J Telemed Telecare 2008;14:439-442
doi:10.1258/jtt.2008.080603
© 2008 Royal Society of Medicine Press
RESEARCHOriginal articles |
The effectiveness of low-cost teleconsultation for emergency head computer tomography in patients with suspected stroke
Kanitpong Phabphal * and
Siriporn Hirunpatch 
* Division of Neurology, Department of Medicine;
Division of Radio-diagnosis, Department of Radiology, Faculty of Medicine, Prince of Songkla Univiersity, Thailand
Correspondence: Dr Kanitpong Phabphal, Division of Neurology, Department of Medicine, Faculty of Medicine, Prince of Songkla Univiersity, Hat Yai, Songkhla 90112, Thailand (Fax: +66 7442 9385; Email: pkanitpo{at}medicine.psu.ac.th)
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Summary
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Teleradiology in an emergency situation can be used to support
rapid neurological decision-making when specialists are remote
from the hospital concerned. We have developed a low-cost system
using a PDA phone as the receiving equipment. The experimental
system was based on a notebook PC to send the images and a PDA
phone to receive them. We used commercially available toolbar
software for transmitting the information through the mobile
phone network. A total of 100 images from clinically suspected
strokes within the previous 24 hours were transmitted to a neurologist.
The mean size of the original picture was 20.9 kByte and the
images were compressed by approximately 2:1 before transmission.
The mean transmission time was 48 s per image. The diagnosis
from the PDA phone image was in complete agreement with the
diagnosis from the original image in cases of acute ischaemic
stroke, intracerebral haemorrhage, metastasis and in normal
scans. However, there was agreement in only 7 of the 8 cases
(88%) of subarachnoid haemorrhage. The overall transmission
cost was 400 Thai baht per case. The study showed that good
accuracy can be achieved with a low-cost system for teleradiology
consultation in stroke.
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Introduction
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Teleradiology in an emergency situation can be used to support
rapid neurological decision-making when specialists are remote
from the hospital concerned.
1 The rapid technological development
in communications has resulted in a growing number of reports
concerned with the technical performance, purchase price and
running costs of a variety of teleradiology systems.
2–4 The main differences in the technology are the way in which
the image is transferred, the hardware and software requirements,
and the speed of data transfer. In cases of stroke, time is
of the utmost importance. Immediate neurological consultation
is necessary for those patients who have acute neurological
deficit with a strong suspicion of a stroke, so that the appropriate
treatment can be administered, especially thrombolytic drugs
where indicated. Most clinical information can be given to a
neurologist by telephone, but it is better to show the patient's
head computer tomography (CT) scan directly to the neurologist
than to give only a verbal description.
In a developing country such as Thailand, the neurologist, neurosurgeon and neuroradiologist may not be available at all times or in all hospitals. Currently there are no more than 400 neurological specialists in Thailand and only one neuroradiologist in the south of Thailand. A patient who is suspected of having had a stroke needs quick decisions made by a specialist doctor. Teleradiology can improve patient care and reduce costs by avoiding unnecessary patient transfers.5 Although the technology of teleradiology is expensive and not yet generally available in Thailand there are, however, mobile telephone networks covering nearly all the country which provide wireless connections for many purposes such as image transfer, MMS or SMS.
The Personal Digital Assistant (PDA) has become a popular device in the last few years. It is not too expensive and is readily available in shops. PDAs have become an increasingly valuable tool in clinical medicine.6–8 Recently, PDAs have been incorporated into mobile phones (PDA-phone) which provide mobility and portability. Kim et al. recently described a PDA-phone-based system and indicated that it could provide an effective means for emergency teleconsultation without limiting the physicians to a fixed location.9 Reponen et al. have studied 68 cases of emergency CT consultations based on a portable PC and a GSM mobile phone system. The transmitted images were acceptable for final diagnosis in 72% of the cases.10 In a neurological emergency setting, Reponen et al. reported their initial experience of a wireless PDA based on a GSM digital mobile phone transmitting CT scans to a neuroradiologist and they found a good accuracy.11 However, to the best of our knowledge, there have been no studies made of patients suspected of or with acute stroke. We have developed a method for utilizing the mobile phone network for teleradiology consultation by neurologists anywhere outside the hospital for those patients who are suspected of having had a stroke. The present study was designed to assess the accuracy of diagnosis, cost and the transmission time to a PDA phone.
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Methods
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We included patients where there was a high suspicion of a stroke
and who had the onset of neurological deficit within 24 hours.
Patients with a high probability of having had a stroke are
those: (1) presenting with a sudden neurological deficit; (2)
who have no history of trauma; and (3) diagnosed as a stroke
by the emergency physician or resident from the internal medicine
department. An emergency head CT scan was performed in all cases.
The captured image was then converted to a Joint Photographic
Experts Group (JPEG) formatted image. JPEG is a means of compressing
the size of computer images so that less storage space is needed
on a computer and thus shorter transmission time required when
relaying the image. Lossy JPEG compression can be used in clinical
radiology.
12 We saved the image on the hard disk of a notebook
computer (Latitude D500, Dell).
We used a PDA phone as the receiving equipment (IPAQ hw6515 mobile messenger, Hewlett Packard). The image transfer system was programmed using AIS SMS/MMS toolbar software for installation in the notebook PC. The PDA phone used the Windows 2003SE operating system and HP image software to view the image.
An image was made and diagnosed by a qualified neuroradiologist from the original high resolution picture in DICOM 3 format. The monitors had 1024 x 1280 pixel resolution, LCD display type and 32-bit colour. Image selection for transmission and diagnosis was then made by a trainee resident guided by the consultant neurologist who was given the clinical details verbally. Only one image per case was selected to decrease the cost of transmission, which was 4 baht per picture (US$ 1 
33 Thai baht). The neurologist in a remote location then made a diagnosis based only on the transmitted picture received on the PDA phone. The mean size of the received images was 10.7 kByte and the image could be zoomed in and out. The diagnosis was then subsequently compared with that of the neuroradiologist from the full original high resolution format scan in DICOM3 format. The study was approved by the appropriate ethics committee.
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Results
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One hundred head CT images were selected, of which 21 were considered
normal, 46 showed acute ischaemic stroke, 14 acute intracerebral
haemorrhage, 6 metastasis, 8 subarachnoid haemorrhage and 5
subdural haematomas. The mean size of the original picture was
20.9 kByte (Table
1). The comparative diagnoses between
the original and PDA images were in complete agreement for acute
ischaemic stroke, intracerebral haemorrhage, metastasis and
normal scans. However, there was agreement in only 7 of the
8 cases (88%) of subarachnoid haemorrhage (Table
2). After
a subsequent independent review of the original image (in DICOM
3 format) the neurologist and neuroradiologist agreed over the
diagnosis of the eighth case of subarachnoid haemorrhage. Figure
1 shows a picture of acute ischaemic stroke with haemorrhage transformation.
Image (a) shows a picture (JPEG format) from the notebook PC
and image (b) shows the same picture (JPEG format) from the
PDA phone.
View this table:
[in this window]
[in a new window]
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Table 2 Pathological findings for patients who were strongly suspected of a stroke on history taking and physical examination
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View larger version (97K):
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[in a new window]
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Figure 1 CT scan showing acute ischaemic stroke with haemorrhagic transformation: a) original image on notebook PC; b) Received image on PDA phone
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The mean time from capture to transmission to the PDA phone
was less than 1 minute (48.3 s) (Table
1). The overall
cost per call was 4 baht per case.
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Discussion
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A conventional teleradiology system uses sophisticated technology
and is expensive. Reponen
et al. have reported on useful radiological
subspecialist consultations for CT images with a portable PC
via a GSM mobile phone.
10 The transmission time via GSM for
a single CT image was 1 minute. The transmitted images were
acceptable for final diagnosis in 72% of the cases. However,
this study by Reponen
et al. did not study an emergency situation
and did not focus on stroke patients.
10 In a subsequent investigation,
Reponen
et al. studied the emergency situation.
11 They used
a wireless PDA for reporting 21 emergency CT scans. The transmission
of a single image took 90 s. In 18 of the 21 cases the findings
were compatible with the reference film and three cases had
minor differences of no clinical importance.
We have developed a method which reduces the cost of image transfer. Although teleradiology in teleconsultation in cases of strokes requires a sufficiently accurate diagnosis for a successful outcome, the transmission time and cost are also important. We captured the image in JPEG format to reduce the image size but still maintain a high image quality.
Our study showed that high accuracy of diagnosis and short transmission time are achievable at very low cost. The accuracy of diagnosis in our study was nearly 100%, with 1 in 100 cases being misdiagnosed on the PDA phone. This misdiagnosis probably resulted from the selection of the slice transmitted to the PDA. This particular patient with the incorrect diagnosis had intraparenchymal haemorrhage and secondary subarachnoid haemorrhage, but the selected image showed only intraventricular haemorrhage.
The limitations of our study were, first only a small number of images showed subtle lesions whereas the majority showed obvious lesions. The subtlety of the lesions were hyperacute or acute infarction, which in our study were: (1) three cases of the attenuation of the lentiform nucleus and parenchymal hypodensity; (2) two cases of decreased corticomedullary differentiation; and (3) one case of loss of insular ribbon. The telediagnosis in each of these six lesions was in agreement with the diagnosis from the original image. Second, the study had only two independent observers who made the diagnoses. Third, the transmission rate and size using the AIS SMS/MMS toolbar software was limited to no more than a 90 kByte image size.
Using a PDA phone for teleradiology and teleconsultation is convenient, highly portable and relatively inexpensive. It does not require specialist radiologist hardware and associated software for teleconsultation involving CT scans. Due to the limited number of specialist neurologists in Thailand, it is impossible for them to be available at all times in the hospitals. Thus a low-cost teleconsultation method is both helpful and decreases the work load by reducing the number of separate hospital visits required specifically to view images. A major benefit of the technique is the immediate communication with a specialist for an emergency decision. We believe this will be of enormous benefit in the emergency room, when evaluating subtle lesions in acute ischaemic stroke.
Accepted September 29, 2008
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References
|
|---|
- Yamada M, Watarai H, Andou T, Sakai N. Emergency image transfer system through a mobile telephone in Japan: technical note. Neurosurgery 2003;52:986–8[Medline]
- Goldberg MA, Rosenthal DI, Chew FS, Blickman JG, Miller SW, Mueller PR. New high-resolution teleradiology system: prospective study of diagnostic accuracy in 685 transmitted clinical cases. Radiology 1993;186:429–34[Abstract/Free Full Text]
- Yamamoto LG, DiMauro R, Long DC. Personal computer teleradiology: comparing image quality of lateral cervical spine radiographs with conventional teleradiology. Am J Emerg Med 1993;11:384–9[Medline]
- Dwyer SJ, Templeton AW, Batnitzky S. Teleradiology: costs of hardware and communications. Am J Roentgenol 1991;156:1279–82[Free Full Text]
- Stoeger A, Strohmayr W, Giacomuzzi SM, Dessl A, Buchberger W, Jaschke W. A cost analysis of an emergency computerized tomography teleradiology system. J Telemed Telecare 1997;3:35–9[Abstract/Free Full Text]
- Busch JM, Barbaras L, Wei J, Nishino M, Yam CS, Hatabu H. A mobile solution: PDA-based platform for radiology information management. AJR 2004;183:237–42[Abstract/Free Full Text]
- Documet J, Liu BJ, Documet L, Huang HK. Wireless remote control of clinical image workflow: using a PDA for off-site distribution and disaster recovery. J Am Coll Radiol 2006;3:520–7
- Yaghmai V, Kuppuswami S, Berlin JW, Salehi SA. Evaluation of personal digital assistants as an interpretation medium for computed tomography of patients with intracranial injury. Emerg Radiol 2003;10:87–9[Medline]
- Kim DK, Yoo SK, Park JJ, Kim SH. PDA-phone-based instant transmission of radiological images over a CDMA network by combining the PACS screen with a Bluetooth-interfaced local wireless link. J Digit Imaging 2007;20:131–9[Medline]
- Reponen J, Ilkko E, Jyrkinen L, et al. Digital wireless radiology consultations with a portable computer. J Telemed Telecare 1998;4:201–5[Abstract/Free Full Text]
- Reponen J, Ilkko E, Jyrkinen L, et al. Initial experience with a wireless personal digital assistant as a teleradiology terminal for reporting emergency computerized tomography scans. J Telemed Telecare 2000;6:45–9[Abstract/Free Full Text]
- Kalyanpur A, Neklesa VP, Taylor CR, Daftary AR, Brink JA. Evaluation of JPEG and wavelet compression of body CT images for direct digital teleradiologic transmission. Radiology 2000;217:772–9[Abstract/Free Full Text]
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Summary
Introduction
