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					                                                  PROCEEDINGS OF SPIE



Smart Imagers and
Their Application
Victor A. Shilin
Alexander L. Stempkovsky
Chairs/Editors


6-8 October 2004
Moscow, Russia


Organized by
Institute of Design Problems in Microelectronics of Russian Academy of Sciences (Russia)

Sponsored by
SPIE Russia Chapter
Russian Academy of Sciences (Russia)
Moscow State University of Railway Engineering (Russia)
Moscow Committeee on Sciences and Technologies (Russia)
Russian Scientific Society of TOPEK—Solid State Optoelectronics Systems (Russia)
Pulsar State Research and Development Corporation (Russia)




                         Dedicated to the Memory of Professor Victor A. Shilin


                                                                                             Volume 5944
                                                                                           The International
                                                                                           Society for Optical
                                                                                           Engineering



              SPIE is an international technical society dedicated to advancing engineering and scientific
               applications of optical, photonic, imaging, electronic, and optoelectronic technoiogies.
   Research of processes of reception and analysis of dynamic digital
  medical images in hardware -software complexes used for diagnostics
               and treatment of cardiovascular diseases
                                  Y. V. Karmazikov, E. M. Fainberg
      The Russian Research Institute "Kurchatovski Institute", Institute of high technologies and
      experimental mechanical engineering (1HTEM) 1, Kurchatov Sq., 123182, Moscow, Russia

                                                           ABSTRACT

Work with DICOM compatible equipment integrated into hardware and software systems for medical purposes has been
considered. Structures of process of reception and transformation of the data are resulted by the example of digital
rentgenography and angiography systems, included in hardware-software complex DIMOL-IK. Algorithms of reception
and the analysis of the data are offered. Questions of the further processing and storage of the received data are
considered.
 Keywords: processing, storage, images. DICOM. DIMOL

                                                      1.INTRODUCTION
 Computer development and perfection has allowed it to penetrate into many fields of man's activity, including such
 conservative area as medicine. Historically the first ones used for problems of diagnostics were the static images (for
 example, x-ray pictures). Radiography transition from a film to digital ways of data storage gave opportunity to use
 additional means of image processing and analysis. Later, during development of medical devices, the opportunity for
 dynamic images using has appeared. Here are some examples of them: catheterization carried out under the
 angiographical apparatus control: diagnostic coronarography. Video series using is more and more widely applied for
 diagnostics and treatment. And nowadays in the certain areas of medical diagnostic activity work of the doctor without
 use of dynamic images is jus! impossible.

 From the first attempts ofa computerization and automation of work of the doctor there was a question of storing and
 exchanging received data. At the llrst stages informal ion interchange was demanded basically within local treatment and
 diagnostic problems (for example: maintaining archive of studies, transmitting results of studies to experts in other
 hospitals). The set of the various standards meet these local requirements was developed for maintenance of
 compatibility.

 While level o f a computerization and the penetration of computer facilities into medical technological process grow, an
 opportunity of integration of separate devices has increased a lso. The significant part of the modern diagnostic
 equipment provides the standardized interface with external information systems. The volume of the transmitted and
 stored information has increased also: from direct values of the measured sizes up to resutts of full studies together with
 the doctor's conclusion. Due to use of open standards (in most cases - DICOM 3) the modern complex medical
 equipment can work within infnisiructure of the hardware-software complexes intended for automation of work of the
 medical personnel. The medicul device grows from only a source of the information up to a full data processing and
 analysis unit with an opportunity of a bi-directional exchange with workstations and other making elements of a
 complex.

                                      2. BRIEF DESCRIPTION OF DICOM STANDARD
 DICOM is intended for transfer of medical images and the information associated with them. Such data has complex
 structure and significant volume. Now the most effective method of working with the similar information recognizes the
 object-oriented approach (splitting data into a set of objects and links between them).




Smart Imagers and Their Application, edited by Victor A. Shilrn,
Alexander L. Stempkovsky, Proc. of SPIE Vol. 5944 (SPIE. Bellingham, WA, 2005)
K77-786X/O5/S15 ■ doi: 10.1117/12.637824
                                                                                                                         83
     Standard DICOM was initially build in terms of the object-oriented approach and operates with concepts of "entity" and
     "relationship". The "entity" represents model of some object about which it is desirable to store the information - the
     patient, the image, the message, etc.. which participates in medical technological processes, for example, in radiography
     and angiography. Relationship shows attitudes of objects among themselves. Representation of results of research as sei
     of the elements described above refers to as the diagram "entity-relationship" or E-R) and represents reflection of a
     fragment of a subject domain of medical technological process. The Fig. 1 sets an example E-R diagrams for radiological
     study in terms of DICOM standard1. Descriptions of characteristics of each of entity call attributes. For simplification of
     the diagram attributes on Fig. I are not shown, but DICOM includes tabies that define their sets for each standard
     essence. For example, the entity "patient" on Fig.l has attributes, among which are "name of the patient" and " identifier
     of the patient". Shown in model on Fig. 1 entities are abstraction as do not bear the information on concrete real subjects,
     If entities attributes contain real values it changes its status from simple description up to "sample" (object bearing the
     information). According to standard DICOM work with objects is conducted being based on their models - so-called
     "Information objects", both models and tables of attributes that define them - information object definition (IOD).




                                                       Fig. 1 X-Ray study model
     The advantage of such diagrams is that they clearly show as elements of the data required in the given modelled work
     context, as the way these elements cooperate and correspond among themselves (attitudes and hierarchy of information
     elements).

     By consideration of teamwork of set of devices within structure of a information complex it is necessary to know a
     context of the transmitted information. In the point-to-point environment the user can precisely know what devices are



84     Proc.ofSPIEVol.5944
connected, what are their opportunities and, if necessary, can adjust their characteristics. For an information complex the
situation can vastly different: a lot of devices can be connected among network, and some of them can be reconilgured
dynamically to provide various variants of data sets processing or perform different operations. It means, that it is not
always possible lo know beforehand, what devices can communicate, and, hence, they should coordinate the
communication parameters for creating correct communication link necessary for performance of a user requested task.

DICOM defines functions such as "store the image " or "receive patient information" (further we'll call them "services").
These services arc realized with use of the construction known as "operation" or "notice". DICOM defines a set of
universal operations and notices and names them "DICOM-etements of service of messages" (D1MSE). The combination
of information object and such services refers to as pair service-object, or SOP. The set of base standard operations
(DIMSE) is peculiar to any SOP pair. For the deeper understanding Fig.2 shows analogy between sentence construction
in oral speech and maps it to DICOM elements'.




Class SOP represents the elementary module of the functionalities determined by the standard. Having defined class SOP
to which there should realization correspond, and a role that the corresponding device should support, we clearly
determine an exact subset of DiCOM functionalities, including types of messages used for an exchange; the data
transmitted in these messages; a semantic context in which these data should be interpreted. For concrete SOP class
device can carry out one of two roles: as "service class provider" (SCP) the device provides services of class SOP; as
"service class user" (SCU) - uses corresponding services. Besides for each combination of SOP class and a role, the
standard defines the basic set of default reactions managing communication, for example, whether the device can
initialize communication session, etc.




                                                                                                 Proc. otSPIE Vol. 5944   85
     We shall consider the basic base concepts of DICOM standard more evidently (see Fig.2). The noun "CT Image" defines
     a subject on which action will be directed; it corresponds to definition of DICOM information object. The offer created:"
     Store the Image " corresponds to a DICOM class of pairs "service-object" (Service Object Pair Class), and if the certain
     image is specified. - to a sample pair "service-object".

     Objective orientation of the standard allows carrying out decomposition of structurally complex medical information
     with the greatest possible convenience at the set requirements, keeping high flexibility in work and data controllability.

     Unfortunately, the saturation of the standard and its flexibility, on the one hand, allows to cover a large set of the medical
     equipment, and with another - leads to some divergences and, sometimes, to impossibility of full integration of the
     equipment of different manufacturers in a uniform complex. One more appreciable lack of the standard should be named
     his insistence to computing resources and throughput of network means. This feature naturally results from necessity to
     process and decode accompanied in great volume of the additional information directly medical data.




                                             Fig.3 Hardware-software complex DIMOL-IK




     The software intended for work with DICOM as experience has shown is also necessary to develop with use of the object-
     oriented approach, and at a design stage it is necessary to take into account the structures and rules of interaction offered by
     the standard, it allows to speed up development process, to avoid excessive code writing and better structure the
     software. As an initial starting example has been used software created by Mallinckrodt CTN with open source code. In
     given software changes have been brought with the purpose of increase of productivity and an opportunity of
     integration of program modules in structure is hardware - program complex DIMOL-IK.




86     Proc. Of SPIE Vol. 5944
                                        3. DICOM IN DIMOL-IK COMPLEX
Hardware-software complex DIMOL-IK (Fig.3) was created by RRC "Kurchatov Institute" and represents medical
information system for automation of work of the medical personnel in cardiological clinics. The complex essentially
changes work technology of the doctor, without reducing quality of service, allows to minimize number of routine
operations and to increase clinic throughput.

The complex provides doctors with fast access to diagnostics results, including results of radiological studies
(angiography, x-ray), conducting the electronic case record, automation of purposes and control of their performance.

Complex DIMOL-iK provides reception of the information as from the devices that do not have DICOM interface as
from the various medical devices equipped with it (digital angio unit, tomograph, the x-ray unit, etc.).




                                             Fig.4 Digital X-Ray system
In present clause work of a complex with the equipment supporting standard DICOM is considered only. As the hard
work with diagnostic images in this format demands, as was already mentioned, appreciable computing expenses and the
high network throughput, and, hence, could lead to excessive loading of the equipment of a complex, more expedient had
been recognized the decision on converting the data received from the equipment in more resource cheaper formats.


                                        4. DIGITAL X-RAY SYSTEM
The digital x-ray device working in structure of complex DIMOL-IK, provides doctors with x-ray images. Automated
workplace "Rentgen" in common working with it carries out support of documenting functions and the description of the

                                                                                            Proc. ofSPIEVol. 5944   87
study results with using normative base of a complex. Ail workstations of the complex have access to expert-radioiogists
descriptions, conclusions and also corresponding x-ray pictures executed on automated workplace "Rentgen".

Disassembly of the accepted image is made on corresponding workstation, attached to the device. Despite of increased
requirements to computing power and throughput of a disk subsystem, such decision it is more effective, as allows more
regular load balancing on hardware of a complex.

On Fig 5 the primary screen form of workplace "Rentgen" providing the basic functionality of a doctors workplace,
including work with the x-ray device is presented.

Conversion process for the x-ray pictures received from the DICOM-compatible x-ray device is presented on Fig. 6.




                                                Fig.5 Workstation Rentgen

After conversion the study images are sent on permanent storage on a server, whence they can be seen via program shell
from any workstation of a complex. For storage and work with x-ray images format jpeg had been selected with 93-97 %
quality parameter. And due to the chosen format, for viewing the image powerful hardware maintenance is not required.

Receiving process can be broken into stages:
            • reception of the image from the device;
            • converting of the staff of research in not compressed images in a format bmp;
            • compression of images injpg;
            • sending on a server (archive);




88 Proc. of SPIEVol. 5944
Data transmission occurs atop of standard network protocols, (in this case - TCP/IP). Convening (disassembly and
allocation of a graphic component) occurs on workstation, result of this stage is a bmp file. The following stage of
processing is compression of the received image in jpg.




                                                 Workstation Rentgen




                Fig.6 Receive and preprocessing algorithm For medical DICOM images. Workstation "Rentgen"


Questions of the further processing and storage of the received data (data compression degree, estimated image number,
recommended archive capacity) have been analyzed.

All received results have been realized in working now in Center of Interventional Cardioangiology in
Moscow subsystem "Rentgen", the number of patients surveyed on it is about 10-20 patients per day.

                                        5. DIGITAL ANGIOGRAPHY SYSTEM

Angiography procedures are one of the most perspective techniques of diagnostics and treatment of cardiovascular
diseases. During operation the surgeon uses angiography device as the visual control tool and records with its help
angioscenes. After the operation completes angioscenes are sent in global archive of complex, whence become accessible
to viewing on all workstations.

Now we shall consider how DICOM-compatible angiography device works in structure of hardware-software complex
DIMOL-IK {see Fig. 7).




                                                                                                 Prac. of SPIE Vol. 5944   89
                                                                         Angiography device
                                            Fig.7 Digital angiography system


For storing angiography studies the avi format with compression has been chosen. Codec we selected provides
comprehensible quality of the compressed image and enters into standard delivery of OS of family Windows, It is
obviously important that we use one of standard codecs as it allows to watch medical data on a computer in any clinic
without additional software installation.

Disassembly of the image accepted is made on corresponding workstation, working with the given device, in current
case - workstation "Angiography". Despite of increased requirements to hardware maintenance of workstation, such
decision has been recognized as more effective as allows to remove loading from the central servers and to reduce
volume of the information transmitted via network.

One of screen forms of automated workplace "Angiography" - the electronic operational journal, is shown on fig. 8. The
list of accepted with the device angioscenes, buttons for management of process of angioscenes reception from device, a
place angiography device parameters input, names of research or intervention are seen. In the area of preliminary
viewing one scene can be seen.

Process of reception and disassembly (see. Fig. 9) can be broken into some stages:
             • angioscenes reception from the device:
             • serial angioscenes converting from DICOM in sets of not compressed images in a bmp format;
             • assembly of the received sets of the images in scenes;
             • compression of the received scenes by means of the corresponding codec;
             • sending to server (in archive);


90 Proc. of SPIE Vol. 5944
In figure the processes which are carried out directly on workstation "Angiography" are separately allocated.




                                 Fig.8 Workstation "Angiography". Digital operational journal

After the transformations angioscenes are sent on permanent storage to archive of the complex, whence they can be seen
from any workstation included in his structure. And, as it has been marked above, in case of compression by the standard
codec angioscenes viewing does not need installation of the special software.

For increase of productivity of work of workstation "Angiography" and maximal use of its computing resources, we
attempt to process received angioscenes in parallel. Workstation "Angiography" works under OS Windows 2000 and
transformations in this case went in parallel threads. However because of high requirements of each proc ess to
throughput of a disk subsystem there was a concurrence between threads for a hard disk access. A result was total
productivity sharp falling during disassembly of a angioscenes package. Now workstation "Angiography" makes
disassembly of scenes strictly consistently. It has allowed to avoid a concurrence between processes and to raise speed
and comfort of work of doctors.

Questions of the further processing and storage of the received data (data compression degree, estimated image number,
recommended archive capacity) have been analyzed.

All received results have been realized in working now in Center of Interventional Cardioangiology in
Moscow subsystem "Angiography", the number of patients surveyed on it is about 7-9 patients per day.


                                                                                                Proc. of SPIEVol. 5944   91
                 Fig.9 Receive and preprocessing algorithm for medical DICOM angioscenes. Workstation "Angiography"


                                                             5. CONCLUSION
     The automated digital X-Ray and angiography systems capable to provide reception and processing of the graphic
     information of medical purpose - x-ray images and angiography films are developed. Systems support the DICOM 3
     equipment.

     It is shown that due to a used method of image and scenes converting in resource cheaper formats up to 10 times the
     required capacity of disk space for each system is reduced and a network infrastructure of a hardware-software complex
     loading can be lower.

     The used interface modules and conversion modules provide fast disassembly of the data received from the device and
     their preparation for storage in archives of the complex.

                                                              REFERENCES

     I. Steven С Horiil, Fred W. Prior, W. Dean Bidgood, Jr., Charles Parisot, Geert Claeys DICOM: An Introduction to the
     Standard. [Online.] http; //www.xray.hmc.psu.edu/dicom/dicom.intro/DICOMintro.html




92    Proc. of SPIE Vol. 5944

				
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