Comparison of ex-vivo high-resolution episcopic microscopy with in-vivo four-dimensional high-resolution transvaginal sonography of the first-trimester fetal heart

Quantitative Image Processing for Three-Dimensional Episcopic Images of Biological Structures: Current State and Future Directions

Episcopic imaging using techniques such as High Resolution Episcopic Microscopy (HREM) and its variants, allows biological samples to be visualized in three dimensions over a large field of view. Quantitative analysis of episcopic image data is undertaken using a range of methods. In this systematic review, we look at trends in quantitative analysis of episcopic images and discuss avenues for further research. Papers published between 2011 and 2022 were analyzed for details about quantitative analysis approaches, methods of image annotation and choice of image processing software. It is shown that quantitative processing is becoming more common in episcopic microscopy and that manual annotation is the predominant method of image analysis. Our meta-analysis highlights where tools and methods require further development in this field, and we discuss what this means for the future of quantitative episcopic imaging, as well as how annotation and quantification may be automated and standardized across the field.

Can Fetal Echocardiographic Measurements of the Left Ventricular Outflow Tract Angle Detect Fetuses with Conotruncal Cardiac Anomalies?

OBJECTIVES

The angle between the inter-ventricular septum and the ascending aorta can be measured during a sonographic fetal survey while viewing the left ventricular outflow tract (LVOT angle). Our aim was to compare the LVOT angle between fetuses with and without conotruncal cardiac anomaliesrmations.

METHODS

In this prospective observational study, we compared the LVOT angle between normal fetuses, at different gestational age, and fetuses with cardiac malformations.

RESULTS

The study included 302 fetuses screened at gestational age of 12-39 weeks. The LVOT angle ranged from 127 to 163 degrees (mean 148.2), in 293 fetuses with normal hearts, and was not correlated with gestational age. The LVOT angle was significantly wider in fetuses with D-transposition of the great arteries (D-TGA, eight fetuses) and valvar aortic stenosis (AS, three fetuses), than in fetuses with normal hearts (164.8 ± 5.0 vs. 148.2 ± 5.4, respectively, p < 0.001). Conversely, the LVOT angle was significantly narrower in fetuses with complete atrioventricular canal defect (AVC, eight fetuses), than in fetuses with normal hearts (124.8 ± 2.4 vs. 148.2 ± 5.4, respectively, p < 0.001). On ROC analysis, an angle of 159.6 degrees or higher had a sensitivity of 100% and a specificity of 97.3% for the detection of TGA or AS, whereas an angle of 128.8 degrees or lower had a sensitivity of 100% and a specificity of 99.7% for the detection of AVC defect.

CONCLUSIONS

The LVOT angle is constant during pregnancy, and differs significantly in fetuses with TGA/AS, and AVC, compared to fetuses with normal hearts (wider and narrower, respectively).

Micro-computed tomography of isolated fetal hearts following termination of pregnancy: A feasibility study at 8 to 12 weeks' gestation

OBJECTIVES

To assess the feasibility of retrieval of intact human fetal hearts after first trimester surgical termination of pregnancy (TOP) and subsequent anatomical assessment by postmortem micro-computed tomography (micro-CT).

METHODS

In a cohort of consenting women undergoing surgical TOP between 8 and 13 weeks' gestation, we attempted the retrieval of the fetal heart from the suction material. Specimens were immersion fixed in 10% formaldehyde, scanned by iodine-enhanced micro-CT and cardiac anatomy assessed by a multidisciplinary team using 3D-multiplanar analysis.

RESULTS

The median gestational age at TOP was 10.7 weeks (range 8.3-12.9). In 57 (95.0%) out of 60 suction specimens, the heart could be retrieved. The median cardiac length was 5 mm (range 2-8 mm), in three (5.3%), the heart was too damaged to assess cardiac anatomy and in five (8.7%) only the four chambers could be examined. In the remaining 49 (86.0%) cases, a detailed assessment of cardiac anatomy was possible, showing a major defect in two (4.1%) and a minor defect in four (8.2%).

CONCLUSIONS

Fetal hearts can be retrieved after first trimester TOP being intact in the vast majority of cases. Iodine-enhanced, postmortem micro-CT can be used to assess cardiac anatomy from as early as 8 weeks and to describe heart abnormalities.

High-Resolution Episcopic Microscopy (HREM): Looking Back on 13 Years of Successful Generation of Digital Volume Data of Organic Material for 3D Visualisation and 3D Display

High-resolution episcopic microscopy (HREM) is an imaging technique that permits the simple and rapid generation of three-dimensional (3D) digital volume data of histologically embedded and physically sectioned specimens. The data can be immediately used for high-detail 3D analysis of a broad variety of organic materials with all modern methods of 3D visualisation and display. Since its first description in 2006, HREM has been adopted as a method for exploring organic specimens in many fields of science, and it has recruited a slowly but steadily growing user community. This review aims to briefly introduce the basic principles of HREM data generation and to provide an overview of scientific publications that have been published in the last 13 years involving HREM imaging. The studies to which we refer describe technical details and specimen-specific protocols, and provide examples of the successful use of HREM in biological, biomedical and medical research. Finally, the limitations, potentials and anticipated further improvements are briefly outlined.

Morphological features of atrial myocardium embryonic development and its changes caused by hypoxia effect

Mortality and morbidity during the prenatal period of development remain a real problem at the present time. The Scientific Committee EURO-PERISTAT has revealed that mortality of fetuses associated with congenital abnormalities is on average 15–20% across Europe. Hypoxia is one of the top causes of death of fetuses. Since the heart begins to function before birth, influence of teratogenic factors leads to formation of anomalies of its development. Congenital heart defects are the most common of these and occur with a frequency of 24%. Abnormalities associated with the atrium occur with frequency of 6.4 per 10,000 cases. Investigation of structural changes of the atrial myocardium is a key for understanding of pathogenic mechanisms of cardiovascular diseases that are caused by influence of hypoxia. Nowadays, a great deal of research is being dedicated to normal cardiogenesis and much less work is focused on abnormal heart development. There are numerous teratogenic factors such as alcohol, retinoic acid, hyperthermia, hypoxia that are most common causes of heart diseases. The attention of researchers has been predominantly focused on study of changes of the ventricular myocardium under the effect of hypoxia. It is known that the atrium is different from the ventricles by derivation, development and structure. Therefore, the effects of pathological factors on the atrial myocardium will be different as complared to their effect on the ventricles. Also, almost all research has focused on study of consequences of hypoxia at the late stages of cardiogenesis. However, the greatest number of abnormalities is associated with the early embryonic period, as structures that continue development are more sensitive to the effects of harmful factors. Thus, comparative analysis of scientific research devoted to morphological study of atrial myocardium transformations on the cellular and ultrastructural levels under the influence of hypoxia during the stages of cardiogenesis is an important task.

Feasibility of detection of the 3-vessel and trachea view using 3-dimensional sonographic volumes

OBJECTIVES

The purpose of this study was to investigate the ability to depict the 4-chamber and 3-vessel and trachea views of the fetal heart using 3-dimensional sonography.

METHODS

Three-dimensional color Doppler volumes of the fetal heart were acquired prospectively in 31 fetuses between 19 and 25 gestational weeks. The initial plane consisted of the 4-chamber view. Postprocessing included navigation within the volume solely in plane A in the caudal direction to visualize the stomach and in the cephalic direction to the plane of the 3-vessel and trachea view to visualize the pulmonary artery, the aorta, the V shape and color of the arches, the superior vena cava, and the trachea. The feasibility of showing these organs was evaluated.

RESULTS

The estimated time for volume acquisition and manipulation was about 60 seconds. The detection rates for the 4-chamber view, stomach, 3-vessel view, trachea, and V sign were 100%, 93.5%, 92.0%, 77.4%, and 83.9%, respectively, with interobserver agreement of 0.76 to 1.0.

CONCLUSIONS

We describe a simple technique in which a single sweep on 3-dimensional sonography starting at the level of the 4-chamber view can visualize the situs, stomach, 4-chamber view, and transverse view of the outflow tracts of the heart.