Assessment of fetal optic chiasm: an echoanatomic and reproducibility study.

OBJECTIVES: Our aims were: (1) to perform an echoanatomic correlation study, in order to confirm that the structure identified as the optic chiasm (OC) on ultrasound (US) is indeed this anatomical structure; (2) to assess and compare the reproducibility of two- (2D) and three-(3D) dimensional US in measurement of the OC in normal fetuses; and (3) to assess whether the spatial orientation of the OC changes with increasing gestational age. METHODS: For the echoanatomic study, the OC was studied in a neonatal specimen, deceased at 29 + 4 weeks, by passing a suture around the OC and visualizing the supposed OC structure on US while pulling gently on the suture. The reproducibility study included 39 women with normal pregnancy at 20-33 weeks undergoing routine obstetric US examination. After the routine exam, the OC was visualized on 2D-US, and a 2D image and 3D volume dataset were stored for offline measurement. On the 2D images, the diameters of the OC decussation and the optic tract proximal to the transducer were measured. For the 3D volume dataset, multiplanar image correlation with volume contrast imaging (VCI) was used to measure both these diameters and the chiasmocallosal angle (CCA). Two operators each took two sets of measurements of the diameters on 2D- and 3D-US, and intra- and interoperator variability were analyzed using Cronbach's alpha intraclass correlation coefficient (ICC), while a single operator took two sets of CCA measurements for assessment of intraoperator variability. Differences in CCA with increasing gestational age were also analyzed by regression, and CCA measurements were divided into three groups according to gestational age and their means compared by one-way ANOVA. RESULTS: During the echoanatomic experiment, when the sling suture was pulled, the hyperechoic X-shaped structure just below the circle of Willis identified on 2D-US as the OC was displaced slightly and was eventually cut by the sling, confirming its identity as the OC. Intraoperator variability was low and almost identical for the two operators and the two imaging modalities for measurement of the decussation (ICC for 2D-US: 0.96 vs 0.95; 3D-US: 0.95 vs 0.96), but less so for the optic tract (ICC for 2D-US: 0.95 vs 0.91; 3D-US: 0.94 vs 0.83). Interoperator variability was low for the decussation (2D-US: 0.92; 3D-US: 0.92), but higher for the optic tracts (ICC for 2D-US: 0.80; 3D-US: 0.78). The difference between the mean measurement of the two operators was not statistically significantly different for the decussation, but it was for the optic tracts (P = 0.04). The CCA increased steadily between 20 and 30 gestational weeks and plateaued thereafter, at least until 33 weeks. CONCLUSIONS: The hyperechoic structure evident on 2D- and 3D-US, just below the circle of Willis, is indeed the OC. 2D-US is apparently as good as 3D-US for visualization of the OC. However, only measurement of the decussation showed low intra- and interoperator variability, whereas measurement of the optic tract is of questionable variability. As gestation advances between 20 and 30 weeks, the OC becomes more oblique in orientation. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Clinically oriented three-step strategy for assessment of adnexal pathology.

OBJECTIVE: To determine the diagnostic performance of ultrasound-based simple rules, risk of malignancy index (RMI), two logistic regression models (LR1 and LR2) and real-time subjective assessment by experienced ultrasound examiners following the exclusion of masses likely to be judged as easy and 'instant' to diagnose by an ultrasound examiner, and to develop a new strategy for the assessment of adnexal pathology based on this. METHODS: 3511 patients with at least one persistent adnexal mass preoperatively underwent transvaginal ultrasonography to assess tumor morphology and vascularity. They were included in two consecutive prospective studies by the International Ovarian Tumor Analysis (IOTA) group: Phase 1 (1999-2005), development of the simple rules and logistic regression models LR1 and LR2, and Phase 2, a validation study (2005-2007). RESULTS: Almost half of the cases (43%) were identified as 'instant' to diagnose on the basis of descriptors applied to the database. To assess diagnostic performance in the more difficult 'non-instant' masses, we used only Phase 2 data (n = 1036). The sensitivity of LR2 was 88%, of RMI it was 41% and of subjective assessment it was 87%. The specificity of LR2 was 67%, of RMI it was 90% and of subjective assessment it was 86%. The simple rules yielded a conclusive result in almost 2/3 of the masses, where they resulted in sensitivity and specificity similar to those of real-time subjective assessment by experienced ultrasound examiners: sensitivity 89 vs 89% (P = 0.76), specificity 91 vs 91% (P = 0.65). When a three-step strategy was applied with easy 'instant' diagnoses as Step 1, simple rules where conclusive as Step 2 and subjective assessment by an experienced ultrasound examiner in the remaining masses as Step 3, we obtained a sensitivity of 92% and specificity of 92% compared with sensitivity 90% (P = 0.03) and specificity 93% (P = 0.44) when using real-time subjective assessment by experts in all tumors. CONCLUSION: A diagnostic strategy using simple descriptors and ultrasound rules when applied to the variables contained in the IOTA database obtains results that are at least as good as those obtained by subjective assessment of a mass by an expert.

Role of four-dimensional ultrasound (spatiotemporal image correlation and sonography-based automated volume count) in prenatal assessment of atrial morphology in cardiosplenic syndromes.

OBJECTIVE: To assess the diagnostic role of four-dimensional ultrasound using spatiotemporal image correlation and Sonography-based Automated Volume Count (STIC-SonoAVC) in the identification of the morphology of the atrial appendages in cases with cardiosplenic syndrome. METHODS: This was a retrospective investigation of 22 fetuses with cardiosplenic syndromes seen at our institution over a 5-year period from January 2004. As control groups, 10 normal fetuses, five cases with a non-isomeric atrioventricular septal defect and five cases with other congenital heart diseases were also analyzed. For all fetuses, one or more cardiac volume datasets were available for offline analysis. Two-dimensional and four-dimensional echocardiography was carried out in all cases at the time of diagnosis using high quality three-dimensional equipment. Dedicated software was used to assess chamber morphology using the SonoAVC technique, which allows the creation of casts of hollow structures. Two different operators used the software. The first performed all steps up to positioning of the region of interest box. The second operator, who was blinded to clinical information, then rendered the cardiac chambers using the SonoAVC technique. This operator then used the rendered image to subjectively assess atrial morphology. RESULTS: Suitable rendered images of the cardiac chambers could be produced in 40/42 fetuses. In two cases of left atrial isomerism, advanced (34 weeks) and early (13 weeks) gestational age made it impossible to obtain adequate rendered images. In the remaining 40 cases (13 cases of left atrial isomerism, seven cases of right atrial isomerism, five cases of non-isomeric atrioventricular septal defect, five cases of other congenital heart diseases and 10 normal fetuses), atrial morphology was correctly identified by evaluation of the rendered images. CONCLUSION: Four-dimensional ultrasound with SonoAVC rendering allows correct identification of the morphology of atrial appendages in all cases of cardiosplenic syndromes in which an adequate cardiac volume dataset can be obtained for analysis.

Effect of cancer prevalence on the use of risk-assessment cut-off levels and the performance of mathematical models to distinguish malignant from benign adnexal masses.

OBJECTIVE: Two logistic regression models have been developed for the characterization of adnexal masses. The goal of this prospective analysis was to see whether these models perform differently according to the prevalence of malignancy and whether the cut-off levels of risk assessment for malignancy by the models require modification in different centers. METHODS: Centers were categorized into those with a prevalence of malignancy below 15%, between 15 and 30% and above 30%. The areas under the receiver-operating characteristics curves (AUC) were compared using bootstrapping. The optimal cut-off level of risk assessment for malignancy was chosen per center, corresponding to the highest sensitivity level possible while still keeping a good specificity. RESULTS: Both models performed better in centers with a lower prevalence of malignant cases. The AUCs of the two models for centers with fewer than 15% malignant cases were 0.97 and 0.95, those of centers with 15-30% malignancy were 0.95 and 0.93 and those of centers with more than 30% malignant cases were 0.94 and 0.92. This decrease in performance was due mainly to the decrease in specificity from over 90 to around 76%. In the centers with a higher percentage of malignant cases, a sensitivity of at least 90% with a good specificity could not be obtained by choosing a different cut-off level. CONCLUSIONS: Overall the models performed well in all centers. The performance of the logistic regression models worsened with increasing prevalence of malignancy, due to a case mix with more borderline and complex benign masses seen in those centers. Because the cut-off of 0.10 is optimal for all three types of center, it seems reasonable to use this cut-off for both models in all centers.

Transposition of the great arteries in the fetus: assessment of the spatial relationships of the arterial trunks by four-dimensional echocardiography.

OBJECTIVE: Coronary arterial abnormalities can be one of the few negative prognostic indicators in transposition of the great arteries (TGA), and their occurrence is related to the type of spatial relationship of the great arteries. The main objective of this study was to assess whether the use of the reconstructed en-face view with color Doppler imaging of the four cardiac valves can demonstrate the different types of spatial relationship of the arterial trunks in fetuses with TGA, in order to derive the risk of coronary abnormalities. A secondary end-point was the evaluation of the type of coronary arterial branching pattern. METHODS: Twenty-three fetuses with a confirmed diagnosis of TGA underwent four-dimensional (4D) echocardiography at 19-33 gestational weeks. The en-face view of the four cardiac valves and color Doppler with high persistence were employed to assess the spatial relationships of the great arteries. In all cases, confirmation of the vessels' arrangement and coronary arterial distribution was obtained at neonatal echocardiography and/or surgery. RESULTS: The spatial relationships of the great vessels was identified correctly in 20/23 (87%) cases. The aorta was found to be located anterior to and to the right of the pulmonary trunk in 13/23 (56.5%) cases and just anterior to the pulmonary artery in 6/23 (26.1%) cases; in the remaining four (17.4%) cases, the two vessels were side by side. With respect to the association between the spatial relationship of the great arteries and the occurrence of an unusual pattern of coronary arterial branching, five of the TGA fetuses had abnormal coronary arterial distribution. CONCLUSIONS: Using 4D echocardiography with color Doppler, it is possible to define the spatial relationships of the great arteries in fetuses with TGA with a high degree of accuracy. This information can be used during counseling to predict the likelihood of abnormal coronary arterial distribution.

Echocardiographic assessment of ventricular filling pressure during the second and third trimesters of gestation.

AIMS: To confirm changes in the atrioventricular diastolic flow velocities (peak E, peak A, E/A ratio) with gestational age and to define whether these changes genuinely reflect variations in filling pressure in the fetal heart. METHODS: Fifty normal pregnancies were studied between the 13th and the 37th weeks of gestation. The fetal flow velocity patterns were evaluated by pulsed-wave (PW) Doppler and the annular velocities of the atrioventricular valves by PW-Doppler tissue imaging (DTI). RESULTS: All indexes evaluated (atrioventricular peak flow and annular velocities) correlated significantly with gestational age. This correlation was stronger for the early diastolic indexes (tricuspid E and EA, 0.69 and 0.78; mitral E and EA, 0.61 and 0.77, respectively) and weaker for the end-diastolic indexes (tricuspid A and AA, 0.46 and 0.37; mitral A and AA, 0.45 and 0.39, respectively). Neither mitral nor tricuspid E/Ea ratio changed significantly with gestational age. CONCLUSIONS: The lack of correlation between the Doppler-assessed ventricular filling pressures and gestational age suggests absence of significant changes of ventricular compliance during the second and third trimesters of pregnancy, and a progressive enhancement of active relaxation and/or changes in loading conditions.