Improved Diagnostic Processes

13.6.2.1 Description of the Different Processes

= needs same amount of

time by all types = different procedures different time needed

documentation

common pathology procedure with transportation and direct glas slide examination under microscope

final diagnosis dissection and preparation

of tissue samples

transportation of tissue sample image viewing and diagnostic

documentation

telepathology procedures with dynamic, real-time system

final diagnosis

telepathology procedures with static (store-and forward) image system

final diagnosis dissection and preparation

of tissue samples images transfered image viewing and diagnostic

on block via network

Time frame and activities of different pathological procedures:

macro

Schedule16: Time frame of different pathological procedures.

The figure above shows the processes of traditional glass slide examination (1), of static imaging telepathology (2), and of robotic real-time telepathology procedures (3). The direct comparison allows to recognize the differences between these processes more precisely and to analyze the critical areas of process efficiency. All processes are starting with the

removal of the tissue sample and end with the final diagnosis.

Lets first have a look at the common pathological procedures (1). After the tissue was removed, it has to be transported (by courier service or mail) to the pathologist. Then, at the location of the pathologist, the sample will be directly macro examined, then dissected, and then examined under the light microscope. As the illustration reflects, the time needed for the dissection and preparation of the tissue sample is the same in all procedures, just the location where it is done varies.

At the static image system, the macro examination, the preparation of the tissue sample, and the selection of the appropriate microscopical images are done at the local side. Then images are sent - all at once - to the pathological expert, who is able to examine them when it is most suitable for him. In comparison, using a real-time system, both - client and expert - have to be available at the same time, since there is an ongoing communication between both. First the expert is getting images of the whole sample for doing the macro examination. He is giving advises for the dissection. After the sample is prepared and put under the robotic microscope at the local side, images are continuously selected by the remote expert, captured by the camera mounted on the robotic microscope and transferred over the network. This process keeps on going with different tissue magnifications until an accurate final diagnosis can be made.

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13.6.2.2 Critical Aspects of Process Efficiency Conventional Telepathology

The efficiency of pathological procedures is dependent on several parameters, of which the most important is time. Time which is needed from the removal of the tissue sample until the pathological diagnosis result is available. The critical point of the traditional pathology is the distance between the place of the surgeon and the pathologist - that is the time which is needed to transport a specimen to the pathologist or the travel time of the pathologist to the place of consultation. Especially when considering intraoperative frozen section exami-nations, transportation time is a critical parameter.

Critical Factor of Telepathology Systems

With telepathology systems the time for specimen transportation is replaced by image transmission. Static systems mostly are handled synchronous. That is why the transmission speed and time of images do not matter a lot. The case examination time is distinguished into the time which the client needs for specimen preparation, image selection, and image transmission, and the time the telepathologist needs for his screen-examination. If images are not sufficient to render a diagnosis, additional images have to be selected and trans-mitted by the client and examined by the expert. This time has to be added to the total examination time.

A dynamic telepathology systems is based on an ongoing image transmission process. That is why image transmission time (speed), the amount of images per case, image viewing time, and case examination time are important parameters to measure the process perform-ance [Dunn, 1996/(1), p. 469; Dunn, 1997/(1), pp. 8-12; Dunn 1997/(2), pp. 1-10].

Regarding transmission speed, there are several variables affecting the operation time for each image: resolution, color quality, microscope magnification, quantification factor, and bandwidth of the link. Higher camera resolution results in bigger images with more pixels and longer time for image grabbing. The color quality and quantification factors affect the amount of JPEG compression. Quantification factors tune the precision of each pixel. As the quantification factor is increased, the amount of compression is increased. Increasing microscope magnification, by rotating the objective lenses, tends to decrease the complex-ity of an image grabbed from a microscope. Image complexcomplex-ity is thus inversely related to magnification for many pathology specimens [Weinstein, 1995, 222].

Viewing times are considerably longer on a video monitor than on a microscope. One fac-tor for longer viewing time appears to be system inefficiencies inherent in operating a motorized microscope by remote control. Another factor is the relatively small size of the dynamic video-imaging window, which limits the amount of information presented [Dunn 1997/(2), pp. 8, 9]. It also makes a difference whether high quality video images with high spatial resolution, color fidelity, and image stability are used, or whether lower video stan-dards such as NTSC, PAL, or RGB are employed, which demonstrate a limitation in image quality and therefore enhance the viewing time [Weinstein, 1992, p. 402]. The time for the examination of a case is also related to the experience of examining an image on the screen. Examination time will decrease with the experience gained with video image inter-pretation by the pathologists [Nordrum, 1991, p. 517; Ito, 1994, p. 805]. It is the same with certainty. At several studies, the level of certainty was higher and examination time shorter for the second group of cases. For example the time per case of 8,9 minutes decreased by 30 % for the second half of the slides at the study in Milwaukee [Dunn, 1997/(1), p. 11].

(Studies which consider the examination time needed, see appendix VI).

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13.6.2.3 Efficiency with Frozen Section Examinations

Doing frozen section examinations, turnaround time should be kept short. Turnaround time of frozen sections is the time required for the retrieval of the biopsy specimen from the operating suite until the result is available by telephone or a report is generated and sent to the client. An average for efficient frozen section examination at conventional pathology the time for transportation should not last longer than 30 to 40 minutes [Fujita, 1995, p.

105; Steffen, 1997/(2), p. 28]. This time aim can only be reached by common courier serv-ices within a distance less than approximately 30 km (with small variations due to road and geographical conditions) [Interview, Oberholzer, Basel/CH, 1999]. If these restrictions cannot be taken for granted, one of the following possibilities have to be chosen: a) do without a frozen section diagnosis, b) change the schedule of the operation in a way to coincide with the day when a pathologist is at the hospital, or request that a pathologist comes to the hospital to make the frozen section examination on the day at which the operation is scheduled, c) treatment of the patient at a hospital with a pathologist, d) expensive helicopter transportation of sample, e) or support by telepathology.

A

Figure 17: Pathological services, considered by distance.

In our example, the medical centers or pathologists’ offices A,B,C cannot be reached within this given time-frame by hospitals 1 to 6. The small hospitals 7 to 14 are able to transport their samples to a pathologist within the acceptable time frame. Hospital 13 can even choose whether to consult pathologist A or B. Hospitals 10 and 14 are at a critical edge, since the distance is around 30 km. Hospital 14 is abroad, but still served by patholo-gist B. One example is the Hospital of Lörrach/Germany, which is supported by the Uni-versity Hospital of Basel/CH.

The given example demonstrates that remote hospitals (1-6) are also able to offer surgeries with frozen section examination to their patients if telepathology support is available. In this way the overall hospital utilization rate could be increased. Hospitals which could reach a pathologist within an acceptable time have to calculate, whether it makes sense to invest in telepathology systems (e.g. if the system is also used for education or other services).

In general to complete an intraoperative frozen section examination is acceptable within approximately 10 to 20 minutes or less [Weinstein, 1992, pp. 401-402; Kayser, 1992/(2), p. 395]. If transportation time of 30 to 40 minutes is added, the tolerable examination time applying the traditional method would be 60 minutes. With telepathology, the direct exami-nation process in most cases is longer than with direct microscope examiexami-nation, but if trans-portation time is long, process efficiency is still much better than the conventional method.

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Viewing Time With Dynamic Systems

System users reported that viewing times for slides are considerably longer with a video monitor and a robotic microscope compared to conventional light microscopy. Not rarely users are unsatisfied due to the relatively slow response time of the computer-controlled, robotic-motorized microscope, and the time required to digitize, store and transmit selected higher resolution images [Dunn, 1996/(2), p. 465]. Therefore when using dynamic systems due to the number of ‘live’ images to be transferred, high transfer rate are requested. That reduces the transfer time, but by this drastically increases telecommunication costs. For a realistic calculation of transfer time, the time needed to create a connection and to com-press images has to be added to the transfer time and to the time needed for image exami-nation and documentation [Klutke, 1997, p. 71].

To examine a slide on a light microscope takes approximately 1 to 2 minutes. The exami-nation time for telepathology cases vary a lot due to the given reasons. Viewing time is dependent on transmission speed. To give an example, at a study using Intel ProShare and an ISDN line, an image of 176 x 144 pixel size, a data transfer rate of 750 KByte/min, and a compression of 1.7 approximately 10-15 video images per second could be transferred. In comparison, the transfer of an image with the size of 8,5 x 17com (1000x2000 pixel; 1.9 MByte; resolution 300 dpi) would need approximately 70 seconds [Klutke, 1997].

Considering the viewing time at a study in Milwaukee, telepathology took an average of 4.43 minutes per slide and 12.09 minutes per case [Dunn 1997/(2), p. 8]. At another study approximately 70-80 % of the diagnoses were rendered with light and video microscopy in less than 2 minutes, and over 95 % of all the cases in less than 4 minutes in both viewing modes. An interesting result of this study was that the average viewing time for false-nega-tive and false-posifalse-nega-tive decisions were nearly twice as long as for posifalse-nega-tive and true-negative decisions. This suggests that a pathologist facing an unusually long viewing time on a case may regard this as a warning sign for an increased risk of rendering an inappro-priate diagnosis [Krupinski, 1993, p. 84]. For further test results see appendix VI.

13.6.2.4 Second Opinion Examinations

If a second opinion consultation of intraoperative section cases is necessary, and since images are already available with telepathology, the pathologist can access multiple spe-cialists [Dunn, 1996/(2), p. 465]. The additional effort for such second opinion consulta-tions would just needed additional 5 to 7 minutes⁷⁷ (with ISDN 3-5 min), including image transfer, image examination and discussion of the case [Kayser, 1992/(2), p. 396]. This time has to be added to the regular examination time. Although the total examination time is increased, surgeons appreciate the possibility of fast second opinion consultations (espe-cially at frozen section examinations) and are willing to tolerate this additional time delay in circumstances to get a very reliable result [Kayser, 1993/(2), p. 397].

77 Discussion of the images, and acoustic assistance in diagnostic classification or advises lasted for average 3 minutes. Transmission time by telephone for one image was 1-2 minutes, with ISDN 10 seconds [Kayser, 1995/(3), pp. 216-217].

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13.6.2.5 Turnaround Time in Routine Cases

Employing medical diagnostic Internet services and advisors, turnaround time is often aimed to be a huge problem [Hottelet, 2000, p. 13]. Considering telepathology, at a study in USA non-deferred cases (97,5 %) executed by telepathology were examined in less than 2 days. For deferred cases 5.5 days were needed. Unfortunately, the amount of deferred cases slightly increased with telepathology.

In comparison, with conventional methods, the turnaround time of non-deferred cases was on average 4.6 days, and much longer for deferred cases [Dunn 1997/(2), p. 8]. Martin even reports about a delay in obtaining an answer with the conventional method of 8 to 15 days [Martin, 1996, p. 459].

In summary, turnaround time could have been reduced by more than 50 % with telepathol-ogy. This proves that also in routine cases the efficiency of processes with telepathology systems is much better than with conventional pathology if there is no pathologist at the place and if transportation is long.