International Journal of Cardiac Imaging14 (Suppl. 1): 19–22, 1998.© 1998Kluwer Academic Publishers. Printed in the Netherlands.

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Filmless cardiac imaging: Motion or commotion?

Guy D. VastenaekenAgfa Medical Division, Application Department, Agfa-Gevaert N.V., Septestraat 27, 2640 Mortsel, Belgium

Key words:cardiology imaging, filmless imaging, X-Ray cine film

Abstract

At present times the medical cardiology imaging is still arguing about the usefulness of X-Ray Cine film incomparison with digital and filmless imaging. It is clear that both techniques have their advantages. X-Ray Cinefilm is a well established technique of which the possibilities are well known. At a first glance filmless imagingoffers nothing but advantages. However the whole picture becomes clear when trying to implement these systemsin a clinical environment, because at that time aspects of investments, technological continuity and risks, neededskills and effects on the workflow appear. This article has the purpose to clarify some of these aspects and giveguidance in the difficult process of making the right decision.

Introduction

More then a decade ago digital imaging was intro-duced in the cath-lab environment. From the verybeginning the pioneers claimed the enormous advan-tage of it and when the commercial systems appearedit was thought that the digital systems would quicklyreplace the actual film-based imaging, a little bit inanalogy with the CD-record which replaced the vinylrecord.

This turned out not to be true: digital imaging wasintroduced and recognized as a helpful means for itseasiness of use in the cath-lab, but the X-Ray Cinefilm was not therefore replaced as such. So, what arethe reasons why the change has not been as radicalas in the audio world ? And are we now getting ina phase where digital systems will eradicate the film-based imaging ? Looking back to what happened thelast ten years we can see and understand that there aremany elements which explain the evolution. The film-based imaging is known for its proven outstandingimage quality, widespread use and therefore excel-lence in communicating the images. This technologyis also unique and stable which is an important issue inthe cardiac environment. There is no huge investmentneeded with a huge risk of obsolescence in the comingyears nor are there disturbances in the workflow fromthe cath-lab onwards.

Going digital was perceived as an imaging solutionwith many advantages over the known use of X-RayCine film imaging. However, as one knows, with newtechnologies new and unforeseen problems occur. Onone hand it is accepted that digital systems provide fastaccess to images in the cath-lab and that there are sev-eral interesting and helpful features such as contrastenhancements, zooming, road-mapping, loops, quasion-line quantification. On the other hand there wereunforeseen or underestimated aspects related to com-munication. Much work has been done, with the CD-Ras example, based on the achievements with DICOM.To date, no unique solution is proposed for archiving,and with it the discussion of which means is the best isstill not over. Technology is indeed evolving fast andtherefore the risks of investing in a certain technologyare higher than one would think at first glance. On topof the film-based imaging there are many other digitaldata that emerged, with the high volume ultrasoundimages as one example. For the cardiologist it looksnormal to have these digital data integrated in one pa-tient file and to have them accessible at the place hewants them to be. Again this is not as easy as it looksand still much has to be done to get to a workable andstable solution. Putting it all together, the challengestill is to get to a complete integration of cardiac data.

In the mean time however, a good understandingof the possibilities, limits and risks involved in the

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process of filmless digitization is necessary. This wayit will avoid pitfalls and let the evolution be smooth,without loss of resources or quality in patient care.

Is digital cardiac imaging mature yet?

This question is not so obvious to answer as it looksat first sight. There are different aspects and functionsin cardiac imaging: the use and maturity of the digitaltechnology in each of these aspects or function maydiffer.

The first aspect is the one dealing with imagesproduced during the catheterization procedure itself.There are many vendors operating in this field, eachof them proposing their solution. At this time, themain system is still relying on captivation with a videocamera of the images produced by an analog device:the image intensifier. Digitization may be integratedby the vendor, thus giving all of the advantages whichare common knowledge nowadays. Instant replay andvarious enhancements of the images with smooth inte-gration of the system operation are some of the majorelements that characterize these systems. There arealso add-ons which may either use a separate videocamera or the analog signal of the existing camera, oreven use the digital data of the main system. Thesesystems usually perform quite well and have inter-esting price/performance/ease of operation relation.They can add some ‘openness’ to the, by nature, moreclosed systems of the main vendor.

Although the operational features and quality ofthe images for the use in the cath-lab may signifi-cantly differ, they are generally accepted as positive,independent of the system and the technology used toobtain the results.

Clearly this means that the technology is in amature phase and that basic experimentation is over.

The second aspect to consider is the non-real timeuse of the digital images, which means all what hap-pens with the images after the cath-lab procedure isfinished. Diagnostic evaluation is also generally ac-cepted and possible with the digital images. Howeverthere is an adaptation needed in the viewing and eval-uation process of the cardiologist because there is atrade between contrast and sharpness. Defining whichquality is best is not easy because the X-Ray Cinefilm gives stable and invariable high definition images,whereas in the digitized image there are digitizationeffects and lower resolution, but higher local contrastscan be achieved. This can be done by altering the

background densities which in turn means variabilityin the densities. For visual quantification purposes itmay ask supplementary interpretation efforts. So theconclusion is not that unique: depending on which as-pects are important for the cardiologist who interpretsthe images, digital may be better, equal or less in im-age quality than the X-Ray Cine film images. At thistime there are no drastic technological changes in sightwhich may alter the situation. Therefore digital solu-tions for the interpretation are mature because of therelative stability in performance, but at the same timeimmature because whenever new technology breaksthrough with more advantages, it will automaticallysupersede what exists now.

Another aspect in the use of digital techniques inthe imaging process is communication. Here the pic-ture is even less clear. At first glance and thanks to theefforts made in standardization, the CD-R seems to of-fer a mature solution. However the CD-R technologymay well become obsolete before it is widely spreadout and used. CD-R indeed had to struggle with thelimited capacity of about 700 Mbytes and slow trans-fer rates of originally 150 Kbytes per second. Differentsolutions have been implemented for the transfer rateproblem, even a specific ‘standard’ has been createdwith the CD-M to overcome the problem somewhat.By now, with the speed of the CD’s boosted to 32times the original speed, this problem is solved bythese fast CD readers. CD-M technology is not needednor useful for this purpose anymore. For the limitedcapacity the problem had to be solved by a work-around: the compression. Discussions about losslessand lossy, and how far lossy compression can go arenot over yet. During that time we have seen appear theDVD with a much higher capacity of up to 17 Gbytes.This will make the compression issue less importantfor the communication through these laser discs, butwhat is more important is that the installed base ofCD-R’s will probably only remain readable during thefirst generations of DVD readers. These elements aretypical for a non mature technology: any heavy invest-ments made are at higher risk with a high probabilityof limited lifetime.

Communication is also possible through network-ing: here however the bottleneck really lies in the hugeamounts of data to transmit. Compression may help,but the demands are so high that the steady evolutionin networking technology will immediately be used.Again it means that the technology is not mature here.

For archiving of the images the same reasoning ap-plies: mainly the huge amount of data to store leads to

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use the latest technology, which in turn means that dueto fast evolution there is no maturity yet.

Finally we can conclude that only some aspects ofthe digital imaging have reached maturity.

Digital and filmless: is it the same?

No, it is not. Digital means that some kind of digitalimaging equipment is used in the process of creatingcardiac images. This can be done in parallel with theuse of X-Ray Cine film imaging.

When there is no X-Ray Cine film used however,then the system has to be digital, but then we talk abouta filmless digital cath-lab.

Thresholds to take: the real picture

The advantages of digital imaging are often used toconvince the cardiologists to drop the use of film. Itis proposed as a swap: by eliminating the use of X-Ray Cine film costs can be reduced and this allows forthe capital investment needed for the digital systems.Again, this looks simple and straightforward, but in re-ality quite some important and difficult decisions haveto be made.

First of all for the diagnostic part; having no X-Ray Cine film means that details as perceptible on theX-Ray Cine film only, will never be seen again. Ofcourse it is a matter of choice.

For communication and more specifically forarchiving, the questions are even more drastic. De-pending on the media (CD-R, WORM, DVD, D2,SVHS, CRV,...) which can be completely digital or amix of digital and analog, the resulting quality will beequal to significantly less than the original data.

The compatibility of these media with the ones thatare used in your facility and other facilities you workwith, has to be checked and ensured to a certain extent.

Depending on the security you want concerningpossible digital data loss, you will need single or mul-tiple copies or back-ups, with all stages from no up tofully redundant circuitry.

Which medium to choose is also very difficult be-cause of the fast evolution in the digital technology.Traditionally backward compatibility is ensured foronly one or two generations, which means that inyears from now your data will not be accessible any-more, except if you make the efforts and take the costs

of upgrading and reconverting your data to the latesttechnology.

Another important question to address is theamount of data you want to have stored and how fastit has to be accessed.

The workflow also will change if you switch tofilmless operation. You will have to decide if you re-arrange your workflow or if the system has to adaptto suit your existing workflow. Future integration withother cardiac data as well as with demographic datashould be investigated, but here the picture is even lessclear which way to go. Differences in architecture canlead to incompatibilities, for which only heavy costsand time dedication can bring the solution you want.

The financial aspect finally is getting more impor-tant than originally thought. First of all there is thehigh risk capital investment and secondly you have theinteroperability with other departments. These deci-sions are not only of the resort of cardiology anymore.High tech devices and complex software to keep thewhole system running also requires dedicated, well-trained, high-level personnel. This also adds to thecosts.

The time and resources needed to investigatewhich solution is best for your needs is also an elementto consider. One easy way is to keep to one vendor, butthis is at the cost of openness towards other systemsfrom other vendors which may have better solutionsfor your specific needs.

To conclude: going filmless involves costs andrisks that are much larger than only the cost of thedigital consumable for communication and archiving.

Standards: the ultimate solution?

Yes it may be. Choosing any subsystem suiting yourneeds and plugging it in should not be a problem then.Reality is different however. With DICOM the existingstandard for communication was created. The archivalfunction is on the other hand not a part of DICOM.

DICOM is very complex and operates at many lev-els and concerns many different services. Therefore,there is no guarantee that DICOM compliant elementsplugged together will perform like you wish. Specifi-cally for networking this may be an issue: tuning theperformance is very important, and only if all the ele-ments work optimally together at all levels this can beachieved.

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Why still use X-Ray Cine film then?

Out of the reactions of many users who went filmlesswe have analyzed some trends. Users were missingthe ease of reading images when these images werenot available in the cath-lab acquisition system any-more. The X-Ray Cine film gave them fast access atthe known image quality. This quality is proven, ac-cepted and invariable in consistency. Images viewedyesterday stay the same as these of today or tomor-row, no aspect change due to image manipulation ispossible. The X-Ray Cine film also acts as a backupfor the patient, in case the digital system fails. Theproven quality and reliability of X-Ray Cine film offera security where the cardiologist can count on.

Troubles in the implementation, rework of the in-formation and workflow, discussions with the manyparties involved, wrong choices and inherent loss ofmoney, underestimation of the complexity and re-sources needed to achieve the goal were other notedreactions that led to many frustrations too.

Conclusion

The qualities of digital technology are undeniableand accepted. At the same time many questions stillremain unanswered concerning investments and tech-nological stability, especially for the cardiac images.Finally the qualities of the X-Ray Cine film for com-munication and especially for archiving are more thanever valid, in fact the quality of the X-Ray Cine filmhas continuously increased.

The costs involved with X-Ray Cine film are onlya fraction of the total investment and are worth theadditional security compared to the higher risk goingtogether with the evolution of new technologies.

There are in fact two worlds, the digital and theX-Ray Cine film with each their strong and comple-mentary qualities. Therefore using both of them iswhat looks most sensible actually, and adopting a pru-dent and conservative policy by combining the best ofboth worlds is the best way to guarantee success in themove for ever better and more efficient patient care.

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