An objective spinal motion imaging assessment (OSMIA): reliability, accuracy and exposure data

BACKGROUND: Minimally-invasive measurement of continuous inter-vertebral motion in clinical settings is difficult to achieve. This paper describes the reliability, validity and radiation exposure levels in a new Objective Spinal Motion Imaging Assessment system (OSMIA) based on low-dose fluoroscopy and image processing. METHODS: Fluoroscopic sequences in coronal and sagittal planes were obtained from 2 calibration models using dry lumbar vertebrae, plus the lumbar spines of 30 asymptomatic volunteers. Calibration model 1 (mobile) was screened upright, in 7 inter-vertebral positions. The volunteers and calibration model 2 (fixed) were screened on a motorised table comprising 2 horizontal sections, one of which moved through 80 degrees. Model 2 was screened during motion 5 times and the L2-S1 levels of the volunteers twice. Images were digitised at 5fps. Inter-vertebral motion from model 1 was compared to its pre-settings to investigate accuracy. For volunteers and model 2, the first digitised image in each sequence was marked with templates. Vertebrae were tracked throughout the motion using automated frame-to-frame registration. For each frame, vertebral angles were subtracted giving inter-vertebral motion graphs. Volunteer data were acquired twice on the same day and analysed by two blinded observers. The root-mean-square (RMS) differences between paired data were used as the measure of reliability. RESULTS: RMS difference between reference and computed inter-vertebral angles in model 1 was 0.32 degrees for side-bending and 0.52 degrees for flexion-extension. For model 2, X-ray positioning contributed more to the variance of range measurement than did automated registration. For volunteer image sequences, RMS inter-observer variation in intervertebral motion range in the coronal plane was 1.86 degreesand intra-subject biological variation was between 2.75 degrees and 2.91 degrees. RMS inter-observer variation in the sagittal plane was 1.94 degrees. Radiation dosages in each view were below the levels recommended for a plain film. CONCLUSION: OSMIA can measure inter-vertebral angular motion patterns in routine clinical settings if modern image intensifier systems are used. It requires skilful radiography to achieve optimal positioning and dose limitation. Reliability in individual subjects can be judged from the variance of their averaged inter-vertebral angles and by observing automated image registration

Mapping Britain's underworld. BBC Radio 4, May 25th 2012

Four million holes are dug every year in the UK. Five billion pounds are lost through the economic effects of disruption and traffic hold ups, while hitting a utility pipe or cable can prove fatal for those working on the road. Adam Hart-Davis reports on a major research project which is trying to solve the problems.He takes us underground from his ancient ice house at the bottom of his Devon garden to report on Mapping the Underworld, the £3.5m programme involving universities throughout Britain. The aim is to improve how we locate the increasingly confusing and complex array of pipes, cables and sewers beneath our streets, and assess their condition - as well as ultimately providing a better map of what is beneath our cities to improve planning both above and below ground.At the moment it's often difficult to know where such utilities are - an estimated one in four of all holes are dug in the wrong place. Maps may not be accurate because original records of where the pipes and cables are located often use reference points on the surface which have long since gone.Existing sensors may have problems finding what is underground because of soil or weather conditions, while modern materials such as plastic or fibre optics pose a challenge to existing technologies.Adam Hart-Davis tries out the prototype of a multi-sensor cart where four different sensors operate together to produce an all-in-one solution, so if one technology doesn't work well in certain conditions and with particular materials, another one will. It is not an easy undertaking for the research teams or, as it turns out, for Adam testing the multi-sensor cart

Tree root detection from ground surface vibration measurements

Rapid development of urban infrastructure in past decades together with a relatively recent growth of awareness of its impact on the natural environment result in an increased interest in non-destructive ground interrogation methods. Tree root damage is a very well known issue in civil engineering and can emerge as road surface fracture, building foundations disintegration or pipe penetration, among others. In this paper we investigate the feasibility of using a vibroacoustic method for tree root mapping. The core of the idea is that the mechanical waves induced by an excitation mechanism acting on the tree trunk propagate to the roots and then radiate into the surrounding soil. Owing to that, the response measured at the ground surface contains the contribution of waves radiating from roots and can be used for mapping their extent. In this paper, we report a set of field experiments on a ‘purpose-built’ root-trunk model buried underground. These preliminary results both demonstrate the technique and shed light on related challenges and limitations

Tree root detection from ground surface vibration measurements

Rapid development of urban infrastructure in past decades together with a relatively recent growth of awareness of its impact on the natural environment result in an increased interest in non-destructive ground interrogation methods. Tree root damage is a very well known issue in civil engineering and can emerge as road surface fracture, building foundations disintegration or pipe penetration, among others. In this paper we investigate the feasibility of using a vibroacoustic method for tree root mapping. The core of the idea is that the mechanical waves induced by an excitation mechanism acting on the tree trunk propagate to the roots and then radiate into the surrounding soil. Owing to that, the response measured at the ground surface contains the contribution of waves radiating from roots and can be used for mapping their extent. In this paper, we report a set of field experiments on a ‘purpose-built’ root-trunk model buried underground. These preliminary results both demonstrate the technique and shed light on related challenges and limitations

Tree root detection from ground surface vibration measurements

Rapid development of urban infrastructure in past decades together with a relatively recent growth of awareness of its impact on the natural environment result in an increased interest in non-destructive ground interrogation methods. Tree root damage is a very well known issue in civil engineering and can emerge as road surface fracture, building foundations disintegration or pipe penetration, among others. In this paper we investigate the feasibility of using a vibroacoustic method for tree root mapping. The core of the idea is that the mechanical waves induced by an excitation mechanism acting on the tree trunk propagate to the roots and then radiate into the surrounding soil. Owing to that, the response measured at the ground surface contains the contribution of waves radiating from roots and can be used for mapping their extent. In this paper, we report a set of field experiments on a 'purpose-built' root-trunk model buried underground. These preliminary results both demonstrate the technique and shed light on related challenges and limitations.</p