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Technology Frontier

Jan 2011 Issue

Radiation-free system for scoliosis diagnosis

Future of bone deformity scanning points to non-invasive 3D ultrasound

All parents want the best for their children and pay great attention to their health!  But what if things are not plain sailing and their children grow up with spinal column that is less than perfect?  Around 2 to 4% of the population in Hong Kong is affected by Spinal Scoliosis, which brings the spine to an abnormal S- or C-shaped sideways curvature, and is the most common form of spinal deformity found in children.  The deformity can be stopped or reversed in some cases, but it will take years of repeated doctor visits, treatments or therapies, physical and frequent X-rays examinations.  Now, with PolyU's ground breaking ultrasound imaging technology, children with scoliosis can say goodbye to X-ray and can move around jolly soon enough with shorter journey to recovery.

Comprising an ultrasound unit, a spatial sensor and a computer with dedicated software, this novel 3D imaging technology uses ultrasound B-mode image to scrutinize abnormal spines.  But, wait a minute. Ultrasound is rarely used in imaging of bones because the waves do not pass well through this hard structure. Cleverly so the researchers from the Department of Health Technology and Informatics have turned this big disadvantage into good use.

It is recommended that a child is limited to one full-body X-ray examination per year  and that is the gold standard for examining Scoliosis. In other words, no physical examination or assessment of treatment can be done in between. With this radiation-free alternative, 3D scan of the spine can now be obtained as often as required. Timely intervention becomes possible and that is of paramount importance because the unhealthy curve can progress rapidly as the child grows. It also makes a reliable clinical tool that comes with new freedom in keeping up with outcomes and the effect of change to treatment. Physicians can now better personalize treatment plans for better result. This helps speed up recovery, which would otherwise take over a period of several years.

The scan is simple. Bone will block most of the high-frequency sound waves, and the surface of spinal column shows up in bright colour. During a scan the patient stands up and the operator touches the transducer gently against the back and sweeps up along the spine. The ultrasound waves are generated and rapidly scan to produce a series of images, each of which is a two dimensional slice through the body. On a computer with customized software, a 3D model of the full spine is built up from a series of these slices. “The resulting model can be rendered, manipulated, viewed in 3D, and even projected into a 2D image, similar to X-ray image, for curve measurement,” explained Prof Zheng Yongping, the principle investigator of this research project.

One X-ray image can provide bone deformity in only its projection plane. Although a vivid 3D image can be obtained through Magnetic Resonance Imaging (MRI), such a scan may lack the true rotary shape and curvature of a twisted spine, which is quite common with Scoliosis. Prof Zheng explained further, "During a scan, a patient would have to lie flat in the MRI machine, and the rotary curve flattens out as a result." Unlike MRI, this 3D ultrasound method allows the scan to be taken with the person standing and sitting upright, producing a 3D model revealing with excellent precision the lateral curvature along with the rotary shape and curve that an effective treatment relies upon. Let alone the fact that this useful scan is only at a fraction of MRI cost.

Scoliosis affects approximately 12 million people worldwide, mostly children. A diagnosis of Scoliosis can be quite a bombshell for both children and their families. Parents would be anxious and frustrated about the years of repeated clinic visits and examinations that lie ahead. And the thought is quite disturbing about putting their children through repeated X-rays at this young age. "This non-invasive and cost effective alternative really gives them peace of mind," commented Prof Zheng. Furthermore, this new radiation-free system can be used for mass screening of scoliosis during regular body check for children, thus it can help to find the scoliosis at a much earlier stage to provide more effective treatments.

Coupled with its potential in boosting outcome and accelerate recovery, this innovative technology might show the way forward for imaging of bone surface by ultrasound. Coming under spotlight it has called for media attention. Recently, it has won a Silver award at the International Trade Fair >>Ideas - Inventions – New Products<< in Germany, adding to the heat as it helps the spine grow healthily. A local company is now discussing with PolyU for licensing this technique, which includes three patents, and plans to commercialize it in one to two years. Thousands of Scoliosis patients can soon benefit from this invention.