An Ultrasonic Based System to Measure Inter Spinous Process Distance in Humans: A Pilot Study

ABSTRACT The objective of this research project was to develop an ultrasonic based testing system and evaluate its application on human volunteers to locate and assess the distance between adjacent lumbar vertebrae. Tests were performed on ten volunteers aged between 19 and 29 years old during two sessions. The participants were asked to lie face down on a table with lower back section uncovered while the tests were executed. A computer controlled ultrasonic system was designed for this application. A single element 3.5 MHz immersion transducer held by a customized assembly was used to propagate and receive the ultrasonic signals. The transducer was moved along the assembly to fully scan at least two contiguous spinous processes. A Lab view based program was designed to generate a twodimensional image (B-scan) that display the shape and position of the bone tips as well as the distance between them. The standard deviation obtained from the measurements of the distance between the tips of the spinous processes of human subjects, in a given session ranged from 0.1-0.48mm. The difference between two sessions had a mean of 0.85-0.95 mm and a standard deviation of 0.87-1.03mm with reliability coefficients greater than 0.95. The study demonstrated the viability of utilizing ultrasound to precisely measure the distance between spinous processes of adjacent lumbar vertebrae