A Lossless Compression

Published Date
01 - Aug - 2005
| Last Updated
01 - Aug - 2005
A Lossless Compression
Ever wondered how hundreds of echocardiograms get stored in a hospital? Actually… how many of us even know what an echocardiogram is? Simply put, an echocardiogram is a study of the heart using high-frequency sound waves.

The objective of an echocardiogram is to visualise the heart chambers, thickness of the muscle wall, heart valves and major blood vessels located near the heart. A non-invasive procedure, there is no cutting and sewing involved. The picture obtained is more detailed than an X-Ray image. This test is used in the diagnosis of a number of heart conditions.

Now that you are familiar with an echocardiogram, let us understand the importance of  image and data compression technology to store multiple echocardiogram records without any quality loss.

Archiving, A Necessity
A lot of hospitals and clinics around the world keep an archive of these records in an analogue format, such as cassette tapes. In the West, the law makes it necessary for clinics and hospitals to maintain these records for a period of at least seven years, whereas India has no such law pertaining to medical records.

In the event of such legislation here too, hospitals will have to invest lots of money into setting up and maintaining databases, analogue or otherwise. Now, any analogue storage system can deteriorate under humid conditions. Also, maintenance of these tapes needs considerable time and money. If the hospital has a large number of records then indexing, labelling and retrieval of data would need a separate department. What do you do in such a situation-computerise?

However, if the data to be stored is huge, you would also need to compress it. As such, compression involves some loss of quality, the loss being directly proportional to the compression ratio. This is where the new technology comes into play. Called 'EchoView Convert', this compression technique was developed by the Singapore-based MatrixView Technologies who also have a research centre in Chennai.

The compression ratio is so high that even after a high inflow of patients, storing all their echos and ultrasound scans is not a problem"
Praveen Vemula, Technical Officer,  Hospital Administration, Sri Sathya Sai Institute of Higher Medical Sciences

MatrixView claims its compression technique as the "world's first completely digital echocardiogram storage and retrieval system at mathematically lossless quality and high compression ratios."

A Step Towards The Future
Sri Sathya Sai Institute of Higher Medical Sciences at Whitefield, on the outskirts of Bangalore, is one of MatrixView's clients in India. The institute is a hospital set up by the Sathya Sai Trust. Though the hospital renders its services for free, it has state-of-the-art equipment and technologies in place.

Keeping with the idea of providing the highest quality medical aid for free even to the poorest, the hospital converted all its VHS (analogue tapes), and patient records into a digitised format. This allows doctors to pull up patients' records, at any given time, on their systems. The hospital also has a 1 Gbps LAN (Local Area Network) connection.

To facilitate the conversion and archiving of analogue tapes is where MatrixView came into the picture with their proprietary EchoView system. Recommended by a visiting surgeon from the USA, who saw EchoView in action in a few Auatralian hospitals, Sri Sathya Sai Institute decided to do away with its analogue archiving systems in favour of the new technology.

As mentioned earlier, EchoView is a hardware solution that captures the Echocardiogram directly while the scan is in progress. These images are then optimised with ABO (Adaptive Binary Optimisation), a proprietary compression technology, and archived in MatrixView's .mvu format. Using an existing LAN network, such images are easily retrieved.

The Upside
Does EchoView help the institute to get the desired results? What about the cost involved? How does it benefit the patients and the hospital? Praveen Vemula, Technical Officer in charge of Hospital Administration at the institute answers, "EchoView has reduced costs and increased convenience. Doctors can now take an echocardiograph of every patient with a heart ailment and refer to it by just logging on to the local network. This ensures an easier tracking of a patient's record."

The system has been in use for six months now. The personnel of the Cardio OPD (out patients department) of the hospital, which sees a large number of patients daily, are highly impressed. However, what about the USP of software-compression of all the data with almost zero loss in quality? "Earlier we used the JPEG compression technology. This afforded us a compression of up to five per cent the original file size," says Praveen.

Medical images and files such as an echocardiogram are highly detailed, and therefore, huge. Typically, each raw image, which means each file (an MRI scan or an echo), is around 2-3 GB. A five per cent compression still leaves a file size of around 1 GB. With EchoView, which uses the ABO compression technology, the image can be compressed by around 35 times.

So instead of storing a 3 GB file, you're left with a 70 MB file. "Considering the Cardio OPD sees close to 120 patients a day, the EchoView system has saved us a huge amount of disk space, without affecting the quality of the image," opines Praveen.

Doctors can view the patients medical reports in detail

The Flipside
Coupled with space saving, minimal loss of quality, zero maintenance cost and the 24-hour accessibility, EchoView is a killer application. What could the possible grouses be? "Doctors prefer the software to be customised as per their requirements. This is taking a bit longer. Being a turnkey application this problem was expected. The hardware compatibility issues that cropped up were due to limitations of the hardware than any glitch in the software," says Praveen.

With digitised archiving of important records such as the echo and ultrasound scans, Sri Sathya Institute has taken a step further in keeping its equipment and technologies among the best in the world.

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