Computing the best high-resolution 3-D tissue images

Real-time, 3-D microscopic tissue imaging could be a revolution for medical fields such as cancer diagnosis, minimally invasive surgery and ophthalmology.

University of Illinois researchers have developed a technique to computationally correct for aberrations in optical tomography, bringing the future of medical imaging into focus.

The computational technique could provide faster, less expensive and higher resolution tissue imaging to a broader population of users. The group describes its technique this week in the online early edition of the Proceedings of the National Academy of Sciences.

“Computational techniques allow you to go beyond what the optical system can do alone, to ultimately get the best quality images and three-dimensional datasets,” said Steven Adie, a postdoctoral researcher at the Beckman Institute for Advanced Science and Technology at Illinois. “This would be very useful for real-time imaging applications such as image-guided surgery.” 

Aberrations, such as astigmatism or distortion, plague high-resolution imaging. They make objects that should look like fine points appear to be blobs or streaks. The higher the resolution, the worse the problem becomes. It’s especially tricky in tissue imaging, when precision is vital to a correct diagnosis.

Adaptive optics can correct aberrations in imaging. It’s widely used in astronomy to correct for distortion as starlight filters through the atmosphere. A complex system of mirrors smooth out the scattered light before it enters the lens. Medical scientists have begun applying adaptive optics hardware to microscopes, hoping to improve cell and tissue imaging.

“It’s the same challenge, but instead of imaging through the atmosphere, we’re imaging through tissue, and instead of imaging a star, we’re imaging a cell,” said Stephen Boppart, a professor of electrical and computer engineering, of bioengineering and of internal medicine at the U. of I. “But a lot of the optical problems are the same.”

Unfortunately, hardware-based adaptive optics are complicated, tedious to align and extremely expensive. They can only focus on one focal plane at a time, so for tomography – 3-D models constructed from sectional images as in a CT scan, for example – the mirrors have to be adjusted and a new image scanned for each focal plane. In addition, complex corrective systems are impractical for handheld or portable devices, such as surgical probes or retinal scanners.

Therefore, instead of using hardware to correct a light profile before it enters the lens, the Illinois team uses computer software to find and correct aberrations after the image is taken.

Boppart's group teamed up with with Scott Carney, a professor of electrical and computer engineering and the head of the Optical Science Group at the Beckman Institute, to develop the technique, called computational adaptive optics.

They demonstrated the technique in gel-based phantoms laced with microparticles as well as in rat lung tissue. They scan a tissue sample with an interferometric microscope, which is an optical imaging device using two beams of light.

The computer collects all of the data and then corrects the images at all depths within the volume. Blurry streaks become sharp points, features emerge from noise, and users can change parameters with the click of a mouse.

“Being able to correct aberrations of the entire volume helps us to get a high-resolution image anywhere in that volume,” said Adie. “Now you can see tissue structures that previously were not very clear at all.”

Computed adaptive optics can be applied to any type of interferometric imaging, such as optical coherence tomography, and the computations can be performed on an ordinary desktop computer, making it accessible for many hospitals and clinics.

Next, the researchers are working to refine the algorithms and explore applications. They are combining their computational adaptive optics with graphics processors, looking forward to real-time in-vivo applications for surgery, minimally invasive biopsy and more.  

Cancer Home Detection Kit

Small Liquid Sensor May Detect Cancer Instantly, Could Lead To Home Detection Kit - What if it were possible to go to the store and buy a kit to quickly and accurately diagnose cancer, similar to a pregnancy test?

A University of Missouri researcher is developing a tiny sensor, known as an acoustic resonant sensor, that is smaller than a human hair and could test bodily fluids for a variety of diseases, including breast and prostate cancers.

"Many disease-related substances in liquids are not easily tracked," said Jae Kwon, assistant professor of electrical and computer engineering at MU. "In a liquid environment, most sensors experience a significant loss of signal quality, but by using highly sensitive, low-signal-loss acoustic resonant sensors in a liquid, these substances can be effectively and quickly detected - a brand-new concept that will result in a noninvasive approach for breast cancer detection."

Kwon's real-time, special acoustic resonant sensor uses micro/nanoelectromechanical systems (M/NEMS), which are tiny devices smaller than the diameter of a human hair, to directly detect diseases in body fluids. The sensor doesn't require bulky data reading or analyzing equipment and can be integrated with equally small circuits, creating the potential for small stand-alone disease-screening systems.

Kwon's sensor also produces rapid, almost immediate results that could reduce patient anxiety often felt after waiting for other detection methods, such as biopsies, which can take several days or weeks before results are known.

"Our ultimate goal is to produce a device that will simply and quickly diagnose multiple specific diseases, and eventually be used to create 'point of care' systems, which are services provided to patients at their bedsides," Kwon said.

"The sensor has strong commercial potential to be manifested as simple home kits for easy, rapid and accurate diagnosis of various diseases, such as breast cancer and prostate cancer."

MADAM Salina Mohamed So'ot has no pulse but she is very much alive.

Madam Salina Mohamed So'ot (left) is the first recipient here to get a new artificial heart that pumps blood continuously, the reason why there are no beats on her wrist.

The 30-year-old administrative assistant is the first recipient here to get a new artificial heart that pumps blood continuously, the reason why there are no beats on her wrist.

Older artificial hearts usually mimic the heart's pulsations.

And the petite Madam Salina, who suffers from end-stage heart failure, would not have been able to use the older and bulkier models because they can only be implanted in patients 1.7m or taller.

The National Heart Centre has implanted four of these new devices since May.

Because the latest model can last longer than its predecessors, possibly for years, it can potentially be used for the long-term support of patients with irreversible heart failure.

Computer Innovation: Go to hospital to see the future - New Scientist

Innovation: Go to hospital to see computing's future - New Scientist

Computer Innovation is our regular column that highlights emerging technological ideas and where they may lead.

If you want to know how people will interact with machines in the future, head for your nearest hospital.

That's the impression I got from a new report about the future of human-computer interaction from IT analysts Gartner, based in Stamford, Connecticut.

Gartner's now-classic chart, shown right, shows the rollercoaster of expectations ridden by new technologies: rocketing from obscurity to a peak of overblown hype, then falling into a "trough of disillusionment" before finally becoming mainstream as a tech's true worth is found.

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Deadly H1N1 Swine Flu outbreak: Pandemic looms

A novel flu virus has struck hundreds of people in Mexico, and at least 18 have died. It has also infected eight people in the US, and appears able to spread readily from human to human. The World Health Organization is calling an emergency meeting to decide whether to declare the possible onset of a flu pandemic.

Ironically, after years of concern about H5N1 bird flu, the new flu causing concern is a pig virus, of a family known as H1N1.

Flu viruses are named after the two main proteins on their surfaces, abbreviated H and N. They are also differentiated by what animal they usually infect. The H in the new virus comes from pigs, but some of its other genes come from bird and human flu viruses, a mixture that the US Centers for Disease Control and Prevention calls "very unusual".

On Wednesday, the CDC announced that routine surveillance had uncovered mild flu cases during late March and April, caused by a novel swine flu virus. Those affected, aged 9 to 54, live in and around San Diego, California, and San Antonio, Texas, near the Mexican border. None was severe. Symptoms were normal for flu, with more nausea and diarrhoea than usual.

Mongrelised mix

On Thursday, Canadian public health officials warned Canadians travelling to Mexico of clusters of severe flu-like illness there. Then on Friday the WHO in Geneva said in a statement there have been around 900 suspected cases of swine flu in Mexico City and two other regions of Mexico, with around 60 suspected deaths. Of those, 18 have been confirmed as H1N1 swine flu, says the WHO, and tests so far have shown that 12 of those are "genetically identical" to the California virus.

On Friday, Richard Besser, head of the CDC, confirmed that Mexican samples tested at CDC were also "similar" to the US virus. "From everything we know to date, this virus appears to be the same," he said.

To be declared a pandemic, Besser said, the virus must be new, cause severe disease, and transmit easily enough to be sustained.

It is new. Anne Schuchat, head of science and public health at the CDC, said that the US virus is an unusually mongrelised mix of genetic sequences from North American pigs, Eurasian pigs, birds and humans. The H protein on its surface, having hitherto circulated only in pigs, is one most human immune systems have never seen, the crucial requirement for a pandemic flu.

Too late to contain

The virus's severity will depend on how many people who catch it die. While suspect deaths in Mexico are being tested for H1N1, is not yet known how many mild cases of virus there may have been in the affected region that have gone untested. Both numbers are needed to calculate how deadly a case might be. One ominous sign, however, is that the Mexican cases are said to be mainly young adults, a hallmark of pandemic flu.