PurposeRapid advances in perinatal medicine have resulted in increased number of various tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for external dimensions of the trachea at varying gestational age.Materials and methodsUsing anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (ANOVA, regression analysis), a range of measurements (prebifurcation and bifurcation lengths, proximal and distal external transverse diameters, proximal external cross-sectional area, and external volume) for the trachea in 73 spontaneously aborted fetuses (39 male, 34 female) aged 14–25 weeks was examined.ResultsNo significant male–female differences were found (P > 0.05). The prebifurcation and bifurcation lengths ranged from 8.14 ± 1.90 to 20.77 ± 0.50 mm and from 2.23 ± 0.25 to 5.77 ± 0.76 mm, according to the functions y = −54.291 + 23.940 × ln (Age) ± 1.681 (R2 = 0.78) and y = −10.756 + 4.860 × ln (Age) ± 0.731 (R2 = 0.44), respectively. Their relative growth, expressed as the bifurcation-to-prebifurcation length ratio, was stable from the age of 16 weeks and attained the value 0.22 ± 0.05. The proximal external transverse diameter of the trachea was greater (36 fetuses, 49.3%), smaller (34 fetuses, 46.6%) or similar (3 fetuses, 4.1%), when compared to the distal external transverse diameter. The values for proximal and distal transverse diameters ranged from 2.39 ± 0.04 to 5.20 ± 0.17 mm and from 2.42 ± 0.20 to 4.93 ± 0.08 mm, expressed by the functions: y = −9.659 + 4.574 × ln (Age) ± 0.313 (R2 = 0.79) and y = −10.897 + 4.984 × ln (Age) ± 0.327 (R2 = 0.81). The values of proximal external cross-sectional area ranged from 3.38 ± 0.12 to 15.98 ± 1.04 mm2, according to the linear function y = −11.798 + 1.077 × Age ± 1.463 (R2 = 0.78). The values of external volume of the trachea ranged from 34.3 ± 11.6 to 370.6 ± 94.1 mm3 and generated the quadratic function y = −154.589 + 0.858 × Age2 ± 34.196 (R2 = 0.87).ConclusionsThe tracheal parameters do not show male–female differences. The developmental dynamics of prebifurcation and bifurcation lengths and proximal and distal external transverse diameters of the trachea follow linear functions dependent on the natural logarithm of fetal age, its external cross-sectional area—according to a linear function, and its external volume—according to a quadratic function.

PurposeDetailed knowledge on the normative growth of the spine is of great relevance in the prenatal diagnosis of its abnormalities. The present study was conducted to compile age-specific reference data for vertebra C4 and its three ossification centers in human fetuses.Materials and methodsWith the use of CT (Biograph mCT), digital image analysis (Osirix 3.9) and statistical analysis (Wilcoxon signed-rank test, Kolmogorov–Smirnov test, Levene’s test, Student’s t test, one-way ANOVA, post hoc RIR Tukey test, linear and nonlinear regression analysis), the normative growth of vertebra C4 and its three ossification centers in 55 spontaneously aborted human fetuses (27 males, 28 females) aged 17–30 weeks was examined.ResultsSignificant differences in neither sex nor laterality were found. The height and transverse and sagittal diameters of the C4 vertebral body increased logarithmically as: y = −3.866 + 2.225 × ln(Age) ± 0.238 (R2 = 0.69), y = −7.077 + 3.547 × ln(Age) ± 0.356 (R2 = 0.72) and y = −3.886 + 2.272 × ln(Age) ± 0.222 (R2 = 0.73), respectively. The C4 vertebral body grew linearly in cross-sectional area as y = −7.205 + 0.812 × Age ± 1.668 (R2 = 0.76) and four-degree polynomially in volume as y = 14.108 + 0.00007 × Age4 ± 6.289 (R2 = 0.83). The transverse and sagittal diameters, cross-sectional area and volume of the ossification center of the C4 vertebral body generated the following functions: y = −8.836 + 3.708 × ln(Age) ± 0.334 (R2 = 0.76), y = −7.748 + 3.240 × ln(Age) ± 0.237 (R2 = 0.83), y = −4.690 + 0.437 × Age ± 1.172 (R2 = 0.63) and y = −5.917 + 0.582 × Age ± 1.157 (R2 = 0.77), respectively. The ossification center-to-vertebral body volume ratio gradually declined with age. On the right and left, the neural ossification centers showed the following growth: y = −19.601 + 8.018 × ln(Age) ± 0.369 (R2 = 0.92) and y = −15.804 + 6.912 × ln(Age) ± 0.471 (R2 = 0.85) for length, y = −5.806 + 2.587 × ln(Age) ± 0.146 (R2 = 0.88) and y = −5.621 + 2.519 × ln(Age) ± 0.146 (R2 = 0.88) for width, y = −9.188 + 0.856 × Age ± 2.174 (R2 = 0.67) and y = −7.570 + 0.768 × Age ± 2.200 (R2 = 0.60) for cross-sectional area, and y = −13.802 + 1.222 × Age ± 1.872 (R2 = 0.84) and y = −11.038 + 1.061 × Age ± 1.964 (R2 = 0.80) for volume, respectively.ConclusionsThe morphometric parameters of vertebra C4 and its three ossification centers show no sex differences. The C4 vertebral body increases logarithmically in height and both sagittal and transverse diameters, linearly in cross-sectional area, and four-degree polynomially in volume. The three ossification centers of vertebra C4 grow logarithmically in both transverse and sagittal diameters, and linearly in both cross-sectional area and volume. The age-specific reference intervals for evolving vertebra C4 may be useful in the prenatal diagnosis of congenital spinal defects.

SummaryBackgroundRapid progress in perinatal medicine has resulted in numerous tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for tracheal dimensions at varying gestational ages.Material/MethodsUsing anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (Wilcoxon signed-rank test, Student’s t test, one-way ANOVA, post-hoc Bonferroni test, linear and nonlinear regression analysis) a range of the 4 variables (length in mm, middle external transverse diameter in mm, proximal internal cross-sectional area in mm2, internal volume in mm3) for the trachea in 73 spontaneously aborted human fetuses (39 male, 34 female) aged 14–25 weeks was examined.ResultsNo significant male-female differences were found (P>0.05). The length ranged from 10.37±2.15 to 26.54±0.26 mm as y=−65.098 + 28.796 × ln (Age) ±1.794 (R2=0.82). The middle external transverse diameter varied from 2.53±0.09 to 5.09±0.42 mm with the model y=−11.020 + 5.049 × ln (Age) ±0.330 (R2=0.81). The trachea indicated a proportional evolution because the middle external transverse diameter-to-length ratio was stable (0.23±0.03). The proximal internal cross-sectional area rose from 1.46±0.04 to 5.76±1.04 mm2 as y=−3.562 + 0.352 × Age ±0.519 (R2=0.76). The internal volumetric growth from 11.89±2.49 to 119.63±4.95 mm3 generated the function y=−135.248 + 9.919 × Age ±10.478 (R2=0.86).ConclusionsThe growth in both length and middle external transverse diameter of the trachea follows logarithmic functions, whereas growth of both its proximal internal cross-sectional area and internal volume follow linear functions. The length and middle external transverse diameter of the trachea develop proportionally to each other. The tracheal dimensions may be helpful in the prenatal diagnosis and monitoring of tracheal malformations and obstructive anomalies of the upper respiratory tract.

BackgroundBoth the advancement of visual techniques and intensive progress in perinatal medicine result in performing airway management in the fetus and neonate affected by life-threatening malformations. This study aimed to examine the 3 tracheo-bronchial angles, including the right and left bronchial angles, and the interbronchial angle, in the fetus at various gestational ages.Material/MethodsUsing methods of anatomical dissection, digital image analysis with an adequate program (NIS-Elements BR 3.0, Nikon), and statistics, values of the two bronchial angles and their sum as the interbronchial angle were semi-automatically measured in 73 human fetuses at the age of 14–25 weeks, derived from spontaneous abortions and stillbirths.ResultsNo male-female differences between the parameters studied were found. The 3 fetal tracheo-bronchial angles were found to be independent of age. The right bronchial angle ranged from 11.4° to 41.8°, and averaged 26.9±7.0° for the whole analyzed sample. The values of left bronchial angle varied from 24.8° to 64.8°, with the overall mean of 46.2±8.0°. As a consequence, the interbronchial angle totalled 36.2–96.6°, and averaged 73.1±12.7°.ConclusionsThe tracheo-bronchial angles change independently of sex and fetal age. The left bronchial angle is wider than the right one. Values of the 3 tracheo-bronchial angles are unpredictable since their regression curves of best fit with relation to fetal age cannot be modelled. Both of the 2 bronchial angles and the interbronchial angle are of great relevance in the location of inhaled foreign bodies, and in the diagnosis cardiac diseases and mediastinal abnormalities.

PurposeKnowledge on the normative growth of the spine is critical in the prenatal detection of its abnormalities. We aimed to study the size of T6 vertebra in human fetuses with the crown-rump length of 115–265 mm.Materials and methodsUsing the methods of computed tomography (Biograph mCT), digital image analysis (Osirix 3.9) and statistics, the normative growth of the T6 vertebral body and the three ossification centers of T6 vertebra in 55 spontaneously aborted human fetuses (27 males, 28 females) aged 17–30 weeks were studied.ResultsNeither male–female nor right–left significant differences were found. The height, transverse, and sagittal diameters of the T6 vertebral body followed natural logarithmic functions as y = −4.972 + 2.732 × ln(age) ± 0.253 (R2 = 0.72), y = −14.862 + 6.426 × ln(age) ± 0.456 (R2 = 0.82), and y = −10.990 + 4.982 × ln(age) ± 0.278 (R2 = 0.89), respectively. Its cross-sectional area (CSA) rose proportionately as y = −19.909 + 1.664 × age ± 2.033 (R2 = 0.89), whereas its volumetric growth followed the four-degree polynomial function y = 19.158 + 0.0002 × age4 ± 7.942 (R2 = 0.93). The T6 body ossification center grew logarithmically in both transverse and sagittal diameters as y = −14.784 + 6.115 × ln(age) ± 0.458 (R2 = 0.81) and y = −12.065 + 5.019 × ln(age) ± 0.315 (R2 = 0.87), and proportionately in both CSA and volume like y = −15.591 + 1.200 × age ± 1.470 (R2 = 0.90) and y = −22.120 + 1.663 × age ± 1.869 (R2 = 0.91), respectively. The ossification center-to-vertebral body volume ratio was gradually decreasing with age. On the right and left, the neural ossification centers revealed the following models: y = −15.188 + 6.332 × ln(age) ± 0.629 (R2 = 0.72) and y = −15.991 + 6.600 × ln(age) ± 0.629 (R2 = 0.74) for length, y = −6.716 + 2.814 × ln(age) ± 0.362 (R2 = 0.61) and y = −7.058 + 2.976 × ln(age) ± 0.323 (R2 = 0.67) for width, y = −5.665 + 0.591 × age ± 1.251 (R2 = 0.86) and y = −11.281 + 0.853 × age ± 1.653 (R2 = 0.78) for CSA, and y = −9.279 + 0.849 × age ± 2.302 (R2 = 0.65) and y = −16.117 + 1.155 × age ± 1.832 (R2 = 0.84) for volume, respectively.ConclusionsNeither sex nor laterality differences are found in the morphometric parameters of evolving T6 vertebra and its three ossification centers. The growth dynamics of the T6 vertebral body follow logarithmically for its height, and both sagittal and transverse diameters, linearly for its CSA, and four-degree polynomially for its volume. The three ossification centers of T6 vertebra increase logarithmically in both transverse and sagittal diameters, and linearly in both CSA and volume. The age-specific reference intervals for evolving T6 vertebra present the normative values of potential relevance in the diagnosis of congenital spinal defects.

PurposeKnowledge on the normative growth of the spine is relevant in the prenatal detection of its abnormalities. This study describes the size of the ossification center of C1–S5 vertebral bodies.Materials and methodsUsing CT, digital-image analysis, and statistics, the size of the ossification center of C1–S5 vertebral bodies in 55 spontaneously aborted human fetuses aged 17–30 weeks was examined.ResultsNo sex significant differences were found. The body ossification centers were found within the entire presacral spine and in 85.5 % of S1, in 76.4 % of S2, in 67.3 % of S3, in 40.0 % of S4, and in 14.5 % of S5. All the values for the atlas were sharply smaller than for the axis. The mean transverse diameter of the body ossification center gradually increased from the axis to T12 vertebra, so as to stabilize through L1–L3 vertebrae, and finally was intensively decreasing to S5 vertebra. There was a gradual increase in sagittal diameter of the body ossification center from the axis to T5 vertebra and its stabilization for T6–T9 vertebrae. Afterward, an alternate progression was observed: a decrease in values for T10–T12 vertebrae, an increase in values for L1–L2 vertebrae, and finally a decrease in values for L3–S5 vertebrae. The values of cross-sectional area of ossification centers were gradually increasing from the axis to L2 vertebra and then started decreasing to S5 vertebra. The following cross-sectional areas were approximately equivalent to each other: for L5 and T3–T5, and for S4 and C1. The volumetric growth of the body ossification center gradually increased from the axis to L3 vertebra and then sharply decreased from L4 to S5.ConclusionsNo male–female differences are found in the size of the body ossification centers of the spine. The growth dynamics for morphometric parameters of the body ossification centers of the spine follow similarly with gestational age.

BackgroundThis study describes reference data for L3 vertebra and its 3 ossification centers at varying gestational ages.Material/MethodsUsing CT, digital-image analysis and statistics, the growth of L3 vertebra and its 3 ossification centers in 55 spontaneously aborted human fetuses aged 17–30 weeks was examined.ResultsNeither sex nor right-left significant differences were found. The height and transverse and sagittal diameters of the L3 vertebral body increased logarithmically. Its cross-sectional area followed linearly, whereas its volume increased parabolically. The transverse and sagittal diameters of the ossification center of the L3 vertebral body varied logarithmically, but its cross-sectional area and volume grew linearly. The ossification center-to-vertebral body volume ratio gradually declined with age. The neural ossification centers increased logarithmically in length and width, and proportionately in cross-sectional area and volume.ConclusionsWith no sex differences, the growth dynamics of the L3 vertebral body follow logarithmically in height, sagittal and transverse diameters, linearly (in cross-sectional area), and parabolically (in volume). The growth dynamics of the 3 ossification centers of the L3 vertebra follow logarithmically in transverse and sagittal diameters, and linearly (in cross-sectional area and volume). The age-specific reference intervals of the L3 vertebra and its 3 ossification centers present the normative values of clinical importance in the diagnosis of congenital spinal defects.

Using anatomical, hydrostatic, and statistical methods, liver volumes were assessed in 69 human fetuses of both sexes aged 18–30 weeks. No sex differences were found. The median of liver volume achieved by hydrostatic measurements increased from 6.57 cm3 at 18–21 weeks through 14.36 cm3 at 22–25 weeks to 20.77 cm3 at 26–30 weeks, according to the following regression: y = −26.95 + 1.74 × age ± Z  × (−3.15 + 0.27 × age). The median of liver volume calculated indirectly according to the formula liver volume = 0.55 × liver length × liver transverse diameter × liver sagittal diameter increased from 12.41 cm3 at 18–21 weeks through 28.21 cm3 at 22–25 weeks to 49.69 cm3 at 26–30 weeks. There was a strong relationship (r = 0.91, p < 0.001) between the liver volumes achieved by hydrostatic (x) and indirect (y) methods, expressed by y = −0.05 + 2.16x  ± 7.26. The liver volume should be calculated as follows liver volume = 0.26 × liver length × liver transverse diameter × liver sagittal diameter. The age-specific liver volumes are of great relevance in the evaluation of the normal hepatic growth and the early diagnosis of fetal micro- and macrosomias.