RU2792815C1 - Method for predicting the risk of bleeding in women during delivery in case of placenta ingrowth into myometrium - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to radiation diagnostics in obstetrics and gynecology, and can be used to predict the risk of bleeding in women during delivery in case of placenta ingrowth into the myometrium. At 33-36 weeks of gestation, magnetic resonance imaging (MRI) is performed in the sagittal plane. In the area of the lower uterine segment, by tracing the area including the myometrium and the adjacent placental tissue, a zone is identified that is suspicious of the ingrowth of the chorionic villi into the myometrium, corresponding to a non-uniform decrease in the MI signal by T2 WI. The maximum (I _max) and minimum (I _min) value of the intensity of the MI-signal is determined and the coefficient of inhomogeneity (k) is calculated using the formula k=Imin\Imax*100%. With a value of k up to 15% inclusive, a high risk of bleeding is predicted. With a value of k more than 15%, a low probability of bleeding is predicted.

EFFECT: method allows to predict the risk of bleeding in patients with placenta ingrowth and to identify risk groups by determining the coefficient of heterogeneity.

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Description

The present invention relates to medicine, namely to radiation diagnostics in obstetrics and gynecology, and can be used to predict delivery tactics in pregnant women with placenta previa.

Placenta ingrowth is one of the extremely serious complications of pregnancy, associated with the risk of massive uterine bleeding. The frequency of occurrence of this pathology over the past 50 years has increased by about 10 times [E. Jauniaux, et al 2018]. The increase in cases of true placenta ingrowth is associated with an increase in the number of operative deliveries. [N.S. Bartels et al 2018].

The following types of pathological attachment of the placenta are distinguished [E.E. Jauniaux et al 2018]:

- attachment of placenta accreta (attachment of the placenta occurs in the basal layer of the endometrium);

- placenta increta (when there is no spongy layer between the muscle layer and the villi and the villi reach the muscle layer);

- germination of the placenta percreta (villi of the chorion penetrate deeply into the muscle layer, often penetrate the myometrium, parametria with invasion into neighboring organs).

The last two types are characterized by a high risk of developing massive postpartum hemorrhage and require a multidisciplinary approach to delivery. Studies by Fitzpatrick et al [2014] and Bowman et al [2014] showed that the diagnosis of placental attachment pathology is not established in the prenatal period in half or a third of all cases of this pathology. In this regard, antenatal diagnosis of true placenta ingrowth is of great importance, which is necessary for choosing the most rational tactics for further management of pregnancy and delivery. Many authors suggest that MRI, in comparison with ultrasound, more clearly defines the area of pathological attachment of the placenta, clarifies the degree of invasion and, ultimately, affects the tactics of surgical treatment, so MRI should be used routinely in this pathology. [Pomortsev A. IN. et al., 2018, Kanter G., Packard L. Et all., 2013].

A known method for assessing the depth of invasion of chorionic villi into the myometrium in pregnant women with a scar on the uterus after cesarean section, including an assessment of the border between placental tissue and myometrium on MRI, as well as an assessment of the contours of the uterine wall on MRI. [Pomortsev A.V., Khudorozhkova E.D., Matosyan M.A., Makukhina T.V., Nosulya I.G. Radiation diagnosis of placenta ingrowth in pregnant women with a scar on the uterus after caesarean section. Kuban Scientific Medical Bulletin. 2018; 25(3): 97-106]

The purpose of this study was to determine significant markers of ultrasound and magnetic resonance imaging in diagnosing the depth of chorionic villus invasion into the myometrium in pregnant women with a uterine scar after cesarean section, which, as a result, allows you to determine the tactics of managing pregnancy and childbirth and reduce the risk of developing complications in this category of patients.

The disadvantages of this method is the long time of the study and the lack of a unified indicator of pathological attachment.

As the closest analogue, the method "Possibilities of MRI in the diagnosis of placental anomalies" was taken [Luzhetskaya A.A., Gustovarova T.A. POSSIBILITIES OF MRI IN THE DIAGNOSIS OF PLACENTA ANOMALIES // Smolensk Medical Almanac. 2021], which collected and analyzed data from MP-examination of the pelvic organs of patients for the presence of placental anomalies, such as placenta previa and placenta ingrowth. Based on the results of the study, it was concluded that MRI allows obtaining the most complete clinical picture and adjusting the patient management plan in order to minimize blood loss during delivery.

The disadvantages of this method: the long time of the study, the lack of determination of the risk of bleeding during delivery, the lack of clear criteria for determining the tactics of delivery.

Objectives of the invention:

- calculation of the ratio of the intensity of the MP-signal in the area suspected of placenta ingrowth;

- reduction of examination time;

- predicting the degree of risk of bleeding during delivery;

- increasing the reliability of forecasting results;

- determination of delivery tactics, taking into account modern organ- and blood-saving technologies.

The essence of the invention: MRI in T2 WI mode in the sagittal plane and in the region of the lower uterine segment by tracing the zone, including the myometrium and the adjacent placental tissue, reveals a zone suspicious for the ingrowth of chorionic villi into the myometrium, corresponding to a non-uniform decrease in the MP signal according to T2 WI, automatically obtaining the maximum (Imax) and minimum (Imin) values of the intensity of the MP signal, then calculate the coefficient of inhomogeneity (k) by the formula

and with a value of k up to 15% inclusive, a high risk of bleeding is predicted, with a value of k more than 15%, a low probability of bleeding is predicted.

Thus, the proposed method has the following technical result:

- the method allows to determine the ratio of the intensity of the MP-signal in the area suspected of placenta ingrowth;

- allows to increase the reliability of the results of predicting the risk of bleeding during delivery;

- allows you to form groups according to the degree of risk in order to determine the tactics of delivery of the patient;

The method was tested by the method of prospective observation and retrospective analysis of the histories of 72 pregnant women from the 33rd to the 36th week of gestation with a scar on the uterus after caesarean section.

In a study of 72 (100%) women, 48 (66.7%) had a high risk of bleeding, 24 (33.3%) had a low risk of bleeding.

The method is carried out as follows: Pregnant women in the period of 33-36 weeks, having previously obtained informed consent, in the supine position, MRI is performed in the T2 VI mode in the sagittal plane and in the region of the lower uterine segment by tracing the zone, including the myometrium and the adjacent placental tissue, a zone suspicious of chorionic villus ingrowth into the myometrium is identified, corresponding to a non-uniform decrease in the MP signal according to T2 WI, automatically obtaining the maximum (Imax) and minimum (Imin) values of the MP signal intensity, then the coefficient of heterogeneity (k) is calculated using the formula

and with a value of k up to 15% inclusive, a high risk of bleeding is predicted, with a value of k more than 15%, a low probability of bleeding is predicted.

Example 1

Patient K., 36 years old, pregnancy 33-34 weeks, with a history of 2 planned caesarean sections, was sent for a planned MRI, which revealed: the placenta is attached along the anterior wall, in the sagittal section in the T2 WI mode in the lower uterine segment, the area was verified suspicious for ingrowth, and by circling the zone, including the myometrium and the adjacent placental tissue, corresponding to a non-uniform decrease in the MR signal according to T2 VI, in which the minimum intensity is 153, the maximum is 1026.

According to the formula

calculated coefficient of heterogeneity k=153\1026* 100%=14.9%, which corresponds to a high risk of bleeding. In relation to the patient, the tactics of planned delivery in the conditions of an X-ray operating room were used, with the implementation of embolization of the iliac arteries. During the operation, deep ingrowth of the placenta into the uterine wall was revealed, which required metroplasty. At the same time, the intervention was accompanied by a rather high blood loss (2500 ml), which was corrected during the operation and in the early postoperative period. The patient was discharged home in a stable condition on the 10th day of the postoperative period. At the same time, delivery in a conventional operating room would lead to a much more massive one, which would directly threaten the woman's life and could require a longer stay in the hospital, including in the intensive care unit.

Example 2

Patient V., 35 years old, 35-36 weeks pregnant. In the anamnesis - 2 planned CS. The placenta is attached to the anterior wall. In the sagittal section in the T2 VI mode, a zone suspicious for ingrowth was verified, in which the minimum intensity is 165, the maximum is 1100.

According to the formula

coefficient of heterogeneity k=165\1100* 100%=15%,

which corresponds to a high risk of bleeding. The patient underwent a planned cesarean section in an X-ray operating room, with embolization of the uterine arteries. The ingrowth of placental tissue into the myometrium revealed during the operation required metroplasty. The volume of blood loss was 1500 ml, which is significantly lower than when performing such manipulations in a conventional operating room, without tourniquet hemostasis. The patient was discharged home in a stable condition on the 12th day of the postoperative period.

Example 3

Patient T., 33 years old, pregnancy 33-34 weeks. In the anamnesis - 1 planned CS. The placenta is attached to the anterior wall. In the sagittal section in the T2 VI mode, a zone suspicious for ingrowth was verified, in which the minimum intensity is 285, the maximum is 1887.

According to the formula

coefficient of heterogeneity k=285\1887* 100%=15.1%, which corresponds to a low risk of bleeding. In relation to the patient, the tactics of planned conservative delivery in a conventional operating room was applied, blood loss was 700 ml, which corresponds to the standard blood loss with such an intervention.

Claims (3)

A method for predicting the risk of bleeding in women during delivery in case of placental ingrowth into the myometrium, including determining the zone of pathological placentation using magnetic resonance imaging (MRI), characterized in that at 33-36 weeks of pregnancy, MRI is performed in T2 WI mode in the sagittal plane and in the area of the lower uterine segment, by tracing the zone, including the myometrium and the adjacent placental tissue, a zone is identified that is suspicious of the ingrowth of the chorionic villi into the myometrium, corresponding to a non-uniform decrease in the MP signal according to T2 WI, automatically obtaining the maximum (I _max ) and minimum (I _min ) the value of the intensity of the MP signal, then calculate the coefficient of heterogeneity (k) according to the formula

and with a value of k up to 15% inclusive, a high risk of bleeding is predicted, with a value of k more than 15%, a low probability of bleeding is predicted.