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OBSTETRICS AND GYNECOLOGY

INVENTION
Patent of the Russian Federation RU2164082

METHOD OF DIAGNOSTICS OF THE CONDITION OF THE CENTRAL NERVOUS FRUIT SYSTEM

METHOD OF DIAGNOSTICS OF THE CONDITION OF THE CENTRAL NERVOUS FRUIT SYSTEM

The name of the inventor: Bainarovich OV; Fastikovskaya E.D.
The name of the patent holder: Novokuznetsk State Institute of Advanced Medical Education
Address for correspondence: 654005, Kemerovo Region, Novokuznetsk, Stroiteley 5 Avenue, GIDUV, Patent Department
Date of commencement of the patent: 2000.03.07

The invention relates to medicine, namely, to radiation diagnostics (ultrasound examination). The method provides an increase in the accuracy of diagnostics of deviations in the development of the fetal central nervous system. Measurement of the biparental (BPR) size of the fetal head and the transverse diameter of the cerebellum (PMD) at the time from 12 to 35 weeks of pregnancy is calculated, the prognostic factor is calculated as the ratio of BPR / PDM. With a coefficient of 12-14 weeks, equal to 2 (+/- 0.1), the correct formation of the fetal brain is judged. An increase or decrease in the coefficient indicates an abnormal development of the fetal brain, followed by the development of diseases of the central nervous system of the fetus.

DESCRIPTION OF THE INVENTION

(EN) The invention relates to medicine, namely, to radiation diagnostics (ultrasound), and is used in obstetrics and gynecology.

Anomalies in fetal brain development are 10 -30% of all developmental malformations and occupy one of the first places in their structure.

Detection of the developmental defects of the central nervous system of the fetus is perceived by clinicians as a situation with an unambiguously poor prognosis for the life and psychomotor development of the unborn child. Diagnostic data on the possible presence of any defects of the central nervous system of the fetus actively affects obstetric tactics (abortion or prolapse with delivery by operation - caesarean section).

A method for diagnosing the developmental defects of the central nervous system of the fetus is known by determining the cephalic index. The cephalic index is calculated from the ratio of the biparietal size of the fetal head (BDP) to the frontal-occipital size (LZR), multiplied by 100% (BPR / LZR x 100%).

Normally, its limiting value ranges from 71 to 87%, so a value of less than 71% indicates dolichocephaly, and more than 87% - about brachycephaly (Clinical Guidelines for Ultrasound Diagnostics, Volume N 2, Moscow, Vidar, 1996, Article 33 -34, MV Medvedev, VV Mitkov). However, this formula has a number of drawbacks, for example, in the pelvic presentation of the fetus, the dolichocephalic shape of the head is often found. In cases of dolichocephaly and brachycephaly, the numerical values ​​of BDP are often found at the border of individual fluctuations in the norm and do not adequately assess the conformity of the fetal head to the term of pregnancy.

It is known to study the intrauterine growth retardation (Journal of Obstetrics and Gynecology N 8-12, 1992, "Ultrasonic diagnosis of intrauterine growth retardation" NV Strizhova, Hisham Yasin Mohamed Elamin, IS Bokin). In this method, the measurement of the transverse diameter of the cerebellum is used to determine gestational age. The expediency of studying this parameter is due to the fact that the size of the cerebellum of the fetus is not affected by pathological processes affecting the development of all organs and systems of the fetus. The cerebellum is well protected and it reacts least of all to changes in blood flow. Thus, with a deviation of the fetometric parameters, the diagnosis of fetal development retardation is less than the norm and the normal size of the cerebellum (corresponding to the gestational age of the fetus). However, these studies do not take into account the anomaly of the development of the cerebellum: hypoplasia, Dandy-Walker syndrome (absence of a cerebellum worm with a decrease in the size of the cerebellum), Arnold-Chiari syndrome (anomalies in the development of the cerebellum when it is inserted into the large occipital orifice).

The closest, taken as a prototype, is the method of expanded fetometry with the calculation of the ratio of the transverse diameter of the cerebellum (using tables) to the circumference of the fetal head (using the size of the fetal head circumference, respectively, the gestation period). This method was used to identify the ultrasound marker of chromosome defects of the fetus ("Ultrasonic markers of chromosomal defects of the fetus", Moscow, VIDAR, 1997. RJM.M. Snyders, K.K. Nikolaides).

Disadvantages of this method

1. Absence of a connection between the violation of the ratio of the transverse diameter of the cerebellum to the circumference of the head with a certain pathology of the central nervous system. The reasons for the decrease in this ratio and the increase in this ratio are not known.

2. The impossibility of using this method in the early stages of pregnancy, since the calculation of this ratio is carried out from 14 weeks, and the visualization of the cerebellum by a transvaginal sensor is possible from 12 weeks of pregnancy (interruption of pregnancy to 12 weeks is less dangerous for a woman's health than an interruption in a late period) .

It is an object of the present invention to improve the accuracy of diagnosing deviations in the development of the central nervous system of the fetus.

The task is achieved by measuring the biparietal (BPR) size of the fetal head and the transverse diameter of the cerebellum (PMD) in the period from 12 to 35 weeks of pregnancy, calculate the prognostic ratio as the ratio of BPR / PDM. If the coefficient of 12-14 weeks is equal to 2 (+/- 0.1), and in 15-35 weeks is equal to 2.3 (+/- 0.1), the correct formation of the fetal brain is judged. An increase or decrease in the coefficient indicates an abnormal development of the fetal brain, followed by the development of diseases of the central nervous system of the fetus.

Novelty of the method

1. The ratio of BPR / PDM is reliable, as the rates for the norm from 12 to 14 weeks were 2, and at the time from 15 to 35 week corresponded to 2.3. The period from the 36th week was not taken into account, as the size of the fetus varies over a wide range in accordance with its constitution. The separation of the two coefficients is due to the fact that, starting from the period of 14 weeks, there is an active development of the mass and volume of the brain.

2. Indicators BDP and PDM are selected from a practical study. The arithmetic mean values ​​of BPR and PDM were used according to the gestation period.

3. Deviation of the coefficient below the norm indicates a decrease in the size of the head - microcephaly, dolichocephaly, fetal development retardation syndrome. The increase in the coefficient occurs with a decrease in the size of the cerebellum - hypoplasia, Dandy-Walker syndrome (absence of the cerebellum worm with a decrease in the size of the cerebellum), Arnold-Chiari syndrome (anomalies of the cerebellum development when it is attached to the large occipital foramen), and with an increase in the size of the fetal brain ( Hydrocephalus), normal PDM.

4. Using the ratio of BPR / PDM allows you to diagnose the aforementioned diseases of the fetus at earlier stages of pregnancy, as there is a certain dependence of the growth of brain structures at all stages of development of the central nervous system of the fetus. The study of the structure of the brain in the period of 12-14 weeks showed that the cerebellum is formed and clearly visualized. The large hemispheres of the brain are just beginning to form, thus, BPD is most dependent on properly formed lateral ventricles of the brain, intermediate and median brain. From this it follows that in the abnormal development of the fetal brain the prognostic coefficient will deviate from the norm.

The essence of the method is as follows: the pregnant woman is placed on her back, for diagnosis, a transabdominal convection sensor of 7.5 MHz and a transvaginal sensor of 5 MHz are used. Transvaginal examination is used in the period of 12-14 weeks, low position of the fetal head and with increased nutrition of the woman (in the head presentation of the fetus). In other cases, a transabdominal test is used. A multiplanar technique for scanning the fetal head is used. For the study of BDP used horizontal slice through the cavity of the transparent septum, thalamuses, the third ventricle, and the frontal horns, the posterior parts of the ventricles and the occipital horns. For the study of the cerebellum, cuts are taken: in the horizontal plane, the cut passes through the cerebellum and the fourth ventricle; In the sagittal plane, the cut passes through the interhemispheric fissure, the middle part of the corpus callosum, the third ventricle, the cerebellar worm and the large cistern; In the frontal plane, the cut passes through the hippocampus and the fourth ventricle. A horizontal plane is used to measure the transverse diameter of the cerebellum (PDM).

To calculate the prognostic coefficient, the BPR / PD ratio is used, which is calculated for each term. Data are recorded in the pregnant card for dynamic observation (see table).

For practical use, it is advisable to separate the two coefficients depending on the level of ultrasound screening:

1) the level is 12-14 weeks (coefficient 2),

2) the level is 15-35 weeks (coefficient 2.3),

Which are taken as the norm, i.е. The development of the fetal brain goes without deviations.

Taking into account individual fluctuations in the fetometric parameters, the variability of the coefficient +/- 0.1 is permissible.

The difference between the norms in the period from 12 to 14 weeks and in the period from 15 to 35 weeks is due to the fact that at the first level there is no active growth of the cerebral hemispheres, the intensive development of the intermediate, median and terminal parts of the brain follows. At the second level, the increase in the large hemispheres is associated with the formation of the cerebral cortex. Therefore, at the first level, the BDP increases somewhat more slowly than at the second level. Based on these features of the development of the brain, two coefficients are derived. Reduction in the coefficients occurs with a decrease in the size of the fetal brain. An increase in the coefficients follows with a decrease in the size of the cerebellum, or with an increase in the volume of the fetal brain with an unchanged cerebellum.

The proposed method allows predicting the syndrome of fetal development delay, brain pathology (Dandy-Walker, Arnold-Chiari II with hydrocephalus III st, occipital encephalocele, cerebellar hypoplasia, chromosomal diseases with head shape change, neoplasms) from 12 weeks of pregnancy. This could not be done using similar methods. The accuracy of this forecast model is 96% according to our results.

The method can be applied in practical perinatal ultrasound diagnostics in conjunction with traditional methods of studying the central nervous system of the fetus.

Comparison of the claimed method with the available ones made it possible to establish compliance with the criterion of "novelty".

Example 1 . Pregnant A., 18 years old.

DZ: Pregnancy is 14 weeks.

BPR - 26 mm, PDM - 13 mm. The forecast coefficient is 2.

During pregnancy, a screening ultrasound study showed no deviations in the development of the central nervous system. Childbirth occurred within a period of 38 weeks without complications, a full-term fetus (8-9 points on the Apgar scale). Examination of a neurologist: DZ is healthy.

Example 2 . Pregnant P., 30 years old.

DZ: Pregnancy is 13 weeks.

BPR - 24 mm, PDM - 10 mm. The predictive factor is 2.4.

Visually, the pathology of the brain is not revealed. With a dynamic examination at 16 weeks, the defect of Arnold - Chiari II was discovered. BPR - 37 mm, PDM - 14 mm. The predictive factor is 2.6. In the period of 20 weeks: BPR - 49 mm, PDM - 18 mm. The forecast coefficient is 2.7.

Pregnancy is interrupted. DZ is confirmed pathoanatomically.

Example 3 . Pregnant L., 37 years old.

DZ: Pregnancy is 14 weeks. Occipital meningocele, ascites, hydrothorax, hyperechoic gut syndrome.

BPR - 26 mm, PDM - 10 mm. The predictive factor is 2.6.

Pregnancy is interrupted, DZ is confirmed pathoanatomically.

Example 4 . Pregnant A., 30 years old.

DZ: Pregnancy is 13 weeks. Syndrome of amniotic cords. Dolichocephalic shape of the head.

BPR - 20 mm, PDM-12 mm. The predictive factor is 1.6.

Pregnancy is interrupted, DZ is confirmed pathoanatomically.

Thus, the method of diagnosing the state of the central nervous system of the fetus by calculating the prognostic factor combines the high informativeness, simplicity and efficiency of obtaining information about the development of the fetal brain, harmlessness, and the absence of contraindications.

The method is used in a prenatal ultrasound study, when screening pregnant women to study the state of the central nervous system of the fetus.

CLAIM

A method for diagnosing the condition of the fetal central nervous system, including ultrasonic fetometry of the fetal head, characterized by measuring the biparietal size of the head and the transverse diameter of the cerebellum from 12 to 35 weeks of gestation, calculating the prognostic factor as the ratio of BPR / PDM, with a coefficient of 12 - 14 weeks, equal to 2 (+/- 0,1), and in 15-35 weeks equal to 2,3 (+/- 0,1), judge the correct formation of the fetal brain, with a decrease or increase in relation to normal values Coefficients, judge the abnormal development of the fetal brain with the subsequent development of diseases of the central nervous system.

print version
Date of publication 27.03.2007gg