RU2306104C1 - Method for differential diagnostics of the degree of aortic valve calcinosis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: it is necessary to carry out ultrasound densitometry. While conducting cardiac ultrasound testing upon Nemio 35 (TOSHIBA) diagnostic system for visualization one should apply standard cardiac program (1HeartA), a cardiac sensor - a phased lattice and standard factoryadjustments for obtaining the picture: Gain-80 level, sensor's insonation frequency - 2.5 MHz without applying the 2^nd harmonics. The picture of aortic valve should be withdrawn out of sensor's parasternal position at the section along the short axis. Aortic valve should be outlined by including valvular ring according to ellipse technique. On finishing ultrasound densitometry due to applying 2D-histogram program one should estimate the value of Mean parameter: the value ≤10 indicates the absence of aortic valve calcinosis - the degree 0; Mean value >10 and ≤13 indicates inconsiderable aortic valve calcinosis - the degree 1; Mean value >13 and ≤17 indicates moderate calcinosis - the degree 2; Mean value >17 indicates considerable aortic valve calcinosis - the degree 3. The innovation enables to increase information value and significance of diagnostics.

EFFECT: higher accuracy of diagnostics.

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Description

The present invention relates to medicine and will find application in the ultrasound diagnosis of aortic valve calcification (AS).

Calcification is a disease with an unknown etiology, which is characterized by a progressive thickening of the valves of the aortic valve and the development of calcifications with the subsequent formation of aortic valve stenosis (AK). According to various authors, CAC is among the common pathologies in the elderly and senile age and is detected in 18-21% of people under the age of 70 years and in 48-66% - over 75 years (Gorokhova SG - Clinical gerontology. - 2000 . - No. 3-4. - S. 39-40). The urgency of the problem is explained by the late appeal for medical help, certain difficulties in diagnosis and high mortality in patients with clinical symptoms (shortness of breath, chest pain and fainting).

Currently, a quantitative assessment of the degree of AS is carried out using electron beam computed tomography (Lippert JA et al. Amer. J of Roentgenology. - 1995. - V.164. - No. 1. - p.7377). Calcification of the aortic valve using electron beam computed tomography (CT). CRT is a cross-sectional technique for obtaining high-resolution images that accurately determines the presence and quantifies calcification. The study was carried out in a prone position. 40 axial transverse sections of the heart were obtained during one inspiratory phase of respiration followed by reconstruction with 26 cm image fields. Calcification of the aortic valve was characterized as an area of at least two pixels (area> 0.5 mm) with a density of 130 or more Hudfield units, which refers to the aortic valve. The amount of calcification is calculated using a volumetric indicator. However, the described method has a significant limitation, since not all medical institutions are equipped with such equipment and the method requires highly professional training of the operator.

In the work of I.V. Egorov (Doctor. - 2000. - No. 7. - P.32-34) two-dimensional echocardioscopy was used to detect AS. It provides anatomical visualization of calcifications, in the form of dense echo signals in the ring and proximal sections of AK flaps, and provides information on the anatomical disorders associated with the defect: hypertrophy, dilatation of the heart chambers, and contractile myocardial function. However, the diagnosis is difficult for the reason that the ultrasound picture is usually evaluated purely visually, which makes it impossible to quantify the degree of calcification. In the same work, an X-ray examination was used to detect the petrification of soft tissues of the internal organs and, in particular, the aortic valve. However, at present, the X-ray method is rarely used because of the harmfulness of radiation and the inability to determine the exact genesis of petrification (rheumatic or senile).

The closest analogue in technical essence as a prototype is taken "Method for the quantitative assessment of ultrasonographic images of organs and tissues", application No. 94024339, BIPM No. 22. - 1994. This method involves pointing the sensor at an object, obtaining its image, marking, plotting and analyzing the amplitude histogram with determining the prevailing gradation (gray scale). This method differs from other methods in that when receiving an image of the object: a) the sensor is pointed at a large blood vessel or heart cavity located in the plane of the object, b) mark the image area inside the vessel or cavity, c) determine the maximum power level of the studied signal, in which the prevailing gradation (gray scale) of this section is 1. Then, the amplitude histogram of the object under study is constructed and analyzed at this power level. The weakness of this method is that, based on the determination of the maximum power level of the studied signal, at which the prevailing gradation (gray scale) of this section is 1, it is not possible to differentiate the presence or absence of aortic valve calcification; in this regard, the method cannot be used for differential diagnosis of the degree of calcification of the aortic valve.

The aim of the present invention is to increase the information content and reliability of the diagnosis of calcification of the aortic valve.

This goal is achieved by quantifying the degree of calcification of the aortic valve using ultrasound densitometry. In the position of the patient lying on the left side, the cardiac sensor (phased array) is installed in the third intercostal space to the left of the sternum to obtain an aortic valve image along the short axis. The Nemio 35 (TOSHIBA) is used and the standard program 1 Heart A is turned on; the Gain level is 80, and the insonation frequency of the sensor is 2.5 MHz without the second harmonic. The aortic valve is contoured including the aortic ring using the ellipse method, followed by the inclusion of a calculation program (2D histogram). A histogram appears on the screen with the following indicators: the percentage of the most common image brightness value (Max), the average image brightness value in the entire volume of received data (Mean), standard deviation (SD), and the total number of points that were measured (N). When conducting densitometry, only the Mean indicator is taken into account (the average brightness value in the entire volume of data obtained). With increasing density of the aortic valve during calcification, the average value of image brightness (Mean) also increases. With a value of Mean> 10, the presence of calcification of the aortic valve is diagnosed, and with a value of ≤10 - absence of calcification (degree 0), a value of Mean> 10 and ≤13 indicates a slight calcification of the aortic valve (degree 1), with a value of Mean> 13 and ≤ 17 moderate calcification of the aortic valve (grade 2), with a value of Mean> 17 - significant calcification of the aortic valve (grade 3).

Example 1

Patient M., 60 years old, was admitted to the cardiology department with a preliminary diagnosis: coronary heart disease, stable angina pectoris 3-4 FC NK II A and arterial hypertension 2 degrees, 3 stages. In the position of the patient lying on the left side, a cardiac sensor (phased array) was installed in the third intercostal space to the left of the sternum to obtain an image of the aortic valve along the short axis. In this case, the Nemio 35 instrument (TOSHIBA) was used and the program 1 Heart A was turned on (level Gain 80, the insonation frequency of the sensor 2.5 MHz without the second harmonic). The aortic valve was outlined including the aortic ring using the ellipse method, followed by the inclusion of a calculation program (2D histogram). A histogram appeared on the screen with the following indicators: percentage of the most common value of image brightness (Max - 6.0%), average value of image brightness in the entire volume of received data (Mean-19.90), standard deviation (SD-7.70) , the total number of points that were measured (N-3704). The level of Mean-19.90 indicated the presence of severe calcification of the aortic valve. The drawing shows the results of the study.

Example 2

Patient X., 72 years old, was admitted to the cardiology department with a preliminary diagnosis: coronary heart disease stable angina 2 FC NK I and arterial hypertension 2 degrees, 2 stages. In the patient's position, lying on the left side, a cardiac sensor (phased array) was installed in the third intercostal space to the left of the sternum to obtain an aortic valve image along the short axis. At the same time, the Nemio 35 instrument (TOSHIBA) was again used and the 1 Heart A program was switched on (level Gain 80, insonation frequency of the sensor 2.5 MHz without the second harmonic). The aortic valve was outlined including the aortic ring using the ellipse method, followed by the inclusion of a calculation program (2D histogram). A histogram appeared on the screen with the following indicators: percentage of the most common value of image brightness (Max-7%); the average value of the brightness of the image in the entire volume of the obtained data (Mean-10.46); standard deviation (SD-8.50); total number of points measured (N-4593). Level Mean-10.46 allowed to diagnose the presence of 1 severity of calcification of the aortic valve.

The proposed method was tested in the department of ultrasound diagnostics of the clinic of Rostov State University for 37 patients, which made it possible in each case to determine the severity of calcification of the aortic valve.

Claims (1)

A method for differential diagnosis of the degree of calcification of the aortic valve using ultrasound densitometry, characterized in that when performing ultrasound examination of the heart on the Nemio 35 diagnostic system (TOSHIBA), the standard cardiac program (IHeartA) is used for imaging, the cardiac sensor is a phased array and standard factory settings for image acquisition : Gain-80 level, sensor insonation frequency - 2.5 MHz without the 2nd harmonic; the image of the aortic valve is removed from the parasternal position of the sensor with a cross section along the short axis, the aortic valve is contoured including the valve ring using the ellipse method, and after ultrasonic densitometry using the 2D histogram program, the value of the Mean indicator is evaluated: a value of ≤10 indicates the absence of calcification of the aortic valve - degree 0, Mean value> 10 and ≤13 - indicates insignificant calcification of the aortic valve - degree 1, value Mean> 13-≤17 - indicates moderate calcification of ao Talnoe valve - 2 degree, and a value Mean> 17 - significant calcification of the aortic valve - 3 degree.