ELECTRICAL IMPEDANCE COMPUTER MAMMOGRAPHonkocet.eu/download/MEIK user guide.pdf · The electrical impedance computer mammograph “МEIK”, which operation is based on the method

ELECTRICAL IMPEDANCE

COMPUTER MAMMOGRAPH

“МEIK”

USER'S GUIDE

Part 1

Yaroslavl 2006.

User’s guide Part 1

Electrical impedance computer mammograph “МEIK”

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The device has been manufactured on the basis of the patent of the Russian Federation № 2153285 of 27.07.2000. (Priority of 21.12.1998). Being the most up-to-date medical diagnostic piece of equipment, it features high scientific, medical and industrial potential of companies and institutions, which took part in its fabrication and testing. PKF «SIM-tekhnika», ltd. would like to express its sincere gratitude to:

• Institute of Radiotechnology and Electronics of the Russian Academy of Science

• Russian Scientific Centre for Radiology and Nuclear Medicine of the Public Health Ministry of the Russian Federation, Moscow

• Russian Association “Epidbiomed” of the Public Health Ministry of the Russian Federation, Moscow

• Clinical Hospital № 9, Yaroslavl

• Regional Oncology Dispensary, Yaroslavl

• State Medical Academy, Yaroslavl

• “Yaroslavlsky Radio works”, Inc

• “Watch Factory Chaika”, Inc., Uglich

• Technology Commercialization International, Inc., Albuquerque, NM, USA

Manufacturer: PKF«Modern Impedance Medical Equipment», ltd, INN 7606044489, State Registration #. 1027600843368 Manufacturer’s address: Russia, 150054, Yaroslavl ul. Chkalova, 2, Office 908. For information contact: phone/fax: +7(4852) 795867 e-mail: [email protected], telex 217146 «БАЗИС». ® All rights reserved. No part of this guide can be reproduced or utilized in any form or by any means without permission in writing from PKF «SIM-technika». © PKF «SIM-technika», 2006

TABLE OF CONTENTS

Brief description of the device ............................................................................................. 4

Method of scanning…………………………………………………………………………5

1. Setting-up procedures ..................................................................................................... 5

2. Preparation of patient ..................................................................................................... 6

3. Scanning procedure ........................................................................................................ 8

4. Reconstruction of images ............................................................................................... 8

5. 3–D view of an electrical impedance mammogram ....................................................... 9

6. Data retention ............................................................................................................... 12

7. Using previously saved data…………………………………………..……………....12

8. Using the function for automatic data evaluation ......................................................... 12

9. Operation in the double-window mode………………………………………………13

10. Work completion ..................................................................................................... 166

Software………………………………………………………………………….…….….16

General computer requirements …………………………………………………….…..16

Software installation………………………………………………………………….…16

Programme handling……………………………………………………………….........16

Double-window viewing…………………………………………………………...……...19

Control items…………………………………………………………………………….19

Commentaries to comparison operations……………………………………………......21

Additional options……………………………………………………………………....21


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Brief description of the device

The electrical impedance computer mammograph “МEIK”, which operation is based on

the method of electrical impedance tomography, is intended for imaging and diagnostics of

pathological changes of the mammary glad tissue as well as other near-surface regions of the

body. It is a well-established fact that many tumours, specifically malignant growths of a

mammary gland, are characterized by electro conductivity (ability to conduct electric current),

which significantly differs from electro conductivity of surrounding healthy tissues.

The electrical impedance computer mammography makes it possible to visualize distribution

of electro conductivity of biological tissue in various transverse sections of a patient’s body

and detect such growths on the obtained images. The key advantages of the electrical

impedance methods of diagnostics are: absolute safety of examination, high degree of self-

descriptiveness, connected with considerable correlation of electro conductivity (electrical

impedance) of biological tissues with their physical state, compactness and reasonable cost of

the equipment, simplicity of the examination procedure. The device possesses significant

advantages when compared with the systems, utilizing two-dimensional mapping of electro

conductivity. Such systems are unable to provide spatial resolution in depth. Besides, the skin

state (scratches, birthmarks, degree of moistening) can influence the image to a substantial

extent. The “MEIK” system utilizes the approach, based on solution of the inverse problem

for Maxwell's equation in quasi-static approximation. Thanks to this method it has become

possible to reconstruct the three-dimension distribution of electro conductivity (in form of

tomographic cross-section at different depth) and obtain more detailed images of better

quality). The current concept of measurement renders the visualization result practically

insusceptible to the state of the skin surface.

During the scanning process the device, utilizing one out of 256 electrodes of the matrix

successively injects into the patient’s body weak alternative electric current (0,5 mA) with the

frequency of 50 kHz and registers corresponding distributions of electric potentials on its

surfaces. The obtained data are used then for reconstruction of the electro impedance images

with the help of the mathematical algorithms utilizing a personal computer to which the

device is connected vie the USB port. The device comprises: the diagnostic block with the

built-in microprocessor control system; the two-piece cylindrical electrode, one section of

which is used as a common electrode of the current source and the second one - as a reference


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electrode for measurements of potentials. The diagnostic block is powered via the standard

USB-port. In order to provide safety the data transmission line as well as the power line has

galvanic isolation. The main components of the mammograph are shown in Figure 1.

Figure 1

Note. Due to improvement and development of the electrical impedance computer

mammograph (“МEIK”) the manufacturer reserves the right to introduce changes into the

device design or its software. In order to obtain any information concerning updating of the

software as well as documentation you are welcome to visit the website of PKF

“SIM-tekcnika” ltd at http://www.impedance.ru.

Method of scanning

1. Setting-up procedures

1.1. Connect the device to a personal computer with the help of the cable, connecting it to the

available USB port. Connect the auxiliary cylindrical electrode to the device via the

corresponding connector (Figure 2).


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Figure 2

1.2. The green indicator on the top panel of the mammograph will signify that the properly

installed software in the computer is available and the device is ready for taking

measurements.

1.3. Initiate the programme “MEIK”.

1.4. At the first start of the program and at the beginning of every month the programme will

suggest changing the directory of the current archive, in which the result of the next

measurements will be stored. The purpose of it is to optimize data manipulation since the

large volume of records, stored in one directory can considerably slow down the programme

operation as well as hinder record retrieval. In case the user gives his consent he is offered a

new directory with the name looking like mm_yyyy, where mm and yyyy are the current month

(1 or 2 digits) and year (4 digits).

2. Preparation of patient

2.1. The patient should be in a standing or supine position.

2.2. Select the menu-item Device/Measure, fill the fields of the form, which describe

measurement conditions and press the button Start. The device will switch over to the standby

mode, followed by a blinking yellow indicator on its top panel.

2.3. Moisten liberally the patient’s palm. Place the auxiliary cylindrical electrode into the

patient’s hand in such a way that both parts of the electrode contacted the moisturized skin

areas.


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2.4. Clean the mammary gland under examination with a disposable cleansing tissue and

moisturise it with clean tap water. Although the skin must become saturated with water, there

should be no damp patches or drops on its surface. There is a light-emitting diode (LED) built

into the electrodes panel, the light spot of which helps to achieve precise positioning of the

matrix centre on the required part of the patient’s body. Place the device against the mammary

gland in such a way that as many electrodes as possible contact the skin and press the device

in the direction of the ribs (Figure 3). The image on the computer screen will represent a

dynamic map of the contacts; green colour represents good contacts and black – poor ones.

Slightly altering the device position, try to achieve maximum green area on the image.

Presence of black spots (poor contacts) is not acceptable.

Figure 3

Note. In order to match the upper and the lower parts of the images on the screen with the

direction “head-feet” of the patient, position the device in such a way that the side with the

connecting cables was directed towards the patient’s feet.


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3. Scanning procedure

3.1. Press the button on the device handle. The device will initiate the process of measuring.

The procedure lasts about 20 seconds. During this period it is not allowed to alter the device

position on the patient’s body. During the process of measurement the yellow indicator on the

top panel of the device stays continuously on. If more than 128 poor contacts have been

discovered during the measurement, the procedure will be interrupted, and the appropriate

message will appear on the display.

Note. The measuring procedure can be initiated without activating the control button on the

device – one can start pressing the button Start on the window of contacts dynamic map.

3.2. After completion of the measuring procedure the device is to be placed onto a special rack

and the cylindrical electrode into a corresponding holder. .

4. Reconstruction of images

4.1. If the measuring procedure is successful, the process of images reconstruction will be

initiated automatically. If poor contacts have been discovered during the measurement, the

appropriate message will appear on the display before reconstruction. The process of

reconstruction lasts about 30 seconds on the computer with the processor Pentium 4800 MHz

class.

4.2. The window, displaying the progress of reconstruction, contains a small image – “integral

view” (Figure 4), available also when the menu Viewing/Integral view is chosen. It allows the

user to evaluate location and size of the areas with insufficient contacts of the electrodes with

the patient’s body. It is possible to terminate the process of reconstruction before it reaches its

end.


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Figure 4

5. 3–D view of an electrical impedance mammogram.

At completion of the reconstruction procedure 7 images appear in the programme window,

which correspond to the body cross-sections parallel to the plane of the electrodes placements,

with depth ascending from 0.4 to 4.6 cm (Figure 5). As a rule the mammary gland nipple is

the object, which can be observed practically on all cross-sections and which can be used for

location of coordinates on the impedance images. Malignant tumours can be usually observed

on the images as light spots, positioned asymmetrically around the nipple.

Figure 5

A window with additional information (depth, cursor’s coordinates, electric conductivity in

specific point, Figure 6) is opened when the mouse is clicked on any image.


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Figure 6

Selection of the menu-item Viewing/View 2 will allow you to obtain 7 images, corresponding

to the body cross-section in respect of depth (Figure 7).

Figure7

Clicking the mouse on various levels in the left part of the window, the user will have the

possibility to obtain measurements of the mammary gland conductivity in respect of depth

(Figure 8).


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Figure 8

Having chosen the item Viewing/Highlight Area, one can highlight the field, which

conductivity is of interest to the user. (Figures 9, 10).

Figure 9

Figure 10


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There are some more useful functions for data mapping adjustment in the menu Viewing.

6. Data retention

In order to retain the measurements result, select the menu-item File/Save. Select the patient’s

code from the pulldown list or, if necessary, use the button New for creation of a new

computer account. A text commentary can be added to the saved data.

7. Using previously saved data

In order to gain access to the data, which had been saved before, use the menu-item

File/Select Patient and specify the patient’s code, and after that the required frame (saved

data) (Figure 11, 12).

Figure 11

Figure 12

In order to select other data for the same patient, use the menu-item File/Load and select the

specific saved change. .

8. Using the function for automatic data evaluation

After selection of the menu-item File/Information…there appears the panel, containing

information about the patient and the current file with data (Figure 13). In the bottom line of

this window with the header “Probability” there appears a number, indicating evaluation of


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probability of malignant tumour evidence in the specific mammary gland, obtained with the

help of a statistic regression model

Figure 13

If “Probability” is equal or exceeds 0.5, the patient should undergo additional examination.

Possible tumour site and its size can be estimated visually, analyzing the tomographic image.

9. Operation in the double-window mode

9.1. Select the menu-item Tools/Double-window viewing. The window with two images will

be opened. (Figure 14).


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Figure 14

9.2. Highlight the mammary gland image without artefacts in the left window (left mammary

gland). Do the same in the right window (right mammary gland). Start highlighting from the

left upper corner, holding down the left mouse button. (Figure 15).

Figure 15


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9.3. Select the menu-item Comparison/Left-Right. Compare the electroconductivity frequency

distribution curves of the left and the right mammary glands (histograms). Statistical data for

every image are displayed in the table (above the curve) (Figure 16).

Figure 16

9.4. Select the menu-item Comparison/View of Comparison 2, and then Comparison/Left-

Right. The window with smoothed frequency distribution of the left and right mammary gland

electroconductivity will appear (Figure 17).

Figure 17


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10. Work completion

Terminate the programme utilizing the standard Windows interface facilities or the menu-item

File/Exit.

Software

General computer requirements

Before the software installation make certain that the computer meets the following

requirements:

1) Processor Intel Pentium with the clock rate of 450 MHz and over (or compatible);

2) Working memory; meeting requirements of the operational system installed on the

computer.

3) Hard disk free space not below 200 МB;

4) Available USB port;

5) Video display card, supporting the mode “High Colour” (16 bit) or over;

6) Operational system – WINDOWS 9X, Me, 2000, XP.

Software installation

Insert the installation disk into the disk drive and start the programme set up.exe. Follow

instruction of the installation programme. You can change the suggested folder for the

programme installation and the group name of the menu for the programmes initiation.

Programme handling

All functions are activated by selecting the corresponding item of the programme main menu.

The menu functions are described in Table 1.


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Table 1.

Menu Submenu Description NotesFILE

Select a

patient

Allows to select a patient from the data archive Accessible initially

Save Retaining of performed measurement results in the data

archive

Becomes accessible, if

result of the previous

measurements is not

saved

Load Loading of measurement results saved in the archive for the

current patient

Becomes accessible

after the patient has

been chosen

Export the

conductivity

card

Allows to write numeric values of conductivity in all cross-

sections into HTML format file

Becomes accessible

after data loading from

the archive, or after

measurement

completion.

Restore now Allows to carry out image reconstruction for the current

data set, even if the image reconstruction has already been

done before

- " -

Information Makes available information about the open file name, the

patient’s code and name, his estimated age at the moment of

measurement (in years), date and time of the measurement,

comment line to the change and result of the automatic

assessment probability evidence of a malignant tumour in

the mammary gland in question.

- " -

Record Supplies the form for filling and printing of the examination

record

- " -

Printing of

images

Make it possible to select and print on one paper list (A4)

two sets of images for the current patient

- " -

Exit Programme exit Accessible initially

VIEWING

Restore the

window

extent

Restores the initial size of the window extent

- " -

Integral view Displays distribution of the measured potentials, which Becomes accessible


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corresponds to the body’s electroconductivity, integrated in

respect of depth; it makes it possible to assess the site and

the size of the zones with insufficient contacts of the

electrodes with the body.



measurement

completion.

View 1 Activates the first (main) mode of viewing - " - View 2 Activates the second (optional) viewing mode, when cross-

sectional images are represented as

“a pile of sheets”, with the possibility of selecting one of

them for detailed examination.

- " -

16 gradations The scale with 16 gradations is used for data display - " -

32 gradations The scale has 32 gradations - " - 64 gradations The scale has 64 gradations - " - To highlight

the field Makes it possible to highlight with a colour the areas with

electroconductivity within the specified range

- " -

Display parameters

Displays a window with current contrast settings and the

highlighted area

- " -

Colour scale Switching-over between grey and colour scale for electroconductivity display

Accessible initially

Display the scale

Displays the scale with gradations of colours, used for data

display

- " -

Centre of the

image

Switches on/switches off the marker of image centre

Becomes accessible



measurement

completion. Contrast setup Makes it possible to setup the grey scale to improve the

image quality Accessible initially

DEVICE Measure Start measuring (right away or, utilizing manual mode with

the help of a button on the measuring block)

- " -

Check-up Checking up of connection with the device - " - Settings Setting of the port type and number, to which the device is

connected

- " -

PATIENTS Search Specified parameters search for a patient in the current

archive with possibility of the retrieved data loading

- " -

Editing Patient information editing - " - Delete Deletion of data, concerning the specified patient, from the

- " -


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current archive

ARCHIVE Folder change Change of the current archive

- " - Select data Data selection according to various criteria with subsequent

coping into a separate archive

- " -

TOOLS Double-

window

viewing

Initiate an addition programme for data viewing, which

offers convenient viewing of two independent images from

the current archive, their statistic analysis and comparison.

See the chapter “Utilization of the double-window viewing

? Help Displays the help file - " - About the

programme Information about the programme - " -

Double-window viewing

The programme for double-window viewing is initiated with the help of the menu-item

Tools/Double-window viewing of the master programme. It provides convenient viewing of

two electrical impedance images as well as statistic analysis and comparison. For instance, it

is possible to have images of the right and the left mammary gland of the patient. The

programme provides access to two images, which can be chosen independently from the

current archive. In the window bottom part the electroconductivity frequency distribution

charts (histograms), corresponding to these images, are available. The abscissa axis in these

charts shows electroconductivity in relative units, and the ordinate axis – the number of points

with the given electroconductivity on the image.

The functions of the optional viewing programme are activated with the help of the control

item of the dialogue box and the menu-items. .

Control items

Patient №1 and Patient №2 (mixed lists) – selection of patients from the current archives;

Frame (mixed lists) – selection of changes for the specific patient;


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(buttons) – show the next measurement;

1 – 7 (switch keys) – selection of the scanning plane (depth).

Functions of the programme menu are described in the table 2.

Table 2.

Menu Submenu DescriptionFILE Brief description Displays information about the patient’s code and commentary line to the

current images.

Additional information

Displays information concerning measurements conditions, makes it possible

to introduce and display result of manual analysis of histogram and images

Printing of the left window

Makes it possible to print out the left image, the corresponding histogram,

date and time of measurements as well as commentary. Exit Exit the programme of double-window viewingVIEWING 16 gradations The 16 gradations scale is used 32 gradations The 32 gradations scale is used 64 gradations The 64 gradations scale is used

Colour scale Switching-over between grey and colour scales

Display the scale Displays the window with gradations of colours, used for data display

Contrast Makes it possible to setup the grey scale to improve the image quality

COMPARISON Left –Right Compare the left and the right images Left – NORM Compare the left image with the “normal” one. A dialogue box is display, in

which it is possible to choose data selection criteria for establishing the

“norm”.

Right - NORM Compare the right image with the “normal” one. Type of

comparison #1 Selection of the first comparison algorithm (without histogram smoothing)

Type of comparison #2

Selection of the second comparison algorithm (with histogram smoothing)

HELP Help Displays the help file

Brief help Displays the window with information concerning manipulations with


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selected image fields.

About the programme

Information about the programme

Commentaries to comparison operations

This part of the programme is intended mainly for research purposes. It makes it possible to

carry out qualitative (visual) as well as quantitative comparisons of the histograms of

electrical impedance images. The user can compare one image with another, selected at

random from the data base. It can be images of the left and right mammary glands of the same

patient. Histograms of images can be compared with so called “norm histogram”, obtained via

averaging of histograms for healthy mammary glands, received during previous examination.

The accumulated experience in visual assessment of histograms (symmetry, breadth, number

of peaks, etc.) can help to formulate the empirical selection criterion for questionable case, but

it requires rather extensive clinical practice. The normalized quantitative difference of

histograms is displayed as “coefficient” in the panel “Comparison”. This value is evaluated on

the basis of the nonparametric statistical algorithm of Kolmogorov-Smirnov and can possess

the value with the range of 0 – 1. The images difference with the coefficient exceeding 0.4 is

conceded to be rather large. For instance, if the coefficient between the current image and the

“norm” exceeds 0.4, this image should be considered as abnormal, and certain spots on such

an image might correspond to malignant tumours.

Additional options

A double click of the left mouse button on the histogram, will display information about its

parameters – mean value, minimum, maximum and mean square deviation. .

Estimation of parameters and comparison of histograms can be performed not only for the

entire image, but for its rectangular fragments – regions. In order to select the region it is

necessary:

- position the mouse curser on the image into one of the corners of the selected region;

- press the left mouse button and, without releasing it, move the cursor along the diagonal line

of the selected region;


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- release the mouse button.

When the region rectangle can be observed on the image, it is possible to click the mouse on it

in order to move the panel with the region histogram and its parameters to the upper level.


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The Translation of the Figures. Figure 4 Интегральный вид – Integral view Figure 5 Файл – File Просмотр - Viewing Измерения – Measurement Параметры – Parameters Архив - Archive Инструменты – Tools Код пациентки – Patient’s code Комментарий: левая лёжа – Commentaries: Left gland, lying supine Figure 6 Глубина – Depth Figure 7 Файл – File Просмотр - Viewing Измерения – Measurement Параметры – Parameters Архив - Archive Инструменты – Tools Figure 8 Файл – File Просмотр - Viewing Измерения – Measurement Параметры – Parameters Архив - Archive Инструменты – Tools Figure 9 Мин: - Min: Макс: - Max: Нижнее значение – Low value Верхнее значение – Upper value Установить – Set Отказ - Rejection


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Figure 10 Область - Field Файл – File Просмотр - Viewing Измерения – Measurement Параметры – Parameters Архив - Archive Инструменты – Tools Figure 11 Выбор пациента – Patient selection Пациент – Patient Код – Code Новый – New Отказ – Rejection Figure 12 Загрузка данных из архива – Archive data loading Код пациента – Patient code Кадр - Frame Отказ – Rejection Figure 13 Информация – Information Имя файла - Filename Код пациента – Patient code Имя пациента- Patient name Дата и время измерения – Measurement date and time Комментарий – Commentaries левая лёжа постменопауза 5л - Left gland, lying supine, postmenopause 5 years Рассчитанный возраст – Evaluated age Вероятность - Probability Отказ – Rejection

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ELECTRICAL IMPEDANCE COMPUTER MAMMOGRAPHonkocet.eu/download/MEIK user guide.pdf · The electrical impedance computer mammograph “МEIK”, which operation is based on the method