SU1581281A1 - Method of forming image in computer tomography of head - Google Patents

Abstract

This invention relates to the field of medicine. The purpose of the invention is to improve the quality of the visual assessment of images. When imaging each scan, the center of the window (CC) at a constant window width is determined by the average values of absorption coefficients (CP) of the cerebrospinal fluid on sections with the ventricular system of the brain, and in the last such section the reference image element (ELIZ) is selected corresponding to tissues of the sickle process and having constant coordinates on the matrix of all studied sections, and determine its KP. On sections located above the ventricular system of the brain of the central organ, the arithmetic sum of the central organ is obtained, at which an image of the previous section was obtained, and the difference of KP values of the reference ELISA of the studied and preceding sections: Central square of sp. Eliz. Sch.s. - zn.KP ELIZ av. Sr.)

Description

This invention relates to medicine. The purpose of the invention is to improve the quality of visual assessment of images.

The method of imaging in computed tomography of the head is that the imaging of each scan on the display screen by selecting the center

windows (CC) on a nonlinear scale of absorption coefficients (KP) obtained by a CJT survey, the center of the window (CC) at a constant value of its width (SHO) is set in media; the values of the absorption coefficients of the cerebrospinal fluid in sections with the presence of the ventricular system of the brain, and the last section with the presence of the cerebrospinal

fluids choose a reference image element (ELIZ) corresponding to the tissue of the crescent process and having constant coordinates on the matrix of all studied sections, with obtaining a quantitative value of its absorption coefficient (CP) on this section, and on sections located (above the ventricular system of the brain, center the windows are set by the arithmetic sum of the center of the oknd (CO), at which the image of the previous slice is obtained, and the difference of the quantitative values of the KP of the reference ELISA of the studied and previous slice, which corresponds to There is a calculation according to the formula: Ц0 ((3. & p CO "p. cf + + (tn. KP. ELIZA Y3. Cp. - kn. KP. ELIZair. y |.

nm

The method is based on the firmware of the DGP and computer-SM-2, which are part of the scanning X-ray tomograph for examining the CPT-10UOM head.

Graphic halftone display (DGP) provides display of graphic black-and-white information on the screen and operative data exchange in data processing systems, i.e. display of the received information with a specified correspondence between the obtained function values and the shades recorded in the functional converter in the form of firmware

Firmware extinction halftone

25

thirty

(HASHPTON) is intended for quenching of all image elements (ELIZES), produced on the screen in one shade. To implement this function, it is necessary to set the pointer (CURSOR) in the ELIZ on the screen and press the HaschPTON function key, all ELIZs (quenched) induced by the specified shade disappear from the screen, i.e. a single degree of brightness. The degree of brightness of ELIES on the screen is determined by the values of their absorption coefficients calculated during mathematical reconstruction in the CM-2 computer and obtained for analysis using the microprogram Statistical Image Analysis (AID) values differ by no more than +1.2 units. N. According to the data of the SAID microprogram, it is possible to estimate the statistical reliability of the average KP value using mean square otkl. and variance.

 Using the CURSOR function of the DGP, the pointer moves along the screen, respectively, of the X and Y coordinates with the indication of their numerical values in the upper right corner of the screen. Applying the MARKER function, if necessary, ELIES of interest can be noticed. The X and Y coordinates, by their numerical values, which determine the location of the ELISA on the screen, are also basic data for the operation of the SIDF microprogram.

Image formation on the screen

45

50

35

not performed by pkna,

Apply the functions of the DGP center and the width of the window (CO and SHO), the data of which is displayed on the screen in the lower left corner. The change in the color center and the SHO determine the contrast and the degree of brightness of the resulting image, as well as being in a certain functional relationship with the DGP microprogram, which shows the numerical value of the KP in Hounsfield units (units H) in the ELIS in the upper part of the middle of the screen, for example, in the form of 3N 00022 that

is treated as - 22 units,

Functional dependence of this firmware, depending on the parameters of the CO is as follows: if at. the KP value of the image element (,) is equal to -22 units.H, then with this value will be equal to O (3N 00000).

A similar relationship is traced when the SHO changes.

The spatial resolution of the CPT-1000M tomograph is equal to the matrix cell size of 1.5x1.5 mm, since the image is formed on a matrix of 160x160 cells.

The width of the window directly affects the resolution of the tomograph with respect to the density differential;

This feature is resolved; the width of the window remains constant during the formation of images of all sections, for example, equal to 128 units H, and the resolution (at this SHO) of the density difference between ELIESES,

 128

calculated by the formula 7p comp. 40

Vit 3.2 units.I.

The absorption capacity of the tissues and structures of the head is proportional to the average KP value in the image element, which is expressed in Hounsfield units (HU). Therefore, taking into account that the KP values of the cerebrospinal fluid are the closest in density to water, the data on the values of the absorbing capacity of the tissues and head structures on each lake are identified with the average KP values of the spinal fluid obtained using the SARI microprogram with cf. sq. off + +3.2 units H, i.e. within the selected resolution of the density differential scanner. On sections located above the ventricular system of the brain, the values of the absorbing capacity are identified with the CP of the image elements corresponding to the tissue of the sickle process, with t

CO

PR.sr

+ (zn.KP.Eliza

- zn.KP.ELIZa

Pr-Wed

), namely

+ (28-21) 59, if in the formula we substitute the values obtained by the micro

taking into account the values of KP spinal dikkoti on previous sections. If you suspect the presence of calcifications in the tissue of the sickle process, you should use the average values of KP with mean square otkl. no more than ± 3,2 units

The order of operation in the formation of images with the subsequent evaluation is as follows.

1. The image of a slice is shown on the screen of the DGP, the CO is arbitrary but within the nature of the tissues under study. Visually determine the ELISA displaying the spinal fluid and determine its coordinates, the values obtained are entered

in computers and using the SARI firmware, the average KP values of the cerebrospinal fluid are obtained with a mean square no more than +3.2 units.

2. Then the center of the window (CO) is set according to the obtained value of the KP of the cerebrospinal fluid at 1110 12 8.

To control the accuracy of the selected parameters with which. an image is obtained, the HaschPTON firmware is used, and a visual assessment is made of the quenched ELIES that must fill the ventricular system.

This procedure for imaging is carried out with all sections with the ventricular system, and the last section with the presence of the ventricular system produces the following.

3. Visually choose ELISA corresponding to the tissue of the sickle process with obtaining its coordinates

and density values on the screen of BPH. ZN 00021 at. +52; .

4. Image formation of the next studied section (not having a ventricular system) with the values; , which corresponds to the parameters of the previous slice, and the ELIZ-NN 00028 density is determined from the coordinates.

. 5. The results obtained are introduced into the developed formula: TSO I8.Sr

15812816

with the SAIZ program, the CO 52.2 + (80.2 - - 74.5) 57.9, the average error of the average value between the density values entered on the screen of the BPH and the KP values obtained using the SAIZ firmware will be +1 , 1 (t - 1.1).

Claims (1)

Invention Formula The method of imaging with computed tomography of the head, including the choice of the center of the window on a nonlinear scale of absorption coefficients obtained during CT examination, and the formation of images of each scan on the screen display, characterized in that, in order to improve the quality of the visual assessment of images, the formation of images of each slice is carried out in a single halftone the steps of the gradation ability of the display screen at a constant window width for all slices, the center of the window is set according to the average the values of the absorption coefficients of the cerebrospinal fluid on sections with the presence of the ventricular system of the brain, and the last section with the presence of the cerebrospinal fluid, choose a reference picture element (ELIZ) corresponding to the tissue of the crescent process, with a statement of its coordinates on the display matrix and the quantitative value of the absorption coefficient (KP ), then on sections located above the ventricular system of the brain, the center (CO) is established in accordance with the formula window five five C ° out. tf- CO pr.s ,,. + (zn.KP ELIZA - - zn. KP ELIZA Pr.Sr), where is the target center windows when  etc Pr.sr "ENTR which obtained the image of the previous slice; 0 (zn.KP ELIZa "and Wed-zn. KP ELIZA Etc. with ) is the difference between the absorbance values of the reference picture element of the emitted and previous sections.