RU2845024C1 - Method for evaluating formation of human skull sutures - Google Patents

Abstract

FIELD: medical science.

SUBSTANCE: invention refers to medicine, namely to pathological physiology, neurology, X-ray diagnostics. Three equidistant regions are marked on the CT image for the selected cranial suture: S₁ is region on one of ends of suture, S₂ is region in middle of suture, S₃ is region at the other end of suture. Each region includes three points: A is point located on suture line between bone elements, points L and P for bone tissue are points located on both sides of the suture line at a distance of not less than 5 mm. Hounsfield scale is used to measure a bone optical density in points A, L, P for each suture region. Degree of cranial suture healing (E) is calculated for three areas of selected suture by developed formula and average value of selected suture healing E_sut is determined. Obtained E_sut value is used to evaluate seam formation over the entire length.

EFFECT: method enables assessing the timely suture healing, especially at an early age of up to 1.5-2 years, predicting the further development, providing more accurate assessment of suture formation by determining a degree of suture healing.

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Description

The invention relates to medicine, namely to anatomy, pathological physiology and radiation diagnostics, and is intended to assess the formation of the sutures of the human skull.

Untimely fusion of cranial sutures in children at an early age (up to 1.5-2 years) contributes to the development of craniosynostosis. This disease occurs in one out of 2000 newborns and is more often observed in boys (Badalyan L.O. Children's neurology. - M.: Medicine, 1984. - 576 p.).

In terms of the nature of the process, the process of overgrowing of the cranial suture is in many ways similar to the fusion of bone fragments that arise as a result of a fracture, since in both cases two or more bones or fragments are united into one solid structure.

A method for assessing the degree of fusion of tubular bone fractures is known (RU Patent No. 2338463 dated 20.11.2008), based on computed tomography data and dynamic measurement of densitometric indices of the intermediate zone of the regenerate and the cortical layer by determining the bone callus index (BCI). Disadvantages: the method does not allow assessing the degree of healing of the suture or fracture along the line of contact of bones or bone fragments, but only gives an average value.

A method for determining the formation of bone callus by ultrasound compression elastography is known (RU Patent No. 2732705 dated September 21, 2020), which evaluates the deformation coefficient of bone callus. Disadvantages: the method does not allow assessing the degree of healing of a suture or fracture along the line of contact of bones or bone fragments if the ultrasound machine is not equipped with the "Compression elastography" option using linear sensors with a frequency of 8-16 MHz.

A method for determining bone tissue density in vivo is known (RU Patent No. 97103088 of 10.04.1999), which consists of recording changes in the X-ray optical density of the body part being examined in relation to a standard having the X-ray optical density of bone tissue, which is introduced into a removable field near the body part being examined. Disadvantages: the method does not allow one to assess the degree of healing of a suture or fracture along the line of contact of bones or bone fragments without using a standard close in density to bone tissue, and does not offer any parameter that allows one to standardize the assessment of the degree of healing.

A software-digital method for determining the degree of bone fracture healing is known (RU Patent No. 2255656 dated 10.07.2005), based on a quantitative assessment of the difference in optical density (DOD) of the fracture site and the cortical layer of the fracture site. The DOD indicator is used to judge the completion of the consolidation process and express it in digital form. Disadvantages: the method does not determine the gradation of successful and unsuccessful healing, and also offers an indicator that can take values from 0 to infinity from a mathematical point of view, which will complicate the assessment of the correct course of the healing process.

Technical result: increasing the accuracy of determining the formation of cranial sutures based on the introduced coefficient of the degree of overgrowth of cranial sutures; objectifying the method for assessing the overgrowth of cranial sutures.

The specified result is achieved by performing a computed tomography of the head, identifying three equally spaced areas of the selected cranial suture, determining the optical density of bone tissue at three points for each area of the suture, followed by calculating the degree of closure of the selected suture for its three equally spaced areas and calculating the average value of the degree of closure of the selected cranial suture.

The method is implemented as follows: a patient undergoes a CT scan of the head using a 1.5T Brivo 385 CT machine (General Electric - GE Healthcare, USA). On the resulting image, three equally spaced areas are selected for the selected cranial suture: area S ₁ - located at one end of the suture, area S ₂ - in the middle of the suture, area S ₃ - located at the other end of the suture, including three points: point A - located on the suture line between bone elements, points L and P for bone tissue - located on both sides of the suture line at a distance of at least 5 mm from the suture line. According to the Hounsfield scale (Hounsfield GN Computed medical imaging // Medical Physics. - 1980. - Vol. 7, no. 4. - P. 283-290), the optical density of bone tissue (HU) is determined at points A, L, P for each suture area, respectively at points A _S1 , L _S1 , P _S1 , A _S2 , L _S2 , P _S2 , A _{S3, L S3 ,} P _S3 . Next, using the obtained values of the indicators, the degree of fusion of the cranial suture (E) is calculated for three areas of the selected suture - E _S1 , E _S2 , E _S3 using the formulas:

E _S1 = HU(L _S1 ) + 2 HU(A _S1 ) + HU(P _S1 ) / 2 (HU(L _S1 ) + HU(P _S1 )),

E _S2 = HU(L _S2 ) + 2 HU(A _S2 ) + HU(P _S2 ) / 2 (HU(L _S2 ) + HU(P _S2 )),

E _S3 = HU(L _S3 ) + 2 HU(A _S3 ) + HU(P _S3 ) / 2 (HU(L _S3 ) + HU(P _S3 )),

where HU are the values of optical density of bone tissue at points A _S1 , L _S1 , P _S1 , A _S2 , L _S2 , P _S2 , A _S3 , L _S3 , P _S3 .

Next, the average value of the degree of fusion of the selected suture is calculated using the formula: E _suture = ( _ES1 + _ES2 + _ES3 ) / 3, where _ES1 , _ES2 , _ES3 are the degrees of fusion of the cranial suture (E) for three areas of the selected suture _S1 , _S2 , _S3 .

If _{the seam} E value is from 0.5 to 0.74, the seam is not formed along the entire length; if _{the seam} E value is from 0.75 to 1, the seam is formed along the entire length.

The method is based on the results obtained during the examination of 10 patients under 2 years of age with craniosynostosis. To assess the efficiency of the method for determining the formation of human cranial sutures, a comparison with the results of an ultrasound examination was made. Ultrasound examination of the cranial sutures was performed using a Mindray M5 ultrasound machine with a Mindray L14-6s ultrasound sensor with a frequency of 8 to 12 MHz (Shenzhen Mindray Bio-Medical Electronics Co., Ltd; Shenzhen, People's Republic of China). During the comparison, no reliable differences were found between the results of ultrasound diagnostics and similar indicators of the proposed method, the average difference in the results of ultrasound diagnostics and the proposed method was 3.8±1.1%.

Examples of specific implementation

Example 1. Patient V., 12 months old. He consulted a neurologist with seizures. He was sent for a CT scan of the brain. The images were used to determine the optical density of the skull bone tissue in the area of the right frontal suture in three equally spaced areas of this suture, including three points each. The following values of the indicators were obtained: for the region S ₁ HU(L _S1 ) = 441, HU(A _S1 ) = 204, HU(P _S1 ) = 428, for the region S ₂ HU(L _S2 ) = 424, HU (A _S2 ) =175, HU (P _S2 ) = 431, for the region S ₃ HU(L _S3 ) = 412, HU(A _S3 ) = 138, HU(P _S3 ) = 411. The degrees of fusion of the cranial suture (E) were calculated for three regions of the selected suture:

E _S1 = (441 + 2 204 + 428) / (2 (441 + 428)) = 0.73;

E _S2 = (424 + 2 175 + 431) / (2 (424 + 431)) = 0.7;

E _S3 = (412 + 2 138 + 411) / (2 (412 + 411)) = 0.67.

Next, we calculated the average value of the degree of healing of the entire seam: E _seam = (0.73 + 0.7 + 0.67) / 3 = 0.7. According to the proposed assessment, the seam is not formed along its entire length.

Example 2. Patient H., 2 years old. She was observed by a neurologist for six months with complaints of periodic nausea and convulsions. A CT scan revealed signs of craniosynostosis. The optical density values of the skull bone tissue in the sagittal suture area were determined in three equally spaced areas of this suture, including three points each. The following values were obtained:for region S ₁ HU(L_S1) = 640, HU(A_S1) = 498, HU(P_S1) = 627,for region S ₂ HU(L_S2) = 632, HU(A_S2) = 485, HU(P_S2) = 620,for region S ₃ HU(L_S3) = 662, HU(A_S3) = 510, HU(P_S3) = 626. The degrees of cranial suture closure (E) were calculated for three areas of the selected suture:

E _S1 = (640 + 2·498 + 627) / (2·(640 + 627)) = 0.89;

E _S2 = (623 + 2 485 + 620) / (2 (632 + 620)) = 0.89;

E _S3 = (662 + 2 510 + 626) / (2 (662 + 626)) = 0.9.

Next, calculate the average value of the degree of healing of the entire seam: E _seam = (0.89 + 0.89 + 0.9) / 3 = 0.89. In accordance with the proposed assessment, the seam is formed along the entire length.

Example 3. Patient A., 11 months old. He consulted a neurologist with seizures. He was sent for a CT scan of the brain. The images were used to determine the optical density of the skull bone tissue in the area of the left frontal suture in three equally spaced areas of this suture, including three points each. The following values of the indicators were obtained: for the region S ₁ HU(L _S1 ) = 443, HU(A _S1 ) = 122, HU(P _S1 ) = 419, for the region S ₂ HU(L _S2 ) = 423, HU (A _S2 ) = 101, HU (P _S2 ) = 417, for the region S ₃ HU(L _S3 ) = 414, HU(A _S3 ) = 57, HU(P _S3 ) = 410. The degrees of overgrowth of the cranial suture (E) were calculated for three regions of the selected suture:

E _S1 = (432 + 2·122 + 419) / (2·(432 + 419)) = 0.64;

E _S2 = (423 + 2·101 + 417) / (2·(423 + 417)) = 0.62;

E _S3 = (414 + 2·57 + 410) / (2·(414 + 410)) = 0.57.

Next, we calculated the average value of the degree of healing of the entire seam: E _seam = (0.64 + 0.62 + 0.57) / 3 = 0.61. According to the proposed assessment, the seam is not formed along its entire length.

Thus, the proposed method will allow to evaluate the timely healing of the cranial sutures, especially at an early age (up to 1.5-2 years), to predict further development and to objectively solve the problems set before medical specialists.

Claims (7)

A method for assessing the formation of human cranial sutures using instrumental research methods, characterized in that the patient undergoes a computed tomography scan of the head; on the image, three equally spaced areas are distinguished for the selected cranial suture: S ₁ - an area at one end of the suture, S ₂ - an area in the middle of the suture, S ₃ - an area at the other end of the suture, including three points each: A - a point located on the suture line between bone elements, points L and P for bone tissue - points located on both sides of the suture line at a distance of at least 5 mm; according to the Hounsfield scale, the optical density of bone tissue is determined at points A, L, P for each suture area: points A _S1 , L _S1 , P _S1 , A _S2 , L _S2 , P _S2 , A _{S3, L S3 ,} P _S3 ; The degree of fusion of the cranial suture (E) is calculated for three areas of the selected suture - E _S1 , E _S2 , E _S3 , using the formulas: E _S1 = HU(L _S1 ) + 2⋅HU(A _S1 ) + HU(P _S1 ) / 2⋅(HU(L _S1 ) + HU(P _S1 )), E _S2 = HU(L _S2 ) + 2⋅HU(A _S2 ) + HU(P _S2 ) / 2⋅(HU(L _S2 ) + HU(P _S2 )), E _S3 = HU(L _S3 ) + 2⋅HU(A _S3 ) + HU(P _S3 ) / 2⋅(HU(L _S3 ) + HU(P _S3 )), where HU is the optical density of bone tissue at points A _S1 , L _S1 , P _S1 , A _S2 , L _S2 , P _S2 , A _S3 , L _S3 , P _S3 ; then the average value of the degree of healing of the selected suture is calculated using the formula: E _seam = (E _S1 + E _S2 + E _S3 ) / 3, where E _S1 , E _S2 , E _S3 are the degrees of cranial suture fusion in three areas of the selected suture; and with an E _suture value from 0.5 to 0.74, the suture is not formed along the entire length; with an E _suture from 0.75 to 1, the suture is formed along the entire length.