a randomized clinical trial.

RESULTS

The study population consisted of 22 250 pregnancies in the non-CVS group and 3613 in the CVS group. The incidence of miscarriage in the CVS group (2.1%; 77/3613) was significantly higher than that in the non-CVS group (0.9% (207/22 250); P < 0.0001). The PS algorithm matched 2122 CVS with 2122 non-CVS cases, of which 40 (1.9%) and 55 (2.6%) pregnancies in the CVS and non-CVS groups, respectively, resulted in a miscarriage (odds ratio (OR), 0.72 (95% CI, 0.48-1.10); P = 0.146). We found a significant interaction between the risk of miscarriage following CVS and the risk of aneuploidy, suggesting that the effect of CVS on the risk of miscarriage differs depending on background characteristics. Specifically, when the risk of aneuploidy is low, the risk of miscarriage after CVS increases (OR, 2.87 (95% CI, 1.13-7.30)) and when the aneuploidy risk is high, the risk of miscarriage after CVS is paradoxically reduced (OR, 0.47 (95% CI, 0.28-0.76)), presumably owing to prenatal diagnosis and termination of pregnancies with major aneuploidies that would otherwise have resulted in spontaneous miscarriage. For example, in a patient in whom the risk of aneuploidy is 1 in 1000 (0.1%), the risk of miscarriage after CVS will increase to 0.3% (0.2 percentage points higher).

CONCLUSIONS

The risk of miscarriage in women undergoing CVS is about 1% higher than that in women who do not have CVS, although this excess risk is not solely attributed to the invasive procedure but, to some extent, to the demographic and pregnancy characteristics of the patients. After accounting for these risk factors and confining the analysis to low-risk pregnancies, CVS seems to increase the risk of miscarriage by about three times above the patient's background risk. Although this is a substantial increase in relative terms, in pregnancies without risk factors for miscarriage, the risk of miscarriage after CVS remains low and similar to, or slightly higher than, that in the general population. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Screening for trisomies by cfDNA testing of maternal blood in twin pregnancy: update of The Fetal Medicine Foundation results and meta-analysis

OBJECTIVES

To report on the routine clinical implementation of cell-free DNA (cfDNA) analysis of maternal blood for trisomies 21, 18 and 13 in twin pregnancy and to define the performance of the test by combining our results with those identified in a systematic review of the literature.

METHODS

The data for the prospective study were derived from screening for trisomies 21, 18 and 13 in twin pregnancies at 10 + 0 to 14 + 1 weeks' gestation. Two populations were included; first, self-referred women to the Fetal Medicine Centre in London or Brugmann University Hospital in Brussels and, second, women selected for the cfDNA test after routine first-trimester combined testing at one of two National Health Service hospitals in England. This dataset was used to determine the performance of screening for the three trisomies. Search of MEDLINE, EMBASE, CENTRAL (The Cochrane Library), ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP) was carried out to identify all peer-reviewed publications on clinical validation or implementation of maternal cfDNA testing for trisomies 21, 18 and 13 in twin pregnancy. A meta-analysis was then performed using our data and those in the studies identified by the literature search.

RESULTS

In our dataset of 997 twin pregnancies with a cfDNA result and known outcome, the test classified correctly 16 (94.1%) of the 17 cases of trisomy 21, nine (90.0%) of the 10 cases of trisomy 18, one (50.0%) of the two cases of trisomy 13 and 962 (99.4%) of the 968 cases without any of the three trisomies. The literature search identified seven relevant studies, excluding our previous papers because their data are included in the current study. In the combined populations of our study and the seven studies identified by the literature search, there were 56 trisomy-21 and 3718 non-trisomy-21 twin pregnancies; the pooled weighted detection rate (DR) and false-positive rate (FPR) were 98.2% (95% CI, 83.2-99.8%) and 0.05% (95% CI, 0.01-0.26%), respectively. In the combined total of 18 cases of trisomy 18 and 3143 non-trisomy-18 pregnancies, the pooled weighted DR and FPR were 88.9% (95% CI, 64.8-97.2%) and 0.03% (95% CI, 0.00-0.33%), respectively. For trisomy 13, there were only three affected cases and two (66.7%) of these were detected by the cfDNA test at a FPR of 0.19% (5/2569).

CONCLUSIONS

The performance of cfDNA testing for trisomy 21 in twin pregnancy is similar to that reported in singleton pregnancy and is superior to that of the first-trimester combined test or second-trimester biochemical testing. The number of cases of trisomies 18 and 13 is too small for accurate assessment of the predictive performance of the cfDNA test. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Minimally invasive fetal autopsy using ultrasound: a feasibility study

OBJECTIVES

To evaluate postmortem ultrasound (PM-US) for minimally invasive autopsy, and to demonstrate its feasibility, sensitivity and specificity, as compared with conventional autopsy, in detecting major congenital abnormalities.

METHODS

Over a 19-month study period from 1 March 2012 to 30 September 2013, we recruited from a referral hospital 88 consecutive fetuses, at 11-40 weeks' gestation, which had undergone termination, miscarriage or intrauterine fetal death. We performed PM-US using different transducers and compared the data with those from conventional autopsy. The latter was performed, according to the Societé Francaise de Foetopathologie (France) guidelines, by experienced perinatal pathologists who were blinded to the ultrasound data.

RESULTS

Complete virtual autopsy by ultrasound was possible in 95.5% of the cases. The sensitivity of PM-US for detecting brain abnormalities was 90.9% (95% CI, 58.7-99.8%) and the specificity was 87.3% (95% CI, 75.5-94.7%). In 20% of cases, a neuropathological examination was not possible due to severe maceration. The sensitivity for detection of thoracic abnormalities was 88.9% (95% CI, 65.3-98.6%) and the specificity was 92.8% (95% CI, 84.1-97.6%), and the sensitivity for detection of abdominal anomalies was 85.7% (95% CI, 57.2-98.2%) and the specificity was 94.6% (95% CI, 86.7-98.5%).

CONCLUSION

This pilot study confirms the feasibility of PM-US for virtual autopsy as early as 11 weeks' gestation. This new technique shows high sensitivity and specificity in detecting congenital structural abnormalities as compared with conventional autopsy. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Cell-free fetal DNA analysis in maternal plasma as screening test for trisomies 21, 18 and 13 in twin pregnancy

OBJECTIVES

To evaluate in twin pregnancy the utility of non-invasive prenatal testing using circulating cell-free fetal DNA (cfDNA) in screening for the three main autosomal fetal trisomies.

METHODS

cfDNA testing was offered to 492 patients with a twin pregnancy without ultrasound anomaly as a first-line screening test or after routine serum screening. Data were collected prospectively and a retrospective analysis was performed. cfDNA analysis was performed by massively parallel sequencing. The fetal-fraction threshold used for test evaluation was 8%. Regression analysis was performed to investigate the effect on the test failure rate of maternal and pregnancy characteristics, and the performance of the test was also reported.

RESULTS

cfDNA analysis was performed as a first-line test (after the first-trimester scan) in 377 patients and following serum screening in 115. Of the 420 pregnancies for which outcome was available and cfDNA screening was assessed, 78.7% were dichorionic-diamniotic. The test failed on the first attempt in 12 (2.9%) pregnancies, and regression analysis demonstrated that only maternal weight was a significant independent predictor of test failure. A result was subsequently achieved in the 10 cases for which a second sample was obtained. cfDNA analysis identified all three cases of trisomy 21 and the only case of trisomy 18. For trisomy 21, the specificity was 99.8% (95% CI, 98.7-100.0%). When considering pregnancies according to whether they were conceived spontaneously or after assisted reproductive technology, there were no significant differences in terms of maternal weight or no-result rate for cfDNA screening between these two groups.

CONCLUSIONS

In twin pregnancy without fetal ultrasound abnormality, cfDNA screening for trisomies 21, 18 and 13 had a high success rate and good performance. Therefore, in routine practice, cfDNA analysis could be considered as a first- or second-line screening test. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

[Cell-free fetal DNA analysis in maternal plasma as a screening test for trisomy 21 in twin pregnancies]

OBJECTIVES

To evaluate the performance of noninvasive prenatal testing by cell-free circulating fetal DNA in maternal blood (cfDNA) in screening for trisomies 21 in twin pregnancies.

METHODS

CfDNA was performed in 492 patients with twin pregnancies without ultrasound anomalies in the first trimester as a first-line screening test or after serum screening. Data were collected prospectively and a retrospective analysis was done. CfDNA was executed by massive parallel technique. The fetal fraction threshold for test evaluation was 8%. Regression analysis was performed to evaluate the effect of different parameters on the test failure rate. Performance of the test was also considered.

RESULTS

In 377 patients, the test was prescribed first line and in 115 after standard serum screening. Twelve tests (2.9%) have initially failed on the 420 pregnancies with available outcomes and regression analysis found only maternal weight as a significant independent factor of test failure. A second test was performed on 10 patients, all of them had an available result. cfDNA identified all 3 cases of trisomy 21. The sensitivity was 100.0% (95% CI [29.2-100.0%]) and specificity was 99.8% (95% CI [98.7-100.0%]). There was no significant difference between spontaneous pregnancies and those induced by assisted reproductive technologies (ART), in terms of fetal fraction percentage, no-call results for cfDNA screening, maternal weight, or test performance between the two groups.

CONCLUSION

In twin pregnancies without fetal ultrasound abnormalities, the performance and success rate of the cfDNA are excellent. Therefore, cfDNA could be offered in routine practice as a first-line screening test in this population.

A novel diagnostic algorithm for heparin-induced thrombocytopenia

INTRODUCTION

While diagnostic algorithm using PF4-heparin enzyme-linked immunosorbent assay (ELISA) optical density (OD), and heparin neutralization assay (HNA), or 4T score have been proposed to replace serotonin-release assay (SRA) for heparin-induced thrombocytopenia (HIT), their performance against SRA is unclear. In this study, we proposed and validated the performance of a new algorithm combining PF4-heparin ELISA optical density (OD), HNA and 4T score against SRA for HIT diagnosis.

METHODS

Heparin neutralization assays were performed on specimens submitted for HIT testing with positive PF4-heparin ELISA from December 2015 to September 2017, which were separated into a "training" and a "validation" data set. 4T scores were calculated for ELISA positive cases.

RESULTS

A total of 123 consecutive unique patient samples had positive PF4-heparin ELISA with also HNA data, SRA data, and 4T scores available. Compared to SRA, a "laboratory criteria" (ELISA OD ≥ 1.4 and HNA ≥ 70%) had a sensitivity of 88% (14/16) and specificity of 91% (42/46), and a "combined criteria" (4T score = 8, or 4T score = 6 or 7 and ELISA OD ≥ 1.0, or 4T score = 4 or 5 and ELISA OD ≥ 2.0) had a sensitivity of 75% (12/16) and specificity of 98% (45/46) in the training data set. Laboratory and combined criteria had 90% (56/62) concordance rate. Importantly, for these concordant cases, the diagnostic specificity is 100% (46/46). Based on the data, a novel diagnostic algorithm combining these 2 criteria was proposed and validated prospectively.

CONCLUSION

A novel algorithm has high diagnostic accuracy and potentially could eliminate the need for SRA testing in at least 90% patients with suspected HIT.

Prognosis of isolated congenital diaphragmatic hernia using lung-area-to-head-circumference ratio: variability across centers in a national perinatal network

OBJECTIVE

Congenital diaphragmatic hernia (CDH) is a severe anomaly. The observed-to-expected lung-area-to-head-circumference ratio (o/e-LHR) has been shown to provide a useful prediction of subsequent survival of fetuses with CDH in referral centers with expertise and a large caseload. However, the accuracy of o/e-LHR measurements in general fetal medicine units with less expertise is not well known. The aim of this study was to evaluate the capacity of o/e-LHR to provide a useful prediction of mortality of fetuses with CDH when the measurement is performed in fetal medicine units with different levels of expertise.

METHODS

Between January 2008 and November 2013, 305 live births with expectantly managed left-sided isolated CDH were recorded in the database of the French National Center for Rare Diseases (31 centers) and followed up after birth. Centers were grouped into two categories according to their mean annual CDH caseload over the study period: large centers with an average of ≥ 14 cases and smaller centers with < 14 cases per year. The relationship between o/e-LHR and 28-day and 6-month mortality was modeled using fractional polynomials and the predictive value of o/e-LHR was quantified using the area under the receiver-operating characteristics curve. Comparisons between the two center categories were carried out. Analyses were adjusted for potential confounders such as thoracic herniation of the liver and gestational age at birth and at diagnosis.

RESULTS

During the study period, two large centers managed a total of 82 CDH cases and 29 smaller centers a total of 223 CDH cases. Overall, there was a significant inverse relationship between 28-day mortality rate and o/e-LHR, which decreased from 54% when o/e-LHR was 20% to 6% when o/e-LHR was 75% (P < 0.01). When the category of center was considered, adjusted associations between o/e-LHR and 28-day mortality were significantly different (P = 0.032) between large and smaller centers. The ability to predict survival at 28 days postpartum based on o/e-LHR was better in large centers; for a specificity of 0.30, the sensitivity was 0.71 in large centers and 0.55 in smaller ones. The results were similar for 6-month mortality.

CONCLUSIONS

Our results show that o/e-LHR measured on two-dimensional ultrasound is a good indicator of neonatal prognosis in cases of CDH that may be used even in fetal medicine centers with a small caseload. However, our results also suggest that LHR measurement may be difficult to perform correctly. Therefore, appropriate training should be offered to professionals. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Accuracy of competing-risks model in screening for pre-eclampsia by maternal factors and biomarkers at 11-13 weeks' gestation

OBJECTIVE

To examine the diagnostic accuracy of a previously developed model for prediction of pre-eclampsia (PE) by a combination of maternal factors and biomarkers at 11-13 weeks' gestation.

METHODS

This was a prospective first-trimester multicenter study of screening for PE in 8775 singleton pregnancies. A previously published algorithm was used for the calculation of patient-specific risk of PE in each individual. The detection rates (DRs) and false-positive rates (FPRs) for delivery with PE < 32, < 37 and ≥ 37 weeks were estimated and compared with those for the dataset used for development of the algorithm.

RESULTS

In the study population, 239 (2.7%) cases developed PE, of which 17 (0.2%), 59 (0.7%) and 180 (2.1%) developed PE < 32, < 37 and ≥ 37 weeks, respectively. With combined screening by maternal factors, mean arterial pressure, uterine artery pulsatility index and serum placental growth factor, the DR was 100% (95% CI, 80-100%) for PE < 32 weeks, 75% (95% CI, 62-85%) for PE < 37 weeks and 43% (95% CI, 35-50%) for PE ≥ 37 weeks, at a 10% FPR. These DRs were similar to the estimated rates for the dataset used for development of the model: 89% (95% CI, 79-96%) for PE < 32 weeks, 75% (95% CI, 70-80%) for PE < 37 weeks and 47% (95% CI, 44-51%) for PE ≥ 37 weeks.

CONCLUSION

Assessment of a combination of maternal factors and biomarkers at 11-13 weeks provides effective first-trimester screening for preterm PE. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Use of spatiotemporal image correlation at 11-14 weeks' gestation

OBJECTIVE

To assess prospectively the use of four-dimensional (4D) spatiotemporal image correlation (STIC) in the evaluation of the fetal heart at 11-14 weeks' gestation.

METHODS

The study involved offline analysis of 4D-STIC volumes of the fetal heart acquired at 11-14 weeks' gestation in a population at high risk for congenital heart disease (CHD). Regression analysis was used to investigate the effect of gestational age, maternal body mass index, quality of the 4D-STIC volume, use of a transvaginal vs transabdominal probe and use of color Doppler ultrasonography on the ability to visualize separately different heart structures. The accuracy in diagnosing CHD based on early fetal echocardiography (EFE) using 4D-STIC vs conventional two-dimensional (2D) ultrasound was also evaluated.

RESULTS

One hundred and thirty-nine fetuses with a total of 243 STIC volumes were included in this study. Regression analysis showed that the ability to visualize different heart structures was correlated with the quality of the acquired 4D-STIC volumes. Independently, the use of a transvaginal approach improved visualization of the four-chamber view, and the use of Doppler improved visualization of the outflow tracts, aortic arch and interventricular septum. Follow-up was available in 121 of the 139 fetuses, of which 27 had a confirmed CHD. A diagnosis based on EFE using 4D-STIC was possible in 130 (93.5%) of the 139 fetuses. Accuracy in diagnosing CHD using 4D-STIC was 88.7%, and the results of 45% of the cases were fully concordant with those of 2D ultrasound or the final follow-up diagnosis. EFE using 2D ultrasound was possible in all fetuses, and accuracy in diagnosing CHD was 94.2%. Five of the seven false-positive or false-negative cases were minor CHD.

CONCLUSIONS

In fetuses at 11-14 weeks' gestation, the heart can be evaluated offline using 4D-STIC in a large number of cases, and this evaluation is more successful the higher the quality of the acquired volume. 2D ultrasound remains superior to 4D-STIC at 11-14 weeks, unless volumes of good to high quality can be obtained.

Predictors of neonatal morbidity in fetuses with severe isolated congenital diaphragmatic hernia undergoing fetoscopic tracheal occlusion

OBJECTIVES

To investigate neonatal morbidity in fetuses with severe congenital diaphragmatic hernia (CDH) treated with fetoscopic endoluminal tracheal occlusion (FETO) and compare it with historical controls with less severe forms of CDH that were managed expectantly.

METHODS

This was a prospective, multicenter study on neonatal outcomes and prenatal predictors in 90 FETO survivors (78 left-sided, 12 right) and 41 controls from the antenatal CDH registry with either severe or moderate hypoplasia who were managed expectantly. We also investigated early neonatal morbidity indicators, including the need for patch repair, duration of mechanical ventilation and supplemental oxygen, age at full enteral feeding and incidence of pulmonary hypertension.

RESULTS

Gestational age at delivery was predictive of duration of assisted ventilation (P = 0.046), days on supplemental oxygen (P = 0.019) and age at full enteral feeding (P = 0.020). When delivery took place after 34 weeks' gestation, neonatal morbidity of FETO cases was comparable with that of expectantly managed cases with moderate hypoplasia.

CONCLUSIONS

Fetal intervention for severe CDH is associated with neonatal morbidity that is comparable with that of an expectantly managed group with less severe disease.

Biomechanical effects of hardware configuration after union of proximal femoral and shaft fractures

OBJECTIVES

The use of two implants to manage concomitant ipsilateral femoral shaft and proximal femoral fractures has been indicated, but no studies address the relationship of dynamic hip screw (DHS) side plate screws and the intramedullary nail where failure might occur after union. This study compares different implant configurations in order to investigate bridging the gap between the distal DHS and tip of the intramedullary nail.

METHODS

A total of 29 left synthetic femora were tested in three groups: 1) gapped short nail (GSN); 2) unicortical short nail (USN), differing from GSN by the use of two unicortical bridging screws; and 3) bicortical long nail (BLN), with two angled bicortical and one unicortical bridging screws. With these findings, five matched-pairs of cadaveric femora were tested in two groups: 1) unicortical long nail (ULN), with a longer nail than USN and three bridging unicortical screws; and 2) BLN. Specimens were axially loaded to 22.7 kg (50 lb), and internally rotated 90°/sec until failure.

RESULTS

For synthetic femora, a difference was detected between GSN and BLN in energy to failure (p = 0.04) and torque at failure (p = 0.02), but not between USN and other groups for energy to failure (vs GSN, p = 0.71; vs BLN, p = 0.19) and torque at failure (vs GSN, p = 0.55; vs BLN, p = 0.15). For cadaveric femora, ULN and BLN performed similarly because of the improvement provided by the bridging screws.

CONCLUSIONS

Our study shows that bicortical angled screws in the DHS side plate are superior to no screws at all in this model and loading scenario, and suggests that adding unicortical screws to a gapped construct is probably beneficial.

Does three-dimensional power Doppler ultrasound predict histopathological findings of uterine fibroids? A preliminary study

OBJECTIVES

To compare three-dimensional (3D) power Doppler sonographic characteristics of fibroids with histopathological parameters.

METHODS

We evaluated sonographically 73 fibroids before myomectomy or hysterectomy. For each, the total fibroid volume, a shell of 3 mm and a 1-cm(3) spherical sample from the most vascularized area on subjective assessment were captured. 3D power Doppler vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were generated in the acquired volumes. The degree of cellularity, ischemic necrosis and fibrosclerosis, as well as CD31 and Ki-67 staining for vascular density and proliferation index, respectively, were estimated using the surgical sample. Pathological data were considered as dependent variables and ultrasound data as independent variables in multivariable logistic regression models including patients' characteristics.

RESULTS

A high histological 'cellular activity score', combining hypercellularity, a fibrosclerosis rate < 25% and positive Ki-67 staining, was statistically related in multivariate analyses to high 3D power Doppler VI in spherical samples (odds ratio (OR), 1.1 (95% CI, 1.0-1.3), P < 0.05) and VFI (OR, 1.3 (95% CI, 1.0-1.8), P < 0.05). Positive CD31 staining was statistically related to high 3D power Doppler VI in spherical samples (OR, 1.1 (95% CI, 1.0-1.3), P < 0.05). In contrast, ischemic necrosis was statistically related to low 3D power Doppler VI in the total volume (OR, 0.6 (95% CI, 0.4-1.0), P < 0.05) and VFI (OR, 0.4 (95% CI, 0.1-1.1), P < 0.05).

CONCLUSION

Vascular density, ischemic necrosis and histological cellular activity score are statistically significantly associated with some 3D power Doppler indices.

Effect of assay specificity on the association of urine 11-dehydro thromboxane B2 determination with cardiovascular risk

BACKGROUND

Elevated urine 11-dehydro TXB(2), an indicator of persistent thromboxane generation in aspirin-treated patients, correlates with adverse cardiovascular outcome and has recently been identified as an independent risk factor for vein graft thrombosis after cardiac bypass surgery in the Reduction in Graft Occlusion Rates (RIGOR) study. The polyclonal antibody-based ELISA used to measure 11-dehydro TXB(2) in these previous studies is no longer clinically available and has been supplanted by a Food and Drug Administration (FDA)-cleared second-generation monoclonal antibody-based ELISA.

OBJECTIVES

To compare the laboratory and clinical performance of the first- and second-generation assays in a well-defined study population.

METHODS

11-dehydro TXB(2) was quantified in 451 urine samples from 229 Reduction in Graft Occlusion Rates (RIGOR) subjects using both ELISA. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and spiking studies were used to investigate discordant assay results. The association of 11-dehydro TXB(2) to clinical outcome was assessed for each assay using multivariate modeling.

RESULTS

Median 11-dehydro TXB(2) levels were higher by monoclonal antibody- compared with polyclonal antibody-based ELISA (856 vs. 399 pg mg(-1) creatinine, P < 0.000001), with the latter providing values similar to UPLC-MS/MS. This discrepancy was predominantly as a result of cross-reactivity of the monoclonal antibody with 11-dehydro-2,3-dinor TXB(2), a thromboxane metabolite present in a similar concentration but with a poor direct correlation with 11-dehydro TXB(2). In contrast to the first-generation ELISA, 11-dehydro TXB(2) measured by the monoclonal antibody-based ELISA failed to associate with the risk of vein graft occlusion.

CONCLUSION

Quantification of urine 11-dehydro TXB(2) by monoclonal antibody-based ELISA was confounded by interference from 11-dehydro-2,3-dinor TXB(2) which reduced the accuracy and clinical utility of this second-generation assay.

Postmortem examination of human fetal hearts at or below 20 weeks' gestation: a comparison of high-field MRI at 9.4 T with lower-field MRI magnets and stereomicroscopic autopsy

OBJECTIVES

To compare the diagnostic usefulness of high-field with low-field magnetic resonance imaging (MRI) and stereomicroscopic autopsy for examination of the heart in fetuses at or under 20 weeks' gestation.

METHODS

Prior to invasive stereomicroscopic autopsy, MRI scans at 9.4, 3.0 and 1.5 T were performed on 24 fetuses between 11 and 20 weeks' gestation, including 10 fetuses with cardiac abnormalities. The ability to visualize different heart structures was evaluated according to the different field strength MRI magnets used and gestational age at examination.

RESULTS

On 1.5- and 3.0-T MRI, only the heart situs and four-chamber view could be visualized consistently (in 75% or more of cases) when the fetus was beyond 16 weeks' gestation, but other heart structures could not be visualized for fetuses at any gestational age. In contrast, using high-field MRI at 9.4 T, the heart situs, four-chamber view and the outflow tracts could be visualized in all fetuses irrespective of gestational age. Using high-field MRI, the sensitivity for detecting an abnormality of the four-chamber view was 66.7% (95% CI, 30.1-92.1%) with a specificity of 80.0% (95% CI, 51.9-95.4%). For abnormalities of the outflow tracts, sensitivity was 75.0% (95% CI, 20.3-95.9%) and specificity 100.0% (95% CI, 83.3-100.0%). Eight fetuses out of 10 with congenital heart disease (CHD) were classified as having major CHD. High-field MRI at 9.4 T was able to identify seven out of the eight cases of major CHD.

CONCLUSION

High-field MRI at 9.4 T seems to be an acceptable alternative approach to invasive stereomicroscopic autopsy for fetuses with CHD at or below 20 weeks' gestation.

Fetal organ weight estimation by postmortem high-field magnetic resonance imaging before 20 weeks' gestation

OBJECTIVE

To ascertain whether high-field magnetic resonance imaging (MRI) allows accurate estimation of the weight of various fetal organs at postmortem before 20 weeks' gestation.

METHODS

From 23 fetuses at 9-20 weeks, following termination of pregnancy or in-utero fetal death (IUFD), 207 assorted fetal organs were evaluated by high-field MRI at 9.4 T prior to conventional autopsy. Fetal organ density was calculated by correlating volume and weight at autopsy using linear regression analysis, and this was used to estimate fetal organ weight by MRI. The relative error in MRI estimation of organ weight was calculated as follows: (|MRI weight - autopsy weight|/autopsy weight) × 100 (%). Multiple regression analysis was used to investigate the effect on the relative error of MRI organ weight estimates of gestational age at TOP or delivery following IUFD, autopsy weight, fetal organ examined, IUFD and fetal maceration.

RESULTS

Of the 207 organs evaluated, 133 (64%) were examined for fetal organ density and 155 (75%) for fetal organ weight. Fifty-two organs were excluded from our analysis; 41 of these were from fetuses with IUFD, with 39 organs macerated. In 32 cases, exclusion was due to an inability to assess the organ both on MRI and on conventional autopsy. Volume and weight at autopsy correlated significantly, following the linear equation: autopsy volume = (0.9947 × autopsy weight) - 4.7556, where autopsy volume is in mm(3) and weight is in mg (r = 0.99, P < 0.001). Overall the mean relative error in the MRI estimation of organ weight was 68%. Multiple regression analysis showed that the relative error in the MRI estimation of organ weight was significantly associated with gestational age at TOP or delivery following IUFD and fetal maceration, but not with autopsy weight, fetal organ examined or IUFD. In the subgroup of non-macerated organs and for fetuses above 14 weeks' gestation, the mean relative error in the MRI estimation of organ weight was 34%.

CONCLUSION

In fetuses before 20 weeks' gestation, noninvasive estimation of organ weight is feasible using high-field MRI, but there is a mean overestimation. Limitations of the technique occur mainly in cases of small macerated fetuses before 14 weeks' gestation.

Virtual autopsy by computed tomographic angiography of the fetal heart: a feasibility study

OBJECTIVE

To determine the feasibility of postmortem computed tomographic (pm-CT) angiography for fetal heart evaluation.

METHODS

Following termination of pregnancy (TOP) or intrauterine fetal death (IUFD) beyond 18 weeks' gestation, 33 fetuses were examined by pm-CT; in eight contrast medium was injected through the umbilical cord and in 25 contrast medium was injected directly into the heart. Logistic regression analysis was used to investigate the effect on the ability to visualize cardiac structures on pm-CT angiography of gestational age at TOP or delivery following IUFD, the time delay between fetal death and examination, the technique used for contrast-medium injection, the presence of cardiac abnormalities and whether or not there was IUFD. The diagnostic accuracy of pm-CT angiography for the evaluation of fetal cardiac structures was also evaluated.

RESULTS

Cardiac anatomy including heart situs, the four-chamber view and great vessels could be visualized on pm-CT angiography in 29 out of 33 fetuses (87.9%). Logistic regression analysis showed that the ability to visualize cardiac structures on pm-CT angiography was positively correlated only with contrast medium injected directly into the heart. Twenty-five out of the 33 fetuses underwent conventional autopsy. There were five cases with suspected major cardiac abnormality at prenatal ultrasound and one with a minor cardiac abnormality. In one of these cases, severe leakage into the pleural cavity did not allow for visualization of any heart structure on pm-CT angiography and in another invasive autopsy was declined. In two of the remaining four cases, the findings on pm-CT angiography and invasive autopsy were in agreement, while in two a ventricular septal defect was found on invasive autopsy but not on pm-CT. None of the 27 cases with normal hearts was falsely classified as abnormal using pm-CT angiography.

CONCLUSION

Pm-CT angiography by direct injection into the heart seems to be a feasible method for its evaluation. The extent to which such a technique could be used for the evaluation of congenital heart disease as an alternative to classical postmortem autopsy remains to be determined.

Acceptance, reliability and confidence of diagnosis of fetal and neonatal virtuopsy compared with conventional autopsy: a prospective study

OBJECTIVES

To compare prospectively maternal acceptance of fetal and neonatal virtuopsy with that of conventional autopsy and to determine the confidence with which magnetic resonance (MR) virtuopsy can be used to diagnose normality/abnormality of various fetal anatomical structures.

METHODS

MR and/or computed tomography virtuopsy and conventional autopsy were offered to 96 women (102 fetuses/neonates) following termination of pregnancy (TOP), intrauterine fetal death (IUFD) or neonatal death. Multivariable logistic regression analysis was used to investigate the effect on maternal acceptance of virtuopsy and/or conventional autopsy of the age of the mother, gestational age at TOP or delivery after IUFD, order of pregnancy, parity, religion, type of caregiver obtaining consent and reason for death. When parents consented to both MR virtuopsy and conventional autopsy of fetuses ≥ 20 weeks of gestation or neonates, the confidence with which MR virtuopsy could be used to diagnose normality/abnormality of various anatomical structures was determined on a scale in which conventional autopsy was considered gold standard. On autopsy we classified fetuses/neonates as having either 'normal' or 'abnormal' anatomical structures; these groups were analyzed separately. At virtuopsy, we indicated confidence of diagnosis of normality/abnormality of every anatomical structure in each of these two groups defined at autopsy, using a scale from 0 (definitely abnormal) to 100 (definitely normal).

RESULTS

Of the 96 women, 99% (n = 95) consented to virtuopsy and 61.5% (n = 59) to both conventional autopsy and virtuopsy; i.e. 36 (37.5%) consented to virtuopsy alone. Maternal acceptance of conventional autopsy was independently positively related to singleton pregnancy, non-Moslem mother, earlier gestation at TOP or delivery afer IUFD and a maternal-fetal medicine specialist obtaining consent. Thirty-three fetuses ≥ 20 weeks of gestation had both conventional autopsy and MR virtuopsy, of which 19 had a full autopsy including the brain. In fetuses with normal anatomical structures at conventional autopsy, MR virtuopsy was associated with high diagnostic confidence (scores > 80) for the brain, skeleton, thoracic organs except the heart, abdominal organs except the pancreas, ureters, bladder and genitals. In fetuses with abnormal anatomical structures at autopsy, MR virtuopsy detected the anomalies with high confidence (scores < 20) for these same anatomical structures. However, in three cases, virtuopsy diagnosed brain anomalies additional to those observed at conventional autopsy.

CONCLUSION

MR virtuopsy is accepted by nearly all mothers while conventional autopsy is accepted by about two-thirds of mothers, in whom refusal depends mainly on factors over which we have no control. Although conventional autopsy remains the gold standard, the high acceptance of virtuopsy makes it an acceptable alternative when the former is declined.

Magnetic resonance imaging in the normal fetal heart and in congenital heart disease

OBJECTIVE

To evaluate prospectively the feasibility of magnetic resonance imaging (MRI) for assessment of the fetal heart for congenital heart disease (CHD).

METHODS

This was a cross-sectional study, including 66 fetuses with a normal heart and 40 with CHD. The fetal heart was examined on MRI using axial steady-state free precession (SSFP) sequences. Regression analysis was used to investigate the effect on the ability to visualize cardiac anatomy of gestational age at examination, maternal body mass index, presence of fetal cardiac abnormality, fetal movements, fetal lie and twinning. The sensitivity and specificity of detecting cardiac defects were calculated.

RESULTS

The four-chamber view was visualized in 98.1% of fetuses. The sensitivity of detecting a cardiac defect on the four-chamber view was 88% and the specificity 96%. The ability to visualize the left and right outflow tracts was only influenced by the presence of fetal movements: for the left outflow tract 94.4 vs. 50.0% visualization and for the right outflow tract 92.6 vs. 53.8% visualization without and with fetal movements, respectively. The sensitivity of detecting a cardiac defect of the left outflow tract was 63% and the specificity 100%, while sensitivity and specificity were 59 and 97%, respectively, for the right outflow tract.

CONCLUSIONS

Despite the use of SSFP sequences, MRI in the fetal heart remains of limited value. It can only be used as a second-line approach for abnormalities of the four-chamber view suspected at prenatal ultrasound.

Use of a high-frequency linear transducer and MTI filtered color flow mapping in the assessment of fetal heart anatomy at the routine 11 to 13 + 6-week scan: a randomized trial

OBJECTIVE

To prospectively assess the contribution of a high-frequency linear transducer and of moving target indicator (MTI) filtered color flow mapping in the visualization of cardiac fetal anatomy at the routine 11 to 13 + 6-week scan.

METHODS

This was a cross-sectional prospective study, including 300 singleton fetuses at 11 to 13 + 6 weeks' gestation. Patients were randomized into four groups and a detailed fetal cardiac examination was conducted transabdominally using either a conventional curvilinear transducer, a conventional curvilinear transducer and MTI filtered color flow mapping, a high-frequency linear transducer or a high-frequency linear transducer and MTI filtered color flow mapping. Regression analysis was used to investigate the effect on the ability to visualize different cardiac structures of the following parameters: gestational age at ultrasound examination; fetal crown-rump length (CRL); maternal body mass index (BMI); transducer-heart distance; the technique used at ultrasound; and the position of the placenta.

RESULTS

The four-chamber view was visualized in 89.0% of fetuses and regression analysis showed this rate was correlated with CRL and the use of MTI filtered color flow mapping during ultrasonography, and inversely correlated with BMI and transducer-heart distance. Use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the four-chamber view in 97.3% of fetuses, while this was only possible in 84.0% of fetuses using a high-frequency linear transducer. The left and right outflow tracts were visualized in 62.3 and 57.7% of fetuses, respectively. Regression analysis showed that the ability to visualize the left or the right outflow tract was correlated with the use of MTI filtered color flow mapping during scanning and was inversely correlated with transducer-heart distance. The use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the left and right outflow tracts in 96.0 and 97.3% of fetuses, respectively, while this was only possible in 37.3 and 26.7% of fetuses using a high-frequency linear transducer.

CONCLUSIONS

During the routine 11 to 13 + 6-week scan, the use of MTI filtered color flow mapping but not of a high-frequency linear transducer, improves visualization of cardiac anatomy.

Maternal hyperoxygenation test in fetuses undergoing FETO for severe isolated congenital diaphragmatic hernia

OBJECTIVES

To predict neonatal survival and pulmonary hypertension by measurement of fetal pulmonary artery reactivity to maternal hyperoxygenation in fetuses with severe congenital diaphragmatic hernia treated by fetoscopic endoluminal tracheal occlusion (FETO).

METHODS

Thirty-eight fetuses underwent FETO at around 28 weeks' gestation and the balloon was removed at 34 weeks in most cases. We performed a hyperoxygenation test and measured the lung-to-head ratio of each fetus before and after each procedure. Outcome measures were neonatal survival, occurrence of pulmonary hypertension and its response to inhaled nitric oxide (iNO).

RESULTS

Fetuses that survived had a larger increase in lung size and decrease of resistance in the first branch of the main pulmonary artery than did those that died. Both measures were also predictive of pulmonary hypertension unresponsive to iNO. The hyperoxygenation test and lung-to-head ratio were both best predictive for neonatal survival when measured following removal of the balloon (P < 0.002). Discriminant analysis confirmed that these two parameters are independent predictors of outcome.

CONCLUSIONS

In fetuses undergoing FETO, pulmonary vascular reactivity in relation to oxygen and lung size are independent predictors of neonatal survival and pulmonary hypertension. The hyperoxygenation test merits further study in expectantly managed cases.

Three-dimensional ultrasound fetal lung volumes and infant respiratory outcome: a prospective observational study

OBJECTIVE

To determine if fetal lung volumes (FLVs), determined by three-dimensional rotational ultrasound and virtual organ computer-aided analysis software (vocal), correlated with neonatal respiratory outcomes in surviving infants who had a high risk [fetuses with congenital diaphragmatic hernia (CDH)], lower risk [fetuses with anterior wall defects (AWDs)] and no risk (controls) of abnormal antenatal lung growth.

DESIGN

Prospective observational study.

SETTING

Tertiary fetal medicine and neonatal intensive care units.

POPULATION

Sixty fetuses (25 with CDH, 25 with AWDs and ten controls).

METHODS

FLVs were measured and expressed as the percentage of the observed compared with the expected for gestational age.

MAIN OUTCOME MEASURES

Neonatal respiratory outcome was determined by the duration of supplemental oxygen, mechanical ventilation and dependencies, and assessment of lung volume using a gas dilution technique to measure functional residual capacity (FRC).

RESULTS

The infants with CDH had lower FLV results than both the infants with AWDs (P=0.05) and the controls (P<0.05). The infants with CDH had longer durations of mechanical ventilation (P<0.001) and supplementary oxygen (P<0.001) dependence, compared with infants with AWDs. The infants with CDH had a lower median FRC than both the infants with AWDs (P<0.001) and the controls (P<0.001). FLV results correlated significantly with the durations of dependency on ventilation (r= -0.744, P<0.01) and oxygen (r= -0.788, P<0.001), and with FRC results (r=0.429, P=0.001).

CONCLUSIONS

These results suggest that FLVs obtained using three-dimensional rotational ultrasound might be useful in predicting neonatal respiratory outcome in surviving infants who had varying risks of abnormal lung growth. Larger and more comprehensive studies are needed to clarify the role that lung volume measurements have in assessing lung function and growth.

Diffusion-weighted MRI in lungs of normal fetuses and those with congenital diaphragmatic hernia

OBJECTIVE

To prospectively determine apparent diffusion coefficient (ADC) values of normally developing fetal lungs over gestation, as obtained by diffusion-weighted (DW) magnetic resonance imaging (MRI) and to investigate its potential application in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

Informed consent was obtained for this cross-sectional study of 93 fetuses with normal lungs and 14 with isolated left-sided CDH, assessed between 18 and 40 weeks of gestation. MRI delineation of left and right lungs was performed on the native DW image, b0, and three values of ADC, corresponding to the overall value (ADC(avg)), and values for low and high values of b (ADC(low) and ADC(high), respectively) were calculated. Regression analysis was used to assess the relationship between gestational age and b0-values as well as calculated ADC values. The b0 and ADC values of normal and CDH fetuses were compared with normal ranges using the Mann-Whitney U-test.

RESULTS

In fetuses with normal lungs, there was a negative correlation between gestational age and b0 values as well as with ADC(high), a positive correlation with ADC(low) but no correlation with ADC(avg). When measurable, ADC(high) values were lower in CDH as compared to fetuses with normal lungs and ADC(low) values were higher. ADC(low) was unrelated to lung volume.

CONCLUSIONS

There is a significant relationship between ADC(low) and ADC(high) values and gestational age in normal fetal lungs. This relationship is most probably explained by developmental changes during the last three stages of lung development, which involve intense peripheral growth of airways and vessels as well as maturation. In CDH, measurement of ADC(low) might be useful as a predictor of postnatal outcome that is independent of lung volume.

Reference ranges for middle cerebral artery peak systolic velocity in monochorionic diamniotic twins: a longitudinal study

OBJECTIVES

The role of middle cerebral artery (MCA) peak systolic velocity (PSV) has become established in the management of fetal anemia. To date, singleton reference ranges have also been used in twin pregnancies. However, in monochorionic twin pregnancies, normal ranges for cerebral blood flow may differ from those in singletons owing to intertwin blood exchange. We aimed to establish gestational age-specific reference ranges for MCA-PSV in monochorionic diamniotic (MCDA) twin pregnancies, to compare them with previously reported singleton reference ranges, and to establish terms for calculating conditional reference intervals appropriate for individual serial measurements.

METHODS

In a prospective longitudinal study we examined 50 uncomplicated MCDA pregnancies that were recruited between 11 and 14 weeks of gestation. Fetal MCA Doppler waveforms were assessed biweekly from 15 weeks of gestation onwards. Multilevel modeling was used to estimate gestational age-specific reference ranges for MCA-PSV and terms for conditional reference intervals were established.

RESULTS

Based on 824 observations in 100 fetuses, normative ranges from 15 to 37 weeks of gestation were constructed. Median MCA-PSV increased with advancing gestational age. Measurements between 18 and 37 weeks were comparable to those in singletons. However, before 18 weeks MCA-PSV values were higher in MCDA twin pregnancies compared with singleton references.

CONCLUSIONS

Between 18 and 37 weeks of gestation, reference ranges of singletons can be used to assess fetal anemia in MCDA twin pregnancies. Prior to 18 weeks the application of singleton references may lead to an increased number of false-positive diagnoses of presumed fetal anemia in MCDA twin pregnancies.

Drug susceptibility testing of Mycobacterium tuberculosis against second-line drugs using the Bactec MGIT 960 System

OBJECTIVE

To establish the critical test concentrations for seven second-line anti-tuberculosis drugs in the Bactec Mycobacterial Growth Indicator Tube (MGIT) 960 TB system and to evaluate its efficacy compared to the Bactec 460 TB system.

DESIGN

This study was carried out in three phases. In Phase I, pan-susceptible strains were tested to establish the minimum inhibitory concentration; in Phase II, mostly resistant strains were tested to determine a critical test concentration; and in Phase III, actual clinical isolates were tested to validate the optimal critical concentrations established in Phases I and II.

RESULTS

The critical concentrations established for seven second-line drugs with the Bactec MGIT 960 system are amikacin 1.0 microg/ml, capreomycin 2.5 microg/ml, kanamycin 2.5 microg/ml, ofloxacin 2.0 microg/ml, moxifloxacin 1.0 microg/ml, ethionamide 5.0 microg/ml and para-amino salicylic acid 4.0 microg/ml.

CONCLUSION

The Bactec MGIT 960 System is an accurate and reliable method for rapid drug susceptibility testing (DST) of Mycobacterium tuberculosis against second-line drugs. In the present study, few of the strains were resistant to fluoroquinolones and further DST for this group is required.

Value of prenatal magnetic resonance imaging in the prediction of postnatal outcome in fetuses with diaphragmatic hernia

OBJECTIVES

To investigate the potential value of antenatally determined total fetal lung volume (TFLV) by magnetic resonance imaging (MRI) in the prediction of the postnatal survival in congenital diaphragmatic hernia (CDH).

METHODS

We examined fetuses with isolated CDH, in which MRI was used at 22-38 weeks of gestation to measure TFLV and assess intrathoracic herniation of abdominal viscera, that were liveborn after 30 weeks of gestation and had postnatal follow-up until death or discharge from hospital. Regression analysis was used to investigate the effect on survival of gestational age at diagnosis, observed to expected (o/e) TFLV, intrathoracic herniation of the liver, side of CDH, gestational age at MRI, institution, year and gestational age at delivery. In 76 fetuses measurements of o/e TFLV and the lung area to head circumference ratio (LHR) were performed within 2 weeks of each other; in these cases o/e TFLV and o/e LHR were compared for their prediction of postnatal survival.

RESULTS

In the 148 cases that fulfilled the entry criteria, multiple regression analysis demonstrated that significant predictors of survival were the presence or absence of intrathoracic herniation of the liver and o/e TFLV. The area under the receiver-operating characteristics curves for prediction of postnatal survival from o/e TFLV was 0.786 (standard error, 0.059; P < 0.001) and that from o/e LHR was 0.743 (standard error, 0.069; P = 0.001).

CONCLUSIONS

In the assessment of fetuses with CDH, MRI-based o/e TFLV is useful in the prediction of postnatal survival.

Prenatal prediction of survival in isolated diaphragmatic hernia using observed to expected total fetal lung volume determined by magnetic resonance imaging based on either gestational age or fetal body volume

OBJECTIVES

To compare the predictive value of the prenatal observed to expected (o/e) lung volume as measured by fetal magnetic resonance imaging (MRI), based on an algorithm using either the gestational age or fetal body volume (FBV), for neonatal survival of fetuses with isolated congenital diaphragmatic hernia (CDH).

METHODS

We included 53 fetuses with a prenatal diagnosis of isolated CDH, 26 without and 27 with prenatal tracheal occlusion, who were assessed by fetal MRI, liveborn after 32 weeks, and in whom follow-up until discharge from the neonatal care unit was available. Measurements of lung volumes were expressed as a percentage of the appropriate mean (o/e total fetal lung volume (TFLV) x 100) either for gestational age or for FBV. Measurements of FBV were expressed as a percentage of the appropriate mean (o/e FBV x 100) for gestation. Fetuses with prenatal intervention were all assessed > or = 24 h after balloon removal. Regression analysis was used to examine the effect on postnatal survival of either o/e TFLV based on gestational age or based on FBV, gestation at delivery, side of CDH, intrathoracic position of the liver and prenatal intervention. Receiver-operating characteristics (ROC) curves were constructed for the prediction of survival by o/e TFLV based on gestational age and o/e TFLV based on FBV, for all fetuses, as well as for those with o/e FBV between 90 and 110% and those with values beyond that range. A power calculation for the number of fetuses needed to show a difference between the ROC curves was performed.

RESULTS

Regression analysis demonstrated that o/e TFLV based on gestational age and on FBV were the only independent predictors of postnatal survival. The area under the ROC curve for prediction of postnatal survival from the o/e TFLV based on gestational age was 0.811, and for that based on FBV it was 0.868 (P < 0.001 for both). For fetuses with o/e FBV between 90 and 110%, and those with values < 90% and > 110%, the area for measurements based on gestational age was 0.895 and 0.733, respectively; when based on FBV it was 0.906 and 0.833 (P < 0.01 for all). A minimum of 273 patients would be needed to provide a probability of 90% of detecting a difference between the areas under both ROC curves.

CONCLUSIONS

In fetuses with isolated CDH, lung volume as measured by fetal MRI was significantly correlated with survival. Prediction tended to be better by o/e TFLV based on FBV rather than gestational age. The difference in the prediction of survival between o/e TFLV based on FBV or gestational age was dependent on fetal biometry.

Quantification of intrathoracic liver herniation by magnetic resonance imaging and prediction of postnatal survival in fetuses with congenital diaphragmatic hernia

OBJECTIVE

To quantify the degree of intrathoracic liver herniation by magnetic resonance imaging (MRI) and evaluate its effect on postnatal survival in fetuses with isolated congenital diaphragmatic hernia (CDH).

METHODS

Forty fetuses that were expectantly managed and that were delivered after 32 weeks' gestation were included in this study. On axial T2 weighted MR images the degree of intrathoracic liver herniation was measured by volumetry, using the xyphoid process and thoracic apex as landmarks. The ratio of the volume of the liver that was herniated into the thoracic cavity to the volume of the thoracic cavity was calculated (LiTR). All the fetuses also underwent lung volumetry, and the ratio of the observed/expected total fetal lung volume (o/e TFLV) was calculated. Regression analysis was used to investigate the effect on survival of side of occurrence of CDH, o/e TFLV, LiTR and gestational age at delivery. Receiver-operating characteristics (ROC) curves were constructed to examine the prediction of survival by o/e TFLV or LiTR alone and o/e TFLV and LiTR together.

RESULTS

Univariate regression analysis demonstrated that significant predictors of survival were o/e TFLV and LiTR. Multiple regression analysis demonstrated that o/e TFLV and LiTR provided independent prediction of survival. The area under the ROC curve (AUC) for the prediction of postnatal survival from o/e TFLV alone was 0.846 (P < 0.001; SE = 0.062) and the AUC from LiTR alone was 0.875 (P = 0.001; SE = 0.072). The AUC for the prediction of postnatal survival from o/e TFLV and LiTR combined was 0.912 (P < 0.001; SE = 0.045), however it was not statistically significantly different from that of o/e TFLV alone.

CONCLUSION

In expectantly managed CDH fetuses, assessment of LiTR using MRI provided prediction of postnatal survival independently from o/e TFLV.

Association between intrapulmonary arterial Doppler parameters and degree of lung growth as measured by lung-to-head ratio in fetuses with congenital diaphragmatic hernia

OBJECTIVES

To describe the association between the intrapulmonary circulation and the degree of lung growth in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

Thirty-six fetuses with isolated left CDH at 22-29 weeks of gestation were studied. Four groups were defined according to lung-to-head ratio (LHR), expressed as the ratio of observed to expected LHR for gestational age (O/E LHR). Pulsatility index (PI), peak systolic velocity (PSV), peak early-diastolic reversed flow (PEDRF), end-diastolic velocity (EDV), acceleration time (AT), time averaged velocity (TAV) and the ratio AT to ejection time (AT/ET) were measured in all fetuses in the proximal arterial branch of both lungs. For analysis, Doppler values were converted to Z-scores.

RESULTS

It was possible to record all Doppler parameters from the contralateral lung of all CDH fetuses, and from the ipsilateral lung in 28 (77.7%). PEDRF significantly increased in relation to the decrease in O/E LHR in both lungs (contralateral: r = - 0.65, P = 0.01; ipsilateral: r = - 0.43, P = 0.02). PI increased significantly with the reduction in O/E LHR but only on the side contralateral to the hernia (r = - 0.55, P = 0.02). In the ipsilateral pulmonary artery, PI values showed a significant overall increase but no differences were observed among the O/E LHR groups. PSV, EDV and TAV were reduced in both lungs with respect to normal values, but no association was found with the O/E LHR. No changes in AT or AT/ET were observed in either lung.

CONCLUSIONS

PEDRF is quick and easy to calculate, and showed the strongest and most consistent correlation with O/E LHR. The association between PEDRF and LHR might be an additional parameter that could help to establish prognosis in fetuses with CDH.

Timing of lung size assessment in the prediction of survival in fetuses with diaphragmatic hernia

OBJECTIVES

To investigate whether the prediction of postnatal outcome of fetuses with isolated congenital diaphragmatic hernia depends on the gestational age at assessment using the fetal observed to expected (O/E) lung area to head circumference ratio (LHR), by comparing the performance of the test at 22-23 weeks with that at 32-33 weeks of gestation.

METHODS

Following prenatal diagnosis of isolated diaphragmatic hernia before 22 weeks, we evaluated the O/E LHR at 22-32 weeks and again at 32-33 weeks of gestation. Only cases liveborn beyond 34 weeks of gestation and with postnatal follow-up available until discharge from the hospital were included. Regression analysis was used to examine the effect on postnatal survival of O/E LHR, gestational age at delivery, side of the diaphragmatic hernia and intrathoracic position of the liver. Wilcoxon rank test for paired samples was used to compare median O/E LHR at 22-23 weeks and 32-33 weeks, in babies who survived and in those who died. Receiver-operating characteristics (ROC) curves were constructed for the prediction of survival by O/E LHR at 22-23 weeks and at 32-33 weeks.

RESULTS

In total, 53 pairs of measurements could be assessed. Univariate logistic regression analysis demonstrated that significant predictors of survival were the presence or absence of intrathoracic herniation of the liver, the O/E LHR at 22-23 weeks and the O/E LHR at 32-33 weeks of gestation. Multivariate logistic regression analysis demonstrated that only O/E LHR at 22-23 weeks or 32-33 weeks provided significant independent prediction of survival. The median O/E LHR at 22-23 weeks was not significantly different from that at 32-23 weeks either in survivors or in babies that subsequently died in the neonatal period (P = 0.25 and P = 0.09, respectively). The area under the ROC curve for prediction of postnatal survival from the O/E LHR at 22-23 weeks was 0.789 (P < 0.001) and that for prediction from the O/E LHR at 32-33 weeks was 0.842 (P < 0.001).

CONCLUSIONS

In isolated diaphragmatic hernia, O/E LHR measurement at 22-23 weeks as well as at 32-33 weeks provides useful independent prediction of subsequent survival. The prediction of postnatal survival using O/E LHR is independent of the timing of assessment.

Relationship between lung area at ultrasound examination and lung volume assessment with magnetic resonance imaging in isolated congenital diaphragmatic hernia

OBJECTIVES

To prospectively examine the relationship between contralateral lung area measured by two-dimensional (2D) ultrasound examination and contralateral and total fetal lung volume (FLV) estimated by magnetic resonance imaging (MRI) in the assessment of fetuses with congenital diaphragmatic hernia (CDH).

METHODS

Sixty-six fetuses with isolated CDH were entered in this prospective study. Contralateral fetal lung area was measured by 2D ultrasonography using the longest axis method. Ipsilateral, contralateral and total FLV were measured using multiplanar axial T2-weighted MRI. Regression analysis was used to determine the significance of associations between contralateral lung area and contralateral and total FLV, and the predicted total FLV was subsequently calculated using the regression equation. Univariate regression analysis was used to investigate the effect on the proportionate difference between the predicted and the observed total FLV of gestational age, proportionate volume of ipsilateral vs. total FLV, side of CDH, intrathoracic herniation of the liver and intratracheal presence of a balloon.

RESULTS

The 66 fetuses underwent a total of 191 paired 2D ultrasound and MRI examinations at a median gestational age of 30 (range, 18-38) weeks. It was possible to visualize and measure the contralateral lung area by 2D ultrasound, as well as both the ipsilateral and contralateral lung volumes by MRI, in all instances. There was a significant association between contralateral lung area and contralateral lung volume (r = 0.86; P < 0.001) and with total FLV (r = 0.84; P < 0.001). Univariate regression analysis showed that the proportionate difference between the predicted and the observed total FLV was significantly associated with the proportionate volume of ipsilateral vs. total FLV but not with gestational age, side of CDH, intrathoracic herniation of the liver or intratracheal presence of the balloon.

CONCLUSIONS

In CDH, contralateral lung area measurement by 2D ultrasound correlates well with the total FLV estimated by MRI, irrespective of gestational age, liver herniation or side of herniation. Inconsistencies between the two measurements are attributable to the contribution of the ipsilateral lung to the total lung volume.

A diffusion-weighted template for gestational age-related apparent diffusion coefficient values in the developing fetal brain

OBJECTIVE

To determine the pattern of apparent diffusion coefficient (ADC) values in the normal fetal brain obtained with diffusion-weighted images (DWI) on magnetic resonance imaging (MRI) as a template for normal brain development throughout gestation.

METHODS

This was a prospective study of 46 fetuses without suspicion of brain pathology undergoing a total of 66 ultrasound examinations between 17 and 37 weeks of gestation. At T2-weighted MRI, four left and four right brain regions were delineated on transverse slices of the native DWI using a b-value of 0 s/mm2 (b0 images). We examined native b-value images and calculated ADC(avg), ADC(low) and ADC(high) in the basal ganglia, cerebellar hemisphere, frontal parenchyma and occipital parenchyma. Linear regression analysis was used to assess the relationship between gestational age and b0 values as well as the calculated ADC values.

RESULTS

Delineations were successful in all fetuses for all regions except for the cerebellar hemispheres in four fetuses. There was a negative correlation between gestational age and b0 values in all examined anatomical regions (P<0.002). For ADC(avg), there were no significant changes in the basal ganglia with increasing gestational age, a positive correlation in the frontal (P<0.0001) and occipital (P=0.03) parenchyma and a negative correlation in the cerebellar hemispheres (P=0.01). For ADC(low), there was a negative correlation between gestational age and the cerebellum (P=0.0002) and basal ganglia (P=0.047), but no correlation for the frontal or occipital parenchyma. For ADC(high), there was a positive correlation with gestational age for the frontal parenchyma (P=0.004), occipital parenchyma (P=0.02) and basal ganglia (P=0.03) but there was no correlation for the cerebellum.

CONCLUSIONS

DWI b0 values decreased in the left and right basal ganglia, cerebellar hemisphere, frontal parenchyma and occipital parenchyma between 17 and 37 weeks of gestation and ADC(avg) values increased in two out of four cerebral regions. It remains to be determined to what extent these observations differ in fetuses with suspicion of brain anomalies and whether such measurements will be useful and more predictive of outcome compared with standard MRI sequences.

Assessment of lung area in fetuses with congenital diaphragmatic hernia

OBJECTIVE

To compare the intra- and interobserver agreement of three different methods of measuring lung area in fetuses with congenital diaphragmatic hernia (CDH).

METHODS

In 71 fetuses with isolated CDH at 21-33 weeks' gestation, the area of the contralateral lung was assessed by firstly, manual tracing of lung borders, secondly, multiplication of the longest diameter of the lung by its widest perpendicular diameter, and thirdly, multiplication of the anteroposterior (AP) diameter of the lung at the mid-clavicular line by the perpendicular diameter at the midpoint of the AP diameter (AP method). In 30 fetuses the measurements were made by two observers and Bland-Altman analysis was used to compare the measurement agreement and bias for each observer and between the two observers.

RESULTS

The area obtained by the AP method was similar to that obtained by the manual tracing method, but the area by the longest diameter approach was bigger by 34.4% (95% CI, - 2.4% to 71.1%). The 95% confidence intervals of the difference in paired measurements of lung areas by the same observer and by two different observers were narrower in the manual tracing method than in the multiplying diameters methods.

CONCLUSIONS

In CDH the most reproducible measurement of fetal lung area is provided by manual tracing of the limits of the lungs, rather than by multiplication of lung diameters.

Observed to expected lung area to head circumference ratio in the prediction of survival in fetuses with isolated diaphragmatic hernia

OBJECTIVE

To assess the value of antenatally determined observed to expected fetal lung area to head circumference ratio (LHR) in the prediction of postnatal survival in isolated, congenital diaphragmatic hernia (CDH).

METHODS

Two groups of fetuses were examined. The first group included 650 normal fetuses at 12-32 weeks' gestation, and the data collected were used to establish a normal range of observed to expected LHR with gestational age. The second group included the data of a retrospective multicenter study of 354 fetuses with isolated CDH in which the LHR was measured on one occasion at 18-38 weeks' gestation. The patients were divided into those with left-sided CDH with and without intrathoracic herniation of the liver and right-sided CDH. Regression analysis was used to determine the significant predictors of postnatal survival.

RESULTS

In both the normal fetuses and those with CDH the LHR increased but the observed to expected LHR did not change significantly with gestational age. In normal fetuses the mean observed to expected LHR in the left lung was 100% (95% CI, 61-139%) and in the right lung it was 100% (95% CI, 67-133%). In fetuses with CDH the mean observed to expected LHR was 39% (range 7-79%). Regression analysis demonstrated that significant predictors of survival were the observed to expected LHR (odds ratio (OR) 1.09, 95% CI, 1.06-1.12), side of CDH (left side OR 11.14, 95% CI, 3.41-36.39) and gestational age at delivery (OR 1.18, 95% CI, 1.02-1.36).

CONCLUSION

In CDH, the LHR increases while observed to expected LHR is independent of gestational age. In fetuses with both left- and right-sided CDH, measurement of the observed to expected LHR provides a useful prediction of subsequent survival.

Prenatal detection and outcome of congenital diaphragmatic hernia: a French registry-based study

OBJECTIVES

To describe the true incidence, prenatal detection rate and fetal outcome of congenital diaphragmatic hernia (CDH) in a systematically registered population over an 18-year period and to determine any change in trends over time.

METHODS

This was a retrospective study of all cases of CDH registered in the Central-Eastern France Birth Defects Registry from 1986 to 2003. All fetuses and infants up to 1 year of age diagnosed with CDH were registered, including miscarriages later than 22 weeks of gestation, stillbirths and terminations of pregnancy (TOP). Routine prenatal screening consisted of three ultrasound examinations and there was no upper limit of gestational age for TOP.

RESULTS

Five hundred and one cases of CDH were identified from a total of 1 835 022 live births (2.7 cases per 10 000 live births). The overall prenatal detection rate was 54%. There was a significant increase over time in the detection rate mainly for associated CDH and left-sided CDH (P < 0.0001), and in the proportion of neonates delivered in tertiary centers (P < 0.0001). The overall survival rate at discharge was 47% and this increased significantly over time for isolated CDH (P = 0.04), whereas it was lower and remained stable for associated CDH (P = 0.64). The TOP rate for isolated CDH did not vary significantly in contrast to that for associated CDH cases in which the TOP rate increased over time, progressively replacing the neonatal death rate (P = 0.01).

CONCLUSIONS

Over an 18-year period, this large population-based study demonstrated increasing prenatal detection rates for associated CDH and left-sided CDH and confirmed an increasing survival rate mainly for isolated CDH.