An article recently published in Scoliosis and Spinal Disorders examines the reliability of a new radiation-free system for the imaging of spinal deformities in scoliosis patients.
People who suffer from scoliosis experience abnormal curvature of the spine in all three dimensions. The most common form of this disorder is known as Adolescent Idiopathic Scoliosis (AIS), occurring in approximately 5% of children in most countries. Monitoring individuals who have scoliosis is particularly important in planning treatment, assessing the success of treatment, and observing progression of the disease. Currently, the best way to monitor scoliosis is through a form of imaging known as radiography, which includes X-rays. The images generated by these procedures are analyzed using the Cobb Method to determine the angle of the spine. The Cobb Method is currently the gold standard for examining patients with scoliosis but is associated with one significant problem: every time an individual gets an X-ray they are exposed to radiation. Because of the fact that children with scoliosis must be monitored frequently, this radiation exposure can be relatively high and is associated with problems such as increased risk for breast, lung, and blood cancers.
The inherent problems associated with the use of radiographic imaging for monitoring scoliosis progression has led to the development of new methods that do not involve radiation exposure. One such technique is known as the Scolioscan. This imaging technique is a 3D ultrasound system in which a probe is used that contains a sensor to detect position and orientation. The ultrasound probe is moved up the length of a patient’s spine to collect images. These images are integrated with the information collected regarding position of the probe to generate a 3D picture of the spine. From this image, the angle of the spinal deformity can be assessed. In a paper recently published in Scoliosis and Spinal Disorders a group of researchers set out to determine the reliability of this imaging system as well as to compare it to radiographic imaging and the Cobb Method.
In this study, the investigators assessed the reliability of the measurements determined from Scolioscan images taken by the same operator as well as by different operators. To do this, they had two different people conduct imaging on 20 scoliosis patients and three different people perform spinal angle measurement on these images. These measurements were determined using a computer program included with the Scolioscan software that conducts volume projection imaging. By doing this, the researchers found that Scolioscan shows very good reliability when scans are completed by the same individual as well as when they are completed or interpreted by different individuals. This is important, as for an imaging system to be useful in monitoring a disease, it must be consistent over time and between operators.
Additionally, this study wanted to compare Scolioscan to the examination of X-rays using the Cobb method. They did this by analyzing the results of the two imaging systems for 49 patients with scoliosis. All Scolioscan images and spinal angle measurements were completed by one individual while X-rays were interpreted by a medical doctor with many years of experience. The researchers found a moderate correlation between the results of the two imaging systems. Furthermore, they found that Scolioscan is prone to underestimating the spinal deformity of a patient compared with the Cobb method. It was found that a linear equation could adjust angles measured from Scolioscan to match those determined by the Cobb method. However, this analysis was only done for 49 patients. Although this conversion equation could be useful, it is unclear whether it would apply to the entire population of scoliosis patients.
A radiation-free method for examining scoliosis patients is highly necessary. Although a new 3D ultrasound system known as Scoliscan is reliable between different operators, it has been shown to underestimate the deformity of a patient’s spine. This technology has the potential to be extremely useful in monitoring the progression of scoliosis as it can be performed repeatedly while posing a low risk to the patient. However, the current system requires improvement before widespread implementation is possible. This is in part because Scolioscan is not able to accurately measure spinal angle in patients with a protruding shoulder blade, approximately 10% of scoliosis patients, or those that are overweight. If improvements can be made to this system to overcome these issues, as well as the fact that it underestimates spinal deformity, it holds a great deal of potential for improving the safety of current scoliosis imaging techniques.
Written By: Katrina Cristall, BSc (Hons)