POA_S@UDE

A New Collaborative Tele-ultrasonography System over PLC

Alécio Pedro Delazari Binotto

1,2

, Valter Roesler

, Cirano Iochpe

1,3

, André Campos da Cunha

Ronaldo Husemann

and Carlos Eduardo Pereira

1,2

Informatics Institute, UFRGS - Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, Brazil

CETA - Center of Excellence in Advanced Technologies SENAI, Av. Assis Brasil 8450, Porto Alegre, Brazil

PROCEMPA - Information Technology Company of Porto Alegre, Av.Ipiranga 1200, Porto Alegre, Brazil

Maternal-Infant Hospital Presidente Vargas, Porto Alegre, Brazil

Keywords: Telemedicine, Ultrasonography Images/Videos, Real-time Collaboration, Multimedia.

Abstract: Access to medical care is sometimes difficult to be reached by citizens living in distant and underserved

areas. The problem increases on high complexity medical cases that are not preventively identified. The

recent advance of broadband communication, like Power Line (PLC), combined with state-of-the-art

multimedia compression methods allowed reaching isolated areas that lacks of intra/internet connections.

This paper presents the results of the POA_S@UDE Project, a research that aimed the improvement of

patient quality of life in distant urban communities from high-complexity hospitals, focusing on obstetric

ultrasonography (U/S) examinations during prenatal period. Statistics show an obstetric examination miss

rate higher 60% at the Restinga peripheral district (100,000 inhabitants) in Brazil. The main reason is the

time and financial difficulties to go to central hospitals to perform regular examinations; added with the

time gap of 4 months between an exam request and its realization by the referral hospital. Based on that, we

introduce a collaborative tele-U/S system over a PLC hybrid network based on multimedia data. The

specialist doctor assists, guides, and interacts in real-time with the remote doctor who operates the U/S

equipment. At Restinga, during a pilot of 3 months, the examination waiting time was decreased to 1 month

and the miss rate of prenatal examinations to 30%.

1 INTRODUCTION

Telemedicine represents a multidisciplinary research

area. It integrates not only efforts of various fields

from Computer Science, but also different

disciplines from medicine and other health areas. In

addition, it can involve public health policies,

government strategies and public organizations. This

way, telemedicine is currently growing as a complex

research topic for the improvement of health

services, of population quality of life, and also for

remote medical training, including resident

physicians. Based on this advance, the qualified

health care of excellence medical centres is extended

to remote and underserved areas with the

indispensible government support.

Therefore, most telemedicine applications are

massively video/image-based (data from U/S, CT,

X-ray, resonance, etc.), being used not just for

teleconsultation, but also for a simple second or third

opinion, repository research or remote training

through the Internet. Those are applications that aim,

chiefly, to provide technical support on decision-

making of non-specialist doctors, who often work in

places distant from medical excellence centers.

However, this strategy depends completely on

Internet bandwidth and its reliability and data

security. Thus, due to the precarious scenario of

poor regions, the mentioned telemedicine

applications present features that originally do not

require synchronous and real-time communication

nor need to deal with large data transferences, like

video, images, textual, and voice.

Regarding U/S examinations (the focus of our

research), it must be performed by doctors

specialized at the medical discipline related to the

exam (e.g., obstetrics, fetal medicine) and

experienced with the equipment. Particularly in

Brazil, other professionals besides doctors cannot

222

Delazari Binotto A., Roesler V., Iochpe C., da Cunha A., Husemann R. and Pereira C. (2009).

POA_S@UDE - A New Collaborative Tele-ultrasonography System over PLC.

In Proceedings of the International Conference on Health Informatics, pages 222-229

DOI: 10.5220/0001541902220229

 SciTePress

operate the equipment. When the local physician

lacks the knowledge or experience at the medical

discipline to perform the exams in order to acquire

meaningful videos for interpretation, the local doctor

must take the responsibility for the final exam

diagnosis, communicating with the specialist

physician who guides all the examination and

together can generate the final diagnosis. In this

case, it is suitable that both doctors have a

synchronously data communication in real-time,

mainly at the data acquiring phase, i.e., videos

generation.

When synchronous communication of images

with good quality and real-time is required, many

factors related to network and multimedia areas must

be taken into consideration, such as bandwidth,

audio and video codification, processing capability

of the involved equipments, and the end-to-end

communication delay. Usually, these factors

determine the final video quality.

In tele-U/S, real-time applications present

specific features that demand more resources from

the computer system. In this paper, real-time means

both sides communicating and not feeling

uncomfortable with the delay. According to (Bartoli,

2007), this time should be less than 400ms in IP

videoconferences to meet ITU (International

Telecommunication Union) standards. In order to

accomplish this, our research is based on MPEG-4

video codification, offering real-time

collaborative point-to-point tools.

Regarding communication, our case study is

deployed over the power lines, designated PLC

(Power Line Communication) in Europe and BPL

(Broadband Power Line) in the United States. The

data communication through electric power nets is

already an alternative that competes and/or

complements the wireless communication systems,

satellite and wired applications, like cable TVs

(Opera, 2007). We choose that type of

communication, since it is a distinct parallel project

developed by part of the authors in the same region

of the presented case study.

Based on that, this paper presents the results of

an innovative telemedicine pilot service over PLC,

named POA_S@UDE, performed at the city of

Porto Alegre (Rio Grande do Sul State, Brazil) and

its poor and remote district called Restinga. The

paper is organized as follows. It starts in Section 2

with a brief motivation and description of the

medical scenario, followed with previous and

parallel work on projects in the telemedicine and

PLC areas in Section 3. The proposed platform is

detailed on Section 4, emphasizing U/S obstetric

examinations over a hybrid PLC network. Finally,

on Section 5, we present medical, technical, and

social results achieved during the pilot and

discussions about its benefits and future directions.

2 MOTIVATION

At Porto Alegre (1.5 million inhabitants), the

Maternal-Infantile Hospital Presidente Vargas

(HPV) is a medical referral center focusing

pregnancy. The public hospital assists a vast part of

the population who lacks of specialized maternal

infrastructure. Most of its patients come from remote

districts just for the accomplishment of routinely

U/S examinations and for accompaniment of

pregnancy evaluation.

Restinga is the poorest and most remote district

of Porto Alegre, having more than 100.000

inhabitants with a population density of 23

inhabitants/ha, occupying more than 20.000 homes.

The growth tax between 1991 and 2004 was 5.6%

per year and the average monthly income of the

answerable for the domiciles is 3.03 minimum

wages. The district counts just with a small health

center and lacks of specialist physicians and basic

medical devices, which sums up an average of 300

patient transfers to HPV per month for basic

ultrasound examinations, being more than the half in

the field of obstetric/gynaecologic. In this manner, it

overflows the HPV capacity with patients that, in the

majority of the cases, could be assisted in their own

district by available General Practitioners, the

residents, whom could be guided by an expert doctor

using a basic structure with U/S and internet

connection. In fact, most of the cities have a basic

structure of general doctors who, very often, cannot

give a final and correct diagnosis without a second

medical opinion or assistance/discussion.

According to the WHO - World Health

Organisation (WHO, 2008), women need to visit a

hospital at least 4 times during the pregnancy for

periodically accompaniment. However, at Restinga

there are cases where the patient visits the hospital

for the first time just to give birth. To better illustrate

the precarious scenario from that region, there is an

obstetric examination miss rate higher that 30% in

U/S exams for pregnant woman at Porto Alegre and

more than 60% at Restinga. In addition, Restinga

presents a time gap of more than 4 months between

an exam request, by the periphery health center

generalist physician, and its realization by the

specialist doctor of the HPV.

POA_S@UDE - A New Collaborative Tele-ultrasonography System over PLC

223

3 PREVIOUS EXPERIENCES

In the recent past and at present, some technological

projects aiming social inclusion were developed at

the Rio Grande do Sul State. Two of them,

T@lemed and PLCRestinga, are the infrastructure

basis for the presented system. The first deployed an

image-based telemedicine system over the State,

while the second integrated Restinga’s public

buildings using PLC, since there was no fast internet

connection until the year of 2006. The next sub-

sections go in detail over these projects, as well as

give an overview about other related work.

3.1 Related Work

The Brazilian Government, through the RUTE

(University Telemedicine Network) initiative -

(Rute, 2008), (Simões, 2006) - has been investing at

the development and online availability of

knowledge databases related to health. The goal is to

subsidize the decision-making of health

professionals who act far from the reference medical

centers. It is a try to improve decision quality and

reduce the "ambulance-therapy" phenomenon.

Another situation was presented by (Sibert,

2008), which performed an experiment of U/S

laryngoscopy images and video transmission in rural

emergency situations. The images were transmitted

from the ambulance through mobile phones 3G

connection, but in low quality. Results showed good

system acceptance by the doctors, but with remarks

regarding image quality.

In the work of (Yee, 2005), an experience

similar to the one presented here, two hospitals in

Australia made transmissions of the ultrasonography

device screen aiming a third medical opinion. They

tested over several network rates and came to a

conclusion about the best cost-benefit rate for a good

video quality. It was a bandwidth around 1Mbps.

The work of (Reddy et al., 2000) proposed a

solution for fetal tele-U/S in remote canadian

communities, where 49 patients were observed in

remote obstetric ultrasound examinations. The

practical environment comprised two personal

computers linked via 19.2 kbps modem over an

analog telephone line.

In addition, (Chan et al., 2000) proposed a real-

time transmission of fetal ultrasound images over

long distances via ISDN lines. A link of up to 2

Mb/s was established. The proposed system

incorporated built-in interactive two-way

microphones, allowing direct communication

between both sites. Examination video has been

captured by dedicated video boards and transmitted

in rates of 30 frames per second. Over a 3-month

pilot period, 24 tele-U/S examinations were carried

out. Overall, the consultations resulted in

modifications compared to clinical diagnosis in

45.8% of the cases and modifications to the

management plan in 33.3% of the cases.

3.2 T@lemed

Following the telemedicine concepts, the T@lemed

Project (T@lemed, 2007) was based on a

teleconsultation platform, named TeleConsult,

which was developed by MedCom GmbH and the

Fraunhofer IGD and allows store-and-forward

DICOM image-based tele-diagnosis in on-line mode

or either off-line.

The TeleConsult software platform is based on

TeleInViVo (Kontaxakis et al., 2000), which is a

telemedicine workstation used in isolated areas such

as islands, rural, and crisis situation areas. The

system integrates in one custom-made device a

portable PC with telecommunication capabilities and

a light and portable 3D ultrasound station,

combining low price, low weight, mobility and a

wide range of non-radiating examinations. The

integrated workstation used advanced techniques

able to collect 3D U/S data, which were presented

on (Sakas, 1993) and (Sakas et al., 2000).

For T@lemed and for this research, the reason to

work with ultrasound data is based on its support to

a very large range of applications (Ferrer-Roca et al.,

2001), varying from gynaecology and abdominal

scans to cardiological examinations. Currently, it is

the only economically and practically affordable

imaging modality.

Figure 1: TeleConsult collaborative annotations.

As an example of its functionalities, after the

data transferring, interaction can be made in real-

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time. Digital annotations in the medical images can

be made by the generalist and sent to the specialist

physician, aiming to delineate some region of

interest to be argued. The data sending can be

carried through an off-line connection, where

messages (images + annotations + first opinion +

other crucial region of interest) are sent in

determined moment (at night, for example) and later

on, at another moment, the specialist performs the

diagnosis or opinion; or through an on-line

connection. In this last way, depending on the

bandwidth, the data are transmitted in few seconds

and collaborative discussion (annotations + chat +

voice + measurements + interaction), is carried in

real-time. Figure 1 depicts an annotation interaction.

In the scope of T@lemed, doctors from four

remote cities of the Rio Grande do Sul State were

connected over wired internet (512Kbps) with a

referral hospital located at Porto Alegre.

3.3.1 PLC Restinga

The PLC Restinga Project, PLC network at

Restinga, arises to supply an economical gap

promoted by wire telecommunication companies to

attend deprived communities. Concerning the work

of (Borges, 2005), the digital inclusion goal in Brazil

is to look for the population (or at least its great

majority), to be able to receive access to tools,

services, and necessary technological abilities in the

new economy. The PLC technology implementation

cost and installation, using the medium tension net

for data transmission, could be cheaper than the

costs of available technologies.

Figure 2: The PLC network at a whole.

With further technological details, we can

basically classify the segments of communication

networks via PLC in 4 areas, but the following 3

were used in our work (see Figure 2):

 Medium Tension: interval between the electric

power company substation and the

transformer of low tension that serves the final

consumers;

 Last Mile: interval of electric net in between

the transformer of low tension and the

consumer's residence;

 Last Inch: interval of electric low tension net

located in the consumer's dependences.

Taking advantage of the fiber optic network from

the Information and Communication Technology

Company of Porto Alegre (Procempa), which is

interlinked to the optic ring from the State Company

of Electric Energy, a PLC network was deployed,

beginning from the substation, located in one of the

extremities of the Restinga neighborhood (point 0 in

Figure 3). In addition, four different points are

connected, chosen from its geographical position

and lack of digital services: (1) public primary

school; (2) district administrative center; (3)

professional primary school; (4) the previous cited

Resting health center.

Figure 3: PLC medium tension map at Restinga.

The pilot reaches a linear extension of

approximately 3.5 kilometers of PLC, transmitting

data in high-speed (45Mbps, since we use the first

generation of equipments) on the electric network of

energized medium tension (13.8 kV). The project

foresees several services, taking maximum

advantage of the communication speed. Thus, its

importance for telemedicine applications that needs

normally high bandwidth when dealing with

multimodal (large image/video data, voice, etc.) high

quality data.

The network implementation was only possible

due to the optic fiber channel located at the

substation (point 0), i.e., it is a hybrid network

topology and the PLC phase accomplishes the “red”

POA_S@UDE - A New Collaborative Tele-ultrasonography System over PLC

225

lines of the figure. At a glance, starting from this

point, the sign from the optic fiber is injected in the

medium tension net throughout capacitive couplers

and goes direct trough the electrical line, with

acceptable losses, in distances of up to 1200 meters,

where regenerators modems are installed aiming the

system sign losses reconstitution. Repeating

modems are also installed in these points to overlap

the maneuver keys and the derivations in the

medium tension net. In the extremities, special

modems are used and receive the PLC signal from

the medium tension and re-inject this signal in the

electric net of low tension (127V/220V). The signal

that arrives in the assisted points through the low

tension is extracted from the power plug using a

modem for low tension.

4 THE POA_S@UDE PLATFORM

Based on physician needs, the proposed system

should compromise with the following concerns:

• Good Ultrasound Video Quality: show

details in the ultrasonographies. This

demand is subjective and the adequate

quality is determined by the doctor when he

can distinguish the meaningful regions of

the fetus needed to perform the correct

diagnosis and taking responsibility for it;

• Perceptible Movements: should show

matters as mainly the fetus heartbeats and

the respiratory system. This demand is

also subjective and also determined by the

doctor;

• Audio Communication: between the

specialist doctor and the support resident

physician;

• Remote Pointer: the specialist doctor can

show details to the patient and the resident

physician (who is with the patient). It uses

its mouse inside the ultrasound area and the

mouse movements are send to the remote

place, showing specific areas which the

doctor wants more attention;

• Hand Probe Position: video showing the

hand of the remote resident physician,

which shows the transducer position on the

patient's abdomen.

Figure 4 shows a schematic of the developed

solution. At both ends, there is audio coding and

transmission. In the remote module, the system

receives the video signal from the U/S and the hand

position of the attendant, composing both videos on

the same screen. The attendant hand is in PIP

(Picture in Picture) form, generating a small

resolution video. This signal is coded in MPEG-4

and transmitted live, being received by the doctor,

who analyses it and communicates by audio and

through the remote pointer, giving instructions.

Figure 4: System Overview.

The TeleConsult was used to capture the U/S

signal that is sent through the PLC hybrid network

from the remote health center to the referral hospital.

In our case, there is a non-specialist physician (a 4th

year resident) who performs the exam. At the main

hospital (HPV), the specialist doctor is responsible

to assist, guide, and interact with the non-specialist

in order to perform the final diagnosis.

The system internal structure, placed at the

health center, is shown on Figure 5. A short

description of each module is presented bellow:

• Capture: responsible for receiving the

audio and video signals generated by

external equipment, such as camera and

microphone, independent from the

communication interface (DV, acquisition

card or USB). In the specific case of tele-

ultrasonography system, the capture

module received four simultaneous

captures: a) the U/S video signal; b) the

video signal showing the attendant’s hand

position; c) the attendant audio; d) the

video monitor image;

• Audio and Video Coding: responsible for

compressing the audio and video streams,

captured for later transmission. The generic

interface allows working with different

coding algorithms. The available video

coding algorithms are MPEG-2, MPEG-4 e

H.264 protocols, and the audio coders are

G.711 and AAC (Advanced Audio Coding)

protocols. In this case, the coding was

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compressing the audio and image from the

video monitor;

• Network: implements the point-to-point

communication between the local and the

remote locations.

• Audio and Pointer Decoder: decodes the

audio that comes from the main hospital, as

well as the pointer signal controlled by the

doctor;

• View: shows at the video monitor: a) small-

sized image of the attendant hand position;

b) large-sized ultrasound image; c) remote

pointer image, controlled by the doctor.

Besides that, it decodes the doctor's audio

and presents it on the speakers.

Figure 5: The remote health center system modules.

The system diagram placed at the referral

hospital is complementary to the previous one and

illustrated by Figure 6. The main differences are that

the system codes only audio and pointer. Besides,

decodes the remote audio and video, presenting

them on the computer screen.

Figure 6: The referral hospital system modules.

5 RESULTS

According to (LeRouge, 2002), any application

related to telemedicine with videoconference ought

to study the effectiveness of practical requirements

in order to reach the aimed system quality. To reach

the concern of quality for perceptible fetus

movements, some preliminary experiments were

performed on 2 CPUs (Dual core Pentium 3.4GHz, 2

GB RAM). The evaluated parameters were:

• Video compression using the codecs

MPEG-4 part 2, H.264 and MPEG-2;

• Resolutions of 720x480 and 320x240

pixels;

• 15, 20 and 30 frames per second;

• Bandwidth (bitrate) of 500 kbps, 1 Mbps,

1.5 Mbps and 2 Mbps;

• Audio AAC (Advanced Audio Coding) 64

kbps and 128 kbps.

The H.264 encoder produced good video quality,

but demanded high processing power from the

computers during video encoding process. Besides

that, it increased the total delay to around 1 second

and in some condition caused application freeze.

MPEG-2 and MPEG-4 encoders resulted small delay

(lower than 300 ms). MPEG-4 provided better video

quality compared to MPEG-2, being chosen.

Any resolution below 720x480 was considered

improper according to the specialist doctor, mainly

because of artifacts and pixel interpolation problems

detected in the reconstructed video, which could

invalidate a correct medical interpretation.

Some experiments changing the number of

frame per seconds were also performed in order to

define the better relation between frame rate and

visual movement video requirements. With 20

frames per second, the result was acceptable, but

was better using 30 frames per seconds. Regarding

audio, the tests showed to use the AAC codec with

128 kbps, providing a better audio quality.

The experiments were performed changing the

overall connection bitrate for audio and video, and

the system was tested with 500 kbps, 1 Mbps, 1.5

Mbps and 2 Mbps via PLC. The increasing of the

total multimedia (audio and video) bitrate produces

better quality; however, it is a limited resource. The

best cost-benefit was obtained using 1 Mbps, which

was the rate established to the system.

The mean transmission delay was measured with

the help of a clock, which was filmed while

transmitted, and the overall one-way delay was

about 300ms, meeting with communication needs

between doctors and being considered real-time

according to previous definition.

With these parameters, the case study could

accomplish the fetus movements and meet the

original need of verifying the heartbeats and

breathing movements.

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227

Regarding the pilot at the remote health center,

about 40 monthly tele-ultrasonographies were made

during a 3-month pilot and the forecast is to increase

this number to 600 monthly exams, covering other

health centers spread over Porto Alegre. Figure 7

presents the environment at the remote health center,

where the resident physician positions the U/S probe

according to the doctor's remote guidance. Besides

that, it shows the U/S equipment (white, on the

table), the video monitor attached to the acquisition

computer (behind the U/S), and the video camera

that records the transducer and hand of the local

physician (behind the patient).

Figure 7: Exam being held at the remote health center.

Figure 8 presents the referral side, showing the

specialist doctor at the HPV watching the

transmission and guiding the resident physician

through audio and using his mouse pointer. From the

figure, it is possible to note the U/S screen as well as

the small image showing the hand position of the

remote physician. The doctor has also a "remote

pointer", which uses to show regions of interest

commenting by audio.

Figure 8: Remote attendance by the specialist doctor.

During the first month of use, 40 patients were

interviewed to collect subjective opinions about their

experience. The major advantages mentioned were

related to being close to home and the decrease of

waiting time to perform the exam (from the original

4 months to actual 1 month). However, this time

should decrease, since the statistics considers a

number of exams requested before the system started

working, i.e., there is a repressed demand which is

being minimized at each new exam session at the

remote health center.

In addition, the patients reported that did not feel

the attendance was impersonal for the fact of

interacting also with a doctor located in another

place. It is also interesting to mention that the

consultations identified, up to now, four cases that

required immediate treatment and patient transfer

due to bad fetus formation, i.e., it was detected

preventively and the forwarding could be well

planned.

6 CONCLUSIONS

This paper presented a new tele-U/S system being

used not just as pilot project, but it is in continuous

use as a pilot service. It connects a poor, distant, and

very populated district with a referral hospital

located at the city via a hybrid PLC network. The

platform was developed by a multidisciplinary team

and was submitted to several technological and

medical experiments. Final results pointed to the use

of MPEG-4 video codec, AAC audio codec, and

resolution of 720x480 pixels to achieve the real-time

interaction of 30 frames per second. The obtained

delay was 300ms, which is better than the 400ms of

worst case in the standard of IP videoconferences.

The directly benefited by POA_S@UDE can

be sorted in two groups: pregnant patients residing

in the peripheral areas of Porto Alegre, i.e., Restinga

up to now; and non-specialist or resident physicians,

who act in health centers distant from the central

area. The benefit for the first group is the reduction

of the absences in prenatal exams and the

consequent early diagnosis of pregnancy problems.

The second group is benefited by the training and

constant contact with the specialist doctors from the

reference center.

It is important to mention that the number of

patients who submitted to the prenatal obstetric

exams through the new telemedicine system is still

small. However, all the patients who already made

the U/S examinations via the platform manifested

their contentment about being able to perform the

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prenatal exams close to their homes, saving transport

and being able even to take their other children to

the health center. Even more important, the spatial

distribution of the exams reduced their waiting time

(from 4 months to 1 month) and could now

accomplish with the WHO recommendation of 4

medical visits over the pregnancy time. According to

the Porto Alegre Health Ministry statistics, this will

guarantee an increase at the average

ultrasonographies per pregnancy that today, at

Restinga, is between 0 and 1, to at least 3 or 4, until

the end of 2008.

As future directions, the telemedicine service is

expected to be deployed in other neighborhoods or

regions distant from the downtown, such as the

regions of Guaíba Islands and Lomba do Pinheiro. A

"mobile unit" will be equipped with the system,

which will be connected to HPV through network

points at the health care centers of the covered

regions. The unit will be able to transport a resident

physician and a computer technician and each new

health care center is planned to be attended in one

day of the week, reducing the system costs.

ACKNOWLEDGEMENTS

We would like to thank Porto Alegre City Hall at a

glance, HPV and Restinga health center physicians,

and CEEE (State Company of Electric Energy).

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